scorpio

scorpio

Lv10

21 Followers
0 Following
0 Helped

ANSWERS

Published8911

Subjects

History23Law7Management1English12Philosophy1Anthropology12Marketing1Science17Geography86Algebra5Computer Science24Accounting36Calculus1Biology7724Mathematics7Physics3Finance1Economics870Chemistry80

1)Two hundred years ago, the fly species Rhagoletispomonella only laid its eggs on fruit of the hawthorn tree.Today, different "host races" of R. pomonella lay theireggs on hawthorns OR apples. Apples occur within the range ofhawthorns, so divergence between apple flies and hawthorn fliescould be the first step in sympatric speciation. Choose theevidence that supports that R. pomonella is undergoingsympatric speciation. Check all that apply.

a)Apple flies typically mate withapple flies, and hawthorn flies typically mate with hawthornflies.
b)Apple flies and hawthorn fliesemerge from their hosts at different times of the year.
c)Apple flies and hawthorn fliesare able to form fertile hybrids.
d)Apple flies and hawthorn fliesare physically indistinguishable from each other.

2)The most common mechanism for sympatric speciation in plantsis

a)polyploidy.
b) geographic isolation.
c)spontaneous mutation.
d)punctuated equilibrium.
e)disruptive selection.

The biological species concept of Ernst Mayr cannot be appliedto

a)sympatric organisms.
b)allopatric organisms.
c)eukaryotic organisms.
d)prokaryotic organisms.
e) asexually-reproducingorganism

3) Indicate the scenario(s) that could directly result insympatric speciation. Check all that apply.

a)Two sunflower species cross toform a healthy hybrid individual with equal copies of chromosomesfrom each parental species.
b)A new river channel divides apopulation of beetles into two populations.
c)A small group of birds aretransported to a new volcanic island during a hurricane.
d)A subset of parasitic flieswithin a larger population colonizes a new host plant.
Answer:b)Apple flies and hawthorn fliesemerge from their hosts at different ti...

Show transcribed image text
Answer:5) often a limiting nutrient Alligators excavate holes in the bottom of...
Answer:Ecological succession is the process by which the mix of species and ha...
Answer:A mean NPP e
Answer: net primary productivity
Answer:Total mass of biological life
Answer:net primary productivity
Answer:visible light has more energy than ultraviolet radiation e. infrared en...

The total amount of energy invested in the production of living biomass in a community is that community's

Select one:

a. gross primary productivity

b. net primary productivity

c. gross photosynthetic efficiency

d. net photosynthetic efficiency

Which of the following factors accounts for the largest number of documented extinctions that have occurred in the last 1,000 years?

Select one:

a. Deforestation

b. Habitat fragmentation

c. Pollution

d. Invasive species

In terrestrial ecosystems, the greatest current cause of species endangerment is

Select one:

a. invasive species

b. habitat loss

c. overharvesting

d. pollution

Carbon dioxide has a warming effect on the earth's atmosphere. This is because it absorbs

Select one:

a. ultraviolet radiation coming from the earth's surface

b. visible light coming directly from the sun

c. ultaviolet radiation coming from the sun

d. infrared radiation coming from the earth's surface

The overall productivity of the open ocean has declined as a result of global warming.This is believed to be because

Select one:

a. ocean stratification has intensified

b. cloud cover has increased, reducing sunlight over the ocean

c. higher temperatures have directly inhibited algal photosynthesis

d. the amount of carbon dioxide dissolved in the ocean has decreased

Positive feedback might occur in response to increasing atmospheric carbon dioxide levels as a result of

Select one:

a. soil decomposers increasing the rate at which they break down organic molecules

b. oceans absorbing more carbon dioxide in the form of bicarbonate ions

c. an increase in the rate at which fossil fuels are formed

d. plants accelerating their growth by taking up more carbon dioxide

Which nitrogen-containing molecules in soil represent a usable source of nitrogen for plants?

Select one:

a. Nitrogenous bases of nucleic acids

b. All of these

c. Ammonium

d. Amino acids

In a tropical forest ecosystem, "edge” habitat is considered to be of relatively low quality for conservation purposes because it

Select one:

a. tends to contain more invasive species

b. all of these

c. tends to contain more early-successional species

d. is more exposed to the effects of wind

Answer: B C D B B A A C

The total amount of energy invested in the production of living biomass in a community is that community's

Select one:

a. gross primary productivity

b. net primary productivity

c. gross photosynthetic efficiency

d. net photosynthetic efficiency

Which of the following factors accounts for the largest number of documented extinctions that have occurred in the last 1,000 years?

Select one:

a. Deforestation

b. Habitat fragmentation

c. Pollution

d. Invasive species

In terrestrial ecosystems, the greatest current cause of species endangerment is

Select one:

a. invasive species

b. habitat loss

c. overharvesting

d. pollution

Carbon dioxide has a warming effect on the earth's atmosphere. This is because it absorbs

Select one:

a. ultraviolet radiation coming from the earth's surface

b. visible light coming directly from the sun

c. ultaviolet radiation coming from the sun

d. infrared radiation coming from the earth's surface

The overall productivity of the open ocean has declined as a result of global warming.This is believed to be because

Select one:

a. ocean stratification has intensified

b. cloud cover has increased, reducing sunlight over the ocean

c. higher temperatures have directly inhibited algal photosynthesis

d. the amount of carbon dioxide dissolved in the ocean has decreased

Positive feedback might occur in response to increasing atmospheric carbon dioxide levels as a result of

Select one:

a. soil decomposers increasing the rate at which they break down organic molecules

b. oceans absorbing more carbon dioxide in the form of bicarbonate ions

c. an increase in the rate at which fossil fuels are formed

d. plants accelerating their growth by taking up more carbon dioxide

Which nitrogen-containing molecules in soil represent a usable source of nitrogen for plants?

Select one:

a. Nitrogenous bases of nucleic acids

b. All of these

c. Ammonium

d. Amino acids

In a tropical forest ecosystem, "edge” habitat is considered to be of relatively low quality for conservation purposes because it

Select one:

a. tends to contain more invasive species

b. all of these

c. tends to contain more early-successional species

d. is more exposed to the effects of wind

Answer: B a c d a a

Decomposers such as fungi and bacteria are vital to the ecosystem because of they

a.

are the primary organic recyclers.

b.

are the terminal energy consumers.

c.

keep populations in check.

d.

help to lower greenhouse gases.

1 points

QUESTION 5

Which of the following will not be a result of global warming?

a.

Global temperatures will continue to rise because of increased carbon dioxide levels.

b.

The acidification of the oceans will continue and will affect marine life.

c.

Severe weather will increase because of rising temperatures.

d.

Species with narrow habitat tolerances will outcompete species with broader tolerances.

1 points

QUESTION 6

The annual increase in carbon dioxide results from two human activities. Burning fossil fuels accounts for _____ percent of the increase, and deforestation causes the remaining _____ percent.

a.

30; 70

b.

40; 60

c.

50; 50

d.

75; 25

1 points

QUESTION 7

In the nitrogen cycle, which of these organisms convert atmospheric nitrogen gas into a form that can be utilized by plants?

a.

Bacteria

b.

Consumers

c.

Decomposers

d.

Omnivores

1 points

QUESTION 8

Fertilizer runoff into ponds and lakes

a.

reduces soil nutrients at the bottom of the pond.

b.

benefits organisms in the pond by decreasing NPP.

c.

causes aerobic bacteria to deplete available oxygen.

d.

increases the available oxygen in the pond.

1 points

QUESTION 9

All life on Earth, except the life in deep sea vent and hot spring ecosystems, depends on ________ energy.

a.

solar

b.

synthetic

c.

chemical

d.

heat

1 points

QUESTION 10

The majority of the energy available in an ecosystem is actually ________ as heat energy.

a.

gained

b.

recycled

c.

reabsorbed

d.

transformed

Answer: C B B A D D

2) Which of the following best represents the decomposers you would find as detritus moves through the stages of decomposition? a. Large invertebrates, mites, fungi, earthworm b. Large invertebrates, earthworm, mites, fungi c. Earthworm, small invertebrates, fungi, mites d. Small invertebrates, fungi, bacteria, ants e. Small invertebrates, earthworms, ants, bacteria

3) Which of the following is not a reason that decomposition is important from an ecosystem perspective a. most of the primary production energy goes into decomposition not higher trophic levels b. decomposition allows energy to be recycled back into the ecosystem c. decomposition organisms can represent an important link between trophic levels d. decomposition helps to breakdown feces e. decomposition recycles nutrients

4) When we extract fossil fuels from the earth and use them (ie, convert them to CO2), we are adding carbon to the global carbon cycle that represents which of these: a. Carbon that would normally cycle through ocean carbon cycling b. Carbon that would normally enter the gaseous phase of the carbon cycle anyway c. Carbon that would cycle quickly d. Carbon that would normally cycle very slowly e. None of the above

5) Choose all of the following that would decrease decay rates a. Very low temperatures with abundant moisture compared to moderate temps with abundant moisture b. An area that does not contain small arthropods and must rely on bacteria and fungi for decomposition compared to an area with plentiful small arthropods c. The presence of secondary plant toxins compared to a plant that does not contain toxins d. Decreased C:N compared to a higher C:N e. All of the above

6) What would be the most likely effect on most plants (assuming that they lack symbiont microorganisms) of an increased availability of nitrogen gas? a. An increased growth rate b. Decreased growth rate, because the nitrogen gas would interfere with photosynthesis c. An accelerated metabolic rate d. No effect, because plants do not require nitrogen e. No effect, because plants cannot use nitrogen gas

7) Use the figure to the right. Which of the following represent immobilization? a. b. c. d. e.

8) Many human activities can disrupt nutrient cycles. Which of the following represents an incorrect nutrient, activity match? a. P Cycle, Increasing flight traffic b. Hydrologic Cycle, Using groundwater faster than it is replenished c. N Cycle, Acid Rain d. N Cycle, Coal Combustion e. C Cycle, Coal Combustion

9) Which of the following is not a reason why we use litter bags to measure decay rate? a. Litter bags prevent the litter from being moved b. Litter bags allow exchange of gases and moisture c. Litter bags allow decomposers to still have access to the litter d. All of the above are reasons e. None of the above

10) If seedlings are grown in a beaker of distilled water in a sunny window, which of the following nutrients will be available to them from the environment in a usable form? a. Nitrogen b. Carbon c. Phosphorous d. Both a and b e. All of the above

Answer: A C D C A B D A

1. You have conducted an experiment using litterbags to assess the effect of lignin content on leaf decomposition rate. You selected 6 tree species with a range of leaf lignin levels. Which of the following is a plausible prediction for your study?

A. The biomass of leaf litter bags will increase more in plants with higher leaf lignin content.
B. The biomass of leaf litter in the bags will be greater in leaves with higher lignin content after the same length of time.
C. The leaf litter bags cannot be used to conduct this experiment.
D. The biomass of leaf litter in the bags will be lower in leaves with higher lignin content after the same length of time.

E. The CO2 captured in the bags will increase over time.

.

2. Which of the following statements about nutrient cycles is FALSE?

A. Litterbag experiments are useful for determining the changes in nitrogen content within dead leaves.
B. After the initial period of decomposition, nitrogen content of leaf litter increases.
C. The nitrogen level in leaf litter declines at the onset of decomposition.
D. As mineralization continues, the nitrogen concentration in the leaf litter can rise above 100 percent.
E. Leaves with lower nitrogen content are of higher quality for decomposers.

.

3. You have been asked to draw a graph of litter decomposition in a forest over time. Your graph has the rate of carbon lost on the y-axis and time on the x-axis. It begins at 100 percent and has a strong decline for the first portion, but then it levels off with a far lower slope as time continues. Please explain this trend.

A. This change from a rapid decomposition rate to a slower decomposition rate reflects the preferential consumption of easily digested, high-energy carbon compounds early in decomposition.
B. This change reflects the preferential consumption of larger, more complex carbon-compounds first, followed by high-energy compounds being digested later in decomposition.
C. The initial decomposition rate is rapid because there are a number of decomposers that have been drawn to the site. The decline is the result of competition among decomposers leading to only the winners having access, slowing the decomposition rate.
D. The decline in decomposition rate is because the carbon dioxide released by the decomposers becomes toxic to the decomposers and causes dieback of sensitive decomposers.
E. This change from a rapid decomposition rate to a slower decomposition rate reflects the satiation of the decomposers.

.

4. Roots exude high-quality, energy-rich carbon into the rhizosphere. It is hypothesized that this exudate functions to enhance decomposition rates. All of the following lend support to this hypothesis with one exception. Choose the EXCEPTION.

A. The carbohydrates exuded from plant roots may account for as much as 40 percent of dry matter production of plants.

B. Bacterial decomposition rates are much higher in the presence of these exudates.

C. Bacteria have been found in mutualisms with plant roots and they grow much more slowly without the root exudates.

D. Plants release CO2 gas into the rhizosphere to alter the pH and cause increased mobility of cation nutrients.

E. When provided with exudates, bacterial growth is limited most strongly by nutrient availability because the exudates are energy rich, but very low in nitrogen.

.

5. Which of the following statements concerning the influence of currents in vertical transport of nutrients is true?

A. The Hadley effect drives the patterns of surface currents.
B. Equatorial waters are rather nutrient-poor due to the lack of mixing and temperature stratification that exists.
C. Along the western margins of the continents, the surface waters are pushed offshore by the Coriolis effect, resulting in deeper, more nutrient-rich waters being transported vertically to the surface.
D. The lateral movement of water extends about 50m into the water column.
E. Upwelling of nutrients occurs on the east coasts of continents as warm water flows down and forces cool water up.

.

6. What is swidden agriculture?

A. a form of traditional agriculture that is being employed in many parts of the tropics to meet the ever-increasing demand for land
B. a traditional method of agriculture in which trees and other vegetation are cut and burned to clear land
C. agriculture that uses naturally occurring fertilizers, such as manure and dead plant materials
D. agriculture that uses synthetic soil fertilizers between harvests to supplement soil nutrients
E. a common form of high-intensity cultivation that involves monoculture production of crops
Answer: B A B B C D
Answer: Breaking chemical bonds in simple sugars requires a relatively large a...
Answer: B
Answer: C
Answer: C
Answer:These percentages are determined based on the fact that each of the 4 o...

1. Cyclic GMP is an intracellular second messenger. How does cyclic GMP cause an erection of the penis?

A. When cyclic GMP relaxes smooth muscle, more blood can flow through veins in the penis, causing an erection.
B. Cyclic GMP causes smooth muscle relaxation so that arterioles can dilate, allowing blood to fill the corpora cavernosa and corpora spongosium causing an erection
C. Cyclic GMP is destroyed by an enzyme, allowing arterioles to become engorged with blood, which produces an erection.
D. Cyclic GMP causes the release of nitric oxide during sexual excitement, which causes the erection.
E. Cyclic GMP stimulates the synthesis of phosphodiesterase 5 (PDE5) that dilates the veins in the penis causing an erection

2. A newborn who is accidentally given a drug that destroys the thymus would most likely ________.
A. lack class I MHC proteins on cell surfaces
B. lack innate immunity
C. be unable to genetically rearrange antigen receptors
D. be unable to differentiate and mature T cells
E. have a reduced number of B cells and be unable to form antibodies

3. Pick the choice that describes the major difference between the B-cell receptor and the T-cell receptor.
A. The T-cell receptor requires help interacting with its specific antigen but the B-cell receptor does not.
B. The B-cell receptor is specific for bacteria; the T-cell receptor is specific for viruses.
C. The T-cell receptor is never released into the bloodstream, but the B-cell receptor becomes an antibody.
D. The T-cell receptor exhibits specificity but the B-cell receptor does not.
E. The B-cell receptor consists of two polypeptide chains; the T-Cell receptor consists of two heavy and two light polypeptide chains

4. Karen and Steve each have a sibling with sickle-cell disease. Neither Karen nor Steve nor any of their parents have the disease, and none of them have been tested to see if they have the sickle-cell trait. Based on this incomplete information, what is the probability that if this couple has two children both will have the disease?
A. 1/4
B. 1/8
C. 1/9
D. 1/36
E. 1/12

5. Using the information in question 4 what is the probability of Karen and Steve having two sons with the disease?
A. 1/16
B. 1/24
C. 1/144
D. 1/256
E. 1/48

6. In a diploid set of chromosomes, one member of each pair of homologous chromosomes is derived from the father (paternal), and the other comes from the mother (maternal). If 2n = 10, what is the probability that a particular gamete will contain only paternal chromosomes?
A. 1/4
B. 1/8
C. 1/16
D. 1/32
E. The answer cannot be determined from these data.

7. Where would a ligand-gated ion channel typically be found on a neuron?
A. presynaptic membrane
B. axon hillock
C. axon
D. ligand-gated ion channels are not found on neurons.
E. postsynaptic membrane

8. In rabbits, the homozygous CC is normal, Cc results in deformed legs, and cc results in very short legs. The genotype BB produces black fur, Bb brown fur, and bb white fur. If a cross is made between brown rabbits with deformed legs and white rabbits with deformed legs, what percentage of the offspring would be expected to have deformed legs and white fur?
A. 25 percent
B. 33 percent
C. About 66 percent
D. 100 percent
E. 50 percent

9. Suppose there was a mutation in the segment polarity genes of Drosophila. What do you suppose might be the outcome?
A. Several segments of the embryo will be missing.
B. Every other segment of the embryo will be missing.
C. Legs will appear in the place of antennae.
D. Antennae will appear in a different part of their usual segment.
E. There will be an extra set of wings from segments in the thorax

10. A bone marrow transplant may not be appropriate from a given donor (Jane) to a given recipient (Jane's cousin Bob), even though Jane has previously given blood for one of Bob's needed transfusions. Which of the following might account for this?
A. A blood type match is less stringent than a match required for transplant because blood is more tolerant of change.
B. Jane's blood type is a match to Bob's, but her MHC proteins are not.
C. For each gene, there is only one blood allele but many tissue alleles.
D. Jane's class II genes are not expressed in bone marrow.
E. Bob's immune response has been made inadequate before he receives the transplant.

11. Which type of transmembrane protein is directly responsible for maintaining the propagation of action potentials across an axon once it has been initiated?
A. voltage-gated sodium channels
B. sodium-potassium pumps
C. voltage-gated potassium channels
D. voltage-gated calcium channels
E. All of the above

12. Which of the following correctly pairs up a type of synapse and its characteristic?
A. electrical synapse ... neurotransmitters
B. junctional synapses ... ligand-gated ion channels
C. chemical synapses ... gap junctions
D. electrical synapse…Ca2+ influx
E. electrical synapse ... gap junctions

13. In a submarine expedition to the ocean bottom, you discover a population of fish that are only female. What type of reproduction does this fish most likely use?
A. cloning
B. budding
C. sexual
D. fragmentation
E. parthenogenesis

14. Threshold is of great significance in the physiology of neurons. What happens if threshold is NOT reached?
A. the neuron cannot regain its resting potential
B. the action potential will be "inversed," with a flux of sodium out of the cell rather than into it
C. positive-feedback depolarization will not occur
D. an action potential will be reached
E. salutatory conduction would occur down the axon

15. Exposure to chemicals that cause mutations in DNA greatly increases the chance of developing cancer. Mutations that inactivate which of the following proteins would most likely lead to cancer?
A. tubulin
B. cyclin
C. cyclin dependent kinase
D. mdm2
E. p21

Questions 16-18 are related to the figure of the life cycle below.


16. If the zygote's chromosome number is 10, which of the following will be true?
A. The sporophyte's chromosome number per cell is 10 and the gametophyte's is 5.
B. The sporophyte's chromosome number per cell is 5 and the gametophyte's is 10.
C. The sporophyte and gametophyte each have 10 chromosomes per cell.
D. The sporophyte and gametophyte each have 5 chromosomes per cell.
E. The sporophyte's chromosome number per cell is 20 and the gametophyte's is 10.

17. At what number(s) does mitosis occur?
A. 2 and 3
B. Only 2
C. Only 3
D. 1,2, and 3
E. Only 4

18. At what number(s) does meiosis occur?
A. 2 and 3
B. Only 2
C. Only 3
D. 1,2, and 3
E. Only 4

19. Given the parents AaBbCcDdEe × AaBbCcddee, assume simple dominance and independent assortment. What proportion of the progeny will be expected to phenotypically resemble the first parent?
A. 1/8
B. 1/4
C. 3/64
D. 9/128
E. 27/256


20. In question 19, how many different genetically kinds of gametes are produced by the first parent?
A. 4
B. 8
C. 16
D. 32
E. 64

Use the key below to answer questions 21-24.
A. The statement is true for mitosis only.
B. The statement is true for meiosis I only.
C. The statement is true for meiosis II only.
D. The statement is true for mitosis and meiosis I
E. The statement is true for mitosis and meiosis II

21. A cell divides to produce two daughter cells that are genetically identical.

22. Homologous chromosomes synapse crossing over occurs.

23. Centromeres uncouple and chromatids are separated from each other.

24. Independent assortment of chromosomes occurs.

25. The process is preceded by replication of the DNA.

26. Why does a mutation in a Drosophila pair-rule gene affect the expression of segment polarity genes but not gap genes?
A. Pair-rule gene products act as morphogens.
B. Pair-rule genes are a type of effector gene.
C. Pair-rule genes are located below segment-polarity and above gap genes in the regulatory gene cascade.
D. Pair-rule genes are located above segment polarity and below gap genes in the regulatory gene cascade.
E. Pair rule genes are controlled by egg-polarity genes

27. The interplay of multiple excitatory and inhibitory inputs most affects what part of a post-synaptic neuron?
A. dendrites
B. the nucleus
C. the neuron's cytoskeleton
D. the axon
E. axon hillock


28. Your five-year-old sister has just come home from day care feeling poorly and not eating. The next day, she has vomiting, a rash, diarrhea, and some neurological symptoms. The diagnosis is bacterial meningitis, a contagious bacterial infection, usually not life-threatening. Within a week, she is up and about again, apparently healthy. The little boy who lives next door to you gets this same disease three months later, and you become worried that your sister will again get meningitis. They play together all the time, and he could easily transmit the bacterium to her during play. Is this a potential problem?
A. No, your sister is not at risk for contracting meningitis again, particularly because the time span between the first exposure and second exposure to this infectious agent is not very long. Upon "seeing" the bacteria again, her memory cells from the previous exposure will become activated very quickly, making large amounts of protective antibody.
B. Yes, your sister is at risk for contracting meningitis again. Very young children have immature immune systems that will not protect them.
C. Yes, your sister is at risk for meningitis again. Bacteria do not elicit as strong an immune response as viruses do, and her immune system will not be able to contain the infection.
D. No, your sister will never be at risk for meningitis again. Once you have contacted an infectious agent and memory cells have been produced, that infectious agent will always be identified and eradicated before the infection can take place.
E. No, your sister will never be at risk for meningitis again. Once you have contacted an infectious agent and memory cells have been produced from the innate immune system, that infectious agent will always be identified and eradicated before the infection can take place.


29. In combination, the products of gap genes, pair-rule genes, and segment polarity genes _____.
A. trigger the reorganization of the larval body into an adult body
B. set up the back-to-belly axis of the larval body
C. define the segmented body plan of the embryo
D. direct cell movements during differentiation
E. direct gastrulation to form the ectoderm, mesoderm and endoderm

Answer questions 30-34 using the data and key provided below.
CROSS I. Purebred lines of wild-type fruit flies (gray body and normal wings) are mated to flies with black bodies and vestigial wings.

Figure 1

F1 offspring all have a normal phenotype.

Figure 2

CROSS II. F1 flies are crossed with flies recessive for both traits (a testcross).
Resulting Offspring Normal
Gray body; normal wings 390
Black body; vestigial wings 410
Black body; normal wings 99
Gray body; vestigial wings 101

KEY:
A. CROSS I results give evidence against the statement.
B. CROSS I results give evidence supporting the statement.
C. CROSS II results give evidence against the statement.
D. CROSS II results give evidence supporting the statement.
E. Neither CROSS I nor CROSS II results support the statement.

30. Black body and normal wings are both dominant traits.

31. The genes for body color and wing shape are not linked.

32. The genes for gray body and normal wings are on one homologous chromosome and the genes for black body and vestigial wings are on the other homologous chromosome.

33. An F1 cross should produce flies that will fall into a Mendelian 9:3:3:1 ratio.

34. There are 20 centimorgans (map units) between the genes for body color and wing shape.

35. A student athlete suffered an injury while playing soccer and subsequently has pain in her shoulder. The doctor prescribes a strong anti-inflammatory drug, such as a steroid. Her doctor warns her that an increased susceptibility to a variety of general bacterial infections, such as a sore throat, sore mouth, pneumonia, and skin infections is associated with the steroid. Based on your knowledge of the immune system and on the example in this scenario, what do you conclude about such anti-inflammatory drugs?
A. They cause a temporary condition similar to an autoimmune disease.
B. They cause bacteria to cluster in the body.
C. They inhibit a part of the innate immune system.
D. They interfere with mast cell function.
E. They suppress the adaptive immune system

In a series of mapping experiments, the recombination frequencies for four different linked genes of Drosophila were determined as shown in the figure below.

36. What is the order of these genes on a chromosome map?
A. b-rb-cn-vg
B. cn-rb-b-vg
C. vg-cn-b-rb
D. rb-cn-vg-b
E. vg-b-rb-cn

37. Gastrulation is an important event in early embryonic development. Which of the following is NOT a result of gastrulation?
A. formation of three embryonic cell layers
B. movement and alignment of many embryonic cells
C. the formation of a gastrula
D. the formation of specialized adult tissues
E. induction by the dorsal lip of the blastopore

38. In vertebrate animals, spermatogenesis and oogenesis differ in that _____.
A. cytokinesis is unequal in oogenesis, whereas it is equal in spermatogenesis
B. oogenesis produces four functional haploid cells, whereas spermatogenesis produces only one functional spermatozoon
C. oogenesis ends at menopause, whereas spermatogenesis is finished before birth
D. oogenesis begins at the onset of sexual maturity, whereas spermatogenesis begins during embryonic development
E. spermatogenesis is not completed until after fertilization occurs, but oogenesis is completed by the time a girl is born

39. Which of the following provides an example of epistasis?
A. In rabbits and many other mammals, one genotype (ee) prevents any fur color from developing.
B. In Drosophila, white eyes can be due to an X-linked gene or to a combination of other genes.
C. In cacti, there are several genes for the type of spines.
D. Recessive genotypes for each of two genes (aabb) results in an albino corn snake.
E. Both A and B are correct

40. In humans, the follicle cells that remain behind in the ovary following ovulation become _____.
A. the ovarian endometrium that is shed at the time of menstruation
B. the thickened portion of the uterine wall
C. a steroid-hormone synthesizing structure called the corpus luteum
D. the placenta, which secretes cervical mucus
E. swept into the oviduct

41. An ectopic pregnancy occurs when a fertilized egg implants somewhere other than in the lining of the uterus. Usually it implants in the oviduct. Which of the following would be the most likely explanation for such a pregnancy being unsuccessful?
A. hCG cannot be produced in the oviduct.
B. The necessary hormones cannot reach the developing fetus in the oviduct.
C. The orientation of the baby would be sideways.
D. The lining of the oviduct is unable to support the developing fetus.
E. The umbilical cord would not be able to reach the uterus

42. During the menstrual cycle the hormone ________ is primarily responsible for maintaining the corpus luteum whereas this function is taken over in the first few months of pregnancy by the hormone______.
A. LH;hCG
B. progesterone; LH
C. estradiol; hCG
D. hCG; FSH
E. progesterone; estradiol

43. At the time of fertilization, the maturation of the human oogonium has resulted in _____.
A. four secondary oocytes
B. four primary oocytes
C. one secondary oocyte
D. one primary oocyte
E. two primary oocytes

44. When Europeans first came to North America, one of the most disastrous impacts on native populations was the introduction of "Old World diseases." These diseases, such as smallpox, influenza, and plague, devastated the Native American population as the number of settlers grew steadily. One author has called this "the greatest human catastrophe in history, far exceeding ... the Black Death of Medieval Europe." Based on this scenario and what you know about the immune system, what can you conclude about the Native American and European populations?
A. Native American immune systems were inherently inferior to those of the Europeans and were not capable of developing immunity to the same microbes.
B. The Europeans had been vaccinated against all of these diseases before traveling to North America.
C. Native American immune systems had not evolved in the presence of these novel microbes and were at a great disadvantage when exposed to them over a relatively short period of time.
D. Native Americans were genetically vulnerable to these diseases, which were all caused by viruses
E. Native Americans immune systems did not have the capability of producing interferons.

45. Which of the following involves apoptosis?
A. Interactions between muscle cells and bone cells guide the growth of the muscle to a specific location so that it can attach to the bone.
B. Cells from the top of the mouth combine with cells from the base of the brain to form the pituitary.
C. A gonad begins as an undifferentiated organ that can form either an ovary or a testis. The formation depends on the hormonal signals that control the growth of some cells and the death of others.
D. If part of the developing spinal cord in a frog embryo is transplanted to under the skin of its back, it will stimulate development of an eye in that location.
E. The bones of the spinal column develop from blocks of undifferentiated tissue called somites.

46. The drug RU486 causes abortion by
A. inhibiting release of gonadotropins from the pituitary.
B. blocking progesterone receptors in the uterus.
C. preventing release of the secondary oocyte from the ovary.
D. Both A and B are correct
E. A, B, and C

47. Which of the following statements about homologous chromosomes is correct?
A. They are found in animal cells but not in plant cells.
B. They have genes for the same traits at the same loci.
C. They pair up in prophase II.
D. They are found in haploid cells.
E. They are found in the cells of human females but not in those of human males.

48. Spores and gametes are different in that __________.
A. gametes are always haploid whereas spores are diploid
B. gametes can fuse to form a zygote, but spores can develop into independent organisms without first forming a zygote
C. only the formation of gametes contributes to genetic variation
D. gametes are derived directly from sporophytes to form gametophytes
E. gametes are always produced by meiosis whereas spores are always produced by mitosis

49. Which of the following statements reflects an advantage that sexual reproduction likely provides over asexual reproduction?
A. In terms of energetic costs, sexual reproduction is a cheaper strategy than asexual reproduction for generating genetic variation in a population.
B. Although sexual and asexual reproduction both offer opportunities for increasing genetic variation, sexual reproduction is comparatively lower in its energetic costs to the organism.
C. Although energetically more costly than asexual reproduction, sexual reproduction leads to different combinations of alleles that could provide adaptability in a changing environment.
D. Sexual reproduction maintains the same combination of alleles and does not run the risk of losing successful combinations of alleles as is observed to occur in asexually reproducing organisms.
E. Although both reproductive strategies perpetuate the same combination of alleles within individuals in a population, sexual reproduction is energetically less costly than asexual reproduction.

50. Angiogenesis inhibitors have been used as chemotherapeutic drugs to treat certain kinds of cancer. They act by
A. stimulating cytotoxic T cells to kill cancer cells
B. stimulating helper T cells to release interleukins
C. limiting the blood supply to growing tumors
D. destroying the histones in the DNA of cancer cells
E. Both A and B are correct

51. Which term is least related to the others?
A. Her2 receptors
B. breast cancer
C. gene amplification
D. herceptin
E. tumor suppressor gene

52. In mature B cells, different variable (V) and joining (J) segments of DNA combine and are then connected to constant (C) regions before transcription. Why is this observation so important for understanding adaptive immunity?
A. Recombination is an important step in initiating the inflammatory response.
B. Through recombination, the V and C genes get closer together on the chromosome where they are located.
C. Recombination of V and J DNA regions helps to explain the diversity of immunoglobulin molecules that are part of adaptive immunity.
D. Recombination is required for production of a wide array of antigens in the body
E. Recombination of .V and C regions leads to alternate mRNA splicing producing a variety of immunoglobulin molecules for innate immunity

53. If a biochemist discovers a new molecule, which of the following pieces of data would allow her to draw the conclusion that the molecule is a steroid hormone?
I. The molecule is lipid soluble.
II. The molecule is derived from a series of steps beginning with cholesterol.
III. The molecule acts at a target tissue some distance from where it is produced.
IV. The molecule when radioactively labeled is detected in the nuclei of a target tissue.

A. only I and III
B. only II and IV
C. only I, III, and IV
D. only II and III
E. I, II, III, and IV

54. What would be a consequence of a person having Na+ levels in the blood and interstitial fluids that are well below normal?
A. Neurons would all be depolarized.
B. Neurons would not be able to undergo normal action potentials.
C. Action potentials would occur with greater frequency.
D. Neurons would remain refractory following closure of voltage-gated sodium channels.
E. K+ channels would open to compensate for changes in membrane potential.
F.

Answer: D A A B D B C A B D C D A B
Answer:decline in submerged aquatic vegetation

please answer 10-19

Answer: D a b c c
Please answer all questions. I just want to double check my answers. If you can’t answer all, don’t answer at all. I’m doing a check-off of what’s correct/wrong. Thanks.
Answer: A c c b a d c b d

For all questions choose the INCORRECT answer

1) Integral membrane proteins:

a) Osmosis across the lipid bilayer membrane uses protein channels that form open pores connecting the interstitial fluid space with the intracellular fluid compartment

b) A decrease in membrane permeability to a hydrophilic cation could be the result of decreasing the number of open voltage-gated channel proteins

c) Uniport and symport carriers enable the diffusion of glucose from the ECF to the ICF

d) Antiport transporters move substrates in opposite directions with and without the expenditure of energy in the form of ATP

2) Synaptic transmission:

a) Ca++ binding to synaptotagamin is necessary for hormone containing vesicles to alter their conformations to allow vesicle fusion and exocytosis of arginine vasopressin from nerve terminals

b) Electrical synaptic transmission does not require the opening of voltage-gated Ca++ channels while chemical synaptic transmission will not occur unless voltage-gated Ca++ channels are opened

c) !-bungarotoxin is an exogenous agonist that, acting as a ligand, opens ion channels that are necessary and sufficient for the generation of suprathreshold end-plate potentials

d) Neurotransmitters are 1st messenger molecules that bind to integral proteins which function either as ligand-gated ion channels or as G protein-coupled receptors that indirectly open ion channels

3) SA

a) The SA nodal cell action potential(AP) is initiated, in part, by an inward Na+ current, If, and differs from a muscle action potential because the rising phase of the SA nodal cell AP is due to opening of voltage-gated Ca++ channels

b) Epinephrine binding to "#receptors in SA nodal cell membranes results in an increase in the slope of pacemaker potentials, an increase in heart rate and an increase in cardiac contractility

c) ACh binding to muscarinic receptors in SA nodal cell membranes decreases the slope of the graded potential generated by the opening of ‘funny’ voltage-gated channels

d) The resting membrane potential in a ventricular muscle cell is more negative than the resting membrane potential in a SA nodal cell, in part, because ventricular cell membranes do not contain voltage-gated, non-selective cation, HCN channels

4) Action potentials (APs):

a) Saltatory conduction of APs occurs because voltage-gated Na+ channels and voltage-gated K+ channels are not contiguously inserted in the axonal membrane of myelinated fibers, but rather are localized to nodes of Ranvier

b) During the relative refractory period, a suprathreshold depolarizing stimulus can open a sufficient number of voltage-gated Na+ channel activation gates to initiate the depolarization phase of an AP

c) During the depolarization phase of the AP activation gates in voltage-gated K+ channels are closed and simultaneously inactivation gates in voltage-gated Na+ channels are open

d) During the initial period of the repolarization phase, activation gates of Na+ channels and K+ channels are open, and the permeability of the membrane to both ions is increasing

5) Orthostatic hypotension:

a) The precipitous drop in MAP due to gravitational forces on blood is reversed, in part, by increasing heart rate due to increased sympathetic cardiac nerve action potential activity

b) The transient decrease in cardiac output is the result of a transient decrease in stroke volume

c) The reflex increase in MAP following orthostatic hypotension is the result of an increase in cardiac output which is greater than the decrease in peripheral resistance

d) The transient decrease in left ventricular end-diastolic volume due to decreased venous return results in a decrease in carotid sinus baroreceptor action potential discharge activity

6) Renal regulation of Na+ and H2O reabsorption:

a) If plasma osmolarity increased to 400 mOsm (normal is 300 mOsm), plasma levels of AVP would increase and aquaporin channel density would increase in the apical membrane of collecting duct cells

b) When the RAAS system is activated, H2O reabsorption via transepithelial transport in proximal tubules increases if there is a concomitant increase in plasma levels of AVP levels

c) Na+ reabsorption is an active process despite the fact that the initial movement of Na+ from tubular fluid into tubular cells is down a concentration gradient using either a carrier protein or through an open porechannel

d) If an autoimmune disease destroyed AVP receptors in kidney tubular membranes, urine output would increase, in part, because collecting duct epithelial cells manifest a permanent decrease in their permeability to H2O

7) Resting membrane potential (unless otherwise stated assume the [ion] in, out given below apply and that the membrane is selectively permeable to only Na+ and K+ ): [K+]in=150mM [K+]out=5mM [Na+]in=5mM [Na+]out=150mM

a) If one doubled the intracellular concentration of Na+, the resting membrane potential would be more negative

b) The equilibrium potential for K+ would be zero(0) if membrane permeability increased in a cell selectively permeable to Na+

c) If the permeability to Na+ increased 10 fold, and the ratio of PK / PNa remained constant, the resting membrane potential would be less negative

d) In a cell permeable to Na+ and K+, the resting membrane potential = 0 mv for a muscle fiber in rigor

8) Comparison of peptide, catecholamine and steroid hormones:

a) Hydrophobic steroid hormones differ from lipophobic peptide and catecholamine hormones in that for steroids to be transported to distant physiological targets they must be bound to protein carriers

b) Opening of voltage-gated Ca++ channels is necessary for the release of peptide hormones but is not required for the release of steroid hormones

c) The response times for the release of steroid hormones are longer than the response times for the release of catecholamine and peptide hormones because steroid hormones are synthesized on demand while peptide and catecholamine hormones are released on demand

d) Peptide and catecholamine hormones bind to membrane receptors which activate 2nd messenger pathways, while G-protein linked responses to steroid hormones depend upon initial binding to intracellular or nuclear receptors

9) Cellular signaling:

a) In direct gating of an ion channel the 1st messenger binds to a receptor whose opening or closing generates hyperpolarizing or depolarizing potentials that may elicit action potentials

b) The muscarinic receptor in SA nodal cell membranes is G-protein coupled, binds ACh, increases K+ permeability, and upon activation results in decreases in heart rate

c) Amplifier enzymes can be activated by !-subunits or "$-subunits of G proteins in response to binding of 1st messenger ligands to transmembrane receptors

d) If ACh opened a chemically-gated channel that increased PNa and PK, systemic administration of an irreversible antagonist to this receptor would cause muscle relaxation

Answer: A A C B D C A C B A

Please help. By the first explanation I thought if I drop the urine would be ok but I’m still missing one answer
I am guessing then it would be the last two but I’m uncertain
Answer:A single-celled eukaryotic organism excretes digestive waste into the s...
Answer: T F F T T F
Answer:The hormone insulin is recognized by a GPCR on the surface of its targe...
Answer:B. Receptor down-regulation
Answer:Receptor down-regulation
Answer: Receptor down regulation All GPCRs share a similar structure composed ...
Answer: C B B

Biology questions:

Answer the following multiple questions:

1. Essential elements for communication between cells, whether prokaryotic or eukaryotic, involved:

A. Signaling cell

B. Signaling molecule

C. Receptor molecule

D. Responding or receptor cell

E. All of the above

2. The signaling cell releases a---------------, which is recognized by the ----------------on the responding cell.

A. receptor protein, signal transducer

B. signaling molecules, signal transducer

C. signaling molecule,receptor protein

D. Electrical signal, Target molecules

3. The inactivation of many cell signaling pathways involves the removal of phosphates from the activated targets. What is the name of the enzyme that can dephosphorylate proteins?

A. Kinase

B. adenylate cyclase

C. GTPase

D. Peptidase

E. Phosphatase

4. Which step is not part of signaling pathway Signaling between cells involves four steps?

A. receptor activation

B. signal transduction

C. cellular response

D. signal termination

E. Transcription termination

5. Once the receptor is ACTIVATED, it transmits a message to the cell through the cytoplasm in a process called SIGNAL TRANSDUCTION. This message can remain in the cytosol or go to the nucleus.

A. True B. false

6. RESPOND to the signal involve only in gene expression activation

A. True B. false

7. Signaling termination is a critical point in onset of cancer

A. TrueB. False

8. In multicellular organisms, communication signaling only takes place in short distance between the cells.

A. True B. false

9. Endocrine signaling involves:

A. Cell to cell communication

B. Long distance signaling communication

C. Signaling by means of molecules traveling through the bloodstream

D. A and b

E. B and c

10. In human sex hormones are examples of what type of signaling

A. Endocrine

B. Autocrine

C. Merocrine

D. Paracrine

11. In paracrine signaling what the average distance the signaling molecules will travel

A. Only one cell away

B. 10 cells diameter

C. 20 cells diameter

D. 1000 cells diameter

12. In paracrine signaling, the signal is usually a ------------------------such as -------------------

A. insoluble molecules, actin filaments

B. soluble molecule, growth hormones

C. insoluble molecules, estrogen

D. soluble molecules androgen

13. Autocrine signaling are especially important to multicellular organisms during embryonic development

A. True B. false

14. Paracrine signaling are especially important to multicellular organisms during embryonic development.

A. True B. false

15. There would be no signaling processes in the absence of signaling molecules

A. TrueB. False

16. Which of the following statements about mammalian skin is incorrect?

A. The epidermis is an outer layer that provides a water-resistant, protective barrier.

B. The dermis is the layer below the epidermis containing connective tissue, blood vessels, and nerve endings that provides nutrients to the epidermis and a cushion layer for the body.

C. Epithelial cells in the epidermis are primarily composed of keratinocytes that protect underlying tissue.

D. A specialized form of extracellular matrix, called the basal lamina, underlies the dermis and separates it from tissues below.

E. Fibroblasts in the dermis produce extracellular matrix proteins to make the dermis strong and flexible.

17. What would happen to a cell that depends on flagellar movement if it had no actin?

A. The cell would not be able to move because the cilia would also be affected.

B. The cell would not be able to move.

C. Nothing; the cell would still be able to move.

D. The cell would move by cilia and not flagella.

18. Which is not an example of a motor protein?

A. myosin

B. kinesin

C. venosin

D. dynein

19. Why are the ends of microfilaments and microtubules called “plus ends” and “minus ends”?

A. Because monomers are added more quickly to one end (the “plus end”) than they are to the other end (the “minus end”).

B. Because polymerization occurs at one end (the “plus end”) and depolymerization occurs at the other end (the “minus end”).

C. Because monomers can be added to one end only (the “plus end”), and can only be removed from the other end (the “minus end”).

D. Because the actin and tubulin monomers that make up microfilaments and microtubules have evolved more rapidly than most other proteins.

20. Which one of the following statements about intracellular transport is true?

A. Kinesin and myosin move substances along microtubules.

B. Kinesin and dynein move substances along microfilaments.

C. Myosin and dynein move substances along microfilaments.

D. Myosin moves substances along microfilaments.

For each structure described below, indicate the cytoskeletal element that it best characterizes. Cytoskeletal elements may be used multiple times or not at all. Questions 21-26

A. microtubules B. microfilaments C. intermediate filaments

21. the cytoskeletal elements with the largest diameter

22. the cytoskeletal elements with the smallest diameter

23. double helices of polymerized actin proteins

24. strong fibers of more than a hundred different types

25. hollow tube-like structures made of polymerized tubulin protein dimers

26. proteins in the nucleus that give shape and support to the nuclear envelope

27. Which cell adhesion molecule is particularly good at cell to cell adhesion

A. cadherins

B. integrins

C. myosin

D. actin

28. Which type of cell junction prevents the movement of substances through the space between cells?

A. tight junctions

B. adherens junctions

C. desmosomes

D. hemidesmosomes

E. gap junctions

29. Which one of the following statements about integrins is correct?

A. Integrins indirectly connect microfilaments with the extracellular matrix.

B. There is a single type of integrin, capable of binding to multiple types of extracellular matrix proteins.

C. Integrins are the primary cell adhesion molecule in a desmosome.

D. Adjacent integrins create channels referred to as gap junctions.

30. The dermis of mammalian skin, including that of humans, contains a large amount of extracellular matrix proteins, including collagen and elastin. As a person ages, the amount of elastin in the dermis declines. Which of the following cell types is likely to be the cause of this change in the dermis of the skin?

A. keratinocytes

B. fibroblasts

C. melanocytes

D. epidermal cells

31. The extracellular matrix can influence: A. cell movement.

B. cell shape.

C. gene expression.

D. All of these choices are correct.

36. A kinase is an enzyme that -------------a phosphate group and Phosphatases is an enzyme that --------a phosphate group.

A. Phosphorylate, add

B. add, remove

C. remove, add

D. digest, remove

37. In regards to following statements:

Statement 1: Many cancers arise when something goes wrong with the way a cell responds to a signal that leads to cell division or, in some cases, when a cell behaves as if it has received a signal for cell division when in fact it hasn’t.

Statement 2: Problems with cell signaling that can lead to cancer can take place at just about every step in the cell-signaling process.

A. Both are true B. Both are not true C. 1 Is true but 2 is not D. 1 is not true but 2 is true

38. The extracellular matrix in animals:

A. is located exclusively in muscle tissue.

B. is formed by many types of cells, primarily fibroblasts, on their cell surfaces.

C. is a meshwork of insoluble fibrous proteins, primarily collagens that assemble in a double helix.

D. differs from one tissue to the next, affecting the expression of genes in the cells that it surrounds.

E. is attached to cells by gap junctions.

39. A collection of cells that work together to perform a specific function called.

A. Organ B. Tissue C. System D. species

40. The shape of cells is determined and maintained by structural protein networks in the cytoplasm, called

A. cytoskeleton.

B. Signaling pathway

C. Signaling molecules

D. polysaccharide molecules

45. The cells make up the epidermis layer of skin are called

A. Fibroblasts

B. Keratinocytes

C. Connective tissue

D. Cytoskeleton

46. The structural integrity of a tissue or organ depends on:

A. Cells adhesion

B. Cells adhere to extracellular matrix

C. Cells average size

D. All of above

E. A and B

47. Microtubule are made of protein subunits called

A. Actin monomer B. Cell junction protein

C. ? tubulin and ? tubulin D. Integrin

48. The function of tight junctions is not to anchor the cells together, but instead to prevent passage of materials in between cells.

A. True B. false

49. The extracellular matrix is an insoluble meshwork composed of-------- and -----------

A. lipid, protein

B. Carbohydrate, lipid

C. Proteins, polysaccharides.

D. Cellulose, lipids

50. Metastatic cancer tumor cells pass the blood vessels barrier by mean of:

A. Carbohydrate in extracellular matrix

B. Protein (integrin) of extracellular matrix

C. Will not pass the blood vessels barrier.

Answer: C A A D B A B B A D
Answer:stage 1 – the cancer is small and hasn't spread anywhere else. stage 2 ...
Answer:3)Micrometastases remain dormant for many years.
Answer: Step-by-step explanation:Phylogenetic analysis indicates that multiple...
evolution

Answer:Creationism and Creation Science. The belief in the account of the crea...

Answer:Adaptive landscapes hold a central and special position in evolutionary...

Answer:An evolutionary constraint helps explain why something didn't or doesn'...
Answer: Step-by-step explanation: Neo-Darwinism is the term popularly used, ev...
Answer:The neutral theory holds that most variation at the molecular level doe...
Answer: Category BStep-by-step explanation:category B, indicating no evidence ...

Weekly leaderboard

Start filling in the gaps now
Log in