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BIOL2000 Lecture Notes - Lecture 5: Prentice Hall, Carbonyl Group, Alpha Helix

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maroonbear404
15 Feb 2016
School
Boston College
Department
Biology
Course
BIOL2000
Professor
Thomas Chiles

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Document Summary

Sugars and other carbs are variable in structure. Monosaccharides are monomers that polymerize to form polysaccharides through different glycosidic linkages. Carbs perform a variety of functions, from energy storage to formation of structures. Contain a carbonyl and several hydroxyl functional groups: carbonyl: reacts to make the carb a large molecule, hydroxyl: makes the carbs soluble in water. Difference between aldehydes and ketones is the location of the carbonyl group. Vary in structure through: placement of carbonyl group, different # of carbons, hydroxyl group arrangements, alternative ring forms (alpha or beta) Aldehyde sugar (aldose0: carbonyl is at the end of the molecule. Ketone sugar (ketose): carbonyl is in the middle of carbon chain. Varies between: three triose, five pentose, six hexose. Directionality: carbon atoms are numbered starting at the end closest to the carbonyl group. Same chemical formula but different structures = different. Hydroxyl groups are what cause the condensation reactions when forming linkages between monosaccharides.

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Related Questions

1) What is the difference between maltose and amylose (starch)?
Select one:
a. Maltose is joined by 1-4 glycosidic linkages, while amylose is joined by 1-6 glycosidic linkages.
b. Maltose is made of glucose in the alpha form, while amylose is made of glucose in the beta form.
c. Maltose is composed of glucose monomers, while amylose is composed of fructose monomers.
d. Maltose is a disaccharide, while amylose is a polysaccharide.
2) What does the “1-4” in “1-4 glycosidic linkage” mean?
Select one:
a. Each branch of the chain is followed by four monosaccharides.
b. A one-carbon monosaccharide is connected to a four-carbon monosaccharide.
c. The first carbon on one monosaccharide is connected to the fourth carbon on the next monosaccharide.
d. Each monosaccharide is connected to four other monosaccharides.

3)

What is the difference between the sugar group in DNA and the sugar group in RNA?

Select one:

a. The sugar group in DNA is a hexose, while the sugar group in RNA is a pentose.

b. The sugar group in DNA has one less hydroxyl group (–OH) than the sugar group in RNA.

c. The sugar group in DNA is a purine, while the sugar group in RNA is a pyrimidine.

d. The sugar group in DNA contains one less carbonyl group (double-bonded oxygen atom) than the sugar group in RNA.

Multiple Choice

1. Which of the following describes lipids?

a source of nutrients for organisms 


energy-storage molecules 


molecules having structural role in membranes 


molecules that are part of hormones and pigments 


all of the above 


2. Molecules bearing both polar and nonpolar groups are said to be which of the following?

a. hydrophilic


b. amphipathic

c. hydrophobic

d. polyfunctional

3. By definition, carbohydrates contain which elements?

carbon and hydrogen 


carbon, hydrogen, and nitrogen 


carbon, hydrogen, and oxygen 


carbon and oxygen 


4. Monosaccharides may link together to form polysaccharides by forming which type of bond?

a. hydrogen

b. peptide


c. ionic


d. glycosidic

5. Which of the following is the name for molecules whose structures are nonsuperimposable mirror images?

structural isomers 


monomers 


polymers 


enantiomers 


Which of the following is an organism that obtains its energy from the transfer of electrons originating from chemical compounds and its carbon from an inorganic source?

a. chemoautotroph

b. chemoheterotroph

c. photoheterotroph

d. photoautotroph

7. A cell might perform anaerobic respiration for which of the following reasons?

It lacks glucose for degradation. 


It lacks the transition reaction to convert 
pyruvate to acetyl-CoA. 


It lacks Krebs cycle enzymes for processing 
acetyl-CoA to CO2. 


It lacks a cytochrome oxidase for passing 
electrons to oxygen. 


8. Which of the following is not an electron carrier within an electron transport system?

a. flavoprotein

b. ATP synthase

c. ubiquinone

d. cytochrome oxidase

9. Which of the following is the purpose of fermentation?

a. to make ATP

b. to make carbon molecule intermediates for anabolism

c. to make NADH

d. to make NAD+

10. Which of the following processes produces hydrogen sulfide?

anoxygenic photosynthesis 


oxygenic photosynthesis 


anaerobic respiration 


chemoautrophy 


11. In which growth phase would you observe the most endospores in a Bacillus cell culture?

death phase 


lag phase 


log phase 


log, lag, and death phases would all have roughly 
the same number of endospores. 


12. Which of the following is the best definition of generation time in a bacterium?

a. the length of time it takes to reach the log phase 


b. the length of time it takes for a population of 
cells to double 


c. the time it takes to reach stationary phase 


the length of time of the exponential phase 


If a culture starts with 50 cells, how many cells will be present after five generations with no cell death?

a. 200

b. 400

c. 1600

d. 3200

14. During which phase would penicillin, an antibiotic that inhibits cell-wall synthesis, be most effective?

death phase 


lag phase 


log phase 


stationary phase 


15. Pseudomonas aeruginosa is a common pathogen that infects the airways of patients with cystic fibrosis. It does not grow in the absence of oxygen. The bacterium is probably which of the following?

an aerotolerant anaerobe 


an obligate aerobe 


an obligate anaerobe 


a facultative anaerobe 


16. Which of the following refers to photosynthesis performed by bacteria with the use of water as the donor of electrons?

a. oxygenic


b. anoxygenic

c. heterotrophic

d. phototrophic

17. Which term best describes the relationship between pathogenic bacteria and humans?
A. amensalism

B. commensalism

C. parasitism

D. predation

18. Which describes bacteria that require low concentrations of oxygen to survive (less than that in the current atmosphere)?

A. facultative anaerobes

B. microaerophiles

C. obligate aerobes

D. obligate anaerobes

19. Cyanobacteria produce which of the following?

A. hydrogen sulfide gas
B. large quantities of ammonia

C. oxygen*
D. sulfuric acid

20.How do Archaea differ from Bacteria?

A. Archaea are found exclusively in extreme habitats.
B. Archaea have ether linkages in their cell membranes.*

C. Archaea have peptidoglycan cell walls.

D. Archaea lack a nucleus.

1. In addition to identifying the genetic material, the experiments of Avery, MacLeod, and McCarty with different strains of Streptococcus pneumoniae demonstrated that
DNA is a double helix.
DNA may be taken up by bacterial cells and be active.
DNA is present in bacteriophage T2.
eukaryotic cells may be genetically transformed.
DNA binds to the cell wall of the bacterium.
2. In order to show that DNA in cell extracts is responsible for genetic transformation in Streptococcus pneumoniae, important corroborating evidence should indicate that _______ also destroy transforming activity.
temperatures high enough to kill cells
enzymes that hydrolyze proteins
enzymes that hydrolyze DNA
enzymes that hydrolyze polysaccharides
enzymes that hydrolyze RNA
3. Based on what you have learned about the experiments conducted by Griffith and Avery and colleagues with bacteria, which of the following would result in transformation of living R cells?
Pure RNA from S cells
Cell-membrane extracts from S cells
A mixture of pure RNA and protein from S cells
Cell-free extracts from S cells
Pure protein from S cells
4. A-T base pairs in a DNA double helix
form three hydrogen bonds with each other.
are more heat-stable than G-C base pairs.
are of a substantially different length than G-C base pairs.
are not accessible to DNA binding proteins.
are chemically distinct from G-C base pairs.
5. If 23 percent of the bases in a sample of double-stranded DNA are adenine, what percentage of the bases are uracil?
27
50
0
73
23
6. The uniform diameter of the DNA structure provides evidence for
antiparallel DNA strands.
a right-handed helix.
a double-stranded helix.
3′ end phosphorylation.
purine–pyrimidine pairing.
7. If a sequence of one strand of DNA is 5′-TGACTATC-3′, what is the complementary strand?
5′-ACTGATAG-3′
3′-TGACTATC-5′
3′-ACTGATAG-5′
3′-ACTGATAG-3′
5′-TGACTATC-3′
8. What structural aspect of the DNA facilitates dissociation of the two DNA strands for replication?
3′ end phosphorylation
Purine–pyrimidine pairing
Antiparallel DNA strands
Covalent bonds between sugars and phosphate groups
Hydrogen bonding between paired bases
9. If the Meselson–Stahl density gradient experiment had resulted in two bands of DNA molecules after only one round of replication, one containing only 15N and the second only 14N, this result would have indicated that replication was
unidirectional.
dispersive.
conservative.
bidirectional.

semiconservative.
10. The nucleoside analogue acyclovir, which is used to treat herpes simplex virus (HSV) infections, lacks a 3′ hydroxyl group (–OH). Predict what will happen if the host cell DNA polymerase incorporates a molecule of acyclovir into an elongating strand of HSV DNA.
The replication complex will no longer bind to origins of replication.
The DNA polymerase will only incorporate acyclovir molecules.
Acyclovir will bind single-strand binding proteins.
DNA polymerase will not be able to link a successive nucleotide.
Acyclovir will block the activity of the DNA helicase.
11. Which of the following does not demonstrate the stability of the DNA double helix?
Single-strand binding proteins are required to keep the strands apart.
Paired bases form hydrogen bonds.
High temperatures are required to denature it.
DNA synthesis requires energy.
DNA helicases require ATP.
12. What effect would a primase inhibitor have on DNA replication?
DNA polymerase would not be able to add bases to the DNA.
Primase would be blocked from joining the DNA replication complex.
Primase would not be able to provide primers for DNA polymerases.
DNA polymerase would not be able to use DNA as a template.
There would be no effect on DNA replication.
13. To replicate their DNA in a timely manner, most eukaryotic chromosomes
normally have uncoiled DNA.
have multiple origins of replication.
contain linear molecules of single-stranded DNA.
have two replication forks that move in the same direction.
are composed entirely of DNA.
14. Which statement about DNA replication is false?
Okazaki fragments are synthesized as parts of the leading strand.
Error rates for DNA replication are reduced by proofreading of the DNA polymerase.
The sliding clamp increases the rate of DNA synthesis.
Replication forks represent areas of active DNA synthesis on the chromosomes.
Ligases and polymerases function in the vicinity of replication forks.
15. In many eukaryotes, there are repetitive sequences called telomeres at the ends of chromosomes. After successive rounds of DNA replication, the _______ strand becomes shorter. In some cells, an enzyme called _______ repairs the shortened strand.
leading; telomerase
lagging; telomerase
lagging; DNA polymerase I
leading; DNA polymerase I
leading; replicase
16. A researcher studies normal human fibroblast cells. They can be maintained in culture but die off after about 30 cell generations. Unexpectedly, a colony of cells continues to survive and divide past 30 generations. Which scenario is most likely true for these cells?
DNA polymerase is constantly active.
Primase is able to extend the telomeres.
The mismatch repair system is extra efficient.
The telomerase gene is being expressed.
The cells do not need the ends of their chromosomes.
17. If DNA polymerase III introduces an incorrect nucleotide, what is the first corrective action made by the DNA repair system?
The replication complex excises the incorrect nucleotide.
The excision repair proteins remove the incorrect nucleotide.
The mismatch repair system scans for base-pairing mismatches.
There is no correction, because nucleotide errors by DNA polymerases are not repaired.
DNA ligase connects the correct nucleotide.
18. Choose the correct order of the following four events in the excision repair of DNA:
(1) Base-paired DNA is made complementary to the template.
(2) Damaged bases are recognized.
(3) DNA ligase seals the new strand to existing DNA.
(4) Part of a single strand is excised.
1, 2, 3, 4
2, 1, 3, 4
3, 4, 2, 1
2, 4, 1, 3
4, 2, 3, 1
19. Six complete cycles of PCR should result in a _______-fold increase in the amount of DNA.
64
32
12
128
6
20. When double-stranded DNA is heated to temperatures above 90°C, it denatures. Denaturation is a process that
breaks covalent bonds.
hydrolyzes DNA.
separates double-stranded DNA into two single strands.
causes new hydrogen bonds to form.
irreversibly destroys the double helical structure.