BIO 1130 Lecture Notes - Lecture 4: Heterozygote Advantage, Synaptonemal Complex, Eukaryote

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If 2 alleles are different, the dominant allele is dominant over the recessive allele, and its expression will dominate (unless it is incomplete dominance) Represents the number of a particular allele present in the population compared to the total amount. Represented from a number of 0 to 1. Used to describe structure of a gene pool. When 2 difference species are created as a result of physical separation in the environment from each other. One of two or more versions of a gene. 2 or ore complete set s of chromosomes from different parent specie. 2 different organisms release their gametes (n) forming a interspecific species zygote (2n) That zygote undergoes failed meiosis producing 2n gametes. They form fertilize each other to form a tetraploid cell (4n) viable for plants. Signal word in cladistics demonstrating derived characters within a group. Over time, a trait will change into something else, emerge, or disappear.

Related Questions

1). Thyroid hormone (TH) has been identified as one of the factors promoting phenotype development in the Mexican axolotl salamander. Which of the following statements regarding the impact of TH is FALSE?

A). Axolotls maturing in water with high concentration of TH (thyroxine; T4) metamorphose into a terrestrial form.

B). A genome-wide scan of both the axolotl and its sister species found a large reduction in the number of mRNA transcripts that regulate the production of TH.

C). Adding TH (thyroxine; T4) to the water in which axolotl individuals are reared causes them to remain in a larval stage.

D). Most salamander species produce a burst of TH when they move from water to land.

2).What would be an appropriate evolutionary explanation of the fact that the ordering of some homeotic genes (such as Hox genes) on vertebrate chromosomes parallels the ordering of homeotic genes on fruit fly chromosomes?

A). The similarity is a coincidence, not documented in other invertebrates and largely a result of random mutations.

B). Homeotic genes show that insects and vertebrates are closer relatives than the traditional classification system indicates.

C). Homeotic genes of different animal lineages might be ordered in a similar fashion, yet their sequences are completely different.

D). The similar ordering of homeotic genes in animals, both vertebrate and insect, is due to ancient homology.

3). Which of the following correctly defines "homeotic genes"?

A). Homeotic genes encode proteins that control the cellular environment in a differentiated cell tissue.

B). Homeotic genes are DNA sequences that turn off, but not on, the expression of other genes and are controlled by "master-switch" genes.

C). Homeotic genes are "master-switch" genes that control other genes in a set sequence and thereby affect cell size, shape, division, and the positioning of the cells within the organism.

D). Homeotic genes are DNA sequences that turn on, but not off, the expression of other genes and are controlled by "master-switch" genes.

4). Which of the following is NOT considered a type of heterochrony (change in the rate and timing of development)?

A). hypermorphosis

B). acceleration

C). neoteny

D). ontogeny

5). How does the dominance theory explain why the heterogametic sex is at a disadvantage in Haldane's rule?

A). Beneficial dominant alleles will never be fully expressed in hybrids as they only carry one copy of the sex chromosome that carries the allele.

B). If a dominant allele has a negative effect on the fitness of hybrids, it will always be expressed in the heterogametic hybrids that possess that allele because they only need one copy of the respective sex chromosome.

C). If a recessive allele linked to a sex chromosome has a negative effect on the fitness of hybrids, that allele will always be expressed in the heterogametic hybrids that possess that allele because they only have one copy of the sex chromosome that carries the allele.

D). If a recessive allele linked to a sex chromosome has a positive effect on the fitness of hybrids, that allele will never be expressed in the heterogametic hybrids that possess that allele because they only have one copy of the sex chromosome that carries the allele.

6). In a hypothetical flowering plant species, one population evolves a different response to environmental stimuli and begins to bloom significantly later in the season than nearby populations. What type of reproductive isolating mechanism would this be?

A). hybrid sterility

B). postzygotic

C). prezygotic

D). gametic incompatibility

7). In a study of red spruce trees and black spruce trees, scientists found that the red spruce was living in a smaller geographic area and had much less genetic variation than the black spruce. They proposed that the red spruce might have arisen from a southern population of black spruce, which became geographically isolated from other black spruce populations at some point during the Pleistocene glaciations. What is this an example of?

A). allopatric speciation with the vicariance model

B). sympatric speciation

C). allopatric speciation with the peripheral isolate model

D). sympatric speciation with the ring species model

8). Which of the following defines Haldane's rule and its predictions?

A). If among hybrid offspring one sex is absent, rare, or sterile, that sex is always male.

B). If among hybrid offspring one sex is absent, rare, or sterile, that sex is always female.

C). If among hybrid offspring one sex is absent, rare, or sterile, that sex is heterogametic (has two different sex chromosomes).

D). If among hybrid offspring one sex is absent, rare, or sterile, that sex is homogametic (has two of the same sex chromosomes).

8.) Which of the following statements best explains secondary reinforcement?

A). If the reproductive isolating mechanisms that developed during the geographic isolation are strong but the hybrids have higher fitness than the parent species, then the speciation process will cease.

B). If the reproductive isolating mechanisms that developed during the geographic isolation are somewhat weak but the hybrids between two populations have lower fitness, then the speciation process may continue.

C). If the reproductive isolating mechanisms that developed during the geographic isolation are sufficiently weak as to allow free interbreeding across reunited populations, then the speciation process will halt and a single species will remain.

D). When geographic isolation comes to an end, two populations always complete the divergence process and become separate species.

ceruleanzebra430

___1. Nationally, the most common cause of Down Syndrome is
a. nondisjunction of Chromosome 21 during meiosis
b. translocation of Chromosome 21 onto another chromosome
c. inversion of a large section of Chromosome 21
d. deletion of the Down Syndrome gene
___2. In humans, sex is determined by
a. The presence or absence of the Y chromosome
b. The ratio of X chromosomes to sets of autosomes
c. The temperature during fetal development
d. Which parent is stronger at the time of conception
___3. A translocation is
a. a chromosomal abnormality in which a piece of one chromosome breaks off and attaches to a different chromosome
b. an abnormality in which the chromosomes are translocated out of the nucleus
c. a condition in which the chromosome has broken in two places and come back together with the middle segment backward
d. an abnormality in which there is an extra copy of one chromosome
___ 4. In snapdragons, a red-flowered plant crossed with a white-flowered plant produces all pink-flowered offspring. But crossing two pink-flowered plants produces red, pink, and white in a 1:2:1 ratio. This is a good example of
a. Incomplete dominance
b. Dominance of the red allele over the white allele
c. Lethal effects of the pink allele
d. Sex-linkage of the flower-color alleles
___ 5. If a person with type AB blood marries a person with Type O blood, what blood types are possible in their children? (Assume this trait is a single-gene trait, not complicated by interaction with other genes).
a. A, B, AB, or O
b. A or B only
c. AB or O only
d. AB only 2
___6. In what phase of meiosis are haploid nuclei first formed? a. Anaphase I b. Metaphase II c. Telophase II d. Metaphase I e. Telophase I
___7. What is the phenotype of a heterozygous tall pea plant? a. tall b. Tt c. TT d. tt e. dominant
___ 8. If genes A and B are far apart on a chromosome, and A and C are close together, which of the following observations is expected?
a. Crossing over will occur more often between A and C than between A and B
b. Crossing over will occur at equal frequencies between A and C, and between A and B
c. Crossing over will occur more often between A and B than between A and C
___9. Sometimes an organismâs genotype for one gene masks the effect of a different gene. This phenomenon is called
a. Dominance
b. Incomplete dominance
c. Co-dominance
d. Epistasis
e. Variable expressivity
___10. The dominant allele of a gene is
a. The one that is expressed most often in a population
b. The one that is expressed most often in any particular cross
c. The one that is expressed in an individual that has two different alleles
d. The one that is most healthy to have, that gives the greatest fitness
___11. In human cells, DNA replication occurs
a. In S phase of interphase
b. In G1 phase of interphase
c. In G2 phase of interphase
d. In prophase of mitosis
e. Whenever the cell needs to read the DNA to make proteins
___ 12. A process in which recipient cells take up genes from DNA molecules floating free in the surrounding medium is called
a. conjugation
b. specialized transduction
c. generalized transduction
d. transformation 3
___ 13. Most calico cats are female. However, a few rare males are observed. What is the genotype of a male calico cat?
a. X BX 0
b. X OY
c. X BY
d. X BYY
e. X BX OY
___ 14. A type of red-green color-blindness is a sex-linked (X-linked) recessive trait in humans. Can a woman have this type of color-blindness?
a. Yes, a woman could be color-blind if her mother and father were both heterozygous.
b. Yes, a woman could be color-blind but only if she has an abnormal number of sex chromosomes.
c. No, women can't show sex-linked traits because they lack a Y chromosome.
d. No, women can't show sex-linked traits because they have two X chromosomes.
e. Yes, a woman could be color-blind if her father was color-blind and her mother was a carrier (heterozygous).

If an organismâs diploid chromosome number is 18, how many different possible combinations of homologous chromosomes lining up during meiosis exist for the eggs or sperm produced by that organism?

	A.	512
	B.	9
	C.	18
	D.	128
	E.	36

At the end of metaphase I, _______________ separate.

	A.	sister chromatids
	B.	germ cells
	C.	homologous chromosomes
	D.	haploid chromatids
	E.	centrioles

Mendel observed that dominant traits

	A.	are seen in all of the F1 hybrid pea plants in his experiments.
	B.	are expressed in all plants.
	C.	were absent in the F1 generation of pea plants that he used in his experiments.
	D.	were the only traits seen in the F2 generation of pea plants in his experiments.
	E.	are only expressed in hybrids.

Cytokinesis in plant cells differs from cytokinesis in animal cells because

	A.	there is no difference.
	B.	in plant cells, the cell plate must also divide into two parts.
	C.	the contractile protein, actin, is important only in plant cells.
	D.	plant cells have a rigid cell wall.
	E.	a contractile ring forms only in plant cells.

Sickle cell anemia is an example of what type of inheritance?

	A.	complete dominance
	B.	incomplete dominance
	C.	codominance
	D.	multiple alleles
	E.	recessive dominance

Which of the following statements is true:

	A.	The dominant allele is masked in homozygous dominant individuals.
	B.	With recessive genetic disorders, if both parents are carriers, the offspring will all be affected.
	C.	In carriers, the recessive allele causes an intermediate phenotype.
	D.	In recessive genetic disorders, the mother and/or father of an affected individual must also be affected.
	E.	With dominant genetic disorders, the mother and/or father of an affected individual must also be affected.

Skin cancers typically develop in the

	A.	upper layers of the epidermis.
	B.	lower layers of the dermis.
	C.	subcutaneous layer.
	D.	lower layers of the epidermis.
	E.	upper layers of the dermis.

Duchenne muscular dystrophy (MD) is inherited from an X-linked recessive allele. What is the probability that a son with Duchenne MD inherited this disease from his biological father?

	A.	1/2
	B.	0
	C.	1/16
	D.	1/4
	E.	1/8

The genetic makeup of a particular trait in an individual is its

	A.	genotype.
	B.	heterozygosity.
	C.	phenotype.
	D.	filial.
	E.	dominance.

What structure holds the sister chromatids to the spindle fibers?

	A.	chromatin
	B.	kinetochore
	C.	MPF
	D.	centromere
	E.	cyclin

If you view a cell in which the genetic material is beginning to be visible as separate bodies, and the nucleus has disappeared from view, you may surmise that the cells is in

	A.	telophase.
	B.	anaphase.
	C.	interphase.
	D.	metaphase.
	E.	prophase.

Gregor Mendel was successful in his analysis of the genetics of pea plants because

	A.	he examined and analyzed both the F1 and F2 generations.
	B.	he studied the parental plants to determine their differences.
	C.	he decided to only look at his results in an objective manner.
	D.	he studied a trait that had a strange inheritance pattern.
	E.	pea plants have genetics different from other organisms.

Tall corn plants (T) are dominant to dwarf plants (tt). Solid green leaves (G) are dominant to leaves with a white tip (gg). A cross between two corn plants yielded the following phenotypes: 51 tall plants with a white tip on their leaves; 43 dwarf plants with solid leaves; 48 dwarf plants with white tips on their leaves; 45 tall plants with solid leaves. What are the genotypes of the parents that produced these plants?

	A.	None of the above
	B.	TtGg x Ttgg
	C.	ttGG x TTgg
	D.	TtGg x TtGg
	E.	TtGg x ttgg

In humans, a gene that has been identified as causing a type of skin cancer is the

	A.	superwoman echidna.
	B.	mutant superman.
	C.	sonic hedgehog.
	D.	mutant mole rat.
	E.	superhero aardvark.

The segregation principle states that in sexually reproducing diploid organisms the two copies of each gene

	A.	segregate from each other during meiosis.
	B.	must always be the same allele.
	C.	separate from each other during mitosis.
	D.	will both wind up in either the sperm or egg.
	E.	move together as a unit during meiosis.

In what phases is the genetic material in the cell correctly referred to as chromatids?

	A.	metaphase and telophase
	B.	anaphase and metaphase
	C.	interphase and telophase
	D.	interphase and prophase
	E.	metaphase and prophase

Consider two traits for an organism, determined by two genes, each of which is governed by at least two alleles. In the case of a dihybrid individual, the gametes formed will be of either the parental type or the recombinant type. Recombinant type gametes are formed because of

	A.	the principle of dihybrids.
	B.	multiple alleles.
	C.	heterozygosity.
	D.	incomplete dominance.
	E.	independent assortment.

An allele is

	A.	an alternate form of a gene.
	B.	always recessive.
	C.	the main factor determining a trait.
	D.	always one of a pair.
	E.	the dominant form of a gene.

After the DNA is replicated, and it condenses in prophase, two identical rods of DNA are seen. These are

	A.	spindle fibers.
	B.	kinetochores.
	C.	chromatids.
	D.	chromatin.
	E.	centromeres.

Special cells found in the gonads that give rise to gametes upon division are called

	A.	egg cells.
	B.	somatic cells.
	C.	germ cells.
	D.	stem cells.
	E.	basal cells.

BIO 1130 Lecture Notes - Lecture 4: Heterozygote Advantage, Synaptonemal Complex, Eukaryote

BIO 1130 Full Course Notes

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