Monday, December 1, 2008

Unit 3 Test Review!

Hey girls, today in class we just took a chapter 15 quiz and started our lab. Tomorrow, however, we have a HUGE test! So study hard and use the blog to help!

Chapter 12

Density dependent inhibition:
The phenomenon observed in normal animal cells that causes them to stop dividing when they come into contact with one another.

Maturation-promoting factor (M-phase-promoting factor); a protein complex required for a cell to progress from late interphase to mitosis. The active form consists of cyclin and a protein kinase.

A regulatory protein whose concentration fluctuates cyclically.

Cell plate:
A double membrane across the midline of a dividing plant cell, between which the new cell wall forms during cytokinesis.

The process of cytokinesis in animal cells, characterized by pinching of the plasma membrane; specifically, the succession of rapid cell divisions without growth during early embryonic development that converts the zygote into a ball of cells.

A specialized region on the centromere that links each sister chromatid to the mitotic spindle.

Material present in the cytoplasm of all eukaryotic cells, important during cell division; the microtubule-organizing center.

The division of the cytoplasm to form two separate daughter cells immediately after mitosis.

The centralized region joining two sister chromatids

Sister chromatids:
Replicated forms of a chromosome joined together by the centromere and eventually separated during mitosis or meiosis II.

A haploid cell, such as an egg or sperm. Gametes unite during sexual reproduction to produce a diploid zygote.


centro- the center
mito- a thread
meta- between
telos- an end
soma- body
pro- before
meio- less
mal- bad or evil
inter- between
gen- produce
gamet-a wife or husband

1. Increases in the enzymatic activity of some protein kinases important for the regulation of the cell cycle are due to

a) kinase synthesis by ribosomes.

b) activation of inactive kinases by binding to cyclins.

c) conversion of inactive cyclins to active kinases by means of phosphorylation.

d) cleavage of the inactive kinase molecules by cytoplasmic proteases.

e) a decline in external growth factors to a concentration below the inhibitory threshold.

2 . Through a microscope, you can see a cell plate beginning to develop across the middle of the cell and nuclei re-forming on either side of the cell plate. This cell is most likely

a) an animal cell in the process of cytokinesis.

b) a plant cell in the process of cytokinesis.

c) an animal cell in the S phase of the cell cycle.

d) a bacterial cell dividing.

e) a plant cell in metaphase.

3 . Vinblastine is a standard chemotherapeutic drug used to treat cancer. Because it interferes with the assembly of microtubules, its effectiveness must be related to

a)disruption of mitotic spindle formation.

b) inhibition of regulatory protein phosphorylation.

c) suppression of cyclin production.

d) myosin denaturation and inhibition of cleavage furrow formation.

e) inhibition of DNA synthesis.

4 . A particular cell has half as much DNA as some of the other cells in a mitotically active tissue. The cell in question is most likely in

a) G1.

b) G2.

c) prophase.

d) metaphase.

e) anaphase.

5 . One difference between a cancer cell and a normal cell is that

a) the cancer cell is unable to synthesize DNA.

b) the cell cycle of the cancer cell is arrested at the S phase.

c) cancer cells continue to divide even when they are tightly packed together.

d) cancer cells cannot function properly because they suffer from density-dependent inhibition.

e) cancer cells are always in the M phase of the cell cycle.

6 . The decline of MPF activity at the end of mitosis is caused by

a) the destruction of the protein kinase (Cdk).

b) decreased synthesis of cyclin.

c) the degradation of cyclin.

d) synthesis of DNA.

e) an increase in the cell's volume-to-genome ratio.

Answers: 1. b, 2. a, 3. a, 4. a, 5. c, 6. c

Chapter 13

The transmission of traits from one generation to the next.

In organisms undergoing alternation of generations, the multicellular haploid form that mitotically produces haploid gametes that unite and grow into the sporophyte generation.

In the life cycle of a plant or alga undergoing alternation of generations, a meiotically produced haploid cell that divides mitotically, generating a multicellular individual, the gametophyte, without fusing with another cell.

Differences between members of the same species.

The pairing of replicated homologous chromosomes during prophase I of meiosis.

In organisms undergoing alternation of generations, the multicellular diploid form that results from a union of gametes and that meiotically produces haploid spores that grow into the gametophyte generation.

A paired set of homologous chromosomes, each composed of two sister chromatids. Tetrads form during prophase I of meiosis.

A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA (or RNA, in some viruses).

A two-stage type of cell division in sexually reproducing organisms that results in cells with half the chromosome number of the original cell.

(plural, chiasmata) The X-shaped, microscopically visible region representing homologous chromatids that have exchanged genetic material through crossing over during meiosis.

Crossing over:
The reciprocal exchange of genetic material between nonsister chromatids during prophase I of meiosis.

Homologous structure:
Structures in different species that are similar because of common ancestry.

(plural, loci) A specific place along the length of a chromosome where a given gene is located.

Diploid cell:
A cell containing two sets of chromosomes (2n), one set inherited from each parent.

A display of the chromosome pairs of a cell arranged by size and shape.Clone:
(1) A lineage of genetically identical individuals or cells. (2) In popular usage, a single individual organism that is genetically identical to another individual. (3) As a verb, to make one or more genetic replicas of an individual or cell. See also gene cloning.

The process of union of two gametes to form a zygote.

Haploid cell:
A cell containing only one set of chromosomes (n).


tetra- fourchiasm- marked crosswise
sporo-a seed

1 . A human cell containing 22 autosomes and a Y chromosome is

a) a somatic cell of a male.

b) a zygote.

c) a somatic cell of a female.

d) a sperm cell.

e) an ovum.

2 . Homologous chromosomes move toward opposite poles of a dividing cell during

a) mitosis.

b) meiosis I.

c) meiosis II.

d) fertilization.

e) binary fission.

3 . Meiosis II is similar to mitosis in that

a) homologous chromosomes synapse.

b) DNA replicates before the division.

c) the daughter cells are diploid.

d) sister chromatids separate during anaphase.

e) the chromosome number is reduced.

4. The immediate product of meiosis in a plant is a

a) spore.

b) gamete.

c) sporophyte.

d) gametophyte.

e) zygote.

5. Multicellular haploid organisms

a) are typically called sporophytes.

b) produce new cells for growth by meiosis.

c) produce gametes by mitosis.

d) are found only in aquatic environments.

e) are the direct result of fertilization.

6 . Crossing over usually contributes to genetic variation by exchanging chromosomal segments between

a) sister chromatids of a chromosome.

b) chromatids of nonhomologues.

c) nonsister chromatids of homologues.

d) nonhomologous loci of the genome.

e) autosomes and sex chromosomes.

Answers: 1. d, 2. b, 3. d, 4. a, 5. c, 6. c

Chapter 14

Norm of reaction:
The range of phenotypes produced by a single genotype, due to environmental influences.

The complete complement of an organism’s genes; an organism’s genetic material.

Law of Segregation:
Mendel’s first law, stating that each allele in a pair separates into a different gamete during gamete formation.

Polygenic inheritance:
An additive effect of two or more gene loci on a single phenotypic character.

An organism that is heterozygous with respect to two genes of interest. All the offspring from a cross between parents doubly homozygous for different alleles are dihybrids. For example, parents of genotypes AABB and aabb produce a dihybrid of genotype AaBb.

Recessive allele:
An allele whose phenotypic effect is not observed in a heterozygote.

Alternative versions of a gene that produce distinguishable phenotypic effects.

The physical and physiological traits of an organism, that are determined by its genetic makeup.

Quantitative characters:
A heritable feature that varies continuously over a range rather than in an either-or fashion.

Breeding of an organism of unknown genotype with a homozygous recessive individual to determine the unknown genotype. The ratio of phenotypes in the offspring determines the unknown genotype.

Dominant allele:
An allele that is fully expressed in the phenotype of a heterozygote.

An organism that is heterozygous with respect to a single gene of interest. All the offspring from a cross between parents homozygous for different alleles are monohybrids. For example, parents of genotypes AA and aa produce a monohybrid of genotype Aa.

The situation in which the phenotypes of both alleles are exhibited in the heterozygote.

The ability of a single gene to have multiple effects.

Incomplete dominance:
The situation in which the phenotype of heterozygotes is intermediate between the phenotypes of individuals homozygous for either allele.

Complete dominance:
The situation in which the phenotypes of the heterozygote and dominant homozygote are indistinguishable.

A type of gene interaction in which one gene alters the phenotypic effects of another gene that is independently inherited.

Referring to plants that produce offspring of the same variety when they self-pollinate.

In genetics, the mating, or crossing, of two true-breeding varieties.
Law of Independent Assortment:
Mendel’s second law, stating that each pair of alleles segregates independently during gamete formation; applies when genes for two characters are located on different pairs of homologous chromosomes.


-centesis- a puncture

epi- besides
geno- offspring

pedi- a child

1 . Which choice below is a basic difference between Mendel's particulate hypothesis and the blending hypothesis?

a) The blending hypothesis, but not the particulate hypothesis, maintained that mutation is the major source of new gene combinations.

b) The blending hypothesis, but not the particulate hypothesis, maintained that the two alleles at any given locus are always different.

c) The blending hypothesis, but not the particulate hypothesis, maintained that the traits governed by genes in the egg are different from the traits governed by genes in the sperm.

d) The blending hypothesis, but not the particulate hypothesis, maintained that after a mating, the genetic material provided by each of the two parents is mixed in the offspring, losing its individual identity.

e) All of the above.

2 . If a plant variety is true-breeding for a dominant trait, then _____.

a) if the plant were allowed to self-pollinate, the dominant and recessive traits would consistently appear in a 3:1 ratio among the progeny

b) the plant is heterozygous for the trait

c) if the plant were crossed with a heterozygote, one-half of the progeny would show the dominant trait, and one-half would show the recessive trait

d) if the plant were allowed to self-pollinate, all of the progeny would have the dominant trait

e) the variety is immune to mutation

3 . A = big apples; R = red apples; a = small apples; r = yellow apples. You have one tree that produces big yellow apples and another tree that produces small red apples. When the two are crossed, you find that half of the new trees produce big red apples and half produce big yellow apples. What are the genotypes of the parents?

a) AArr and aaRr

b) Aarr and aaRr

c) AARr and Aarr

d) AaRr and AaRr

e) AaRr and aarr

4 . Assume tall (T) is completely dominant to dwarf (t). If a homozygous dominant individual is crossed with a homozygous dwarf, the offspring will _____.

a) all be intermediate in height

b) all be tall

c) be 1/2 tall and 1/2 dwarf

d) be 3/4 tall and 1/4 dwarf

e) all be short

5 . The F1 generation differed from the F2 in Mendel's experiments in that _____.

a) all of the F1 showed the dominant phenotype, whereas only half of the F2 did

b) all of the F1 showed the dominant phenotype, but only three-fourths of the F2 did

c) all of the F1 showed the dominant phenotype, and all of the F2 showed the recessive phenotype

d) one-half of the F1 showed the dominant phenotype, and three-fourths of the F2 did

e) none of the F1 showed the dominant phenotype, but one-half of the F2 did

6 . In a certain plant, the alleles A, B, and C are completely dominant to the alleles a, b, and c. A plant with the genotype AABbcc will have the same phenotype as a plant with the genotype _____.

a) Aabbcc

b) aabbcc

c) AaBBcc


e) none of the above

Answers: 1. d, 2. d, 3. a, 4. b, 5. b, 6. c

Chapter 15

Genomic imprinting:
Phenomenon in which expression of an allele in offspring depends on whether the allele is inherited from the male or female parent.

(1) An aberration in chromosome structure resulting from attachment of a chromosomal fragment to a nonhomologous chromosome. (2) During protein synthesis, the third stage in the elongation cycle when the RNA carrying the growing polypeptide moves from the A site to the P site on the ribosome. (3) The transport of organic nutrients in the phloem of vascular plants.

A chromosomal aberration in which one or more chromosomes are present in extra copies or are deficient in number.

An offspring whose phenotype differs from that of the parents; also called recombinant type.

Map units:
A unit of measurement of the distance between genes. One map unit is equivalent to a 1% recombination frequency.

A chromosomal alteration in which the organism possesses more than two complete chromosome sets.

An aberration in chromosome structure resulting from reattachment in a reverse orientation of a chromosomal fragment to the chromosome from which the fragment originated.

An error in meiosis or mitosis, in which both members of a pair of homologous chromosomes or both sister chromatids fail to move apart properly.

Wild type:
An individual with the normal (most common) phenotype.

An aberration in chromosome structure due to fusion with a fragment from a homologous chromosome, such that a portion of a chromosome is duplicated.

(1) A deficiency in a chromosome resulting from the loss of a fragment through breakage. (2) A mutational loss of one or more nucleotide pairs from a gene.

Cytological maps:
Chart of a chromosome that locates genes with respect to chromosomal features.

Barr body:
A dense object lying along the inside of the nuclear envelope in female mammalian cells, representing an inactivated X chromosome.

Linkage map:
A genetic map based on the frequencies of recombination between markers during crossing over of homologous chromosomes.

Genetic map:
An ordered list of genetic loci (genes or other genetic markers) along a chromosome.

1. The chromosome theory of inheritance states that _____.

a) genes occupy specific positions on chromosomes

b) homologous chromosomes segregate from each other during meiosis

c) chromosomes assort independently during meiosis

d) The first and second answers are correct.

e) The first, second, and third answers are correct.

2 . Drosophila is a useful organism for genetic studies for all of the following reasons except _____.

a) They have a long generation time.

b) A single mating can produce many offspring.

c) They have a small number of chromosomes.

d) Drosophila chromosomes can be easily distinguishable under a light microscope.

e) All of the above.

3 . Wild type refers to _____.

a) the most common phenotype in the natural population

b) the most extreme mutant phenotype observed in an experiment

c) any mutant genotype

d) a kind of chromosomal deletion

e) extranuclear genes

4 . Which of the following statements about Thomas Hunt Morgan's experiments with white-eyed mutant flies is incorrect?

a) In the parental cross, a white-eyed male was crossed with a red-eyed female. The F1 progeny all had red eyes.

b) The F1 flies were crossed with each other, and the F2 progeny included red-eyed and white-eyed flies in a 3:1 ratio.

c) Among the F2 progeny, half of the males had white eyes.

d) Among the F2 progeny, half of the females had white eyes.

e) All of the above are incorrect.

5 . If two genes are linked, _____.

a) they are on different chromosomes

b) they assort independently

c) they code for the same protein

d) they are on the same chromosome

e) they are on sex chromosomes

6 . In a particular species of mammal, black hair (B) is dominant to green hair (b), and red eyes (R) are dominant to white eyes (r). When a BbRr individual is mated with a bbrr individual, offspring are produced in a ratio of 5 black hair and red eyes:5 green hair and white eyes:1 black hair and white eyes:1 green hair and red eyes. Which of these explanations accounts for this ratio?

a) Green-haired individuals have a higher prenatal mortality than black-haired individuals.

b) The genes for hair color and the genes for eye color are carried on different chromosomes.

c) The expected results did not take genetic recombination into account.

d) The genes for both of these traits are carried on the autosomes.

e) The genes for hair color and eye color are linked.

Answers: 1. e, 2. a, 3. a, 4. d, 5. d, 6. e


re- again
hemo- blood

aneu- without

Good luck everyone! Study hard and get lots of sleep!

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