bsc114 final exam - daryl lam

genetics

study of heredity and inherited variation

heredity

transmission of traits from one generation to the next

inherited variation

inherited similarity in a trait

genes

hereditary units made up on DNA

what produces copies of the genes that can be passed from parents to offspring?

replication

locus

a gene's specific location on a chromosome

what does asexual reproduction produce?

offspring that are genetically identical to the parent

in asexual reproduction, a single individual is the sole parent and passes on all of its genes...

directly to its offspring

example of a multi-cellular organism that can reproduce asexually

hydra

what does sexual reproduction involve?

the uniting of genes from 2 parents

what results from sexual reproduction in comparison to asexual reproduction?

much greater genetic variation

gametes

reproductive cells in plants and animals that pass genes from one generation to the next

diploid cells

have two copies of each chromosome

homologous chromosomes

pairs of chromosomes

haploid cells

one of each homologous chromosomes

meiosis chromosomes

diploid to haploid

fertilization chromosomes

haploid to diploid

human haploid chromosome number

23

somatic cells are...

diploid

1 multiple choice option

gametes are...

haploid

1 multiple choice option

sex chromosomes

chromosomes that determine genetic sex

autosomes

all chromosomes except sex chromosomes

females

two X chromosomes

males

one X chromosome, one Y chromosome

males are __________ for 22 autosomes, but __________ for the 2 sex chromosomes

diploid; haploid

1 multiple choice option

meiosis (from a chromosome perspective)

process that halves the diploid set to a single haploid set of chromosomes, resulting in the haploid germ cells

fertilization (from a chromosome perspective)

restores the diploid set of chromosomes

eggs have...

one X chromosome

sperm provides:

either an X or Y chromosome

which gamete determines the genotypic sex of the offspring?

sperm

1 multiple choice option

meiosis reduces the chromosome number during...

gametogenesis

fertilization

fusion of gametes (egg and sperm) to produce a zygote

each gamete contributes how much of its genetic material to offspring?

half

1 multiple choice option

mitosis

each daughter cell contains exactly the same genetic info as the mother cell

meiosis

each daughter cell is unique, and contains only half of the genetic information of the "mother" cell

how many divisions occur in meiosis?

2

how many cells does meiosis produce?

4 haploid cells

in meiosis, homologous chromosomes move to opposite sides of the cell in:

anaphase I

3 multiple choice options

in meiosis, homologous chromosomes:

align on the metaphase plate in meiosis I

3 multiple choice options

in peas, purple flowers are dominant over white flowers. If two heterozygotes are crossed, what fraction of the population will have white flowers?

1 out of 4 (25%)

3 multiple choice options

if a somatic cell has 10 chromosomes, then each gamete would have how many chromosomes?

5

3 multiple choice options

a 9:3:3:1 phenotypic ratio is characteristic of which of the following?

a dihybrid cross

3 multiple choice options

in its most basic form, evolution is defined as change in _________ in a population over time.

allele frequency

3 multiple choice options

viral disease are difficult to treat because viruses:

do not have their own metabolism

3 multiple choice options

prophase of meiosis I has some important differences from prophase of mitosis. in meiosis, homologous chromosomes ____________________, and ____________________ occurs

form pairs; crossing over

3 multiple choice options

during meiosis, crossing over takes place between:

non-sister chromatids

3 multiple choice options

how many complete daughter cells are produced by the process of meiosis?

4

3 multiple choice options

at the start of meiosis I, the parent cell is ______________; at the end of meiosis II, the daughter cells are _______________.

diploid; haploid

3 multiple choice options

mitosis has _____ division(s), while meiosis has _____ division(s)

1; 2

3 multiple choice options

which is true?

errors in chromosome segregation can occur in either the first or second meiotic division

2 multiple choice options

in normal meiosis, when do homologous chromosomes separate from each other?

in the first meiotic division

2 multiple choice options

what is nondisjunction?

failure of chromosomal separation

3 multiple choice options

if nondisjunction occurs in the first meiotic division, how many of the four possible gametes produced from meiosis will have a different number of chromosomes than expected?

four

3 multiple choice options

in which type of nondisjunction could the two copies of a chromosome in a gamete be heterozygous?

nondisjunction in the second meiotic division

2 multiple choice options

it is estimated that a human cell in G1 phase of the cell cycle contains 6 picograms of DNA in its nucleus. if you measure the DNA content at various stages of meiosis, what quantities of DNA can be expected in each nuclei at the following stages?

prophase I: __________; prophase II (per cell): __________; cytokinesis II ___________________. (all amounts are in picograms (10^-12g))

12; 6; 3

3 multiple choice options

synapsis is best described as:

the pairing of homologous chromosomes in prophase I

3 multiple choice options

sexual reproduction results in an increase in genetic diversity because:

all of these choices are correct

3 multiple choice options

sexual reproduction results:

* from combining genetic material from two gametes

* in offspring that are not genetically identical

* in a new generation with the same number of chromosomes as each parent

* in a new generation that is not genetically identical to its parents

all of these choices are correct

3 multiple choice options

how does meiosis generate genetic diversity?

both crossing over at prophase I and random alignment of homologs at metaphase I

3 multiple choice options

would genetic recombination result if crossing over occurred between sister chromatids?

no, because sister chromatids are genetically identical

3 multiple choice options

mammals are ____________ and produce ____________ gametes

diploid; haploid

3 multiple choice options

which choices accurately match each of the cellular processes to the stage of meiosis in which it occurs?

i. sister chromatids move toward opposite poles of the cell in anaphase II

ii. homologous chromosomes undergo synapsis in prophase II

iii. both chromatids of homologous chromosomes migrate to the same pole in anaphase I

iv. crossing over occurs between homologous chromosomes in prophase II

i and iii

3 multiple choice options

which of the options correctly match the type of cell division with the cellular events or results characteristic of that type of cell division? select all that apply

i. mitosis produces genetically identical daughter cells

ii. mitosis produces 4 daughter cells

iii. meiosis produces genetically unique daughter cells

iv. in mitosis, homologous chromosomes undergo synapsis

v. in meiosis, the original cell undergoes two rounds of cell division

i, iii, and v

3 multiple choice options

the ___________ of an individual describes the combination of ___________ present, and the ___________ constitutes the expression of the ___________

genotype; alleles; phenotype; trait

3 multiple choice options

consider a situation in which a ranch has a herd of cattle with brown hides and short horns. all of their cattle are also relatively short in stature. if all of these were true-breeding traits, what could you say about the progeny of these cattle?

the progeny of these cattle will be short in stature and have brown hides and short horns

3 multiple choice options

what is an allele?

one of several different forms of a gene

3 multiple choice options

a true-breeding black rabbit is crossed with a true-breeding white rabbit to produce an F1 generation of 16 individuals. if the black color trait is dominant, which answer option represents the expected phenotype of the F1 generation?

16 black rabbits; 0 white rabbits; 0 gray rabbits

3 multiple choice options

a woman has her personal genome analyzed for the BRCA1 mutation after learning that her father is heterozygous and carries one mutant allele. what is her chance of inheriting the mutant allele from her father?

50%

3 multiple choice options

according to the principle of segregation, a heterozygous plant with alleles Aa will produce:

gametes in the ratio of 1 A allele : 1 a allele

3 multiple choice options

which answer option represents the expected genotypes of an F2 generation consisting of eight individuals from an initial cross of a true-breeding black (BB) rabbit and a true-breeding white (bb) rabbit?

8 progeny: 2 BB, 2 bb, 4 Bb

3 multiple choice options

suppose you have a plant whose flowers have the dominant color phenotype, but you would like to know if the plant is homozygous or heterozygous. what cross, and with what predicted results, could you perform that would determine that this plant has a heterozygous genotype?

testcross; 1/2 dominant phenotype : 1/2 recessive phenotype

3 multiple choice options

if you crossed a true-breeding yellow-seed plant (AA) with a heterozygous yellow-seed plant (Aa), offspring:

genotypes would be 1 AA : 1 Aa

3 multiple choice options

which of these statements is not true of a punnett square?

the ordering of the letters on the axes matters

3 multiple choice options

in his cross, what did mendel do?

he studied traits controlled by a single gene

2 multiple choice options

in mendel's crosses:

the plants he started with had two alleles of each gene

2 multiple choice options

how did mendel make crosses with his plants?

he grew plants from seeds and fertilized the ovules of one plant with the pollen from another

3 multiple choice options

when mendel crossed yellow peas with green peas, the next generation was all yellow. how is this explained?

the parental plants pass one of their two alleles on to the offspring which is heterozygous, and the A allele is dominant to the a allele

2 multiple choice options

mendel's principle of segregation corresponds to what part of meiosis?

separation of homologs in anaphase I

3 multiple choice options

if you crossed two heterozygous yellow-seed pea plants (genotypes Aa), the relative frequency of:

a. green-seed plants (genotype aa) would be 1/4

b. homozygous yellow-seed plants (genotype AA) would be 1/4

c. the a allele in each parent's gametes would be 1/2

d. the A allele in each parent's gametes would be 1/2

all of these choices are correct

3 multiple choice options

when the terms heterozygous and homozygous are used, what is being referred to?

a genotype of a trait

3 multiple choice options

a true-breeding black rabbit is crossed with a true-breeding white rabbit. if the black color trait is dominant, which answer option represents the expected phenotype of an F2 generation consisting of eight individuals?

6 black rabbits, 2 white rabbits, 0 gray rabbits

3 multiple choice options

suppose that in humans the ability to roll the tongue (R) is dominant to being unable to roll it (r), and having freckles (F) is dominant to having no freckles (f). a man heterozygous for both traits marries a woman heterozygous for both traits. what is the probability that they will have a child with freckles?

3/4

3 multiple choice options

genes that modify the phenotypic expression of other genes show:

epistasis

3 multiple choice options

genes can have up to two different alleles.

true

1 multiple choice option

mendel's principle of independent assortment corresponds to which part of meiosis?

random alignment of homologs on the metaphase plate during metaphase I

3 multiple choice options

in pea plants, flowers are either white or purple; the purple color is produced by pigments called anthocyanins. the production of anthocyanins is a two-step process: the first step is controlled by the C gene and the second by the P gene. both genes must produce functional proteins for anthocyanin to be expressed. for each gene, the dominant (C and P) alleles produce functional proteins. you cross two pea plants, each with the genotype CcPp. what proportion of their offspring will have white flowers (no anthocyanin produced)?

7/16

3 multiple choice options

you are given two true-breeding groups of rabbits. the first group has floppy ears and white fur. the second group has straight ears and black fur. when you perform a cross of these two groups to obtain an F1 generation you see that all of your rabbits have floppy ears and gray fur. which possibility appears to be supported by what you see in the F1 generation?

floppy ears are dominant over straight ears; fur color is determined by incomplete dominance

3 multiple choice options

suppose that in humans, the ability to roll the tongue (R) is dominant to being unable to roll it (r). having freckles (F) is dominant to having no freckles (f). say an individual has the genotype, Rrff. what are the potential gametes it could form?

* rf

* Rf

the concept of reverse transcription was at first very controversial because it:

contradicted the "central dogma" that the direction of expression of genetic information is always from DNA to RNA to protein

3 multiple choice options

a virus achieves host specificity through __________ on the surface of the capsid or envelope, which bind to specific receptor molecules on the surface of the host cell.

proteins

3 multiple choice options

which of the following present challenges that prevent the development of a flu vaccine that could last a lifetime and not require annual vaccination with new vaccines? select all that apply.

i. a high rate of infection by two or more flu strains at the same time

ii. a high mutation rate of the viral genome

iii. a low rate of mutation in the viral genome

iv. the development of a vaccine that includes highly conserved regions of the hemagglutinin gene

i and ii

3 multiple choice options

which of the examples are cellular life forms: virus, yeast, bacteria, plant, animal?

all are cellular except viruses

3 multiple choice options

which one of the statements about viruses is correct?

a. viruses use the cellular machinery of other organisms to replicate the virus's genetic material

b. some types of viruses integrate their own genomes into the genome of the host organism

c. the genomes of viruses are enclosed in a protein coat and occasionally a lipid bilayer envelope

d. viruses are valuable tools in biological research

all of these choices are correct

3 multiple choice options

which characteristic(s) is/are true of all viruses?

i. they contain a double-stranded RNA genome

ii. they contain a DNA genome

iii. they have a protein coat called a capsid

iv. they are surrounded by a lipid envelope

v. they must infect a host cell to reproduce

iii and v

3 multiple choice options

which of the choices would allow the flu vaccine to be effective for many years and not have to be changed with each year's flu season?

all of these choices are correct

3 multiple choice options

the enzyme reverse transcriptase synthesizes:

DNA from RNA

3 multiple choice options

a virus achieves host specificity through ___________ on the surface of the capsid or envelope, which bind to receptor molecules on the surface of the host cell.

proteins

3 multiple choice options

a cell in which viral reproduction occurs is called a:

host cell

3 multiple choice options

the ebola virus is highly virulent and pathogenic, causing severe disease that kills up to 70% of infected individuals. given this very high virulence and pathogenicity, what must be true about the transmission rate of the ebola virus given its persistence in populations?

the ebola transmission rate must be very high

2 multiple choice options

viruses with a DNA genome require a virus-encoded DNA polymerase.

false

1 multiple choice option