BIO352 old exam questions

put the various stages in the cell cycle of a somatic cell in order

2, 3, 1, 5, 4

during which stage of meiosis do the non-sister chromatids begin to move towards the opposite poles of the spindle apparatus(assume no recombination/crossing over)

anaphase I

which of the following is true regarding interphase?

chromosomes are not visible but instead appear as chromatin, this phase consists of G1, S, G2

meiosis is described as a reduction division. when does the reduction in chromosome number occur?

anaphase I

a group of cells is assayed for immediately following mitosis and is found to have an average of X amount of DNA per nucleus. those cells would have _____ amount at the end of S phase and ____ amount at the end of G2.

2X and 2X

synapsis occurs during which of the following phases of meiosis:

zygonema

which of the following is false in comparing prophase I of meiosis and prophase of mitosis

tetrads form in both

what is the purpose of meiosis

to ensure the constancy of chromosome number from one generation to another and permit genetic variation

once telophase of mitosis is complete the cell has

half as much DNA as it did before anaphase

how many bivalents are formed in a cell with 10 chromosomes at the beginning of meiosis I

5

a tetrad is made up of

two homologous chromosomes, each consisting of two chromatids

which of the following is not true of sister chromatids

they segregated from each other during meiosis I

an organism has a haploid number of 20 chromosomes(1N=20). how many sister chromatids are observed in a diploid cell at mitotic metaphase

80

which of the following stages of meiosis increases genetic variability among gametes?

prophase I and anaphase I

an organism with a 1N number of 24 chromosomes would exhibit the following number of tetrads at metaphase of meiosis I:

24

which of the following characteristics does not apply to cells after meiotic telophase I

the daughter cells have the same number of chromosomes as the parent cell

in giant amazonian water lilies, red alleles(R) and white alleles(R) are incompletely dominant, which means that heterozygotes are pink. if a pink lily is pollinated by another pink lily, what percentage of the offspring will be pink?

50%

for an organism with 2n=16, how many tetrads are present at metaphase of the first meiotic division

8

a test cross is used to determine if the genotype of a plant with the dominant phenotype is homozygous or heterozygous. if the unknown is heterozygous, half of the offspring will have the _____ phenotype. if the unknown is homozygous, all of the offspring of the test cross have the ______ phenotype

recessive and dominant

in lima beans, seed color is either green or yellow. a cross between a pure breeding green bean and a pure breeding yellow bean yields 40 hybrid beans all of which were green. a cross between two of the plants that grew from these hybrid beans yielded 80F2 beans. how many of these F2 beans produces plants that had yellow seeds?

20

how many different gametes can be formed from the genotype AABbCcddeeFf?

8

if the shape, size, and color of gourds are traits determined by 3 independently assorting genes with dominant/recessive alleles, crossing two trihybrids heterozygotes will produce _____ different phenotypes

8

mendels laws and where each occurs in meiosis are as follows:

the principle of segregation states that two members of a gene pair segregate from each other in the formation of gametes(demonstrated in anaphase I). the principle of independent assortment states that the alleles for genes for different traits assort independently of each other(demonstrated in anaphase I)

a couple has four children whos blood types are A, A, B, and AB. which of the following parental genotypes are capable of producing the blood types of this couples children?

I^AI^O and I^BI^O

what phenotypic segregation ratios typically result from crosses dealing with a single genetic locus?

3:1, 1:1, and 1:2:1

the gametes of a plant of genotype SsYy should have the genotypes(assume independent assortment):

SY, Sy, Ys, and sy

in a tryhibrid cross, MmSsYy x MmSsYy, what fraction of the offspring will be homozygous dominant for all three trates

1/64

given incomplete dominance among the pairs of alleles at two of three loci and complete dominant/recessiveness among the pairs of alleles at the third locus, a cross between two thrihybrids will produce how many different phenotypes(assuming independent assortment) among the offspring?

18

the A and a alleles are codominant. at a separate, independently assorting gene, the B allele is completely dominant to the b allele. in the cross AaBb x AaBb how many different phenotypes are possible among the progeny?

6

assuming independent assortment, what proportion of the offspring of the cross AsBbCcDd x AabbCCdd will have the aabbccdd genotype?

0

in a F1 dyhybrid cross(WwGg x WwGg) where: W=round, w=wrinkled, G=yellow and g=green, what is the probability of obtaining an individual that is round, green and true breeding for both traits

1/16

in peas, a tall, yellow-seeded plant is crossed with a homozygous short, green-seeded plant and yields 203 tall, green-seeded plants, 199 short, green-seeded plants, 207 tall, yellow-seeded plants, and 192 short, yellow-seeded plants. the most likely genotype of the tall, yellow-seeded parent is:

TtYy

a linear chromosome with the centromere in the middle so that both arms are of equal length is called:

metacentric

one drosophila genotype PpMm is crossed with another genotype ppmm. if the P and M genes are absolutely linked in trans in the dihybrid parent:

none of the above(50%Pm and 50%mP)

consider a species with a haploid(1n) number of 10 chromosomes. how many chromosomes would be found in a tetrasomic body cell?

22

the number of Barr bodies in a human somatic cell is:

one less than the number of X chromosomes in that cell

with cytoplasmic inheritance:

the genes inherited in this manner can be found in the mitochondria, differences in cytoplasmic contributions from the mother(egg) and father(sperm) is important

how many chromosomes would be found in an allopolyploid(amphidiploid) plant if its original parent(progenitor species) had diploid numbers of 6 and 10 respectively?

haploid number of 8

two practical benefits of polyploidy that have been exploited by breeders are:

the associated bigger cell size and sterility

what is the easiest way to determine if a particular trait of an organism is inherited autosomally or is sex-linked

perform reciprocal crosses

assume that regarding a particular gene, one scored 40 second division ascospore arrangements(2:2:2:2 or 2:4:2) and 160 first division arrangements(4:4) in neurospora. what would be the map distance between the gene and the centromere

10

with the situation of complete interference, what would be the value for the coefficient of coincidence?

0.00

in humans, XYY individuals are males with Jacob’s syndrome. which of the following events could give rise to a Jacobs male?

nondisjunction at meiosis II in the father

which of the following individuals will have the MOST trouble in producing functional gametes during meiosis?

triploid with 30 total chromosomes

how is sex determined in drosophila

by the ratio of X chromosomes to the number of sets of autosomes

for a pseudoautosomal trait, if you cross a pure-breeding parent with the dominant trait with a pure-breeding parent with the recessive trait and compare the two F1 hybrid populations produced when performing reciprocal crosses, they will:

be phenotypically identical in terms of the trait controlled by the pseudoautosomal gene for both males and females

in chickens, it is the females that have two different sex chromosomes(Z and W) while the males have two Z chromosomes. A Z-linked gene controls the pattern of the feathers with the dominant B allele causing the barred pattern and the b allele causing non-barred feathers. you cross a non-barred female with a heterozygous barred male. what do you expect for the phenotype of the progeny?

daughters and sons of both types

you cross a gray cat with a brown cat. The offspring are all black. you cross two of the offspring, and get 9/16 black, 4/16 grey, and 3/16 brown. from the following choices given, which is most likely to represent the genotype of a gray cat from the F2 offspring?

aaBB

which of the following modes of inheritance best explains this pedigree?

X-linked dominant

which of the following modes of inheritance best explains this pedigree?

autosomal recessive

in the WZ/ZZ system, females are the heterogametic sex

true

which of the following statements correctly describes telomerase?

telomerase extends the 3’ ends of the lagging strand template of linear chromosomes

what is the function of the dnaA helicase?

it allows for initiation of a DNA replication event at the Ori C region

which DNA will have the lowest density given the following G+C/A+T ratios?

1/5

if an individual is heterozygous for a reciprocal translocation, we would expect about a:

50% reduction in fertility

in an analysis of the nucleotide composition of double-stranded DNA to see which bases are equivalent in concentration, which of the following would be true?

A+C=G+T

RNA is transcribed in a:

5’ to 3’ direction from the non-coding DNA strand, with the transcription bubble moving along the non-coding strand in a 3’ to 5’ direction

in prokaryotic transcription, the role of the sigma factor is:

to recognize consensus sequences in the promotor region of a gene to initiate transcription

the following diagram shows a fragment of a transcribed gene sequence(the upper strand is the coding strand), the transcribed RNA is:

5’ATTGCC3’

3’TAACGG3’

5’AUUGCC3’

because of a reciprocal translocation involving non-homologous chromosomes, a growth gene suddenly finds itself expressed at a much higher rate and the cell becomes cancerous. This activation of the growth gene is because of:

position effects

the picture below depicts possible DNA banding pattern results of the Meselson and Stahl experiment. what conclusion do these results support?

these results support BOTH the dispersive and semi-conservative models of replication

in a reciprocal translation heterozygote, what is the pattern of homologous chromosome association during synapsis?

a cross shaped configuration of four chromosomes is formed

DNA replication is carried out in prokaryotes by DNA polymerase III. Which of the following statements correctly summarizes the properties of the enzyme?

it requires a preexisting nucleic acid chain with a free 3’ -OH to add on to

a fundamental difference between DNA polymerase I(kornberg enzyme) and DNA polymerase III of E. coli is:

I has 5’ to 3’ exonuclease activity and III does not

what function does 3’ to 5’ exonuclease activity allow a DNA polymerase to perform?

proofreading or error correction

the function of the rho protein is:

to help terminate transcription

DNA exhibits maximum absorption of which wavelength of light?

260nm

DNA polymerase III requires a/an ______ for synthesis for DNA to occur

availability of all 4 dNTP’s, RNA primer, DNA template

in RNA, which of the following is true:

none of the above

which enzyme removes the RNA primer during replication in E. coli

DNA polymerase I

which of the following statements is true:

okasaki fragments are different in size in prokaryotes and eukaryotes because fundamental aspects of the mechanism for replication in the two systems are different