Final Exam Bio 111 Part 4

In pea plants, the tall phenotype is dominant to the dwarf phenotype. If a heterozygous pea plant is crossed with a homozygous tall pea plant, what is the probability that the offspring will be dwarf in size?

0

Black fur in mice (B) is dominant to brown fur (b). Short tails (T) are dominant to long tails (t). What fraction of the progeny of crosses BbTt × BBtt will be expected to have black fur and long tails

1/2

Albinism is a recessive trait. A man and woman both show normal pigmentation, but both have one parent who has albinism (without melanin pigmentation). What is the probability that their first child will have albinism?

1/4

If a cell at metaphase of mitosis contains 20 sister chromatids, how many chromosomes will be present in a G1 cell?

10

When Mendel crossed yellow-seeded and green-seeded pea plants, all the offspring were yellow-seeded. When he took these F1 yellow-seeded plants and crossed them to green-seeded plants, what genotypic ratio was expected?

1:1

If there are 40 centromeres in a cell at anaphase of mitosis, how many chromosomes will be found in each daughter cell following cytokinesis?

20

Starting with a fertilized egg (zygote), a series of six cell divisions would produce an early embryo with how many cells?

64

How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCCDdEE?

8

Gene S controls the sharpness of spines in a type of cactus. Cacti with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cacti have dull spines. At the same time, a second gene, N, determines whether or not cacti have spines. Homozygous recessive nn cacti have no spines at all. If cacti heterozygous for both traits, SsNn, were allowed to self-pollinate, the offspring would segregate into which of the following phenotype ratios?

9 sharp-spined:3 dull-spined:4 spineless

Which of the following properties is associated with a cyclin-dependent kinase (Cdk)

A Cdk is an enzyme that attaches phosphate groups to other proteins.

Albinism is a recessive trait. A man and woman who both have normal pigmentation have one child out of three who has albinism (without melanin pigmentation). What are the genotypes of this child's parents?

Both parents must be heterozygous.

Which of the following calculations require the use of the addition rule of probability?

Calculate the probability of a child having either sickle-cell anemia or cystic fibrosis if parents are each heterozygous for both

Suppose you are provided with an actively dividing culture of E. coli bacteria to which radioactive thymine has been added. What would happen if a cell replicates once in the presence of this radioactive base?

DNA in both daughter cells would be radioactive.

In E. coli, which enzyme catalyzes the elongation of a new DNA strand in the 5' → 3' direction?

DNA polymerase III

Why does a new DNA strand elongate only in the 5' to 3' direction during DNA replication?

DNA polymerase can add nucleotides only to the free 3' end.

A gene for the MN blood group has codominant alleles M and N. If both children in a family are of blood type M, which of the following situations is possible?

Each parent is either M or MN.

The beginning of anaphase is indicated by which of the following processes?

Enzymatic cleavage of cohesin

Gray seed color in peas is dominant to white. Assume that Mendel conducted a series of experiments where plants with gray seeds were crossed among themselves, and the following progeny were produced: 302 gray and 98 white. What is the most probable genotype of each parent?

Gg × Gg

Which of the following scenarios describes an example of epistasis

In rabbits and many other mammals, one genotype (ee) prevents any fur color from developing.

If a cell has completed meiosis I and the first cytokinesis, and is just beginning meiosis II, which of the following is an appropriate description of its genetic contents?

It has half the amount of DNA as the cell that began meiosis.

What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?

It joins Okazaki fragments together.

In E. coli, there is a mutation in a gene called dnaB that alters the helicase that normally acts at the origin of replication. Which of the following events would you expect to occur as a result of this mutation?

No replication fork will be formed.

How do cells at the completion of meiosis compare with cells that are in prophase of meiosis I?

The cells have half the number of chromosomes and one-fourth the amount of DNA.

Mendel crossed yellow-seeded and green-seeded pea plants and then allowed the offspring to self-pollinate to produce an F2 generation. The results were as follows: 6,022 yellow and 2,001 green (8,023 total). Which of the following statements correctly describes the relationship of the allele for green seeds to the allele for yellow seeds?

The green allele is recessive to the yellow allele.

Which of the following statements correctly describes the difference between the leading and the lagging strands of DNA during DNA replication?

The leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction.

What role do phosphatases play in signal transduction pathways?

They inactivate protein kinases to turn off signal transduction.

A cleavage furrow is ________.

a groove in the plasma membrane between daughter nuclei

Mendel's law of independent assortment has its basis in which of the following events of meiosis I?

alignment of pairs of homologous chromosomes along the middle of the cell

Gene S controls the sharpness of spines in a type of cactus. Cacti with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cacti have dull spines. At the same time, a second gene, N, determines whether or not cactuses have spines. Homozygous recessive nn cactuses have no spines at all. A cross between a true-breeding sharp-spined cactus and a spineless cactus would produce

all sharp-spined progeny

In the cells of many eukaryotic species, the nuclear envelope has to disappear to permit which of the following events in the cell cycle?

attachment of microtubules to kinetochores

Many organisms spend most of their life cycle in the diploid state. If meiosis produces haploid cells, how is the diploid number restored for these types of organisms?

by fertilization

Consider this pathway: epinephrine → G protein-coupled receptor → G protein → adenylyl cyclase → cAMP The second messenger in this pathway is ________.

cAMP

During which of the following processes do sister chromatids separate from each other?

during both mitosis and meiosis II

Hydrangea plants of the same genotype are planted in a large flower garden. Some of the plants produce blue flowers and others pink flowers. This can be best explained by which of the following?

environmental factors such as soil pH affect the phenotype

Asexual reproduction occurs during which of the following processes?

mitosis

G1 is associated with which of the following cellular events

normal growth and cell function

In E. coli, to repair a thymine dimer by nucleotide excision repair, in which order do the necessary enzymes act?

nuclease, DNA polymerase, DNA ligase

Semiconservative replication involves a template. What is the template?

one strand of the DNA molecule

An inhibitor of which of the following enzymes could be used to block the release of calcium from the endoplasmic reticulum?

phospholipase C

Which of the following inheritance patterns describes the ability of a single allele to have multiple phenotypic effects?

pleiotropy

At which phase of the cell cycle do centrioles begin to move apart in animal cells?

prophase

Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The part of the radish we eat may be oval or long, with long being the dominant trait. If true-breeding red long radishes are crossed with true-breeding white oval radishes, the F1 will be expected to exhibit which of the following phenotypes?

purple and long

Which of the following events occurs during interphase of the cell cycle?

replication of the DNA

In cattle, roan coat color (mixed red and white hairs) occurs in the heterozygous (CRCW) offspring of red (CRCR) and white (CWCW) homozygotes. Which of the following crosses would produce offspring in the ratio of 1 red:2 roan:1 white?

roan × roan

Movement of the chromosomes during anaphase would be most affected by a drug that prevents which of the following events in mitosis and cell division?

shortening of microtubules

Which of the following phenotypes is an example of polygenic inheritance?

skin pigmentation in humans

Which of the following processes occurs in meiosis but not in mitosis?

synapsis of chromosomes

FtsZ is a bacterial cytoskeletal protein that forms a contractile ring involved in binary fission. Its function is analogous to ________.

the cleavage furrow of eukaryotic animal cells