Bio: exam 3 review launchpad questions

B

A eukaryotic chromosome has _____ origin(s) of replication, and a bacterial chromosome has _____ origin(s) of replication. A. one; one B. many; one C. one; many D. many; two E. many; three

A

A new nucleotide can only be added to the _____ end of a growing DNA strand. DNA therefore always grows in the _____ direction. A. 3'; 5' to 3' B. 5'; 5' to 3' C. 3'; 3' to 5' D. 5'; 3' to 5'

B

A skin cell in G2 of interphase has _____ as much DNA as it had in G1. A. half B. twice C. exactly D. one-fourth E. four times

A

Imagine that you are examining a mouse that does not produce basal lamina in the skin. How will this mouse be different from a normal, wild-type mouse? A. The epidermis will not be connected to the dermis. B. The epidermis and dermis will be strongly connected. C. The dermis will be disorganized and will lack blood vessels. D. Cellular junctions will fail to form between the cells of the epidermis. E. All of these choices are correct.

A

If a mutation occurred in the cadherin gene so that the cytoplasmic domain no longer attached to the cytoskeleton, which of the following would occur? A. Cadherins in desmosomes would no longer be anchored to intermediate filaments B. Cadherins in adherens junctions would no longer be anchored to microtubules C. Cadherins in hemidesmosomes would no longer be anchored to intermediate filaments D. Cadherins in desmosomes would no longer be anchored to microfilaments

D

In observing DNA replication in the lab, you notice that in some cells, a defect occurs where DNA replication proceeds, but the RNA primers are not removed and replaced with DNA. Which enzyme is MOST likely to be defective in this system? A. RNA primase B. helicase C. single-strand binding protein D. DNA polymerase E. DNA ligase

C

During meiosis II: A. bivalents are formed during prophase II and are taken apart during anaphase II. B. chromosomes undergo reductional division. C. sister chromatids are separated. D. non-sister chromatids exchange maternal and paternal DNA. E. All of these choices are correct.

C

Dynein is a motor protein found attached to: A. lamin B. microfilaments C. microtubules D. intermediate filaments

D

How does an adherens junction differ from a desmosome? A. An adherens junction connects a cell to neighboring cells, and a desmosome connects a cell to the extracellular matrix. B. An adherens junction connects cells using adherin proteins, and a desmosome connects cells using cadherin proteins. C. Whereas both adherens junctions and desmosomes connect cells by using cadherin proteins, only an adherens junction connects to the cytoskeleton. D. Whereas both adherens junctions and desmosomes connect cells by using cadherin proteins, adherens junctions connect to microfilaments in the cytoplasm and desmosomes connect to intermediate filaments. E. These two types of junctions only differ in their bandlike versus button-like architecture in the plasma membrane.

A

How many copies of each gene are present in human skin cells at G1 of interphase? A. 2 B. 4 C. 6 D. 8

D

How would the loss of p53 activity affect a cell? A. The G1/S checkpoint would not be functional. B. DNA damage could accumulate. C. CDK activity would not be appropriately regulated. D. All of these choices are correct.

E

Intermediate filaments: A. have a diameter that is larger than a microfilament, but smaller than a microtubule. B. play an important role in maintaining cell shape. C. play an important role in preventing skin from tearing by shear stress. D. undergo little change in length in comparison to microtubules and microfilaments. E. All of these choices are correct.

A

Kinesin motor proteins use ATP to: A. carry vesicles along a microtubule within a cell in a minus-to-plus direction. B. carry vesicles along a microfilament within a cell in a minus-to-plus direction. C. carry vesicles along a microtubule within a cell in a plus-to-minus direction. D. carry vesicles along a microfilament within a cell in a plus-to-minus direction. E. slide along microfilaments to contract muscle cells.

A

Microfilaments increase in length: A. more quickly at one end than the other. B. by assembling outward from the centrosome. C. in cycles, following rapid depolymerization. D. if free tubulin dimers are available. E. All of these choices are correct.

B

Muscle cells in the mammalian heart are multinucleate, meaning that multiple nuclei are present in the cytoplasm of a large cell. Predict what is different about the cell cycle in a muscle cell. A. The G1 and G2 phases are extended. B. Cytokinesis does not occur. C. S phase happens twice. D. M phase is inhibited.

B

Myosin motor proteins use ATP to: A. carry vesicles along a microtubule within a cell in a minus-to-plus direction. B. carry vesicles along a microfilament within a cell in a minus-to-plus direction. C. carry vesicles along a microtubule within a cell in a plus-to-minus direction. D. carry vesicles along a microfilament within a cell in a plus-to-minus direction. E. slide along intermediate filaments to contract muscle cells.

C

Paired chromosomes in a cell that share the same set of genes are called: A. sister chromatids B. bivalent chromosomes C. homologous chromosomes D. non-sister chromatids

D

Replication of DNA in a eukaryote occurs during which phase of the cell cycle? A. M phase B. G1 phase C. G2 phase D. S phase

E

Sister chromatids are BEST described as two DNA molecules that have: A. the same genes in the same order but having different alleles B. the same alleles of the same genes in a different order C. different genes in the same order and possibly having different alleles of some genes D. different alleles of the same genes arranged in a different order E. virtually identical sequences of nucleotides

C

Sister chromatids are separated during: A. mitosis. B.meiosis I and mitosis. C. meiosis II and mitosis D. meiosis I. E. meiosis II.

E

Some cytoskeletal elements are more permanent than others. Which components of the cytoskeleton are dynamic structures? A. microtubules B. microfilaments C. intermediate filaments D. both microtubules and intermediate filaments E. both microtubules and microfilaments

C

Suppose you add fluorescent ribonucleotides to a cell undergoing DNA replication so that the RNA primers used in DNA synthesis glow when viewed with a fluorescent microscope. You notice that, near each replication fork, one strand glows more than the other. Which strand is it that glows more, and why? A. The leading strand glows more because it is elongated nearest the replication fork. B. The leading strand glows more because it forms the "trombone loop." C. The lagging strand glows more because its RNA primer is nearer the replication fork. D. The lagging strand glows more because it forms the "trombone loop."

B

The leading strand is the daughter strand that has its ___ end pointed toward the replication fork and is therefore synthesized ____. A. 3'; in a series of segments B. 3'; continuously C. 5'; in a series of segments D. 5'; continuously E. None of the other answer options is correct

False

The semiconservative model of DNA replication means that each DNA strand consists of some newly synthesized DNA and some parental DNA. True False

D

What feature of double-stranded DNA makes it necessary to have a leading strand and a lagging strand during replication? A. the hydrogen bonding between bases B. the base stacking of the bases C. the negative charge on the sugar-phosphate backbone D. the antiparallel orientation of the strands

D

What would happen if a chromosome only connected to the mitotic spindle at one of its kinetochores? A. One of the daughter cells would have an extra copy of that chromosome. B. The sister chromatids would not separate. C. The chromosome would not line up properly at metaphase. D. All of these choices are correct.

D

Which of the following enable(s) the movement of cells? A. microtubules B. microfilaments C. intermediate filaments D. microtubules and microfilaments E. microfilaments and intermediate filaments

D

Which of the following enzymes is responsible for unwinding the double helix at the replication fork? A. ligase B. DNA polymerase C. primase D. helicase E. topoisomerase

D

Which of the following is NOT true about cadherins? A. Cadherins are cell adhesion molecules found in cell junctions. B. Cadherins are proteins involved in attachment of cells to neighboring cells. C. Cadherins are proteins involved in attachment of cells to the extracellular matrix. D. Cadherins are proteins that provide a pathway for molecules to move between cells.

C

Which of the following is a FALSE statement about the motor proteins myosin and kinesin? A. They both use ATP. B. They both move cargo to the plus end of a cytoskeletal filament. C. They both move along microtubules. D. None of these statements about myosin and kinesin is false.

A

Which of the following statements about the skin is TRUE? A. The epidermis is made up of epithelial tissue whereas the dermis is made up primarily of connective tissue. B. The epidermis is made up of connective tissue whereas the dermis is made up primarily of epithelial tissue. C. The epidermis and the dermis are made of the same tissue, called epithelial tissue. D. The epidermis and the dermis are made of the same tissue, called connective tissue.

A

Which of the following statements is TRUE if a cell has a mutation in the p53 gene such that the p53 protein is no longer able to be phosphorylated? A. The cell would proceed through the cell cycle even in the presence of DNA damage. B. The cell would arrest, giving time for the DNA damage to be repaired. C. The amount of cytoplasmic p53 protein would increase in response to DNA damage. D. The kinase activity in the nucleus would decrease in response to DNA damage.

D

Which one of the following is a characteristic shared by integrins and cadherins? A. Both are peripheral membrane proteins. B. Both facilitate the adhesion of cells to extracellular matrix proteins. C. Both are present in adherens junctions, desmosomes, and hemidesmosomes. D. The cytoplasmic domains of both proteins are connected to the cytoskeleton.

A

Which type of cell junction prevents the movement of substances through the space between cells? A. tight junctions B. adherens junctions C. desmosomes D. hemidesmosomes E. gap junctions

A and C

Why is DNA ligase important for a cell? (Select all that apply.) A. It joins Okazaki fragments. B. It relieves the stress of DNA unwinding. C. It joins DNA together from different origins of replication. D. It unwinds DNA.

C

p53 is an example of a(n): A. oncogene B. proto-oncogene C. tumor suppressor D. cyclin-dependent kinase