Exam 3 Homework Questions

Match the terms to the correct description

Mitosis: Division of the nucleus

Interphase: G1, S, G2 phases

Prophase: Chromosomes start to condense

Cytokinesis: Division of the cytoplasm

Metaphase: Chromosomes align on the plate

Prometaphase: Condensation of chromosomes is completed

Telophase: 2 daughter nuclei form in the cell and the chromosomes uncoil

Anaphase: sister chromatids separate

The unlettered circle at the top of the accompanying figure shows a diploid nucleus with four unduplicated chromosomes. The circles labeled 1 (I) to 5 (V) show various combinations of these chromosomes.

Which chromosomal configuration would be observed in one daughter cell after telophase of mitosis? V

Which chromosomal configuration would be observed at prometaphase of mitosis? II

How many chromosomes are present in cell V? 4

How many sister chromatids are present in cell IV? 4

Using the following description to match the question to its answer.

A Chinese hamster has a diploid number of 44 (2n=44)

A hamster cell has 22 duplicated chromosomes migrating to one cell pole and 22 duplicated chromosomes migrating to another cell pole. What is the cell stage of this cell? Anaphase 1

A hamster cell has 22 chromatids migrating to one cell pole and 22 chromatids migrating to another cell pole. What is the cell stage of this cell? Anaphase 2

Match the events of meiosis with the stages listed

Homologous chromosomes are aligned at the metaphase plate. Metaphase 1

Sister chromatids separate. Anaphase 2

Four haploid cells form containing joined sister chromatids. Telophase 2

Separation of the homologous chromosomes. Anaphase 1

Two daughter cells form containing a complete haploid set of duplicated chromosomes. Telophase 1

Alignment of chromosomes to the metaphase plate. Metaphase 2

Exchange of genetic material between non-sister chromatids of homologous chromosomes. Prophase 1

Students in a biology lab isolated cells in various phases of the cell cycle. A population of cells that have 1 1/2 times (1.5x) the DNA of G1 phase cells was most likely isolated from which of the following parts of the cell cycle?

between the G1 and S phases

in the G2 phase

in the M phase

in the S phase

In the S phase

Pigs have 38 chromosomes in each somatic cell (2n=38). One pig somatic cell undergoes mitosis. How many daughter cells are formed, and what is the chromosome number in each daughter cell?

Four cells with 38 chromosomes in each cell

Two cells with 19 chromosomes in each cell

Two cells with 38 chromosomes in each cell

Four cells with 19 chromosomes in each cell

2 cells with 38 chromosomes in each cell

Which of the following events would be most likely to produce cells with several nuclei?

repeated cytokinesis without mitosis

repeated mitosis with simultaneous cytokinesis

repeated mitosis without cytokinesis

multiple S phases without mitosis

repeated mitosis without cytokinesis

If there are 24 centromeres in a cell at anaphase of mitosis, how many chromosomes will be found in each daughter cell following cytokinesis?

6

12

24

48

12

Movement of the chromosomes during anaphase would be most directly affected by a drug that prevents which of the following events?

nuclear envelope breakdown

elongation of microtubules

shortening of microtubules

formation of a cleavage furrow

Shortening of microtubules

Multiple cells from the same species were isolated, the relative cohesion protein content for each type was determined, and the results were plotted on the graph. Refer to the graph to answer the following question.

Which sample is consistent with a cell that has completed meiosis? 3

Which sample is consistent with a cell that is in metaphase I? 2

Which sample is consistent with a cell that is in telophase I? 1

Which sample is consistent with a cell that has completed mitosis? 3

Which sample is consistent with a cell that is entering mitosis? 2

Which of the following statements correctly describes the difference between the leading strand and the lagging strand in DNA replication?

The leading strand is synthesized in the 3'→ 5' direction in a discontinuous fashion, while the lagging strand is synthesized in the 5'→ 3' direction in a continuous fashion.

The leading strand is synthesized continuously in the 5'→ 3' direction, while the lagging strand is synthesized discontinuously in the 5'→ 3' direction.

The leading strand requires an RNA primer, whereas the lagging strand does not.

There are different DNA polymerases involved in elongation of the leading strand and the lagging strand.

The leading strand is synthesized continuously in the 5'→ 3' direction, while the lagging strand is synthesized discontinuously in the 5'→ 3' direction.

Referring to the figure below, what bases will be added as DNA replication proceeds on the bottom strand?

 

 

5′ C A G C A G A 3′

3′ T C T G C T G 5′

5′ A G A C G A C 3′

3′ G T C G T C T 5′

5′ A G A C G A C 3′

Considering that a new DNA strand can elongate only in the 5′ → 3′ direction. Use the figure below to mach the question to its answer.

 

Which of the four segments of new DNA (lighter blue) could be leading strands?

Which of the segments of new DNA (lighter blue) would be lagging strands, synthesized as a series of smaller Okazaki fragments?

B/C

A/D

Match the protein to its function in DNA replicatioin

DNA Poly 1: removes nucleotides from the RNA primer that is used for initiation DNA synthesis

Topoisomersase: relieves the strain in the DNA ahead of the replication fork caused by the untwisting of the double helix

DNA Poly 3: adds nucleotides to the 3' end of a growing DNA strand

DNA Ligase: plays role in the elongation of the lagging strand during DNA replication, joining Okazaki fragments together

Helicase: unwinds the DNA double helix at the replication fork

Signle-strand DNA binding protein: helps to hold the DNA strands apart while they are being replicated

Which of the labeled Okazaki fragments would be the first two to be synthesized? (The leading strands are nor shown)

 

A and F

C and B

D and C

A and B

D and C

Which of the following combinations of base pairs will be found in a molecule of DNA?

A = C

A = G and C = T

A + C = G + T

G + C = T + A

A + C = G + T

A sample of double-stranded DNA contains 42% cytosine. Approximately what percent of the nucleotides in this sample will be thymine?

8%

16%

42%

58%

8%

The sequence of nucleotides below is present at a DNA location where the chain opens to form a replication fork: 

3' C C T A G G C T G C A A T C C 5'

An RNA primer is formed starting at the underlined T (T) of the template. Which of the following represents the primer sequence?

 

5' A G C C U A G G 3'

5' A C G T T A G G 3'

5' A C G U U A G G 3'

5' A G C C T A G G 3'

5' A C G U U A G G 3'

The spontaneous loss of amino groups from adenine in DNA results in hypoxanthine, an uncommon base, opposite thymine. What combination of proteins could repair such damage?

nuclease, DNA polymerase, DNA ligase

helicase, primase, DNA polymerase

DNA ligase, helicase, single-strand binding protein

DNA ligase, replication fork proteins, adenylyl cyclase

nuclease, DNA polymerase, DNA ligase

A mutation in a gene called dnaB prevents the helicase from binding at the origin of replication. Which of the following events would you expect to occur as a result of this mutation?

Additional proofreading will occur.

No replication fork will be formed.

Replication will occur via RNA polymerase alone.

Replication will require a DNA template from another source.

No replication fork will be formed.