BIOS 1700 Exam 5 Missed Study Questions

Which factors make amplification of a DNA fragment by means of the polymerase chain reaction possible? Select all that apply.

-DNA polymerase elongates a growing DNA strand by the addition of successive deoxynucleotides to the 3' end. -Complementary single-stranded nucleic acid sequences can come together to form a duplex molecule.

Which factors make sequencing by the Sanger chain-termination method possible? Select all that apply.

-New nucleotides are added only to the 3' end of a growing DNA strand. -Duplex nucleic acid molecules can be separated by size by means of gel electrophoresis. -Complementary single-stranded nucleic acid sequences can come together to form a duplex molecule. -A DNA strand whose 3' end terminates in a dideoxynucleotide cannot be elongated.

Most of the cells examined during interval C were in:

G2 phase.

Which of the statements is true when a cell has a mutation in the p53 gene, such that the p53 protein is not able to be phosphorylated?

The cell would proceed through the cell cycle even in the presence of DNA damage.

In gel electrophoresis, DNA fragments migrate toward the negative pole of the electric field.

false

A cell in prophase I of meiosis has _____ as many copies of chromosomes as each of the daughter cells following cytokinesis of meiosis II.

four times

In contrast to linear DNA replication, circular DNA replication typically:

has a single origin of replication.

Which one of the choices would most likely contribute to uncontrolled cell proliferation (that is, cancer)?

a mutant CDK that was active in the absence of its cyclin binding partner

A gene associated with promoting normal cell division is called:

a proto-oncogene.

CDKs are important in the regulation of the cell cycle. They carry out their function by:

adding phosphate groups to target proteins.

During what step in meiosis do homologous chromosomes separate?

anaphase I

Cancers develop stepwise over time because:

it takes multiple mutations of multiple genes to allow cancer cells to develop.

An enzyme that catalyzes the addition of a phosphate group from ATP to another molecule is called a:

kinase.

Homologous chromosomes separate from each other in:

meiosis I.

You are interested in studying human ß-globin and decide to produce the protein in bacterial cells. The ß-globin gene is a relatively simple gene with a single intron. You insert the entire gene, including the gene's promoter, in a plasmid and transform the recombinant plasmid into E. coli. You are disappointed to discover that your bacterial culture does not produce the correct protein. What are some possible explanations? Select all that apply.

-The bacterial cell cannot splice introns. -The bacterial cell does not recognize the eukaryote promoter. -The bacterial cell produces the protein, but the protein is rapidly degraded

Which events would happen to a cell if cyclin levels were always high in the cell? Select all that apply.

-The cell would divide rapidly. -Protein substrates of CDKs would be constantly phosphorylated.

The second meiotic division resembles mitosis because:

-chromosomes decondense during telophase II. -sister chromatids are separated during anaphase II to become the chromosomes of the daughter cells. -spindle microtubules attach from opposite directions to the centromere of each sister chromatid pair. -the daughter cells have the same number of chromosomes as the parent cell.

Which stages of mitosis are correctly matched with the events that occur in the stage? Select all that apply.

-cytokinesis; a contractile ring of actin filaments forms at the cell equator -metaphase; chromosomes line up in the middle of the cell

Given that the rate of DNA synthesis of a plasmid in yeast is 50 nucleotides per second and the circular plasmid replicates in 20 minutes, what is the approximate maximum size of the plasmid?

120,000 bp

Consider a diploid organism with a haploid complement of 4 chromosomes in its gametes. At meiotic prophase I, how many total chromosomes copies will be present in a cell?

16; 4 pairs of homologous chromosomes and 2 sister chromatids per chromosome

A new nucleotide can only be added to the _____ end of a growing DNA strand. DNA therefore always grows in the _____ direction.

3'; 5' to 3'

The leading strand is the daughter strand that has its _____ end pointed toward the replication fork and is therefore synthesized _____.

3'; continuously

How many copies of each gene are present in human skin cells at G2 of interphase?

4

During DNA replication in a cell, RNA primase synthesizes a primer that is complementary to the region in the sequence shown in bold: 5'-CACAGCAGAAACCTACTCATG-3' What is the primer sequence?

5'-GUUGUAGGUUUC-3'

What primer sequences would you use? 5'-ATGCTGAAACTTCTC···GGGATGAAATCAGTTT-3 '3'-TACGACTTTGAAGAG···CCCTACTTTAGTCAAA-5'

5'-TGAAAC-3' and 5'-CTGATT-3'

The lagging strand is the daughter strand that has its _____ end pointed toward the replication fork and is therefore synthesized _____.

5'; in a series of segments

At the start of mitosis, how many sister chromatids are present in a human cell?

92

In what way is cytokinesis in plant cells similar to binary fission in a bacterium?

Cell wall material is deposited to separate the daughter cells.

Which of the statements might explain hemophilia in a girl born to parents with normal blood clotting phenotypes?

Nondisjunction during sperm formation resulted in her receiving no sex chromosome from her father and an X chromosome from her mother; she is XO.

Which of the statements about viruses is true?

None of the other answer options is correct.

The transformation step in creating bacteria genetically engineered to produce human proteins involves:

bacteria taking up the recombinant DNA in the form of the vectors.

The technique of Sanger sequencing takes advantage of the fact that dideoxynucleotides (nucleotides in which the 3' hydroxyl group is absent) act as:

chain terminators.

Which of these is necessary for the first step of PCR?

original template DNA

The extrachromosomal DNA often found in bacteria is called a:

plasmid

The correct sequence of steps in the M phase of the cell cycle is:

prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis.

In a long DNA molecule, each origin of replication produces a _____ with a _____ on each side.

replication bubble; replication fork

What process can account for the phenomenon wherein a normal XY male produces a sperm carrying two Y chromosomes?

second-division nondisjunction

During meiosis I:

sister chromatids are not separated.

If you were able to find a drug that could inhibit the reactivation of telomerase activity in cancer cells, the cancer cells would:

slowly erode their chromosome ends.

In replication of a linear double-stranded DNA molecule, one end of each strand becomes shorter in each round of replication. This happens because:

the RNA primer cannot be replaced at the very end of a lagging DNA strand.

What feature of double-stranded DNA makes it necessary to have a leading strand and a lagging strand during replication?

the antiparallel orientation of the strands

Phosphorylated p53 is a protein that accumulates in the nuclei of cells that have damaged DNA where it functions to block the cell cycle and activate DNA repair. The p53 gene that encodes this protein is an example of a(n):

tumor suppressor gene

p53 is an example of a(n):

tumor suppressor.

When we say that DNA replication is semiconservative, we mean that:

when DNA is replicated each new double helix contains one parental strand and one newly synthesized daughter strand.