ch. 11 review quiz

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

- each replicated DNA strand requires an RNA primer. - DNA polymerase elongates a growing DNA strand at only the 3′ end. - the RNA primer cannot be replaced at the very end of a DNA strand.

Sexual reproduction results in an increase in genetic diversity because

- of both recombination during prophase I and random orientation of bivalents during metaphase I. - during metaphase I, the bivalents line up in a random orientation so that gametes inherit a random set of maternally and paternally derived chromosomes. - during fertilization, the gametes that fuse are random so that a large number of chromosomal combinations are possible in the new organism. - during prophase I, genes that are paternally and maternally derived are recombined on the chromosomes so that the gametes have chromosomes that are different from the parents' chromosomes. * All of these choices are correct. *

When do sister chromatids separate in meiosis?

Anaphase 2

Which enzyme is the first to bind to the DNA sequences at the origin of replication?

DNA helicase

Refer to the figure shown. What important difference is there between meiosis in males and females?

The division of cytoplasm differs between males and females.

To cells that are defective in primer removal, you add fluorescent ribonucleotides when the cells are undergoing DNA replication. In this case, you observe that one strand glows more than the other not only near the replication fork but also at intervals along its length. Which strand glows in this way and why?

The lagging strand slows in this way because its RNA primers are required for each Okazaki fragment and are closely spaced

Why are telomeres a necessary component of linear chromosomes?

They maintain the length of a chromosome because DNA is shortened every time it is replicated.

The alignment of chromosomes at metaphase of meiosis II is most similar to the alignment of chromosomes during metaphase of mitosis.

True

How does meiosis generate genetic diversity?

both crossing over at prophase I and random alignment of homologs at metaphase I

At the end of mitosis, the daughter cells are _____, whereas at the end of meiosis the daughter cells are _____.

diploid; haploid

Telomerase activity in stem cells is very low.

false

Polar bodies are

haploid cells

Homologous pairs of chromosomes separate during:

meiosis 1 only

During meiosis, genetic variability is introduced during which phase?

metaphase 1

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

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

Energy is required in order to add a nucleotide to the growing strand of DNA during replication. From where does that energy come?

the incoming nucleotide

A daughter strand of DNA produced during chromosome replication can be composed of leading and lagging strands from different replication bubbles.

true

During meiosis, two rounds of DNA synthesis are required to form four gametes from one parent cell.

true

Stem cells located in the gastrointestinal tract would possess more active telomerase compared to the amount of telomerase activity in mature neurons of the brain.

true