Chapter 6 vocab

Question 1

cancer

Answer 1

Disease caused by abnormal and uncontrolled cell proliferation, followed by invasion and colonization of body sites normally reserved for other cells.

Question 2

DNA ligase

Answer 2

Enzyme that reseals nicks that arise in the backbone of a DNA molecule; in the laboratory, can be used to join together two DNA fragments.

Question 3

DNA Repair

Answer 3

Collective term for the enzymatic processes that correct deleterious changes affecting the continuity or sequence of a DNA molecule.

Question 4

DNA replication

Answer 4

The process by which a copy of a DNA molecule is made.

Question 5

homologous recombination

Answer 5

Mechanism by which double-strand breaks in a DNA molecule can be repaired flawlessly; uses an undamaged, duplicated, or homologous chromosome to guide the repair. During meiosis, the mechanism results in an exchange of genetic information between the maternal and paternal homologs.

Question 6

lagging strand

Answer 6

At a replication fork, the DNA strand that is made discontinuously in short separate fragments that are later joined together to form one continuous new strand.

Question 7

leading strand

Answer 7

At a replication fork, the DNA strand that is made by continuous synthesis in the 5 -to-3 direction.

Question 8

mismatch repair

Answer 8

Mechanism for recognizing and correcting incorrectly paired nucleotides—those that are noncomplementary.

Question 9

mutation

Answer 9

A randomly produced, permanent change in the nucleotide sequence of DNA.

Question 10

nonhomologous end joining

Answer 10

A quick-and-dirty mechanism for repairing double- strand breaks in DNA that involves quickly bringing together, trimming, and rejoining the two broken ends; results in a loss of information at the site of repair.

Question 11

Okazaki fragment

Answer 11

Short length of DNA produced on the lagging strand during DNA replication. Adjacent fragments are rapidly joined together by DNA ligase to form a continuous DNA strand.

Question 12

primase

Answer 12

An RNA polymerase that uses DNA as a template to produce an RNA fragment that serves as a primer for DNA synthesis.

Question 13

proofreading

Answer 13

The process by which DNA polymerase corrects its own errors as it moves along DNA.

Question 14

replication origin

Answer 14

Nucleotide sequence at which DNA replication is initiated.

Question 15

Reading Frame

Answer 15

One of the three possible ways in which a set of successive nucleotide triplets can be translated into protein, depending on which nucleotide serves as the starting point.

Question 16

RNA (ribonucleic acid)

Answer 16

Molecule produced by the transcription of DNA; usually single-stranded, it is a polynucleotide composed of covalently linked ribonucleotide subunits. Serves a variety of structural, catalytic, and regulatory functions in cells.

Question 17

telomerase

Answer 17

Enzyme that elongates telomeres, synthesizing the repetitive nucleotide sequences found at the ends of eukaryotic chromosomes.

Question 18

telomere

Answer 18

Repetitive nucleotide sequence that caps the ends of linear chromosomes. Counteracts the tendency of the chromosome otherwise to shorten with each round of replication.

Question 19

template

Answer 19

A molecular structure that serves as a pattern for the production of other molecules. For example, one strand of DNA directs the synthesis of the complementary DNA strand.