Ch. 16 Vocab

Question 1

a virus that infects bacteria; aka a phage

Answer 1

bacteriophages

Question 2

the form of native DNA, referring to its two adjacent antiparallel polynucleotide strands wound around an imaginary axis into a spiral shape

Answer 2

double helix

Question 3

type of DNA replication in which the replicated double helix consists of one old strand, derived from the old molecule, and one newly made strand

Answer 3

semiconservative model

Question 4

site where the replication of a DNA molecule begins, consisting of a specific sequence of nucleotides

Answer 4

origins of replication

Question 5

a Y-shaped region on a replicating DNA molecule where the parental strands are being unwound and new strands are growing

Answer 5

replication fork

Question 6

an enzyme that untwists the double helix of DNA at the replication forks, separating the two strands and making them available as template strands

Answer 6

helicases

Question 7

a protein that breaks, swivels, and rejoins DNA strands; helps relieve strain in the double helix ahead of the replication fork during DNA replication

Answer 7

topoisomerase

Question 8

a short stretch of RNA with a free 3’ end, bound by complementary base pairing to the template strand, that is elongated with DNA nucleotides during DNA replication

Answer 8

primer

Question 9

an enzyme that catalyzes the elongation of new DNA by the addition of nucleotides to the 3’ end of an existing chain

Answer 9

DNA polymerases

Question 10

the new complementary strand synthesized continuously along the template strand toward the replication fork in the mandatory 5’–>3’ direction

Answer 10

leading strand

Question 11

a discontinuously synthesized DNA strand that elongates by means of Okazaki fragments, each synthesized in a 5’–>3’ direction away from the replication fork

Answer 11

lagging strand

Question 12

a short segment of DNA synthesized away from the replication fork on a template strand during DNA replication, many of which are joined together to make up the lagging strand of newly synthesized DNA

Answer 12

Okazaki fragments

Question 13

a linking enzyme essential for DNA replication; catalyzes the covalent bonding of the 3’ end of one DNA fragment to the 5’ end of another DNA fragment

Answer 13

DNA ligase

Question 14

an enzyme that cuts DNA or RNA, either removing one or a few bases or hydrolyzing the DNA or RNA completely into its component nucleotides

Answer 14

nuclease

Question 15

the tandemly repetitive DNA at the end of a eukaryotic chromosome’s DNA molecule that protects the organism’s genes from being eroded during successive rounds of replication

Answer 15

telomeres

Question 16

a dense region of DNA in a prokaryotic cell

Answer 16

nucleoid

Question 17

the complex of DNA and proteins that makes up a eukaryotic chromosome; exists as a mass of very long, thin fibers when the cell isn’t dividing

Answer 17

chromatin

Question 18

the conversion of a normal animal cell to a cancerous cell; a change in genotype and phenotype due to the assimilation of external DNA by a cell

Answer 18

transformation