Chapter 15 Flashcards Preview

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Flashcards in Chapter 15 Deck (27):
1

capsid

A shell of protein enclosing the genome of a virus particle.

2

complementary base pairing

The association between specific nitrogenous bases of nucleic acids stabilized by hydrogen bonding. Adenine pairs only with thymine (in DNA) or uracil (in RNA), and guanine pairs only with cytosine.

3

daughter strand

The strand of DNA that is newly replicated from an existing template strand of DNA.

4

deoxyribonucleoside triphosphate (dNTP)

A monomer used by DNA polymerase to polymerize DNA. Consists of the sugar deoxyribose, a base (A, T, G, or C), and three phosphate groups.

5

DNA helicase

An enzyme that breaks hydrogen bonds between nucleotides of DNA, "unzipping" a double-stranded DNA molecule.

6

DNA ligase

An enzyme that joins pieces of DNA by catalyzing the formation of a phosphodiester bond between the pieces.

7

DNA polymerase

Any enzyme that catalyzes synthesis of DNA from deoxyribonucleotide triphosphates (dNTPs).

8

double helix

The secondary structure of DNA, consisting of two antiparallel DNA strands wound around each other.

9

genome

All the hereditary information in an organism, including not only genes but also stretches of DNA that do not contain genes.

10

lagging strand

In DNA replication, the strand of new DNA that is synthesized discontinuously in a series of short pieces that are later joined. Also called discontinuous strand. Compare with leading strand.

11

leading strand

In DNA replication, the strand of new DNA that is synthesized in one continuous piece. Also called continuous strand. Compare with lagging strand.

12

mismatch repair

The process by which mismatched base pairs in DNA are fixed.

13

nucleotide excision repair

The process of removing a damaged region in one strand of DNA and replacing it with the correct sequence using the undamaged strand as a template.

14

Okazaki fragment

Short segment of DNA produced during replication of the lagging strand template. Many Okazaki fragments make up the lagging strand in newly synthesized DNA.

15

origin of replication

The site on a chromosome at which DNA replication begins.

16

parental strand

A strand of DNA that is used as a template during DNA synthesis.

17

primase

An enzyme that synthesizes a short stretch of RNA to use as a primer during DNA replication.

18

primer

A short, single-stranded RNA molecule that base-pairs with a DNA template strand and is elongated by DNA polymerase during DNA replication.

19

proofreading

The process by which a DNA polymerase recognizes and removes a wrong base added during DNA replication and then continues synthesis.

20

replication fork

The Y-shaped site at which a double-stranded molecule of DNA is separated into two single strands for replication.

21

replisome

The macromolecular machine that copies DNA; includes DNA polymerase, helicase, primase, and other enzymes.

22

semiconservative replication

The way DNA replicates, in which each strand of an existing DNA molecule serves as a template to create a new complementary DNA strand. It is called semiconservative because each newly replicated DNA molecule conserves one of the parental strands and contains another, newly replicated strand.

23

single-strand DNA-binding proteins (SSBP)

A protein that attaches to separated strands of DNA during replication or transcription, preventing them from re-forming a double helix.

24

telomerase

An enzyme that adds DNA to the ends of chromosomes (telomeres) by catalyzing DNA synthesis from an RNA template that is part of the enzyme.

25

telomere

The end of a linear chromosome that contains a repeated sequence of DNA.

26

topoisomerase

An enzyme that prevents the twisting of DNA ahead of the advancing replication fork by cutting the DNA, allowing it to unwind, and rejoining it.

27

xeroderma pigmentosum (XP)

A human disease characterized by extreme sensitivity to ultraviolet light. Caused by an autosomal recessive allele that inactivates the nucleotide excision DNA repair system.