Genetics Chap 6

Front 1

deoxyribose

Back 1

The five-carbon sugar present in DNA.

Front 2

dideoxyribose

Back 2

A deoxyribose sugar lacking the 3'' hydroxyl group; when incorporated into a polynucleotide chain, it blocks further chain elongation.

Front 3

DNA ligase

Back 3

An enzyme that catalyzes formation of a covalent bond between adjacent 5''-P and 3''-OH termini in a broken polynucleotide strand of double-stranded DNA.

Front 4

DNA polymerase

Back 4

Any enzyme that catalyzes the synthesis of DNA from deoxynucleoside 5''-triphosphates, using a template strand.

Front 5

DNA replication

Back 5

The semiconservative copying of a DNA molecule.

Front 6

editing function

Back 6

The activity of DNA polymerases that removes incorrectly incorporated nucleotides; also called the proofreading function.

Front 7

exonuclease

Back 7

An enzyme that removes a terminal nucleotide in a polynucleotide chain by cleavage of the terminal phosphodiester bond; nucleotides are removed successively, one by one; usually specific for either DNA or RNA and for either single-stranded or double-stranded nucleic acids.

Front 8

gyrase

Back 8

A type of topoisomerase II that cleaves and rejoins both strands of a DNA duplex to relieve torsional stress.

Front 9

lagging strand

Back 9

The DNA strand whose complement is synthesized in short fragments that are ultimately joined together.

Front 10

leading strand

Back 10

The DNA strand whose complement is synthesized as a continuous unit.

Front 11

megabase (Mb)

Back 11

Unit of length of a duplex nucleic acid molecule; equal to 1 million base pairs.

Front 12

nucleotide

Back 12

A nucleoside phosphate.

Front 13

Okazaki fragment

Back 13

Any of the short strands of DNA produced during discontinuous replication of the lagging strand; also called a precursor fragment.

Front 14

primer

Back 14

In nucleic acids, a short RNA or single-stranded DNA segment that functions as a growing point in polymerization.

Front 15

purine

Back 15

A class of organic base found in nucleic acids; the predominant bases are adenine and guanine.

Front 16

replication origin

Back 16

The base sequence at which DNA synthesis begins.

Front 17

restriction map

Back 17

A diagram of a DNA molecule showing the positions of cleavage by one or more restriction endonucleases.

Front 18

semiconservative replication

Back 18

The usual mode of DNA replication, in which each strand of a duplex molecule serves as a template for the synthesis of a new complementary strand, and the daughter molecules are composed of one old (parental) and one newly synthesized strand.

Front 19

theta replication

Back 19

Bidirectional replication of a circular DNA molecule, starting from a single origin of replication.

Front 20

Watson-Crick base pairing

Back 20

Base pairing in DNA or RNA in which A pairs with T (or with U in RNA) and G pairs with C.