Biology Chapter 16

Front 1

Chargaff's Rule

Back 1

in any species there is an equal number of A and T bases, and an equal number of G and C bases

Front 2

Origins of Replication

Back 2

*where replication begins.
Where the 2 DNA strands are separated, opening up a replication bubble.

Front 3

Helicases

Back 3

enzymes that untwist the double helix at the replication forks

Front 4

Single Strand Binding Protein

Back 4

binds to and stabilizes single stranded DNA until it can be used as a template.

Front 5

Topoisomerase

Back 5

corrects "overwinding" ahead of replication forks by breaking, swiveling and rejoining DNA strands.

Front 6

Primer

Back 6

initial nucleotide strand

Front 7

DNA polymerase III

Back 7

using parental DNA as a template, synthesizes new DNA strand by covalently adding nucleotides to the 3' of a pre-existing DNA strand or RNA primer

Front 8

DNA polymerase I

Back 8

removes RNA nucleotides of primer from 5' end and replaces them with DNA nucleotides

Front 9

DNA ligase

Back 9

joins 3' end of DNA that replaces primer to rest of leading strand and joins okazaki fragments of lagging strand

Front 10

Telomeres

Back 10

postpone the erosion of genes near the ends of DNA molecules
*nucleotide sequences

Front 11

Telomerase

Back 11

catalyzes the lengthening of telomeres in germ cells

Front 12

Chromatin

Back 12

a complex of DNA and protein, and is found in the nucleus of eukaryotic cells

Front 13

Histones

Back 13

proteins that are responsible for the first levels of DNA packing in chromatin

Front 14

Euchromatin

Back 14

loosely packed chromatin

Front 15

Heterochromatin

Back 15

a few regions of chromatin that are highly condensed (telomeres and centromeres)
*happens during interphase