GCD Exam 1 Chapter 5

DNA Double helix is made of

Two anti parallel strands and held between hydrogen bonds between the complementary base pairs

Phosphidiestar bon

5 prime ( carbon end) to 3 prime (oxygens)

Negatively charged

5 prime of PO4-groups

A single strand

Contains information needed to replicate DNA

Each DNA molecule

5 carbon sugar, nitrogen containing base and sugar phosphate backbone

Chromosomes

1 double strand DNA molecule

Histones

Positively charged proteins——> bind negatively charged DNA

DNA wraps ____ around histone octamer to form a nucleosome

147 bp

Histone H1

bind the linker to DNA and help fold chromatin into the 30 nm fiber

N Terminal Tail

acetylation, methylation, phosphorylation

Histone H3

Can promote heterochromatin

Histone H3 and N terminal

Modified to lead to Gene Silencing

Chromatin remodeling

Use atp hydrolysis to reposition to nucelosome