AP Biology Spring Semester Concept Summary

DNA

Nucleic acid made up of nucleotides, genetic blueprint of life, composed of two complementary antiparallel strands running 3' to 5' making a double helix

Backbone of DNA

Deoxyribose sugar and phosphate connected by phosphodiester bonds

Rungs

nitrogen bases pairs hydrogen bonded together

Base pairs of DNA

Adenine, Thymine, Guanine, Cytosine

Genes

Code specifically for polypeptides, located on chromosomes

Genome

All the DNA in one cell of an organism

two

Number of copies made of the DNA during replication prior to cell division

First step of DNA replication

the DNA double helix is "unzipped" or separated when an enzyme breaks hydrogen bonds between nitrogen bases

Second step of DNA replication

Topoisomerase reduce supercoiling ahead of the replication fork

Third step of DNA replication

RNA primase places an RNA primer down in the template strands

Fourth step of DNA replication

DNA polymerase reads the DNA base pairs of a strand as a template and lays down complementary nucleotides to generate a new complementary partner strand

Fifth step of DNA replication

Replication proceeds continuously on the leading strand

Sixth step of DNA replication

The lagging strand forms with Okazaki fragments, which must be joined later by DNA ligase