DNA Structure and Protein Synthesis Overview

Purines

Adenine and Guanine

Pyrimidines

Cytosine and Thymine

DNA Helicase

The enzyme that unwinds the DNA strands during replication.

DNA Polymerase

Adds new nucleotides and proofreads the strand.

Semi-conservative replication

The replication process where each new DNA molecule consists of one old strand and one new strand.

Transcription

The first step of protein synthesis.

Nucleus

Where transcription occurs.

mRNA

Carries the genetic code from DNA to the ribosome.

Translation

The process that occurs at the ribosome to build proteins.

Frameshift mutation

An extra base is inserted or deleted, shifting the reading frame.

Silent mutation

A mutation that has no effect on protein structure.

Hydrogen bonds

What holds the two strands of DNA together.

3 Parts of a Nucleotide

A sugar (a 5-carbon deoxyribose), a phosphate group, and a nitrogenous base (4 types).

Deletion

Removes a chromosomal segment

Duplication

repeats a segment

Inversion

reverses a segment within a chromosome

Translocation

Moves a segment from one chromosome to another, non-homologous one.

RNA Editing

mRNA can be changed before they leave the nucleus

Introns

Nucleotides that interfere with the sequence and are removed

Exons

Nucleotide that are spliced back together and exit the nucleus