Download Major Functions

Introduction
to
Molecular Biology
Crash Course!
1 chromosome
=
1 DNA
molecule
Major Functions- DNA

Stores genetic information!

Expresses genetic
information when needed.

Replicates.

Doesn’t do any other
important cellular functions.
Major Functions- RNA

Middle Man.

DNA’s messenger boy.

Part-time building material.
Most of a cell (excluding the
water) is protein.
DOES THIS MAKE
SENSE??
Major Functions- Proteins

They execute nearly all cell functions.

They are a major building material.

They are enzymes, motors, receptors,
hormones, antibodies, cables, etc.
Central Dogma
What is a gene?

A gene is a stretch of DNA that contains
the information to produce a particular
product (usually a protein).
A gene produces a particular product
(usually a protein).
Transfer RNA
(tRNA)
Ribosomal RNA
(rRNA)
Messenger RNA
(mRNA)
PROTEIN
Transcription:
The enzyme RNA polymerase
unwinds and copies:
The mRNA and the DNA are base-pairing.
One strand is involved in transcription.
Next- Translation

How an mRNA produces a protein
DNA
Transcription
Cell
Cytoplasm
mRNA
Nucleus
Translation
Polypeptide
Fig. 9-3, p. 214
The genetic code is a triplet code.
Transfer RNA
Met
How many different codons are there??
Eukaryotic Gene Structure
Eukaryotic gene detail:
What is a mutation?
Explain why this mutation is different. It
is a synonymous mutation.
SNPs are not mutations.

Mutations are rare. Mutations are random.

SNPs are ancient differences and common.
Almost all common SNPs have only two
alleles. Many SNPs lie in the intergenic
regions (between the genes) or in introns.
Is the study of SNPs important?

SNPs may influence your susceptibility to a
wide variety of diseases.

At least that is what some people think!
The End