DNA AQA AS BIOLOGY (BIOL2)

NOTES ON DNA and stuff

HideShow resource information
  • Created by: melissa
  • Created on: 08-04-12 14:40
Preview of DNA AQA AS BIOLOGY (BIOL2)

First 93 words of the document:

DNA
DNA (DEOXYRIBOSE) has a nucleotide structure consisting of
There are two different types of organic bases:
1) single ring bases- cytosine and thymine
2) double ring bases- adenine and guanine
The nucleotide structure forms by a condensation reaction
DNA STRUCTURE
DNA has a double helix structure which are joined together by hydrogen bonds.
Adenine always pairs with Thymine joined by 2 hydrogen bonds ( thymine two)
Guanine always pairs with Cytosine joined by 3 hydrogen bonds
These are said to be complementary to one another.

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

FUNCTION OF DNA
DNA is a very stable molecule which allows it to be passed from generation to generation without
change.
The two separate strands are joined with Hydrogen bonds which allows the to separate during DNA
replication
DNA is a very large molecule and so contains lots of genetic information
By having a double helix structure, the genetic material is slightly protected from becoming corrupt
THE TRIPLET CODE
Genes are sections of DNA that contain coded information for making polypeptides.…read more

Page 3

Preview of page 3

Here's a taster:

MEIOSIS
Meiosis produces four daughter cells. Each cell contains half the number of chromosomes as the
parent cells.
Meiosis involves two nuclear divisions:
first division
The homologous chromosomes pair up and their chromotids wrap around each other. Crossing over
occurs where portions of chromotids are exchanged
Each one of these chromosomes will go into one of the four daughter cells produced.
second division
the chromotids move apart.…read more

Page 4

Preview of page 4

Here's a taster:

THE REPLCATION OF DNA
DNA replicates by a process called semi-conservative replication
1. DNA helicase unzips the 2 strands of DNA
2. Free activated nucleotides are attracted to their complementary bases
3. DNA polymerase rejoins the strand
4.…read more

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all resources »