Dna

Front 1

DNA

Back 1

DNA is the molecule responsible for containing all our genetic information

Front 2

DNA experiments

Back 2

There were 4 main sets of experiments

1) 1943 - Joachim Hammerling
- the nucleus contained instructions for the algae's growth

2) 1928 - Frederick Griffith
- some chemical in dead S form could change R form into S form

3) 1944 - Oswald Avery, Maclyn McCarty
- DNA from S form cells could change R form cells into S form cells

4) 1952 - Alfred Hershey, Martha Chase
- viruses inject DNA into bacteria, and as thus DNA contains genetic instructions

Front 3

Structure of DNA

Back 3

DNA is...
- a deoxyribonucleic acid
- made of chains of nucleotide (a type of sugar where a nitrogen base is attached to 1 carbon, and a phosphate group is attached to another)

Front 4

Types of Nucleotide

Back 4

1. Adenine (A)
2. Guanine (G)
3. Thiamine (T)
4. Cytosine (C)

Front 5

Pairing

Back 5

Adenine (A) forms hydrogen bonds with Thiamine (T)

Guanine (G) forms hydrogen bonds with Cytosine (C)

A<--->T
G<--->C

Front 6

Continued

Back 6

- prior to mitosis or meiosis, DNA must be replicated
-to achieve this, the DNA molecule is pulled apart into 2 strands
-each strand acts as a template to build complementary strand
-this is called semiconservative replication

Front 7

DNA Helicase

Back 7

-an enzyme that pulls apart the 2 strands of DNA
-works by breaking hydrogen bonds
-the area where the 2 strands are being pulled apart is called the replication fork

Front 8

DNA polymerase III

Back 8

-builds complimentary strands to the unzipped DNA molecule
-DNA polymerase III works by linking together free nucleotids that are complimentary to the template strands
-first a single stranded piece of RNA called a primer is attached to the template strand

Front 9

DNA polymerase continued...

Back 9

-works in 1 direction: it adds nucleotides 5' to 3'
-this results in one of the strands to be built continuously (the leading strand) while the other is built in pieces (the lagging strand)
-the short strands of DNA produced on the lagging strand are called are called Okazaki fragments

Front 10

DNA polymerase I
DNA ligase

Back 10

-After DNA polymerase III lays down complimentary nucleotides, 2 more enzymes have jobs to do
-DNA polymerase I, replaces the RNA primers with appropriate strands of DNA
-DNA ligase "glues" together all the DNA strands
-both DNA polymerase I and III proofread newly synthesized strands of DNA
-When a mistake is found, they cut out the incorrect nucleotide and place in the correct one

Front 11

Gene Expression

Back 11

-DNA codes for proteins
-the 4 different nucleotides are like letters in the alphabet
-Step 1: strands of DNA are transcribed into RNA
-Step 2: the RNA is translated into proteins

Front 12

RNA

Back 12

-another type of nucleic acid
-ribonucleic acid
-single stranded
-the sugar has an extra oxygen
-4 types: guanine (G), cytosine (C), adenine (A), uracil (U)

Front 13

DNA and RNA example

Back 13

DNA: 5' TAGCCGA 3'
RNA: 3' AUCGGCU 5'
DNA-RNA
A U
C G
T A
G C

Front 14

Transcription

Back 14

1st step in gene expression
DNA is transcribed into messenger RNA (mRNA)
3 steps in transcription: initiation, elongation, termination

Front 15

Initiation

Back 15

-RNA polymerase binds to a segment of DNA called the promoter, and opens the double helix
-the promoter is a region of DNA that RNA polymerase recognizes as a starting point
-promotes are found