Download Genetic Information

Genetic Information
DNA
Deoxyribose nucleic acid
Job: stores genetic info
double helix
o looks like a twisted ladder
2 ribose sugars + 1 phosphate group
4 nucleotides (bases)
o complementary bases held together with a hydrogen
bond
will only bond with their complementary base
like a lock and a key
o adenine + thymine
o guanine + cytosine
if you know one strand you can figure out the other strand
o CGTTAACGTA
o GCAATTGCAT
DNA Replication
o Occurs during interphase, right before cell enters prophase
(mitosis and mitosis I)
Step 1
o DNA unzips & partially unwinds (only does a little at a time)
o Breaks Hydrogen bonds
Step 2
o Free nucleotides (floating in nucleus) find their complementary
base on the DNA strand
o Create a new hydrogen bonds
Step 3
o Keeps up the process until the entire chain is finished
o Rewinds and retwists
RNA
Ribose nucleic acid
Job: makes proteins
Single strand
1 ribose sugar + 1 phosphate group
4 nucleotides
o adenine + uracil
o Guanine + cytosine
3 types of RNA
o Messenger RNA (mRNA)
“reads” the genetic code (message) from the DNA
Transcription
RNA makes a copy of the DNA message
Message used to make proteins
 C A T T A G G C A T G (dna)
 G U A A U C C G U A C (rna)
o Transfer RNA (tRNA)
Transport rna code from mRNA to the ribosome
Acts like a taxi
o Ribosomal RNA (rRNA)
Makes proteins in the ribosome
Translation
Protein synthesis
Mutations
Point Mutation
Small change, usually unnoticeable in an organism
Change a single base pair, the wrong things bond
o THE DOG BIT THE CAT
o THE DOG BIT THE CAR
Frameshift mutation
A new amino acid (base pair) is inserted into an entire codon
All other codons shifted out of place
THE DOG BIT THE CAT
THE DOB ITT HEC AT
Chromosomal mutations
Bits of DNA break off and change their location
Common in plants
o Get variation
Mutagens
What causes mutations, can lead to cancer
o High radiation, chemicals, high temperature
Anything that can damage the cell
DNA can fix itself, but if it is constantly exposed to a
mutagen (ex. smoking) then it will not be able to fix
the mutation
Can result in cancer (cell keeps dividing) or in cell
death (get enough cell death, the organism dies)