topic 6 DNA Transcription and Translation

dna/deoxyribonucleic acid

made and found in the nucleus, is a polymer of DN’s

what are the three groups of DNA?

phosphate group, sugar, and nitrogenous base

what are DNA’s four bases?

adenine, thymine, guanine, cytosine

dehydration

when a nucleotide is joined via its phosphate group and the hydroxyl (O-H) on the 3’ carbon and continues to grow in the 3’ direction

5’ → 3’ direction rule thing

sugar-phosphate is backbone, nitrogenous base is like the appendage whose sequence varies gene to gene/allel to allele

chargaffs rule

states that number of adenine = number of thymine and number of guanine = cytosine in DNA

franklins photo

provided xray diffraction pattern of DNA, it showed the width of a chromosome

winston and cricks double helix

used chargaffs rule and franklins photos to create a model of DNA with two reverse, complimenting strands with H-bonds holding them together

semiconservative model

the hydrogen bond positions make adenine go the thymine and guanine go to cytosine

process of dna replication

1. helicase unzips

2. single stranded bonding proteins keep the strand from sticking together

3. primase puts down an RNA primer

4. DNA polymerase goes to the primer and put DNA down towards 3’

DNA polymerase

proofreads and removes RNA primers on the lagging strand

process of transcription

1. initiation- polymerase recognizes and binds to promoter sequence and RNAP unzips DNA

2. elongation- transcript is built in the 5’ → 3’ direction

3. termination- transcript separates and DNA is rezipped

tRNA

transfer DNA

rRNA

ribosomal RNA, makes RNA molecules to make ribosomes

mRNA

protein coding gene

5’ cap and 3’ tail

facilitate binding of mRNA to ribosome and protects edge of transcript

genetic code

triples of mRNA nucleotides called codons which encode amino acids or stop codons

translation process

1. initiation

2. elongation- chain of amino acids gets longer

3. termination- stop codon