protien synthesis and transcription

Process of transcription

-Synthesis of mRNA using DNA as a template

-uses complementary base pairing (U,A,G,C)

-RNA polymerase forms bonds between RNA nucleotides

Process of translation

-Translation occurs on ribosomes when protiens are made

-the amino acid sequence of a protien is determined by the mRNA

-mRNA is determined by the order of bases of a DNA gene

-codons on mRNA corrospond to 1 amino acid on tRNA

-mRNA binds to a ribosome at the start codon

-tRNA transfers an amino acid to the ribosome

-tRNA moves to the next mRNA codon to continue the process, creating an amino acid chain until a stop codon is reached

-peptide bonds forms between 2 amino acids

What is the role of DNA polymerase?

-enzyme used to bond RNA nucleotides to form RNA

-acts as helicase does in DNA replication→ breaks the H bond between two strands of DNA

Complementary base pairing in RNA

-Adenine-Uracil

-Guanine-Cytosine

Three types of RNA

-messenger(mRNA): carries the message from the DNA to the ribosome

-transfer(tRNA): carries amino acids to the ribosomes

-Ribosomal(rRNA): builds ribosomes; made of a smaller and larger subunit

Define mutation

-Permanent change to DNA

-May change the protien structure and be heritable

-Sequence of DNA determines the amino acid sequence of the protien

-changing one base on the DNA can cause the mRNA to code for diffrent amino acids causing diffrent protiens to be made during translation

Point Mutation

A change in only one base of the gene

Define 3 main types of mutations

-Substition:One base is replaced by another

-Insertion: an additional base is addede

-Deletion: one base is removed

Define SNP using sickle cell anemia as an example

-gene sequence is altered by one letter

-consequence of SNP could be a diffrent amino acid which could have no or major impact

-sickle cell disease: SNP in hemoglobin could cause it to be sickle shaped

Describe the cause of Huntingtons Disease

-dominant mutation

-on chromosome 4 where CAG repeats multiple times

-This kind of mutation is known as a trinucleotide repeat expansion

-the mutated protien, mHtt, has a negative effect on brain cells causing symptoms

-CAG codes for glutamine

-The more glutamine the more severe the symptoms

-if a person has more than 40 repeats of CAG they will be affected

Define frameshift mutation and give an example

-Caused by an insertion or deletion in non-multiple pairs of 3

-This shift in bases could change the code completly or result in an early stop codon

-The delta 32 mutation of the CCR5 protien

-A person with the delta 32 mutation does not have a functioning protien receptor for HIV to bond too

Mutagen

-Chemicals that can cause a DNA mutation can sometimes modify the code and cause health issues such as cancer

Outline how mutation can lead to cancer

-Mutations are random changes in DNA

-Examples: Substitution, insertion, deletion of DNA bases

-Mutations can lead to uncontrolled cell division (mitosis)

-Abnormal cells develop and divide rapidly to form tumors

Homozygous

both alleles are the same such as TT or bb

Heterozygous

alleles are diffrent such as Tt or Bb

Dominant

capital letter, represses the recessive allele

Reccesive

Lowercase letter, can only be expressed in homozygous form

Genotype

The letters/alleles that represent the genes

Phenotype

expression of the genotype;physical description