KA3 Gene Expression Flashcards
What are the structure of proteins
Proteins are chains of amino acids
The amino acids bond together by peptide bonds to form polypeptide chains
The sequence of amino acids determines the structure and function of the proteins made
What are stages 1 2 and 3 of translation
1- the ribosomes bind at the mRNAs start codon
2- hydrogen bonds form between the mRNA codons and the anticodons on tRNA molecules by complementary base pairing- each tRNA carries a specific amino acid
3- tRNA continues to bring amino acids and aligning them in a sequence
What are stages 4 and 5 of translation
4- peptide bonds form between adjacent amino acid and tRNA is then released for reuse
5-the chain of amino acids is now called a polypeptide chain
When the stop codon is reached on the mRNA transcript the polypeptide chain is released from the ribosome
What is translation
Transfer RNA
tRNA is involved in the translation of mRNA into a polypeptide chain at ribosome
tRNA are going freely floating in the cytoplasm of cells
What is alternative RNA splicing
one gene many proteins
Different proteins can be expressed from 1 gene as a result of alternative RNA splicing
Different mature mRNA transcripts are produced depending on the exons
What are structural or fibrous proteins
Found in many places including cell membranes and have lots of roles
2 structural proteins, actin + myosin control muscle contractions
Keratin makes up hair and collagen provides skin elasticity
What is RNA splicing
not all primary mRNA transcript is useful
Introns- non coding regions are cut out and removed
Exons- coding regions are spliced together to form a mature mRNA transcript
The mature mRNA is then passed out the nucleus to the cytoplasm
What are the 2 stages of gene expression
Transcription
Translation
What is rRNA
Combined with the protein to make up the structure of a ribosome
What is mRNA
Carries a complementary copy of the code from a gene on the DNA strand to a ribosome for translation
What is tRNA
Carries a specific AA to the to the ribosome where they can be assembled into a polypeptide chain
What are the 3 types of RNA
Messenger mRNA
Transfer tRNA
Ribosomal rRNA
What is the differences of RNA and DNA
RNA single stranded Uracil Ribose sugar Found in nucleus + cytoplasm
DNA double stranded Thymine Deoxyribose sugar Only found in nucleus
What is required for transcription
RNA polymerase
DNA template
Free nucleotides
Start/stop codon
What is transcription
When mRNA is made form DNA
