Gene Expression Flashcards
are all genes expressed?
only a fraction of genes in a cell are expressed
describe 4 features of an RNA molecule:
it is a single stranded molecule
nucleotides containing ribose sugar, phosphate, base
found in nucleus and cytoplasm
bases include uracil pairs with adenine, guanine pairs with cytosine.
what is the role of RNA polymerase?
moves along DNA unwinding the double helix and breaking hydrogen bonds between the bases. RNA polymerase synthesises a primary transcript of mRNA from RNA nucleotides by complementary base pairing.
which process allows the formations of a mature mRNA transcript?
RNA splicing
what happens during RNA splicing?
the introns of the primary transcript are non-coding regions and are removed.
the exons are coding regions and are joined together to form the mature transcript
what is the function of tRNA?
it begins at a start codon and ends at a stop codon.
anticodons bond to codons by complementary base pairing.
what is gene expression?
it involves DNA sequences being transcribed and translated to make a protein.
describe what mRNA is?
it carries a copy of genetic code from the nucleus to the ribosome for protein synthesis.
describe what tRNA is?
each tRNA folds due to complementary base pairing. each of the tRNA molecule carries its specific amino acid to the ribosome
define alternative splicing:
different mature mRNA transcripts are produced from the same primary transcript depending on which exons are retained.
what are the key points of the protein structure:
proteins are made from amino acids and amino acids are linked by peptide bonds to form polypeptides.
polypeptide chains fold to form the three-dimensional shape of a protein which are help together by hydrogen bonds.
proteins have a large variety of shapes which determines their function.
