paper 1: DNA, Genes and Chromosomes, Proteinsynthesis Flashcards
draw and label a diagram of a DNA nucleotide
what does DNA stand for
deoxyribonucleic acid
describe how a strand of DNA forms
- many DNA nucleotides join together to make a DNA polynucleotide
- these are joined between the sugar moecule of one nucleotide and the phosphate of another nucleotide with a phosphodiester bond via a condensation reaction
describe how a DNA double helix forms
- bases from 2 strands form complementary base pairs joined together with hydrogen bonds
- the 2 strands twist and form a double helix
- the strands are anti-parallel
why can you describe DNA strands as being anti-parallel
DNA base sequence is read one way on one strand and the opposite way on the other strand
fill in this table
define a gene
DNA base sequence which codes for the amino acid sequence of a polypeptide
define a gene locus
fixed position on a particular DNA molecule/ chromsome which a gene occupies
define a genome
the complete set of genes in a cell
define a proteome
full range of proteins a cell is capable to produce
the genetic code is univeral. what does this mean
the same triplets code for the same amino acids in all living organsims
genetic code is non-overlapping. what does this mean
the DNA triplets do not share bases
genetcic code is degenerate. what does this mean
more than 1 triplet can code for the same amino acid
why might there be more codes than there are amino acids
- if there is a mutation in DNA then the amino acid sequence will be less likely to change so you still get a functional protein
how can a mutation in the DNA lead to a non-functioning protein or enzyme
- if there is a mutation in the DNA, this can change the primary structure of the protein
- can change the position of the hydrogen, ionic and disulfide bonds in the protien
- whihc changes the tertiary structure of the protein
- can lead to a non-functioning protein