Chromosomes Genes DNA Flashcards
What is DNA
Deoxyribonucleic acid.
Hereditary material in all living things.
A double helix structure formed by nucleotide pairs attached to a sugar phosphate backbone.
Deoxyribose sugar, phosphate group, nitrogen base
nucleotides base pair rule
A-T
C-G
form peptide bonds between them
What is a gene
A section of the DNA structure that codes for a particular protein which leads to a development of a feature.
chromosomes
made of DNA formed in the nucleus.
46 in humans 23 in egg and sperm
centromere the place where chromosome pairs intersect. p arm(short) and q arm(long)
DNA Replication
- polynucleotide strands of DNA separate.
- each strand acts as a template for formation of new DNA strand
- DNA polymerase assembles nucleotides into two new strands through base pairing rule
protein synthesis
transcription, translation
transcription
DNA in nucleus.
RNA polymerase splits a gene in the DNA. RNA polymerase forms single strand mRNA(messenger RNA) with free nucleotides in the nucleus no thymine replaced by uracil in RNA (base pair rules).
mRNA travels out of the nucleus through nucleus pores.
mutation
a change in the DNA of a cell. The wrong nucleotide can be used when making new DNA.
types of mutation: duplication, deletion, substitution, inversion
duplication
a nucleotide inserted twice instead of once. shifting the gene and coding a different protein
deletion
a nucleotide missed out
substitution
the wrong nucleotide is used. may have major effects where the cell can no longer function, or can do nothing as most amino acids can be coded in more than one way
inversion
a codon is inverted in order. may or may not affect the final protein
mutagens
ionising radiation(UV / X-rays / Gamma)
chemicals e.g. mustard gas, nitrous oxide, chemicals in cigarette smoke
