Inheritance paper 1

genome

the entire DNA of an organism

DNA description (4)

macromolecule, made of nucleotides, double helix, 2 strands

structure of DNA (3)

phosphate - pentose sugar - base

gene

section of DNA that codes for the production of a protein

where are genes found

on the chromosome in the nucleus

alleles

different version of the same gene

mutation

change in the order of bases leading to a different codon

how can a mutation affect the phenotype

different codon leads to coding for another protein or could change the active site of the enzyme so no longer fits properly (not functional)

chromosome

DNA wrapped around a protein - carries genetic information

homologous pair

pair of chromosomes that carry genes controlling the same features

diploid

cells making up body - 46 chromosomes

haploid

found in gametes - contain one chromosome from each homologous pair - 23 chromosomes

inheritance

transmission of genetic information

genotype

collection of genes an organism has

phenotype

observable characteristics from genotype

homozygous

alleles are identical - AA or aa

heterozygous

alleles are different - Aa

mitosis

cell division that produces diploid body cells for growth and repair of tissues, identical sets of chromosomes

meiosis

cell division that produces haploid cells - gametes

most phenotypic features are the result of…

multiple different genes interacting rather than a single gene inheritance

who is responsible for the sex of the baby

father is - as it depends on whether the sperm which fuses with the egg has an x or y chromosome

random fertilisation increases

genetic variation

mutations occur more frequently due to … (2)

ionising radiation, chemical mutagens

natural selection 6 marker answer

there is variation within a population due to a random mutation

conditions of the environment may suit this allele or a selective pressure will arise

if the new allele helps

then individual will live to reproduce and pass the allele

over time frequency of allele increases as it is passed down generations

Bacteria sometimes develop random mutations in their DNA which can result …

in the bacteria being less affected by the antibiotic and as bacteria multiplies quickly number of ones resistant increases - this is called antibiotic resistance strain

Antibiotic resistance strain cycle can be repeated until …

bacteria is resistant to loads of antibiotics - these are called superbugs

example of a superbug

MRSA