inheritance condensed Flashcards
gamete
organisms reproductive cell which has half the number of chromosomes
genome
entire DNA of an organism
chromosome
strucutr found in the nucleus made up of long strands of DNA
Gene
short section of DNA which codes for a protein and contributes to a characteristic.
allele
different forms of a gene
dominant allele
only one is needed for it to be expressed and for the corresponding phenotype to be observed
recessive allele
2 copies are needed for it to be expressed and for the corresponding phenotype to be observed
homozygous
when both inherited alleles are the same
heterozygous
when both inherited alleles is dominant and recessive
genotype
the combination of alleles an individual has
eg. Aa
phenotype
physical characteristics that are observed in the invidual, result of polygenic inheritance
codominance
when neither allele in dominant over the other, so they both contribute to the phenotype
what does DNA stand for
deoxyribonucleic acid
what is DNA made from
2 strands- double helix
polymer
what is a nucleotide made from
one sugar
one phosphate group
one 4 different organic bases
What codes for an amino acid
Three bases
what are chromosomes made from
structures of long molecules of DNA
mitosis
one cell divdes to from 2 identical daughter cells
phase 1 of mitosis
interphase
- 46 chromosomes are replicate
stage 2 mitosis
- chromosomes line up at the equator of the cell
- spindle fibres pull each chromosome of the X to either sides
stage 3 mitosis
- two identical cells form when a cytoplasm and cell membrane divde, each containing 46 chromosomes.
when does mitosis occur
growth and development, replacing damaged cells, cloning.
meiosis
formation of four non-identical cells from one cell.
stage 1 of meiosis
- cell makes copies of its chromosomes, so it has double the amoutn of genetic info
stage 2 meisosis
cell divides into 2 cells, each with half the number of chromosomes, giving 46 chromosomes
stage 3 meiosis
each cell divdes into 2 again to produce 4 cells each with 23
