genetic variation Flashcards
(21 cards)
genotype
genetic makeup of an organism
what is a phenotype
visible characteristic of an organism
what influences a phenotype
genotype and environment
what are the three mutagenic agents which increase chance of mutations
physical agents
chemical agents
biological agents
give an example of a physical agent
x ray
give an example of a biological agent
some viruses
what is a deletion
when part of a chromosome loses its genes
what is a inversion
a selection of a chromosome may break off, turn 180 degrees and join again.
genes are now too far away from their regulatory nucleotide sequences to be properly expressed.
what is a translocation mutation
some chromosome breaks off and joins another
what is duplication
piece of chromosome may be duplicated- overexpression of genes can be harmful
what is non disjunction
chromosomes or chromatids dont separate, leaving one gamete with an extra chromosome.
Down syndrome.
what does aneuploidy mean (key term)
the chromosome number isn’t an exact multiple of the haploid number for that organism
what is the difference between haploid and diploid
haploid (n)- gamete
single set of chromosomes
diploid (2n)- human body cells
two sets of chromosomes
what processes do diploid and haploid use to divide
meiosis- haploid
mitosis- diploid
give example of diploid cell
blood cell
muscle cell
skin cell
(somatic cell)
haploid cell examples
sperm cell
ova
(germline cells)
what is POLIPLOIDY (KEY TERM)
when a organism has more than 2 sets of chromosome
when a diploid gamete is fertilised by a haploid gamete, the zygote will be TRIPLOID. three sets of chromosomes.
cultivated plants are polyploidy and have more than 2 sets
where does genetic variation occur in meiosis
allele shuffling between non sister chromatids- prophase 1
metaphase1/ anaphase 1- independent assortment of chromosomes.
independent assortment of chromatids during metaphase and anaphase 2.
independent assortment of chromosomes, happens in which phase on meiosis
metaphase 1- independent assortment of homologous pairs
anaphase 1- independent assortment, which chromosomes get pulled to which side of the cell
how is gamete fusion geneticallt diverse
any male gamete can combine with any female gamete from an organism of the same species.
how can the environment influence variation
losing a limb
having a scar after something like a surgery
