inheritance SWA

Sequence of nucleotides on Dna that code for particular protein

site on a chromosome occupied by a gene

a gene always expressed when present

gene only expressed in a homozygous pair

both alleles contribute to the phenotype

characteristics of an organism

alleles in organism

alleles are the same (HH / hh)

alleles are different (Hh)

first gen in genetic cross, starts with pair of homozygotes

Second gen produced by crossing F1 gen

chromosome that isn’t a sex chromosome (1-22 in humans)

X and Y, pair 23 in humans

both alleles expressed in phenotype

blend of both alleles can be seen in phenotype

pea plants
easy to grow
short life cycle
easily observable characteristics

controlled by single genes
on different chromosomes

single gene inheritance

law of segregation
characteristics of organism are determined by factors (genes) that are in pairs
only one member of pair of factors (genes) can be represented in a gamete

genes located on same chromosome, inherited together

genes located on different chromosomes

2 genes inherited

indp asst of chromosomes happens in meiosis
unlinked genes can combine to form 4 kinds of gametes

dominant yellow / round
recessive green / wrinkled traits

medelian ratio- 9:3:3:1

if expected ratio isnt found in offspring

stats test to determine if numbers and phenotypes of offspring produced is close to mendelian ratio

statement, either eg.
no difference between observed and expected results of cross
either reject or accept

number of outcomes -1
eg if 4 outcomes then degrees of freedom=3

the law of independent assortment

sex linked genes are on the sex chromosomes

superscript on chromosome (above it)

disease caused by recessive allele for factor 8 that doesnt code for normal blood clotting factor

progressive muscle disease caused by sex linked recessive allele that doesnt code correctly for the protein dystrophin

spontaneous random change in a gene

in organisms that have short life cycles or frequent cell division

during cross over in prophase 1 and non-disjunction in anaphase 1&2

mutation affect protein synthesis- so change phenotype
leads to variation in species- cause evolution by natural selection

protooncogenes can mutate to become oncogenes causing uncontrolled cell division to form cancer