biology 4

• each organism has two alleles per gene • during reproduction alleles separate • each parent gives one allele to the offspring

• different traits are inherited independently from each other • one trait does not affect another

• of two different allies are present • the dominant allele is expressed • the recessive allele is masked

different versions of a gene

genetic makeup (AA, Aa, aa)

physical expression of a trait (what you see)

location of a gene on a chromosome

gene = eye color alleles = brown, blue green phenotype = brown eyes

• use capital letters (A) • dominant traits show if at least 1 dominant alele is present

• use lowercase letters (a) • recessive traits only show if both alleles are recessive

AA = homozygous dominant Aa = heterozygous aa = homozygous recessive

• looks at one trait • typical ex: Aa times Aa • genotype ratio: 1 AA: 2Aa,:1aa • phenotype ratio: 3 dominant : 1 recessive

• looks at two traits the the same time • ex: seed color times pod color • ratio is usually 9:3:3:1

when traits do not follow Mendel’s simple dominant–recessive rules.

both alleles are fully expressed ex: red and white cow hair, human blood type AB

• neither allele is fully dominant • results in a blended phenotype • ex; red flower + white flower = pink flower • RR= red • rr = white • Rr = pink

• trait is controlled by more than one gene • often influenced by environment • height, eye color, skin color

• more than two possible alleles exist for a gene • each person still only has two alleles total • ex: blood type has A, B, O alleles

• carbohydrates • lipids • proteins • nucleic acids

• build bigger molecules • require energy • building proteins from amino acids

• break molecules down • release energy • breaking glucose down for energy

• absorb heat

• release heat

• primary source of energy • easily converted into glucose • used in glycolysis, respiration and photosynthesis • made of carbon, hydrogen, oxygen usually in a CH2O ratio