SSA Review 12 Heredity Genetics ity the passing

SSA Review 12 – Heredity & Genetics

ity – the passing of traits from parents to offs – physical characteristics of an organism is why offspring look like their parents ake a look at some examples.

r color *Eye color *Widow’s Peak *Toe length *Hitchhiker Th

ts are found in genes ed from parent to ring) within the cell’s us

es are part of (Deoxyribonucleic acid) - material that ns all the different ble Helix – the structure of DNA resembles a ed ladder

A is strung together ng strands called mosomes re are 23 pairs of mosomes in each A is the blueprints for building cells, tissue, ns, and the organism

Cell Division

Mitosis *The process where cells (parent cells) reproduce duplicate cells (daughter cells) Muscle cells produce new muscle cells, bone cells produce new bone cells, etc.

Meiosis process of ducing sex cells

MITOSIS MEIOSIS

How are chromosomes, genes, and inheritance related? 46 chromosomes The human body has ____ in each cell *23 pairs A baby gets 23 chromosomes from their ________ father and 23 from their mother *Total - 46

Why don’t offspring always look exactly like their parents then?

es and Alleles control the inheritance of s are the different forms of (traits) from each parent

es and Alleles - Plant Height s: Tall Plant Short plant

es and Alleles inant allele- trait that s shows up in an ism when its present lant (T)

es and Alleles ssive allele – the trait is n when the dominant s present r case letter) plant (t)

Phenotype and Genotype – the physical appearance, traits, of an organism rown Hair, Black hair ight handed, left handed all, short

Phenotype and Genotype – the genetic makeup, or mbination of alleles, of an organism ir color: own Hair (B), Black Hair (b) own hair – BB, Bb ck hair - bb

Phenotype and Genotype it – Handedness enotype – Right handed (R), handed (r) notype – RR, Rr, rr

Alleles for Rabbit Ears: Straight - dominant (S), Floppy - recessive (s) Phenotypes Genotypes SS Ss ss

Alleles for Guinea pig fur color: Brown – dominant (B), White – recessive (b) Phenotypes Genotypes BB Bb bb

Alleles for Skin Complexion: Clear – dominant (C), Freckled – recessive (c) Phenotypes Genotypes CC Cc cc

Homozygous & Heterozygous Alleles mozygous – organism with 2 identica eles for a trait (BB, DD, rr) urebred terozygous – organism with 2 differe eles for a trait (Bb, Dd, Rr) ybrid

Alleles for Rabbit Ears: Straight-dominant (S), Floppy-recessive (s) Phenotypes Genotypes Homozygous or Heterozygous SS Homozygous Ss Heterozygous ss Homozygous

Alleles for Guinea pig fur color: Brown – dominant (B), White – recessive (b) Phenotypes Genotypes Homozygous or Heterozygous BB Homozygous Bb Heterozygous bb

Alleles for Hair type: Curly – dominant (C), Straight – recessive (c) Phenotypes Genotypes Homozygous or Heterozygous CC Homozygous Cc Heterozygous cc

How are chromosomes, genes, and inheritance related? The alleles from the female and the alleles from the male combine together in one of ___ 4 possible combinations Punnett Square shows what these A ________ possible combinations can be

Punnett Square A chart that shows all the possible ways alleles can combine in a genetic cross.

A rabbit with straight ears (Ss) breeds with a rabbit with floppy ears (ss). What are the probable outcomes for the offspring? S s s Ss ss

Combinations: Ss = 2 ss = 2 Possible = 4 Straight ears (S) = 2 of 4 (50%) Floppy Ears (ss) = 2 of 4 (50%) S s s Ss ss

Example – Clear skin (C) is dominant to freckled skin (c). What is the probability that an offspring will have freckles if both of their parents have clear skin (Cc)? *Set up a Punnett square to answer this. Answer = 25%

Example – Brown hair (B) is dominant to blonde hair (b). What is the probability that an offspring will have blonde hair if one parent has brown hair (BB) and one parent has blonde hair (bb)? Answer = 0%

Example – The male sex trait (Y) is dominant to the female sex trait (x). The male sex trait is heterozygous (Yx) and the female sex trait is homozygous (xx). What is the probability a child is born male or female?

F a t h e r x x Mother Y Yx Yx y = male x = female x xx xx 2 of 4 chances the baby will There are ___ be male and ___ 2 of 4 chances the baby will be female (50 % / 50 %)