Mendel and Inheritance of Traits Notes

traits offspring genes Heredity: passing of _______ from parent to ___________ ● Trait: ________________ that an organism can pass to its offspring through _______. traits offspring characteristic genes

2) Genetics: the study of how traits are ___________ through the actions of alleles inherited

3) Gregor Mendel: the _______ of modern genetics Used ____ _______ to study how traits are passed from parents to offspring father pea plants

First Experiment: Crossed purebred ____ plants with purebred _______ plants tall short This plant is purebred tall. This plant is purebred short.

Results: _____- generation were ___ ____ plants (no short) first all tall

self Second Experiment: first-generation ____ plants _____- pollinate tall self

second tall short three tall one short 1 2 3 1 Results: _________- generation plants were _____ and _______ There were _______ _____ plants for every _____ _______ plant (a 3:1 ratio). second tall short three tall one short 1 2 3 1

predict traits dominant Determined we can _________ _______ of offspring based on the parents’ traits Figured out ___________ and recessive alleles predict traits dominant dominant recessive

chromosome 4) Gene: section of DNA on a ________________ that directs the making of a specific ________ . chromosome protein Each gene codes for 1 protein

An organism’s genes are inherited from its _________. parents

5) Allele: the different forms a ______ may have for a trait gene

Alleles can be ___________ or ___________ dominant recessive Dominant alleles Recessive alleles

Dominant: ________ up or masks the ___________ Dominant: ________ up or masks the ___________. We only see the dominant trait. Use _________ letters to represent dominant traits. Ex: T or P covers recessive capital

*Both parents recessive alleles are hidden by the dominant. Recessive: ________ by the dominant allele. We only see if ______ ________ for the trait are ___________. hidden both alleles recessive *Both parents recessive alleles are hidden by the dominant. Use _______ case letters to represent recessive traits. Ex: t or p lower CF=cystic fibrosis

6) Genotype: the genetic __________ of an organism (its alleles) It is written with letters such as ___ or ___ or ___ make-up TT Tt tt

tt TT Homozygous: having two ________ that are the _______ for a trait Example: ___ or ___ alleles same TT tt

Tt Heterozygous: having two __________ alleles for a trait different Example: ___ different Tt

Dominant Genes Recessive Genes Genotype: AA or Aa Genotype: aa

7) Phenotype: the __________ expression of a particular ___________ It is what a ______ looks like Example: blue eyes, _____ _________, tall plants, etc. physical genotype trait red flowers

Phenotype: Brown/Black Phenotype: White/Yellow Dominant Genes Recessive Genes Genotype: AA or Aa Genotype: aa Phenotype: Brown/Black Phenotype: White/Yellow

shows alleles combine 8) Punnett Squares: A Punnett square ________ how the parents’ ________ might ___________ in offspring. shows alleles combine

top one parent’s alleles side second alleles The ____ of the square shows _____ __________ ________ for the trait. The ______ of the square shows the _________ parent’s ________ for the trait. top one parent’s alleles side second alleles

box alleles combine offspring Each _____ shows one way the ________ might ___________ in potential ___________. box alleles combine offspring

T T T t t t T T T t t t Let’s try some Punnett squares! Ex.1: A heterozygous tall plant (Tt) is crossed with another heterozygous tall plant (Tt). T T T t t t Next we fill in the Punnett square. T T T tall tall What would the offspring look like? t t t tall short

T T T T T T T T T t t t Now it’s your turn! Ex.2: A homozygous tall plant (TT) is crossed with a heterozygous tall plant (Tt). T T T T T T Now fill in the Punnett square. T T T tall tall What would the offspring look like? t t t tall tall