Chapter 10 Honors Biology Notes
NAME_________________________________
Mendel and Meiosis
10.1
________________ – the passing on of characteristics from parents to offspring
These characteristics are called ______ ___________
Gregor ___ ________, an Austrian monk did experiments on ____________________
___ _____________________ – the study of heredity
He did his experiments on _ _______ plants because they reproduce __ ______ (male and
female sex cells are called ___ _________________)
The male gamete in a plant is the ____ ____________ grain
Fertilization
___ _________________________ – male gamete unites with female and results in a
____________________ cell called a ____ _____________
Pea plants normally reproduce by ___ ___________________________, meaning male and
female gametes come from the __ __________ plant
If they are from __ ________________ plants, it’s called __ ___________-pollination
He studied one trait at a time
He used __ ___________ breeds – plants that have the __ ________ trait for a long time
Monohybrid crosses
Mendel took true breed __ _______ plants and true breed __ _________ plants and __
___________ them (united male and female gametes)
The offspring are known as ___ _______________
____ ___________________ crosses – mono = “____”, hybrid= _ ____ of one trait
1st generation
_ __________ plant x __ ____________ plant
He planted the seeds from this cross
All offspring were __ _____________
2nd generation
He took the 1st generation plants (all _ ________) and they ___ _________
He found that _______ were tall, ________ were short
__ _________ ratio of tall to short
Generations
Parent generation = _________
1st offspring/generation = __________(F = filial, son or daughter)
2nd offspring/generation = __________
Phenotypes and Genotypes
2 organisms can look alike, but have different underlying _______________ combinations
_________________________ – the way an organism ___________ and behaves
________________________ is tall if alleles are _______ or ________
_________________________ – the _______________ combination an organism contains
For __________ plants, genotype could be ____ or ______
For __________ plants, genotype is ________
____________________ – if 2 alleles for a trait are the ___________ (___ or ____)
____________________ – if 2 alleles for a trait are __________________ (Tt)
Dihybrid Crosses
_____________________ crosses – cross ____ traits (tall and yellow)
Mendel crossed round yellow seeds with wrinkled green seeds. Which are dominant/recessive?
For the F1 generation, what did he find?
All _____________ and ________________
For the F2 generation, the F1 self-pollinated and he found
9 ___________ ________________
3 _____________ __________________
3 _________________ ________________
1 ______________ _________________
Law of independent assortment
Genes for __________________ traits are inherited _______________________ of one another
When __________ produces gametes, the alleles R and r will _______________ from each
other, as well as Y and y. they can then _______________ in ______ different ways.
The rule of unit factor
Mendel said there are 2 factors controlling each trait
The factors are __________, located on ___________________________
Genes have _________________ forms called __________________
Example: 2 alleles for height (_________ and _____________)
The 2 alleles are located on different copies of a _______________________ (one from
_______, one from ______________)
Rule of Dominance
The _____________ trait will mask the ___________________
Example: _______ plants are dominant to short, so plants that have one ______________ for
tallness and one for shortness were _______ (Tt = tall)
We use an _________________ letter for dominant and a _______________ letter for recessive.
The dominant trait is always listed ____________
Example: tallness alleles are T for tall and t for short
The law of segregation
Every individual has ___ alleles of each gene and when _________________ are produced, each
gamete receives ________ of these alleles.
During ____________________, these gametes __________________ pair to produce 4
combinations of alleles
Punnett Squares
Reginald _______________ (1905) an English biologist, devised a way of predicting the outcome
of crosses
Called it a Punnett ______________
It takes into account the fact that __________________ occurs _____________________
If you know the ____________________ of the parents, you can use a Punnett square to
__________ the possible genotypes of their __________________.
Example of a monohybrid cross:
Example of a dihybrid cross: