Bio Chap. 12 Patterns Of Inheritance

Front 1

Who planted pea plants and observed their physical traits?

Back 1

Gregor Mendel

Front 2

Gene
Allele

Back 2

Gene = genetic coding for a specific trait
Allele = variation of that trait

Front 3

What terms did Mendel use for genes and alleles?

Back 3

Genes = characters
Alleles = traits

Front 4

In Mendel's experiments, what was the gene and what was the allele?

Back 4

Gene = flower color
Allele = purple or white

For each gene there was 2 alleles

Front 5

Genotype vs. phenotype

Back 5

Genotype = genetic make up
Phenotype = physical (appearance) and physiological (functioning) characteristics; determined by the genotype

Front 6

Carpel
What are they?
Which are they?

Back 6

Female structures of a flower
1) Stigma = a receptive surface for pollen
2) Style = column through which the pollen travels to the ovary
3) Ovary = when fertilizes is the fruit
4) Ovule = egg, when fertilizes is the seed

Front 7

Stamen
What are they?
Which are they?

Back 7

Male structures of a flower
1) Anther = pollen bearing part
2) Filament = arm that supports the anther

Front 8

What is a parental generation called, and what is a descendant generation called?

Back 8

Parental = P
Descendant = F1, F2, F3, etc... (filial = son)

Front 9

Mendel's initial experiment and results

Back 9

Experiment:
P generation purple flowers pollinated with the pollen of the white flowers

Results:
Entire F1 generation grew purple flowers

Front 10

Selfing

Back 10

Pollinating flowers with their own pollen

Front 11

Mendel's second experiment and results

Back 11

Experiment:
He selfed the F1 generation

Results:
3:1 purple to white

Front 12

What did Mendel conclude from his second experiment?
4

Back 12

1) The purple flowers had the white trait, but it was hidden by the purple trait
2) There are recessive and dominant traits
3) Organisms inherit 2 copies of a gene, 1 from each parent
4) dominant and recessive are variants of the same gene

Front 13

Monohybrid cross
When did Mendel do this?

Back 13

When looking at 1 gene

Conducted for the Law of Segregation

Front 14

Law of Segregation

Back 14

• Mendel's version of homologous pairs in meiosis
• The 2 alleles for a gene separate during meiosis and are rejoined at random at fertilization
• 1 allele is from each parent

Front 15

What are dominant and recessive alleles are represented by?

Back 15

Dominant = capital letter; ex. G for green pea pod color

Recessive = the same letter, lowercase; ex. g for yellow pea pod color

Front 16

Homozygous
Homozygous dominant
Homozygous recessive
Heterozygous

Back 16

Homozygous = 2 identical alleles
Homozygous dominant = 2 dominant alleles; ex. GG
Homozygous recessive = 2 recessive alleles; ex. gg
Heterozygous = 1 dominant, 1 dominant allele; ex. Gg

Front 17

Test cross
Why it's used (2)
What is done (1)
Possible results (2)

Back 17

• Used when an individual is expressing a dominant phenotype, but the genotype is unknown
• determines if individual is homozygous dominant or heterozygous
• mate the individual with a homozygous recessive

Results:
1) homozygous dominant = all offspring will be heterozygous and exhibit the dominant trait
2) heterozygous = 1/2 the offspring will be heterozygous and exhibit the dominant trait, and 1/2 will be homozygous recessive and exhibit the recessive trait

Front 18

Dihybrid cross
When did Mendel do this?

Back 18

When looking at 2 genes

Conducted for the Law of Independent Assortment

Front 19

Law of Independent Assortment

Back 19

1) Since chromosomes randomly align during metaphase I on the metaphase plate, they segregate independently of one another during anaphase
2) alleles that are paired in one generation do not necessarily get inherited as a pair

Front 20

When does the Law of Independent Assortment not apply?

Back 20

When genes are closely located on the same chromosome because these genes travel together during anaphase of meiosis

Front 21

What phenotype ratio did Mendel expect to see in his dihybrid cross, and what did he actually see?

Back 21

He expected 3:1 → would imply that pairs of alleles get passed on together

Actually saw 9:3:3:1 → illustrates the Law of Independent Assortment

Front 22

Incomplete dominance

Back 22

• heterozygote appears a blend of the 2 alleles
• this is not due to blending inheritance, but rather due to failure of dominance

Front 23

Co-dominance
Example

Back 23

• No single allele is dominant, so the heterozygote shows some aspect of both alleles
• Ex. human blood type

Front 24

Polygenic inheritance
2 types

Back 24

1) Polygenic = many genes controlling a trait
2) Multifactorial = many factors controlling a trait, ex. environment