5.1 and 5.2 - Mendelian Genetics

Question 1

Gregor Mendel

Answer 1

Austrian Monk
“Father” of genetics
Explored patterns of inheritance by crossbreeding thousands of pea plants
Carefully recorded all results of his experiment

Question 2

Humble pea plant

Answer 2

Gregor Mendel chose pea plants for his experiments
Easy to grow and reproduce quickly
Have distinct, observable traits

Question 3

True-breeding plants

Answer 3

consistently produce offspring with the same trait
Mendel crossed true-breeding plants with different traits

Question 4

Cross

Answer 4

The mating of two organisms

Question 5

Parental generation (P)

Answer 5

the original pair of plants being crossed

Question 6

Filial

Answer 6

Relating to offspring

Question 7

F1 generation

Answer 7

first generation of offspring from P cross

Mendel observed uniform traits in F1 generation
Introduced concept of dominant and recessive traits

Question 8

F2 generation

Answer 8

offspring from F1 self-pollination
Mendel observed trait ratios in F2 (e.g., 3:1 for dominant:recessive)

Question 9

what concept did F2 generation introduce

Answer 9

alleles: alternative forms of a gene

Question 10

Genes

Answer 10

codes for a particular trait

Question 11

Alleles

Answer 11

Variation of a trait

Question 12

Phenotype

Answer 12

physical appearance of the trait

Question 13

Genotype

Answer 13

mixture of alleles an organism possesses

Question 14

Homozygous

Answer 14

An organism that has two copies of the same allele

Question 15

Dominant homozygous

Answer 15

AA

Question 16

Recessive homozygous

Answer 16

aa

Question 17

Heterozygous

Answer 17

An organism that has two different copies of the allele
Aa

Question 18

Where do alleles come from

Answer 18

You inherit your alleles and traits from your parents.
Each allele is found in a chromosome. You inherit two copies: one from your mother and one from your father.

Question 19

Meiosis and cell division

Answer 19

During Meiosis I, the homologous chromosomes are divided evenly.
Each allele gets segregated into a different cell.
This is the Law of segregation, organisms only donate one copy of each gene, because of the separation during meiosis

Question 20

Variations: Snapdragons

Answer 20

Snapdragons generally appear red or white
It would be expected that we would see either red or white snapdragons, but no pink snapdragons

Question 21

Codominance

Answer 21

Incomplete dominance is a mixture of two traits.
Codominance is the appearance of both.

Question 22

Blood types

Answer 22

Human blood is both a codominant and dominant trait
There are four possible blood types (excluding +/-):
A, B, AB, O
There are three possible alleles:
IA, IB, i
Both IA and IB are dominant over i. IA and IB are codominant.
They each code for a protein on the surface of a blood cell.
If your blood already has this protein, you can accept blood that has it.
If you do not have this protein, you cannot accept blood with it

Question 23

Polygenic inheritance

Answer 23

Most traits are not off/on, but instead show continuous variation. There is a range of traits resulting from the activity of many genes.
A polygenic trait is a trait that is controlled by more than one gene.