Topic 4b - Inheritance

Question 1

What is Lamarckianism?

Answer 1

changes in condition are passed onto offspring

Question 2

Years Mendel conducted pea experiments?

Answer 2

1856-1863

Question 3

Which traits did Mendel choose to work with?

Answer 3

seed shape
seed colour
flower colour
pod shape
pod colour
flower/seed position
stem length

Question 4

Define progeny…

Answer 4

offspring of mating/breeding

Question 5

Define F1 generation…

Answer 5

First filial generation (cross between 2 pure breeding strains)

Question 6

Define F2 generation…

Answer 6

2nd filial generation (progeny of crosses of F1 progeny)

Question 7

Define dominant…

Answer 7

trait that masks the presence of a recessive trait

Question 8

Define recessive…

Answer 8

a variant expressed only when a dominant trait is absent

Question 9

Define the Law of Segregation…

Answer 9

Individuals carry 2 alleles of each gene controlling inherited traits. Alleles partition themselves when gametes form so that each gamete has only one pair of alleles. eg. Gg -> 1G & 1g = 1 ‘green’ allele in one gamete & 1 ‘yellow’ allele in the other gamete

Question 10

Define genotype…

Answer 10

combination of alleles in an organism

Question 11

Define phenotype…

Answer 11

the physical/observable characteristic

Question 12

What does a punnett square predict?

Answer 12

genotypic & phenotypic frequencies

Question 13

Define pleiotropy…

Answer 13

a single gene controls more than one phenotypic trait

Question 14

Define incomplete dominance…

Answer 14

phenotype of a heterozygous individual is intermediate between that of each homozygote eg. Red snapdragon + white snapdragon = pink snapdragon

Question 15

Incomplete dominance ratio?

Answer 15

1 : 2 : 1

Question 16

An example of co-dominance…

Answer 16

blood type in humans

Question 17

Which blood types are most to least common…?

Answer 17

A & B (most common), then AB, then O

Question 18

4 types of cross…

Answer 18

monohybrid
dihybrid
testcross
backcross

Question 19

In dihybrid crosses, F1 generation shows what? F2 generation?

Answer 19

F1 - all dominant traits

F2 - combination of dominant & recessive traits

Question 20

Typical dihybrid cross F2 ratio…?

Answer 20

9:3:3:1

Question 21

Define the law of independent assortment…

Answer 21

Traits don’t affect each other - alleles of one trait assort into gametes independently of alleles of another gene controlling a different trait

Question 22

Sex-linked traits controlled by…?

Answer 22

sex chromosomes (X or Y)

Question 23

T or F - environment has no effect on phenotype

Answer 23

false - environment can affect genotype & phenotype

eg. alkaline pH = pink flower, acidic pH = blue flower