D3.2 Inheritance

Question 1

What’s is the punnet square used for?

Answer 1

Predict offspring, genotype

Question 2

Genetic inheritance

Answer 2

Genetic info passed onto offspring

Question 3

Benefits of using pea plants in experimentation for inheritance

Answer 3

• Annual plant
• 2 clear versions of each trait
• Self pollinating plants — ensures they are homozygous (pure breeding)

Question 4

What is a gamete

Answer 4

Reproductive cell of an animal or plant

Question 5

Pollen of pea plants contain…

Answer 5

Male gametes
Female gametes — ovules in the carpel

Question 6

What are the 3 generations?

Answer 6

Original parents in a genetic cross — P generation
Offspring of P generation — F1 generation
Offspring of 2 individuals from the F1 generation — F2 generation

Question 7

How does breeding new varieties of crops & ornamental plants work?

Answer 7

Genetic crosses

Question 8

Genes

Answer 8

Sections of the DNA that code for a specific protein & determine a trait

Question 9

Alleles

Answer 9

Alternative forms of a gene (produced by mutations to a gene)

Question 10

Genotypes

Answer 10

Combination of alleles inherited by an organism

Question 11

Homozygous

Answer 11

Individuals have 2 identical copies of an allele for a gene

Question 12

Heterozygous

Answer 12

Individuals have 2 different copies of an allele for a gene

Question 13

Phenotypes

Answer 13

Observable traits of an organism determined by the genotype interacting with the environment

Question 14

Traits that are determined by genotypes only

Answer 14

Blood type
Genetic disease
Eye colour

Question 15

Traits determined by genotype interacting with the environment

Answer 15

Height
Athletic performance

Question 16

Traits determined by the environment only

Answer 16

Language spoken
Accent

Question 17

Alleles can either be ________ or _________

Answer 17

Dominant
Recessive

Question 18

Bb

Answer 18

Dominant

Question 19

bb

Answer 19

Recessive

Question 20

BB

Answer 20

Dominant

Question 21

Homozygous dominant

Answer 21

2 copies of the dominant allele

Question 22

Homozygous recessive

Answer 22

2 copies of the recessive allele or heterozygous (2 different alleles)

Question 23

Phenotypic plasticity

Answer 23

Capacity to develop traits suited to the environment experienced by a organism (by varying patterns of gene expression)

Question 24

What is Phenylketonuria? (PKU)

Answer 24

Human disease due to a recessive allele (mutation)
—> Homozygous recessive — unable to make enzyme to convert phenylalanine to tyrosine

Question 25

High concentrations of phenylalanine build up in the brain causes…

Answer 25

Delayed development Behavioural, emotional & social problems

Question 26

Gene pools

Answer 26

All the different genes & alleles present within an interbreeding population of a species

Question 27

When do multiple alleles occur?

Answer 27

When there are more than 2 alleles for a gene

Question 28

What are the 3 common alleles for human blood types?

Answer 28

I^A I^B i

Question 29

What is the genotype for phenotype O

Answer 29

ii

Question 30

What is the genotype for phenotype A

Answer 30

I^A I^A or I ^A i

Question 31

What is the genotype for phenotype B

Answer 31

I^B I^B or I^B i

Question 32

What is the genotype for phenotype AB

Answer 32

I^A I^B

Question 33

Complete dominance

Answer 33

1 allele is dominant & masks the presence of the other allele

Question 34

Incomplete dominance

Answer 34

Heterozygotes have an immediate phenotype to homozygous individuals (neither allele is dominant)

Question 35

Example of incomplete dominance

Answer 35

Four o’clock flower - 3 phenotypes (red, pink, white) - When flower is heterozygous for flower colour — intermediate between red & white phenotypes

Question 36

Co-dominance

Answer 36

Both traits are visible in phenotype —> occurs when heterozygotes have a dual phenotype

Question 37

X & Y chromosomes determine what?

Answer 37

The sex

Question 38

What are the differences found between X & Y chromosomes

Answer 38

X — longer, more genes, no SRY gene Y — shorter, contain SRY gene (develop male characteristics)

Question 39

XX

Answer 39

Female

Question 40

XY

Answer 40

Male

Question 41

Sex linked traits

Answer 41

Allele is presented on 1 sex chromosome (usually X)

Question 42

Haemophilia

Answer 42

Disease where gene is on the X chromosome but not the Y —> Can’t clot blood

Question 43

Pedigree charts

Answer 43

Diagram that shows the occurrence & appearance of phenotypes of a particular gene or organism & its ancestors from 1 ancestor from 1 generation to the next

Question 44

Polygenic inheritance

Answer 44

Single characteristic controlled by multiple genes

Question 45

Melanin

Answer 45

Brown protein pigment

Question 46

What does inheritance of skin colour in humans depend on?

Answer 46

Amount & type of melanin present in skin

Question 47

Discrete variation

Answer 47

Results from 1 gene being responsible for a trait

Question 48

Continuous variation

Answer 48

Multiple genes determine the phenotype

Question 49

When representing spread of data for a continuous variable, use what?

Answer 49

Box & whisker plot

Question 50

Outlier

Answer 50

Data point that differs significantly from other data points