Module 6.1.2 - Patterns of inheritance and variation

Question 1

What is an allele?

Answer 1

Different versions of same gene

Question 2

What does genotype mean?

Answer 2

Alleles an organism

Question 2

What does phenotype mean?

Answer 2

Characteristics displayed by an organisms

Question 3

What does epistasis?

Answer 3

More than one gene affecting characteristic
e.g. eye colour

Question 4

What are the 2 genetic factors?

Answer 4

• polygenic
• monogenic

Question 5

What is polygenic?

Answer 5

• continuous variation
• controlled by many genes

Question 6

What is monogenic?

Answer 6

• discontinuous variation
• controlled by 1 gene

Question 7

What is etiolation?

Answer 7

Plants grown abnormally long and spindly due to not enough light

Question 8

What is chlorosis?

Answer 8

Plants dont produce enough chlorophyll due to lack of magnesium (prosthetic group)

Question 9

What us interspecific variation?

Answer 9

Variation between species

Question 10

What us intraspecific variation?

Answer 10

Differences between individuals of same species

Question 11

What is continuous variation?

Answer 11

• many genes/alleles
• quantitative
• controlled by both genes and environment
• normal distribution curve

Question 12

What is discontinuous variation?

Answer 12

• limited amount of genes/alleles
• qualitative
• controlled by genes
• not environment
• bar chart

Question 13

What is monogenetic inheritance?

Answer 13

Characteristics controlled by 1 gene

Question 14

What is codominance?

Answer 14

Both alleles are expressed and neither one is recessive

Question 15

Give an example of codominant alleles

Answer 15

Sickle cell anaemia

Question 16

What is dihybrid inheritance?

Answer 16

Inheritance of 2 characteristics controlled by different genes

Question 17

What are the 4 blood groups?

Answer 17

A, B, AB, O

Question 18

What are the allele combinations of each blood group?

Answer 18

A - I^A I^A, I^A I^O
B - I^B I^B, I^B I^O
AB - I^A I^B
O - I^O I^O

Question 18

What are some example of sex linkage?

Answer 18

• hemophilia
• colour blindness
• duchenne muscular dystrophy

Question 19

What is an autosome?

Answer 19

Chromosome that’s not a sex chromosome

Question 20

What does linkage of autosomal chromosomes crossing over during meiosis do?

Answer 20

The closer the genes, the less likely they are to get separated from crossing over

Question 21

What is epistasis?

Answer 21

When 1 gene masks or suppresses the expression of another

Question 21

What does linkage of autosomal chromosomes independent assortment during meiosis do?

Answer 21

Genes on same autosome are said to be ‘linked’ as they stay together during independent assortment

Question 21

What is an example of epistasis?

Answer 21

In humans, if you have the gene for baldness then it doesn't matter if you have the gene for widow's peak as you have no hair

Question 22

What does epistasis dominant mean?

Answer 22

Having a dominant epistasis allele, 1 copy will mask the expression of other gene

Question 23

What is the chi-squared test?

Answer 23

- measures size of difference between observed and expected results helps determine whether differences are significant or not - null hypothesis=no significance

Question 24

What is a species?

Answer 24

Group of organisms that can reproduce to form a fertile offspring

Question 25

What is speciation?

Answer 25

The development of new species when population becomes reproductively isolated and can no longer interbreed, changes in allele frequency lead to change in phenotype

Question 26

What is allopatric speciatio?

Answer 26

- physical barrier occurs and causes geographical isolation, 2 populations now - mutations occur but the new alleles aren't shared between populations as no interbreeding - separates gene pool - natural selection creates variation from the mutations - change in allele frequency - differential reproductive success - barrier is removed - new species are created that can't be bred together, speciation

Question 27

What is sympatric speciation?

Answer 27

- don't have to be geographically isolated to become reproductively isolated - random mutations could lead to reproductive isolation - is rare as difficult for sections or as population reproductively isolated

Question 28

What are the 2 types of speciation?

Answer 28

- allopatric - sympatric

Question 29

What is reproductive isolation?

Answer 29

Changes in alleles and phenotype of 2 populations that prevents them from successfully breeding together

Question 30

What are some examples of reproductive isolation?

Answer 30

Seasonal changes - different flowering/mating seasons Mechanical changes - changes in gentitalia prevent successful mating Behavioural changes - different courtship rituals developed

Question 31

What is artificial selection?

Answer 31

Type of selective breeding

Question 32

What are some problems with artificial selection?

Answer 32

- cause health problems - reduced genetic diversity and gene pool - more susceptible to genetic diseases - alleles are lost - certain traits may be exaggerated