Pattens Of Inheritance

Question 1

Interspecific variation.

Answer 1

Between members of different species e.g. humans and cats.

Question 2

Intraspecific varition.

Answer 2

Between members of the same species e.g. different types of dogs.

Question 3

Genotype

Answer 3

The genetic make up of an organism, which alleles are present.

Question 4

Phenotype

Answer 4

The physical characteristics of an organism (not always visible, might be psychological).

Question 5

What are the three things meiosis produces genetic variation from?

Answer 5

1- Alleles shuffling during crossing over (prophase 1).
2- Independent assortment of chromosomes (metaphase/anaphase 1).
3 - Independent assortment of chromatids (metaphase/anaphase 2).

Question 6

Homozygous.

Answer 6

2 identical alleles for a gene can be dominant or recessive.

Question 7

Heterozygous.

Answer 7

Organism has 2 different alleles for a gene.

Question 8

Monomorphic genes.

Answer 8

Genes that only have 1 possible allele.
Most genes are monomorphic for a particular population as they are necessary for many of the proteins we need to make, e.g. respiratory enzymes coded for by the same allele.

Question 9

Polymorphic genes.

Answer 9

Genes that have more than 1 possible allele.
The greater the proportion of polymorphic gene loci, the greater the genetic variation within the population.

Question 10

How do you work out the proportion of polymorphic genes?

Answer 10

Number of polymorphic genes in a population/ number (total) of genes in a population.

Question 11

Features of continuous variation.

Answer 11

• No distinct categories -> individuals vary within a range e.g. height, weight, fur length.
• polygenetic (controlled by a large number of genes) -> affects phenotype.
• environment plays a role.

Question 12

Features of discontinuous variation.

Answer 12

• distinct categories -> no intermediates. E.g. blood groups.
• Monogenetic (controlled by 1 gene)
• Environment has little/no effect.