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Question 1

Define genotype

Answer 1

The genetic constitution of an organism

Question 2

Define phenotype

Answer 2

The expression of the genotype and its interaction with the environment

Question 3

What are alleles and how do they arise

Answer 3

Alleles are variations of a particular gene with the same locus and they arise by mutation (change in DNA base sequence)

Question 4

What are alleles and how do they arise

Answer 4

Alleles are variations of a particular gene with the same locus and they arise by mutation (change in DNA base sequence)

Question 5

How many alleles of a gene can be found in diploid organisms?

Answer 5

2 as diploid organisms have 2 sets of chromosmes but there may be more than 2 alleles of a single gene in a population

Question 6

Describe the different types of alleles

Answer 6

Dominant allele ALways expressed and shown in phentoype
Recessive allele- Only expressed when 2 copies are present (homozygous recessive) not when heterozygous
Co dominant alleles- Both alleles expressed/contribute to phenotype

Question 7

Describe the different types of alleles

Answer 7

Dominant allele ALways expressed and shown in phentoype
Recessive allele- Only expressed when 2 copies are present (homozygous recessive) not when heterozygous
Co dominant alleles- Both alleles expressed/contribute to phenotype

Question 8

Define homozygous and heterozygous

Answer 8

Homozygous- Alleles at specific locus on each homologous chromosome are the same
Heterorzygous- Alleles at a specific locus on each homologous chromosme are different

Question 9

Define homozygous and heterozygous

Answer 9

Homozygous- Alleles at specific locus on each homologous chromosome are the same
Heterorzygous- Alleles at a specific locus on each homologous chromosme are different

Question 10

What do monohybrid and dihybrid crosses show?

Answer 10

Monohybrid cross- Inheritance of one phenotypic characteristic coded for by a single gene
Dihybrid cross- Inheritance of two phenotypic characteristics coded for by 2 different genes

Question 11

What do monohybrid and dihybrid crosses show?

Answer 11

Monohybrid cross- Inheritance of one phenotypic characteristic coded for by a single gene
Dihybrid cross- Inheritance of two phenotypic characteristics coded for by 2 different genes

Question 12

What is a sex linked gene

Answer 12

Gene with a locus on a sex chromosome
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Question 13

What is a sex linked gene

Answer 13

Gene with a locus on a sex chromosome
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Question 14

Explain why males are more likely to express a recessive x linked allele

Answer 14

This is because, men have XY chromosmes that have 1 allele and this recessive allele is always expressed. WOmen have XX chromosomes and so they can be carriers, females have to be homozygous in order to express the gene and this is less likely

Question 15

Explain why males are more likely to express a recessive x linked allele

Answer 15

This is because, men have XY chromosmes that have 1 allele and this recessive allele is always expressed. WOmen have XX chromosomes and so they can be carriers, females have to be homozygous in order to express the gene and this is less likely

Question 16

Explain how autosomal linkage affects inheritance of alleles

Answer 16

-Two genes located on the same autosome (non sex chromosome)
-Alleles on the same chromosome are inherited together as they stay togehter during independent segregation of homologous chromosomes during meiosis
-But crossing over between homologous chromosomes can create new combinations of alleles
If the genes are closer together on a autosome, they are less likely to be split by crossing over