Chapter 17 - Inherited Change

Question 1

Genetically, where do the similarities and differences lie between organisms of the same species?

Answer 1

They will have the same genes usually at the same loci, however they will have different alleles which are usually passed down by parents

Question 2

What is the genotype?

Answer 2

The genetics or the genetic constitution of an organism

Question 3

What is the phenotype?

Answer 3

The expression of the characterstics from the proteins produced by the genotype, as well as environmental factors

Question 4

What is an allele?

Answer 4

Different versions of the same gene, resulting in a different phenotype

Question 5

What are the three forms of an allele?

Answer 5

Dominant, recessive and codominant

Question 6

What is the difference between a homozygous or heterozygous allele?

Answer 6

At the same locus on each of your chromosomes, you may have the same or different alleles. If they are the same on both chromosomes they are homozygous, and if they are different they are heterozygous

Question 7

What is monohybrid inheritance?

Answer 7

The most simple type of inherited characteristic, where only one gene is being inherited, and there are only dominant and recessive alleles leading to 4 distinct probabilities of a phenotype being expressed, such as brown eyes being dominant to blue

Question 8

What is codominance?

Answer 8

Codominance is where 2 different alleles can both be expressed in the phenotype at once, such as red and white petals being codominant, therefore in a heterozygous plant there would be pink petals

Question 9

What is dihybrid inheritance?

Answer 9

Dihybrid inheritance is where two different genes are being passed on at once, resulting in a genetic cross of 16 different possibilites

Question 10

What is sex linkage?

Answer 10

Sex linkage is where an allele is bound to the X chromosome, meaning it can is never present, whether dominant or recessive, on the y chromosome in men. This means that even if their x chromosome has the recessive allele, the y chromosome does not have an allele to oppose the expression in the phenotype provided by the recessive allele, so genetic diseases are more easily expressed in men if they are sex linked

Question 11

What is autosomal linkage?

Answer 11

Autosomal linkage is also where two chromosomes are linked, however in a different way, where they instead have the dominant alleles of two different genes linked and the recessive alleles of two different genes linked

Question 12

What is epistasis?

Answer 12

Epistasis is the idea that one gene or allele affects the expression of another, or whether it is expressed at all