Chapter 7- Genotypes and Phenotypes

Question 1

What is a Genotype?

Answer 1

both the double set of
genetic instructions present in a
diploid organism and the genetic
make-up of an organism at one
particular gene locus

Question 2

What is a phenotype?

Answer 2

an observable or
measurable characteristic of
an organism that is the product
of genetic and environmental
factors

Question 3

What is hemizygous?

Answer 3

the genotype
with respect to any gene
carried on either the X or the Y
chromosome, which comprises
just a single allele for each gene

Question 4

What a carrier?

Answer 4

an organism that has inherited an allele for a recessive trait but does not display that trait or symptom

Question 5

Define Codominance

Answer 5

when a heterozygous organism expresses both alleles in its phenotype.

Question 6

Define Incomplete dominance

Answer 6

the appearance in a heterozygote of a trait that is intermediate between either of the trait’s homozygous phenotype

Question 7

What is Epigenetics?

Answer 7

The study of changes in organisms caused by modifications of gene expression rather than change in the genetic code itself

Question 8

What are epigenetic factors?

Answer 8

External factors which change the expressions of genes, but not the base DNA sequence

Question 9

What is a methyl group?

Answer 9

A group of one carbon atom bonded to three hydrogen atoms

Question 10

What’s methylation?

Answer 10

The addition of a methyl group to a cytosine base of DNA, usually to repress gene transcription