Question

Question 1

The two alternatives for a trait are red and white and red is dominant. However, white is the most common trait. What is the genotype of a homozygous dominant individual?

	a) RR
	b) rr
	c) WW
	d) ww
	e) red

Question 2

Where the two alternatives for a trait are broad and narrow, and broad is dominant, the phenotype of a homozygous dominant individual would be expressed as

	a) BB
	b) nn
	c) Bn
	d) NN
	e) broad

Question 3

A genetic disorder caused by a dominant allele is

	a) sickle-cell anemia
	b) PKU
	c) Tay-Sachs disease
	d) hemophilia
	e) Huntington’s disease

Question 4

One gene can have multiple effects on an organism.

	a) True
	b) False

Question 5

A trait caused by a recessive autosomal allele will result in a pedigree that shows affected individuals having at least one affected parent.

	a) True
	b) False

Answer 1

Question 1-

All copies of a gene are not identical and alternative forms of a gene is called alleles that lead to the alternative or different form of one trait. Alleles are helpful in identification of the two members of a gene pair, which produce opposite contrasting phenotypes, e.g., b is an allele of B and vice versa. When the two alleles of a gene are identical, the individual is homozygous for that trail, and on the other hand, if there are two different alleles, the individual is heterozygous. A homozygous pair can be either dominant (AA, BB) or recessive (aa, bb). Heterozygous pairs are made up of one dominant and one recessive allele (Aa, Bb). In heterozygous individuals, only one allele, the dominant one, is able to express itself, while the other allele, the recessive, is hidden but still present. The dominant genes are denoted by upper case letters and recessive genes are denoted by lower case letters. The word genotype was created to identify genes of an individual and phenotype for the external appearance of the trait and genes.

Answer- a) RR

Question 2-

An individual's phenotype consists of the traits we can observe. A phenotype is the composite of an organism's observable characteristics or traits, such as its morphology, development, biochemical or physiological properties, behavior, and products of behavior.
Pheynotypes are traits that can include things like:
your height and weight, skin color, cholesterol levels, sex (male/female), the amount of protein X produced in your blood cells, the particular composition of fatty acids used to make your cell membranes, the number of mitochondria you have, any diseases you have (mental or physiological), your personality, your intelligence, your age etc.

Since here the dominant is mentioned Broad, the phenotype of a homozygous dominant individual would be expressed as broad.

Answer- e) broad.

Question 3-

If the dominant allele is present, then the person will express the disease. A child only has to inherit one dominant allele to have the disease.

Huntington’s disease is an example of an autosomal dominant disorder.The disease causes the brain’s cells to break down, leading to muscle spasms and personality changes. Unlike most other genetic disorders, the symptoms usually do not become apparent until middle age. If one parent has Huntington’s disease, the chance of passing it on to the children is a 50 percent chance of the disorder being passed on to the children.

Answer- e) Huntington’s disease.

Question - 4

Single gene may have multiple effects on the phenotype of organism.
This is due to: the expression of a single gene may affect cell function in multiple ways, A gene may be expressed in different cell types in one organism, A gene may be expressed at different stages of development
example: many symptoms of sickle cell are caused by one gene.

Answer- True

Question- 5

Answer- False