Understanding Genes and Alleles

Who is known as the father of genetics for his work on pea plants?

• Charles Darwin

• Gregor Mendel

• Albert Einstein

• Louis Pasteur

What is an allele?

• A type of cell

• A form of a gene

• A type of protein

• A type of chromosome

Which of the following describes a dominant gene?

• A gene that is always expressed in the phenotype

• A gene that is never expressed in the phenotype

• A gene that is only expressed when two copies are present

• A gene that is expressed only in the presence of a recessive gene

What is a phenotype?

• The genetic makeup of an organism

• The physical appearance or traits of an organism

• The number of chromosomes in a cell

• The process of cell division

Which of the following is an example of a recessive trait?

• Brown eyes

• Blue eyes

• Dark hair

• Freckles

How do alleles contribute to an organism's phenotype?

• They determine the number of cells in an organism

• They influence the traits that are expressed

• They control the organism's diet

• They determine the organism's lifespan

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

If a pea plant has one allele for tall stems (T) and one for short stems (t), what is the phenotype if tall is dominant?

• Short stems

• Medium stems

• Tall stems

• No stems

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

What is the term for a gene that is not expressed in the presence of a dominant gene?

• Dominant

• Recessive

• Phenotype

• Allele

Which of the following best describes Gregor Mendel's contribution to genetics?

• He discovered DNA

• He developed the theory of evolution

• He identified the basic principles of heredity

• He invented the microscope

If an organism has two identical alleles for a trait, what is this condition called?

• Heterozygous

• Homozygous

• Dominant

• Recessive