6.4 Traits, Genes and Alleles

What is are dominant alleles?

Dominant alleles are those that are expressed more often in a population (they are not "stronger" or "better" than recessive alleles).

How are dominant alleles usually expressed (upper case or lower case letter)?

Dominant alleles are usually expressed in upper-case letters.

How are recessive alleles usually expressed (upper case or lower case letter)?

Recessive alleles are usually expressed in lower-case letters.

If a recessive allele helps and organism reproduce but the dominant allele hinders reproduction, which would be more common in the population?

Recessive because the dominant allele would suppress reproduction and you wouldn't have a population.

What can genotypes result in?

Some genotypes result in a protein, others don't. Some genotypes also result in two proteins being made that influence one phenotype.

What is a phenotype?

The observable physical characteristics of a trait.

What is a genome?

A list of all genes in an organism.

What are two letters that could be used to represent and allele?

A or a.

What are alleles A and a similar to?

An isotope in chemistry.

What is a locus?

A genes location on the chromosome.

What is an allele?

A form of a gene.

What is a gene?

A section of DNA.

What is an example of homozygous alleles?

AA or aa.

What are some examples of a genotype?

AA, aa and Aa.

What is an example of a homozygous dominant?

AA.

What is an example of a heterozygous allele?

Aa.

What is an example of a heterozygous dominant?

Aa.

What is the difference between a locus and an allele?

An allele is an alternate form of a gene and a locus is the location of that gene on a chromosome.

Why can't a gene be heterozygous recessive?

Because recessive only happens when both alleles are recessive.

What are genotypes?

Genetic makeup of a specific set of genes.

How many genes do humans have in their genome?

Humans have around 24,000 genes in their genome.

What is the phenotype of AA if it coded for pea shape?

If AA coded for pea shape, "shape" would be the phenotype.

What does it mean if an individual is heterozygous?

If an individual is heterozygous, they have two different alleles for a gene.

What does it mean if an individual is homozygous?

If an individual is homozygous, they have two identical alleles.

What is an example of a homozygous recessive?

aa.

Cystic fibrosis is a recessive disease that causes the production of thick, life-threatening mucus secretions. What is the genotype of a person with cystic fibrosis (CC, Cc, or cc)?

cc.