Genetics

How many chromosomes do human sex cells have?

23

How many chromosomes do normal humans have?

46

What is a Punnett square?

A Punnett square is a chart that shows all the possible combinations of alleles that can result from a genetic cross.

What is a dominant allele? How are dominant alleles written?

A dominant allele is an allele whose trait always shows up in the organism when the allele is present. It is written XX or Xx.

What is a hybrid?

A hybrid is heterozygous

What is a recessive allele? How are recessive alleles written?

A recessive allele is an allele that is masked when a dominant allele is present. It is written xx.

What are alleles?

Alleles are the different forms of genes.

What are the ratios of the offspring from the cross of two hybrids? List the genotypes and phenotypes

BB~25% Dominant~75% Bb~50% Recessive~25% bb~25%

Where are genes located?

Genes are located on your DNA.

What is a gene?

Genes are the set of information that controls a trait; a segment of DNA on a chromosome that codes for a specific trait.

What is genetics?

Genetics is the scientific study of heredity.

Define genotype

Genotype means the genetic make-up of an organism.

Who is Gregor Mendel?

Gregor Mendel was a priest who's hobby was studying plant traits (pea plants)

What are heterozygous alleles? How are heterozygous alleles written?

Heterozygous alleles are when there is on dominant allele and one recessive. They are written Xx.

What are homozygous alleles? How are homozygous alleles written?

Homozygous alleles are when the two alleles are the same. They are written XX or xx.

What is meiosis?

Meiosis is the creation of sex cells

Describe Mendel's experiments. What did he discover?

Mendel looked at the traits of pea plants. He crossed two purebred plants and found in the first generation all were tall. In the second generation one was short and three were tall.

Define phenotype

Phenotype means the physical characteristics of an organism.

What is probability?

Probability is a number that decries how likely it is that an event will occur.

What is a trait?

Traits are a characteristic that an organism can pass on to their offspring through its genes.

How do dominant and recessive alleles work?

When a dominant allele is present it will show itself. A recessive allele will only show itself when there are two.