BIO 101 Ch10 Patterns of Inheritance

What is an allele?

A version of a gene. You inherit one allele for each gene from each parent.

Genotype vs phenotype?

Genotype is the alleles you carry (like Bb). Phenotype is the observable trait (like brown eyes).

Homozygous vs heterozygous?

Homozygous: two identical alleles (BB or bb). Heterozygous: two different alleles (Bb).

Dominant vs recessive?

A dominant allele shows when at least one copy is present. A recessive allele only shows when two copies are present.

How is each allele passed on?

Each parent passes one allele per gene, and which one is passed is essentially random for each gamete.

What is a Punnett square?

A grid that predicts the possible genotypes of offspring from the parents' gametes.

Bb x Bb cross: genotype and phenotype ratios?

Genotypes 1 BB : 2 Bb : 1 bb. Phenotypes 3 dominant : 1 recessive.

Bb x bb cross: ratio?

1 Bb : 1 bb, so 1 dominant : 1 recessive phenotype.

What is a test cross?

Crossing an unknown dominant individual with a homozygous recessive to find out its genotype.

What is incomplete dominance?

The heterozygote is a blend of the two homozygotes, like red and white flowers making pink.

What is codominance?

Both alleles are fully expressed in the heterozygote, like AB blood type.

Blood types and alleles?

Alleles IA, IB and i. IA and IB are codominant and both dominant to i. Type O is ii. Type A is IAIA or IAi. Type B is IBIB or IBi. Type AB is IAIB.

Who is the universal donor and universal recipient?

Type O negative red cells can be given to anyone (universal donor). Type AB positive can receive any type (universal recipient).

Why does blood type matter medically?

A mismatched transfusion triggers an immune attack on the donor cells. Compatibility must be checked.

What is Mendels law of segregation?

The two alleles for a gene separate when gametes form, so each gamete gets one.

What is Mendels law of independent assortment?

Genes for different traits are inherited independently of each other (when they are on different chromosomes).

What is a sex-linked trait?

A trait whose gene is on the X chromosome. Males (XY) express recessive X-linked traits more often because they have only one X.

What is polygenic inheritance?

One trait controlled by many genes, such as height or skin color, giving a continuous range.

How does Dr. Hinn recommend studying Ch10?

It is vocab heavy. Do practice assessments on top of Smartbook before the test.