bio test rn brochacho (copy)

What is codominance in genetics?

A condition where both alleles in a heterozygous organism are fully expressed.

What is incomplete dominance?

A form of inheritance where the heterozygous phenotype is a blend between both alleles.

What are multiple alleles?

When more than two alleles exist for a trait, with each individual carrying only two.

What are sex-linked traits?

Traits carried on the X or Y chromosome, most commonly the X.

What are sex chromosomes?

The 23rd pair of chromosomes that determine an individual's sex.

What is a polygenic trait?

A trait controlled by two or more genes, often showing a range of phenotypes.

What is a carrier in genetics?

An individual who is heterozygous for a recessive disorder but does not show symptoms.

What is a pedigree?

A diagram used to trace the inheritance of traits through generations.

What is a recessive genetic disorder?

A disorder that appears only when an individual is homozygous recessive.

What is a dominant genetic disorder?

A disorder that appears when an individual has at least one dominant allele.

What is a dominant allele?

The allele that expresses itself over another allele.

What is a recessive allele?

The allele that is masked by a dominant one unless both alleles are recessive.

What does homozygous mean?

Having two identical alleles for a gene.

What does heterozygous mean?

Having two different alleles for a gene.

What is a genotype?

The genetic makeup of an organism.

What is a phenotype?

The physical expression of the genotype.

What is an autosome?

Any chromosome that is not a sex chromosome.

How can you tell the inheritance pattern based on the phenotype of a heterozygous individual?

Mendelian: dominant trait is shown; Codominance: both traits visible; Incomplete dominance: blended trait.

What do RBCs look like in people with homozygous normal genotype (SS)?

Normal-shaped RBCs.

What do RBCs look like in a heterozygous genotype (Ss) for sickle cell anemia?

Both normal and sickle-shaped RBCs.

What do RBCs look like in people with homozygous sickle genotype (ss)?

All RBCs are sickle-shaped.

How many alleles exist for blood type?

Three: A, B, O.

Which blood type alleles are codominant?

A and B are codominant; O is recessive.

What are the genotypes for blood type A?

AA or AO.

What are the genotypes for blood type B?

BB or BO.

What is the genotype for blood type AB?

AB.

What is the genotype for blood type O?

OO.

What sex chromosomes do females have?

XX.

What sex chromosomes do males have?

XY.

Are sex-linked traits usually dominant or recessive?

Recessive.

Which chromosome usually carries alleles for sex-linked traits?

The X chromosome.

Why do males get sex-linked traits more often?

Males have only one X chromosome.

Is a carrier homozygous or heterozygous?

Heterozygous.

Can males be carriers for sex-linked traits?

No, because they only have one X chromosome.

Can males be carriers for autosomal traits?

Yes.

Can females be carriers for sex-linked traits?

Yes.

What is the definition of a polygenic trait?

A trait influenced by multiple genes.

What are examples of polygenic traits?

Height, skin color, eye color.

How is phenotype determined in polygenic traits?

By the additive effect of all the genes involved.

What does 'additive' mean in polygenic traits?

Each allele adds to the expression of the trait.

Which genotype gives darker skin: AABbCc or aabbCC?

AABbCc.

What genotype gives mid-tone skin?

A mix like AaBbCc.

What are some examples of environmental influences on traits?

Sun exposure, nutrition, temperature, chemicals.

Can environment change the genotype of an organism?

No, only phenotype can be influenced.

Why use pedigrees in genetics?

To track inheritance of traits through generations.

What do the different symbols in a pedigree represent?

Squares = males, circles = females, shaded = trait presence.

How can you tell if a trait is recessive in a pedigree?

If it skips generations.

Can you determine relatedness in a pedigree?

Yes, using layout and connections.

Match albinism to its description.

Recessive; lack of melanin pigment in skin, hair, eyes.

Match Huntington’s disease to its description.

Dominant; causes progressive brain deterioration.

Match galactosemia to its description.

Recessive; cannot break down galactose.

Match Tay-Sachs to its description.

Recessive; lipid accumulation in brain cells.

Match cystic fibrosis to its description.

Recessive; leads to thick mucus and related health issues.

Match achondroplasia to its description.

Dominant; a form of dwarfism affecting bone growth.