Final Exam chapt 10

Explain Gregor Mendel’s contribution to genetics

Through his experiments with garden peas, he discovered the basic principles of heredity and formulated several key genetic laws

What are dichotomous traits?

Only 2 character traits exmpl: short or tall

What is a true breeding plant?

always produce offspring that look identical to the parents

Explain the P, F1, and F2 generations in Mendel’s hybridization experiments

P1: parent generation of true breeding plants

Explain the P, F1, and F2 generations in Mendel’s hybridization experiments

F1: the direct offspring of the P1 cross.

Explain the P, F1, and F2 generations in Mendel’s hybridization experiments

F2: offspring produced by crossing two F1 individuals with each other

What is an allele

a specific version of a gene that exists at a particular location on a chromosome and contributes to an organism’s traits.

Dominant allele

alleles that mask others – often designated with capital letters. Example: P for purple flower

Recessive allele

alleles that are masked by others – often designated
with lower case letters. Example: p for white flower

Genotype

organisms’ genetic makeup

Phenotype

the observable expression of that genetic information, influenced by both genes and the environment.

Homozygote

when both alleles for the same trait are the same.
Example: PP or pp

Heterozygote

when alleles for the same trait differ. Example Pp

Incomplete Dominance

neither allele is dominant, there is a blending

Codominance

two alleles affect the phenotype in separate, distinguishable ways

multiple alleles

three or more alleles for a gene exist in a population

Mendel’s First Law: The Law of Segregation

• Heredity is particulate
• Each true breeding parent carries 2 hereditary particles for
each trait.
• Particles come apart during gamete formation such that each
parent passes only one particle or the other of a pair into
each of their gametes.
• Hereditary particles are then recombined randomly during
fertilization to produce offspring

Mendel’s Second Law: The Law of Independent Assortment

Segregation and recombination of alleles for one trait has no effect on
segregation and recombination of alleles for other traits

EPISTASIS

genetic phenomenon where the expression of one gene is masked or suppressed by another gene, leading to complex inheritance patterns.

Explain the chromosomal theory of inheritance and name the individuals credited with describing it

(a) Walter Sutton and (b) Theodor Boveri • During meiosis, chromosome pairs migrate as discrete
structures
• Each parent synthesizes gametes that contain only half their
chromosomal complement
• Even though male and female gametes (sperm and egg)
differ in size and morphology, they have the same number of
chromosomes, suggesting equal genetic contributions from
each parent
• The gametic chromosomes combine during fertilization to
produce offspring with the same chromosome number as
their parents

What is non-disjunction?

the failure of chromosomes to separate properly during cell division, leading to cells with abnormal numbers of chromosomes.

What is aneuploidy and what are its consequences?

abnormal number of chromosomes. health issues, including genetic disorders, developmental delays, and an increased risk of cancer due to chromosomal imbalances.

What is polyploidy and what are its consequences?

having more than two sets of chromosomes. affecting pants & organisms evolution, adaptation, and agricultural applications.

What is a Barr body?

an inactivated, condensed X chromosome found in the nuclei of female mammalian somatic cells, appearing as a dense, dark-staining spot at the nuclear periphery.

Describe the alterations to chromosome structure that can occur deletion,

deletion occurs when a segment of a chromosome is lost, reducing or eliminating genetic material.

Describe the alterations to chromosome structure that can occur (duplication,

duplication happens when a segment of a chromosome is copied, resulting in extra copies of genetic material.

Describe the alterations to chromosome structure that can occur , inversion,

inversion occurs when a segment of a chromosome breaks in two places, the segment is reversed, and reinserted.

Describe the alterations to chromosome structure that can occur translocation

translocation happens when a piece of one chromosome breaks off and attaches to another chromosome.