Biology: Page 9

Flashcards covering key genetics concepts, including crossing over, independent assortment, cancer, vocabulary, Mendelian genetics, and Punnett squares.

Describe crossing over.

Crossing over: Certain chromatids overlap, trading genetic material with one another.

Describe independent assortment.

Independent Assortment: When two or more characteristics are inherited, individual hereditary elements assort independently during gamete production, giving different traits an equal opportunity of occurring together.

What is cancer?

Cancer is when abnormal cell division occurs.

What causes cancer?

Genetic mutations cause cancer by altering the cell's code, preventing it from self-destruction.

How is cancer different from regular cell growth and replication?

Cancer cell growth and replication is unregulated and continuous, unlike regular cell growth.

Define allele.

An allele is an alternative form of a gene.

Define dominant.

A dominant trait is always expressed if the allele is present.

Define recessive.

A recessive trait is only expressed if two recessive alleles are present.

Define homozygous.

Homozygous: both alleles of a gene are the same.

Define heterozygous.

Heterozygous: The alleles of a gene are different.

Define genotype.

Genotype describes the alleles that an organism contains.

Define phenotype.

Phenotype describes the physical characteristics displayed by an organism.

Who was Gregor Mendel and what is he known for?

Gregor Mendel was an Austrian monk who laid the foundation for the discovery of inheritable genes and heredity.

Explain how to complete a Punnett square for a trait that is autosomal and follows normal Mendelian rules.

Set up a 2x2 grid, placing one parent's alleles across the top and the other parent's alleles down the side. Fill in each box with the combination of alleles from its row and column to determine the possible genotypes of the offspring.

How would you determine phenotypes from a Punnett Square Example: Hair Color (H-Brown Dominant,h-Blond Recessive)

Hh-Brown Hair: 50%, hh-Blond Hair: 50%

What does co-dominance mean?

Co-dominance is a relationship between two versions of a gene. Individuals receive one version of a gene (allele) from each parent. If the alleles are different, the dominant allele will usually be expressed, while the effect of the other allele, called recessive, is masked. In codominance, however, neither allele is recessive and the phenotypes of both alleles are expressed.

Explain how to complete a Punnett Square for blood types.

Blood type is determined by three alleles A, B, and O, with A and B being co-dominant and O recessive. Set up the Punnett square based on the parents' genotypes (e.g., AO x BO) and determine the possible blood types of the offspring (OO, AO, BO, AB).

Explain how to complete a Punnett Square for a trait that is autosomal and shows incomplete dominance.

Incomplete dominance is a form of intermediate inheritance in which one allele for a specific trait is not completely expressed over its paired allele. This results in a third phenotype in which the expressed physical trait is a combination of the phenotypes of both alleles. Set up the Punnett square based on the parents' genotypes (e.g., CRCW x CRCW) and determine the possible genotypes and phenotypes of the spring(CRCR (red), CWCW (white), CRCW (pink).)