genetics

What is the scientific study of heredity called?

genetics

What is a genetic trait?

A specific characteristic determined by genes.

What are alleles?

Different forms of a gene.

What are gametes?

The formations of sex cells.

How many alleles does a gamete have for a single gene?

One.

How many alleles do offspring inherit from their parents?

One from each parent.

What does it mean for an organism to be homozygous for a particular trait?

Having two of the same allele.

What must an allele be if a particular form of a trait is always present when the allele controlling it is present?

Dominant.

What does a genotype represent?

The type of genes you have (e.g., TT, Tt, or tt).

What does a phenotype represent?

The physical trait made by genotype (e.g., short or tall).

What is the principle of independent assortment?

Alleles for separate traits are inherited independently during gamete formation.

What did Mendel's dihybrid cross prove?

Genes for seed shape and seed color are inherited independently.

What is the phenotypic ratio when crossing a heterozygous tall plant with a homozygous short plant?

50% tall: 50% short.

True or False? Homozygous organisms are true-breeding for a particular trait.

True.

True or False? Plants with the same phenotype always have the same genotype.

False.

What is incomplete dominance?

One allele is not completely dominant over another; the heterozygous phenotype is between the two homozygous phenotypes.

What is codominance?

Both alleles contribute to the phenotype of the organism.

What are multiple alleles?

Genes that have more than two alleles.

What is polygenic inheritance?

Two or more genes control a trait.

What is a true statement about Mendel's F1 cross?

A dominant allele masked the corresponding recessive allele.

What is the significance of homologous chromosomes?

They contain the same genes in matching pairs with one from each parent.

True or False? Genes that are closer together are more likely to be separated by a crossover event in meiosis.

False.

how does a tetrad form in prophase 1 of meiosis?

they exchange portions of their chromatids in a process called crossing over. each chromosome pairs up with its corresponding homologous chromosome.

what results from the process of crossing-over during prophase I?

new combinations of alleles

Prophase I (Meiosis)

homologous chromosomes pair up and form tetrads, crossing over occurs

Metaphase I (Meiosis)

homologous pairs (tetrads) align along the center of the cell, with independent assortment

Anaphase I (Meiosis)

Spindle fibers move homologous chromosomes to opposite sides of the cell

Telophase I and Cytokinesis (Meiosis)

Chromosomes gather at the poles of the cells. the cell divides resulting in 2 haploid daughter cells

Prophase II (Meiosis)

Chromosomes condense again in both daughter cells, and the nuclear envelope breaks down

Metaphase II (Meiosis)

Chromosomes (each consisting of two sister chromatids) line up in the middle of the cell

Anaphase II (Meiosis)

Sister chromatids separate

Telophase II and Cytokinesis

A nuclear envelope forms around each set of chromosomes. the cytoplasm divides.

What is Meiosis? What is produced?

A type of cell division by which gametes (eggs and sperm) are formed, includes two rounds of cell division to produce 4 daughter haploid cells from a single diploid cell.