Chromosomes and Inheritance Lecture Notes

These flashcards cover key concepts related to chromosomes and inheritance, focusing on the cell cycle, mitosis, meiosis, and genetic diversity.

What is the Cell Cycle?

The orderly sequence of events through which a cell replicates itself.

What phases make up Interphase?

G1, S, and G2 phases.

What happens during the G1 phase of the Cell Cycle?

The cellular content is replicated, but not the DNA.

What occurs during the S phase of the Cell Cycle?

Duplication of DNA resulting in the formation of identical sister chromatids.

What is Mitosis?

A form of cell division resulting in two genetically identical daughter cells.

What are the two types of cells in multicellular organisms?

Somatic cells and germ cells.

What is the difference between mitosis and meiosis?

Mitosis preserves genetic homogeneity, while meiosis generates genetic heterogeneity.

What is the chromosome number in humans?

2n = 46 chromosomes, n = 23 chromosomes in gametes.

What is fertilization in terms of chromosomes?

The union of two haploid gametes to produce a diploid zygote.

What are sister chromatids?

Identical copies of a replicated chromosome.

What characterizes homologous chromosomes?

They contain the same set of genes but can have different alleles.

Define a metacentric chromosome.

A chromosome with the centromere located in the middle.

What is cytogenetics?

The study of chromosomes.

What is a karyotype?

An analysis of the entire set of chromosomes in a cell.

What occurs during Prophase of mitosis?

Chromosomes condense and become visible.

What happens during metaphase of mitosis?

Chromosomes align at the cell equator.

What are the main stages of mitosis?

Prophase, Prometaphase, Metaphase, Anaphase, Telophase.

What is the role of centrioles during mitosis?

They serve as focus points for microtubules that are part of the mitotic spindle.

Define Meiosis I.

The first division that reduces the chromosome number from 2n to n, known as reductional division.

What are unique features of Meiosis II?

Sister chromatids separate; it maintains the haploid number.

How does meiosis contribute to genetic diversity?

Through independent assortment and crossing over.

What is the difference between somatic cells and germ cells?

Somatic cells undergo mitosis; germ cells undergo meiosis to produce gametes.

What happens during Anaphase II?

Centromeres divide, and sister chromatids move to opposite poles.

What is cytokinesis?

The final stage of cell division where the cytoplasm divides, producing daughter cells.

What happens during Telophase I?

The nuclear envelope reforms, spindle fibers disappear, and cytokinesis occurs.