Cell Theory, Mitosis, and Meiosis Study Notes

This set of flashcards covers key concepts from the lecture notes, focusing on cell theory, cell division (mitosis and meiosis), and the implications of chromosomal behavior in heredity and disorders.

What are the key principles of cell theory?

All living organisms consist of cells, cells divide to form new cells, reproduction involves the fusion of two cells.

What is a Karyotype?

A visual display of stained chromosomes arranged by size and banding pattern.

What is an important feature of chromosome structure just before cell division?

Each chromosome has two identical chromatids, joined at a centromere.

What is aneuploidy?

A condition resulting from failure to segregate chromatids properly, leading to an incorrect number of chromosomes.

What are the major phases of the cell cycle?

G1 (growth), S (synthesis), G2 (preparation for mitosis), M (mitosis).

What happens during the G2 to M phase transition?

The cell checks if all DNA has been accurately replicated and if there is DNA damage before entering mitosis.

What are Cyclins and CDKs?

Cyclins are regulatory proteins, and CDKs are enzymes that require cyclins to function at different phases of the cell cycle.

What is the purpose of meiosis?

To produce haploid gametes (sperm and eggs) with half the chromosome number.

What genetic consequence results from nondisjunction during meiosis?

Nondisjunction can lead to Down Syndrome (Trisomy 21) due to the presence of an extra chromosome.

What separates during Meiosis I?

Homologous chromosomes are separated, but sister chromatids remain together.

What is crossing over, and when does it occur?

An exchange of DNA between non-sister chromatids of homologs that occurs during Prophase I of meiosis.

What characterizes a haploid-dominant life cycle?

Most of the organism's life cycle is spent in a haploid state.

What do odd-numbered polyploids struggle with during meiosis?

Odd-numbered polyploids cannot match chromosomes into homologous pairs, leading to sterility.

What is one of the advantages of balanced polyploidy?

Balanced polyploidy ensures a 1:1 ratio of chromosomes, allowing normal development and function.