Cell Division and Meiosis

These flashcards summarize important concepts related to cell division, mitosis, meiosis, and the implications of these processes in biology.

What is the process by which a parent cell divides to produce daughter cells called?

Cell division.

What is cytokinesis?

The splitting of cytoplasm in a parent cell between daughter cells.

In animal cells, what structure helps split the cell membrane during cytokinesis?

A ring of contractile actin and myosin proteins.

What examples demonstrate unequal cytokinesis?

Oogenesis in humans and budding in yeast.

What is the main purpose of mitosis in eukaryotes?

To maintain the chromosome number and genome of cells.

How does meiosis differ from mitosis in terms of chromosome number?

Meiosis halves the chromosome number, producing haploid cells.

What must occur before both mitosis and meiosis?

DNA replication.

What role do histones play in cell division?

They assist in the condensation of DNA by supercoiling.

What is the end result of one complete meiotic division?

Four haploid nuclei are produced from one diploid nucleus.

What is non-disjunction and how does it relate to Down syndrome?

Non-disjunction is the failure of chromosomes to separate properly during meiosis, leading to an extra copy of chromosome 21 in Down syndrome.

What is the function of cyclins in the cell cycle?

Cyclins control the checkpoints of the cell cycle, allowing the cell to proceed to the next phase.

What distinguishes a benign tumor from a malignant tumor in terms of cell behavior?

Benign tumors consist of well-differentiated cells that do not spread, while malignant tumors consist of undifferentiated cells that can metastasize.

What is the mitotic index and why is it significant?

The mitotic index is the ratio of cells in mitosis to the total number of cells in a tissue sample; it helps in assessing cancer cell division rates.

What are bivalents and their significance in meiosis?

Bivalents are pairs of homologous chromosomes that align during meiosis, allowing for genetic recombination.

What does crossing over achieve during meiosis?

It results in genetic variation by swapping alleles between non-sister chromatids.