The Cell Division: Understanding Mitosis and Meiosis Flashcards
What are the two main processes of cell division?
Mitosis and meiosis
What is the primary purpose of cell division?
Essential for growth, development, and tissue repair in organisms
Define somatic cells.
Body cells that continuously divide, producing new cells daily (e.g., blood, skin)
What is apoptosis?
Programmed cell death
List the functions of apoptosis.
- Reduces cell numbers
- Removes unnecessary tissue during development
- Prevents cancer
What is the cell cycle?
Series of stages from one cell division to the next
What are the phases of the cell cycle?
- Interphase
- Mitotic Stage
What occurs during interphase?
- G1: Cell grows
- S: DNA replication
- G2: Prepares for mitosis
What happens during mitosis?
Division of the nucleus
What is cytokinesis?
Division of the cytoplasm
What is the G1 checkpoint responsible for?
Checks for DNA damage; apoptosis if damaged
What does the G2 checkpoint confirm?
Confirms DNA replication; apoptosis if errors exist
What is the purpose of the M checkpoint?
Ensures proper chromosome alignment before division
How is the cell cycle regulated?
Governed by internal and external signals
What role do growth factors play in the cell cycle?
Stimulate cell division
What are proto-oncogenes?
Genes that promote cell cycle progression; mutations can lead to cancer (oncogenes)
What are tumor suppressor genes?
Inhibit the cell cycle and promote apoptosis; mutations lead to unregulated growth
What is chromatin?
DNA and proteins that form chromosomes
Define diploid cells.
Cells with two sets of chromosomes (e.g., human somatic cells)
Define haploid cells.
Cells with one set of chromosomes (e.g., gametes)
What is the purpose of meiosis?
Reduces chromosome number for sexual reproduction
How many divisions occur during meiosis?
Two divisions, leading to four genetically diverse haploid cells
What is genetic variation in meiosis achieved through?
- Crossing-over
- Independent assortment
What is the difference between mitosis and meiosis?
- Mitosis: One division, two identical diploid cells
- Meiosis: Two divisions, four non-identical haploid cells
What occurs during fertilization?
Haploid sperm and egg combine to form a diploid zygote
What is spermatogenesis?
Meiosis in males, producing sperm
What is oogenesis?
Meiosis in females, producing eggs
What is a centromere?
The region of a chromosome where sister chromatids are held together
What are spindle fibers?
Microtubules that separate sister chromatids during mitosis and meiosis
What is a cleavage furrow?
The indentation that forms in the cell membrane during cytokinesis in animal cells
What is a cell plate?
The structure that forms during cytokinesis in plant cells
