Lecture 1 Flashcards
What is cell division?
The process by which cells make more cells
Why does cell division occur?
- Growth
- Cell replacement
- Healing
- Reproduction
The two processes of cell division?
Mitosis or Meiosis
Mitosis
Occurs in hair stem cells
Meiosis
Occurs in germ or sex cells
What are Mitotic cells in an adult considered to be?
Stem Cells
Characteristics of Eukaryotyes
Genome is large and linear and DNA is in nucleus
Characteristics of Prokaryotes
Genome is small and circular and DNA is in cytoplasm
What does interphase consist of?
- G1 phase
- S phase
- G2 Phase
- G0 Phase
What happens in G1 (gap 1) phase?
Growth, cellular metabolism
What happens in S phase?
DNA replication (chromosome duplication)
What happens in G2 phase?
Preparation for Mitosis
What happen in M phase (mitosis)?
chromosomal separation and cytokinesis
What is Interphase?
The time between successive mitoses (G1 + S + G2)
What is quiescent?
Cells that are not actively dividing (entering a G0 state)
How many pairs of chromosomes do humans have?
23 Chromosomes
How many pairs of sex chromosomes do humans have?
1 pair
What are homologous chromosomes?
Same chromosomes before and after DNA replication
What happens during mitotic cell division?
A single parent cell divides into two daughter cells
What are the phases in order of Mitotic Cell Division?
Interphase, Prophase, Metaphase, Anaphase, Telephase
What happens during prophase?
Chromosomes condense and centrosomes radiate microtubules and migrate to opposite poles
What happens during pro metaphase?
Microtubules of the mitotic spindle attach to chromosomes
Nuclear envelope starts to break down
What is a Kinetochore?
Large protein assemblies that connect chromosomes to microtubules of the mitotic and meiotic spindles in order to distribute the replicated genome from a mother cell to its daughters
What happens during metaphase?
Chromosomes align in the centre of the cell (equatorial plate)
