Cell Cycle and Cell Division Flashcards
- Series of events that occurs in a cell from cell growth and cell division
- Divided into two phases: Interphase & Mitotic Phase
Cell Cycle
- Where cells grow and DNA replication occurs.
- Preparatory phase for cell division
Interphase
Phases and Checkpoints of the Interphase
- G1 Phase
- G1 Checkpoint
- S Phase
- G2 Phase
- G2 Checkpoint
- M Phase
- M Checkpoint
- G0 Phase
- First Gap
- Cell increase in size and volume
- Accumulation of building blocks of chromosomal DNA for S and M phase.
G1 Phase
- Restriction Point
- Determines whether all conditions are favorable for cell division to proceed.
- Inhibited by p53, p21, and Retinoblastoma Protein (Rb)
- Stimulate by Cyclin and Cyclin-Dependent Kinase (CDK)
G1 Checkpoint
- Synthesis of DNA
- Uses energy to synthesize and replicate DNA resulting in the formation of identical molecules - Sister Chromatids.
S Phase
- Second Gap
- Cell increase in size and volume
- Replenishment of energy used in DNA synthesis
G2 Phase
- Stimulated by cyclin and cyclin-dependent kinase (CDK)
- Inhibited by p53, p21, and Retinoblastoma Protein (Rb)
- Ensures that all DNA are completely and correctly replicated.
G2 Checkpoint
- Resting phase or nondividing phase
- A phase where a cell does not prepare to divide
G0 Phase
- Division of the cell nucleus in somatic body cell
- Where two new cells are formed.
Mitosis
Phases of Mitosis and Meiosis
- Prophase
- Prometaphase
- Metaphase
- Anaphase
- Telophase
- Cytokinesis
Cell Cycle:
M Phase:
1. Phase where replicated DNA are condensed to form chromosomes
Prophase
Phase where:
1. Chromosomes become more condensed
2. Each sister chromatid develops a kinetochore
3. Spindle fibers attaches to the kinetochore of sister chromatids.
Prometaphase
Phase where chromosomes align in the middle plane of the cell called the equatorial plane.
Metaphase
Phase where sister chromatids separate and move to opposite poles, this causes the cell to become elongated.
Anaphase
Phase where:
1. Chromosomes reach the opposite poles
2. Nuclear envelope forms around the cytoplasm
Telophase
Phase where cytoplasm divides to form new cells.
Cytokinesis
- Spindle checkpoint
- Occurs during metaphase
- Checks if all spindle fibers are attached to the kinetochore of sister chromatids.
M Checkpoint
Differentiate Haploid and Diploid
- Haploid - have one set of chromatid.
- Diploid - have two sets of chromatids.
Stimulation of the cell cycle by the cyclin and cyclin-dependent kinase (CDK)
Drives the cell through other phases.
Cell Cycle:
Inhibition of the cell cycle by p53 & p21
Inhibits apoptosis
Programmed cell death by causing cell cycle arrest and DNA repair to prevent cancer.
Apoptosis
Inhibition of the cell cycle by retinoblastoma protein (Rb)
- Checks if there is sufficient nutrients and materials in the cell
- Checks if the cell is in proper size
- Nuclear division for gametes
- Divided into two phases
- A single cell divides to form four new cells
Meiosis
Phases of Prophase I in Meiosis I
- Leptotene
- Zygotene
- Pachytene
- Diplotene
- Diakinesis
Phase in Prophase I where chromosomes begin to condense.
Leptotene
Phase in Prophase 1 where the homologous chromosomes will form a synapsis.
Zygotene
Chromosomes from both parents that are exact copies of each other.
Homologous Chromosome
The pairing and twisting of chromosomes around each other
Synapsis
Phases in Prophase I where physical separation of a chromosome region occurs.
Pachytene
Phase in Prophase I where separation of the homologous chromosomes except at the site of cross-over called chiasmata.
Diplotene
Phase in Prophase I where termination of the chiasmata occurs.
Diakinesis
Chromatid number in Interphase
- Before 46
- After 92
Chromatid number after Mitosis
- Before 92
- After 2 Sets of 46
Chromatid number in meiosis
- Before 92
- After Meiosis I: 2 sets of 46
- After Meiosis II: 4 sets of 23
