Cell Division Flashcards
2 Types of cell division
Somatic cell division
Reproductive cell division
How many chromosomes are there in a somatic cell division?
46 chromosomes, 23 pairs
Any precursor cell destined to be a gamete
Somatic cell division
Other term for a gamete
Germ cell
The germ cell/ gamete is composed of what?
Sperm cell and egg cell
The gamete/ egrm cell undergoes what processes?
Mitosis and Cytokinesis
Other term for mitosis
Nuclear division
Other term for cytokinesis
Cytoplasmic division
What does the somatic cell division produce?
2 identical cells (same number and kind of chromosomes as the original cells)
Replaces dead or injured tissue cells and add new ones during tissue growth
Somatic cell division
The period between cell divisions
Interphase
Resting phase of the cell (?)
Interphase
What happens during Interphase?
Interphase is when the cell is not dividing, yet undergoes most of the growing. There is a high state of metabolic activity, and replication of DNA occurs *S Phase)
Phases of Interphase
- G1 Phase
- Synthesis (S) Phase
- G2 Phase
Phase of the cell sensitive to radiation
Radiosensitive
Interphase that is/are radiosensitive
G1 & G2 Phase
Phase that has enough energy to counter radiation
Radioresistant
Interphase that is radioresistant (?)
S Phase
Known to be the relaxed phase
G Phases
Phase where there is no activity of DNA Replication
G Phases; DNA Replication is in the S Phase
Known to build gap/interruptions
G Phases
How many sets of chromosomes are created in Mitosis and Meiosis?
Mitosis: 2 sets (Diploid)
Meisosis: 4 sets (Haploid)
What happens during Mitosis?
Parent cell produces identical cells, chromosomes become visible under light microscope, and 2 sets of chromosomes are distributed into a separate nuclei
Enumerate what happens during Prophase
- Chromatin fibers condense into paired chromatids
- Nucleolus and nuclear envelope disappear
- Each centrosome moves to an opposite pole of the cell
What happens during Metaphase?
Centromeres of chromatid pairs line up at metaphase plate
Responsible for putting the chromosomes at the middle during Metaphase
Metaphase plate
How many number of chromosomes are made during fertilization compared to when they were somatic cells?
Gametes will have the same nuber of chromosomes as somatic cells, while number of chromosomes would double during fertilization.
In this process, each new organism is the result of the union of two different gametes, one produced by each parent
Sexual reproduction
What happens during Telophase?
- Nuclear envelopes and nucleoli reappear
- Chromosomes resume chromatin form
- Mitotic spindle disappears
- Further pulling away, reating a cleavage furrow
What happens during Anaphase?
- Centromeres split
- Identical sets of chromosomes move to opposite poles of the cell (Chromatids move away)
What happens during cytokinesis?
Contractile ring forms cleavage furrow around center of cell, dividing cytoplasm into separate and equal portions
Produces gametes in which the number of chromosomes is reduced by half
Meiosis 1
What does fertilization restore during Meiosis 1?
Diploid number of chromosomes
What processes happen during Prophase 1?
Synapsis
Tetrad
Crossing over
The 2 sister chromatids of each pair of homologous chromosomes pair off
Synapsis
Resulting four chromosomes
Tetrad
Exchange between parts of non-sister (genetically different) chromatids
Crossing over
Explain what happens during Prophase 1
In a process called synapsis, 2 sister chromatids of each pair of homologous chromosomes pair off to form a tetrad. Afterwards, in a process called crossing over, exchange between parts of non-sister chromatids.
