hayop na Bio Flashcards
Prophase
- DNA condenses into tightly coiled chromosomes
- Nuclear envelope breaks down
- Centrioles move to poles and spindle fibers form
- The nucleolus disappears
- The nuclear membrane breaks apart
- The chromosomes become visible
- The spindle apparatus forms and attaches to the centromeres
Metaphase
- Spindle fibers attach to each chromosome
- Chromosomes align along cell equator
- Second phase of mitosis
- The Nuclear Membrane is completely gone
- The duplicated chromosomes line up along the cell’s equator
Anaphase
- Chromatids separate to opposite sides of cell
- Third Phase of Mitosis
- Diploid cells of daughters chromosomes separate
- They are pushed and pulled toward opposite poles of the cell by the spindle fibers
Telophase
- Nuclear membrane starts to form
- Chromosomes begin to uncoil
- Spindle fibers fall apart
- Nuclear membrane and nucleoli reform
- Cytokinesis is nearly complete
- Cell prepares for finial division
Cytokinesis
- Division of cytoplasm
- Different in animal and plant cells
- The final stage of Mitosis
- The cytoplasm, organelles and nuclear material are evenly split and two new cells are formed
Interphase
G1
Synthesis
G2
Gap 1
- Cell carries out normal functions
- Cell increases in size
- Organelles increase in numbers
Synthesis
- Cell makes a copy of its own DNA
- Synthesis means “the combining of parts to make a whole.”
- By the end of S, cell nucleus contains 2 complete sets of DNA
Gap 2
- Cells continue to carry out normal functions
- Additional growth occurs
- Critical checkpoint (b4 cell goes through mitosis, cell must be adequate size, undamaged cell)
G1 Checkpoint
Reliability if DNA
M Checkpoint
Attachment of each kinetochore to a spindle fiber
G2 Checkpoint
Proper Chromosome duplication
A regular pattern of growth, DNA replication, and cell division in eukaryotic cells
Cell Cycle
Chromosome
- One long continuous thread of DNA
- Consists of numerous genes
How many chromosomes does a person have?
46
Half of chromosome
Chromatid
Each of the 2 thread-like strands into which chromosome divides longitudinally during cell division
Chromatid
Centromere
Point where sister chromatids are joined
P arm
Short arm; Upward
Q arm
Long arm; downward
Telomere
- Tips of chromosome
- Found at ends of DNA molecules and prevent DNA from coming apart
Chromatin
Material of which the chromosomes of organisms other than bacteria are composed, consisting of proteins, RNA and DNA
Interphase
Cell appeared to be at rest
In human cells, How many hours does S, G2, and M stages take?
12 hours
G0’s other name
Quiescence phase
G0
- Cells is neither dividing nor preparing to divide
- Reproductively resting but functional
- “Post mitotic phase”
Quiescence can be reversible or irreversible in
Plant cells
Quiescence is reversible
• Temporary - liver, kidney, stomach cells
Quiescence is irreversible
Non-proliferative (non dividing) cells
Mitosis
- Division of nucleus
- Same full set of DNA
- Somatic cells, except sex cells
External factors
Triggers internal factors that affect cell cycle
Kinases
Enzymes that transfer phospate from one molecule to target molecule
Cyclins
Group of proteins that activates kinases
Apoptosis
Programmed cell death (signals activate genes producing self-destructive enzymes)
Cancer
Common name for diseases characterized by uncontrolled cell division
Benign
Cancer cells remain clustered together
Malignant
Some cell break away or metastasize from the tumor and spread through body
Cancer cells
- came from normal cells that have suffered damage to genes that makes proteins involved in cell division
- damage from radiation, inherited, chemicals, and ultraviolet radiation
- Carcinogens: substance known to cause cancer
- Can be treated with both radiation and chemotherapy
