Chapter 2.6 Cell Division .... Flashcards
What’s mitosis ?
3
Type of nuclear division that produces daughter cells genetically identical to each other and to the parent cell .
What’s the order Of the cell cycle starting with M phase ?
1-M phase 2-G0 phase 3-G1 phase 4-Synthesis 5-G2
What happens in M phase ?
3
- cell growth
- PMAT
- Cytokinesis
What happens in G0 phase ?
3
Apoptosis
Differentiation
Senscene
What happens in G1?
4
- cells growth
- Organelles DUPLICATE
- Biosynthesis
- P53 suppressor ( Tumour suppressor)
What happens in synthesis phase ?
2
- DNA Replicates
- Identical sister chromatids
What happens in G2 ?
1
GROWTH
What are the checkpoints ?
3
1- Metaphase checkpoint
2-G1 checkpoint
3- G2 checkpoint
What’s the purpose of the checkpoints?
4
- Prevent uncontrollable division (cancer )
- Detect / repair damage
- ensure cell cycle isn’t reversed
- ensure DNA is duplicate ONCE
What does metaphase checkpoint do ?
1
- cell checks that all chromosomes are attached to spindle before mitosis can continue !
Why do we need mitosis ?
3
- growth
- tissue repair
- Asexual reproduction ( amoeba , paramecium )
What happens in interphase ( mitosis )
3
- cell prepares for cell division
1-organelles divide
2-DNA unravels
3-ATP Content rises
What happens in Prophase ( mitosis ) ?
4
- chromosomes shorten and thicken
- Nuclear envelope breaks down
- Centriole divides and moves to opposite end of cells
- Cytoskeleton TUBULIN threads form
What happens metaphase ( mitosis ) ?
3
- chromosomes line up
- chromatids attach to spindle
- attached by centromeres
What happens in anaphase ?
Chromatids ?
3
1- centromere divides
2-sister chromatically pulled apart by motor protein
What happens telophase ?
3
1-separated chromosomes reach opposite poles
2-new nuclear envelope forms
3-cell contains 2 NUCLEI GENETICALLY IDENTICAL TO EACHOTHER
What happens in cytokinesis ?
Animal ?
1
- cleavage furrow ( plasma membrane bends inwards )
What happens in cytokinesis in plant cells ?
1
End plate ( cellulose forms)
What’s meiosis ?
Reduction nuclear division which results in the formation of Gametes ( haploids)
What is the importance of meiosis ?
- genetic variation rises
- this increases he chance for survival
- drives evolution
Where does meiosis occur ?
Gonads ( ovaries and testes)
How does meiosis produce genetic variation ?
When ?
5
1- Crossing over P1
2-Independent assortment ( A1,2)
3-haploid gametes
Outline meiosis briefly ?
4
PMAT 1
Interphase
PMAT2
Cytokinesis
What plane does the second division ( Prophase 2 ) occur ?
At 90* to P1 division
When is the chromosome number halved in meiosis ?
Telophase 1
What’s a stem cell ?
2
Undifferentiated cells which can undergo mitosis to produce specialised cells
How does differentiation occur ?
4
1-some genes are switched off
2-others are expressed more
3-proportion if organelles changes
4-shape change and content change occurs
How is a erythrocyte adapted to its function ?
1- bioconcave disk
2-no organelle
3- no nucleus ( packs with more haemaglobin
4-small and flexible
How are neutrophils adapted to their function ?
2
- lysosomes
- cytoskeleton extends ( flexible shape )
How is sperm adapted ?
- many mitochondria
- acrosomes
- flagella
- haploid
Where in plant do cells differentiate?
Meristem
Adaptation of palisade mesophyll cells ?
2
- many chloroplasts
- thin walls
Root hair cell adaptations ?
4
- large SA
- large vacuole
- thin permeable walls
- extra mitochondria = active transport
Guard cells work ?
4
k+ active transported in
Lowers water potential
Water moves in
Guard cell opens
What are the 4 main tissues ?
ECMN
- epithelial tissue
- connective tissue
- Muscle tissue
- Nervous tissue
What are the two plant tissues?
2
- epidermal tissue
- Vascular tissue
- meristematic tissue
What are the 3 types of cartilage ?
Examples ?
(6)
- Hyaline Cartilage ( c shaped trachea )
- Fibrous cartilage (knee joint )
- Elastic cartilage (outer ear )
What is cartilage?
Type of tissue ?
Connective tissue
How is cartilage formed ?
-chondroblasts secrete extracellular matrix
How does Xylem form from meristematic tissue ?
3
- cambium cells - Xylem vessels
- lignin is deposited in cell wall ( waterproof cell and kill it )
- end cell wall breaks down =continuous Column
Uses for stem cells ?
4
- bone marrow transplant
- Drug Research
- development in biology research
- repair of damaged cells / replacement of lost tissue :
- alzeihmers
- Parkinson’s
- type 1 diabetes
How does yeast replicate ?
2
- budding
- nucleus divides /mitosis
- cell swells in one side - cytoplasm moves into bulge
- bulge pinches of
