Cell Division Flashcards
G1
Synthesis:
- protiens
-new organelles like centrosomes
- cell size increases
G1 CHECKPOINT
Checks for cell size, nutrients, growth factors, and DNA damage.
S
Synthesis phase: DNA replicated via semi conservative replication, each of the 46 chromosomes is duplicated.
G2
Synthesis of molecules need for cell division.Duplicated DNAchecked for damage. cell increases in size
G2 CHECKPOINT
Checks for cell size, dna replication, and dna damage.
SPINDLE ASSEMNLY CHECKPOINT
Checks for chromosome attachment to spindle.
What carries out checkpoint checks?
Cyclins
Order the stages of mitosis
Prophase
Metaphase
Anaphase
Telophase
PROPHASE
DNA is condensed
Sister chromatids visible.
METAPHASE
Nuclear envelope has broken down
Centrioles move to poles of the cell.
Centrioles anchor spindle fibres.
Sister chromatids line along the middle of the cell.
ANAPHASE
Spindle fibres attach to centrosomes and get shorter.
This pulls the chromatids apart.
Centrosome splits with the division of chromatids.
Chromatids now called chromasomes.
Migrate to opposite ends of the cell.
Identical copy of full set of chromosomes at either end of the cell.
Cytoplasm starts to pinch in middle.
TELOPHASE
Nuclear envelope re formscaround each set of chromosomes.
Division spindle breaks down.
Pinch now deepened and called a cleavage furrow.
Chromosomes start to dispurse like before mitosis.
CYTOKENISIS
- not part of mitisis
- part where cell actually splits.
- daughter cells will now move into G1
Cytokenis is not the same in plant cells…
- instead of the cytoplasm splitting apart, they have a cell plate that forms down the middle of the cell.
- only cells that undergoe mitosis are MERISTEM cells
- plant cells do not have centrioles.
chromatin
what constitutes chromosomes
Bivalent
A replicated homologous pair. Two replicated chromosomes, one from each parent (4 sister chromatids)
Homologous
Same length, sequence and centromere location.
Prophase 1
Chromosomes condense, and homologous chromosomes pair up to make bivalents.
Metaphase 1
Bivalents line up at a random orientation.
Anaphase 1
Spindle fibres shorten. Bivalents pulled apart, sister chromatids remain joined together.
Telophase 1
nuclear envelope reforms. cleavage furrow.
Prophase 2
Condenses, nuclear envelope breaks down.
Metaphase 2
Chromosome line up and spindle fibres attatch.
Anaphase 2
Spindle fibres shorten, chromosomes pulled apart.
Telophase 2
Chromatids dispurse again, nuclear envolope reforms.
Chiasmata/ recombination
Bivalents form, DNA gets tangled, snaps off, and rejoins. Results in a different combination of alleles.
Independant Segregation/ random assortment
Bivalent orientation is random. meaning a random assortment of chromosomes at each pole after anaphase stage. Results in a different combination of chromosomes after anaphase 2.
Neutrophil (4)
-White blood cell
-granules for energy storage
-Lysosomes contains hydrolytic enzymes
- multilobulated so it can squeeze through gaps
Sperm Cell (5)
- acrosomal vessel with enzymes
- mitochondroin for energy
- streamlined shape
- flagellum for movement
- nucleus contains half genetic info for zygote.
Erythrocyte (4)
- biconcave shape
- no nucleus, more room for oxygen
- haem group binds to oxygen
- small snd flexible to fit into capillaries
Palisade cell (2)
chloroplasts for photosynthesis
a large vacuole to maintain turger pressure
Guard cell (3)
- mitochondria for active transport
- large surface area for osmosis
- minerals and ions in cytoplasm so water enters the cell
Squamous Epithelium (1)
one cell thick, so gas exchange is quick.
Ciliated epithelium and goblet cells (2)
- cilia for movement of mucas.
- goblet cells to broduce the mucus
Muscle tissue (1)
actin and myosin for muscle contractions and shortenings.
Cartilage (1)
Firm but flexible to allow movement.
Epidermal (2)
- made of epithelial cells and guard cells.
- stomata to allow gases to enter and exit.
Xylem (2)
- gaps in the end of cells for water
- lignin so the walls are waterproof
Phloem (2)
- sievtube is like a really long steaw that allows movement.
- companion cells that do all ghe hard work.
Totipotent
has the total and utter potential to become anything.
Pluripotent
can differentiate into all tissue types but not whole organisms. differentiate into any adult cell.
Multipotent
Only differentiate into a range of cells within a certain type of tissue.
can you distinguish the difference between genes and alleles?
Alleles are all the different types of certain gene e.g vanilla coca cola is a type of coca cola drink.
what do plant cells not have?
centrioles
What plant cells can undergoe mitosis?
Meristem cells
Homologous chromosomes
A pair of chromosomes, one from ma and one from pa
What is the number of cells that an embryo is totipotent for?
up to 8 or 16 cells (its first mitotic divisions)
potential use of stem cells…
to treat diseases
list diseases that stem cells could potentially treat..
- heart disease
- type 1 diabetes
- parkinsons disease
- alzheimers disease
- macular degeneration
- spinal injuries
ways stem cells are already used…
- burn treatment
- drug trials- new drugs can be tested in a culture of stem cells
- developmental biology - the study of growth and why things sometimes go wrong.
adult stem cells are…
multipotent
a cell divides [direction] during cell division
longitudinally *like vertically
to diversify their genetics, bacteria undergoe
horizontal gene transfer
when are chromosomes maximally condensed?
metaphase
neutrophil features
contain lysosomes filled with hydrolytic enzymes called lysozymes
have a multilibulated nucleus
which cells undergoe phagacytosis
neutrophils
macrophages
checkpoints
- at G1, G2, S phase and during mitosis (to check for attachment of chromosomes to spindle fibres)
unipotent cells
can divide to produce only one type of cell
Multipotent
can develop into a limited number if cells
what happens when a cell becomes specialised?
Some genes become activated. those activated genes are expressed.
what happens after genes are activated in cell differentiation?
the expressed gene is transcribed into mRNA, and a protein is formed.
The presence of these proteins means the cell has become specialised.
which stem cells can be used to treat human disorders and diseases?
pluripotent
what is IPs
induced pluripotent stem cells. made from specialised somatic cells by activating genes using appropriate protein transcription factors
developmental biology
used to learn more about how organs are formed. inform us on abnormalities and why organs fail.
which stages in the cell cycle are common targets for anti cancer drugs?
G1
S
a word to describe multiplication of cells
proliferation
a word to describe multiplication of cells
proliferation
where do spinfle fibres bind to an a centromere
kinetochore
monocytes vc macrophages
macrophages are monocytes in tissue
