cell specialisation and division Flashcards
what are specialised cells?
cells that have structures or adaptations that allow them to do a particular funcition
cytokenisis meaning
cytoplasm splits
what does pluripotent mean?
can differentiate into almost all types of cells
what are stem cells?
unspecialized cells that differentiate into all types of cells in the body
what are the 2 purposes of stem cells?
self renewal (copying)
differentiation (specialising)
what are some uses for stem cells
-bone marrow transplant for leukemia
-treat disease
- fake meat (cow stem cells)
difference between embryonic and adult sten cells
embryonic (3 to 5 days) are pluripotent
adult stem cells aren’t pluripotent
functions of mitosis
- growth, and repair of tissues in multi cellular
- asexual reproduction in multicellular
- binary fission in unicellular
how long does mitosis last (Percentage of cell life)
10%
stages of mitosis (remember pmat)
prophase
metaphase
anaphase
telaphase
what happens in prophase?
pre - dna replicates
what happens in metaphase?
middle - line up on equator of cell
what happens in anaphase?
away- move to poles of cell
what happens in telaphase?
two - parent cell splits into 2 genetically identical daughter cells after cytokenisis
pros of embryonic stem cells
-embryos that are usually wasted are used to help people
-many available
-pluripotent so can cure a wide variety of diseases
cons of embryonic stem cells
-embryo right (no permission, pro life)
-relitavely untested and unreliable
-harm and death to embryo
-long term effect- cancerous?
pros of adult stem cells
-relitevaly safe
-doesnt kill donors
-quick recovery
-Well tried and tested
-no ethical issues in collection (permission given)
cons of adult stem cells
-painful to donors
-operation hazard (infection etc.)
-not pluripotent so depends on disease
difference between chromatids and chromosomes
2 chromosomes joined together to make a chromatid
how many chromosomes in humans?
46 in every cell EXCEPT sex cells ie sperm and egg cells
cell specialisation- red blood cell
-biconcave disc shape
-large surface area
-no nucleus
-contain haemoglobin
why do red blood cells have specialisation?
to be able to carry more oxygen
cell specialisation- muscle cell
-elongated
-lots of mitochondria
why do muscle cells have specialisations?
so they can contract
cell specialisation-fat cell
-contain an energy store
-can increase in size
-very little cytoplasm
why do fat cells have specialisation?
to be able to store energy
cell specialisation- rod cell
-outer segment filled with visual pigment
-many mitochondria
-one end links up with a nerve cell
why do Rod cells have specialisation?
so that you can see colour
cell specialisation- egg cell
-can be enormous (biggest cell)
-half the no. of chromosones
why do egg cells have specialisations?
- half the amount of chromosomes so that when combined sperm it makes a full set
cell specialisation- phloem
-elongated tubular shape with thin walled sieve tubes that have pores at each end in the cross wall and microtubules that extend between sieve material, allowing longitudinal flow of material
cell specialisation - nerve cell
-long, thin
-form connections with neurones and muscle cells
-carry electrical impulses
why are nerve cells specialised?
so they are able to carry messages around the body like an electrical circuit
why are palised cells specialised?
help with photosynthesis
cell specialisation- palised cell
-regular shape to pack tightly together
-many chloroplasts containing chlorophyll
cell specialisation- sperm cell
- half chromosomes bc it’s a sex cell
- acrosome contains digestive enzymes
-many mitochondria
-long tail
why are sperm cells specialised?
so they can swim to egg cells, penetrate the cell wall and fertilise the egg cell
cell specialisation- guard cell
Banana shape, found in pairs, contain chloroplast, ability to change shape
cell specialisation- xylem
-form long hollow tubes
-wall contain lignin, strengthening material
-dead no cell contents
cell specialisation -root hair cell
-thin cell wall
-large surface area
-many mitochondria for respiration
cell organisation
cell - tissue - organ - organ system - organism
what is a tissue?
a group of cells with a particular function
many tissues have lots of similar types of cells to enable the tissue to fuction
what is an organ?
tissues grouped together to carry out a specific function
what is binary fission?
the form of cell division used by prokaryotes to reproduce asexually
