nucleus
contains genetic material enclosed in a nuclear membrane
cytoplasm
liquid substance in which chemical reactions occur, contains enzymes and organelles
cell membrane
controls what enters and exits the cell
mitochondria
where aerobic respiration occurs, proving energy for the cells
ribosomes
site of protein synthesis within the rough endoplasmic reticulum
chloroplasts
site of photosynthesis containing chlorophyll
permanent vacuole
contains cell sap, found within cytoplasm and improves cell rigidity
cell wall
a wall of cellulose that provides strength to the cell
which of these is found ONLY in animal cells?
nucleus, cytoplasm, cell membrane, mitochondria, ribosomes
which of these is found ONLY in plant cells?
chloroplasts, permanent vacuole, cell wall
specialised cells
cells that have developed certain characteristics to carry out particular functions
how do cells specialise?
they undergo differentiation
differentiation
process involving the cell gaining new sub-cellular structures for it to be suited to its role
differentiation in animals
mostly only once
differentiation in plants
most cells can retain this ability
specialised cells in animals
sperm cells
nerve cells
muscle cells
sperm cells
function: carry male's DNA to the egg cell for reproduction
streamlined head and long tail for swimming
many mitochondria to supply energy to move
acrosome with digestive enzymes to break down outer layers of egg cell
nerve cells
function: transmit signals from one place to another in the body
muscle cells
function: specialise to contract and expand quickly
specialised cells in plants
root hair cells
xylem cells
phloem cells
root hair cells
function: take up water by osmosis and mineral ions by active transport
large surface area for more absorption
permanent vacuole to speed up movement
mitochondria for energy for active transport
xylem cells
function: transports water and mineral ions from roots to shoots
phloem cells
function: carries products of photosynthesis to all parts of the plant
stem cell
undifferentiated cell that can undergo division to produce many similar cells
types of stem cells
embryonic
adult stem cells
meristems (plants)
embryonic stem cells
form when egg and sperm fuse to form zygote
can differentiate into any type of cell
can be cloned
could replace insulin-producing cells
adult stem cells
if found in bone marrow can form many types of cells
meristems
found in root and shoot tips
can differentiate into any type of plant
can differentiate throughout plant life
can be used to make plant clones
benefits of stem cells in medicine
replace damage cells
bone marrow transplants (treat blood cell cancers)
can grow organs for transplant
no rejection (if made from patient)
allows testing without animals
risks of stem cells in medicine
ethical issues (unused embryos)
no guarantee of success
possible long term effects
mutations
difficult to find donors