nature and variety of organisms Flashcards
what is diffusion
the net movement of particles from an area of high concentration to an area of low concentration
what is osmosis
the net movement of water molecules across a partially permeable membrane from a region of high water potential to a region of low water potential
what are two key features of stem cells
they are able to differentiate into specialised cells
they can divide by mitosis to form more cells
how are embryonic stem cells made
when the zygote goes through mitosis lots of times it forms an embryo which contains lots of embryonic stem cells
why are embryonic stem cells important
they can differentiate into ant type of cell
where in the body are adult stem cells found
bone marrow
why are adult stem cells different to embryonic
they cant differentiate into anything
can only differentiate into blood cells
where are plant stem cells found
meristems
what are the 5 kingdoms of life
plants
animals
protoctists
fungi
bacteria
what is the key difference between prokaryotic cells and eukaryotic cells
prokaryotic - doesn’t have a nucleus
eukaryotic - has a nucleus
is bacteria eukaryotic or prokaryotic
prokaryotic
what is saprotrophic nutrition
an organism secretes digestive enzymes out of their body, onto the food which break down + digest the food
they then absorb the small nutrients into their cells
what is mycelium made out of and where is it found
tiny thread like structures called hyphae
some fungi have bodies made out of mycelium
in osmosis, does water move against the concentration gradient or down it
moves down the concentration gradient (from high to low)
what would happen to red blood cells if placed in pure water
gain water and swell
water moves down the concentration from the pure water to inside of the cell
what is the role of mitochondria
the site of aerobic respiration so release energy for the cell
what is excretion
removal of metabolic waste
what are tissues
a group of similar cells that work together to carry out a particular function
what is an organ
a group of different working together to perform a common function
what are the steps of using stem cells in treatment
extract embryonic stem cells from early embryos
grow the stem cells in a laboratory
stimulate them to differentiate into any type of specialised cell needed
give them to a patient to replace their faulty cells
examples of conditions where stem cells can be used medically
type 1 diabetes (damaged pancreas cells)
paralysis (damaged nerve cells)
sickle cell anaemia (misshapen red blood cells)
drawbacks of embryonic stem cells in stem cell therapy
risk of rejection - persons immune system can identify cells as forgien
limited supply - as they come from embryos
some people have ethical objections to it
advantages of using adult stem cells rather than embryonic in stem cell therapy
no risk of rejection - as they’re taken from the patient themselves
no in limited supply - as come from the patient
risks of using stem cells in medicine
stem cells could get infected with a virus whilst in the laboratory which would then infect the patient
they divide very quickly by mitosis - could divide uncontrollably and develop into a tumour
what is active transport
movement of molecules across a cell membrane against their concentration gradient
from an area of low concentration to high
requires energy from the cellular respiration
