nature and variety of organisms

Question 1

what is diffusion

Answer 1

the net movement of particles from an area of high concentration to an area of low concentration

Question 2

what is osmosis

Answer 2

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

Question 3

what are two key features of stem cells

Answer 3

they are able to differentiate into specialised cells
they can divide by mitosis to form more cells

Question 4

how are embryonic stem cells made

Answer 4

when the zygote goes through mitosis lots of times it forms an embryo which contains lots of embryonic stem cells

Question 5

why are embryonic stem cells important

Answer 5

they can differentiate into ant type of cell

Question 6

where in the body are adult stem cells found

Answer 6

bone marrow

Question 7

why are adult stem cells different to embryonic

Answer 7

they cant differentiate into anything
can only differentiate into blood cells

Question 8

where are plant stem cells found

Answer 8

meristems

Question 9

what are the 5 kingdoms of life

Answer 9

plants
animals
protoctists
fungi
bacteria

Question 10

what is the key difference between prokaryotic cells and eukaryotic cells

Answer 10

prokaryotic - doesn’t have a nucleus
eukaryotic - has a nucleus

Question 11

is bacteria eukaryotic or prokaryotic

Answer 11

prokaryotic

Question 12

what is saprotrophic nutrition

Answer 12

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

Question 13

what is mycelium made out of and where is it found

Answer 13

tiny thread like structures called hyphae
some fungi have bodies made out of mycelium

Question 14

in osmosis, does water move against the concentration gradient or down it

Answer 14

moves down the concentration gradient (from high to low)

Question 15

what would happen to red blood cells if placed in pure water

Answer 15

gain water and swell
water moves down the concentration from the pure water to inside of the cell

Question 16

what is the role of mitochondria

Answer 16

the site of aerobic respiration so release energy for the cell

Question 17

what is excretion

Answer 17

removal of metabolic waste

Question 18

what are tissues

Answer 18

a group of similar cells that work together to carry out a particular function

Question 19

what is an organ

Answer 19

a group of different working together to perform a common function

Question 20

what are the steps of using stem cells in treatment

Answer 20

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

Question 21

examples of conditions where stem cells can be used medically

Answer 21

type 1 diabetes (damaged pancreas cells)
paralysis (damaged nerve cells)
sickle cell anaemia (misshapen red blood cells)

Question 22

drawbacks of embryonic stem cells in stem cell therapy

Answer 22

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

Question 23

advantages of using adult stem cells rather than embryonic in stem cell therapy

Answer 23

no risk of rejection - as they’re taken from the patient themselves
no in limited supply - as come from the patient

Question 24

risks of using stem cells in medicine

Answer 24

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

Question 25

what is active transport

Answer 25

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