More bio past papers Flashcards
Mitochondria are
the site of AEROBIC respiration!!!!!
Why do you blot the potatoes in that one osmosis experiment?
Get rid of excess water on the surface that is not actually in the cells, otherwise the mass reading would be higher
How does fibre affect your diet?
Aids digestion/prevents constipation
How does protein affect your diet?
More-> growth
How does more fat affect your diet?
Can cause CHD/heart attack/narrowing of arteries
May need a stent
may lead to obesity- a risk factor in type2 diabetes
How does cholesterol affect your diet?
CHD/heart attack/narrowing of arteries
stents/statins
How do carbohydrates affect your health?
good for providing energy
How do you keep safe while handling knives?
cut away from body/use chopping board/keep fingers away from blade
why is “The cover slip is lowered onto the onion epidermis at an angle”?
prevent air bubbles
why is iodine solution added to the onion?
To stain the onion to see parts of the cell
In what ways could you improve the scientific drawing? Non exhaustive
include magnification
continuous lines
don’t draw overlapping cells
wider cell walls
no shading
draw all cells
no gaps between cells
nuclei in right position
label
how would an image look different if you used an electron microscope instead?
more magnified
more detail/higher resolution/see more subcellular structures
black+white
How does mimicry help the hornet moth survive?
it looks like the hornet so predators tricked and avoid eating it
Describe the process of mitosis
DNA replicated
chromosomes pull apart
cytoplasm divides
set of chromosomes in each
new cell are identical
Which environmental conditions would cause the rate of transpiration to be greatest in
a plant?
low humidity high temp
Explain why multicellular organism D requires a respiratory system, but single celled B does not
D has a smaller SA:V ratio
large to meet demands of cells
Why do smaller multicellular organisms (D) have a greater metabolic rate?
D has lagrer SA:V ratio and so will lose
heat more quickly (per unit
volume than E)
so requires greater rate of
respiration
(as) respiration is a (large) part
of metabolism
(so) need to generate more heat
(to keep itself warm)
how is HIV spread?
sexual contact/sharing bodily fluids
Describe the trends of new cases of HIV in men and women between 2010 and 2018
The important thing is not to mention differences between men and women
how to prevent HIV spread?
- better education (into
prevention of spread of HIV) - condoms more widely
available/cheaper - new / better drugs (to prevent
HIV infection / spread) - better / more testing /
identification (of people with
HIV)
process of making a MAB for HIV
HIV antigen injected into mouse
collect mouse lymphocytes that make a
specific AB to HIV antigen
lymphocytes combined with tumour cell to create a
hybridoma which is cloned to create many cells that produce the MAB
Suggest how the monoclonal antibody for HIV helps to prevent a person infected with
HIV developing AIDS.
monoclonal antibody is specific to HIV antigen
monoclonal antibodies attach to HIV antigens
so they can’t bind to human cell
Name two pieces of laboratory equipment the student could have used to prepare
cells to view using a microscope.
(microscope) slide
* cover slip
* dye / stain
* (mounted) needle
* pipette / dropper
* scalpel
* forceps / tweezers
The student tried to look at the cells using the microscope.
Suggest one reason why the student could not see any cells when looking through
part A.
objective lens dirty
air bubble
unfocused microscope
no cells in field of view
not switched on
what is the shape of a plant cell?
there are many different shapes of plant cell
Name some aseptic techniques you could use when doing a bacteria experiment
Sterilise equipment/surfaces
sterilise sugar
Secure lid w/ tape and only lift a little bit
Name some health conditions that might develop if a person eats a diet high in
saturated fat.
CVD/CHD
heart attack/disease
stroke
Uses of energy released in respiration
muscle contraction
keeping warm
active transport
building larger molecules