EXAM STYLED QUESTIONS (PAPER 1) Flashcards
answer exam styled questions
Explain why the potato pieces in the 0.4 mol/dm3 salt solution decreased in mass
- water moves out of cells / potato
- by osmosis
(because) the solution in the - cells / potato is less
concentrated than outside
or - (because) the solution in the
cells / potato is more dilute than
outside
contains genetic information
nucleus
mitochondria
aerobic respiration
Controls the movement of substances into and
out of the cell
cell membrane
What is the function of chloroplasts?
photosynthesis
Name one type of cell in a potato plant that does not contain chloroplasts
root hair cell
Why did the student dry the surface of each potato piece with a paper towel
in step 5?
STEP 5- 5. After 30 minutes, remove each potato piece and dry the surface with a paper towel
to make sure only the potato
mass was measured
or
if water / solution / liquid was left
on (the potato), the mass would
be higher / affected
Name one structure which is present in both plant cells and fungal cells
but not in animal cells.
- cell wall
- permanent vacuole
Which disease is caused by a fungus?
Rose black spot
A fungal cell divides once every 90 minutes.
How many times would this fungal cell divide in 24 hours?
24/1.5
=16
Where is protein digested in the human digestive system?
stomach
Which chemical could be used to test if the burgers contain protein?
biuret reagent
Iodine solution
is an irritant
what is the risk and plan to minimize risk
risk-May cause allergic
reaction or skin rash
plan to minimize risk-
wash skin immediately
(after contact)
or
wear gloves
or
clean up spills
Sharp knife
what is the risk and plan to minimize it
risk- may cut you /
someone / skin
plan to minimize risk- cut away from the body
or
cut on a chopping board
or
keep fingers away from blade whilst cutting
Give a reason for each of the following steps in the method.
A thin layer of onion epidermis is used
thin layer
(to) help see individual cells
Give a reason for each of the following steps in the method.
Iodine solution is added to the onion epidermis.
iodine solution
(to) stain / see the parts of the
cell
Give a reason for each of the following steps in the method.
The cover slip is lowered onto the onion epidermis at an angle
at an angle
(to) prevent / reduce air bubbles
Figure 3 shows what the student saw under the microscope at a magnification
of ×400.
The length of cell Z in Figure 3 is 4.8 cm.
Calculate the real length of cell Z.
Give your answer in micrometres (µm
recall of equation
magnification =
size of image/size of real object
rearrangement of equation
size of real object =
size of image/magnification
substitution
4.8/400
=0.012 (cm)
conversion
=120 (µm)
Onion cells can be seen using an electron microscope.
Give two ways onion cells would look different when seen using an electron
microscope.
any two from:
* include magnification / scale
* use continuous lines
or ensure no gaps in lines
* do not draw overlapping cells
* draw (wider) cell walls
* do not shade
* draw all the cells present
* draw correct cell shapes
* do not have gaps between
cells
* draw nuclei in correct location
* label cell part(s)
Hornets are insects that sting other animals and cause pain.
Hornet moths do not sting other animals.
Suggest how mimicry helps the hornet moth survive
(it looks like the hornet so)
predators / animals are tricked /
deceived (by the colouring) and
so avoid eating it
Adult hornet moths lay eggs box that hatch into larvae.
The larvae of the hornet moth:
* live inside the roots of trees
* use the tree roots as a source of food
* cause damage to the tree roots.
Explain why a tree might die if the roots of the tree are damaged.
- less absorption of water
o less water so lower rate of photosynthesis
o so less glucose produced
o for respiration / energy release
o so less cellulose produced so fewer cells walls /
cells made
o so fewer amino acids produced to make new
proteins
o cells lose turgidity - less absorption of (named) ions / minerals
o fewer nitrates so fewer proteins made for growth
o fewer magnesium ions so less chlorophyll produced
o so lower rate of photosynthesis - damage to phloem
o less transport of sugars to root cells
o for respiration / energy release - damage to xylem
o less water transported (to cells)
o fewer nitrates reach cells
o so fewer proteins made for growth
o fewer magnesium ions reach cells
o so less chlorophyll produced
o less magnesium / chlorophyll so lower rate of
photosynthesis
The larvae of the hornet moth form when fertilised eggs divide by mitosis.
Describe how mitosis produces two genetically identical cells.
genetic material / DNA /
chromosomes is doubled /
replicated / copied / duplicated
the (replicated) chromosomes
are pulled / moved apart
cytoplasm divides into two
(cells)
or
cell membrane divides to form
two cells
the set of chromosomes in each
new cell are identical (to one
another)
The cells which are first formed from the fertilised eggs of the hornet moth are
stem cells.
Name the process by which these stem cells then form specialised cells.
differentiation
Water and carbon dioxide are exchanged between leaves and the atmosphere through pores called stomata.
Name the cells that control the opening and closing of the stomata
guard (cells)
Water moves through a plant in the transpiration stream.
Describe two differences between the transpiration stream and translocation.
any two from:
* transpiration (stream)
involves xylem and
translocation involves
phloem
* transpiration (stream)
transports water (and
minerals / ions) and
translocation transports
(dissolved) sugars
* transpiration (stream)
moves substances upwards
and translocation moves
substances upwards and
downwards
Which environmental conditions would cause the rate of transpiration to be greatest in a plant?
warm with low humidity
The changes in the mean width of the stomata in normal conditions are
an advantage to the plant.
Explain how
stomata (almost) closed at
(mid)night because there is no /
less light for photosynthesis
(closing stomata) reduces /
prevents water loss
stomata open wide(st) at midday
as maximum light intensity for
photosynthesis
(stomata open wide) to take in
most / more carbon dioxide for
photosynthesis
The changes in the mean width of the stomata in low atmospheric carbon dioxide
are different from the changes in normal conditions.
Explain how the difference helps the plant to survive in low atmospheric
carbon dioxide.
stomata are open wider and for
more time
(so allows plant) to take in more
carbon dioxide for
photosynthesis
Describe how the alveoli and the villi are adapted to increase absorption.
- both have a large surface area
o to maximise diffusion - both have thin walls or have walls that are one cell thick
o to reduce diffusion distance / time - both are in close proximity to blood supply
o to reduce diffusion distance / time - both have a good blood supply or both have a capillary network
o to maintain concentration gradient - villi have microvilli
o to (further) increase surface area - cells of villi contain many mitochondria
o for active transport
Give one way HIV can spread from one person to another person.
- sexual contact / intercourse
- exchange of body fluids
Explain how a vaccine for HIV could work to prevent a person developing
HIV infection.
inactive HIV / virus is injected
(into bloodstream / muscle /
body)
white bloods cells produce
antibodies (against inactive
virus)
(if infected with HIV) correct /
specific antibodies are produced
quickly
antibodies destroy the (active)
virus / HIV
A person with late stage HIV infection has AIDS.
Scientists have produced monoclonal antibodies for HIV.
The monoclonal antibodies can prevent a person infected with HIV developing AIDS.
Describe how the monoclonal antibody for HIV can be produced
HIV / antigen / protein injected
into mouse
extract / collect (mouse)
lymphocytes that make a
specific antibody to HIV /
antigen / protein
lymphocytes are combined with
a tumour cell to create a
hybridoma
(hybridoma) cloned to create
many cells that produce the
antibody
Suggest how the monoclonal antibody for HIV helps to prevent a person infected with
HIV developing AIDS
monoclonal antibody is
complementary / specific to HIV
antigen
monoclonal antibodies attach to
(all the) HIV antigens
(so) HIV cannot bind to (human)
cell
or
(so) HIV genetic material cannot
enter (human) cell
