BIOLOGY 2019 Flashcards
A concentration of 5.0 mg/dm3 of fertiliser caused a large increase in the population
of Daphnia.
Explain why
increased (growth /
reproduction of) algae
(more algae so) more food for
Daphnia
Scientists have now studied the whole human genome.
Give two benefits of understanding the human genome.
- diagnosis of inherited /
genetic disorder - gene therapy or treatment
of inherited disorders - understanding (human)
evolution
or
understanding ethnic
origins (of a person)
or
understanding ancestry - tracing human migration
pattern
Plan an investigation to show the effect of light from one direction on the growth of
plant seedlings
- several seedlings in each batch
or one pot of seedlings in each batch - measure heights of shoots
- leave some in dark with light from one side / direction in box with
hole - control(s) with all-round light or rotating on clinostat or in dark
- control variable(s) eg same temperature / water / soil type
- after suitable time (at least several hours)
- record appearance of seedlings re. light direction
- re-measure heights of shoots
- detail of how bent shoots were measured – eg use thread or
straighten them out - calculate mean height increase for each group
- use ruler / protractor to estimate angle of bending
Explain how phototropism in a plant shoot helps the plant to survive
leaves / plant receive(s) /
absorb(s) more light
(so) more photosynthesis
(so plant) produces more
glucose- MUST SAY MORE
Explain how the person’s eye could adjust to form a clear image of a nearer object.
ciliary muscles contract
(so ciliary muscles have a)
smaller diameter
(so) suspensory ligaments
loosen / slacken
(so) lens thickens or lens
becomes more curved /
rounded
(thicker) lens is more
convergent
light rays / image focused on
retin
Explain why a long-sighted person has difficulty seeing near objects clearly.
eye(-ball) is (too) short or lens
cannot be thickened enough
(so) light ‘focuses’ behind retina
Long-sightedness can be corrected by wearing spectacles.
Describe how spectacle lenses can correct long-sightedness.
convex / converging lens
light rays bent / refracted
(inwards) more
light rays focused on retina
Give a reason for each of the following steps shown in Figure 7.
Several groups of cells are scraped off the leaf:
Nutrients are added to the agar jelly:
Hormones are added to the agar jelly:
The plant cells are kept in sterile conditions:
The plant cells are kept at 20 o
C
(several groups)
so many / several plants can be
produced
(nutrients)
for making protein / amino acids
or for making chlorophyll
or for providing energy or for
respiration
(add hormones)
so differentiation occurs
or so roots / shoots develop
(sterile conditions)
to prevent growth / entry of
microorganisms / named type
or prevent decay / disease
(temperature = 20 o
C)
so optimum / good growth
Explain why the method shown in Figure 7 produces only pink-flowered plants.
(all new plants have been)
produced by asexual
reproduction / mitosis or
produced without (fusion of)
gametes
(so) all are genetically identical /
clones
or all are CR
CW / heterozygous
Explain how the gland you named in Question 06.1 and the kidneys reduce
water loss
pituitary gland detects increased blood concentration and lower water potential, s (more) ADH / hormone
release
(and hormone / ADH causes)
increased permeability of kidney
tubules (to water)
(so) increased water
reabsorption
Explain two biological reasons why most doctors think that a kidney transplant is a
better method of treatment than dialysis.
dialysis requires anti-clotting drugs and so may lose
more blood if cut
not poisoned by urea
less / no chance of causing
damage to body cells / tissues
Why did the rate of reproduction increase between 2 hours and 7 hours?
more bacteria so more divisions /
reproduction (per unit time)
After 12 hours, the rate of reproduction decreased.
Suggest three ways the scientists could maintain a high rate of reproduction in the
bacterial culture.
any three from:
* add (more) sugar
* add (more) amino acids /
protein
* add (more) oxygen
* increase temperature
* remove toxins / waste
or maintain pH
* stir the culture
Explain the advantage of making crop plants resistant to glyphosate.
can use the glyphosate / weed
killer to kill weeds but not kill /
affect crop
(so) less competition for light /
water / minerals / ions
(so) crops have high(er) yield
A person with Type 2 diabetes often has a higher blood insulin concentration than a
non-diabetic person.
Explain why
cells / liver / muscles absorb
less glucose
(so) glucose concentration in
blood remains high
(high blood glucose stimulates /
causes) pancreas to release
more insulin
