BIOLOHY 2020 Flashcards
Name two types of microorganism that cause decay
bacteria
fungi
Give two control variables the student should have used in this investigation.
- volume of milk
- exposure to air / oxygen
The time taken for cows’ milk to reach pH 5 at 10 °C is less than the time taken for
cows’ milk to reach pH 5 at 5 °C.
Suggest one reason why.
any one from:
* bacteria / microbes /
microorganisms / fungi
dividing faster (when warmer)
* reactions (in the bacteria) are
happening faster (to decay
milk)
* (because there is) more
(kinetic) energy
* enzyme activity is higher (at
10 °C than at 5 °C
Suggest two reasons why the different types of milk took different lengths of time to
reach pH 5
- different concentration / type
of fat / lipid - different starting pH
Suggest one reason why some people are concerned about the use of golden rice
gene may contaminate / enter
other breeds / species
* reduction / extinction of
population of wild / traditional
rice
* reduction / extinction of
population of flowers / insects
* high cost of seeds
* may have too much vitamin A
(in diet
Farmers can spray seeds with gibberellins to start germination.
What are two other uses of gibberellins?
to increase fruit size
to promote flower production
Suggest how the students measured the length of the curved seedling in Figure 4
- measure with a flexible ruler
or a tape measure
Describe two improvements the students should make to their investigation.
use equal numbers of
seedlings (in each dish)
* use seedlings of the same
(initial) height
why is dna a polymer
many (joined) nucleotides or
monomers
Some parts of DNA do not code for proteins.
Describe how non-coding parts of DNA can affect the expression of genes.
(non-coding parts) can switch
genes on / off
Give the genotype of person 1.
Explain your answer
Dd / dD
has D because has Dupuytren’s
and has d because child /
person 6 is homozygous
recessive or does not have
Dupuytren’s or is dd
In most MRI scanners the person being scanned needs to stay completely still.
A functional MRI (fMRI) scanner allows a person to move while the scanner makes
images of the person’s brain activity.
Suggest how the fMRI scanner could help to find out more about the brain damage a
person has
any three from:
* can ask people to do different
tasks (while taking scan)
* to see which part of brain is
active / inactive
* to compare with a person
without brain damage
* to see (exactly) where the
damage is
Describe how the brain receives information about light entering the eye.
You should include the names of structures in your answer.
(cells in) retina sensitive to light
impulse passes along (sensory)
neurone
(along) optic nerve
The eyes of some birds contain cells that detect ultraviolet (UV) light.
UV light is reflected by some fruits and the urine of small mammals.
Explain how birds that detect UV light have evolved from birds that could not detect
UV light.
- mutation (in gene / DNA)
- randomly or due to chance
- causes new / different protein / (visual) pigment to be made
- in the retina of bird
- (so more) variation in the wavelengths of light birds retinas could
detect - birds with the mutation or birds able to detect UV are more likely
to see fruits (that reflect UV) - birds with the mutation or birds able to detect UV are more likely
to see where small mammals are or have been - therefore get more food (small mammals or fruit)
- avoid being eaten (by small mammals)
- out competing those birds without the mutation or birds not able
to detect UV - so more likely to survive and reproduce or have offspring
- by natural selection
- passing on allele / gene / mutation to offspring
- repeated over many generations
Describe two reasons why the biomass of the insects eaten by dogs does not all
become biomass of the dogs.
carbon dioxide from
respiration (from dog)
* urea from excretion (from
dog
Explain how making dog food from insects could improve human food security in
the future.
more space for crops (for
humans)
less methane (from animals)
therefore less global warming
(therefore) less harmful effects
of global warming on (human)
food production
The oldest fossils of human ancestors found in this area are 700 000 years old.
Andrewsarchus was a carnivore and Brontotherium was a herbivore.
Suggest how the extinction of Andrewsarchus could have resulted in the extinction
of Brontotherium.
extinction of Andrewsarchus)
led to population increase /
evolution of another predator
because Andrewsarchus no
longer competing for food /
resources
other predator (population)
hunted more Brontotherium
Give three reasons why the fossil record is not clear for older species
- fossils buried deep(er) so
hard(er) to find - fossils smaller so harder to
find - more likely to be destroyed by
geological activity /
earthquakes / erosion - oldest organisms were softbodied so most of the tissue
decayed
Give one disadvantage and one advantage of mass extinction events.
Answer in terms of evolution.
(disadvantage)
any one from:
* loss of potential, future
biodiversity
* reduction in range of alleles
(advantage)
allows evolution of new species
/ varietie
