2019 Biology Paper 1 Flashcards
Which of the following 3 plant hormones are involved in leaf abscission?
* auxin
* ethene
* gibberellin
auxin and ethene
What makes a compound a hormone?
- Hormones are chemical messengers.
- Hormones are produced in one part of an organism, but have effects in another part.
- Hormones affect the activity of target cells.
- Hormones are long-lasting
- Hormones have a wide-spread effect.
State the roles of gibberellin, other than causing an increase in internodal length.
- seed germination
- flowering in long-day plants
- cellular transcription / translation
- prevention of leaf abscission
- aiding in stomatal opening
- promotion of fruit development
- promotion of activity of amylase / hydrolysis of starch
What colour is seen from a positive Biuret test? (protein is present)
Purple
What colour is seen from a negative biuret test? (protein is not present)
Blue
What colour is seen from a negative iodine test? (starch is not present)
Brown / Yellow
What colour is seen from a positive iodine test? (Starch is present)
Blue / Purple
What is a conjugated protein?
- has a non-protein group
- has a prosthetic group
- prosthetic group attached by covalent bonds / ionic interactions / hydrogen bonds
What hormone regulates metabolism?
Cortisol
State the functions of adrenaline.
- increases heart rate
- increases blood glucose content
- increases blood flow to muscles
- increases glucogenolysis
- causes pupils to dilate
- decreases blood flow to gut
- increases blood pressure
- dilates bronchioles
- increases air flow to alveoli
- increases breathing rate
Why is the ‘dark reaction’ a suitable name for the light-independent reaction?
Light energy is not needed for this stage to occur.
Stems planted in different concentrations of auxin showed fewer side shoots with increased auxin concentration. Why?
Auxin causes apical dominance.
State the commercial uses of auxin.
- rooting powder
- micropropagation
- weed killers / herbicides
- production of seedless fruit
- prevention of abscission
- promotion of fruit ripening