2019 Biology Paper 1 Flashcards

1
Q

Which of the following 3 plant hormones are involved in leaf abscission?
* auxin
* ethene
* gibberellin

A

auxin and ethene

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2
Q

What makes a compound a hormone?

A
  • 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.
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3
Q

State the roles of gibberellin, other than causing an increase in internodal length.

A
  • 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
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4
Q

What colour is seen from a positive Biuret test? (protein is present)

A

Purple

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5
Q

What colour is seen from a negative biuret test? (protein is not present)

A

Blue

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6
Q

What colour is seen from a negative iodine test? (starch is not present)

A

Brown / Yellow

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7
Q

What colour is seen from a positive iodine test? (Starch is present)

A

Blue / Purple

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8
Q

What is a conjugated protein?

A
  • has a non-protein group
  • has a prosthetic group
  • prosthetic group attached by covalent bonds / ionic interactions / hydrogen bonds
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9
Q

What hormone regulates metabolism?

A

Cortisol

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10
Q

State the functions of adrenaline.

A
  • 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
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11
Q

Why is the ‘dark reaction’ a suitable name for the light-independent reaction?

A

Light energy is not needed for this stage to occur.

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12
Q

Stems planted in different concentrations of auxin showed fewer side shoots with increased auxin concentration. Why?

A

Auxin causes apical dominance.

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13
Q

State the commercial uses of auxin.

A
  • rooting powder
  • micropropagation
  • weed killers / herbicides
  • production of seedless fruit
  • prevention of abscission
  • promotion of fruit ripening
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