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Flashcards in Hard questions Deck (14)
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1
Q

Describe why facilitated diffusion requires no metabolic energy

A
  1. Particles have their own kinetic energy

2. Move down the concentration gradient

2
Q

Explain why glucose cannot pass through a cell membrane by simple diffusion

A
  1. Phospholipids act as a barrier

2. The molecules are too large

3
Q

Suggest how the leaf of pondweed is supported

A
  1. Air spaces give buoyancy

2. Supported by surrounding water

4
Q

Suggest why antibodies specific to nuclear proteins are not normally made

A
  1. Nuclear proteins normally hidden in the nucleus
5
Q

Suggest how water is being lost from the cut stem when leaves have been treated with petroleum jelly in a potometer experiment

A
  1. Evaporation form upper leaf surfaces
6
Q

Suggest two sources of error in a potometer experiment

A
  1. Not all lower leaf surfaces covered
  2. leaks in apparatus
  3. Shoot not cut under water
  4. Error in reading position of the meniscus
7
Q

Explain why bone is described as a tissue and gills are described as organs

A
  1. Tissue has few types of cells and performs one function
  2. Bone has a few types of cells and performs one function
  3. Organs consist of several tissues
  4. Gills contain blood, bones, epithelial and connective tissue
8
Q

How would the calculated rate differ form the true initial rate of reaction in an enzyme reaction

A
  1. Initial rate is likely to be greater

2. Because higher concentration of substrate at start, so more chance of substrate entering the active site

9
Q

Give ways to refine an experiment so reproducible results would be obtained

A
  1. Specify volumes of reactants added
  2. Specify volume that should be removed for testing
  3. Stir before taking the sample
  4. Test with iodine- for starch, or other chemicals
  5. Carry them all out at the same temperature
10
Q

Explain why vaccinations are examples of active immunity

A
  1. Antibodies are produced
  2. Activation of lymphocytes
  3. Memory cells remain
11
Q

State 3 properties of fibrous proteins that are different to globular proteins

A
  1. Insoluble
  2. Strong
  3. Unreactive
12
Q

How could haemoglobin be identified in urine

A
  1. Add biurets reagent
  2. Colour change from blue to purple
  3. Compare with control
13
Q

Outline how the difference in lumen size between arteries and veins is related to their function

A
  1. In arteries small lumen maintains high pressure
  2. In veins large lumen- low resistance needed because of low pressure
  3. Same flow rate is achieved by having a larger volume
14
Q

Why is movement of molecules from the plasma membrane towards the centre of living cells greater than in an experiment

A
  1. Involvement of vesicles/ cytoskeleton