Cell membranes

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  • Created by: Emma
  • Created on: 26-03-13 19:58
Nicotine has an effect on nerve cells, but nt on other types of the body. Explain why
Nicotine only binds to receptors with a complementary shap. Different cells have different membrane-bound receptors. Nicotine only affects nerve cells because they have the correct receptor for nicotine.
1 of 10
Beetroot contains a red pigment. In an experiment what temperature would contain the greatest concentration of beetroot pigment?
70 degrees C
2 of 10
Describe and explain the difference of beetroot at 10 - 30 degrees C
at 30 membrane is more permeable at high temperatures. The molecules in the membrane have more energy so can move more increasing permeability. Causes more pigments to move out of the cells into the water.
3 of 10
Describe and explain the differencee between the results at 30 - 50 degrees C
Higher concentration at 50 because the higher temperature was exposed to cause membranes to break down, increasing permeability and causing more pigment to move out of the cell and into water
4 of 10
If beetroot was put in a freezer for 10minutes, then left to thaw before absorbance reading was taken, wouldthe reading be high or low
High as at temperatures below 0, channel and carrier proteins would denature, ice crystals form which pierce membrane. Makes membrane highly permeable so a lot of pigment would leak out into solution
5 of 10
Pieces of potato of equal mass were put into different concentrations of sucrose solution for 3 days. Explain why 1% and 2% gained mass
Water potential of the sucrose was higher than in the potato. Water moves by osmosis from high to low concentration, so water moves into the potato increasing its mass
6 of 10
Suggest a reason why massof potato in 3% sucrose stayed the same
Water potential of the potato and the solution are the same
7 of 10
What would you expect the mass difference for a potato in a 5% sucrose solution and explain
-0.4g. The potato has a higher water potential than the solution, net movement of water is out of the potato. Difference in water potential between the potato and the solution is the same as 1% solution, mass should be about the same
8 of 10
Describe the role of membrane proteins in faciliated diffusion
Involves channel proteins. which transport charged molecules across the membrane, down their concentration gradient. Also involves carrier proteins, transport large molecules across the membrane, down their concentration gradient
9 of 10
Explain the difference between endocytosis and exocytosis
Endocytosis takes in substances from outside the cell, via vesicles formed from the plasma membrane. Exocytosis secretes substances from the cell, via vesicles made from the Golgi apparatus
10 of 10

Other cards in this set

Card 2

Front

Beetroot contains a red pigment. In an experiment what temperature would contain the greatest concentration of beetroot pigment?

Back

70 degrees C

Card 3

Front

Describe and explain the difference of beetroot at 10 - 30 degrees C

Back

Preview of the front of card 3

Card 4

Front

Describe and explain the differencee between the results at 30 - 50 degrees C

Back

Preview of the front of card 4

Card 5

Front

If beetroot was put in a freezer for 10minutes, then left to thaw before absorbance reading was taken, wouldthe reading be high or low

Back

Preview of the front of card 5
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