Review Questions Flashcards
(15 cards)
Is diffusion fastest in liquids or in gases?
gases
Is diffusion fastest at high or low temperatures?
high
Is diffusion fastest if the concentration gradient is higher or if it is lower?
higher
- LIPIDS (FATS) / PROTEINS.
LIPIDS (FATS) / PROTEINS
- # 1 is true
Cross out one of the words in pairs to make the sentences correct.
Some substances can pass though all membranes because all cell membranes are made of very similar LIPIDS (FATS) / PROTEINS. The differences in the permeability properties of membranes are due to the different LIPIDS (FATS) / PROTEINS they possess.
1 There is no net movement of oxygen through the membrane.
If the concentration of oxygen on either side of a cell membrane is equal which statement(s) is/are true?
Circle your answers.
Which methods use protein carriers?
simple diffusion facilitated diffusion active transport exocytosis pinocytosis phagocytosis
Which methods require the cell to supply energy (ATP)?
simple diffusion facilitated diffusion active transport exocytosis pinocytosis phagocytosis
In which methods do materials actually pass through the membrane and can be moved up a concentration gradient?
simple diffusion facilitated diffusion active transport exocytosis pinocytosis phagocytosis
Which methods only move things into cells (never out of cells)?
simple diffusion facilitated diffusion active transport exocytosis pinocytosis phagocytosis
pinocytosis, phagocytosis
Which methods could be used to move ions through cell membranes?
simple diffusion facilitated diffusion active transport exocytosis pinocytosis phagocytosis
facilitated diffusion active transport
By which method do small fat-soluble molecules cross cell membranes?
simple diffusion facilitated diffusion active transport exocytosis pinocytosis phagocytosis
simple diffusion
An animal cell is placed in a large volume of a solution. It starts to swell up as water enters the cell.
a) By what process does water enter the cell?
b) What does that tell you about the solution?
c) What will happen to the cell?
d) Would the same thing happen to a plant cell placed in the same solution?
a) Osmosis
b) It is hypotonic (lower solute conc than the cell)
c) It will burst
d) You can’t be sure. It depends on whether the plant cell is flaccid or turgid and on its solute concentration. If the solution was also hypotonic compared to the plant cell it might take in water, but it would not burst as it has a cell wall.
A plasmolysed plant cell is in equilibrium (no net entry or exit of water) with an external solution.
a) What does this tell you about the cytoplasm and the external solution?
b) Could you make the same statement about a turgid plant cell in equilibrium with an external solution?
a) They are isotonic.
b) No, the solution would be hypotonic compared to the cytoplasm.
Why is it important that plant leaf cells remain turgid?
Turgidity allows the leaf to support itself in the best position to obtain sunlight. If the leaf cells became flaccid the leaf would wilt and it would capture less light.
Why do freshwater protozoa need contractile vacuole
They live in hypotonic surroundings, so they continually gain water by osmosis and so are in danger of swelling and bursting if they cannot pump out water.
