B2 Test

Question 1

What are the three uses of mitosis ?

Answer 1

Repair damaged tissues
Replace worn out cells
Enable organisms to increase in size

Question 2

What is osmosis?

Answer 2

Osmosis is a special type of diffusion. It is the movement of water molecules through a selectively permeable membrane.

Question 3

Is the following diffusion or active transport?

1) Oxygen moving from lungs into blood .
2) CO2 entering leaves of plants
3) absorbing glucose during digestion.

Answer 3

Oxygen moving from lungs into blood . - Diffusion

2) CO2 entering leaves of plants - Diffusion
3) absorbing glucose during digestion. - Active Transport

Question 4

Explain why the potato in pure water is longer?

Answer 4

Water has entered the potato by osmosis, this means there is a higher water potential in the solution compared to the potato . The length increases as there is higher pressure

Question 5

Describe how the structure of the vein is different from the structure of the capillaries.

Answer 5

The vein has a small lumen and the wall is made up of single layer cell.

The capillary has a large lumen, smooth lining and the outer wall is fairly thin.

Question 6

Describe the processes of osmosis and active transport.

Answer 6

Osmosis is the movement of water molecules through a selectively permeable membrane from a high to low concentration.
Active transport is the movement of this is also used across a membrane against a concentration gradient (from a low to high concentration.)
Active transport requires energy where is osmosis does not require energy as it is a passive motion. Active transport also makes use of carrier proteins in the cell membrane.

Question 7

Explain why small organisms do not need transport systems

Answer 7

They have a large surface area to volume ratio, all the nutrients and respiratory can be taken in by diffusion across the body surface,

Question 8

Suggest why cells need to differentiate?

Answer 8

The structures have been changed to adapt to perform a function.

Question 9

What is diffusion?

Answer 9

Net movement of particles from a high concentration to a low concentration.
Move down a concentration gradient.
The concentration of particles move until it is the same everywhere.

Question 10

Describe the difference between embryonic and adult stem cells?

Answer 10

Embryonic are found in embryos and adult cells are found in bone marrow, brain, etc.
Embryonic can differentiate into anything and adult stem cells can on,t differentiate into certain types .

Question 11

Write down the name given to cells before they become specialised.

Answer 11

Stem cells