Transport Across Membrane

Question 1

Describe the structure of the cell membrane?

Answer 1

The cell membrane is selectively permeable is it will let smaller soluble molecules pass through but don’t let through larger insoluble ones

Question 2

State what is meant by selectively permeable and concentration gradient?

Answer 2

Selectively permeable means that it only allows some substances to pass through not all and concentration gradient means that the particles moves from high to low concentration in passive transport

Question 3

Which substances move out of and into cells in diffusion?

Answer 3

Glucose and oxygen diffuse into the cells from a high concentration in the bloodstream to the low concentration in cells. Carbon dioxide produced by respiration diffuses out of the cells into the blood where it is then exhaled via the lungs

Question 4

What is the importance of diffusion?

Answer 4

The importance of diffusion is that it is vital for useful substances to enter the cell and wasteful substance to leave the cell

Question 5

What is the osmotic effect in both animal and plant cells?

Answer 5

In animal cells if the water concentration is low then the water molecules exit and the cells shrink but if the water concentration in animal cells are high then the cells swell up and burst. If it’s equal on both inside and outside the cell there’s no overall movement. In plant cells if the water concentration is low then the water molecules exit the cells and the cell contents shrinks away from the cell wall and vacuole shrinks. This is being known as plasmolysed. If the water concentration is high in plant then the cells swell and push against its contents. This is being known as Turgid.

Question 6

What is active transport?

Answer 6

Active transport is the energy requirements for protein molecules to move molecules and ions against the concentration gradient from a region of low to high concentration