Transport across a cell membrane 2

Question 1

What is the cell membrane made of

Answer 1

Phospholipids and proteins

Question 2

How can the membrane be described as and why

Answer 2

Fluid because the phospholipids are constantly moving

Question 3

4 examples of what the function of a protein on a cell membrane

Answer 3

• Form channels which can allow molecules that are small enough to travel through
• Receptors
• Enzymes
• Carrier proteins for active transport

Question 4

What word describes the cell membranes function

Answer 4

Selectively permeable, this means that some molecules can pass from one side to another while others cant

Question 5

What is passive transport and does it need energy

Answer 5

Passive transport does not require energy instead it relies on the fact substances are found in different concentrations in different places . Substances always move from a higher to lower region of concentration; down a concentration gradient

Question 6

What is diffusion

Answer 6

Diffusion is the movement of molecules or ions from a region of high concentration to low concentration

Question 7

When does diffusion stop

Answer 7

When the concentration of the substance is even throughout

Question 8

What does diffusion allow

Answer 8

Diffusion allows substances to move within a cell as well as allowing material to enter and leave

Question 9

What is osmosis

Answer 9

Osmosis is the movement of water molecules from a region of high to low water concentration through a selectively permeable membrane

Question 10

What molecules move by osmosis

Answer 10

Water

Question 11

What is active transport

Answer 11

Active transport is the movement of molecules against a concentration gradient

Question 12

How do the molecules move in active transport

Answer 12

Molecules are moved by carrier proteins which requires energy provided by ATP

Question 13

What happens when a plant or animal cell is placed in solution of equal concentration in the cell and surrounding solution

Answer 13

The cell will remained unchanged

Question 14

What happens when the surrounding solution of the plant cell has a greater water concentration than in the vacuole

Answer 14

The cell will become swollen. This is defined as turgid

Question 15

What happens if the solution surrounding of the plant cell has a lower water concentration than in the cell

Answer 15

The water will leave the cell. This is defined as plasmolysed

Question 16

What happens when the surrounding solution of the animal cell is greater than in the cell

Answer 16

The cell will burst as there is no cell wall

Question 17

What happens if the surrounding solution has a loer water concentration than in the cell

Answer 17

Water will pass out the cell causing it to shrivel and shrink