Nat5 Biology Unit One Cell Biollogy Key Area 2 Transport across cell membranes

Question 1

What does concentration gradient mean?

Answer 1

The difference in concentration that exists between a region of high concentration and a region of low concentration

Question 2

What is diffusion?

Answer 2

The movement of molecules from a region of high concentration to a region of low concentration

Question 3

What is the cell membrane made of?

Answer 3

Proteins and phospholipids and it is selectively permeable

Question 4

What does selectively permeable mean?

Answer 4

Something that only allows molecules of a certain size to pass through it while others can’t

Question 5

What is passive transport?

Answer 5

The movement of molecules down a concentration gradient

High concentration—————->Low concentration

Passive transport does not require energy input

Question 6

What type of transport is diffusion?

Answer 6

Passive transport- it doesn’t need any energy input

High————>low

Question 7

Examples of diffusion

Answer 7

Oxygen moving from an alveolus into a blood capillary in the lung

A plant leaf taking up carbon dioxide from the internal air space for photosynthesis

Question 8

What is osmosis?

Answer 8

The movement of water from an area of higher water concentration to an area of lower water concentration through a selectively permeable membrane

Question 9

What structure in any cell is selectively permeable?

Answer 9

A sap vacuole or a cell membrane

Question 10

How do you calculate percentage change?

Answer 10

Change
————————-x100
Original

Question 11

Word equation for aerobic respiration

Answer 11

Glucose+Oxygen=ENERGY+water+carbon dioxide

Question 12

What type of cells do the terms turgid and plasmolyse app lay to?

Answer 12

Plant cells

Question 13

What does it mean if a cell (always plant) has gone turgid?

Answer 13

There was a higher water concentration outside the cell, so the water went into the cell through the selectively permeable membrane and osmosis so it expanded against the cell wall

Question 14

What does it mean if a cell (always plant) goes plasmolysed

Answer 14

There was a higher water concentration inside the cell, so through osmosis and a selectively permeable membrane, the water inside the cell went out, and the membrane came away from the cell wall

Question 15

What happens to animal cells instead of getting turgid or plasmolysed?

Answer 15

They burst if they gain too much water (because they don’t have a cell wall to protect them and they shrink if they lose too much

Question 16

What is active transport?

Answer 16

Movement against a concentration gradient

Low concentration————-> High concentration

Active transport does require energy input

Question 17

What do membrane proteins act as?

Answer 17

Specific carriers of ions or molecules during active transport

Question 18

What do cells that use active transport have a large number of?

Answer 18

They have loads of mitochondria because they need energy

Question 19

What does ATP do?

Answer 19

Supplies the energy needed for active transport, muscle cell contraction, nerve impulse transmissions, cell division and protein sysntheis