Transport in Cells

Question 1

What is diffusion?

Answer 1

The spreading out of particles from an area of higher concentration to an area of lower concentration

Question 2

What factors affect the rate of diffusion?

Answer 2

• The bigger the concentration gradient the faster the rate of diffusion
• The higher the temperature the faster the rate of diffusion

Question 3

What can fit through a cell membrane?

Answer 3

Small molecules such as oxygen, glucose, amino acids, and water

Question 4

What effect does surface area of a membrane have on the rate of diffusion across it?

Answer 4

the larger the surface area, the faster the rate of diffusion

Question 5

What is osmosis? `

Answer 5

The movement of water particles across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration

Question 6

What will happen to a sucrose solution during osmosis? `

Answer 6

It will become more dilute

Question 7

What is passive diffusion?

Answer 7

Diffusion that acts with the concentration gradient and therefore requires no energy

Question 8

How to study the effect of different sugar solutions on plant tissue?

Answer 8

• cut a potato into cylinders and weigh each one
• place each one into a beaker containing a different concentration of sucrose, one being pure water
• leave for 24 hours
• dry them with a paper towel and weigh again
• increase in mass = drawn in water via osmosis
• decrease decrease in mass = water drawn out via osmosis
• keep volume, temperature, time, and type of sugar the same

Question 9

What is active transport?

Answer 9

Diffusion that requires energy because it acts against the concentration gradient (lower concentration to higher concentration)

Question 10

How do root hair cells take in mineral ions?

Answer 10

• concentration of mineral ions is higher in the root hair than the soil
• the plant uses energy from respiration to extract them

Question 11

Wen do humans use active transport?

Answer 11

in the gut when taking in nutrients from the blood

Question 12

What does a surface area to volume ratio show?

Answer 12

How east it is for an organism to exchange substances with its environment

Question 13

How are exchange surfaces well adapted for diffusion?

Answer 13

• thin membrane
• large surface area
• lots of blood vessels
• well ventilated
• moist
• warm