Osmosis, Diffusion etc

Question 1

Diffusion

Answer 1

Molecules moving from high to low concentration. No energy needed. Molecules diffuse till they’re evenly spread apart.

Question 2

Diffusion by digestion

Answer 2

The wall of the small intestine is made up of villi, which is very thin and increase the surface area of the intestine, which increases the speed of diffusion. Dissolved food molecules move from the intestine into the blood stream.

Question 3

Osmosis

Answer 3

Diffusion of water from high concentration to low concentration through partially permeable.

Question 4

Dilute solution

Answer 4

High concentration of water molecules

Question 5

Concentrated solution

Answer 5

Low concentration of water molecules

Question 6

Medium water concentration in plants

Answer 6

Strong cell wall providing support and protection, cytoplasm at the same concentration as the water surrounding the cell, no net movement

Question 7

Low water concentration in plants

Answer 7

Water has left the cell because the water surrounding the cell is less concentrated than the cytoplasm in the cell, cytoplasm is plasmolysed

Question 8

High water concentration in plants

Answer 8

A lot of water in the cell because the water outside is more concentrated than inside the cell, cytoplasm pushing against the cell wall, the cell is turgid

Question 9

Plasmolysed cell

Answer 9

Cytoplasm is pulled away from the cell wall

Question 10

Medium water concentration in blood cell

Answer 10

The cell cytoplasm is at the same concentration as the water surrounding the cell

Question 11

Low water concentration in blood cell

Answer 11

Water has left the cell because the water concentration outside the cell is less than the concentration in the cell. The cell becomes crenated as the cytoplasm pulls away from the cell membrane

Question 12

High water concentration in blood cell

Answer 12

Water has entered the cell pushing the new cytoplasm against the cell membrane. Because the cell has no cell wall, it bursts as it becomes turgrid. Cell destroyed.

Question 13

Active transport

Answer 13

Protein carried in the cell membrane ‘pick up’ particles and move them against the concentration gradient.

Question 14

Diffusion in gills

Answer 14

Gas exchange occurs in the gills. Gills have a large surface area. As water moves over the gills, oxygen diffuses from the water into the blood. At the same time, carbon dioxide diffuses in the opposite direction

Question 15

Diffusion in photosynthesis

Answer 15

Oxygen is produced as a waste product of photosynthesis. CO2 and Oxygen both move in and out of the plant by diffusion through pores on the leaf surface called stomata. CO2 diffuses into the leaf, where it fills air spaces and comes into contact with lots of leaf cells. CO2 diffuses into the cells to be used by chloroplasts for photosynthesis.

Question 16

Diffusion in enzymes

Answer 16

Only small molecules are able to move across exchange surfaces by diffusion. Large food molecules such as carbohydrates, proteins and fats are too big to move through all membranes. They must be broken down by digestive enzymes.

Question 17

Diffusion in roots

Answer 17

Roots are adapted for transporting water, minerals and nutrients from the soil and into the plant. Roots are covered in a layer of specialised cells called root hair cells. The structure of a root hair cell enables efficient exchange.