Transport systems

Question 1

Why do multicellular organisms need a transport system?

Answer 1

In a complex multicellular organism, a transport system is needed to carry materials from one part to another, as cells are located deep in the body.

Question 2

What are the four components of blood?

Answer 2

Plasma, white blood cells(lymphocyte, phagocyte) and red blood cells and platelets.

Question 3

What is the function of plasma?

Answer 3

Transports water and dissolved substances such as end products of digestion and waste materials to different parts of the body.

Question 4

What is the function of lymphocyte?

Answer 4

produce antibodies in response to foreign particles.

Question 5

What is the function of phagocyte?

Answer 5

Engulf and digest foreign particles through a process known as phagocytosis.

Question 6

What is the function of platelets?

Answer 6

initiates the process of blood clotting. Clot seals the wound to prevent excessive bleeding.

Question 7

What is the function of red blood cell?

Answer 7

transport oxygen form the lungs to all parts of the body.

Question 8

What are the characteristics of red blood cells?

Answer 8

Contains haemoglobin, absence of nucleus, and biconcave shape

Question 9

Explain how containing haemoglobin helps red blood cells carry out their function?

Answer 9

haemoglobin is a specialised protein which binds to oxygen at the lungs and transports it to the rest of the body.

Question 10

Explain how having an absence of nucleus helps red blood cells carry out their function?

Answer 10

more haemoglobin can be packed within each red blood cell, allowing the red blood cells to transport more oxygen.

Question 11

Explain how having a biconcave shape helps red blood cells to carry out their function?

Answer 11

increases surface area to volume ratio to increase the rate of movement of oxygen moving in and out of the cell by diffusion.

Question 12

What are the three blood vessels?

Answer 12

Arteries, veins and capillaries

Question 13

What is the function of arteries?

Answer 13

Usually transport blood rich in oxygen and nutrients away from the heart to the rest of the body.

Question 14

What is the function of veins?

Answer 14

Usually transport blood rich in carbon dioxide and waste substances towards thee heart away from the rest of the body.

Question 15

What is the function of capillaries?

Answer 15

Diffusion of substances occur across the capillary walls and it is the site of exchange of substances.

Question 16

What is the reason for the structure of arteries?

Answer 16

Arteries have thick, muscular and elastic walls to withstand high pressure of blood pumped from the heart

Question 17

What is the reason for the structure of veins?

Answer 17

Thin, less muscular and elastic walls. Low pressure of blood transported from the rest of the body to the heart.

Question 18

What is the reason for the structure of capillaries?

Answer 18

Very thin walls made of a single layer of cells. Allows movement of substances across walls.

Question 19

What is the function of xylem?

Answer 19

Xylem transports water and dissolved mineral salts from the roots to all parts of the plant in an upward direction.

Question 20

What is the function of phloem?

Answer 20

Transports sugar from the leaves to al parts of plant in both an upward and downward direction.

Question 21

Why are nutrients accumulated at the region where the bark was ringed?

Answer 21

Phloem is removed and thus sugars made in the leaves during photosynthesis cannot be transported downwards. Instead, sugar is accumulated at thee region just above the ring.

Question 22

Define diffusion.

Answer 22

Diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration.

Question 23

Why are glucose molecules able to pass through the partially permeable membrane?

Answer 23

Glucose molecules are small enough to diffuse through the partially permeable membrane. Starch molecules are too big to diffuse across the partially permeable membrane.

Question 24

Describe absorption of nutrients at small intestine.

Answer 24

After a meal, there is a higher concentration of digested food molecules in the small intestine than the bloodstream . The digested molecules diffuse across the intestinal cells into the bloodstream . The blood then transports these digested food molecules to other parts of the body.

Question 25

Describe the absorption of mineral salts at the root hair cells.

Answer 25

If there is a higher concentration of dissolved mineral salts in the soil than the root hair cells, the dissolved mineral salts will diffuse from the soil, through the root cells. The mineral salts are transported to the rest of the plant vis thee xylem.

Question 26

Describe the gaseous exchange at the stomata of leaves.

Answer 26

There is a higher concentration of carbon dioxide in the atmospheric air than inside thee leaf. Carbon dioxide diffuses from the air and into the leaf. There is a higher concentration of oxygen inside the leaf than in the atmospheric air. Oxygen diffuses from thee inside of the leaf across the stomata into the atmospheric air.

Question 27

Define osmosis.

Answer 27

Osmosis is the net movement of water molecules from a region of higher water potential to a region of lower water potential across a partially permeable membrane.

Question 28

Describe absorption of water at the root hair cell.

Answer 28

Higher water potential in the soil solution than in the root hair cells by osmosis across the partially permeable membrane. Water molecules move across the root cells into the xylem where water is transported to the rest of the plant.

Question 29

Explain what happens to a plant cell when it is placed in concentrated salt solution.

Answer 29

There is higher water potential in the plant cell than in the salt solution. o water molecules exit the plant cell across the plant cell to the salt solution to the cell membrane via osmosis. So the vacuole decreases in size and the cytoplasm shrinks away from the cell wall.