B5 Exhange Of Materials

Question 1

Complete the sentence

Humans and other animals must ……… the substances they need from the environment and ……… of any waste products.

Answer 1

Take in

Get rid

Question 2

What do cells need oxygen for?

Answer 2

Aerobic respiration

Question 3

What is the waste product of aerobic respiration?

Answer 3

Carbon dioxide

Question 4

How do oxygen and carbon dioxide move between the cells and the environment?

Answer 4

By diffusion

Question 5

Water is needed for many chemical reactions. How is it taken up by the cells?

Answer 5

By osmosis

Question 6

What is taken up by cells during osmosis?

Answer 6

Water and dissolved food molecules

Question 7

Where are the dissolved food particles from that get taken up along with water through osmosis?

Answer 7

Products of digestion

Eg amino acids and glucose

Question 8

What are the water and dissolved food particles taken up during osmosis used for?

Answer 8

Synthesis reactions

See p51

Question 9

What is urea?

Answer 9

A waste product from the breakdown of proteins in the liver.

Question 10

Complete this sentence

Urea diffuses from …… into the …….

Answer 10

Cells

Blood plasma

Question 11

How is urea filtered out of the blood?

Answer 11

By the kidneys and excreted as urine.

Question 12

Complete the sentence

How easy it is for an organism to exchange substances with its environment depends on the organisms ………….. to …….. ratio.

Answer 12

Surface area

Volume

Question 13

What does SA:V show?

Answer 13

How big one value is compared to another.

Question 14

Complete the sentence

The larger the organism is, the ……… its surface area is compared to its ……..

Answer 14

Smaller

Volume

Question 15

See page 67 for calculating surface area to volume ratio

Answer 15

.

Question 16

Why do urea and CO2 need to be removed from the body?

Answer 16

Because they are toxic, if the reach a certain level.

Question 17

Complete the sentence

Multicellular organisms have relatively ….. surface area to volume ratios, which makes ………. to and from cells deep within their bodies slow.

Answer 17

Small

Diffusion

Question 18

Complete the sentence

Multicellular organisms have a relatively small surface area to volume ratio, this makes it difficult to exchange ………… to supply their ………. across their outside surface alone.

Answer 18

Enough substances

Entire volume

Question 19

How do multicellular organisms get enough substances to supply their entire volume?

Answer 19

They usually have specialised exchange surfaces to increase their SA:V.

Question 20

What do specialised exchange surfaces do?

Answer 20

They increase their SA:V and therefore the rate at which substances are able to diffuse.

Question 21

What is a mass transport system?

Answer 21

A circulatory system

Question 22

What does a mass circulatory system do?

Answer 22

Moves substances around the body, this shortens the distance these substances have to diffuse to and from cells.

Question 23

Give an example of a small multicellular organisms that has a big enough SA:V that they don’t need specialised exchange surfaces.

Answer 23

Worms

Question 24

Name the 4 systems that need to work together for all movement into, out of and around the human body.

Answer 24

Gaseous exchange systems
Circulatory systems
Digestive systems
Excretory systems

Question 25

See p 67 for question

Answer 25

See page 116 for answer