Transport Systems

Question 1

Why do all organisms need a transport system? 4

Answer 1

• All cells need energy
• Energy requires respiration
• Respiration requires raw materials e.g glucose/oxygen
• Must be delivered to all cells

Question 2

What do unicellular organisms have meaning they can use diffusion as a transport system?

Answer 2

• A high surface area to volume ratio
• Short distance to needed cells, substances can diffuse directly across cell membrane
• It transports nutrients to it fast enough to meet its small energy requirements

Question 3

What type of transport system do unicellular organisms use?

Answer 3

Diffusion

Question 4

Define “unicellular”.

Answer 4

Single celled organism

Question 5

Why can’t multicelluar organisms rely on diffusion?

Answer 5

• Low surface area to volume ratio
• Large distances need to be travelled to reach all cells
• Diffusion is too slow to meet
  requirements of high metabolic rate and energy needs

Question 6

What do multicellular organisms need for transport?

Answer 6

• A mass transport system that moves substances effectively over long distance by mass flow
• Specialised organs e.g lungs increase SA:Vol ratio for effective exchange

Question 7

What is the main type of mass transport system?

Answer 7

The circulatory system

Question 8

What is mass flow?

Answer 8

The circulation of blood maintaining a high concentration gradient

Question 9

What does blood do in the circulatory system?

Answer 9

Carries raw materials from specialised organs to body cells and removes metabolic waste

Question 10

What are the 4 types of circulatory system?

Answer 10

• Open
• Closed
• Single
• Double

Question 11

What organisms use an open circulatory system?

Answer 11

• Small multicellular organisms

- E.g insects, earthworms

Question 12

Describe an open circulatory system. 5

Answer 12

• Blood carrying vital substances circulates in open large spaces
• Heart pumps blood out into cavities surrounding animal’s organs
• Substances diffuse between blood and cells
• Heart muscle relaxes
• Blood is drawn from the cavity back into the heart through small valved openings along its length

Question 13

What type of organisms use closed circulatory system?

Answer 13

Large multicellular

Question 14

Why do large multicellular organisms need a closed circulatory system?

Answer 14

Larger and more active

Question 15

Where is blood in a closed circulatory system?

Answer 15

Blood is enclosed within tubes - blood vessel

Question 16

Describe a closed circulatory system. 4

Answer 16

• Blood vessels generate high pressures
• Blood is forced along narrow channels instead of flowing into large cavities
• Flows along arteries then arterioles then capillaries
• Blood returns to heart through venules then veins

Question 17

Give an organisms that has a single circulatory system.

Answer 17

Fish

Question 18

Describe a single circulatory system in fish.

Answer 18

• Heart pumps deoxygenated blood to gills
• Gaseous exchange takes place in the gills [Co2 from blood to water surrounding gills and vice versa with oxygen]
• Blood leaving gills flows around rest of body before returning to heart

Question 19

Define “single circulatory system”

Answer 19

Blood flows through heart once for each complete circuit of the body

Question 20

Define “double circulatory system”

Answer 20

Blood flows through heart twice for each complete circuit of the body

Question 21

What organisms use a double circulatory system?

Answer 21

Birds and mammals with a high metabolic rate

Question 22

Describe a double circulatory system. 2

Answer 22

• Right ventricle of the heart pumps deoxygenated blood to the lungs
• Oxygenated blood returns to the heart to be pumped a second time by left ventricle out to the rest of the body