B8 Respiration, The Circulatory System

Question 1

What is respiration?

Answer 1

• exothermic process that releases energy in the form of ATP
• generated from breakdown of glucose

Question 2

What is ATP?

Answer 2

• short term energy store in all cells
• universal energy carrier

Question 3

What is aerobic respiration?

Answer 3

• respiration in the presence of oxygen
• forms ATP from the breakdown of glucose

Question 4

What is anaerobic respiration?

Answer 4

• respiration taking place without oxygen
• forms ATP from breakdown of glucose

Question 5

When may anaerobic respiration take lace in plant cells?

Answer 5

If soil is waterlogged

Question 6

What is the word equation for anaerobic respiration in muscle cells?

Answer 6

Glucose -> Lactic acid (+ATP)

Question 7

What is the word equation for anaerobic respiration in plant and yeast cells?

Answer 7

glucose -> ethanol + carbon dioxide (+ATP)

Question 8

Why may anaerobic respiration eventually cause the muscles to stop?

Answer 8

Lactic acid build up inhibits anaerobic respiration

Question 9

What is more efficient and why - aerobic or anaerobic respiration?

Answer 9

• aerobic
• produces more molecules of ATP

Question 10

What are red blood cells also known as?

Answer 10

Erythrocytes

Question 11

How do red blood cells transport oxygen to body cells?

Answer 11

• lungs - haemoglobin in red blood cells bind reversibly to oxygen to form oxyhaemoglobin
• tissues - oxyhaemoglobin breaks down to form haemoglobin and oxygen which diffuses into cells

Question 12

What is the function of platelets?

Answer 12

Blood clotting

Question 13

How are red blood cells specialised?

Answer 13

• bio-concave disks (increase diffusion rate)
• no nucleus (increase space for haemoglobin)
• small and flexible (move through capillaries)
• thin (low diffusion distance)

Question 14

What is plasma?

Answer 14

• pale yellow liquid portion of blood
• contains proteins, nutrients, hormones, waste products and antibodies

Question 15

How is plasma adapted?

Answer 15

Consists mainly of water (acts as solvent, allowing materials to be carried around the body)

Question 16

How are arteries adapted?

Answer 16

• narrow lumen (high blood pressure maintenance)
• thick outer walls (withstand pressure)
• thick layer of muscle (strength)
• thick layer elastic fibres (stretch)
• smooth inner lining (reduces friction)
• no valves

Question 17

How are the capillaries adapted to their function?

Answer 17

• once cell thick (short diffusion)
• walls permeable (allow exchange)
• narrow lumen (decrease the diffusion distance)

Question 18

What is the pulmonary circuit?

Answer 18

• part that involves right side of heart
• deoxygenated blood to lungs
• alveoli - capillary gas exchange
• oxygenated blood returned to left side of heart

Question 19

What is the systemic circuit?

Answer 19

• involves left side of heart
• oxygenated blood pumped around body
• exchange of materials occurs at tissues
• deoxygenated blood returns to right side of heart

Question 20

What is cardiac output?

Answer 20

The volume of blood pumped out of heart per minute

Question 21

What is stroke volume?

Answer 21

The volume of blood pumped out of ventricle in one contraction

Question 22

How is cardiac output calculated?

Answer 22

Cardiac output (cm³ min⁻¹) = heart rate (bpm) X stroke volume (cm³)

Question 23

Why do multicellular organisms require specialised exchange surfaces?

Answer 23

• small SA/V
• diffusion insufficient to provide for all cells
• these surfaces increase rate of diffusion and decrease diffusion distance

Question 24

How does the size of the organism affect its surface are to volume ratio?

Answer 24

The larger the organism, the smaller the SA/V