Transport in Animals

Question 1

why are specialised transport systems needed in animals?

Answer 1

• High metabolic demands
• Small SA:V ratio
• Transport of molecules, food and waste products

Question 2

What are the 2 types of circulatory systems?

Answer 2

Open and closed

Question 3

What are the features of an open circulatory system?

Answer 3

• Blood comes into direct contact with cells

- Few vessels

Question 4

What’s a haemocoel?

Answer 4

Body cavity of an animals

Question 5

What organisms are open circulatory systems mainly found in?

Answer 5

Insects

Question 6

What are the features of a closed circulatory system?

Answer 6

• Blood is enclosed in blood vessels

- Blood doesn’t come into direct contact with cells

Question 7

What organisms are closed circulatory systems mainly found in?

Answer 7

Fish/mammals

Question 8

What are the 2 types of closed circulatory system?

Answer 8

Single and double

Question 9

How does a single closed circulatory system work?

Answer 9

Blood only travels through the heart once in every circuit around the body

Question 10

Give an example of an organism that has a single closed circulatory system

Answer 10

Fish

Question 11

Which organisms use a double closed circulatory system?

Answer 11

Most mammals

Question 12

Explain the 2 circulations in a double closed circulatory system?

Answer 12

• Blood travels through the heart twice per circuit
• Oxygenated around body
• Deoxygenated to lungs

Question 13

What is the name of the circulation that carries blood to the lungs in a double closed circulatory system?

Answer 13

Pulmonary circulation

Question 14

What is the name of the circulation that carries blood to the rest of the body in a double closed circulatory system?

Answer 14

Systemic circulation

Question 15

When O2 binds loosely to haemoglobin, what forms?

Answer 15

Oxyhaemoglobin

Question 16

Write the balanced equation for haemoglobin binding to oxygen

Answer 16

Hb + 4O₂ Hb(O₂)₄

Question 17

Explain the process of oxygen binding to haemoglobin

Answer 17

• Erythrocytes enter capillaries in the lungs
• Oxygen from alveoli diffuses into erythrocyte and binds to Hb
• Positive cooperativity occurs
• Steep diffusion gradient is maintained until all the Hb is saturated with O2

Question 18

What is positive cooperativity?

Answer 18

The previous O2 molecule gives an increased affinity for the next one

Question 19

What is affinity?

Answer 19

How easy Hb is able to associate with O2

Question 20

What does saturated refer to?

Answer 20

the number of O2 molecules associated with Hb

Question 21

How does Hb release O2?

Answer 21

• Conc of O2 in cytoplasm is lower than in erythrocyte
• O2 diffuses out of erythrocyte
• Once first molecule is released, Hb changes shape to give easier removal of further molecules

Question 22

What is plotted on an O2 dissociation curve?

Answer 22

• Percentage saturation

- Partial pressure of O2

Question 23

What are the units for partial pressure of O2?

Answer 23

PO₂/kPa

Question 24

Explain the oxygen dissociation curve

Answer 24

• Low affinity for 1st O2 molecule at low pressure
• As pressure increases so does affinity (positive cooperativity)
• At highest pressure, most binding sites are occupied so no more O2 molecules can bind

Question 25

What is the Bohr effect?

Answer 25

As the partial pressure of CO2 rises, Hb gives up O2 more easily

Question 26

Where does a foetus get its O2 from?

Answer 26

Oxygenated mother blood in placenta

Question 27

Why does fetal Hb have a higher O2 affinity?

Answer 27

To associate the necessary O2 from the mother blood in placenta

Question 28

What percentage of CO2 is dissolved in plasma?

Answer 28

5%

Question 29

What percentage of CO2 takes the form of carbaminohaemoglobin?

Answer 29

10-20%

Question 30

What percentage of Co2 is stored as HCO3- in cytoplasm of RBC?

Answer 30

75-85%

Question 31

What does H2CO3 dissociate into?

Answer 31

H+ ion and HCO3- ion

Question 32

How is CO2 converted into H2CO3?

Answer 32

By the enzyme carbonic anhydrase

Question 33

How is H+ removed?

Answer 33

Buffers, especially Hb

Question 34

What happens to the H+ ion?

Answer 34

- Binds allosterically to Hb - Changed Hb tertiary structure (dissociates from O2) - Forms haemoglobinic acid

Question 35

What happens to the hydrogen carbonate ion?

Answer 35

- Diffuses out of the RBC to maintain a conc gradient so CO2 continually diffuses into RBC

Question 36

What is chloride shift?

Answer 36

HCO3- ions diffuse out of RBC and are replaced by CL- ions from plasma to balance loss of negative charge