Exchange and transport

Question 1

Why is diffusion fast in single celled organisms?

Answer 1

has to travel short distance

have high SA:V ratio

Question 2

How does having a large surface area help root hair cells

Answer 2

-increases rate of absorption of water and mineral ions

Question 3

How does being thin help the alveoli

Answer 3

There is a shorter diffusion pathway

Question 4

How does having a good blood supply help the alveoli

Answer 4

• surrounded by dense capillary network

- which creates a steep concentration gradient

Question 5

How does having a good blood supply help the gills

Answer 5

gills contain dense network of capillaries
also they are well ventilated due to water
-maintains steep concentration gradient

Question 6

What is the structure of the gaseous exchange system

Answer 6

trachea splits into bronchi
bronchus leads to bronchioles
which leads to alveoli

Question 7

What is the function of a goblet cell

Answer 7

• secretes mucus to trap microorganisams and dust particles

- stops them from reaching alveoli

Question 8

What is the structure and function of cillia

Answer 8

structure

• made from microtuberoules 9+2
• have hair like structure

functions
-waft/beat the mucus up the air way towards the throat (helps prevent lung infections)

Question 9

What is the structure and function of cartilage

Answer 9

-c shaped rings

function

• provide support
• stops trachea from collapsing
• rings provide flexablity

Question 10

What is the function of smooth muscle

Answer 10

• allows diameter to be controlled (I think mark schemes like to say constrict)
• can make air tubes wider to decrease resistence to air flow

Question 11

What is the function of elastic fibres

Answer 11

they streach and recoil when breathing in and out

prevent alveoli from bursting

Question 12

where is cartilage found

Answer 12

trachea

small amounts on bronchi

Question 13

Where is smooth muscle found

Answer 13

trachea, bronchi, broncheloles

but not in small broncheloles or the alveoli

Question 14

Where are elastic fibres found

Answer 14

EVERYWHERE

Question 15

Where are goblet cells

Answer 15

trachea, bronchi, large broncheoules

not found in smaller broncheoles, or the alveoli

Question 16

Where are epithelium cells found

Answer 16

Cillaited
trachea, bronchi, large bronchi

squamous
alveoli

Question 17

What happens during forced expiration

Answer 17

internal intercostal muscles contract, which pull ribcage down and in

Question 18

What happens during inspiration

Answer 18

• intercoastal muscles and diagraphm contract
• causes ribcage to move upwards and outwards
• volume of throax increases so lung pressure decreases below atmospheric pressure
• so air comes into lungs

Question 19

What happens during expiration

Answer 19

-intercostal muscles and diaphragm relax
-causes ribcage to move downwards and inwards
-volume of throax decreaes
-air pressure increses (above atmospheric pressure)
air is expelled from lungs

Question 20

State the meaning of tidal volume

Answer 20

volume of air in each breath

usually 0.4 dm3

Question 21

State the meaning of vital capacity

Answer 21

max volume of air that can be breathed in or out

Question 22

State the meaning of breathing rate

Answer 22

how many breaths taken per minute (any unit of time really)

Question 22

State the meaning of oxygen uptake

Answer 22

rate at which a person uses up oxygen

Question 23

How do we use a spirometre

Answer 23

• breathe into a tube
• then a pen records the movement which is attached to the lid of the chamber
• this creates a spirometre trace
• can also use a data logger

Question 24

Why does the total volume of gas in a spirometre decrease

Answer 24

• air breathed out is a mix of CO2 and O2
• co2 absorbed by soda lime
• as oxygen is used up in respiration so total volume decreases

Question 25

Why must the person wear a nose clip when using a spirometre

Answer 25

• ensures they can only breathe in and out through their mouth
• gives a valid reading

(btw the machine must be airtight)

Question 26

What is the structure of gills

Answer 26

-Gill made out of gill fillaments (primary lamelle)
these have thin walls and lots of capilaries
- these are covered by gill plates (secondary lamelle) which further increases surface area
-each gill is supported by a gill arch

Question 27

Explain the countercurrent system

Answer 27

• blood flows through gills in one direction and water in the opposite
• this means water with high o2 flows next blood with low o2
• so a steep concentartion gradient can be mainatined
• this makes sure as much o2 can diffuse into blood

Question 28

How are fish gills ventilated

Answer 28

• fish mouth opens, lowers floor of buccal cavity
• vol of buccal cavity and pressure decreases
• so water rushes in
• fish closes its mouth and the buccal cavity is raised
• volume decreases and pressure increases
• water is forced out of cavity into the gills
• operculmn feels increased pressure so it forces head to open
• water leaves fish

Question 29

How are insects ventilated

Answer 29

1. Air enters spiricales (which can be open or closed to prevent water loss
2. travels to trachea then tracheoles
3. o2 diffuses into tracheal fluid, which diffuses into cells
4. co2 diffuses out of cells into trachea and out of spircales

Question 30

How can insects ventilate themselves during exercise

Answer 30

1. Tracheal fluid moves into cells via osmosis
2. this occurs when lactic acid builds up in cells
   - which decreases water potential so more gas exchange happens

Question 31

How can an insect change its body to move air in and out

Answer 31

-Can use rhythmic abdominal movements to change volume of body

Question 32

How do flying insects ventilate themselves and when do they do this

Answer 32

• use movements to pump throax
• in large insects air sacs help mechanically pump air through system
• this happens when their is a higher energy demand