Topic 3

Question 1

Ventilation

Answer 1

Breathing

Question 2

Respiration

Answer 2

Chemical reaction to release energy

Question 3

Inspiration

Answer 3

Breathing in - active process

The external inter coastal muscles - contract

Internal inter coastal musicals - relax

The ribs are pulled upwards and outwards

The diagraphs muscles contract causing it to flatten increasing the volume of the thorax

The increased volume of the thorax results in the reduction of pressure in lungs
Atmospheric pressure now greater
Air forces out lungs

Question 4

Expiration

Answer 4

Breathing out passive process

Internal inter coastal muscle contract

Ribs moves downwards and inwards
Diaphragm relaxes and returns to some shape
Decreasing the volume of the thorax
Increasing pressure in lungs
Air forces out the lungs

Question 5

Pulmonary ventilation

Answer 5

Tidal volume x ventilation rate

Question 6

Gas exchange in alveoli

Answer 6

Alveolar epithelium
Tiny air sacks create a large surface area for gas exchange

Epithelial cell are very thin short diffusion path way

Rich blood supply to maintain concentration gradient

Question 7

Gas exchange in plants

Answer 7

Gas exchange at stomata
Oxygen diffuses out - if not needed for respiration
Carbon dioxide diffuses in - needed for photosynthesis

Question 8

Reduce water loss in plants

Answer 8

Stomata closes at night when photosynthesis doesn’t occur

Question 9

Xerophytic plants

Answer 9

Adapted to survive with limited water
Have structural features
Enable efficient gas exchange to occur
Whilst limiting water loss

Question 10

Structure for xerophytes

Answer 10

Thicker cuticle - reduce evaporation
Hairs to trap moisture- increase humidity
Longer root network to reach more water
Thicker cuticle to reduce water loss

Question 11

Terrestrial Insects

Answer 11

Exoskeleton is water proof
Prevents water loss

Hard fibrous material is for protection
However makes it hard for gasses to enter

Question 12

Tracheal system

Answer 12

Trachea - is a network of internal tubes
Tubes have rings within them
Strengthen the tubes and keep them open

Tracheoles -branched out
Extend through your the tissue in insects to deliver oxygen to respiring cells

Spiracles -
Round value like openings
Long around the abdomen
Oxygen carbon dioxide enter and leave via spiritless
Trachea attached to these opening

Question 13

Gas exchange in insects

Answer 13

1. Along a diffusion gradient
   When cells respire they use Up oxygen and produce co2
   -Creating a concentration gradient
   From tracheolos to atmosphere
2. Mass transport
   Insects contract and relax their abdominal muscles to move hasses
   This futher speeds up the exchange of respiratory gases

3.the end of the tracheols are filled with water

1.Muscle cells respite carrying out an anaerobic respiration - produced lactate

2.Lowers the water potential of fells
Water moves from tracheols into cells via osmis
3.Decrease volume in tracheols
4.More air from atm draws in

Question 14

Adaptations to prevent water loss in insects

Answer 14

Small surface area to volume ratio
- water can evaporate

Waterproof exoskeleton
Spiricales open and close

Question 15

Fish

Answer 15

Waterproof
Have small surface area to volume ratio
Require gas exchange - gills
Need adaptations

Question 16

Adaptation for gas exchange

Answer 16

Large surface to volume ratio - created by many gill filaments covered in many gill lamellae

Short diffusion distance - due to capillary network in every lamellae and very thin lamellae

Maintain concentration gradient - countercurrent flow mechanism

Question 17

Conentercurrent gradient

Answer 17

Water flows over gills opposite direction to blood following through capillary

Advantage -
Make sure the equilibrium of oxygen not reached

Ensures that a diffusion gradient is maintained across the entire length of the hill

Question 18

Digestion

Answer 18

Large biological molecules are hydrolysed into smaller molecules that can be absorbed across cell membrane

Question 19

Digestion in mammals

Answer 19

Carbs
Lipids
Protein

Begin in mouth continues in duodenum
Completed in illuem

Question 20

Carbohydrates

Answer 20

Two enzymes hydrolyses into monosaccharides

1. Amylase
2. Membrane bound disaccharide
3. Amylase is produced in salvariry gland
4. Hydrolyses the polysaccharide into disaccharides maltose by hydrolysing glycosidic bonds
5. Sucrase and lactase
   - membrane bound
   Hydrolyse sucrose and lactose into monosaccharides

Question 21

Proteins

Answer 21

Large polymer molecules
- can be hydrolysed by 3 enzymes

1. Endopeptidases
   -hydrolyse peptide bonds between amino acids in the middle of polymer chain
2. Exopeptidases
   - hydrolyse peptide bonds between amino acids at the end of the polymer chain
3. Membrane bound dipetodases
   - hydrolyse peptide bonds between two amino acids

Question 22

Lipids

Answer 22

1.Digested by lipase
2.Action of bile salts

1. Lipase
   -Produced in pancreas’s
   -Hydrolyses the ester bond in triglycerides
   -To for’ monoglycerides and fatty acids

2.bile salts
-produced in liver
-emulsify lipids to form tiny droplets - micelles
- micelles increase surface for lipase to act on

Question 23

Lipid absorbtion

Answer 23

Micelles encounter the illuem epithelial cell due to non polar nature of fatty acid and mono glysceriedes

They can simply diffuse across cell surface membrane to enter the cells of epithelial

Once In cells
-Modify back into triglyceride inside the endoplasmic rectifulum and golgy box

Question 24

Absorbtion

Answer 24

Products of absorbtion are digested across the cell lining of illuem

Question 25

Adaptations of absorbtion

Answer 25

Ileum wall covered in villi
- surface area

have thin wallls
-short diffusion path way

Concentration gradient
- network of capillaries