Mass Transport

Question 1

What are fats broken down into

Answer 1

Fatty acids and monoglycerides

Question 2

What are proteins broken into

Answer 2

Amino acids

Question 3

Digestion

Answer 3

Process by which larger molecules are hydrolysed to smaller molecules that can be absorbed across cell membranes

Question 4

Amylase

Answer 4

Breaks down carbohydrates
Catalyses conversion of starch into maltose by hydrolysing glycosidic bonds
Produced by salivary glands
Membrane bound dissacharides are enzymes that attach to membrane of epithelial cell lining break down dissacharides

Question 5

Membrane bound dissachridases

Answer 5

Enzymes that are attached to cell memebrane of epithelial cell lining the ileum
Break down dissacharides into monosaccharides

Question 6

Lipase

Answer 6

Catalyse break down of lipids into monoglycerides and fatty acids by hydrolysing Ester bonds
Made in Pancreas and in small intestine
Fats and oils broken down into micelles by biles salts by emulsification
Triglycerides broken down into monoglycerides

Question 7

Endopeptidases

Answer 7

Hydrolysed peptide bonds in central region of protein forming series of peptide molecules
Trypsin and chymotrypsin produced by pancreas then in small intestine
Pepsin works in acidic conditions

Question 8

Exopeptidases

Answer 8

Hydrolysed peptide binds I’m terminal amino acids of the peptide molecules formed by endopeptidases. They remove single amino acids

Question 9

Dipeptidasea

Answer 9

Hydrolyse bonds between amino acids of a peptide. Part of cell surface membrane of epithelial cells lining the ileum

Question 10

Haemoglobin

Answer 10

Large protein with a quarternary structure of 4 chains

Question 11

Haemoglobin Structure

Answer 11

Large protein with quarternary structure with 4 polypeptide chains
Each chain has haem group with contains iron ion (gives red colour)
Can carry 4 oxygen molecules at once

Question 12

High affinity

Answer 12

High attractive force

Readily associates with O2

Question 13

Low affinity

Answer 13

Lower association with oxygen but readily dissociates

Question 14

Low partial pressure

Answer 14

Hb has a low affinity for oxygen therefore readily dissociates meaning low saturation

Question 15

Bohr effect

Answer 15

Cells respire raising the pCO2
This increases oxygen unloading rate shifting the curve right
Saturation of blood with O2 lower for given pO2 meaning more oxygen released

Question 16

Loading

Answer 16

CO2 is constantly being removed so there’s a lower concentration so pH is raised
The shape of the protein changes and the affinity of haemoglobin increases

Question 17

Active animals

Answer 17

Have lower affinity

Question 18

Vena cava

Answer 18

Carries deoxygenated blood to the heart

Question 19

Aorta

Answer 19

Carries oxygenated blood to the body

Question 20

Pulmonary artery

Answer 20

Carries deoxygenated bloody to the lungs

Question 21

Artery

Answer 21

Carry oxygenated blood from the heart to the rest of the body
Thick muscular walls prevent bursting
Elastics tissues to stretch and recoil during pumping to maintain pressure
Pulmonary artery carries deoxygenated blood to lungs

Question 22

Veins

Answer 22

Carry deoxygenated bloody back to the heart under low pressure
Have wide lumen but little muscle or elastic
Have valves to prevent back flow
Blood flow helped by contractions is body muscles surrounding
Pulmonary veins carry oxygenated blood from lungs to heart

Question 23

Capillary

Answer 23

Walls have thin lining layer for short diffusion path way
Large SA for exchange
Narrow diameter for short diffusion pathway
Narrow lumen so RBC squeezes against capillaries
Have spaces between lining so WBCs can escape to deal with infection

Question 24

Tissue fluid formation

Answer 24

At start if capillary bed the hydrostatic pressure inside capillaries greater than tissue fluid so fluid pushed out into spaces around the cells
Hydrostatic pressure in capillaries reduces lower and Venule end of bed
Increase in plasma protein at venule end the WP is Lower than tissue fluid
Water re-enters capillaries at venule end via osmosis

Question 25

Cardiac Cycle

Answer 25

Ventricles and atria are relaxed, the atria contract decreasing volume of the chambers and increasing pressure blood pushed into ventricles
Atria relax and ventricles contract increasing pressure so AV valves shut. Pressure higher than in aorta and pulmonary artery opening SL valves and blood into arteries
Ventricles and atria relax, higher pressure in pulmonary artery and aorta closing SL vales
Blood returns to the heart and atria full due to higher pressure in vena cava and pulmonary vein
Ventricles relax do AV valves open allowing passive flow of blood

Question 26

Coronary heart disease

Answer 26

When many atheromas on coronary arteries restricting blood flow to the heart muscle

Question 27

Aneurysm

Answer 27

Atheromas weaken arteries narrowing arteries increasing blood pressure
Blood travels through weakened artery at high pressure can push through to elastic layer forming swelling

Question 28

Thrombosis

Answer 28

Atheromas can rupture endothelium causing platelets and fibrin to accumulate to form a clot

Question 29

Cholesterol

Answer 29

LDL can stick to lining of blood vessels and build up forming plaque which narrows arteries and makes less flexible
Blood flow reduced

Question 30

Smoking

Answer 30

CO has high affinity to Hb which reduces oxygen carrying capacity
Adrenaline increases BP
Reduces antioxidants which protect cells

Question 31

Blood pressure

Answer 31

Increases damage to the artery walls
Can lead to stroke
Heart has to work harder to pump blood at high pressure and lead to aneurysm

Question 32

Xylem vessels

Answer 32

Long tube like structures formed form dead cells

Question 33

Factors affecting transpiration

Answer 33

Light: Lighter it is the faster the rate as stomata open when light to allow CO2 for photosynthesis
Temperature: warmer particles have more energy to evaporate increasing conc gradient between inside and out leaf
Humidity: if air is dryer the conc gradient is increased
Wind: the conc gradient is increased if more wind due to movement of water molecules

Question 34

Translocation

Answer 34

Movement of minerals and organic molecules from one part of a plant to another

Question 35

Mass flow theory

Answer 35

Active transport used to actively load solutes from companion cells to sieve tubes of phloem at source
Lowers WP in sieve tubs so water enter by osmosis from xylem creating high pressure inside sieve tubes at source end
At sink solutes removed from the phloem to be used up increasing WP inside the sieve tubes sk water leaves by osmosis
Results in pressure gradient from source end to the sink which pushes solutes towards the sink