Mass Transport in Animals Flashcards
1
Q
What is digestion?
A
Where large biological molecules are hydrolysed by enzymes into smaller molecules that can be absorbed across cell membranes
2
Q
Digestion of carbohydrates
A
- Amylase produced by salivary glands hydrolyses starch into maltose
- Maltose hydrolysed by maltase into glucose
- Membrane bound disaccharides attached to the ileum also help hydrolyse maltose into glucose
3
Q
Digestion of lipids
A
- Bile salts produced by liver emulsify lipids, increasing SA:V of lipid droplets
- Lipase hydrolyses lipid droplets into micelles
- Micelles contain bile salts and fatty acids
- Micelles make fatty acids soluble and bring to cell lining the ileum
- Fatty acids absorbed by diffusion
- Triglycerides reformed in cells
- Vesicles move to membrane
4
Q
Digestion of proteins
A
- Endopeptidase hydrolyse peptide bonds within polypeptide
- Exopeptidase hydrolyses peptide binds at ends of polypeptide
- Membrane bound dipeptidase hydrolyse peptide bonds between dipeptides
5
Q
Amino acid absorption
A
- Co-transport with Na+
- Na+ pumped out, creating low concentration of Na+
- Na+ diffuses in via co-transport
- Amino acids co-transported in too against concentration gradient
6
Q
What is haemoglobin?
A
A protein with a quaternary structure found in red blood cells. Oxygen binds forming oxyhaemoglobin
7
Q
Oxyhaemoglobin dissociation curve
A
- Oxygen loads onto haemoglobin at high partial pressure of oxygen
- Haemoglobin becomes saturated with oxygen
- Oxygen unloads at the cells where partial pressure of oxygen is low
8
Q
The Bohr shift
A
- Oxyhaemoglobin curve shifts to the right
- Organisms respire, increasing concentration of carbon dioxide in blood
- Increased blood acidity decreases haemoglobin affinity for oxygen
- Oxygen unloads more easily at respiring cells, becoming less saturated with oxygen
9
Q
Organisms in low oxygen environments oxyhaemoglobin curve
A
- Lower partial pressure of oxygen in lungs
- Haemoglobin has a higher affinity for oxygen
- Able to load oxygen at lower partial pressure of oxygen
10
Q
Organisms in high oxygen environments oxyhaemoglobin curve
A
- Higher partial pressure of oxygen in lungs
- Haemoglobin has a lower affinity for oxygen
- Unload more oxygen at cells
- Useful for animals with high rate of respiration (eg. Small SA:V animals loose more heat per gram)
11
Q
Arteries structure (+ function)
A
- Narrower lumen (blood at high pressure)
- Elastic tissue and folded endothelium (stretch and recoil, maintaining smooth pressure)
- Thick muscle (contract and change flow of blood)
12
Q
Vein structure (+ function)
A
- Wide lumen (blood at low pressure)
- Smooth endothelium (reduce friction)
- Thin muscle (can’t contract)
- Valves (prevent backflow of blood)
13
Q
Capillaries structure (+ function)
A
- One cell thin endothelium (short diffusion distance)
- High surface area (fast rate of diffusion)
- High hydrostatic pressure at start of capillaries (outward pressure forces fluid out capillaries)
14
Q
Heart structure (+ function)
A
- Aorta (oxygenated blood to body)
- Pulmonary vein (oxygenated blood from lungs)
- Left atrium (pimps blood to ventricle)
- AV valves (open when pressure is greater in atria)
- Left ventricle (thicker muscle, pumps blood around body)
- Pulmonary artery (deoxygenated blood to lungs)
- Vena Cava (returns blood from body)
- Right atrium (pumps blood to ventricle)
- SL valves (open when pressure is higher in ventricles)
- Right ventricle (pumps blood to lungs)
15
Q
Cardiac cycle
A
- Atria contracts
- Pressure higher in atria than ventricles
- AV valves open and SL valves close
- Ventricles contract
- Pressure higher in ventricles
- AV valves close and SL valves open
- Atria and ventricles relax
- Pressure higher in atria than ventricles
- AV valves open and SL valves close
