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3.2 (red), 3.3 human (purple) and 3.3 plant (green)
what is hydrolysis?
when a water molecule is needed to break down a larger molecule
why is hydrolysis used in digestion?
to make the larger molecules small enough so they can diffuse into cells
what does the hydrolysis of proteins create?
amino acids
what does the hydrolysis carbohydrates of create?
monosaccharides and disaccharides
what does the hydrolysis lipids of create?
fatty acids and monoglycerides
what does amylase do?
hydrolyses starch into maltose
what bond is broken in the hydrolysis of carbohydrates?
glycosidic bonds
where can the membrane-bound disaccharidases be found?
in the epithelial cells in the ileum
what do membrane-bound disachharidases hydrolyse?
disachharides
how is glucose and galactose transported into the epithelial cells?
via co-transport proteins
how is fructose transported into the epithelial cells?
facilitated diffusion
where is amylase produced?
salivary glands and pancreas
where is lipase produced?
pancreas
where does lipase work?
small intestine
what enzyme is used for lipid digestion?
lipase
what bond does lipase hydrolyse?
ester bonds
where are bile salts produced?
liver
what do bile salts do?
forms small droplets called micelles by emulsifying the lipids
what do micelles do?
create a larger surface area for lipase to work on
how are mologlycerides and fatty acids absorbed into the epithelial cells?
simple diffusion
what does endopeptidase do?
hydrolyses the peptide bond WITHIN a protein
what does exopeptidase do?
hydrolyses the peptide bond AT THE END of a protein
how are amino acids absorbed into the blood?
co-transport
describe the process of co-transport?
sodium ions are actively transported out of the cell, causing a concentration gradient to form
this allows for sodium ions to diffuse into the cell within a co-transported alongside glucose/amino acids
then the cell either uses the monomer or it is absorbed into the blooidstream
what type of protein is haemoglobin?
globular
how does haemoglobin have a quarternary structure?
made of four polypeptide chains
what is called when haemoglobin binds to oxygen?
oxyhaemoglobin
how many oxygen molecules bind to one haemoglobin?
four
what does the oxygen do when it reaches the muscle cells?
it dissociates
how is haemoglobin red?
iron in the haem group
what is the partial pressure of oxygen?
concentration of oxygen within the cells
what is the partial pressure of carbon dioxide?
concentration of carbon dioxide within the cells
when does oxygen bind to haemoglobin?
when the pO2 is high
when does the oxygen dissociate from the haemoglobin?
when the pO2 is low
when is there a high affinity of oxygen?
when the pO2 is high
when is there is low affinity of oxygen?
when the pO2 is low
why do animals who live in higher altitudes have higher affinity of haemoglobin?
the air has a lower when pO2 than the sea level
why do animals with a high metabolic rate have oxygen which dissociates easily?
oxygen is easily supplied to respiring cells
what happens when there is a low pO2?
oxygen dissociates/low % of haem groups full
what shape is the oxygen dissociation curve?
s-shaped
what is the bohr effect?
a shift in the oxygen dissociation curve to the right due to carbon dioxide
what type of circulation do mammals have?
double-circulation
what blood vessel pumps deoxygenated blood from the heart to the lungs?
pulmonary artery
what blood vessel pumps oxygenated blood from the lungs to the heart?
pulmonary vein
what blood vessel pumps oxygenated blood from the heart to the body?
aorta
what blood vessel pumps deoxygenated blood from the body to the heart?
vena cava
which blood vessel supplies oxygenated blood to the heart?
coronary artery
which chamber the heart does deoxygenated blood flow in from the body?
right atrium
which chamber the heart does deoxygenated blood flow in from the right atrium?
right ventricle
which chamber the heart does oxygenated blood flow in from the lungs?
left atrium
which chamber the heart does oxygenated blood flow in from the left atrium?
left ventricle
what do the atrioventricular valves do?
prevent blood from flowing back into the atria
where are the atrioventricular valves located?
between the atria and ventricles
where are the semi-lunar valves located?
between the ventricles and blood vessel
what do the semi-lunar valves do?
prevent the back flow of blood between the ventricles and blood vessel
what are the stages of cardiac cycle?
atrial contraction
ventricular contraction
relaxation
repeat
what is atrial contraction?
when the atria contracts and due to a pressure increase, the blood flows down into the ventricles
what is ventricular contraction?
when the ventricle contracts and due to a pressure increase, the blood flows up into the blood vessels
what are arterioles?
smaller artery vessels
how do arterioles control the direction of blood?
contraction and relaxation of the walls
what is the structure of an artery?
thick muscle layer
contains elastic fibres
folded endothelium
what blood vessel carries blood away from the heart to the organs?
arteries
what is the structure of a vein?
wide lumen
thin muscle wall
valves
what blood vessel carries blood back to the heart?
veins
why do veins have valves?
to ensure the deoxygenated blood reaches the heart
why do veins have a wide lumen?
so the blood flows at a lower pressure
where are capillaries located?
close to the cells
why is the short diffusion distance between capillaries and the cells useful?
exchange between the blood and cells is rapid
why are capillary beds useful?
they have a large surface area for diffusion
what part of the capillary structure makes them useful for exchange?
muscle walls are one cell thick
how do substances move into the tissue fluid from the capillaries?
pressure filtration
what type of pressure is at the start of the capillary bed?
high
what is pressure filtration?
when the fluid in the capillaries flows down the pressure gradient into the surrounding space
what does tissue fluid do?
substances in fluid can be transported to the cells
when does the tissue fluid return the capillary?
when the pressure in the capillary is lower than the tissue fluid
where does the excess tissue fluid go?
the lymphatic system
what is an atheroma?
the deposition of materials in the arteries causing a blockage
what happens when white blood cells are deposited into the arteries?
a fibrous plaque will form
why do atheromas increase blood pressure?
they make the narrow lumen of the arteries even more narrow
what is an aneurysm?
when an atheroma increases the blood pressure causing the artery wall to swell
what is thrombosis?
when an artery bursts and platelets accumulate and form a clot
why is a thrombus dangerous?
they block the flow of blood in the artery
what are the risk factors of contracting cardiovascular disease?
high blood pressure
smoking
diet
what is the structure of the xylem?
a long tubes of vessel elements
are the cells in the xylem alive or dead?
dead
how does the xylem’s structure allow for a continuous tube of water to flow though?
the vessel elements have no cell walls
how is lignin important in xylem cells?
allows for it to be waterproof
provide structural support
what is transpiration?
when some of the water produced in photosynthesis evaporates out of the stomata
how is tension created in the xylem?
transpiration
which direction does the tension in the xylem pull the water?
upwards - to the leaves
how does cohesion pull the water up the xylem?
the water molecules are stuck together so when one molecule is pulled up, it pulls up those around it due to the hydrogen bonds
what does the combination of tension and cohesion in the xylem allow for?
water to be pulled upwards to replace that lost in transpiration
why does water enter the roots via osmosis?
the roots have a lower water potential due to water being pulled upwards
what are the four stages of the cohesion tension theory?
transpiration
tension
cohesion
diffusion into the roots
what piece of equipment is used to investigate the transpiration rate?
potometer
why when using a potometer should the plant be cut underwater?
to ensure no air enters the system
what is the structure of the phloem?
sieve tube elements
companion cells
sieve plates
what is the structure of the sieve tube elements?
living cells made of cellulose containing the cytoplasm and a nucleus
how are the companion cells and sieve tube elements connected?
plasmodesmata - allows them to share a cytoplasm
what are sieve plates?
plates with large pores which allow sap to move through the sieve tube elements
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