topic 7 Flashcards
describe the first stage of aerobic respiration
stage 1 - glycolysis
phosphorylation - the glucose is PHOSPHORYLATED by adding 2 PHOSPHATES from 2 ATPs, to form HEXOSE PHOSPHATE
the hexose phosphate splits using water (HYDROLOYSIS) to form 2 molecules of TRIOSE PHOSPHATE and 2 ADPs
oxidation - the ADP comes and picks up the phosphate (from the triode phosphate) to form 2 moles of ATP
this molecule is then OXIDISED (loses hydrogen) form two molecules of PYRUVATE
the co enzyme NAD (hydrogen carrier) collects the hydrogen ions forming NADH x2
products
pyruvate x2, NADH x2, ATP x2
describe the second stage of aerobic respiration
stage 2 - the link reaction occurs in the matrix of the mitochondria
the pyruvate molecule is DECARBOXYLATED (removes hydrogen) to form CO2 x2
the pyruvate is then OXIDISED (removes hydrogen) to form NADH x2
the co enzyme CO ENZYME A is then added to the molecule to form ACETYL CO ENZYME A
no ATP is produced in this process
products
acetyl co enzyme a x2
CO2 x2
NAPH x2
what is the third stage of aerobic respiration
stage 3 - Krebs cycle - occurs ij the matrix of the mitochondria
the acetyl co enzyme is combined with a 4 carbon sugar to form a 6 carbon molecule CITRATE
the CoA is then released to go back to the link reaction to be used again
the six carbon molecule loses a hydrogen to form NADH
the six carbon molecule is DECARBOXYLATED loses CO2 to form a 5 carbon molecule
the 5 carbon molecule loses 3 hydrogens to form 2x NADH and 1x FADH
the 5 carbon molecule is then DECARBOXYLATED removing a carbon to form CO2
this forms a 4 carbon molecule OXALOACETATE which will then be used again to combine with the acetyl co enzyme A
what is the final stage of aerobic respiration
the electron transport chain- where oxidative phosphorylation ( where ATP is synthesised by chemosmosis in the electron transport chain)
the NADH x2 and FADH carry the hydrogen ions and electron to the electron transport chain (this occurs in the inner mitochondrial membrane)
electrons are carried from one electron carrier to another in a series of REDOX REACTIONS
the electron carrier which passes the electron on is OXIDISED na the electron accrued which receives the electron is REDUCED
the energy from these series of redox reaction is used to transport the hydrogen ions from the INNER to the INTERmembranal space ( through channel proteins
there s now a higher concentration of ions in the intermembranal space than the inner
the hydrogens then move back into the MITOCHONDRIAL MATRIX down the ELECTROCHEMICAL GRADIENT through the protein ATP SYNTHASE
these hydrogen ions and electrons then combine with oxygen to form WATER
describe aerobic respiration which occurs in humans
- glycolysis in aerobic respiration occurs to produce pyruvate
- LACTATE DEHYDROGENASE removes 2 hydrogens from NADH and adds them to the pyruvate to form LACTATE
aerobic respiration in plants and
- glycolysis occurs to produce pyruvate
- CO2 is removed from the pyruvate to produce ETHANAL
- ALCOHOL DEHYDROGENASE coverts the ethanal into ETHANOL by adding hydrogen taken from NADH
what happens to lactate after a period of time
after a period o ftim most of the lactate is transported to the LIVER, where a hydrogen is removed and it forms PYRUVATE
it can the be used again for the link, Krebs and etc reaction
outline the cardiac cycle
(normal electrical activity of the heart)
7.8 ii
- the SAN (the pacemaker) generates an electrical impulse that imitates the contraction of the heart muscles.
- this spreads through the atria causing atrial systole
- bundle of his splits into two branches
- it cannot spread directly to the ventricles due to the regions of the non conductive tissue
- the atrioventricular node AV is the only point that the impulses can pass through.
- a slight delay occurs before the ventricular systole to ensure that all the blood can leave the atria before another impulse is generated.
- the AVN then passes the electrical impulses through the bundle of his to the apex (base of the heart)
- this then spreads to the purkinyne fibres, then to the vertical walls and contract from the base upwards
describe the patterns seen in an ECG and why they are important
7.8 iii
p wave - atrial systole
pr interval - the time taken for impulses to be conducted from the SAN across the atria to the ventricle through the AVN
qrs complex- the wave of depolarisation resulting in contraction of the ventricles (ventricle systole)
t wave - depolarisation (recovery) in the ventricles during the hearts relaxation phase (diastole)
ECG traces can help to provide information about ABNORMAL HEARTBEATS, AREA OF DAMAGE and INADEQUATE BLOOD FLOW.
control of heart rate
- chemo receptors and pressure receptors will detect a stimuli in the blood. (chemoreceptors monitor the oxygen, carbon dioxide and pH levels of the 2.blood and the pressure receptors will monitor the blood pressure)
- electrical impulses will be generated from these receptors to the MEDULLA OBLONGATA along a sensory neuron.
- the cardiovascular control centre (medulla oblongata) will process the in formation and then send electrical impulses to the SAN along SYMPATHETIC or PARASYMPATHETIC neurones
- these neurones will release different neurotransmitters which determines whether the heart rate will speed up or slow down
parasympathetic neurones will be used to decrease heart rate (for the SAN to fire LESS electrical impulses)
sympathetic neurones will be used to increase heart rate (for the SAN to fire MORE electrical impulses)
acetylcholine is a neurotransmitter used to decrease heart rate
noradrenaline is a neurotransmitter used to increase heart rate
how do you work out the cardiac output
7.9 i
cardiac output = stroke volume x heart rate
units
cardiac output =
stroke volume = cm^3
heart rate =
describe inhaling (inspiration)
- the diaphragm contracts to move down and become flatter
- the external intercostal muscles contracts to raisee the ribs
- the volume of the chest cavity is increased
- the pressure in the chest cavity drops below the atmospheric pressure
- there is now a pressure gradient
- so more air is moved into the lungs
describe exhaling (exhaltion)
- the diaphragm relaxes and is pushed up
- the external intercostal muscles relaxes and the ribs fall
- the volume of the chest cavity decreases
- the pressure in the lungs increases above the atmospheric pressure
- there is now pressure gradient
- so more air is moved out of the lungs
define vital capacity and tidal volume
vital capacity - this is the maximum volume of air that can be moved by the lungs in one breath
tidal volume - this is the volume of air moved in and out with each breath, usually measured at rest
fast and slow twitch muscle s
slow twitch fibres are specialised of slow contractions, and are adapted for long periods of exercise, therefore do nota fatigue quickly. they contain many mitochondria and a lot of myoglobin (this is a protein which contains a haem group which can attach oxygen to it and therefore can be used to supply a lot of oxygen to the muscles)
fast twitch muscles are specialised for rapid relaxes of energy during intense exercise such as sprinting where the contractions are intense and short burst. fast twitch muscles have very few mitochondria but have high levels of GLYCOGEN ( tis is used as an energy store for glucose) and has high levels of creatine phosphate.
