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Biology 7&8 > Aerobic respiration, Homeostasis & Exercise > Flashcards

Aerobic respiration, Homeostasis & Exercise Flashcards

1
Q

Describe the overall reaction of aerobic respiration

A
  • A respiratory substance is broken down to release a large amount of energy
  • H2 combines with atmospheric O2 to produce H2O and CO2 is released is released as a waste product
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2
Q

Name the 4 main stages of aerobic respiration and where they occur

A

Glycolysis - cytoplasm
Link reaction - Mitochondria
Krebs cycle - Mitochondria
Oxidative phosphorylation - via electron transfer chain in the membrane of cristae

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3
Q

Outline the stages of glycolysis

A
  1. Glucose (6C) is converted to glucose phosphate (6C) and then fructose biphosphate (6C) (phosphofructosekinase and pump priming), 2 molecules of ATP are required to provide the 2 phosphates needed for the phosphorylation
  2. Two molecules of Glycerate 3-phopshate (3C) are made it loses 2 hydrogens to form two pyruvate ions (3C), H+ ions are collected by NAD forming two reduced NAD and dephosphorylation takes place
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4
Q

How many ATP are made during Glycolysis?

A

4 ATP molecules were produced but 2 were used to phosphorylate glucose, therefore there was a net gain of 2 ATP molecules

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5
Q

How does pyruvate from Glycolysis enter the mitchondria?

A

Active transport

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6
Q

What happens during the link reaction?

A
  1. Pyruvate is decarboxylated, one carbon atom is released as CO2
  2. NAD is reduced changing pyruvate into acetate
  3. Acetate is combined with CoA to form acetyl CoA
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7
Q

Outline the stages of the Krebs cycle

A
  1. Acetyl CoA (2C) combines with oxaloacetate (4C) to form Citrate (6C)
  2. Citrate is converted to a 5C molecule through decarboxylation where CO2 is removed aswell as dehydrogenation to produce reduced NAD from NAD+
  3. The 5C molecule is converted to a 4C molecule, decarboxylation and dehydrogenation occurs producing 1 molecule of reduced FAD and 2 of reduced NAD
  4. ATP is also produced, citrate has been regenerated to oxaloacetate
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8
Q

Outline the stages of oxidative phosphorylation

A
  1. Hydrogen atoms are donated by reduced NAD and FAD, hydrogen atoms split into protons and electrons
  2. Electrons pass through the ETC and release energy, the protons are transported by the energy released from the matrix to the intermembrane establishing a conc gradient
  3. The protons return to the matrix via facilitated diffusion through ATPsynthase, H2O is formed oxygen act as the final electron acceptor
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9
Q

How many ATP molecules can be made from one glucose molecule?

A

38

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10
Q

Define the term myogenic

A

The heart will beat without any external stimulus and it initiates depolarisation

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11
Q

Where is the sinoatrial node found (SAN)?

A

In the wall of the right atrium

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12
Q

Describe the stages of the cardiac cycle

A
  1. The SAN initiates a wave of depolarisation that causes the atria to contract
  2. The depolarisation is sent to the atrioventricular node (AVN) which is a region of conducting tissue
  3. After a slight delay the AVN is stimulated and it passes the impulse to the bundle of His where it divides into 2 fibres called Purkyne tissue
  4. The purkyne fibres spread around the ventricles and initiates the depolarisation of the ventricles from the apex upwards, forcing the blood out
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13
Q

Describe the roles of different waves in an ECG of a healthy heart

A

P wave= depolarisation of the atria resulting in atrial systole
QRS complex= depolarisation of the ventricles resulting in ventricular systole
T= repolarisation of the ventricles resulting is ventricular diastole
U= scientists are still unsure, possibly repolarisation of the Purkyne fibres

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14
Q

Define Tachycardia

A

Too fast heartbeat <100 bpm

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15
Q

Define Bradycardia

A

When the heart beats too slow >60 bpm

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16
Q

What is an Ectopic heartbeat?

A

An early heartbeat followed by a pause

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17
Q

Define Fibrillation

A

An irregular heartbeat

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18
Q

What controls heart and ventilation rate?

A

Autonomic nervous system

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19
Q

What does an increased breathing and heart rate do?

A

Increased breathing rate - to obtain more oxygen and to get rid of more CO2
Increased heart rate - to deliver oxygen to the muscles faster and remove extra CO2 produced by increased rate or respiration

20
Q

What is the role of the Medulla Oblongata?

A

Controls breathing rate

21
Q

What are the 2 ventilation centres found in the medulla oblongata?

A

The inspiratory and expiratory centre

22
Q

What does the inspiratory centre do?

A
  • Sends nerve impulses to the intercostal muscles and diaphragm muscles to make them contract
  • This increases lung volume and decreases its pressure
23
Q

How are stretch receptors in the lungs stimulated?

A

Stimulated when inflated with air

24
Q

What does the expiratory centre do?

A
  • It sends nerve impulses to the intercostal and diaphragm muscles, these muscles will relax and cause the volume of the chest to decrease and increasing the air pressure in the lungs
  • As the lungs deflate, the stretch receptors become inactive
25
How does exercise trigger an increase in breathing rate by decreasing blood pH?
1. During exercise, the level of CO2 in the blood increases decreasing pH levels 2. There are chemoreceptors in the medulla oblongata, aortic bodies and carotid bodies that are sensitive to pH changes 3. If chemoreceptors detect a decrease in blood pH they send nerve impulses to the MO which send more impulses to the intercostal muscles and diaphragm 4. This causes gaseous gas exchange to speed up
26
What is the sympathetic nervous system?
Gets the body ready for action, its the 'fight or flight' system helping to increase the heart rate during exercise
27
Whats the parasympathetic nervous system?
Calms the body down helping to decrease heart rate
28
What receptors detect changes in blood pressure?
Baroreceptors
29
How does the body respond to high blood pressure?
1. Baroreceptors detect high bp 2. Impulses sent along cardiovascular control centre sending impulses to parasympathetic neurones, secreting acetlycholine binding to receptors on SAN 3. SAN fires less impulses to slow heart rate and reduce bp
30
How does the body respond to low blood pressure?
1. Baroreceptors detect low bp 2. Impulses sent along cardiovascular control centre sending impulses sympathetic neurones, secreting noradrenaline binding to receptors on SAN 3. SAN fires more impulses to increase heart rate and bp
31
How does the body respond to high pH levels?
1. Chemoreceptors detect chemical changes 2. Impulses sent along cardiovascular control centre sending impulses to the parasympathetic neurones, secreting acetlycholine which binds to receptors on SAN 3. SAN fires less impulses
32
How does the body respond to low pH levels?
1. Chemoreceptors detect chemical changes 2. Impulses sent along cardiovascular control centre sending impulses to the sympathetic neurones, secreting noradrenaline which binds to receptors on SAN 3. SAN fires more impulses
33
What is the equation for working out cardiac output?
Cardiac output=heart rate*stroke volume
34
What is tidal volume?
Volume of air that is breathed in or out during normal breathing
35
What is breathing rate?
Number of breaths taken in 1 minute
36
Give 3 reasons why exercise is good?
1. Improves life expectancy 2. Protects against heart disease, stroke and high blood pressure 3. Improves cognitive function
37
What are the 4 ways that exercise may benefit immunity?
1. Physical activity may flush bacteria out the lungs 2. Causes changes in antibodies and white blood cells 3. Brief rise in body temp, preventing bacteria growth 4. Slows down the release of stress related hormones
38
What are the effects of moderate exercise on immunity?
1. Increases number and activity of lymphocytes 2. Provide non specific immunity 3. Produce perforin which attacks the cell membranes of pathogens by making pores in it
39
What are the effects of vigorous exercise on immunity?
1. Reduces natural killer cells, phagocytes, B cells and T cells - Fewer T cells means less cytokine produced so less lymphocytes/antibodies activated 2. Suppresses specific immune response 3. Stress of training could release cortisol and adrenaline further suppressing the immune system 4. Muscle damage may lead to an inflammatory response using up 'valuable' lymphocytes
40
What effect does a high body temperature have on enzymes?
- Enzymes would denature due to an increase of kinetic energy which would result in the break of hydrogen bonds - The active site will change shape and no longer be complementary - Enzyme-substrate complex won't form so enzyme will not catalyse
41
What are the cooling mechanisms that regulates body temperature?
- Vasodilation to increase heat loss by which is done by supplying the capillaries with a greater volume of blood - Sweating cools the skin by evaporation - Flattening of hair erector pili muscles stopping them from forming an insulating layer
42
What are the warming mechanisms that regulates body temperature?
- Vasoconstriction to decrease heat loss by supplying the capillaries with a smaller volume of blood, instead blood is diverted to shunt vessels - Boosting metabolic rate - Shivering is a reflex action which contract in a rapid and regular manner - Erection of hair erector pili muscles to form an insulating layer - Less sweating
43
What are the affects of there not being enough oxygen in respiration?
1. No final acceptor of electrons 2. ETC stops functioning 3. No more ATP produced via oxidative phosphorylation 4. Reduced NAD and FAD aren't oxidised 5. No oxidised NAD and FAD available
44
How can lactate be produced from the link reaction?
1. Reduced NAD transfers hydrogen to pyruvate to form lactate 2. NAD can now be reused in glycolysis 3. Pyruvate is reduced to lactate by enzyme lactate dehydrogenase
45
What 2 things might happen after lactate is produced and is built up in cells?
1. It can be oxidised back to pyruvate 2. Can be converted into glucose by the liver cells
46
What is oxygen debt?
The oxidation of lactate back to pyruvate requires extra oxygen - which is known as the oxygen debt

Biology 7&8 (4 decks)

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