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A Level Biology (Salters-Nuttfield SNAB) > Topic 7: Run for your Life > Flashcards

Topic 7: Run for your Life Flashcards

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1
Q

What are ligaments?

A

Tough, elastic connective tissue, which attach bone to bone. They provide stability

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2
Q

What are tendons?

A

Touch elastic connective tissue comprised of collagen and fibres which attach muscle to bone.

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3
Q

What are antagonistic muscle pairs?

A

A pair of muscles that work together to produce a movement. As muscles are only capable of contracting or pulling they operate in pairs to produce movement: when one of the muscles contracts (extensors) and the other relaxes (flexors)

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4
Q

What is the role of an extensor in muscle movement?

A

In an antagonist pair the muscle that contracts and shortens is the extensor.It is known as the agonist.

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5
Q

What is the role of the flexor in muscle movement?

A

In an antagonistic pair muscle that relaxes and lengthens is the flexor. It is known as the antagonist.

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6
Q

What is cartilage?

A

This is tough, elastic tissue found in joints between bones. It is responsible for protecting the skeletal systems acting as shock absorbers.

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7
Q

What is a skeletal muscle?

A

Skeletal muscles are the muscles in the body that are attached to the skeleton. They are made up of muscle fibres.

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8
Q

What is sarcolemma?

A

This is the cell membrane that surrounds muscle fibres. They have deep tube like projections that’s fold in forms it’s outer surface known as T - tubules, which help disperse impulses to different parts of the muscle fibres.

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9
Q

What is sarcoplasm?

A

This is the cytoplasm found in muscle fibres. It gives the cell shape and contains mitochondria and myofibrils that perform cell reactions.

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10
Q

What is the sarcoplasmic reticulum?

A

This is a double membrane organelle which act like the endoplasmic reticulum. The membrane of the SR contains protein pumps that transport and release calcium ions for muscle contraction.

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11
Q

What is a myofibril?

A

Long cylindrical organelle in muscle fibres located in the sarcoplasm. They consist of sarcomeres (monomer unit)

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12
Q

What are sarcomeres?

A

These are the monomer units that make up microfibrils. They contain myosin filaments, actin filament, tropomyosin and troponin.

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13
Q

What are myosin filaments?

A

These are thick myofilaments made of the protein myosin. They have hinged globular heads that contain actin binding sites and ATL binding sites. They enable muscle contraction.

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14
Q

What are actin filaments?

A

These are thin myofilaments made up of the protein actin. They have actin-myosin binding sites for the hinged globular myosin heads.

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15
Q

What is tropomyosin?

A

This is a protein that is found between thin actin filaments. They bind to actin-myosin binding sites preventing muscle contraction when the muscles if at rest.

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16
Q

What is troponin?

A

This is a protein that is found between thin actin filaments. Troponin holds tropomyosin in place when tropomyosin binds to the actin-myosin binding sites.

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17
Q

What are the two types of muscle fibres?

A
  • fast twitch
  • slow twitch
    Humans muscles are made up of both fibre and each muscle have different proportions of each depending in their function.
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18
Q

What are fast twitch muscle fibres?

A

Fast twitch muscles connect rapidly, with the myosin heads bind and unbind from the the actin binding sites five times faster than slow twitch muscle fibres. They are suited to short bursts of high intensity activity as they fatigue quickly due to lactate production.
E.g. human eyelids

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19
Q

What are slow twitch muscle fibres?

A

Slow twitch muscle fibres contract more slowly and are suited to sustained activity (walking). They fatigue less quickly due to less lactate production making them good for endurance.
E.g. Human back muscles

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20
Q

What are the main characteristics of slow twitch muscle fibres?

A
  • rely on aerobic respiration for ATP
  • contain many capillaries (increasing blood flow)
  • contain many many mitochondria
  • low glycogen content
  • they are redder as contain high amounts of myoglobin
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21
Q

What are the main characteristics of fast twitch muscles?

A
  • fewer capillaries (reduced blood flow)
  • white in coconut as don’t have much myoglobin
  • ATP supplied from anaerobic respiration
  • fewer smaller mitochondria
  • large stores of calcium ions
  • large amount of glycogen
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22
Q

What is the structure of thick muscle filaments?

A

The thick filaments within a myofibril are made up if myosin molecule
- these are fibrous proteins with a globular head
- fibrous part of the myosin molecule anchors the molecule into the thick filament

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23
Q

What is the structures of thin muscle filaments?

A

The thin filaments are made up of actin molecules
- they are globular protein molecules
- they link together to form a chain , with two chains that twist together to form one thin filaments
- tropomyosin is twisted around the two actin chains
- troponin is attached to the chains as regular intervals

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24
Q

What is the process of muscle contractions?

A
  1. Motor neurones transmit impulses from the CNS to the effector cells (muscle cells). This creates an action potential between a motor neurone and muscle fibre
  2. Calcium ions are released from the sarcoplasmic reticulum (SR)
  3. The calcium ions bind to troponin molecules on actin filament stimulating them to change shape
  4. This causes troponin and tropomyosin proteins to change position on actin filaments exposing the myosin binding sites.
  5. The globular heads of the myosin molecules bind with these sites, forming cross-bridges between the two types of filament.
  6. The formation of the cross bridges causes the myosin heads to nod forward pulling the actin filament towards the centre of the sarcomeres (it shortens) and ADP and Pi are released and muscle is contracted.
  7. ATP binds to ATP binding sites on the hinged globular myosin heads. This breaks down the actin myosin cross bridges causing the myosin to detach form the actin.
  8. The enzyme ATPase hydrolyses ATP into ADP and Pi causing the the myosin heads to move back to their original positions.
  9. As long as troponin and tropomyosin are not blocking the Muslims binding sites and the muscles has a supply of ATP, this process repeats until the muscle is fully contracted.
  10. Once muscle contractions stop, calcium ions leave their binding sites in the troponin molecule and actively transport back to SR.
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25
Q

What is aerobic respiration?

A

The process of breaking down a respiratory substrate in order to produce ATP using oxygen, releasing carbon dioxide as a waste product.

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26
Q

Where does aerobic respiration take place?

A

It occurs in the cytoplasm and mitochondria of the cell.

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27
Q

What is the aerobic respiration equation?

A

C6H12O6 + 6O2 —> 6CO2 + 6H2O

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28
Q

What are the four stages in aerobic respiration?

A
  • glycolysis (occurs in cytoplasm)
  • the links reaction (mitochondrial matrix)
  • the Krebs cycle (mitochondrial matrix)
  • oxidative phosphorylation (inner membrane of mitochondria)
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29
Q

What are the main coenzymes required during respiration?

A
  • NAD and FAD are responsible for the transfers of hydrogen between molecules (reducing or oxidising a molecule)
  • coenzyme A is responsible for the transfer of acetate from one molecule to another
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30
Q

What is the structure of the mitochondria?

A
  • outer membrane (smooth, permeable to several molecules)
  • inner membrane (folds called cristae, site of electron transport chain and location of ATP synthase enzymes)
  • inter-membrane space
  • matrix
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31
Q

What is glycolysis?

A

It is the process by which a respiratory substrate glucose is broken down into 2 pyruvate molecules. Glycolysis is the first stage of respiration, it does not require any oxygen so happens in both aerobic and anaerobic respiration.

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32
Q

What is the process of glycolysis?

A
  1. The 6 carbon glucose (hexose sugar) goes through phosphorylation where two ATPs are used to convert glucose into two molecules of triose phosphate (3C) and produced two ADP + Pi
  2. The triose phosphates are oxidised loosing 2 hydrogen atoms and producing two molecules of pyruvate (3C) are formed. NAD collects the hydrogen forming two NADH.
  3. ATPase synthesis the phosphorylation of ADP + Pi forming 4 molecules of ATP.
    Net gain of of ATP = 2
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33
Q

What is ATP?

A

ATP is a molecule that carry’s energy around the body, and it created by the phosphorylation of ADP.

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34
Q

How is ATP energy formed?

A

It is formed from the phosphorylation of ADP. This is the proccess by which energy is released form respiration is used to combine ADP and an inorganic phosphate (Pi). It is catalyst by the enzyme ATPsynathse (found in inner membrane)
ADP + Pi + energy = ATP + H20

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35
Q

Describe the functions of specific intercellular enzymes in aerobic respiration?

A
  • enzymes are proteins with complex tertiary and quaternary structures which are complementary to specific substrates
  • each step in aerobic respiration is controlled by these enzymes, as they convert each intermediate substrate into the next acting as a biological catalyst.
  • they act as a biological catalyst as they reduce the activation energy for biochemical reactions by forming enzyme substrate complex’s.
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36
Q

What is the link reaction?

A

The links reaction is the second step in aerobic respiration that occurs in the motrichindrial matrix. It it’s the proccess by which 2 molecules of pyruvate (3C) produce 2 molecules of acetat (2C) which combine wiht coenzyme A (acetyl CoA). This produces 2 NADH with no net gain of ATP.

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37
Q

What is the process of the links reaction?

A
  1. Pyruvate form glycolysis will enter the mitochondrial matrix via active transport.
  2. The pyruvate is oxidised and decarboxylated (hydrogen and carbon removed) by enzymes to produce acetate (2C)
  3. The carbon is removed through CO2 and hydrogen is collected by NAD to form NADH
  4. Acetate combines with coenzyme A to from acetyl coenzyme A (Acetly CoA)
    This will occur twice for each molecule of glucose. (Glucose produces two pyruvate s in glycolysis)
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38
Q

What does the links reaction produce?

A
  • 2 molecules of acetyl CoA
  • 2 molecules of CO2
  • 2 molecules of reduced NAD (NADH)
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39
Q

What is the Krebs cycle?

A

The Krebs cycle is the third steps of aerobic respiration which takes a place in the mitochondrial matrix. It consists of a series of enzyme - controlled reactions in a recurring cycle.

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40
Q

What do the steps of the Krebs cycle?

A
  1. Two acetyl CoA enters the circular pathways from the Links reaction.
  2. Each molecule of acetly CoA combines wiht oxaloacetate (4C) producing citrate (6C).
  3. Each molecule of citrate (6C) is decarboxylated and dehydrogenated to produce a 5 carbon compounds. This releases CO2 and NADH that are to be used in oxidative phosphorylation
    4.The immediate 5 Carbon compound then dehydrogenated and decarboxylated producing a molecule of oxaloacetate (4C) which is then recycled in the cycle. This produces CO2 and NADH, and ADP the goes through phosphorylation forming a molecule of ATP catalysed by ATPsynathase
  4. Other intermediate reactions produce NADH and FADH2.
    7, oxaloacetate is then recycled back into the Krebs cycle.
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41
Q

What are the products of the Krebs cycle?

A

As there are two molecules of pyruvate the Krebs cycle will happen twice producing
- 2 ATP
- six NADH
- two FADH2
- Four CO2

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42
Q

What is oxidative phosphorylation?

A

It is the last stage of aerobic respiration, which takes place in the inner mitrochindrial membrane and results in the production of many molecules of ATP and the production of water.

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43
Q

What is the chemiosmotic theory?

A

The models states that energy created from electrons passing through an electron transport chain in the membrane is used to pump (H+) against the concentration gradient into the inter membrane space via active transport. This creates a concentration gradient and H+ move back into the matrix by facilitated diffusion through channel enzyme ATP synthase. The energy is harnesses and is used in the phosphorylation of ADP into ATP BY ATPsynthase.

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44
Q

What is the process of oxidative phosphorylation?

A
  1. Hydrogen atoms are donated by reduced NAD and reduced FADH from the Krebs cycle.
  2. Hydrogen ion spilt into protons and release an electron
  3. The electrons enter the electron transport chain and release energy as they move through electron transport chain
  4. Energy released is used to transport protons across inner mitochondrial membrane form the matrix into inter-membrane space.
  5. A concentration gradient of protons is established between between inter-membrane space and matrix
  6. Protons return to matrix via facilitated diffusion through channel enzyme ATP synthase
  7. The movement of protons down their concentration gradient provides energy for ATP synthesis (ADP + Pi)
  8. Oxygen acts as the ‘final electron acceptor’ and combines with protons and electrons at the end of the electron transport chain to form water
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45
Q

What is an electron transport chain?

A

An ETC is made up of a series of membrane proteins that sit close together to allow electrons to pass from carrier to carrier.

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46
Q

How many ATP molecules are created at the end of aerobic respiration?

A

38

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47
Q

What is anaerobic respiration?

A

This is when respiration occurs without oxygen, producing much less ATP. It realises a small prop of energy and also produces lactic acid.

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48
Q

Why can’t aerobic respiration happen without oxygen?

A
  • no final acceptor of electrons (oxygen) form the electron transport chain meaning it stops functioning
  • no more ATP is then produced from oxidative phosphorylation
  • no oxidised NAD and FAD so Kerbs and Links reaction stops
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49
Q

How can organism respire anaerobically?

A
  • cells able to oxidise the reduced NAD produced during glycolysis so it can used for further hydrogen transport
  • this means glycolysis can continue and small amounts of ATP are still produced
  • other organisms use lactate fermentation. (Micro-organisms and mammalian muscles)
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50
Q

What is lactate fermentation?

A
  1. The reduced NAD (NADH) transfers the hydrogen to pyruvate to form lactate catalyst by enzyme lactate dehydrogenase.
  2. The NAD can be reused in glycolysis
  3. Small amounts of ATP is produced
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51
Q

How is lactate processed?

A

Lactate (lactic acid) will build up in the surrounding tissues and muscle before eventually entering the bloodstream. It is then transported to the liver where it is either
- oxidised back into pyruvate (channeled back into Kerbs cycle)
- converted into glucose (used in respiration)

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52
Q

What is needed for lactate to be processed?

A

It needs an oxygen dept (extra oxygen). Gained by deeper and faster breaths.

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53
Q

Why can the heart be described as myogenic?

A

It’s myogenic as the heart will beta without any external stimulus. It’s intrinsic rhythm means the heart beat at around 60 bpm.

54
Q

What is the the sinoatrial node?

A

The sinoatrial node (SAN) is a group of cells in the wall of the right atrium.

55
Q

What’s the role of the SAN?

A

it initiates a wave of depolarisation that causes the atria to contract.

56
Q

What is the atrioventricular node (AVN)?

A

A region of connecting tissue between the atria and ventricles. It is stimulates and passes the stimulation along the bundle of His.

57
Q

What is the bundle of His?

A

The bundle of His is a collection of conducting tissues in the septum’s of the heart. It divided into two connecting fibres (Purkyne tissue) and carries the wave of excitation along them.

58
Q

What are the Purkyne fibres?

A

These are fibres that spread around the ventricle and initiates the depolarisation of the ventricles from the apex of the heart, causing the to contract upwards.

59
Q

How does the heart coordinate a heart beat (stages)?

A
  1. Sinoatrial node sends out a wave of excitation
  2. This depolarisation causes the atria to contract
  3. After a slight deltas the Atrioventricular node is stimulated and passes stimulation along bundle of His.
  4. Purkyne tissues conduct the wave of excitation imitating depolarisation of the ventricles from the apex
  5. Ventricles contract from bottom upwards losing blood out of ventricles into pulmonary artery and aorta.
60
Q

What is electrocardiography?

A

Electrocardiography can be used to monitor and investigate the electrical activity of the heart. Electrodes that are capable of detecting electric,a signals are placed in the skin producing an electrocardiogram (ECG).

61
Q

What does as ECG show?

A

It’s shows the number of distinctive electrical waves produced by the activity of the heart. The bigger the wave the greater the electrical activity passing though the heart, and stronger the contractions.
P wave, QRS complex, T wave and U wave

62
Q

What is the P wave on an ECG?

A

The P wave is the first wave caused by the depolarisation of the atria, resulting in atrial systole (contraction).

63
Q

What is the QRS complex on an ECG?

A

Caused by the depolarisation of the ventricles, which results in ventricular systole (contraction). It is the largest wave as ventricle have the largest muscle mass.

64
Q

What is the T wave on an ECG?

A

Causes by the repolarisation of the ventricles (ventricular relaxation/diastole)

65
Q

What is the u-wave on a ECG?

A

The cause of the U wave is still undetermined, though scientist think it’s the repolarisarion of the Purkyne fibres.

66
Q

What would the ECG look like on someone with Tachycardia?

A

This is when the heart beats to fast. The ECG will shows a resting heart rate of over 100 bpm won’t wave peaks very close together.

67
Q

What would the ECG look like on someone with Bradycardia?

A

This is when an individuals heart beat to slow, the ECG will show a resting heart rate below 60 bpm. Waves will be very far apart.

68
Q

What would the ECG look like on someone with an Ectopic heartbeat?

A

This conditions is caused by an early heartbeat followed by a pause. Due to an early contraction of either the atria or ventricle.

69
Q

What is cardiac output?

A

Cardiac output is the volume of blood that is pumped out by the heart per unit of time (per minute)

70
Q

What effect cardiac output?

A
  • individuals who are fitter have higher cardiac outputs due to thicker and stronger ventricular muscles
  • if an individual is exercising so blood supply can match the increased metabolic demand of the cells.
71
Q

What is stroke volume?

A

The volume of blood pumped out of the left ventricle during one cardiac cycle.

72
Q

What is heart rate?

A

The number of times a heart beats per minute.

73
Q

How do you calculate cardiac output?

A

Cardiac output (cm3 min-1) = heart rate (bpm) x stroke volume(cm3)

74
Q

What is the medulla oblongata?

A

This is the cardiovascular control centre which unconsciously controls the heart rate by controlling the rate at which the sinoatrial node generates electrical impulses causing the atria to contract.

75
Q

What stimulates changes in the heart rate?

A

Baroreceptors (found in aortic and carotid bodies)
Chemoreceptors (found in medualla oblongata, aortic and carotid bodies)
These are stimulated by changes in carbon dioxide and oxygen blood levels and blood pH.

76
Q

What happen when a stimulus stimulate the heart rate receptors?

A
  1. The receptors will simulate an electrical impulse to the medulla oblongata.
  2. The cardiovascular control in medulla oblongata will reposed by sending electrical impulses to SAN along sympathetic or parasympathetic neurones.
77
Q

What are sympathetic neurones?

A

This will increase the rate at which the SAN generates electrical impulses, speeding up the heart rate. E.g. during exercise/fight or flight

78
Q

What are the parasympathetic neurones?

A

This will decrease the rate at which the SAN generate electrical impulses thus slowing down the heart rate. (Rest)

79
Q

What changes the heart rate?

A
  • high or low blood pressure
  • high blood O2, low CO2 and high pH levels
  • low blood O2, high CO2 and high Ph levels
80
Q

How does high blood pressure change heart rate?

A
  1. High blood pressure is detected by baroreceptors
  2. Impulse send along parasympathetic neurones secreting acetylcholine
  3. Acetylcholine binds to receptors on SANs causing it to fire less frequently
  4. Heart rate slows and blood pressure decreases
81
Q

How does low blood pressure change heart rate?

A
  1. High blood pressure is detected by baroreceptors
  2. Impulse send along sympathetic neurones secreting noradrenaline
  3. Noradrenaline binds to receptors on SANs causing it to fire more frequently
  4. Heart rate increases and blood pressure increases
82
Q

How does high blood O2, low CO2 and pH level affect heart rate?

A
  1. Detected by chemoreceptors
  2. Send impulse along parasympathetic neurones screwing acetylcholine.
  3. Binds to receptors on SANs causing to fire less frequently
  4. Heart rates low down and returns O2/CO2/pH to normal levels
83
Q

How does low blood O2, high CO2 and low Ph (during exercise) affect heart rate?

A
  1. High blood pressure is detected by chemoreceptors
  2. Impulse send along sympathetic neurones secreting noradrenaline
  3. Noradrenaline binds to receptors on SANs causing it to fire more frequently
  4. Heart rates speed up and O2/CO2/pH levels return to normal.
84
Q

How does the body respond to exercise?

A

During exercise muscle contraction occur more frequently and require more energy. Rate of aerobic respiration increase amending cells require more oxygen
- increased rate and depth of breathing (increase if amount of O2 entering lungs and bloodstream)
- increase heart rate (transporting oxygen and glucose faster)

85
Q

What controls breathing rate?

A

Breathing rate is controlled by the ventilation centres in the medulla oblongata.
Inspiratory centre (controls movement of air into the lungs)
Expiratory centre (controls movement of air out of the lungs)

86
Q

How does the inspiratory centre effect breathing rate?

A
  1. Send nerve impulses along motor neurone to intercostal and diaphragm muscles
  2. Muscles contract causing volume of the chest to increase
  3. Lowers air pressure in the lungs to slightly below atmospheric pressure
  4. Impulse sent to expiratory centre to inhibit its action
  5. Air will flow into the lungs
87
Q

How does the expiratory centre control breathing rate?

A
  1. Sends nerve impulses to intercostal and diaphragm muscles
  2. Muscle relax causing volume of chest to decrease
  3. Higher pressure in lungs causes air to flow out.
88
Q

What’s the processes of inhalation?

A
  1. External intercostal muscles contract
  2. Rib cage moves up and out
  3. Diaphragm contracts and flattens
  4. Volume of thorax increases
  5. Pressure inside thorax decreases
  6. Air is drawn in
89
Q

What is the process of exhalation?

A
  1. External intercostal muscles relax
  2. Rib cage moves down and in
  3. Diaphragm relaxes and becomes dome shaped
  4. Volume of thorax decreases
  5. Pressure inside thorax increases
  6. Air is forced out
90
Q

How does exercise affect the blood pH?

A

Increased rate of respiration during exercise increased the rate of dissolved CO2 in the blood to form carbonic acid.
1. The acid dissociates into hydrogen ions and hydrogencarbonate ions
2. Increased [H+] makes the blood more acidic decreasing pH, this change in detected by chemoreceptors

91
Q

What is the definition of homeostasis?

A

This is the maintenance of a stable internal environment through physiological mechanisms in order to maintain proper cell, tissue, organ, organ system functions

92
Q

What is positive feedback?

A

This is when physiological mechanisms work to amplify/enhance an original change, deviating further from the normal range.
E.g. dilation if the cervix during labour.

93
Q

What is negative feedback?

A

This is when physiological mechanisms work to eliminate an original change back toward the normal level.

94
Q

How is dilation of the cervix an example of positive feedback?

A

Cervix stretches as baby pushed against it, stretch receptors in the cervix are stimulated and send impulses to the brain. Pituitary gland is stimulate to release oxytocin increasing intensity of uterine contractions pushing the bay further down birth canal stretching cervix further.

95
Q

Why is homeostasis so important?

A

It important in maintaining the body in a state of dynamic equilibrium during exercise by regulating factors such as pH, temperature and blood glucose. It helps to maintain enzyme activity.

96
Q

What is the control mechanism for maintaining body temperature?

A

Maintenance of the constant internal body temperature is known as thermoregulation. It involve both cooing and warming mechanisms.

97
Q

What are the main cooling mechanisms of the thermoregulation?

A
  • vasodilation of the blood vessels that supply skin capillaries (more heat evaporation)
  • sweating (heat lost through evaporation)
  • flattering of hair
98
Q

How does vasodilation act as a cooling mechanism?

A

The capillaries nearer the skin is supplied with a greater volume of blood with shut contracting to decrease blood flow to deeper arteries, which then loses heat to the environment via radiation.

99
Q

How does sweating act as a cooling mechanism?

A

Sweat is secreted by sweat glands, this cools the skin as the sweat absorbs heat energy form the blood which converts liquid water into water vapour. Taking heat from the body.

100
Q

How does flaccid hairs act as a cooling mechanism?

A

The hair erector pile muscles in the skin relax, causing the hairs to lie flat. This prevents then from forming an insulating layer of trapped air and allows air circulate over skin, heat can therefor leave by radiation.

101
Q

What are main warming mechanisms of thermoregulation?

A
  • Vasoconstriction of blood vessels
  • Boosting metabolic rate
  • shivering
  • erection of hairs
  • less sweating
102
Q

How does vasoconstriction act as a warming mechanism?

A

This is when arteries contract and the shunt vessels dilate ignorer to decrease the volume of blood through the vessels. As a less heat will be lost through radiation.

103
Q

How does shivering act as warming mechanism?

A

Shivering is a reflex action, were the the muscles will involuntarily contract in spams generating heat.

104
Q

How does the erection of hairs act as a warming mechanism?

A

The hair erector pili muscles in skin contract, causing hairs to stand on end. This forms an insulating layer over the skins surface by trapping the air between the hairs and stops heat from being lost by radiation. (Heat retention)

105
Q

How does boosting the body’s metabolic rate act as a warming mechanism?

A
  • most metabolic reactions in the body are exothermic providing warmth to the body
  • in cold environments the hormone thyroxine increases the basal metabolic rate
  • adrenaline may also be releases to speed up metabolic rate.
106
Q

What is the role of the hypothalamus is thermoregulation?

A

Mammals detect external temperatures via thermoreceptors in skin and mucous membrane. The receptors decent the hot or cold temperatures, and communicate it with the hypothalamus along sensory neurones, in turn the hypothalamus send impulses along motor neurones to effectors to bring about a physiological response.
It also monitors the temperature of the blood flowing through it

107
Q

How does hormones control physiological mechanisms inside the cell?

A

hormones the can cross the cell surface membrane are able to enter the nucleus and bind to transcription factors inside the cell.

108
Q

What is the process of hormonal regulation of body temperature?

A
  • at normal temperature the thyroid hormone receptor (transcription factor) binds to a section of DNA at the start of a gene
  • this means the gene cannot be expresses and is ‘switched off’
  • in colder temperatures the body will releases the hormone thyroxine which binds the thyroid hormone receptor allowing RNA polymerase to bind to the start of the gene making it ‘switched on’
  • this protein increases the metabolic rate
109
Q

What is a transcription factor?

A

A protein that controls the rate of transcription of a protein, by binding to a specific DNA sequence.

110
Q

How does hormones affect physical cell mechanisms from outside of the cell?

A
  • hormones that cannot cross the cell membrane bind to receptors on cell surface membrane
  • this initiates a process that activates the secondary messengers
  • the activated secondary messenger molecule activates enzymes called protein kinases
  • this triggers a chain of reactions (cascade) inside the cell resulting in the change of transcription factors which then may affect gene expression inside the cell
110
Q

How does hormones affect physical cell mechanisms from outside of the cell?

A
  • hormones that cannot cross the cell membrane bind to receptors on cell surface membrane
  • this initiates a process that activates the secondary messengers
  • the activated secondary messenger molecule activates enzymes called protein kinases
  • this triggers a chain of reactions (cascade) inside the cell resulting in the change of transcription factors which then may affect gene expression inside the cell
111
Q

How does to little exercise affect bodily health?

A
  • increased risk of obesity
  • increased risk of CVD
  • increased risk of diabetes
112
Q

How do you analyse data of the effects of exercise on the body?

A
  1. Describe the main trend in the data using the data numbers (e.g highest %)
  2. Draw a conclusion (correlation does not mean causation)
113
Q

How does do much exercise affect bodily health?

A
  • wear and tear on joints
  • suppressed immune system (makes the individual more susceptible to disease.
114
Q

What are the techniques used by modern medicine to enable people with disabilities and injury to participate in sports?

A
  • key hole surgery
  • prostheses
115
Q

What is key hole surgery?

A

This is when a small camera and medical instruments is inserted into a small incision in the skin to perform surgery.

116
Q

What are the advantages of keyholes surgery?

A

-less blood loss and scarring
- quicker recovery and lower pain after surgery
- less chance of infection

117
Q

What’s an example of keyhole surgery?

A

Fixing a damaged cruciate ligament (middle of the knee, connects thigh bind to lower leg bone), if damaged it can be removed and replaced by a graft.

118
Q

What are prostheses?

A

This is when a damaged of missing body part is replaced with an artificial version. They can be connect to electronic devices that can ‘read’ information from the nervous systems to operate the body part.

119
Q

What an example of prostheses?

A

Replacing damaged knee joint, the damaged cartilage is replaced by a metal device to create a smooth surface.

120
Q

What are performing enhancing drugs?

A

This are drugs that improve a person’s performance in sport activities. This gives them an unfair advantage over their opponents.

121
Q

What are the different types of performance enhancing drugs?

A
  • anabolic steroids (increase muscle size)
  • stimulants (more alert and react faster)
  • narcotic analgesics (strong painkillers)
122
Q

What are the arguments for the use of performance enhancing drugs?

A
  • athletes should have the freedom to choose if they want to deal with the risk
  • may help over come inequalities in competitive sport
  • competing at a higher level may only be possible fore some athletes if they are using them
123
Q

What are the arguments for the use of performance enhancing drugs?

A
  • many of them are illegal
  • gives athletes an unfair advantage
  • high amount of health risk associated with them
124
Q

Core practical 16: Investigate the rate of respiration. Variables

A

Control > number of organism, temperature and time taken place
dependent variable > the distance the fluid/ink has moved along the pipettes

125
Q

Core practical 16: Investigate the rate of respiration. Method

A
  1. Place an organism into the tube and replace the bung
  2. Place a drop of dye unit the glass tube
  3. Open the three way tap, this increases the pressure moving the dye furthest away from the test tube
  4. Mark the start of the fluid with a marker
  5. Close the connection and immediately start the stopwatch
    6.make the positions on the palette tube every minute for 5 minutes (as the organism respire the decrease in pressure causes the dye to be moved towards the test tube)
  6. Measures the complete distance travelled and record in a suitable tables and repeat
126
Q

How can the volume of oxygen consumed be calculated?

A

Pir^2h

R > diameter of capillary tube (cm)
H > distance moved (cm)

127
Q

Core practical 17: investigate the effect of exercise on tidal volume, breathing rate, respiratory minute ventilation and oxygen consumption using data from spirometer. Variables

A

Control > the person, time, temperature
Dependent > rate of respiration
Independent > level of exercise

128
Q

Core practical 17: investigate the effect of exercise on tidal volume, breathing rate, respiratory minute ventilation and oxygen consumption using data from spirometer. Method

A
  1. Place a canister of soda lime between mouthpiece and floating chamber (absorbs CO2)
  2. Calibrate the spirometer (filled with oxygen)
  3. Subject outs nose piece in and place mouthpiece in mouth and twitch in recording apparatus
  4. Subject breath into the tube breathing normally then more deeply
    5.record the results and compare
129
Q

How does calculate tidal volume and oxygen consumption from a spirometer?

A

Breathing rate > count number of peaks in a minutes
Tidal volume > calculating average differcnd in the volume of gas between peaks
Oxygen consumption > change of volume

A Level Biology (Salters-Nuttfield SNAB) (8 decks)

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