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A Level Biology > Topic 7 > Flashcards

Topic 7 Flashcards

1
Q

Where do muscles bring about movement

A

At joints

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2
Q

What is antagonistic muscles pairs

A

Muscle pairs that work together to create movement

Ie one flex one extends
One contract one relax ie bicep and triceps

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3
Q

What is an extensor

A

Is a muscle that contracts which brings about extension

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4
Q

What is a flexor

A

A muscle that contracts and brings about movement with the muscle bending

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5
Q

Name all the parts of joint and there function

A

Synovial fluid-acts as a lubricant allows the joint to move freely
Ligaments- attach bone to bone
Cartilage-it’s absorbs synovial and acts as a shock absorber
Tendon -attach bone to muscle
Fibrous capsule -they aid in enclosing joints

Synovial membrane-they secret synovial fluid that acts as a fluid

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6
Q

What are muscle made up of

A

Muscle fibres

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7
Q

State the content of a muscle fibres

A 
Mitochondria 
Cytoplasm 
Myofibrilis 
Several nucleus 
They are stripped
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8
Q

What is the sacromere

A

A series of contractile units that make up myofobrils

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9
Q

What the two proteins found in sacromere

A

Actin

Myosin

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10
Q

What two protein molecules are associated with actin molecules

A

Troponin and troppmyosin

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11
Q

What causes ca ions to be released from the sarcoplasmic reticulum

A

By nerve impulses arriving at the neuromuscular junction

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12
Q

Describe every stage of the sliding filament theory

A

Ca ions bind onto the troponin molecule causing it to move this in turn causes tropomyosin to move this action exposes the myosin binding site

The myosin head can now attach onto the binding site on the actin causing a cross bridge to form

The binding of the myosin to actin causes ADP and p1 to be released which means the myosin head no foward as it changes shape meaning actin can move over the myosin toward the sacromere

ATP binds onto the myosin head causing it to detach from the actin then atpase on the myosin head hydrolysis the ATP into ADP and p1

This hydrolysis causes the myosin head to change shape and stand up right so the cycle starts again

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13
Q

What do the troponin and tropmyosin prevent

A

They prevent the binding of the actin head with the binding site as they block it

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14
Q

What is basal metabolic rate

A

It’s the minimum amount of energy required to keep us alive(at rest)

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15
Q

What factors are basal metabolic rate dependant on

A

Age
Gender
Surface area
Body fat

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16
Q

How is ATP made and what is the reaction called

A

It’s made when an inorganic phosphate combines together wit ADP and the reaction is called phosphorylation

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17
Q

Describe how ATP works to produce energy

A

A phosphate is removed from the ATP forming ADP and the phosphate is hydrated in water it forms bond and this releases a lot of energy to drive reactions in cells

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18
Q

What is glycolysis and where does it occur

A

It occurs in the cytoplasm of cells and it’s the intial stages of carbohydrate breakdown

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19
Q

In glycolysis what is glycogen converted into and what’s an issue with its

A

Glucose but it’s unreactive and stable

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20
Q

Describe the stages in glycolysis

A

Two phosphate groups are added from ATP molecules to glucose which increases its reactivity

Which is split into two molecules of phosphorylated 3 carbon compounds

Which are then oxidised to produce 2 3 -carbon compounds called pyruvate

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21
Q

The two hydrogen atoms removed during glycolysis what happens to them

A

They are taken up by coenzyme NAD

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22
Q

What is substrate-level phosphorylation

A

When a phosphate from immeadiate compound 3Cis transferred to ADP to make ATP

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23
Q

What does the 3c pyruvate do if oxygen is available

A

It’s passes into the mitochondria (completely oxidised to Co2 and H2o

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24
Q

What are the 2 pathways called

A

Link reaction

Krebs cycle

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25
Q

Describe what happens in link reaction

A

Pyruvate is decarbocylated in which co2 is released,dehydrogenated in which 2Hs are removed

The 2 carbon compound that forms combined with Co enzyme A to Acetyl CoA

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26
Q

What happens to the acetyl groups that are produced

A

They are carried by co enzyme a to the Krebs cycle

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27
Q

What happens in Krebs cycle where does it occur and state what things are produced

A

It takes place in mitochondria the acetyl compound reacts with a 4C compound to make a 6 C compound and the cycle continues in which the 4C is recreated

4 pairs of hydrogen molecules are made by dehydrogenation

2Co2 molecules are produced by decarboxylation

An ATP is made by substrate level phosphaylation

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28
Q

What happens to the 4 pairs of hydrogen molecules produced in the Krebs cycle

A

They are taken by hydrogen acceptors co enzyme NAD and FAD to be used in ATP production

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29
Q

Describe each step in ATP synthesis,chemiosis

A

Step 1-2H+ and electrons are carried by reduced co enzyme to the electron transport chain in the inner mitochondrial memebrane

Electrons pass from one electron carrier to the next in a series of redox reactions,when it recovers the electron its reduced and when it’s passed on its oxidised

As electrons pass along the chain energy is released which is used in moving hydrogen ions into the inter membrane space after moving across the inner mitochondrial membrane (high h+ created)

This creates an electrical gradient as a result a result across the inner memebrane as there’s a large difference of h+ ions across the memebrane,with the intermembrane space being more positive than the matrix

The hydrogen ions will diffuse down this electrical gradient through protein channels in ATP synthase as they pass through channels,ATP synthesis is catalysed by ATP synthase,hydrogen ions cause the active site of the enzyme to change which enables ATP and phosphate ions to bind to the site allowing synthesis of ATP

In the matrix hydrogen atoms are from when h+ electrons combine with each other they also combine with oxygen to form water

Ions

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30
Q

What is the synthesis of ATP called and why

A

Oxidative phosphorylation

Because oxidation and reduction reaction occur in the electron transport chain

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31
Q

In ATP synthesis how is the electrical gradient created

A

By hydrogen ions moving across the inner mitochondria membrane and into the intermembrane space

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32
Q

How are the hydrogen ions in ATP synthesis moved

A

Energy from the electrons passing along the electron transport chain is used in moving hydrogen ions

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33
Q

How does anaerobic respiration differ from aerobic respiration

A

It doesn’t invovle link reaction,Krebs cycle or oxidative phosphorylation

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34
Q

What happens in anaerobic respiration

A

Glucose is converted by glycolysis into pyruvate

Reduced nad from glycolysis transfer hydrogen to pyruvate which forms lactate and NAD

The lactate regenerates NAD this enables glycolysis to continue and a small amount of ATP can be produce d

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35
Q

State why oxygen is important in the electron transport chain and what will happen if it’s not present

A

It act as the final electron carrier of it’s not present the chain will stop working,no reduced NADp will be produced either

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36
Q

What impact does lactate have on muscles and why does it mean anaerobic respiration doesn’t last long

A

It builds up and in solution forms lactic acid meaning ph falls which inhibits enzymes that catalyse glycolysis reactions

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37
Q

Explain how lactate inhibits enzymes in glycolysis

A

Lactic acid has hydrogen ions and they neutralise negatively charged groups in the active site of an enzyme

This means it affects the attraction between the charged groups on substrate and on the active site meaning they can no longer bind to each other

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38
Q

What is creatine phosphate used for

A

It’s used in the immeadiate regeneration of ATP and it’s used when supplying instant energy

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39
Q

What is aerobic capacity

A

The ability for the body to take in transport and use oxygen

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40
Q

What is meant by VO2

A

It’s s the amount by of oxygen we consume per minute

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41
Q

What is meant by VO2 max and give the units

A

It’s the amount of oxygen we consume per minute during maximum aerobic excerise

Min-1 kg-1

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42
Q

What is cardia output and how is it calculated

A

The volume of blood ejected from the heart in a minute

Stroke volume * heart rate

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43
Q

What is stroke volume

A

This is each time the ventricle contracts the volume of blood that’s ejected by the left ventricle cm3

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44
Q

What is stroke volume determined by

A

Venous return which is the amount of blood returning to the heart

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45
Q

When measuring heart rate where do we take a pulse from

A

Radial wrist and carotid artery

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46
Q

What is meant by the heart by myogenic

A

It means it can contract without external nervous stimulation

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47
Q

How does the heart contract

A

The heart muscle cells become depolarised in which the charges are reversed

The change in polarity spreads from cell to cell causing contraction of. The heart

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48
Q

Describe the steps in the contraction of a single heart beat

A

Depolarisation occurs at the Sinoatrial node which generates an electrical impulse

This impulse spreads across the left and right atria which causes them to contract

It travels to the atrioventricular node and conducts an impulse to the ventricles after a delay of 0.13

The signal then reaches the purkyne fibres after a delay and they conduct the impulses quickly to the apex of the ventricles

The fibres divide into branches that penetrate into the ventricle muscles and these brackets carry impulses to the inner dells within the ventricles and it spreads through the walls of the ventricle

The first ventricular cells are depolarised at the apex of the heart,contractions begin there and travel upwards towards the atria and a wave of contraction is produced that moves up the ventricles pushing blood into the aorta and pulmonary artery

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49
Q

In the contraction of the heart why is the delay important

A

It ensures the atria have finished contracting and the ventricles have filled with blood before they contract

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50
Q

What is an ECG used for

A

To measure the electrical activity of the heart

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51
Q

State the four waves in an ECG and what they mean

A

P-wave- this is when depolarisation of the atria occurs and it leads to atrial contraction(atrial systole)

PR internal-this is the time it takes impulses to be conducted from the SAN across the atria to the ventricles w through the avn

QRS complex- It’s the wave of depolarisation that results in the contraction of ventricles (ventricular systole)

T-Wave- this is during the hearts relaxation phase and repolarisation of the ventricles

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52
Q

What is braclycardia

A

When heart rate is less than 60 bpm

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53
Q

What is tachycardia

A

When heart rate is greater than 100 bpm

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54
Q

What is asystole

A

When there no heartbeat

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55
Q

What is meant by arrhythmia

A

Arrhythmia-is when electrical disturbances are caused by irregular heart beats

Is

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56
Q

What is the role of the cardiovascular control centre and where is it located

A

It’s controls heart rate and it’s located in the medulla oblongata

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57
Q

What is the function of the sympathetic and vagus nerve

A

Sympathetic nerve increases our heart rate by sending impulses to the sinoatrial node

Vagus nerve causes heart rate to slow down

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58
Q

What things does the cardiovascular control detect

A

Co2 accumulation
Lactate in blood
Reduction in oxygen

Rise in temperature

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59
Q

What impacts does adrenaline have on our heart rate

A

It has an impact on the sinoatrial node in which it causes heart rate to increase

It causes vasodilation of arterioles that supply muscles and constriction of arterioles that go to the digestive system which maximises blood flow to the active muscles

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60
Q

What is tidal volume

A

The volume of air we breathe in and out at each breath at rest

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61
Q

What is vital capacity

A

The max volume we can inhale and exhale on average

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62
Q

What is minute ventilation

A

The volume of air taken into the lungs in a minute

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63
Q

How is our breathing controlled

A

By the ventilation centre in the medulla oblongta

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64
Q

What happens in inhalation

A

The ventilation centre sends nerve impulses to the diaphragm muscles and external intercostal muscles and they contract which brings about inhalation

65
Q

Describe what happens in exhalation

A

In the bronchioles stretch receptor are stimulated by the inhalation of the lungs and they send inhibitory impulses back to the ventilation centre

This causes impulses to muscles to stop and they reflex enabling exhalation.

66
Q

What is residual air

A

Air that hasn’t been expelled which mixes with inhaled air

67
Q

How do you work out minute ventilation

A

Tidal volume *number of breathes

68
Q

In fight or flight what happens when are stretch receptors are stimulated

A

Impulses are sent to the our cardio vascular centre

69
Q

In fight or flight describe what happens when impulses are sent to the CV centre (stroke volume and venous return

A

It causes our heart rate to raise via the sympathetic nerve which leads to increased venous return and stroke volume

Cardiac output increases as a result of the raised heart rate and stroke volume which means oxygen is transported faster around the body

70
Q

In fight or flight how is blood pressure prevented from exceeding a limit and explain what happens

A

By negative feedback,in this process nerve impulses are sent by pressure receptors in the aorta and carotid artery to the cv centre

It results in inhibitory nerve impuls s being sent from the Cv centre to the sinoatrial node

71
Q

State the key component in the controlling of breathing rate and depth

A

The concentration of dissolved co2 in the blood

72
Q

What happens when co2 dissolves in blood

A

The Carbonic acid dissociates into hydrogen and hydroencarbonate ions ph lowers

73
Q

Describe how breathing rate and depth is controlled during exercise

A

Chemoreceptors are sensitive to hydrogen ions and they detect the rise in their concentration (they are located in the ventilation centre of the medulla oblongata)

Impulses are sent to other parts of the ventilation centre and then are sent from on the ventilation centre of which help in stimulating muscles that are involved in breathing

74
Q

Explain how the carotid artery and Aorta are involved in controlling breathing rate and depth

A

In their walls they contain chemoreceptors and they are to stimulated by changes in ph

Impulses at sent to the ventilation centre

They have receptors that monitor blood

75
Q

Describe how breathing is controlled in exercise

A

Impulses are sent from the motor cortex to the ventilation centre in the medulla oblongata which causes ventilation to increase

Stretch receptors in muscles and tendons also send impulses to the ventilation centre which also allows ventilation to increase (that are involved in movement

Chemoreceptors that are sensitive to co2 levels and to Change s in blood temperature increase the depth and rate of breathing via the ventilation centre

76
Q

What are slow twitch fibres

A

These fibres are specialised for slowed,sustained contraction are to cope with long amounts of exercise

77
Q

What are fast twitch fibres and where does the ATP used for them come from

A

These fibres are specialised to produce rapid intense contraction ATP is done made for anaerobic gylycoylsis

78
Q

State the role of actin in the sliding filament theory

A

Contains myosin bond sites

79
Q

State the role of myosin

A

Contains ADP and pi and attached to myosin sites on actin this releases ADP and Pi causing head to nod foward

80
Q

State the role of troponin and tropmyosin

A

Both cover myosin bindings sites with troponin causing tropomyosin to move

81
Q

State the role of calcium 2+ ions

A

They cause the movement of troponin and tropomyosin by binging to the troponin

82
Q

State the role of ATP

A

Cause the separation of actin and myosin by binding to myosin

83
Q

State the role of atpase

A

Hydrolysis ATP on the myosin to ADP and pi causing myosin head to change back to normal

84
Q

When the muscle relaxs what happens in the sliding filament theory

A

It’s not stimulated by nerve impulses, ATP is used to actively pump out ca ions out of the muscle sacroplasm and troponin and trypomyosin move over blocking the myosin bindings sites

85
Q

In aerobic respiration why aren’t glucose and oxygen brought together directly

A

It would result in a large release of energy that happens to quickly which could damage the cell

86
Q

State where the electron transport chain is located in

A

Inner mitochondrial membrane

87
Q

State where the H+ ions that are moved by the energy of the etc come from

A

The hydrogen ions came from the one released via glycolysis,Krebs cycle link reaction

88
Q

Where is ATP synthase located

A

In the inner mitochondrial membrane

89
Q

In The etc what is the very last step

A

H ions and electrons recombine to form hydrogen atoms and combine with oxygen to form water

90
Q

What is the role of ATP synthase in oxidative phosphorylation

A

It’s the enzyme that catalyses the reaction between ADP and pi to produce ATP

91
Q

What is end point inhibition

A

It’s how the rate of respiration is controlled

As ATP Inhibts an enzyme that’s responsible for the phosphorylation of glucose by doing so it means glycolysis can’t occur

92
Q

State how lactate is formed in anaerobic respiration and why it’s formation enables a small amount of ATP to be produced

A

Pyruvate at the end of glycolysis is reduced by adding two hydrogens forming lactate

This oxidises the reduced Nad meaning it can carry more hydrogen ions so anaerobic respiration can continue

93
Q

Why is oxygen uptake greater than normal in the recovery period

A

As more oxygen is needed to fuel the oxidation of lactate into pyruvate

94
Q

Explain how creatine phosphate regenerates ATP

A

It’s hydrolysed and it provides energy along with a phosphate which combines with ADP forming ATP

95
Q

What is the use of creatine phosphate to regenerate ATP known as

A

The ATP/PC system

96
Q

State the 3 energy syttens in the body

A

ATP/PC system
Anaerobic respiration
Aerobic respiration

97
Q

What happens in anaerobic respiration.

A

Pyruvate is reduced forming lacatate and glycolysis still occurs

98
Q

When is the ATP/PC system used

A

During intense exercise and provide energy for 6-10 seconds ie sprinting/throwing

99
Q

How is creatine phosphate regenerated

A

From ATP when the body is at rest

100
Q

In anaerobic respiration how are the co enzymes nad reduced

A

They are used to reduce pyruvate into lactate

101
Q

During intense exercise what would you expect to happen to cardiac output

A

It would increase because strike volume and heart rate would also as venous return to the heart is faster in which more blood can be expelled faster

102
Q

State the role of the sinoatrial node and its location

A

It’s located in the wall of the right atrium beneath the superior vena cava

It’s where depolarisation first starts and it’s non as the pacemaker it sends electrical impulses to the AVN

103
Q

What is the role of the AVN

A

It sends electrical impulses after a delay to the purknye fibres

104
Q

State the role of the bundle of His

A

They are a collection of purkyne fibres together

105
Q

State the role of the bundle of his and purkyne fibres

A

They carry electrical impulses into the ventricles as they have smaller branches that spread into each ventricle this causes the cells in the ventricles to contract as they are depolarised and this continues upwards towards the atria

106
Q

During excerise how is blood pressure prevented from rising too far

A

Pressure receptors in the aorta and in the carotid artery send nerve impulses back to the cardiovascular control centre

The CCC sends inhibitory nerve impulses from here to the sinoatrial node

107
Q

What is this process known in the lowering of blood pressure

A

It’s called negative feedback

108
Q

State how the cardiovascular centre increases heart rate in fight or flight and state what impact it has blood distribution

A

It’s sent impulses by stretch receptors in the muscles and tendons this causes heart rate to raise via the sympathetic nerve which increases venous return which leads to rise in stroke volume this in turn increases cardiac output meaning oxygen and fuel is transported around the body faster

109
Q

What is homeostasis

A

It’s the maintaince of a stable internal environment

110
Q

What is meant by negative feedback

A

A mechanism that restores the levels of substances in the body back to normal

Ie blood pressure

111
Q

What is meant by positive feedback

A

This system results in the amplification of the change so it exceeds normal levels

112
Q

Describe how negative feedback works

A

Receptors in the body detect a deviation from the norm

They are connected to the control centre which communicates to effectors

Which counteract and bring levels back to normal

113
Q

In negative feed back give examples of effects

A

Muscles

Glands

114
Q

How does negative feedback work in terms of ranges

A

It works within very narrow limits

115
Q

Give examples of negative feedback in the body

A

Glycolysis

Controlling blood pressure

Core body temperature

116
Q

Give examples of positive feedback in the body

A

Blood clotting

Atherosclerosis

117
Q

What is thermoregulation and state what normal core body temperature is

A

Its the control of the body temperature

37.5wwe

118
Q

What detects changes in blood temperature and where are they located

A

Receptors and they are found in the hypothalamus

119
Q

What is the role of theromreceptors

A

They are on the skin and they detect temperature changes and they send impulses to the hypothalamus

120
Q

When our core body temperature is too high state changes in our body that occur and state what causes these changes to happen

A

The high temperature is detected by thermoreceptors and they send impulses to the hypothalamus

They cause the sweat glands to secrete sweat which evaporates which take heat energy from the skin

Vasodilation of the arterioles which means they become wider and relax and more blood flows closer to the skin and energy is lost by this (shunt vessel contricts)

121
Q

In colder climates state the way the body keeps core body temperature constant

A

Skeletal muscles shiver which helps to increase body temperature

Vasoconstriction- the arterioles constrict which reduces blood supply to the surface capillaries meaning we lose less energy

Hair contract- this traps layers of air which insulated the body

122
Q

What are the 4 ways of energy

A

Conduction-this involved direct contact with an object resulting in enegry transfer ie pouring water

Convection-the bulk movement of air as it heats and explants

Radiation -when we warm the environments
Evaporation

123
Q

During exercise our core body temperature increases state the processes that go in our body that lower body temperature

A

Evaporation of sweat from surfaces of lungs and of skin help in increasing enegry loss

Arteriole vasodilation which increases enegry loss by conduction,convection,radiation

124
Q

What is chemiosmosis

A

The movement of H+ ions across a memebrane generating ATP

125
Q

What type of lymphocyte is moderate exercise believed to enhance

A

Natural t killer cells

126
Q

How do natural killer cells work

A

They provide non specific immunity

They release a protein called perforin which makes pores in the targeted cell membrane which later leads to cell apoptosis

127
Q

Why is doing vigorous exercise an issue at times

A

It’s beloved to suppress the immune system with

Natural killer cells,phagocytes,B cells and t helper cells being suppressed in

128
Q

How does the antibody production fall with very vigorous exercise

A

The decrease in T helper cells reduces the amount of cytokines that’s available to activate lymphocytes

129
Q

What was the issue with using previous technology for treating damaged joints

A

Lots of pain

Prolonged recovery

Increased chance of infection

Large incision

130
Q

Describe ways that damage can occur on joints

A

Ligaments can be damaged by sudden twisting/abrupt movements

Cartilage that covers surfaces of bones may wear away causing bones to grind onto each other

131
Q

What is keyhole surgery

A

When small incision are made in the joint and optical fibres are used to repair the joint

132
Q

Give reasons as to why keyhole surgery is more effective

A

Recovery after keyhole surgery is faster

Less bleeding

Less recovery time

Shorter hospital stay

133
Q

What are prosthesis

A

It’s when an artificial body part is used by someone with a disability enabling them to regain a degree of normal function

134
Q

What problems can occur with doing to little excerise

A

Higher blood pressure leads to CDHD

Gain weight

Increased ldls

Increase cancer risk

Reduced bone density

Lowered natural killer cells

135
Q

State the benefits of prosthesis

A

They allow people to carry on playing sports

They can replace whole limbs

136
Q

State benefits of doing moderate exercise

A

Lower blood pressure

Increased HDl

Maintain weight

Reduced cancer risk

Increased bone density

More increased natural killer cells

137
Q

State disadvantages of doing to much exercise

A

Poor athletic performance

Chronic fatigue

Increased infections

Increased joint damage

138
Q

What are hormones

A

They are chemical messengers that are released directly into the blood from endocrine glands

139
Q

Describe how hormones work

A

They enter target cells or bind to complementary receptor molecules that can be found on the outside of cell membranes

140
Q

Give the two types of hormone

A

Peptide hormone

Steroid hormone

141
Q

State why peptide hormones can’t pass through the cell membranes

A

As they are charged

142
Q

What are peptide hormones and how do they work

A

They are protein chains

They bind to a receptor on the cell membrane which activates a second messenger in the cytoplasm

The second messenger is responsible for bringing about chemical changes within the cell because it affects gene transcription

143
Q

What are steroid hormones and how do they work

A

They are formed from lipids and they bind directly a receptor molecule within the cytoplasm

Once activated the hormone receptor complex functions as a transcription factor as it switches enzymes on or off

144
Q

What is meant by hormone-receptor acting as a transcription factor

A

They switch enzyme synthesis on or off

145
Q

What is transcription imitated by

A

An enzyme called RNA polyermerase and transcription factors along with regulator proteins binding to DNA

146
Q

In transcription what is the name given to the region that transcription factors bind to

A

Promoter region

147
Q

How do inactive transcription factors become active

A

By the action of hormones

Either by activating second messengers

Or by binding with receptors to become transcription factors

148
Q

Give ways in which transcprition can be prevented

A

By protein repressor molecules attaching to DNA on the promoter region

Or by them binding to transcription factors

149
Q

Name 3 hormones that enhance performance

A

EPo
Creatine
Testosterone

150
Q

What are performance enhancing drug

And give some example

A

They are drugs that enhance and better people’s performance

EPo
Creatine
Testosterone

151
Q

What is EPO and state where it’s produced and it’s function

A

A peptide hormone produced in the kidneys

It’s stimulates the formation of new red blood cells in the bone marrow benefitcal for endurance runners

152
Q

Give health risks of EPo

A

Blood clots
Risk of thrombosis
Stroke
Heart attack

153
Q

What is testosterone and state it’s function

A

It’s a steroid hormone

It’s responsible for the development of male characteristics

154
Q

Why have anabolic steroids been developed to be used instead of testosterone

A

As testosterone breaks down to quickly

155
Q

Give the side effects of anabolic steroids

A 
Aggression
Liver damage
Heart disease 
Low sperm count 
High blood pressure
156
Q

What is creatine used for and where can it be found

A

It’s found in fish and meant and it’s benefitcal

,it’s stored in muscles for high intensity sport

157
Q

State side effects with creatine

A 
Vomiting
High blood pressure 
Nausea
Muscle cramps 
Kidney damage
158
Q

What are the axis on a ecg

A

Electrical activity on y

X-time

A Level Biology (9 decks)

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