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Biology > Topic 7 > Flashcards

Topic 7 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

What attaches skeletal muscle to bone?

A

Tendons

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2
Q

What attaches bone to bone?

A

Ligaments

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3
Q

What is skeletal muscle made up of?

A

Muscle fibres

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4
Q

What is the cell membrane of muscle fibre cells called?

A

Sarcolemma

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5
Q

What is sarcolemma?

A

The cell membrane of muscle fibre cells

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6
Q

What is sarcoplasm?

A

A muscle cell’s cytoplasm

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7
Q

What are transverse (T) tubules?

A

Infolds of sarcolemma which distribute electrical impulses throughout the sarcoplasm so they reach all parts of the muscle fibre

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8
Q

What is the sarcoplasmic reticulum?

A

Internal membranes running through the sarcoplasm. Stores and releases calcium ions

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9
Q

What is special about the contents of muscle fibre cells?

A

Contain main ATP, are multinucleate (contain many nuclei), contain myofibrils

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10
Q

What are myofibrils?

A

Long, cylindrical organelles made up of proteins specialised for contraction

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11
Q

What is the structure of a myofibril?

A

Contains thick and thin myofilaments that move past each other in contraction. Made of many repeating units called sarcomeres. Also contains tropomyosin and troponin

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12
Q

What are thick myofilaments made of?

A

Myosin

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13
Q

What are thin myofilaments made of?

A

Actin

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14
Q

What is the structure if myosin filaments?

A

Thicker myofilaments. Hinged globular heads that can move back and forth. Myosin heads have a binding site for actin and a binding site for ATP

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15
Q

What is the structure of actin filaments?

A

Thinner myofilaments. Have binding sites for myosin heads

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16
Q

What is the function of tropomyosin and troponin?

A

Tropomyosin blocks actin-myosin binding site in a resting muscle and is held in place by troponin. Troponin changes shape when Ca2+ binds, which moves tropomyosin out of the way

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17
Q

How does muscle contraction take place?

A

1) Action potential from motor neurone depolarises the sarcolemma.
2) Depolarisation spreads down T-tubules to the sarcoplasmic reticulum
3) Ca2+ released into sarcoplasm
4) Ca2+ binds to troponin, changing its shape, moving tropomyosin and exposing binding sites
5) Myosin head can bind to actin filament
6) Ca2+ ions also activate ATPase which breaks ATP down and provides energy
7) This energy moves the myosin head, pulling actin filament along
8) ATP also provides energy to break actin-myosin cross bridge so the head detaches
9) Head attaches to a different binding site, repeats cycle
10) Cycle continues as long as Ca2+ is present and bound to troponin

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18
Q

What happens when muscle excitation stops?

A

Ca2+ leaves troponin binding sites. Moved by active transport back into sarcoplasmic reticulum. Troponin returns to original shape. Tropomyosin again blocks binding sites. Actin filaments slide back to relaxed position.

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19
Q

Properties of slow twitch muscle fibres?

A 
Contract slowly
Used for posture
Good for endurance
Work a long time without tiring
Energy released aerobically
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20
Q

Properties of fast twitch muscle fibres?

A 
Contract quickly
Used for fast movement
Good for short burst of power
Tire quickly
Energy released anaerobically
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21
Q

What are the four stages of aerobic respiration?

A

Glycolysis, the link reaction, the Krebs cycle and oxidative phosphorylation

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22
Q

Where does Glycolysis occur?

A

Cytoplasm of cells

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23
Q

Where does the link reaction occur?

A

Matrix of Mitochondria

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24
Q

Where does the Krebs cycle occur?

A

Matrix of Mitochondria

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25
Q

Where does oxidative phosphorylation occur?

A

Inner Mitochondrial Membrane

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26
Q

What happens in the first stage of aerobic respiration?

A

Glycolysis: One molecule of glucose is split into two molecules of pyruvate

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27
Q

What are the two stages of glycolysis?

A

Phosphorylation and oxidation.
1) Glucose phosphorylated by 2 molecules of ATP - creates 2 molecules of triose phosphate and 2 ADP

2) Triose phosphate loses hydrogen to form 2 pyruvate. NAD collects hydrogen ions, forming 2 reduced NAD. Process produces 4 ATP but net gain is 2 ATP for glycolysis

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28
Q

What happens in the second stage of aerobic respiration?

A

The link reaction:

1) Pyruvate decarboxylated (carbon removed) - one C removed in form of CO2
2) NAD is reduced by collecting hydrogen from pyruvate. Pyruvate becomes acetate
3) Acetate combined with coenzyme A to form acetyl coenzyme A
4) No ATP produced here

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29
Q

How often do the link reaction and Krebs cycle occur per glucose molecule?

A

Twice

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30
Q

What happens in the third stage of aerobic respiration?

A

The Krebs Cycle:

1) Acetyl CoA combines with oxaloacetate to form citrate. CoA reused in link reaction.
2) 6C citrate converted to 5C molecule be decarboxylation. Also dehydrogenated and reduced NAD produced
3) 5C molecule converted to 4C molecule - decarboxylation and dehydrogenation which produces 1 reduced FAD and 2 reduced NAD
4) ATP produced by direct transfer of phosphate ground from an intermediate compound to ADP. This is called substrate level phosphorylation. Oxaloacetate has been reformed from citrate.

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31
Q

Fate of 1 coenzyme A from Krebs?

A

Reused in link reaction

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32
Q

Fate of Oxaloacetate from Krebs?

A

Regenerated and used in next Krebs cycle

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33
Q

Fate of 2 CO2 from Krebs?

A

Released as waste

34
Q

Fate of 1 ATP from Krebs?

A

Used for energy

35
Q

Fate of 3 reduced NAD from Krebs?

A

Goes to oxidative phosphorylation

36
Q

Fate of 1 reduced FAD from Krebs?

A

Goes to oxidative phosphorylation

37
Q

What happens in the fourth stage of aerobic respiration?

A

Energy carried by electrons from reduced coenzymes (NAD and FAD) is used to make ATP

38
Q

What are the two processes of oxidative phosphorylation?

A

1) Hydrogen atoms released by reduced coenzymes as they are oxidised.
2) H atoms split to H+ and e-
3) Electrons move along electron transport chain, losing energy which is used to pump protons from the mitochondrial matrix into the intermembrane space
4) This forms electrochemical gradient of protons, higher in the intermembrane space than matrix
5) Protons move back down gradient into mitochondrial matrix via ATP synthase
6) At the end of the transport chain, protons, electrons and O2 from blood combine to form water. Oxygen is the final electron acceptor.

39
Q

What is the name of the movement of H+ ions across a membrane to produce ATP called?

A

Chemiosmosis

40
Q

How many ATP can be made from one glucose in aerobic respiration?

A

32

41
Q

How can you measure rate of respiration?

A
  • Using a respirometer. Measures rate of oxygen uptake.
  • 2 tubes, syringe, manometer, closed tap, woodlice, beads of same mass as woodlice
  • Potassium hyrdoxide solution in each tube to absorb CO2
  • Syringe use to set manometer fluid to known level
  • Pressure change moves liquid toward test tube
  • Distance moved measured and used to calculate O2 vol per minute
42
Q

How does anaerobic respiration work?

A

Lactate fermentation:

  • Glucose converted to pyruvate via glycolysis
  • Reduced NAD from glycolysis transfers hydrogen to pyruvate to form lactate and NAD
  • NAD reused
43
Q

What is the fate of lactate?

A

Converted back to pyruvate by cells or glucose by the liver

44
Q

What does myogenic mean?

A

A muscle that can contract and relax without receiving signals from neurones

45
Q

How is heartbeat regulated?

A
  • SAN sends out regular waves of electrical activity through the atrial walls causing atria to contract simultaneously
  • Band of collagen is non conducting and prevents electrical signal reaching ventricles directly
  • Waves reach AVN - there is a slight delay and then the waves are passed on to the bundle of His
  • Passed down bundle of His
  • Carried by Purkyne fibres into the muscular walls of the left and right ventricles causing bottom up simultaneous contraction
46
Q

What and where is the SAN?

A

Sinoatrial node - wall of the right atrium

47
Q

What and where is the AVN?

A

Atrioventricular node - wall of right atrium

48
Q

What is the bundle of His?

A

Group of muscle fibres responsible for conducting waves of electrical activity to the Purkyne fibres

49
Q

What are the Purkyne fibres?

A

The finer muscle fibres in the right and left ventricle walls

50
Q

What is an ECG?

A

Electrocardiograph

51
Q

What does an ECG do?

A

Records the electrical activity of the heart

52
Q

What are the components of an ECG trace?

A

P, Q, R, S and T

53
Q

What causes P wave?

A

Contraction of atria

54
Q

What is the QRS complex?

A

Main peak, caused by contraction of ventricles

55
Q

What causes the T wave?

A

Relaxation of ventricles

56
Q

What is a normal heart rate?

A

60-100 bpm

57
Q

What is increased heart rate called?

A

Tachycardia

58
Q

What is tachycardia?

A

Increased heart rate, sign of heart failure

59
Q

What is fibrillation?

A

Irregular heart beat

60
Q

What is an irregular heat beat called?

A

Fibrillation

61
Q

What is the medulla?

A

Part of the brain controlling breathing rate and heat rate

62
Q

What controls breathing rate?

A

Part of the brain called the medulla

63
Q

What is the the structure of the medulla?

A

Has areas called ventilation centres - the inspiratory centre and expiratory centre
Also has cardiovascular control centre

64
Q

How does the medulla control breathing rate?

A
  • Inspiratory centre in medulla sends nerve impulses to intercostal and diaphragm muscles making them contract. Increases volume and decreases pressure of lungs, drawing in air
  • Stretch receptors stimulated which send impulses to medulla, inhibiting the action of the inspiratory centre
  • Expiratory centre sends nerve impulses causing the diaphragm and intercostal muscles to relax, causing deflation of lungs
65
Q

How is increased breathing rate triggered by exercise?

A
  • Level of CO2 in blood increases, reducing pH
  • Changes in blood pH detected
  • Nerve impulses sent to medulla which sends more frequent impulses to diaphragm and intercostal muscles
66
Q

How is blood pH detected?

A

Chemoreceptors in the medulla, aortic bodies and cartoid bodies

67
Q

What is ventilation rate?

A

Volume of air breathed in or out in a period of time

68
Q

What does heart rate change in response to?

A
  • Blood pH increases, detected by chemoreceptors

* Pressure changes it accordingly, detected by pressure receptors in aorta wall and carotid sinuses

69
Q

What is cardiac output?

A

Total volume of blood pumped by a ventricle every minute

70
Q

What is stroke volume?

A

Volume of blood pumped by one ventricle per contraction

71
Q

What is tidal volume?

A

The volume of air in each breath

72
Q

What is breathing rate?

A

Breaths per minute

73
Q

How can tidal volume and breathing rate be measured?

A

With a spirometer. Person breathes in oxygen from oxygen chamber and breathes back into it. Soda lime in the tube absorbs CO2. Movement of lid of chamber recorded

74
Q

What part of the brain regulates body temperature?

A

The hypothalamus

75
Q

How do transcription factors help regulate temperature?

A

Bind to DNA sites near the start of genes and alter rate of transcription. At low temperature a hormone binds to a transcription factor for a protein affecting metabolic rate, increasing rate of transcription for it.

76
Q

Advantages of keyhole surgery?

A
  • Less blood loss
  • Less scarring
  • Less pain
  • Quicker recovery
  • Easier to return to normal activities
  • Shorter hospital stays
77
Q

What are examples of performance enhancing drugs?

A

Anabolic steroids
Stimulants
Narcotic analgesics

78
Q

What do anabolic steroids do?

A

Increase strength, speed and stamina by increasing muscle size and allowing athletes to train harder. Also increase aggresion

79
Q

What do stimulants do?

A

Speed up reactions, reduce fatigue, increase aggression

80
Q

What do narcotic analgesics do?

A

Reduce pain, so injuries don’t affect performance

Biology (7 decks)

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