Question 1

How muscle, tendons, bones, and ligaments interact

Accepted Answer

2 bones joined by ligaments at a joints
Synovial fluid between bones for less friction
Tendons attach muscle to bone, when muscle contact the inelastic tendon pulls on the bone to move it.

Question 2

Muscle structure

Accepted Answer

Muscle made up of muscle fibres joined by connective tissue
Muscle fibres made up of myofibrils
Myofibrils sectioned into sarcomeres 
Sarcomeres made up of actin and myosin

Question 3

Muscle fibre structure

Accepted Answer

Myofibrils surrounded by sarcolemma, transverse tubules, and the sarcoplasmic reticulum
Connected to a motor neuron at the neuromuscular junction

Question 4

Sliding filament theory - receiving the impulse

Accepted Answer

Impulse reaches the neuromuscular junction and spreads through fibre via transverse tubule
Ca2+ released from sarcoplasmic reticulum into sarcoplasm

Question 5

Sliding filament theory - moving the actin

Accepted Answer

Ca2+ binds to troponin on actin causing it to move along with tropomyosin revealing myosin binding sites
Myosin head binds to binding site releasing ADP & Pi forming cross-bridges
Head changes shape, nodding forward and moving the actin over the myosin

Question 6

Sliding filament theory - repeating the movement of actin

Accepted Answer

ATP binds to head causing it to detach
ATPase hydrolyses ATP to ADP and Pi causing head to return to original upright position
Head can now reattach to actin further back to move it more inwards
Overall the sarcomere shortens contracting the muscle

Question 7

Sarcomere, Actin, and Myosin

Accepted Answer

Actin is a beaded molecule containing troponin wrapped by tropomyosin
Myosin is 2 polypeptides wrapped around each other with globular heads
On sarcomere - light band=actin, medium band=myosin, dark band=actin and myosin overlapping

Question 8

Fast and Slow twitch uses

Accepted Answer

Slow twitch = slower sustained contractions for longer periods of work - energy from aerobic respiration, requires more O2
Fast twitch = rapid, intense contractions - energy from anaerobic respiration, requires more glucose

Question 9

Fast and Slow twitch structural and physiological differences

Accepted Answer

Slow twitch have:
more myoglobin (O2 storing) - redder
more mitochondria
less sarcoplasmic reticulum
less glycogen
more capillaries
fatigue slower (less lactate produced)

Differences explained by slow twitch using aerobic rather than anaerobic

Question 10

Stages of aerobic respiration and where

Accepted Answer

Glycolysis in cytoplasm
Link reaction in mitochondrial matrix
Krebs cycle in mitochondrial matrix
Oxidative phosphorylation in mitochondrial membrane

Question 11

Glycolysis

Accepted Answer

2 phosphate groups from 2ATP added to glucose (6C) forming 2 phosphorylated 3C intermediates and 2ADP -> 2x3C compounds oxidised to form 2xPyruvate, 2H reducing NAD -> phosphate groups transferred to 4ADP making 4ATP (substrate phosphorylation)

Question 12

Link reaction

Accepted Answer

Pyruvate is decarboxylated and dehydrogenated releasing CO2 and 2H which reduces NAD - the remaining 2C compound combines with Coenzyme A forming Acetyl CoA

Question 13

Krebs cycle

Accepted Answer

Acetyl CoA combines a 4C compound to create a 6C compound -> 6C decarboxylated and dehydrogenated forming a 5C, CO2, and 2H which reduces NAD -> 5C decarboxylated and dehydrogenated forming 4C, CO2, 3x2H which reduce 2NAD and FAD, and ATP -> cycle repeats

Question 14

Oxidative phosphorylation - electron transport chain

Accepted Answer

Reduced coenzymes carry 2H+ and 2e- to electron transport chain on inner membrane, coenzymes no longer reduced -> electrons pass along ETC, releasing energy to move H+ into the intermembrane space -> electrochemical gradient formed across inner membrane

Question 15

Oxidative phosphorylation - chemiosmosis

Accepted Answer

H+ diffuse back into matrix through stalked protein ATP synthase -> H+ changes active site shape allowing the enzyme to catalyse ATP synthesis ->2 H+ and 2e- recombine in the matrix forming 2H atoms which combine with 1/2O2 to form H2O

Question 16

Role of O2 in electron transport chain and why anaerobic respiration occurs

Accepted Answer

Final electron carrier, aerobic respiration cannot occur without it as electrons could not continue passing down the ETC
Anaerobic respiration occurs as without O2, reduced NAD can't be oxidised back to NAD to be used in most respiration reactions

Question 17

Anaerobic respiration

Accepted Answer

Glycolysis occurs, NAD and 2ATP to turn glucose into 2 pyruvate, 4ATP and reduced NAD
Pyruvate reduced to lactate by reduced NAD, NAD is reformed
Cycle repeats as NAD can be used in glycolysis again

Question 18

Effect of lactate build up

Accepted Answer

Lactate increases pH (by releasing H+ ions) -> negatively charged groups in active site are neutralised -> no attraction between charged groups on substrate and active site -> substrate doesn't bind and no reaction can occur

Question	Answer
How muscle, tendons, bones, and ligaments interact	2 bones joined by ligaments at a joints Synovial fluid between bones for less friction Tendons attach muscle to bone, when muscle contact the inelastic tendon pulls on the bone to move it.
Muscle structure	Muscle made up of muscle fibres joined by connective tissue Muscle fibres made up of myofibrils Myofibrils sectioned into sarcomeres Sarcomeres made up of actin and myosin
Muscle fibre structure	Myofibrils surrounded by sarcolemma, transverse tubules, and the sarcoplasmic reticulum Connected to a motor neuron at the neuromuscular junction
Sliding filament theory - receiving the impulse	Impulse reaches the neuromuscular junction and spreads through fibre via transverse tubule Ca2+ released from sarcoplasmic reticulum into sarcoplasm
Sliding filament theory - moving the actin	Ca2+ binds to troponin on actin causing it to move along with tropomyosin revealing myosin binding sites Myosin head binds to binding site releasing ADP & Pi forming cross-bridges Head changes shape, nodding forward and moving the actin over the myosin
Sliding filament theory - repeating the movement of actin	ATP binds to head causing it to detach ATPase hydrolyses ATP to ADP and Pi causing head to return to original upright position Head can now reattach to actin further back to move it more inwards Overall the sarcomere shortens contracting the muscle
Sarcomere, Actin, and Myosin	Actin is a beaded molecule containing troponin wrapped by tropomyosin Myosin is 2 polypeptides wrapped around each other with globular heads On sarcomere - light band=actin, medium band=myosin, dark band=actin and myosin overlapping
Fast and Slow twitch uses	Slow twitch = slower sustained contractions for longer periods of work - energy from aerobic respiration, requires more O2 Fast twitch = rapid, intense contractions - energy from anaerobic respiration, requires more glucose
Fast and Slow twitch structural and physiological differences	Slow twitch have: more myoglobin (O2 storing) - redder more mitochondria less sarcoplasmic reticulum less glycogen more capillaries fatigue slower (less lactate produced) Differences explained by slow twitch using aerobic rather than anaerobic
Stages of aerobic respiration and where	Glycolysis in cytoplasm Link reaction in mitochondrial matrix Krebs cycle in mitochondrial matrix Oxidative phosphorylation in mitochondrial membrane
Glycolysis	2 phosphate groups from 2ATP added to glucose (6C) forming 2 phosphorylated 3C intermediates and 2ADP -> 2x3C compounds oxidised to form 2xPyruvate, 2H reducing NAD -> phosphate groups transferred to 4ADP making 4ATP (substrate phosphorylation)
Link reaction	Pyruvate is decarboxylated and dehydrogenated releasing CO2 and 2H which reduces NAD - the remaining 2C compound combines with Coenzyme A forming Acetyl CoA
Krebs cycle	Acetyl CoA combines a 4C compound to create a 6C compound -> 6C decarboxylated and dehydrogenated forming a 5C, CO2, and 2H which reduces NAD -> 5C decarboxylated and dehydrogenated forming 4C, CO2, 3x2H which reduce 2NAD and FAD, and ATP -> cycle repeats
Oxidative phosphorylation - electron transport chain	Reduced coenzymes carry 2H+ and 2e- to electron transport chain on inner membrane, coenzymes no longer reduced -> electrons pass along ETC, releasing energy to move H+ into the intermembrane space -> electrochemical gradient formed across inner membrane
Oxidative phosphorylation - chemiosmosis	H+ diffuse back into matrix through stalked protein ATP synthase -> H+ changes active site shape allowing the enzyme to catalyse ATP synthesis ->2 H+ and 2e- recombine in the matrix forming 2H atoms which combine with 1/2O2 to form H2O
Role of O2 in electron transport chain and why anaerobic respiration occurs	Final electron carrier, aerobic respiration cannot occur without it as electrons could not continue passing down the ETC Anaerobic respiration occurs as without O2, reduced NAD can't be oxidised back to NAD to be used in most respiration reactions
Anaerobic respiration	Glycolysis occurs, NAD and 2ATP to turn glucose into 2 pyruvate, 4ATP and reduced NAD Pyruvate reduced to lactate by reduced NAD, NAD is reformed Cycle repeats as NAD can be used in glycolysis again
Effect of lactate build up	Lactate increases pH (by releasing H+ ions) -> negatively charged groups in active site are neutralised -> no attraction between charged groups on substrate and active site -> substrate doesn't bind and no reaction can occur

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Bio topic 7