Summary Edexcel Biology A Level (Salters Nuffield A) Topic 7 - Run for your Life - Full Notes
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Course
Topic 7 (9BN002)
Institution
PEARSON (PEARSON)
Detailed and comprehensive notes on topic 7 (run for your life) of Edexcel biology A Level. Covers (skeletal) muscle, sliding filament theory, aerobic respiration, anaerobic respiration, heart rate, electrical activity in the heart, breathing, spirometry, homeostasis, thermoregulation, exercise, me...
Exercise ............................................................................................................................................. 23-25
Health and Exercise ........................................................................................................................................................................................ 23
Medical Technology........................................................................................................................................................................................ 24
Performance-Enhancing Drugs ................................................................................................................................................................. 25
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,Specification
7.1 Know the way in which muscles, tendons, the skeleton and ligaments interact to enable movement,
including antagonistic muscle pairs, extensors and flexors (P4).
7.2 Understand the process of contraction of skeletal muscle in terms of the sliding filament theory,
including the role of actin, myosin, troponin, tropomyosin, calcium ions (Ca2+), ATP and ATPase
(P6-7).
7.3 i) Understand the overall reaction of aerobic respiration as splitting of the respiratory substrate,
including glucose, to release carbon dioxide as a waste product and reuniting of hydrogen with
atmospheric oxygen with the release of a large amount of energy (P8).
ii) Understand that respiration is a many-stepped process, with each step controlled and catalysed by
a specific intracellular enzyme (P8).
7.4 Understand the roles of glycolysis in aerobic and anaerobic respiration, including the
phosphorylation of hexoses, the production of ATP, reduced coenzyme, pyruvate and lactate (details
of intermediate stages and compounds are not required) (P9).
7.5 Understand the role of the link reaction and the Krebs cycle in the complete oxidation of glucose and
formation of carbon dioxide (CO2), ATP, reduced NAD and reduced FAD (names of other
compounds are not required) and why these steps take place in the mitochondria, unlike glycolysis
which occurs in the cytoplasm (P10).
7.6 Understand how ATP is synthesised by oxidative phosphorylation associated with the electron
transport chain in mitochondria, including the role of chemiosmosis and ATP synthase (P11).
7.7 Understand what happens to lactate after a period of anaerobic respiration in animals (P12).
7.8 i) Know the myogenic nature of cardiac muscle (13).
ii) Understand how the normal electrical activity of the heart coordinates the heart beat, including the
roles of the sinoatrial node (SAN), the atrioventricular node (AVN), the bundle of His and the
Purkyne fibres (P13).
iii) Understand how the use of electrocardiograms (ECGs) can aid the diagnosis of cardiovascular
disease (CVD) and other heart conditions (P15).
7.9 i) Know how to calculate cardiac output (P14).
ii) Understand how variations in ventilation and cardiac output enable rapid delivery of oxygen to
tissues and the removal of carbon dioxide from them, including how the heart rate and ventilation
rate are controlled and the roles of the cardiovascular control centre and the ventilation centre in the
medulla oblongata (P14 & P16).
7.10 i) Know the structure of a muscle fibre (P5).
ii) Understand the structural and physiological differences between fast and slow twitch muscle
fibres (P5).
7.11 Understand what is meant by negative feedback and positive feedback control (P19).
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,Specification
7.12 Understand homeostasis and its importance in maintaining the body in a state of dynamic
equilibrium during exercise, including the role of the hypothalamus and the mechanisms of
thermoregulation (P19 & P21-22).
7.13 Understand the analysis and interpretation of data relating to possible disadvantages of exercising too
much (wear and tear on joints, suppression of the immune system) and exercising too little
(increased risk of obesity, cardiovascular disease (CVD) and diabetes), recognising correlation and
causal relationships (P23).
7.14 Understand how medical technology, including the use of keyhole surgery and prostheses, is
enabling those with injuries and disabilities to participate in sports (P24).
7.15 Be able to discuss different ethical positions relating to whether the use of performance-enhancing
substances by athletes is acceptable (P25).
7.16 Understand how genes can be switched on and off by DNA transcription factors including hormones
(P20).
CORE PRACTICAL 16:
Investigate rate of respiration practically.
CORE PRACTICAL 17:
Investigate the effects of exercise on tidal volume, breathing rate, respiratory minute ventilation and oxygen
consumption using data from spirometer traces.
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,Muscles and Movement
7.1 Know the way in which muscles, tendons, the skeleton and ligaments interact to enable movement,
including antagonistic muscle pairs, extensors and flexors.
Joint Structure
Skeletal Muscle
7.1 Know the way in which muscles, tendons, the skeleton and ligaments interact to enable movement,
including antagonistic muscle pairs, extensors and flexors.
• Skeletal Muscle (Striated Muscle): The type of muscle attached to the bones by tendons for
movement.
• Flexor: A muscle that bends a joint when it contracts, e.g. biceps.
• Extensor: A muscle that straightens a joint when it contracts, e.g. triceps.
• Antagonistic Pair: Two muscles that work together to move a bone to and fro.
• Muscles work in pairs because they can only pull (when they contract) – they cannot push.
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, Skeletal Muscle
7.10 i) Know the structure of a muscle fibre.
ii) Understand the structural and physiological differences between fast and slow twitch muscle
fibres.
Muscle Fibres
• Muscle Fibres: Large bundles of
long cells which make up skeletal
muscle.
• Muscle fibres are multinucleate and
have lots of mitochondria to produce
ATP.
• Sarcolemma: The cell membrane of
muscle fibres.
• Sarcoplasm: The cytoplasm of
muscle cells.
• Sarcoplasmic Reticulum:
Intracellular membranes within the
sarcoplasm that store and release
Ca2+ ions for muscle contraction.
• Transverse (T) Tubules: Sections
of sarcolemma that fold inwards
across the muscle fibre to help
spread electrical impulses through
the sarcoplasm.
• Myofibrils: Long, cylindrical
organelles made of proteins and are
highly specialised for contraction.
• Sarcomere: Basic, repeating unit of
a muscle fibre.
Slow Twitch Fibres Fast Twitch Fibres
Muscle fibres that contract slowly Muscle fibres that contract very quickly
Muscles used for posture Muscles used for fast movement
Good for endurance activities Good for short bursts of speed and power
Can work for long time without getting tired Get tired very quickly
Energy is released quickly through anaerobic
Energy is released slowly through aerobic respiration
respiration
Lots of mitochondria and blood vessels to supply
Few mitochondria or blood vessels
muscles with oxygen for aerobic respiration
Rich in myoglobin (reddish in colour) Little myoglobin (whitish in colour)
Low glycogen content High glycogen content for anaerobic respiration
Extensive sarcoplasmic reticulum for rapid, repeated
Little sarcoplasmic reticulum
muscle contraction
• Myoglobin: Red protein containing haem, which carries and stores oxygen.
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