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MUSCLES AND ENERGY SYSTEMS 1. Most muscles in the body work in pairs in what is known as the “agonist-antagonist relationship”. Provide three examples of muscle pairs that clearly display the agonist antagonist relationship. Biceps & Triceps; Quadriceps & Hamstrings; Gastrocnemius & Tibialis Anterior; Abdominals & Erector Spinae 2. The following diagram shows a sacromere, which is the basic unit of all muscles. Clearly label the: I-band; A-band; H-zone; Actin filaments; Myosin filaments and Myosin crossbridges. 3. What are some differences between “anaerobic glycolysis” and “aerobic glycolysis”? Aerobic glycolysis = sufficient oxygen to break down glycogen aerobically (typically using the aerobic energy system) with tolerable by products such as CO2 and H2O. Exercise can continue for extended periods until glycogen stores start to deplete 2/3 hours.. Anaerobic glycolysis = insufficient oxygen to break down glycogen aerobically (typically using the Lactic Acid system) with toxic by product being lactic acid. Exercise intensity must drop to allow more oxygen to be supplied to enable some lactic acid to be broken down. 4. Complete the following table by providing three examples of sporting activities that predominantly use fast twitch and slow twitch fibres: Sporting Examples Fibre Type Fast twitch 1. 2. 3. Slow Twitch 1. 2. 3. Sporting Examples Fibre Type Fast twitch Slow Twitch 100m sprint Basketball rebound/lay-up Shot Put Javelin Overhead mark in football (must be explosive) Marathon Archery Cross country Skiing Endurance swimmers (English Channel) Distance runners (must be extended nature) 5. What is the anaerobic threshold and at what stage is it reached? The anaerobic threshold is the point during exercise when lactic acid begins to accumulate. This is commonly accepted to occur when exercise intensity exceeds 85% max heart rate. This can be increased up to a maximum value of 90% max heart rate as a result of extended aerobic training. 6. What are some symptoms that lactic acid has built up in our muscles? Symptoms are “felt”: heaviness of limbs; pain; numbness/jelly-like feeling of limbs 7. List three foods that are sources of protein: 1. ____________ 2. ________ 3. _________ Outline what major function they have in our bodies (other than energy supply). Foods high in proteins – fish & red meats & beans & eggs & dairy products and major function they have in our bodies include growth & repair of cells; hormone and enzyme production. 8. Graph One Graph 2 Explain the type of exercise that could be exhibited in Graph One and Two. Justify your reasoning. Graph One – is a 100 metre sprinter – the first 5 secs are powering the muscles with ATP and then the second part of the anaerobic system (the lactic acid system) powers the last 5 seconds. Note that the aerobic system is also contributing 30% of the athlete’s energy requirements by the 7th second. Graph Two –student 800metre run– it must be clearly discussed that the PC system is used initially and depletes (5-10 seconds). The lactic acid system increases its contribution as the PC system is decreasing in its contribution and the aerobic system is slowly building up to become the major energy contributor by the 30-40 second mark of the activities. The longer the events go, the more heavily reliant upon the aerobic system performers become. Students should discuss the interplay of the 3 systems at any one point of the activity. 9. During exercise, the tissue of muscles can go into oxygen debt. Cramping occurs due to a build up of lactic acid. The build up of lactic acid occurs because there is not enough oxygen to facilitate the entire process of cellular respiration. As a result, glycolysis only occurs. The following graph records changes in the blood composition of various substances of a subject during and after exercise. Time 1 2 3 4 Account for the shape of each graph, with respect to before, during and post exercise levels. Before Exercise(1): Glucose stores will be high – in preparation for activity; by products of exercise will be low (e.g. low levels of lactic acid and pyruvic acid) During Exercise; Glucose levels will be depleting and by products of anaerobic glycolysis will be increasing – e.g. time 2 – note levels of lactic acid and pyruvic acid. Post Exercise: Activity has become aerobic and then ceased at Time 3. Note glucose levels are recovering and other levels are also back to pre-exercise levels. DIGESTION, DIET AND NUTRITION Enzymes 1. Enzymes are protein substances that act as catalysts. What does a catalyst do? _______________increase reaction rate 2. What is an enzyme? protein molecules that bind with substrate chemicals and facilitate their break-down ________________________________________________________ 3. What are substrates? The target chemical to which the enzyme will bind e.g. the food – carbohydrate ____________________________________________________________ 4. What are active sites? The target area where the substrate and the enzyme join – often described as a lock and key model 5. How are enzymes named? They are named after their host substrate ____________________________________________________________ 6. Identify the enzymes in the following table Substrate Sucrose Maltose Lactose Carbohydrates Lipids Proteins 7. Enzyme Sucrase Maltase Lactase Carbohydratase e.g. amylase Lipase Protease e.g. pepsin What impact does heat have on enzymes? High temperatures denature (break the chemical bonds between the amino acids in the protein) the protein ____________________________________________________________ 8. The rate of a reaction can be increased by increasing the temperature of the reaction mixture. A catalyst is a substance which can increase the rate of a reaction but is not used up during the reaction. Some catalysts are simple chemicals. Others such as enzymes are complex proteins. Enzymes cannot function as catalysts at high temperatures. Most enzymes are unusable (denatured) above 50°C. The same chemical reaction was set up in four beakers. The type of catalyst and the temperature are shown in the table. In this case the catalyst increased the rate of reaction. A) In which beaker would the fastest reaction occur? Y B) Justify your answer. The highest temperature will increase the molecular motion of the reaction – therefore facilitating a greater number of potential enzymesubstrate complexes. Note that Z is incorrect as the enzyme would denature at this temperature and it would be therefore ineffective Digestion 9. Label the digestive system pictured below and outline the function of these organs. 10. A healthy woman drank 100 cm3 of a glucose solution at time t. Which graph shows the likely changes in her blood glucose level? Graph D – show gradual reabsorption of glucose from the digestive system after time t. . SKELETON AND JOINTS 1. Label 7 bones from the Skeleton diagram below 2. A newborn baby has 305 bones. By age 25, the average adult skeleton has 206 bones. What term explains this process? Bone Fusing http://www.bbc.co.uk/science/humanbody/body/factfiles/bonegrowth/femur.shtml 3.. . Explain how both of these joint systems operate. Include information about their possible location in the body; their range of movement; their advantages and disadvantages. Ball and socket joint – 3 dimensional movement; located at shoulder and hip; not as strong as a hinge joint – allows for a diverse range of movements Hinge Joint – 2 dimensional movement; located at knee and elbow; very strong 3b. The diagram below shows a model of a movable joint: Key : direction of possible movements Which of the following description about the joint is right? Directions : A. B. Type of joint represented by the model hinge joint hinge joint Example elbow joint hip joint C. ball and socket joint shoulder joint D. ball and socket joint knee joint Questions 4 to 6 refer to the diagram below which shows some of the bones, muscles and tendons of the human arm : 4. Tendon R is attached to bone S at position 3 rather than at position 4. This arrangement has the advantage that A. less energy would be required for raising a load. B. the forearm can move faster when muscle Q contracts. C. the joint would not be dislocated easily. D. muscle Q works antagonistically with muscle P. 5. What will happen when muscle P contracts? A. Muscle P becomes thinner. B. Muscle Q becomes shorter. C. Bone S is raised up. D. The elbow joint is extended. 6. Cartilage is present at A. position 1. B. position 2. C. position 3. D. position 4. 7. Which of the following statements about skeletal muscles are correct ? (1) They are connected to bones by ligaments. (2) Their actions can be controlled by will. (3) They can carry out aerobic and anaerobic respiration at the same time. A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3) BIOMECHANICS 1. Outline the 12 steps of muscular contraction. Let's take a look at what occurs within a skeletal muscle, from excitation to contraction to relaxation: 1.An electrical signal (action potential) travels down a nerve cell, causing it to release a chemical message (neurotransmitter) into a small gap between the nerve cell and muscle cell. This gap is called the synapse. 2.The neurotransmitter crosses the gap, binds to a protein (receptor) on the muscle-cell membrane and causes an action potential in the muscle cell. 3.The action potential rapidly spreads along the muscle cell and enters the cell through the T-tubule. 4.The action potential opens gates in the muscle's calcium store (sarcoplasmic reticulum). 5.Calcium ions flow into the cytoplasm, which is where the actin and myosin filaments are. 6.Calcium ions bind to troponin-tropomyosin molecules located in the grooves of the actin filaments. Normally, the rod-like tropomyosin molecule covers the sites on actin where myosin can form crossbridges. 7.Upon binding calcium ions, troponin changes shape and slides tropomyosin out of the groove, exposing the actin-myosin binding sites. 8.Myosin interacts with actin by cycling crossbridges, as described previously. The muscle thereby creates force, and shortens. 9.After the action potential has passed, the calcium gates close, and calcium pumps located on the sarcoplasmic reticulum remove calcium from the cytoplasm. 10. As the calcium gets pumped back into the sarcoplasmic reticulum, calcium ions come off the troponin. 11. The troponin returns to its normal shape and allows tropomyosin to cover the actinmyosin binding sites on the actin filament. 12. Because no binding sites are available now, no crossbridges can form, and the muscle relaxes. http://health.howstuffworks.com/muscle3.htm 2. There are 3 classes of levers. Draw a diagram to clearly show the three different placements of the force/effort; axis/fulcrum and resistance/load in each class of lever. 1st Class Lever first-class lever is a lever in which the fulcrum is located in between the input effort and the output load. In operation, a force is applied (by pulling or pushing) to a section of the bar, which caues the lever to swing about the fulcrum, overcoming the resistance force on the opposite side. The fulcrum may be at the center point of the lever as in a seesaw or at any point between the input and output. This supports the effort arm and the load. Examples: 1. Seesaw (also known as a teeter-totter) 2. moving the head front to back 2nd Class Lever In a second class lever the input effort is located at one end of the bar and the fulcrum is located at the other end of the bar, opposite to the input, with the output load at a point between these two forces. Examples: 1. Nutcracker 2. Door 3. Foot ankle 3rd Class lever It is to be noted that for this class of levers, the input effort is higher than the output load, which is different from the first-class and second-class levers. However, also notice that the input effort moves through a shorter distance than the load. Thus it still has its uses in making certain tasks easier to do. Third class levers use the effort in between the output load on one side and the input on the opposite end. Examples: 1. Human Arm 2. Tweezers 3. (i) What is elasticity? the tendency of a body to return to its original shape after it has been stretched or compressed (ii) Why will a tennis ball bounce more on a “rebound ace” surface such as that found at Rod Laver Arena (Melbourne) compared to a ball bounced on the grass courts of Wimbledon? Both the surface and the ball would have elasticity and therefore this effect is compounded – polyurethane – synthetic rubber base 5. The diagram below shows a man swimming in water : What are the conditions of his arm muscles at this posture ? Directions : elbow joint: Left arm Biceps Triceps Right arm Biceps Triceps A. B. C. D. contracted relaxed relaxed contracted relaxed contracted relaxed contracted relaxed contracted contracted contracted relaxed relaxed relaxed contracted Questions 6 and 7 refer to the model below which illustrates the movement at the Key : P and Q are rubber bands R and S are wooden planks 6. What will happen when Q is shortened ? A. B. C. P shortened shortened stretched S raised lowered raised D. stretched lowered 7. This model is designed to demonstrate A. the movement of the forearm. B. the movement of the elbow joint. C. the effect of muscular contraction. D. the action of antagonistic muscles. NERVOUS SYSTEM 1. Label the Neuron Read the definitions, then label the neuron diagram below. axon - the long extension of a neuron that carries nerve impulses away from the body of the cell. axon terminals - the hair-like ends of the axon myelin sheath - the fatty substance that surrounds and protects some nerve fibers node of Ranvier - one of the many gaps in the myelin sheath - this is where the action potential occurs during saltatory conduction along the axon cell body - the cell body of the neuron; nucleus - the organelle in the cell body of the neuron it contains the nucleus (also called the that contains the genetic material of the cell soma) Schwann's cells - cells that produce myelin - they are dendrites - the branching structure of located within the myelin sheath. a neuron that receives messages (attached to the cell body) 2. The myelin sheath along the axon serves an important function in the transmission of messages through-out the nervous system. Describe the problems that could occur if the sheath were to break-down (denature) over time. Electrical message could either be send to the wrong effector organs (e.g. muscles) or might not make their destination – demylinating disease – multiple sclerosis 3. Draw a labelled diagram to explain nerve-muscle junction. http://www.bishopstopford.com/faculties/science/arthur/synapse.swf