SWOT with Narayankar

Q. Describe the location and structure of skeletal muscles. Ans: i. Location: Major part of skeletal muscles which move the bones do not lie on the same bone but they are located on the bone atop. e.g. Biceps and triceps that move the forearm are located in the upper arm. ii. Structure: At any joint, two types of bones are present i.e., stationary and movable. The end of the skeletal muscle to which the stationary bone is attached is called the origin whereas the opposite end attached to movable bone is called insertion. The middle thick part of the muscle is called as belly. All the fibres in a muscle do not extend from end to end and they are maximum in the middle part of the muscle. Thus, most of the large muscles are fusiform in shape. Q. Explain the types of straited muscles. Ans: On the basis of movements, striated muscles are of three types: i. Agonists: are considered as the prime movers. They bring about the initial movement of a part. E.g.: biceps. ii. Antagonists: They bring

Q. Why a red muscle can work for a prolonged period whereas white muscle fibre suffers from fatigue after a shorter work? Ans: i. Red muscle fibres contain large amount of myoglobin and mitochondria (site of aerobic respiration), whereas white muscles fibres contain lesser amount of myoglobin and mitochondria. ii. Myoglobin is an iron-containing pigment that carries oxygen molecules to muscle tissues. Abundance of these pigments in red muscle fibres supports higher rate of aerobic respiration, whereas white muscle fibres have less mitochondria and depend upon anaerobic respiration.  iii. Anaerobic respiration in muscle white fibres leads to the production of lactic acid and accumulation of higher of levels lactic acid can result in fatigue in white muscle fibres. Thus, red muscle fibres can perform prolonged work and show less fatigue due to accumulation of negligible amount loss or of lactic acid, whereas white muscle fibres suffer from fatigue after a shorter work due to accumulation

Q. What is locomotion? Ans: The change in locus of whole body of living organism from one place to another place is called locomotion. Q. State the four basic types of locomotory movements seen in animals. Ans: The four basic types locomotory movements seen in animals are: i. Amoeboid movement: It is performed by pseudopodia. e.g. leucocytes. ii. Ciliary movement: It is performed by cilia. e.g. ciliated epithelium. In Paramoecium, cilia help in passage of food through cytopharynx. iii. Whirling movement: It is performed by flagella. e.g. sperms. iv. Muscular movement: It is performed by muscles, with the help of bones and joints. Q. Movements and locomotion is necessary in animals. Give Reason. Ans: i. Movement is one of the important characteristics of all the living organisms. Animals exhibit wide range of movements like rhythmic beating of heart, movement of diaphragm during respiration, ingestion of food, movement of eyeballs, etc. ii. Locomotion results into change in place or loc

i. Location : Major part of skeletal muscles which move the bones do not lie on the same bone but they are located on the bone atop. e.g. Biceps and triceps that move the forearm are located in the upper arm. ii. Structure : At any joint, two types of bones are present i.e., stationary and movable. The end of the skeletal muscle to which the stationary bone is attached is called the origin whereas the opposite end attached to movable bone is called insertion. The middle thick part of the muscle is called as belly. All the fibres in a muscle do not extend from end to end and they are maximum in the middle part of the muscle. Thus, most of the large muscles are fusiform in shape

i. Myosin filament: a. Each myosin filament is a polymerized protein. Many meromyosins (monomeric proteins) i constitute one thick filament. b. Myosin molecule consists of two heavy chains (heavy meromyosin / HMM) coiled around each other forming a double helix. One end of each of these chains is projected outwardly is known as cross bridge . This end folds to form a globular protein mass called myosin head . c. Two light chains are associated with each head forming 4 light chains/light meromyosin / LMM. d. Myosin head has a special ATPase activity . It can split ATP to produce energy. e. Myosin contributes 55% of muscle proteins. f. In sarcomere, myosin tails are arranged to point towards the centre of the sarcomere and the heads point to the sides of the myofilament band. ii. Actin filament : It is a complex type of contractile protein. It is made up of three components: a. F actin : It forms the backbone of actin filament. F actin is made up of two helica