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Important Questions Class 11 Biology Chapter 20 Locomotion Movement

One of the most significant features exhibited by living entities is movement. Both plants and animals exhibit movement in a wide range of variety. A simple form of movement is where unicellular organisms such as Amoeba exhibits streaming of protoplasm. Other movements are the movement of flagella, cilia, and tentacles. Some movements cause to shift from one to another position which are voluntary movements termed as locomotion. Examples of locomotion are running, flying, walking, swimming, etc. Movement and locomotion are closely linked and hence studied together. All  locomotions  are movements but all movements are not locomotions. It varies in animals. Animals locomote in search of food, mate, shelter, suitable habitat, suitable climatic conditions or to escape from predators. Read onto to know more about locomotion and movement.

Q.1. List the name of the human body cell/tissues that: a) Display ameboid movement b) Display ciliary movement A.1.  a) Macrophages and leucocytes. Cytoskeletal elements such as microfilaments are involved too. b) They mostly occur in internal organs that are lined by the ciliated epithelium. Cilia in the trachea, Ciliated epithelium in the fallopian tube. Q.2. A complete coordinated activity of muscular _______, _________ systems leads to locomotion. A.2.  Skeletal system and neural systems. Q.3. Name the cell referring to sarcoplasm, sarcoplasmic reticulum, and sarcolemma. Also, list the parts of cells that refer to these names. A.3.  Each muscle cell or fibre is lined by the plasma membrane known as the sarcolemma which contains the sarcoplasm. A muscle fibre is a syncytium as the sarcoplasm possesses many nuclei. The sarcoplasmic reticulum of the muscle fibres stores calcium ions. Q.4. Mark the components of the actin filament in the diagram given below:

A.4.  Troponin, Tropomyosin, F-actin. Q.5. List the correct order of the middle ear bones called as ear ossicles starting from the eardrum. A.5.  Malleus, incus, and stapes. Q.6. State the difference between the matrix of bones and cartilage. A.6.  The matrix of bones has an inflexible material called the ossein and contains calcium salts whereas the matrix of cartilage has a flexible material, the chondrin and may or may not have calcium salts. Q.7. Where in the body is the ball and socket joint present? A.7.  They are present between the humerus and pectoral girdle – the shoulder joints, hip joints, femur bone in socket pelvic girdle. Q.8.What is locomotion? A.8.  Locomotion is the ability of an organism to move from one place to another place. Q.9. What are the different types of  locomotion in humans? A.9. Walking, running, swimming, jumping are the different types of locomotion. Q.10.How is locomotion different from the movement? A.10.  Locomotion is the displacement of a body from one place to another. On the contrary, movement is the displacement of a body or a part of the body from its original position.

Q.1. Define the following terms with respect to rib cage: a) Bicephalic ribs c) True ribs c) Floating ribs A.1.  a) Each rib has two articulating surfaces on its dorsal end and is referred to as bicephalic ribs. b) These are the first seven pairs of ribs which are ventrally attached to the sternum with the assistance of hyaline cartilage and dorsally appended to the thoracic vertebrae. c) They are the last two pair of ribs and are not attached ventrally to the sternum hence the name. Q.2. Old people usually suffer from inflamed and stiff joints, name the condition. State the reasons for the symptoms. A.2.  It is called  osteoporosis . It is an age-related disorder symbolized by diminishing bone mass and higher chances of fractures. In old-aged females, it is commonly caused due to decreasing levels in the estrogen hormones after menopause. Q.3. List two hormones causing fluctuation of Ca++ level. A.3.  Parathyroid hormone and Calcitonin. Q.4. What is Gout? A.4.  It is the inflammation of the joints which is produced due to the buildup of uric acid crystals in the synovial joints which causes movement to become painful and difficult. Q.5. What is the significance of locomotion in animals? A.5. In animals, locomotion plays an important role in helping them to move from one place to another. Animals move for many reasons to support their living. Therefore they walk, run, jump, fly, swim and to escape from their predators. Q.6. Where do muscle contractions derive their energy from? A.6.  From ATP. Every myosin molecule contains myosin ATPase, an enzyme at its head. In the presence of this enzyme along with Ca 2+ , Mg 2+  ions, the inorganic phosphate, and ADP it is disintegrated by ATP to release energy from the myosin head. This energy causes myosin to cross bridges to bind to actin. These cross-bridges that are energized, move, resulting in the sliding of thin myofilaments with the thick myofilaments, thereby causing muscle contraction.

Q.1. Does calcium ion concentration in blood cause tetany in some cases? Compare fluctuation in blood calcium with tetany. A.1.  In the regulation of muscle contraction, calcium plays a significant role. The  parathyroid hormone  (PTH) that is secreted by the parathyroid gland increases the calcium level in the blood. In hypoparathyroidism (PTH deficiency), the level of calcium in blood dips which causes an increase in the excitability of muscles and nerves resulting in convulsions and cramps. It also produces sustained contractions of the muscles of face, hands, feet, and larynx. This disorder is referred to as parathyroid tetany. Q.2. How does the slipped disc affect the lower back and overall health? A.2.  The bones are protected by the intervertebral discs that are situated in between the vertebrae. They absorb the shocks from everyday activities such as lifting, walking, and twisting. Each of the vertebral discs has two parts, one is the soft inner portion that is gelatinous and the other is a tough outer ring. In case of any weakness or injury, the inner part protrudes through the outer ring and is called as the slipped disc which can cause added pressure on the muscles and nerves surrounding it which affects the health in ways listed below:

If left untreated, the slipped disc can cause severe damage to the nerves which can be permanent. In some cases, it can cause the nerve impulses to cut off to cauda equina nerves in the legs and lower back which can result in loss of bladder control. Q.3. Describe the significance of Ca 2+  ions in the contraction of muscles. A.3.  Calcium plays a key role in the muscle contraction process. During contraction of muscles, from the motor endplate, an action potential passes over the sarcolemma and further into the T-tubules and sarcoplasmic reticulum and triggers it to produce Ca 2+  ions into the sarcoplasm. The binding of calcium ions to the troponin causes its shape and position to change which in turn modifies position and shape of tropomyosin that binds the troponin. This shift presents the active sites on the molecule, F-actin which prompts the myosin cross-bridges to bind to these active sites. Q.4. State the differences between pectoral and pelvic girdle. A.4.  Both the structures are known to provide support to the lower and upper parts of the body. Following are the differences:

  Q.5.What are the different types of movements? A.5.  Movement is a process of changing position or location. Different organisms have different types of movements. Based on the mode of locomotion, movements are of three types:

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It is called as shoulder girdle as it occurs in the shoulder region.

It is called hip girdle as it occurs in the hip region.

It is divided into two parts – One scapula and one clavicle.

One pelvic girdle is formed by two innominate bones where each bone has 3 parts – ilium, pubis, and ischium.

Not articulated with the vertebral column.

Articulated with the vertebral column.

Articulation of the axial skeleton and upper limb is brought about by the clavicle and scapula.

The innominate at its mid-lateral surface has a deep cup-shaped acetabulum where the head of the femur connects the two parts of the pelvic girdle for the formation of the pubic symphysis.

Associated bones are light and not subjected to much stress.

Associated bones are hard and subjected to much stress.

Functions – standing, running, jumping, etc.