RBSE Solutions For Class 12 Biology Chapter 30: Movements and Locomotion in Man | Textbook Important Questions & Answers

RBSE Class 12 Biology Chapter 30 – Movement and Locomotion in Human. In this chapter, students can learn in detail about the skeleton system in humans, different types of the skeleton, cartilages and bones, joints, types of joints, muscles, types of muscles, structure and functions of skeletal system and role of muscles and bones in the locomotion. It also includes a detailed study about the muscle fibres functions of voluntary and involuntary muscles, their differences, mechanism of muscle contractions, disorders of bones and much more.

These important questions help students to perform exceptionally well in their exams. By practising these important questions, students can analyse their preparation, get a thorough knowledge about all the important terminologies and perform their best in the examinations.

RBSE Solutions for Class 12 are the best study material for both class assignments and other board examinations. By practising these important questions, students can gain deep knowledge about the topics explained in this chapter and also help them to be well prepared for their upcoming examinations.

RBSE Class 12 Biology Chapter 30 Important Questions

RBSE Biology Chapter 30: MCQ Type Questions

Q.1. Which of the following ions is essential for the binding of transverse bridges.

(a) Calcium

(b) Sodium

(c) Iron

(d) Potassium

Sol: (a) Calcium.

Q.2. Storage of which substance in an anaerobic contraction of muscles become painful

(a) Calcium ion

(b) Myosin

(c) Lactic acid

(d) Creatine phosphate.

Sol: (c) Lactic acid

Q.3. The number of bones in the hindlimb of a human is ________.

(a) 14

(b) 24

(c) 26

(d) 30

Sol: (d) 30.

Q.4. Contractile protein is ________.

(a) Troponin

(b) Myosin

(c) Tropomyosin

(d) All of the above

Sol: (b) Myosin.

Q.5. Type of elbow joint is ________.

(a) Synarthrosis joint

(b) Hinge joint

(c) Pivot joint

(d) Amphiarthrosis joint

Sol: (b) Hinge joint

Q.6. According to the sliding filament theory, the molecules decrease the length of the muscles during the muscle contraction is ________.

(a) Collagen

(b) Actin

(c) Myosin

(d) Titin

Sol: (b) Actin

Q.7. The reason for the pendular movement of cilia is________.

(a) Gliding of microtubules

(b) Contraction of microfibrils

(c) Elongation of cell wall

(d) Changes in turgidity

Sol: (b) Contraction of microfibrils

Q.8. Which of the following are the functions of the skeleton?

(a) Protection of soft organs

(b) Formation of blood corpuscles

(c) Provides space for muscle attachment

(d) All of the above.

Sol: (d) All of the above.

Q.9. The exoskeleton of an animal is ________.

(a) Skull

(b) Ribs

(c) Nails

(d) Sternum

Sol: (c) Nails.

Q.10. Matrix of a bone is of which protein.

(a) Chondrin

(b) Ossein

(c) Fibrin

(d) Retin in

Sol: (b) Ossein

RBSE Biology Chapter 30: Short Answer Type Questions.

Q.1. What is the skeleton system?

Sol. The human skeletal system serves as a framework for the human body. It consists of 206 bones and also includes tendons, ligaments and cartilage that connect the bones.

Q.2.What are the bones?

Sol. Bones are the specialized forms of connective tissues which are composed of cells embedded within an extracellular matrix. They are a highly rigid connective tissue that forms the skeleton of vertebrates. Bones are the type of tissues, comprising the blood vessels and different types of cells. Overall a newborn baby will have around 300 bones and is reduced to 206.

Q.3. What is the structural and functional unit of the muscle?

Sol. Sarcomere, the complicated unit of striated muscle tissue is the structural and functional unit of the muscle

Q.4. Which structure joins muscles with the bone?

Sol. Tendon, a tough band of fibrous connective tissue connects or joins the muscles with the bone.

Q.5. What is the primary function of the human skeleton system?

Sol. The human skeletal system provides support to the body as well as it protects the different organs of the human body.

Q.6. What is a ligament?

Sol. A ligament is the fibrous connective tissue that connects the bone joints to the bone.

Q.7. What are the different types of Joint?

Sol. There are 3 different types of Joints and are classified mainly based on their mobility:

1. Fibrous Joints or Fixed Joints
2. Synovial Joints or Freely Movable Joints
3. Cartilaginous Joints or Slightly Moveable Joints.

Q.8. What is Osteoarthritis?

Sol. Osteoarthritis is a type of joint disease that is caused by aging joints, injury and obesity. It affects the entire joint, including the cartilage, joint lining, ligaments and bone. It is usually referred to as “wear and tear” of the joints.

Q.9. What is sacrum? How many vertebrae form sacrum bone in humans?

Sol. The sacrum is a wedge-shaped bone that is below the fifth lumbar vertebrae at the base of your spine. A sacrum bone in humans is made up of five vertebrae.

Q.10. How many bones participate in the formation of a human skull?

Sol. The human skull is generally composed of 28 to 29 bones, which includes parietal, temporal, frontal, occipital, ethmoid and sphenoid.

Q.11. What are the functions of the joints?

Sol. The primary functions of Joints are to connect bones within our body. Apart from this, it also helps us to move, rotate and also bear weight.

Q.12.What is Exoskeleton?

Sol. The hard part present outside the body which protects the soft tissues and muscles is called the exoskeleton. It is developed from ectoderm and is mostly called a non-living structure. Some examples of the exoskeleton are hair, feather, scales, horns, etc.

Q.13. Which type of energy transfer occurs in the muscular functions?

Sol. In muscular functions, the chemical energy is transferred into mechanical energy.

Q.14.What is the primary function of bones in the human skeleton system?

Sol. It plays an important role in protecting the internal organs of our body, provides structural support and surfaces for the muscle attachment, stores minerals and protects the internal organs of the body.

Q.15.What are the joints?

Sol. Joint can simply be defined as the point or the location within the body where two or more bones meet together.

Q.16. What is cartilage?

Sol. Cartilage is thin, fibrous and a flexible connective tissue. It is mainly found in the external parts of the ear, larynx, respiratory tract, and the articulating surface of the joints. The cartilages lack blood vessels, which results in the slower growth and development of these tissues, compared to the other tissues.

Q.17. What are the different types of Joints?

Sol. A human skeletal system consists of four different types of Joints:

• Ball And Socket Joint.
• Pivotal Joint.
• Hinge Joint.
• Fixed Joint.

Q.18. What is Arthritis?

Sol. Arthritis is a different type of joint pains or joint disease, which is a very common disease found in almost all age groups and sexes. There are more than 100 types of identified arthritis.

Q.19.What are vertebrae?

Sol. The site or a region where bones are located within the vertebral column are called the vertebrae. There are several different types of vertebrae found within the vertebrates.

Q.20. What is Endoskeleton?

Sol. The hard part which is the internal support of the structure is called an endoskeleton. It is developed from endoderm and is called a living structure. Some examples of endoskeleton are cartilage, bone, etc.

RBSE Biology Class 12: Long Answer Type Questions

Q.1. Write the difference between Bone and Cartilage.

Sol. Difference between Bone and Cartilage:

Q.2. Write a note on the sternum

Sol. The sternum is a long flat bone located in the central part of the chest, hence it is also called the breast bone.

It forms a respiratory basket along with the rib and thoracic vertebrae.

It is a flat bone, which has a distinct flat anterior and posterior side. It is present on the midventral side of the thoracic region of the body. Ribs are found attached or joined with its lateral side.

The sternum comprises three main parts:

1. Manubrium: The upper part, which consists of the clavicle and rind that are found attached to the manubrium.
2. Sternum body: It is the middle part, which consists of second, third, fourth, fifth, sixth and seventh ribs in it. These ribs are attached to the Sternum body. It is also called Gladiolus.
3. Xiphoid process: It is the posterior part, small and a triangular plate. It is also called Ensiform.

Q.3. What are the skeletal muscles?

Sol. The skeletal muscles are also called voluntary muscles. These muscles are under the control of the human body. The skeletal muscles are present in the different parts of the body such as the body wall, legs, neck, face, etc. They are also found attached to bones through the tendons. These tendons help in different movements of the body parts and skeleton. These muscle fibres, when seen under the microscope, are in the form of stripes, which are also called striated muscles. These skeletal muscles are mainly responsible for the movement and locomotion in the human body.

Q.4. What are the different types of cartilages?

Sol. There are three different types of cartilages and it includes:

1. Hyaline cartilage: It serves as a shock absorber and allows the smooth movement of the bones at joints. They are mainly found in the nose, respiratory tract and joints
2. Fibrocartilage is found in the knee, and it is tough and inflexible.
3. Elastic cartilage is found in the ear, epiglottis, and larynx. It is the most flexible cartilage.

Q.5. What are the bones? Explain the types of bone.

Sol. Bones are the specialized forms of connective tissues which are composed of cells embedded within an extracellular matrix. They are a rigid connective tissue that forms the skeleton of vertebrates.

The bones in the human skeletal system are divided into three types:

Membranous or Investing bones.

• They are formed by the ossification in the membranes situated below the embryonic skin.
• They invest soft cartilaginous parts of the skeleton and provide them with strength.
• Flat bones of the skull, bones of digits and clavicle are examples of membranous or investing bones.

Cartilaginous or Replacing bones.

• It is formed in the place of hyaline cartilage.
• The matrix of the cartilage is destroyed by special osteoclasts.
• Bones of limbs, vertebral column and some bones of the skull are examples of cartilaginous or replacing bones.

Sesamoid bones.

• It is formed by the ossification in the ligament.
• Patella’s bone is an example of sesamoid bones.

Q.6. What is the skeletal system? What are the functions of the skeleton?

Sol. The human skeletal system serves as a framework for the human body. It consists of 206 bones and also includes tendons, ligaments, and cartilage that connects the bones.

Functions of the Skeleton.

• The skeleton forms a rigid framework and supports the body.
• The skeleton provides a base for the attachment of muscles.
• The skeleton is also involved in the production of red blood corpuscles in the bone marrow.
• The skeleton acts as a lever during various movements of the body and also helps in locomotion and movements.
• The skeleton protects a number of delicate organs, such as the brain, heart, lungs, spinal cord, etc.

Q.7. What is pelvic girdle? Draw a neat labelled diagram of the pelvic girdle.

Sol. The pelvic girdle is a ring-like bony structure, located in the lower part of the trunk. It connects the axial skeleton to the lower limbs.

Structure of a Pelvic Girdle

Q.8. Write the difference between Ligament and Tendon.

Sol. Tendons and Ligaments are an integral part of locomotion in all higher organisms. They are composed of living cells and contain plenty of collagen.

Difference between Ligament and Tendon.

Q.9. Brief out the causes and symptoms of Osteoporosis.

Sol. Osteoporosis is a condition that deteriorates the bones and makes it brittle due to low bone mass and loss of bone tissue.

Causes of Osteoporosis

Osteoporosis can be caused due to a variety of reasons such as:

• Low calcium diet
• Lack of Vitamin D
• Anorexia nervosa
• Smoking cigarettes
• Hormonal imbalance
• Low peak bone mass
• Diseases Kidney diseases
• Surgical removal of ovaries
• Drinking alcohol frequently
• Thyroid disorders such as hyperthyroidism
• Low estrogen and testosterone levels in women and men.

Symptoms of Osteoporosis

There are no visible symptoms or signs, during the beginning stages of osteoporosis. The signs and symptoms develop with time. Listed below are the few symptoms of osteoporosis.

• Broken Hips
• Back pain
• Height loss
• A stooped posture.
• Broken wrists
• Fractures of the long bones
• Acute and chronic pain of the bones.

Q.10. How does a muscle get stimulated for contractions?

Sol. Excitation for muscle contraction.

1. Nerve impulse promotes the release of neurotransmitter Acetylcholine at the ends of the axon near the neuromuscular junction.
2. This chemical changes permeability in the plasma membrane of the muscles towards Na+.
3. Due to this, Na+ enters into the muscle cells and causes a change in charge, which is positive inside the plasma membrane.
4. In normal conditions, there is a negative charge inside the inner surface of the plasma membrane.
5. The positive change is transferred on the whole plasma membrane of muscles and generates an action potential. which is known as the excitation state of muscles.

Q.11.What is the source of energy required for muscle contraction?

Sol. Energy Sources for Contraction:

• Both muscle contraction and relaxation requires energy and the main source of energy is the ATP – Adenosine Triphosphate.
• The creatine -phosphate found in the muscles provides energy instantly because it has one high energy bond, which is called the phosphagen. This process is catalysed by an enzyme creatine kinase.
• The energy required in the muscle contraction is obtained by oxidation of glucose but due to the deficiency of oxygen, this source fails to provide energy for a long period. Hence, the fermentation of the glycogen is the long-lasting source of the energy for muscle contraction.
• Glycogen fermentation results in the formation of lactic acid. This lactic acid is transported into the liver by the blood. In the liver, 80 per cent of the lactic acids are recovered into the glycogen and the remaining 20 per cent of the lactic acids are oxidized into CO2 and H2, through which energy is released. This energy is used in the process of gluconeogenesis.

Q.12. Brief of the structure and significance of the girdles.

Sol. A girdle is a tight-fitting undergarment that supports the lower body.

Pectoral girdle:

The main importance of pectoral girdle in human anatomy is it supports forelimbs and protects chest organs. The structure of pectoral girdle includes:

1. Pectoral girdle comprises two equal halves.
2. Each half has a clavicle and a scapula- coracoid bone.
3. The clavicle is a rod-like bone, which is also called the collarbone.
4. The scapula is a broad and flat bone which is found in all mammals.
5. The coracoid is fused with the scapula and found in the form of a coracoid process.
6. The supra scapula is absent in the pectoral girdle of man.
7. The dorsal side of the scapula has a spine. The anterior and ventral extension of the spine is called an acromial process.
8. The posterior process of the acromial in the rabbit is called the acromion process.
9. The head of the scapula -coracoid has a cavity called the glenoid cavity
10. The head of the humerus bones articulates to the glenoid cavity.

Pelvic Girdle

The main importance of pelvic girdle in human anatomy is it supports the hind limbs. The structure of pelvic girdle includes:

1. It comprises two equal halves and each half is called the Os-innominate.
2. Both of the Os-innominate remains united by the pubic symphysis, which is composed of fibrous cartilage.
3. Each Os-innominate has three parts: the ilium, ischium, and the pubis.
4. These three parts participate in the formation of the acetabulum.
5. There is an obturator foramen between pubis and ischium bones.

Q.13. What is the Sliding Filament Theory?

Sol. Muscles are specialized tissues having the property of elasticity, where each muscle has innumerable muscle fibres. Muscle fibres successively have thin and tiny strands called myofibrils. For movement, muscles need to contract. It contracts when tension-generating sites within the muscle fibres are activated. This mechanism is explained by the sliding filament theory.

The Sliding Filament Theory

1. This theory suggested the mechanism of contraction of striated muscles, actin and myosin filaments to be precise, which overlap each other resulting in the shortening of the muscle fibre length.
2. Actin (thin) filaments combined with myosin (thick filaments) conduct cellular movements.
3. The process of muscle contraction can be explained with the help of sliding filament theory, which was given by A.F.Huxley, J.Hensen and H.E.huxley.
4. According to this theory, the myosin filaments remain stationary and the actin filaments slide over the myosin with the help of cross-links.
5. During the contraction, the length of the A-band remains unchanged but the length of the I-band and H-zone get reduced.
6. In H-zone, the actin filaments slide over each other.
7. The contraction results in the shortening of the sarcomere.
8. The relaxation of the muscle involves reverse sliding of the actin filaments to obtain an original position.

Diagrammatic representation of the sliding filament theory.

Q.14.Brief out the causes and symptoms of Osteoarthritis

Sol. Osteoarthritis is a type of joint disease that is caused by the injury to the joints, aging of the joints and obesity. It is usually called the “wear and tear” of the joints, which affects the entire joint, including the joint lining, cartilage, ligaments, and bone.

Causes Osteoarthritis

Osteoarthritis is believed to be caused by mechanical stress on the joints and low-grade inflammatory processes. It is also related to the age of the person as the joints become weak and less dense. It usually happens gradually over time. Some risk factors that might lead to it include:

• Ageing
• Joint injury
• Overweight
• A genetic defect in joint cartilage
• An improper formation of the joints
• Stress on the joints owing to specific jobs and playing sports.

Symptoms Osteoarthritis

The symptoms of osteoarthritis develop slowly and become worse with time. The common signs and symptoms of osteoarthritis are:

• Stiffness in the joints
• Tenderness of the joints
• Loss of flexibility of the joints
• Joints pain during or after movement.
• Crackling or popping sensations under the joints.
• Swellings found around the joints, which is caused by the inflammation of the soft tissue.
• Bone spurs. These extra bits of bone, which feel like hard lumps, can form around the affected joint.

Q.15. Describe the physiology of muscle contraction.

Sol. Muscles are fibres which cause movement in our body. They also enable the functioning of our internal organs. Specialists claim that a human body has around 650 muscles, skeletal muscles to be precise.

The process of muscle contraction and relaxation involves four different phases.

Excitation of the muscles.

1. Nerve impulse promotes the release of neurotransmitter Acetylcholine the ends of the axon at the neuromuscular junction.
2. This chemical changes permeability in the plasma membrane of the muscles towards Na⁺. Due to this, the Na⁺ enters into the muscle cells and causes a change in charge, which is positive inside the plasma membrane. In normal conditions, there are negative charges inside the inner surface of the plasma membrane.
3. This positive change is transferred to the whole plasma membrane of the muscles and generates an action potential, which is known as the excitation state of muscles.

Excitation – Contraction Coupling.

1. This is the process in which action potential promotes contraction in muscle cells. This action potential instantly transfers to the T-system.
2. Due to this potential, Ca⁺⁺ is released from the sarcoplasmic reticulum and joins with troponin C.
3. It results in the configurational changes in Troponin atoms.
4. As a result, tropomyosin and troponin, both are related to the active site of actin.
5. As soon as the active site is made free, the myosin filaments join with actin and the contraction process in the muscles begin.

Contraction of the muscles.

1. The contraction of the muscles occurs by sliding filament processes, which is initiated by joining of actin and myosin transverse bridge. Just before joining the active filaments at the active site, one atom of the ATP joins at the head of the transverse bridge. Atp present in myosin head breaks down into ADP + Pi by ATPase. The ADP+ Pi remains attached or joined with the head after that myosin head joins with the active site of the actin filament.
2. There are conformational changes in the head due to the joining of the head and active site. Due to this, there is bending in the head and actin filaments are pulled towards the centre of the sarcomere and the energy is obtained by breaking down the ATP molecules.
3. Due to this bending of the head, ADP+Pi are also released and as they are released, instantly new ATP joins with the head.
4. Due to the joining of the head with ATP, it separates from the action. Again ATP is broken down Myosin head now joins again at the new active site and this process is repeated.
5. Due to the repeated acts of the head of the transverse bridge, active filament slides and leads to contraction. In the contraction many filaments. Cross bridges participate. The contraction in muscle tissue continues till Ca⁺⁺ remains attached with troponin.

Relaxation

1. When contraction through nerve impulse is stopped in muscle then Ca⁺⁺ is sent back to muscle sarcoplasmic reticulum, which results in troponin – C free from Ca⁺⁺ and active sites of actin filaments are blocked.
2. Now there is no joining or bonding of actin and myosin filament. Filaments come into their original positions and muscles relax.

Q.16. What are the joints? List out the different types of joints.

Sol. A joint is a connection between bones in the skeletal system. It helps by providing the means for movement. Joint can simply be defined as the point or the location within the body where two or more bones meet together.

Types of Joints.

Joints can be classified based on structure and function.

Synarthrosis Joints or Fixed joints

The articulating bones are held together by a dense bundle of tough and white fibrous connective tissue, which cannot be stretched or extended. No movements are possible and hence called as fixed or synarthrosis joints. Joints between the bones of the skull also called the sutures is an example of synarthrosis joints.

Amphiarthrosis Joints or partially movable joints

It is a tough joint in which bones are joined by a disc of white fibrous cartilage which can be stretched a little. Limited movement is possible. The pubic symphysis is an example of an amphiarthrosis joint.

There are two types of amphiarthrosis joints:

1. Pivot Joint.
2. Gliding Joint.

Synovial or movable joints.

The bones joined by synovial joints can move in one or more directions freely, A highly smooth thin layer of hyaline cartilage is found on the surface of the bone where the joint occurs. This joint functions by secreting mucin containing synovial fluid. This fluid provides nutrition to hyaline cartilage and lubrication to joints.

There are three types of synovial or movable joints.

1. Ball and socket joints.
2. Hinge joints.
3. Ellipsoidal joints.

Q.17. Brief out the structure of a skeletal muscle.

Sol. Structure of skeletal muscles:

1. Each skeletal muscle is spindle-shaped and has two different distinct ends viz., origin and insertion. The origin and insertion remain attached to the bones with the help of tendon or aponeuroses.
2. The skeletal muscles of the tongue and upper part of the oesophagus are not attached to the skeleton. These muscles are also called the fatigued muscles or phasic muscles or striated muscles or somatic muscles.
3. The structural unit is called muscle fibre.
4. The muscle fibre is multinucleated or syncytial and bounded by sarcolemma. The muscle fibres are found in groups and each group is called fasciculus. The fasciculus is bounded by endomysium.
5. The fasciculi are also found in the group and each group of fasciculi is bounded by perimysium which is made up of connective tissues.
6. The whole skeletal muscle is bounded by an epimysium.

Q.18. Write the difference between endoskeleton and exoskeleton.

Sol. Endoskeleton and Exoskeleton are the parts of the body of living organisms which possess a body with a complicated network of various organs.

Difference between endoskeleton and exoskeleton.

Q.19.What happens if :

1. The nerve connecting to the skeletal muscles is cut or damaged
2. All joints of an arm become non-movable.

Sol.

1. If the nerve connecting to the skeletal muscles is cut or damaged, then there will be no contraction as signals can not be transmitted from the respective nerve to the skeletal muscles.
2. If all joints of an arm become non-movable, then the limb movement and locomotion will become impossible and a person cannot stretch or use the hand properly.

Q.20. What are the bones? What is the composition of bones?

Sol. The bones are mainly composed of minerals including calcium phosphate, calcium carbonate, and magnesium phosphate.

Bones are the specialized forms of connective tissues, which are composed of cells embedded within an extracellular matrix. They are a rigid connective tissue that forms the skeleton of vertebrates. Bones are the type of tissues, comprising the blood vessels and different types of cells. Overall a newborn baby will have around 300 bones and is reduced to 206.

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