Q1. The exoskeleton is absent in
The endoskeleton consists of hard parts present inside the body. The exoskeleton consists of hard parts present on the surface of the body. Amphibians do not show the presence of an exoskeleton. So, the exoskeleton is absent in frog.
Q2. Which of the following facial bones is unpaired?
Facial bones include 2 nasals, 2 maxillae, 2 palatines, 2 zygomatic or cheek bones, 2 lacrimals, 2 inferior nasal conchae, 1 vomer and 1 mandible. The vomer is one of the unpaired facial bones of the skull. It forms the posterior part of the nasal septum, with the anterior part formed by the ethmoid bone.
Q3. The axis vertebra is identified by
- Sigmoid notch
- Deltoid ridge
- Odontoid process
The axis is the second cervical vertebra of the spine. The unique characteristic of this bone is a strong odontoid process known as dens. It rises perpendicularly from the upper surface of the body.
Q4. The contractile unit of muscle is a part of myofibril between
- Z line and I band
- Z line and Z line
- Z line and A band
- A band and I band
The region between two successive Z lines in a myofibril is a contractile unit called a sarcomere.
Q5. Which of the following is a contractile protein of a muscle?
Actin and tropomyosin are part of thin filaments of skeletal muscle. Tubulin is present in microtubules. Myosin is a contractile protein of muscles.
Q6. Which of the following gives the correct total number?
- Types of diabetes – 4
- Cervical vertebrae in humans – 8
- Floating ribs in humans – 4
- Amino acids found in proteins – 16
There are 3 main types of diabetes – Type I diabetes, type II diabetes and gestational diabetes.
7 cervical vertebrae are present in humans.
The 11th and 12th pairs of ribs (total 4 ribs) are called floating ribs.
A total of 20 amino acids are found in proteins.
Q7. The only immediate source of energy for muscular contraction is
ATP is the only immediate source of energy for muscular contraction. ATP is replenished within muscle fibres from creatine phosphate (anaerobic respiration), by glycolysis (anaerobic respiration) and by cellular respiration (aerobic respiration).
Q8. The number of vertebrae present in the cervical, thoracic, lumbar, sacral and coccyx regions, respectively, are
- 12, 7, 5, 1, 1
- 1, 7, 5, 12, 1
- 7, 5, 1, 12, 1
- 7, 12, 5, 1, 1
- 5, 12, 7, 1, 1
The vertebrae are grouped into five categories:
Cervical vertebrae: 7, present in the neck
Thoracic vertebrae: 12, present in the upper back
Lumbar vertebrae: 5, located in the abdomen
Sacral vertebrae: 5, present in the pelvis
Coccygeal vertebrae: 4, present in the vestigial tail
Q9. A sheet or broad band of fibrous connective tissues which is deep in the skin and surrounds muscles and other organs of the body are
The fascia is a layer of fibrous connective tissue which surrounds muscles, groups of muscles, blood vessels, and nerves. It binds some structures together and permits others to slide smoothly over each other.
Q10. The largest muscle in the human body is
The largest muscle in the human body is gluteus maximus, which is also known as the buttock muscle. It is large because its main function is to keep the body upright.
Q11. A sesamoid bone is
The patella or kneecap is a sesamoid bone. A sesamoid bone is a bone which develops in a muscle tendon rather than being attached by ligaments to another bone.
Q12. Collagen is a
- Derived protein
Scleroproteins are a class of generally insoluble proteins such as collagen found in the skeletal and connective tissues.
Q13. The elbow joint is an example of
- Ball and socket joint
- Pivot joint
- Hinge joint
- Gliding joint
The hinge joint allows movements in one plane only. The knee joint, elbow joint, ankle joint and the joints between the phalanges are all examples of a hinge joint.
Q14. The pectoral girdle is constituted by
- Scapula and clavicle
- Radius and ulna
- Ilium and ischium
- Maxilla and mandible
The pectoral girdle consists of the scapula (or the shoulder blade) and the clavicle (or the collar bone).
Q15. Which one of the following is anatomically correct for the human body?
- Collar bones: 3 pairs
- Salivary glands: 1 pair
- Cranial nerves: 10 pairs
- Floating ribs: 2 pairs
Floating ribs: 2 pairs
Collar bones/clavicles: 1 pair
Salivary glands: 3 pairs
Cranial nerves: 12 pairs
Q16. Which one of the following is the correct pairing of a body part and the kind of muscle tissue which moves it?
- Iris – Involuntary smooth muscle
- Heart wall – Involuntary unstriated muscle
- Biceps of upper arm – Smooth muscle fibres
- Abdominal wall – Skeletal muscle
Iris – Involuntary smooth muscles
Heart wall – Cardiac muscles
Biceps of upper arm – Striated muscle fibres
Abdominal wall – Smooth muscles
Q17. ATPase enzyme needed for muscle contraction is located in
During muscle contraction, hydrolysis of ATP into ADP and inorganic phosphate occurs. The energy released during the process raises the meromyosin head to a high-energy state. The enzyme myosin ATPase catalyses the reaction in the presence of Ca2+ and Mg2+.
Error! Filename not specified.
Q18. Which category of muscle does not get tetanised?
- Striated unbranched muscles
- Cardiac muscles
- Non-striated unbranched muscles
- Non-striated branched muscles
Cardiac action potentials have a long duration of up to 300 ms (nerve and skeletal muscles have a duration of 1-3 ms). The long refractory period (the time taken to reach −65 mv) means cardiac muscles cannot be tetanised.
Q19. The number of bones in the human skull is
The skull includes bones of the cranium (8), ear bones (3 in each ear = 6), facial bones (14) and hyoid bone (1). So, there are a total of 29 bones in the human skull.
Q20. The H zone in the skeletal muscle fibre is due to the
- Central gap between myosin filaments in the A band.
- Central gap between actin filaments extending through myosin filaments in the A band.
- Extension of myosin filaments in the central portion of the A band.
- Absence of myofibrils in the central portion of the A band.
The dark A band in the skeletal muscle fibre has a middle light zone called the H zone. It occurs due to the central gap between actin filaments extending through myosin filaments in the A band.