Q: Distinguish between red muscle fibres and white muscle fibres.

RED MUSCLE FIBERS(Tonic) WHITE MUSCLE FIBERS(Twitch) 1. These are thin and smaller in size. 1. These are thick and larger in size. 2. They are red in colour as they contain a large amount of myoglobin. 2. They are white in colour as they contain a small amount of myoglobin. 3. They contain numerous mitochondria. 3. They contain less number of mitochondria. 4. They carry out slow and sustained contractions for a long period. 4. They carry out fast work for a short duration. 5. Sarcoplasmic reticulum is moderately developed. 5. Sarcoplasmic reticulum is well developed. 6. The fibres are supplied with abundant blood capillaries. 6. They are moderately vascularised. 7. Lactic acid does not accumulate. 7. Lactic acid accumulates. 8. They perform aerobic respiration. 8. During strenuous exercise, it switches over to anaerobic respiration.

Question 1

Diagrammatically show the difference between the three types of muscle fibres.

Accepted Answer

Three types of muscle fibres are smooth muscle (non-striated), cardiac muscles and skeletal muscles (striated muscles).

Question 2

Earthworms are known as farmers' friends. Why?

Accepted Answer

Earthworms are farmers' friends because they improve the quality of the soil like water holding capacity, moisture, and nutrient content by burrowing into the soil. The soil becomes loose and porous. Also, the worm castings improve the distribution of organic matter in the soil.

Question 3

Study the diagram given below and then answer the questions that follow:(a) Identify the tissue and give a reason to support your answer.(b) Name the parts labelled 1,2,3 and 4.(c) Where is this tissue likely to be found in the plant?(d) State the function of the parts labelled 1,2,3 and 4.

Accepted Answer

(a) The diagram given is a section of a phloem tissue in plants. (b) The following parts are labelled: 1 &#8211; Sieve cell 2 &#8211; Phloem parenchyma cell 3 &#8211; companion cell 4 &#8211; sieve plate(c) In plants, phloem is  found in the stem and leaves as it is the tissue that conducts food, the manufactured food in the leaves needs to be transported to other plant parts. (d) Listed below are the functions of the labelled parts:1: Sieve cell &#8211; assists in transporting food from leaves to storage structures and other plant parts.2: Phloem parenchyma cell &#8211; Stores fat, starch and other organic food material3: companion cell &#8211; Facilitates the functioning of the cells of sieve tube4: sieve plate &#8211; Dissolved organic solutes and water moves through these structures as it contains perforations

Question 4

Distinguish between  red muscle fibres and white muscle fibres.

Accepted Answer

&#10; &#10;  &#10;  RED MUSCLE FIBERS(Tonic)&#10;  &#10;  &#10;  WHITE MUSCLE FIBERS(Twitch)&#10;  &#10; &#10; &#10;  &#10;  1. These are thin and smaller in size.&#10;  &#10;  &#10;  1. These are thick and larger in size.&#10;  &#10; &#10; &#10;  &#10;  2. They are red in colour as they contain a large amount of myoglobin.&#10;  &#10;  &#10;  2. They are white in colour as they contain a small amount of myoglobin.&#10;  &#10; &#10; &#10;  &#10;  3. They contain numerous mitochondria.&#10;  &#10;  &#10;  3. They contain less number of mitochondria.&#10;  &#10; &#10; &#10;  &#10;  4. They carry out slow and sustained contractions for a long period.&#10;  &#10;  &#10;  4. They carry out fast work for a short duration.&#10;  &#10; &#10; &#10;  &#10;  5. Sarcoplasmic reticulum is moderately developed.&#10;  &#10;  &#10;  5. Sarcoplasmic reticulum is well developed.&#10;  &#10; &#10; &#10;  &#10;  6. The fibres are supplied with abundant blood capillaries.&#10;  &#10;  &#10;  6. They are moderately vascularised.&#10;  &#10; &#10; &#10;  &#10;  7. Lactic acid does not accumulate.&#10;  &#10;  &#10;  7. Lactic acid accumulates.&#10;  &#10; &#10; &#10;  &#10;  8. They perform aerobic respiration.&#10;  &#10;  &#10;  8. During strenuous exercise, it switches over to anaerobic respiration.&#10;  &#10; &#10;

Question 5

A person met with an accident in which two long bones of hand were dislocated. Which among the following may be the possible reason?

Accepted Answer

The two long bones in hand are the radius and the ulna. Annular ligament or orbicular ligament is a strong band of fibres present on the head of the radius that retains it in contact with the radial notch of the ulna. The person must have broken the ligament which dislocated these long bones leading to fracture. So, the correct answer is option C.

Question 6

Describe the structure and function of different types of epithelial tissues. Draw diagram of each type of epithelial tissue.

Accepted Answer

Epithelial tissues are the covering or protective tissues in the animal body. Epithelium covers most organs and cavities within the body and keep different body systems separate. The skin, the lining of the mouth, the lining of blood vessels, lung alveoli and kidney tubules are all made of epithelial tissue. Epithelial tissue cells are tightly packed and form a continuous sheet. They have only a small amount of cementing material between them and almost no intercellular spaces. The permeability of the cells of various epithelia play an important role in regulating the exchange of materials between the body and the external environment and also between different parts of the body. Regardless of the type, all epithelia are usually separated from the underlying tissue by an extracellular fibrous basement membrane. Epithelial tissues are of following types: (1) Simple squamous epithelium (2) Stratified squamous epithelium (3) Columnar epithelium, and (4) Cubodial epithelium. These tissues differ in structure that correlate with their unique functions. For example, in cells lining blood vessels or lung alveoli, where transportation of substances occurs through a selectively permeable surface, there is a simple flat kind of epithelium. This is called the simple squamous epithelium. Simple squamous epithelial cells are extremely thin and flat and form a delicate lining. The skin. oesophagus and the lining of the mouth are also covered with squamous epithelium. Skin epithelial cells are arranged in many layers to prevent wear and tear. Since. they are arranged in a pattern of layers, the epithelium is called stratified squamous epithelium. Where absorption and secretion occur, as in the inner lining of the intestine. Tall epithelial cells are present. This columnar epithelium facilitates movement across the epithelial barrier. In the respiratory tract. the columnar epithelial tissue also has cilia. which are hair-like projections on the outer surfaces of epithelial cells. These cilia can move, and their movement pushes the mucus forward to clear it. This type of epithelium is thus ciliated columnar epithelium. Cuboidal epithelium forms the lining of kidney tubules and ducts of salivary glands, where it helps in the filtration process. Epithelial cells often acquire additional specialization as gland cells. which can secrete substances at the epithelial surface. Sometimes a portion of the epithelial tissue folds inward, and a multicellular gland is formed. This is glandular epithelium.

Question 7

While doing work and running, you move your organs like hands, legs etc. Which among the following is correct?

Accepted Answer

Smooth muscles are located in the visceral organs of the body. For example, urinary bladder, uterus, respiratory tract, etc. These muscles are not connected to bones and do not function in movements like walking and running. In contrast, skeletal muscles attach directly to the skeleton which synchronizes the movement of muscles with bones. These skeletal muscles are attached to bones with a tough, flexible band of fibrous connective tissue called tendon. When the skeletal muscles contract, it pulls the tendon attached to the bone, aiding to the movement of bones. Thus, the correct answer is option D - 'Skeletal muscles contract and pull the tendon to move the bones.'

Question 8

Give three features of cardiac muscles.

Accepted Answer

Cardiac muscles are found in heart. Characteristics of cardiac muscles are (any three):The muscles have striations just like skeletal muscles by having actin and myosin filaments that are arranged into sarcomeres.The muscles have an involuntary function as their functioning is not under our control.The muscles are myogenic - means the contractions are generated within the muscles.The muscles consist of a network of interconnected muscle fibres each of which has numerous mitochondria, myofibrils with sarcomere and many nuclei.The muscle tissue has no regenerative capacity.

Question 9

Name the following.1) Tissue that forms the inner lining of our month.2) Tissue that connects muscle to bone in humans.3) Tissue that transports food in plants.4) Tissue that stores fat in our body.5) Connective tissue with a fluid matrix.6) Tissue present in the brain.

Accepted Answer

1) Tissue that forms the inner lining of our month.- Squamous epithelial tissue.2) Tissue that connects muscle to bone in humans.- Tendon (fibrous connective tissue)3) Tissue that transports food in plants.- Phloem4) Tissue that stores fat in our body.- Adipose tissue 5) Connective tissue with a fluid matrix.- Blood6) Tissue present in the brain.- Nervous tissue

Question 10

Intestine absorbs the digested food materials. What type of epithelial cells are responsible for absorption?

Accepted Answer

Columnar epithelium is located in the digestive tract in the stomach, large intestine, small intestine and functions as a barrier to bacteria and other microbes but permits the absorption of digested food.Stratified squamous epithelium cells are present in parts of the body where constant abrasion take place, eg., the outer layer of skin, inner lining of the mouth, oesophagus, and vagina. Spindle fibres are protein structures which arise from centrioles in a cell during mitosis (functions in a separation of chromatids during cell division).Cuboidal epithelium is located in kidney tubules, glandular ducts, ovaries, and the thyroid gland(functions in protection, secretion and absorption. Thus, the correct answer is option B.