Science Que-Ans (Each of 3 Mark )

1. It is a protective tissue of the plant body.
2. It protects the plant against mechanical injury.
3. It allows exchange of gases through the stomata.

1. Tendons is a dense connective tissue which connects a bone with a muscle.
2. Ligaments are elastic structures which connect bones to bones. 
3. Cartilage is tough, flexible connective tissue found in all vertebrates. Its solid matrix is composed of proteins and sugars. The cells of cartilage are called chondrocytes. They don’t have blood vessels.
4. Cartilage is present in the tip of nose, outer ear joints, between adjacent bones of the vertebral column, limbs and hands in adults.

• The cells of the body surface (i.e., epidermis) from the outer layer of skin. These cells protect the underlying cells from drying, injury and chemical effects. They also protect the body from viral or bacteria infection.
• Epithelial tissues help in absorption of water and nutrients.
• Epithelial tissues help in elimination of waste products.
• Some epithelial tissues perform secretary function. They secrete a variety of substances such as sweat, saliva, (mucus), enzymes, etc.

• Osteoblast: It provides shape to the body.

• Chondroblast: It provided support and flexibility to the body parts.

• Goblet cells: It is a mucus secreting epithelial cell which secrets mucus.

• Neuron: The dendrites receive impulses and the axon takes impulses away from the cell body.

• Muscle cell: They undergo rapid contraction for locomotion.

1. Smooth Muscle: These muscle cells do not have striations or stripes. Hence they are called smooth muscle cells. They are also called involuntary muscles. The cells have a single nucleus and the cells are spindle-shaped.

2. Skeletal Muscle: The skeletal muscles have stripes or striations. Hence they are also called the striated muscles. These skeletal muscles are the most common and widely distributed muscle tissue in the body.

3. Cardiac Muscle: This is a muscle that is found only in the heart. The rhythmic contractions of this muscle help in the pumping of blood through the blood vessels to various parts of the body. The brain controls this muscle and is an involuntary muscle. The cells of this muscle tissue are branched and cylindrical with a single nucleus and striations present.

1. Parenchyma Functions:

1. The main function of parenchyma is to store and assimilate food.
2. Transport of materials occurs through cells or cell walls of parenchyma cells.

2. Collenchyma Functions:

1. It provides mechanical support and elasticity.
2. It provides tensile strength to the plants.

3. Sclerenchyma Functions:

1. It is mainly mechanical and protective in function.
2. It gives strength, rigidity, flexibility and elasticity to the plant body.

• Squamous Epithelium: These are thin, flat cells that are closely packed. The squamous epithelial cells line the cavities of the mouth, oesophagus, alveoli, and blood vessels. This tissue gives protection against mechanical injury and also blocks the entry of germs. If the squamous epithelium is arranged in many layers, it is a compound squamous tissue called the stratified squamous epithelium. We find these kinds of tissues in the skin and also the lining of the oesophagus.

• Cuboidal Epithelium: These cells are cuboidal in shape. They are found in the salivary glands, kidney tubules, sweat glands etc. Their main function includes absorption, secretion, and excretion. If the cuboidal epithelium is arranged in many layers it forms the stratified cuboidal epithelium. It is found on the inner side of the pancreatic ducts and salivary glands. They mainly help in protection.

• Columnar Epithelium: The columnar epithelium has cells that are pillar-like and column-like. We can find them in the lining of the stomach and intestine. Its functions include absorption and secretion.

• Ciliated Epithelium: When the columnar epithelial tissues have cilia, then they are ciliated epithelium. They are present in the lining of the trachea, kidney tubules etc. The rhythmic movement of the cilia helps in the movement of material in one direction.

• Glandular Epithelium: These are modified columnar epithelial tissues. They are large cells that present in the tear glands, sweat glands etc. Their main function is secretion.

1. Bone: It forms athr framework that supports the body. It also anchors the muscles and supports the main organs of the body.

2. Cartilage: Cartilage smoothens bone surfaces at joints.

3. Tendon: Tendons connect bone to muscles with great strength but limited flexibility.

4. Ligaments: Ligaments connect bone to bone and are very elastic.

1. Sieve tubes.
2. Companion cells.
3. Phloem parenchyma.
4. Phloem fibres.

Functions are:

1. Sieve tubes: It conduct food materials prepared in the leaves and greener young stems to all parts of plants.

2. Companion cells: It helps sieve tubes in conduction of food materials.

3. Pholem parenchyma: It helps to store food.

4. Pholem fibres: It provide mechanical strength to plants.

1. Bone is a solid, rigid and stong connective tissue. Its matrix is hard. The matrix is made up of organic as well as inorganic (e.g.calcium and phosphorus) components. Calcium and phosphorus make the bone matrix hard. When a bone is dipped in HCI, bone become soft and pliable as its inorganic components get dissolved in the acid. Only organic matter is left.
2. When a bone is dried, its organic matter get destroyed. Only mineral matter is left.

1. Tendons: Tendons, located at each end of a muscle, attach muscle to bone. Tendons are found throughout the body, from the head and neck all the way down to the feet. The Achilles tendon is the largest tendon in the body.

2. Areolar tissue: Areolar tissue is found b/w the skin and muscles around blood vessels and nerves and in the bone narrow.

3. Cuboidal epithelia: Cuboidal epithelia are found on the surface of ovaries, the lining of nephrons, the walls of the renal tubules, and parts of the eye and thyroid. On these surfaces, the cells perform secretion and absorption.

1. Striated Muscles: It occur in the muscles of limbs, body wall, face, neck, etc. Striated muscles present in tongue, pharynx, diaphragm and upper part of oesophagus are called visceral straited muscles.

2. Smooth Muscles: Smooth muscles are found in the walls of the hollow (tubular) visceral organs except that of the heart. They occur in the wall of alimentary canal and internal organs, ducts of glands, urogenital ducts and blood vessels.

3. Cardiac Muscles: The cardiac muscles occur in the heart.

1. Collenchyma.
2. Sclerenchyma.
3. Parenchyma.

1. Ligament is a form of connective tissue which holds two bones together at joints. When ligament get overstreached, it causes sprain.
2. Heparin is an anticoagulant present in blood that prevent it from clotting. If heparin is absent in blood, blood will be coagulated inside the blood vessels.
3. Striated muscle contraction causes fatigue due to accumulation of lactic acid.

• Neuron: Nervous Tissue..

• Dendrite: Nervous Tissue.

• Cilia: Ciliated Epithelium.

• Collagen fibres: Connective Tissue.

• Elastin fibre: Connective Tissue.

• On the basis of movement: Plants are stationary and they do not move while animals move from one place to another for various reasons. Therefore, the tissues required by plants are those which provide mechanical strength and mostly they are dead in nature whereas in animals the tissues are living as they need to move.
• On the basis of the pattern of growth: The growth pattern of plants and animals also differs. Plants have certain regions which continue to divide throughout the life while the same thing does not happen in case of some other regions. There is more uniform cell growth in animals as compared to plants.

So, tissues are classified considering the pattern of growth.

• On the basis of the structural organization: The structural organization of animals is far more complex as compared to plants. Therefore, there are differences in tissues which are responsible for the structural organization and form a basis of classification.

• Plasma is the main component of blood and consists mostly of water, with proteins, ions, nutrients, and wastes mixed in.
• Red blood cells are responsible for carrying oxygen and carbon dioxide.
• Platelets are responsible for blood clotting.
• White blood cells are part of the immune system and function in immune response.

1. It is simple and living parenchyma tissue.
2.  

1. Cytoplasm.
2. Nucleus.
3. Vacuole.
4. Intercellular space.
5. Cell wall.

3. The main function of parenchyma is the storage of food.

1. The figure represents the location of meristematic tissue in plant body.
2.  

1. Apical meristem.
2. Intercalary meristem.
3. Lateral meristem.

3. Apical meristem increases the length of the stem and root.

Lateral meristem is responsible for growth in grith of stem and root.

1. Squamous epithelium.
2.  

1. Cytoplasm.
2. Nucleus.
3. Cement substance.
4. Basement membrane.

3. Squamous epithelium protects the underlying body parts such as skin, nose, etc. from germs, harmful chemicals and injury.

1. It is neuron, structural and functional unit of nervous system.
2.  

1. Dendrite.
2. Cyton or cell body.
3. Axon.

3. It is located in brain and spinal cord.

1. Tendon.
2. Muscle.
3. Ligament.
4. Bone.

1. It acts as an insulator.
2. Provides support and protection to the vital organs.
3. It acts as a storage of fat.

• Areolar Connective Tissue.
• Adipose Tissue or Body Fat.
• Reticular Connective Tissue.
• Dense Regular Connective Tissue.
• Dense Irregular Tissue.
• Elastic Connective Tissue.
• Cartilage.
• Elastic Cartilage.
• Hyaline Cartilage.
• Fibrocartilage.
• Blood.

• They forms a barrier between the body and the exterior environment.
• These cells provide protection for underlying tissues.
• Simple squamous epithelial cells (glomerulus) in nephrons of kidneys enable rapid filtration of blood and diffusion of small molecules.
• Squamous epithelial cells of lungs (alveoli of lungs) helps to reduce friction and controls vessel permeability.
• It also helps in absorption and filtration.

1. Meristematic tissues: It is of three types: Apical, Lateral and Intercalary.

2. Permanent Tissue: It of two types: Simple and Complex tissues.

Simple tissues are of three types: Parenchyma, Collenchyma and Sclerenchyma.

Complex tissues are of two types: Xylem and Phloem.