Chapter 7: Structural Organisation in Animals

Q1Written answer

Give the location of hepatic caeca in a cockroach. What is their function?

Solution;

The hepatic caeca which are also known as gastric caeca is a 6-8 narrow and hollow ring-like blind tubules which are present in the junction of the foregut and midgut. They help in the digestion of food in cockroaches.

2. Frogs are beneficial for mankind, justify the statement.

Show solutionHide solution

Worked solution

They are an important part of the food chain. They help farmers by eating insects and pest and protect from insect infection. They are also used as a food source for humans in some regions of the world. For experiments and researches, they have been used.

Q2Written answer

Frogs are beneficial for mankind, justify the statement.

Show solutionHide solution

Worked solution

They are an important part of the food chain. They help farmers by eating insects and pest and protect from insect infection. They are also used as a food source for humans in some regions of the world. For experiments and researches, they have been used.

Q3Written answer

The body of sponges does not possess tissue level of organisation though it is made of thousands of cells. Comment.

Show solutionHide solution

Worked solution

Most of the multicellular organisms possess specialized or advanced tissue level but sponges have a cellular tissue level. They do not form tissues and their bodies perforated which allows water to pass through them easily.

Q4Written answer

Structural organisation in animals attains different levels as cell – organ – organ system. What is missing in this chain? Mention the significance of such an organisation.

Show solutionHide solution

Worked solution

the issue is missing in the given chain. It should be cell – tissue — organ – organ system. A tissue is a collection of similar types of cells which together forms an organ and these organs form an organ system.

Q5Written answer

Stratified epithelial cells have a limited role in secretion. Justify their role in our skin.

Show solutionHide solution

Worked solution

Stratified epithelial cells help in the protection of the dry skin. It has multi-layers and thus does not have much role in secretion.

Q6Written answer

How does a gap junction facilitate intercellular communication?

Show solutionHide solution

Worked solution

It occurs by the communication between two cells bypassing of small signalling molecules from one cytoplasm to adjacent cytoplasm.

Q7Written answer

Why are blood, bone and cartilage called connective tissue?

Show solutionHide solution

Worked solution

They have a role in the binding and connection of different tissues and organs. They help in providing structural rigidity, support and protection of the body. They help in the transport and exchange of various enzymes, hormones, gases and molecules such as nitrogenous wastes, vitamins, etc.

Q8Written answer

Why are neurons called excitable cells? Mention special features of the membrane of the neuron?

Show solutionHide solution

Worked solution

Neurons are called excitable cells because they have an electrical potential difference

1. During the resting stage of the neuron, it has a sodium-potassium ion pump (i.e., Na+- K+ ion pump).

2. A change in the potential difference spread changes in the entire neuron

3. Stimulus in normally obtained in a place known as trigger zone in which sodium ions (i.e., Na+ ions) are abundantly present.

Q9Written answer

Why earthworm is called the friend of a farmer?

Show solutionHide solution

Worked solution

The earthworm is called a friend of farmers because they help farmers by moving through the soil which helps in aeration of the soil. The excreta which is released by them helps in increasing the fertility of the soil.

Q10Written answer

How do you distinguish between dorsal and ventral surface of the body of earthworm?

Show solutionHide solution

Worked solution

The dorsal surface of the body of earthworm has a dark dorsal median line than the ventral surface of the body of earthworm.

My Cart

Your Cart 0

SHORT ANSWER TYPE QUESTIONS