MODEL PAPER 3 BIOLOGY - MODEL PAPER 3

The specialized centre which can reduce the inspiratory duration upon stimulation is ________.

Which of the following symptoms will be shown in a person suffering from diabetes?

Spirulina is used in medicines, from which type of plants it is derived?

Which hormone is responsible for seed dormancy?

In water, frogs breathe through the skin. What is the name for such kind of respiration?

Name the end products of light reaction of photosynthesis. Mention the fate of each of them.

Write any three advantages of scientific names.

What are secondary sexual characters?

Differentiate between eyes of cockroach and eyes of frog.

Distinguish between
i. Grey matter and White matter
ii. A stimulus and An Impulse

Give the cause for the Heart sounds.

Draw a standard ECG and explain the different segments in it.

Differentiate between a ball and socket joint and a pivot joint.

How are gibberellins useful in agriculture to improve productivity. Give any three points in support of your answer.

Various parts of the plant such as stems leaves, and even fruits are modified into underground parts to perform various functions such as stems, leaves, and even fruits.
The stems in ginger and banana are underground and swollen due to storage of food. They are called rhizome. Rhizome of ginger is a modification of stem because it bears nodes, internodes, terminal buds, scaly leaves and buds, which give rise to aerial shoots. It is not a root because root does not have nodes and internodes. Also, rhizome does not perform the function of roots i.e. anchorage and absorption, rather it serve as reservoir for storage of food. Similarly, corm is an underground stem in Colocasia (jimikand) The tips of the underground stem in potato become swollen due to accumulation of food and forms tuber.



i. Observe the given flow chart and mention what are the four types of Underground stem modification also mention one example of each. (1)
ii. Ginger is an underground stem but why it is distinguished from a root? (1)
iii. Why do the tips of modified stems in potatoes become swollen? (2)

OR

Are all underground parts of a plant roots? (2)

Does a group of smaller cells have a higher metabolic rate than a single large cell of the same volume? Explain.

Describe in brief the structure of the cell of the brain.

Where is the electron transport system operative in mitochondria? Explain the system highlighting the role of oxygen.

In the following flow chart, replace the symbols a,b,c and d with appropriate terms. Briefly explain the process and give any two application of it.

What are homologous chromosomes? What happens to homologous chromosomes during meiosis?

Assertion (A): Special vascularised structures called gills are used by most of the aquatic arthropods and molluscs.
Reason (R): Vascularised bags called lungs are used by the terrestrial forms for the exchange of gases.

Assertion (A): Amylase enzyme stops its activity in stomach.
Reason (R): In stomach, pH is acidic due to presence of HCl.

Assertion (A): Inspiration occurs due to muscular relaxation.
Reason (R): During inspiration, the diaphragm and external intercostal muscle contract simultaneously

Assertion (A): Paroxysms are regular and daily in Quotidian malaria.
Reason (R): Recurrence of fever is after 48 hours, if the infection is caused by Plasmodium malariae.