Cell Cycle and Cell Division — BIOLOGY STD 11 Science — Question

Which features make mammals as the most successful and dominant animals?

Distinguish between Red, Brown and Green Algae.

Describe the role of haemoglobin in the transport of respiratory gases.

Describe in detail the events in Prophase I of meiosis.

Sumit, student of class XI when returned from school was told by his mother that his grandfather was complaining about some uneasiness. Sumit told his mother to take him to the doctor. The doctor tied a cuff around his arm and pumped air, then he slowly released the air. The handcuff was connected to a tube containing mercury. Doctor told Sumit that his grandfather is suffering from high blood pressure and put him on medication. The doctor also advised him to take precautions and rest and asked Sumit's mother to bring him for regular checkups.

1. What is meant by blood pressure?
2. What is the harmful effect of blood pressure on health?
3. Enumerate the range of normal and high blood pressure in human.
4. What values are displayed by Sumit as a good grandson?

Describe the following as asked against each:

1. Gizzard in cockroach: Function
2. Open type of vascular system: One example
3. Heart: Name of tissue.

Explain the guidelines/ principles for nomenclature.

Match the following

	Column I		Column II
a.	Cristae	i.	Flat membranous sacs in stroma.
b.	Cisternae	ii.	Infoldings in mitochondria.
c.	Thylakoids	iii.	Disc-shaped sacs in Golgi apparatus.

Enzymes are proteins. Proteins are long chains of aminoacids linked to each other by peptide bonds. Aminoacids have many functional groups in their structure. These functional groups are, many of them at least, ionisable. As they are weak acids and bases in chemical nature, this ionization is influenced by pH of the solution. For many enzymes, activity is influenced by surrounding pH. This is depicted in the curve below, explain briefly.