Question 1

Give reasons why mitochondria is called powerhouse of the cell?

Accepted Answer

Mitochondria are cell organelles present in the eukaryotic cells. They are involved in the cellular respiration. They releases energy from food. They generate energy rich molecules, ATP from cellular respiration which is later used for other process. Hence, mitochondria are called as the powerhouses of the cell.

Question 2

Difference between Prokaryotic cell and Eukaryotic cell.

Accepted Answer

Prokaryotic cell Eukaryotic cellThey lack a well-defined nucleus, have a nucleoid instead.Have&#10;a well-defined nucleus enclosed in the nuclear membrane.Usually&#10;have double-stranded, circular DNA.Have&#10;a linear double-stranded nucleus.Do&#10;not have mitochondria. Mitochondria&#10;are present.Have&#10;70S ribosomes.Have&#10;80S ribosomes.Golgi&#10;apparatus and endoplasmic reticulum also absent.They&#10;do have Golgi apparatus and endoplasmic reticulum.

Question 3

Draw a well labelled diagram of nucleus.

Accepted Answer

The nucleus is considered as the director or controller of the cell. The nucleus is a double membrane-bound organelle. The nuclear envelope consists of two membranes, an outer membrane, and an inner membrane.The nuclear membrane is perforated by apertures known as nuclear pores.Nuclear membranes surround the cytoplasm of nucleus known as nucleoplasm. DNA is present in nucleoplasm in the form of chromatin. When the cell prepares to divide, the chromatin condenses and thickens into chromosomes.Within the nucleus is present a spherical body known as nucleolus which is closely associated with nucleolar organizer region of two or more chromosomes of the set.

Question 4

Which cell organelle is present in both prokaryotic and eukaryotic cells?

Accepted Answer

Prokaryotes and eukaryotes are the two different types of cells. Eukaryotic cells contain membrane-bound organelles, such as the nucleus, endoplasmic reticulum, mitochondria while prokaryotic cells do not but the ribosome is the only organelle that can be seen in both prokaryotic and eukaryotic cells. Prokaryotic and eukaryotic ribosomes perform the same functions that is protein synthesis, however, eukaryotic ribosomes are much larger than prokaryotic ones.Thus, the correct answer is option D.

Question 5

Give reasons why lysosomes are called suicidal bag of the cells.

Accepted Answer

Lysosomes are called suicidal bags of cells. They contain hydrolytic enzymes. If the cell is damaged, the lysosomes undergo autolysis and burst open. This results in the release of those hydrolytic enzymes. The released enzymes then digest their own cell and ultimately the cell dies. Hence, they are called suicidal bags of the cells.

Question 6

Name the types of chromosomes based on the position of centromere and draw suitable diagram for each.

Accepted Answer

The type of chromosomes based on the position of centromere are of the following four types : 1) Metacentric chromosome: centromere in middle forming two equal arms.2) Sub-metacentric chromosome: centromere placed near to one end resulting in one shorter and one long arm.3) Acrocentric chromosome: Centromere placed close to one end forming one extreme short and one extreme long arm.4) Telocentric chromosome: terminally placed centromere.

Question 7

State the major functions of the following:(a) Plasma membrane      (b) Ribosome(c) Lysosome                    (d) Mitochondria(e) Golgi apparatus           (f) Cytoplasm(g) Asters of centrosome   (h) Chromosomes(i) Glycogen granule         (j) Vacuoles

Accepted Answer

The functions of the given are :(a) Plasma membrane It separates the content of the cell from its surroundings.It regulates the entry of certain solids and ions into the cell.It maintains the shape of the cell that is the animal cell.(b) RibosomeIts main function is Protein synthesis.(c) Lysosome     Intracellular digestion and Destroy foreign substances.When a cell is old or injured this rapidly destroy organelles hence called suicide bags.(e) Golgi apparatusSynthesis and secretion of enzymes, hormones and etc.The formation of acrosome of sperm.(d) MitochondriaRelease of energy form pyruvic acid produced in the cytoplasm in the form of ATP and helps in the Synthesis of respiratory enzymes.(f) CytoplasmDifferent organelle is contained in it perform different functions.All metabolic activities occur in it.Medium of earlier steps of respiration(g) Asters of centrosomePresent in an animal cell and helps during the process of mitosis. (h) ChromosomesChromosomes carry hereditary information or genes.(i) Glycogen granuleStarch glycogen and fat containing granules serve as food for the cell.(j) VacuolesStorage of water and other substances, food pigments and waste products.Give turgidity to the plant cell by pressing against a cell wall.

Question 8

Which of the following is not a characteristic of living things?

Accepted Answer

All the given characteristics are peculiar and prominent for the living things.Living things cannot change their external environment, as because the external environment depends upon the several biogeographical factors. Living things adjust themselves according to external environment, as they have immense potential of homeostasis, which helps them to acclimatize according to the changing environment.  Skin and the hormonal response helps to sense the changing condition which is further analyzed by the brain in parietal lobe.

Question 9

Which of the following options are not a function of ribosomes?(i) It helps in manufacture of protein molecules.(ii) It helps in manufacture of enzymes.(iii) It helps in manufacture of hormones.(iv) It helps in manufacture of starch molecules.

Accepted Answer

Ribosomes are majorly involved in protein synthesis, as these are the sites of protein synthesis and enzymes. It also synthesizes amino acids which polymerize to form proteins.

Question 10

Which of the following is not a function of vacuole?

Accepted Answer

Vacuoles are storage bubbles found mostly in plant cells. These are used for storage of food or water. The vacuolar membrane is a single layered and is called as tonoplast. Osmotic pressure and turgidity is maintained by vacuoles. They store toxic metabolic by-products or end products of plant cells. Such vacuoles are thrown out of the cell by exocytosis. Thus, the correct answer is option D.