Question 1

Question 3State the major functions of the following-Plasma membraneRibosomeLysosomeMitochondriaGolgi apparatusCytoplasmAsters of centrosomeChromosomesGlycogen granuleVacuoles

Accepted Answer

The major functions are as follows-Plasma membrane —Separates contents of cell from its surroundings.Regulates the entry of certain solutes and ions.Maintains shape of the cell in animal cells.Ribosome —Protein synthesisLysosome —Intracellular digestion.Destroy foreign substances.They are referred to as 'suicidal bags' as they destroy cell organelles when they turn old or are damaged.Digest cartilages during formation of bones.Mitochondria —Controls the cell functions.Referred to as ‘power house of the cell’, as energy is stored in the form of ATP.Involved in cellular respiration to release energy.Bearers of genes.Golgi apparatus(in animal cells) —Synthesis and secretion of enzymes, hormones,etc.Acrosomes of sperms are formed.Cytoplasm —Contains organelles perform multitude of functions.Performs all metabolic activities.Asters of centrosome —Cell division – regulation and initiation.Spindle fibre formation.Chromosomes —Passes genetic characteristics from parents to offspring.Glycogen granule —Food for cells.Vacuoles —Stores food, water, pigments and waste products.Renders turgidity to the plant cell.

Question 2

Question 4Mention the three differences between a living cell and a brick in a wall

Accepted Answer

Following are the differences between a living cell and a brick in a wall-Living cellBrickThe living structure is non-rigidLiving structure is rigidContains cellulose chieflyContains soil primarilyIs functional in nature, performs critical functions pertaining to life processesNon-functionalGenerously permeableImpermeable

Question 3

Question 5List any six features found both in plant and animal cells.

Accepted Answer

Given below are the following six features found both in plant and animal cellsCell membrane is present.Golgi body is present.Liquid matrix known as cytoplasm is observed in the cell.Mitochondria generates energy, is found in the cells.Ribosomes are found. They are responsible for protein synthesis.A prominent nucleus is observed.

Question 4

Question 1(xi)The invention of the microscope was a great boon for people to study smaller objects or micro-organisms. Scientists made different microscopes by using different types of lenses for magnification.Gaurav made a table of two scientists and the kind of microscope they invented.The kind of microscopeScientistPRobert HookeQAntony Van LeeuwenhoekIdentify P and QP — Simple microscope, Q — Compound microscope.P — Electron microscope, Q — Simple microscope.P — Compound microscope, Q — Electron microscope.P — Compound microscope, Q — Simple microscope.

Accepted Answer

P — Compound microscope, Q — Simple microscope.Reason — Compound microscope was invented by Robert Hooke and simple microscope was invented by Antony Van Leeuwenhoek.

Question 5

Question 2Differentiate betweenAn organ and an organelleA plant cell and an animal cell pertaining to the presence of plastids.

Accepted Answer

Difference between an organ and an organelle:An organAn organelleIt is bigger in size and visible to naked eyes.It is microscopicCarries out specialized functions in the body.Carries out specialized functions in the cell.Example: Heart, LungsExample: Mitochondria, Ribosomes.A plant cell has plastids while an animal cell does not have plastids.

Question 6

Question 5Mention if the following statements are true or false. If false, suggest the change in the information underlined.Prokaryotic cells have larger ribosomes.Eukaryotic cells have mitochondria.Amoeba is an example of Prokaryotes.Nuclear membrane is present in bacteria.

Accepted Answer

FalseCorrected Statement— Prokaryotic cells have smaller ribosomes.TrueFalseCorrected Statement— Amoeba is an example of Eukaryotes.FalseCorrected Statement— Nuclear membrane is absent in bacteria.

Question 7

Question 3How do you say that a cell also has a life span and death like an organism? Give one example.

Accepted Answer

The cells behave like an organism. They carry out all the processes like an organism viz. respiration and elimination of wastes. They also have a life span like an organism. They grow, age, deteriorate and finally die. The dying cells are dissolved or destroyed by their own lysosomes. For example, Red blood cells of our body die after 120 days. These cells are continuously replaced by new cells in our body

Question 8

Question 6What is the difference between an organ and an organelle?

Accepted Answer

AttributesOrganOrganelleSizeVisible to the naked eyes, larger in sizeMicroscopicLocationThey are present throughout the bodyKnown as little organs, are found within the cell.FunctionCarry out functions of the entire bodyCarry out functions within the cellExampleHeart, Lungs, LiverRibosomes, Endoplasmic reticulum, Golgi complex.

Question 9

Question 7Do you think the cells of an elephant would be larger than the cells of a rat? Explain briefly.

Accepted Answer

Cell is the basic unit of life. Cells aggregates to form tissue, organ, organ system and ultimately organism. Elephant has more cells compared to rat. The cell size is independent of the size of the entity. The cell size of a rat and that of an elephant are the same. Within the entity, the cell size is the same, it does not differ. However, what varies is the number of cells. Number of cells in a large entity such as elephant is much more compared to a smaller entity such as a rat.

Question 10

Question 1Given below is the structure of nucleus of a cell. Read the information below the diagram and fill in the blanks:Nucleus is the most important part of the cell. It is located in the central area in animal cells but pushed towards the periphery in plant cells due to the presence of a large vacuole in the centre. It regulates and coordinates various life processes of the cell and also plays an important role in cell division.Nucleus has a delicate, protective surrounding layer (a) ............... which is filled with a relatively dense fluid (b) ............... . There are certain thread-like structures suspended in the fluid called (c) ............... . These thin thread-like fine structures become thick and ribbon-like during the time of cell division. These prominent ribbon-like structures are called (d) ............... .Nucleus contains a spherical, dense body inside it, called as (e) ............... which participates in protein synthesis.

Accepted Answer

Nucleus has a delicate, protective surrounding layer (a) Nuclear membrane which is filled with a relatively dense fluid (b) Nucleoplasm. There are certain thread-like structures suspended in the fluid called (c) Chromatin. These thin thread-like fine structures become thick and ribbon-like during the time of cell division. These prominent ribbon-like structures are called (d) Chromosomes. Nucleus contains a spherical, dense body inside it, called as (e) Nucleolus which participates in protein synthesis.

Question 11

Question 4State whether the following statements are true (T) or false (F):(a) All animal cells contain a cell wall.(b) The cell wall is made of protein.(c) Centrosome occurs in animal cells.(d) Plant cells contain large vacuoles.(e) Protoplasm is the part of the cell which surrounds the nucleus.(f) Genes are located in chromosomes.(g) Anthocyanin are the pigments of flowers, which are dissolved in cell-sap.

Accepted Answer

(a) FalseCorrected statement — All plant cells contain a cell wall.(b) FalseCorrected statement — The cell wall is made of cellulose.(c) True(d) True(e) FalseCorrected statement — Cytoplasm is the part of the cell which surrounds the nucleus.(f) True(g) FalseCorrected statement — Anthocyanin are the pigments of fruits, which are dissolved in cell-sap.

Cell: The Unit of Life

Descriptive Answer Type

Multiple Choice Type

Progress Check 3

Progress Check 4

Short Answer Type

Very Short Answer Type