Question 1

Question 1Briefly describe the structure of nucleus and mention its any two function.

Accepted Answer

Nucleus is a small spherical mass mostly located towards the centre of the cytoplasm. Nucleus has the following parts:A delicate, porous nuclear membrane which encloses a relatively dense Nucleoplasm.Inside the nucleoplasm the small darker body Nucleolus is present. The nucleoplasm contains chromosomes.Below diagram shows the structure of the Nucleus:The two functions of nucleus are:It regulates and coordinates various life processes of the cell.It plays an important role in cell division.

Question 2

Question 2Name the scientist who coined the term "cell". How many lenses did he use in his microscope? What did he observe under his microscope?

Accepted Answer

Robert Hooke is the scientist who coined the term "cell". He used two lenses in his microscope. Under his microscope, he examined a very thin slice of a dead cork (the bark of the trees) and observed a cluster of box-like cubicles piled up together.

Question 3

Question 4Write the significance of cell division (4 points).

Accepted Answer

Cell division is the necessity for the existence of all living organisms, including plants. This is because new cells need to be produced for-ReplacementRepairReproductionGrowth

Question 4

Question 6The diagram given alongside represents a cell. Study the same and answer the following questions :Is it a plant cell or an animal cell ? Give reason in support of your answer.Label the guidelines 1 to 8.Name one structure shown in the figure which is found in both plant and animal cells, but with different sizes.What is the protective membranous covering of the part shown as 4 called ?Name any two organelles.

Accepted Answer

The given diagram shows an Animal cell. It does not have a cell wall and plastids. Also, the vacuoles are small, unlike the big ones present in a plant cell.The guidelines 1 to 8 indicate:1 → Cell Membrane2 → Centrosome3 → Cytoplasm4 → Nucleus5 → Nucleolus6 → Chromosomes7 → Mitochondria8 → VacuoleVacuoles are present in both plant and animal cells. They are larger in size in plant cells, but smaller in size in animal cells.Part 4 is Nucleus. Its protective membranous covering is called Nuclear membrane.Two organelles are — mitochondria and endoplasmic reticulum.

Question 5

Question 3Briefly describe the three essential parts of the cell.

Accepted Answer

The three essentials parts of the cell are Cell membrane, Cytoplasm and Nucleus.Cell membrane — Each cell is surrounded by a membrane which is called cell membrane. It is a living structure that is very thin, delicate and flexible. It has fine pores in it, through which only certain substances can pass in and out while others cannot. Therefore, the cell membrane is called selectively permeable.Cytoplasm — The cytoplasm is a semi-liquid, colourless, and translucent substance. It is found between the nucleus and the cell membrane.Nucleus — Nucleus is a small spherical maas mostly located towards the centre of the cytoplasm. It is the most important part of the cell. It regulates and coordinate various life processes of the cell. It plays an important role during cell division.

Question 6

Question 5(a)State the difference between Nucleus and Nucleolus.

Accepted Answer

Difference between Nucleus and Nucleolus:NucleusNucleolusNucleus is a small spherical mass mostly located towards the centre of the cytoplasm.Nucleolus is a small darker body, which is present in the nucleoplasm inside the nucleus.Nucleus regulates and coordinates various life processes of the cell.Nucleolus helps in protein synthesis and production of the ribosome in the cells.

Question 7

Question 5(c)State the difference between Cell Wall and Cell Membrane.

Accepted Answer

Difference between Cell Wall and Cell Membrane:Cell WallCell MembraneCell Wall is found in the plant cell.Cell Membrane is found in both the plant cell and animal cell.Cell Wall is a non living structure.Cell Membrane is a living structure.Cell Wall is freely permeable, allowing substances in solution to enter and leave the cell without any hindrance.Cell Membrane is selectively permeable, allowing only certain molecules in solution to enter and leave the cell.

Question 8

Question 6List the major differences between a plant cell and an animal cell?

Accepted Answer

Difference between plant cell and animal cell:Plant CellAnimal CellPlant cell has a definite cell wall.Animal cell has no cell wall.Cytoplasm not so dense. Only a thin layer of cytoplasm.Cytoplasm denser and more granular. It fills almost the entire cell.Plastid are present.Plastid are not present.Vacuoles prominent, fewer in number and concerned with storage of water and nutrients.Vacuoles are small, numerous and concerned with excretion or secretion.

Question 9

Question 7Briefly discuss the importance of the chromosomes in an organism?

Accepted Answer

The Nucleoplasm of the nucleus contains chromosomes. Chromosomes contain units called Genes. These genes are responsible for transmitting characteristics from parents to offsprings. Thus, the chromosomes are extremely important for an organism.

Question 10

Question 8Fill up the blanks with the terms given below in the box:pigments, wall, pre-existing , cell, vacuolesThe ............... is the structural unit of all living thingsAll cells arise from ............... cells.Animal cells have no cell ............... .Plastids contain ............... ................ are filled with water and dissolved substance.

Accepted Answer

The cell is the structural unit of all living things.All cells arise from pre-existing cells.Animals cells have no cell wall.Plastids contain pigment.Vacuoles are filled with water and dissolved substances.

Question 11

Question 9Try to finds the names of four cell organelles hidden in this maze. (Hint: The hidden words can appear horizontally or vertically; forward or backward or even mixed up). Write them in the lines provided. For example: "NUCLEUS" in the last row, seven backward letters.

Accepted Answer

The hidden four cell organelles are:VacuoleLeucoplastChromoplastPlastidThe solved maze is shown below:

Question 12

Question 10Name the followingThree essential parts of a living cell.Three types of plastids.Five parts of a nucleus.Two cellular structures found only in plant cells.Two types of cellular membranes on the basis of their permeability.

Accepted Answer

Cell Membrane, Cytoplasm, and NucleusChloroplasts, Chromoplasts, and LeukoplastsNuclear membrane, Nucleoplasm, Nucleolus, Chromatin Network, Nuclear PoreCell Wall and PlastidsFreely Permeable membrane (Cell Wall) and Selectively permeable membrane (Cell Membrane)

Question 13

Question 11Write one important role of the following :Nerve cellsGenesLeukoplastsMuscle cellsNucleus

Accepted Answer

Nerve cells conduct messages in the form of impulses between different parts of the body and the brain.Genes are responsible for transmitting characteristics from parents to offsprings.Leukoplasts store starch, fats and proteins in plant cells.Muscle cells are responsible for movement of body parts. It is the ability of the muscle cells to contract and relax.Nucleus regulates and coordinates various life processes of the cell.

Question 14

Question 12Define the terms given below :CellCytologyProtoplasmCytoplasmChloroplast

Accepted Answer

Cell — A cell can be defined as the basic structural and functional unit of all living things.Cytology —	Cytology is the study of cells, encompassing their structure, function, and interactions with their environment.Protoplasm — Protoplasm is the living substance of the cell. It is made up of the cytoplasm and nucleus.Cytoplasm — The cytoplasm is a semi-liquid (viscous), colourless and translucent substance. It is found between the nucleus and the cell membrane.Chloroplast — Chloroplasts are green plastids, that trap the solar energy for photosynthesis.

Cell — The Structure and Functions

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