Multiple Choice Type
Which one of the following cell organelles is correctly matched with its function?
- Ribosomes- Synthesis of proteins ✓
- Mitochondria- Secretion of enzymes
- Plasma Membrane- Freely permeable
- Centrosome- – Carries genes
All life starts as-
- an egg
- a single cell ✓
- a gene
- a chromosome
Which one of the following is found both in cells of a mango plant and a monkey?
- cell wall
- cell membrane ✓
A plant cell can be identified from an animal cell by the-
- Absence of centrosome ✓
- Presence of cell membrane
- Presence of vacuoles
- None of the above
Plant cell has a cell wall made of-
- Cellulose ✓
- Fatty acids
The cell organelle that helps in respiration of the cell is-
- Mitochondria ✓
Very Short Answer Type
Name the part of the cell concerned with the following?
- Liberation of energy
- Synthesis of proteins
- Transmission of heredity characters from parents to offspring
- Initiation of cell division
- Hydrolytic in function
- Entry of only certain substances into and out of the cell.
- Plasma membrane/cell membrane
State 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) Anthocyanins are the pigments of flowers, which are dissolved in cell-sap
How many chromosome pairs are found in human cells?
Normal human body cells contain 46 chromosomes, consisting of a pair of 23, one from each parent. Out of this, 22 pairs of chromosomes are autosomes – same in both males and females. The last pair of chromosomes is the sex chromosome and differs in males (XY) and females (xx).
What is the name of the chemical substance which constitutes the genes?
The chemical substance constituting the genes is DNA. It stands for de-oxy ribonucleic acid.
Match the items in column ‘A’ with those in column ‘B’
|Column A||Column B|
|Lysosomes||Covered by tonoplast|
|Anthocyanin||Dissolved in the cytoplasm|
|Column A||Column B|
|Vacuoles||Covered by tonoplast|
|Anthocyanin||Dissolved in the cytoplasm|
Fill in the blanks
Lysosomes consists of membranous sacs and secretes 40 types of digestive enzymes.
Centriole is surrounded by microtubules, located near the nucleus.
Very thin flexible, living membranes which is differently permeable, is called Plasma membrane.
More than 1000 chromosomes are found in the nucleus of certain Insects
Genes are heredity units.
Leucoplast is a plastid which stores starch.
Short Answer Type
It is said that the protoplasm cannot be analysed chemically. Why?
The protoplasm cannot be analysed chemically because it has complex organic and living cell organelles which can disintegrate if chemicals are added to analyse. Also due to complexity of physical and chemical properties the ultimate chemical nature of protoplasm cannot be determined.
What is the difference between an organ and an organelle?
|Size||Visible to the naked eyes, larger in size||Microscopic|
|Location||They are present throughout the body||Known as little organs, are found within the cell.|
|Function||Carry out functions of the entire body||Carry out functions within the cell|
|Example||Heart, Lungs, Liver||Ribosomes, Endoplasmic reticulum,Golgi complex|
Do you think the cells of an elephant would be larger than the cells of a rat? Explain
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.
Differentiate between the following pairs of terms-
- Protoplasm and cytoplasm
- Nucleolus and nucleus
- Centrosome and chromosome
- Cell wall and cell membrane
- Plant cell and animal cell
- Prokaryotes and eukaryotes
The differences are as follows-
Protoplasm and cytoplasm
|Protoplasm is the living matter of the cell. The total substance of a living cell-nucleus and cytoplasm||Mixture of insoluble and soluble organic compounds and water wherein different cell organelles are implanted.|
Nucleolus and nucleus
|It is present in the nucleus and is round-shaped nucleoli.||It is present in the cell and is a dense spherical structure. It comprises a network of thread-like structures known as chromatin fibres.|
Centrosome and chromosome
|Cytoplasm is close to the nucleus and it is a clear are. Here spindle fibres emerge during the process of cell division||They contain genes or hereditary data that transfer genetic traits from parents to offspring.|
|Found in animal cell only||They are found in the nucleus of both plant and animal cell|
Cell wall and cell membrane
|Cell wall||Cell membrane|
|Non-living rigid layer||Living, flexible membrane and thin|
|Composed of cellulose||Composed of lipoproteins|
Plant cell and animal cell
|Plant cell||Animal cell|
|Cell wall is definite and made of cellulose||No cell wall|
|Centrosome is absent||Centrosome is present|
|Plastids usually present||Plastids absent|
Prokaryotes and eukaryotes
|Cells contain primitive and undefined nucleus||Have a well-defined nucleus along with a nuclear membrane|
|Other than ribosomes, they do not contain any other cell organelle||Possess other cell organelles|
|Possess smaller ribosomes||Larger ribosomes|
|Example – Blue-green algae||Example – Humans|
Mention three features found only in plant cells and one found only in animal cells.
Given below are features found only in plant cell-
- Cell wall
- Large vacuoles
Following are the features that are observed in animal cells only:
- Centrosome is observed in animal cells only. Plants do not have centrosomes.
Why are the cells generally of a small size?
Cells are generally so little so that they can maximize their ratio of area to volume. They have to be ready to get the nutrients in and therefore the waste out quickly.The important point is that the area to the volume ratio gets smaller as the cell gets larger. Thus, if the cell grows beyond a particular limit, not enough material is going to be ready to cross the membrane fast enough to accommodate the increased cellular volume. That's why cells are so small.
Long Answer Type
What is the cell theory? Who propounded it and when?
The Cell Theory states three major points -
- The cell is the smallest unit of structure of all living thing
- The cell is the unit of function of all living things
- All cells arise from pre-existing cells.
The theory was propounded in 1839 by Schwann and Schleiden. Rudolf Virchow in 1858 made an additon to the cell theory by saying that all cells arise from pre-existing cells.
Mention the three differences between a living cell and a brick in a wall
Following are the differences between a living cell and a brick in a wall-
|The living structure is non-rigid||Living structure is rigid|
|Contains cellulose chiefly||Contains soil primarily|
|Is functional in nature, performs critical functions pertaining to life processes||Non-functional|
Name the plastid and pigment likely to be found in the cells of:
- Petals of sunflower
- Ripe tomato
- Skin of green tomato
- Cells of potato.
The following are the pigments and plastids that are found in these cells-
- Pigment — Xanthophyll
Plastid — Chromoplasts
- Pigment — Carotene
Plastid — Chromoplasts
- Pigment — Chlorophyll
Plastid — Chloroplasts
- Pigment — No pigment
Plastid — Leucoplasts
State the major functions of the following-
- Plasma membrane
- Golgi apparatus
- Asters of centrosome
- Glycogen granule
The major functions are as follows-
Plasma membrane —
(a) Separates contents of cell from its surroundings.
(b) Regulates the entry of certain solutes and ions.
(c) Maintains shape of the cell in animal cells.
(a) Protein synthesis
(a) Intracellular digestion.
(b) Destroy foreign substances.
(c) They are referred to as ‘suicidal bags’ as they destroy cell organelles when they turn old or are damaged.
(a) Controls the cell functions.
(b) Referred to as ‘power house of the cell’, as energy is stored in the form of ATP.
(c) Involved in cellular respiration to release energy.
(d) Bearers of genes.
Golgi apparatus(in animal cells) —
(a) Synthesis and secretion of enzymes, hormones,etc.
(b) Acrosomes of sperms are formed.
(a) Contains organelles perform multitude of functions.
(b) Performs all metabolic activities.
Asters of centrosome —
(a) Cell division – regulation and initiation.
(b) Spindle fibre formation.
(a) Passes genetic characteristics from parents to offspring.
Glycogen granule —
(a) Food for cells.
(a) Stores food, water, pigments and waste products.
(b) Renders turgidity to the plant cell.
List any six features found both in plant and animal cells.
Given below are the following six features found both in plant and animal cells
- Cell 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.
Given below are the sketches of two types of cells A and B.
- Which one of these is a plant cell? Give reason in support of your answer.
- List the cell structures which are common to both the types.
- Name the structures found only in plant cells and those found only in animal cells.
Figure B is a plant cell because in Figure B, the cell has a cell wall, a large vacuole and the vacuole is seen pushing the nucleus to the periphery.
Cell structures common to both the types in the figure are:
(d) Cell membrane
(f) Endoplasmic reticulum
(g) Golgi body
The structures found only in plant cells are:
(a) cell wall
The structures found only in animal cells are: