Class 9 Science Chapter 5 MCQ Online Tests for 2020-2021
| Class: 9 | Science |
| Chapter: 5 | The Fundamental Unit of Life |
| Contents: | MCQ Online Tests with Answers |
Class 9 Science Chapter 5 MCQ with Answers for 2020-21
Class 9 Science Chapter 5 MCQ Online Test contains about 75 questions in all with answers and explanation. New questions will be added time to time to increase the question bank. All the questions are taken from NCERT Books for 9th Standard Science issued for academic session 2020-2021.
Q1
Living cells were discovered by
[A]. Robert Hooke
[B]. Purkinje
[C]. Leeuwenhoek
[D]. Robert Brown
Answer: Option C
Explanation:In the year 1670, Anton Van Leuwenhoek, a Dutch biologist discovered the living cell when he looked at the pond water under the microscope, he made of lenses.
Q2
Read the following sentences carefully, and choose the incorrect one:
[A]. The mitochondria synthesize energy rich compounds (ATP), they are known as powerhouse of the cell.
[B]. Mitochondria are present in bacteria and the red blood cells of mammals.
[C]. ATP stands for the organic compound adenosine triphosphate.
[D]. Mitochondria are able to make some of their own proteins, so they are regarded as semi-autonomous organelles.
Answer: Option B
Explanation:Mitochondria are absent in bacteria and the red blood cells of mammals.
Q3
The only cell organelle seen in prokaryotic cell is
[A]. Mitochondria
[B]. Ribosomes
[C]. Plastids
[D]. Lysosomes
Answer: Option B
Explanation:Unlike eukaryotic cell, a prokaryotic cell lacks membrane bound organelles like plastids, mitochondria and endoplasmic reticulum but smaller and randomly scattered ribosomes are seen.
Q4
In the last year board examination, Rahul were asked a question where he had to choose the statement which was/were correct? Will you be able to answer this question?
[A]. The chromatin material is a thin, thread like intertwined mass of chromosome material and composed of the genetic substance DNA and proteins.
[B]. DNA store all the information necessary for the cell to functions to grow and to reproduce further cells of the next generation.
[C]. Chromosomes are thread like structures usually present in the nucleus that become visible only during cell division.
[D]. All the above.
Answer: Option D
Explanation:Here, are all the statements are correct. Hence, your answer will be option [D].
Q5
Recently, in a science class test, you are asked a question where you have to say whether the statements are correct or not?
[A]. Cell wall permits the plant cell to become turgid.
[B]. In plant cells, there occurs a rigid cell wall which lies outside the plasma membrane.
[C]. The plant cell wall, thus, consists of tiny cellulose fibres called microfibrils.
[D]. The cell walls of adjacent cells are glued together by the plasmodesmata.
Answer: Option D
Explanation:The cell walls of adjacent cells are glued together by the plasmodesmata.
Q6
Cell wall of which one of these is not made up of cellulose?
[A]. Bacteria
[B]. Hydrilla
[C]. Mango tree
[D]. Cactus
Answer: Option A
Explanation: Plant cells, in addition to the plasma membrane, have another rigid rotor covering called the cell wall. The cell wall lies outside the plasma membrane. The plant cell wall is mainly composed of cellulose. Cellulose is a complex substance and provides structural strength to plants. Bacteria is not a plant therefore its cell wall is made up of “Peptidoglycan”.
Q7
Rahul is doing his homework which is given by his teacher. Would you help him to choose the incorrect sentences?
[A]. The prokaryotic cells usually range between 1 to 10 micrometers (μm).
[B]. The largest size of an elephant is due to the larger cells present in its body.
[C]. Amoeba proteus is biggest among the unicellular organisms.
[D]. The smallest cells are those of mycoplasma gallisepticum, an organism intermediate between virus and bacteria.
Answer: Option B
Explanation:The volume of a cell is fairly constant for a particular cell type and is dependent to the size of an organism.
For example, kidney or liver cells are approximately the same size in a bull, horse and mouse. The difference in the total mass of the organ or organisms dependent on the number, not on the volume of the cells.
The cells of an elephant are not necessarily larger than those of other tiny animals or plants. The large size of an element is due to the larger number of cells present in its body.
Q8
Puja is writing some statements but she confused to know whether the statements are correct or not? If you know the answer to this question, then tell her:
[A]. In prokaryotic cell division take place by fission or budding whereas in eukaryotic cell division occurs by meiotic cell division.
[B]. In prokaryotic cell nucleus is present whereas in eukaryotic cell nucleus is absent
[C]. Prokaryotic cell contains a single chromosome whereas eukaryotic cell contains more than one chromosome.
[D]. None of the above.
Answer: Option B
Explanation:In prokaryotic cell nucleus is absent whereas in eukaryotic cell nucleus is present.
Q9
Which of these options are not a function of Ribosomes?
[A]. It helps in manufacture of protein molecules, and It helps in manufacture of enzymes.
[B]. It helps in manufacture of enzymes, and It helps in manufacture of hormones.
[C]. It helps in manufacture of hormones, and It helps in manufacture of starch molecules.
[D]. It helps in manufacture of starch molecules, and It helps in manufacture of protein molecules.
Answer: Option C
Explanation:Ribosomes are dense, spherical and granular particles which remains freely in the matrix or remain attached to endoplasmic reticulum. They are not bound by membrane and are present in both prokaryotic and eukaryotic cells. They play important role in synthesis of proteins. All enzymes are proteins but all hormones are not proteins.
Q10
Chromosomes are made up of
[A]. DNA
[B]. Protein
[C]. DNA and protein
[D]. RNA
Answer: Option C
Explanation:Chromosomes are thread like structure as usually present in the nucleus which becomes visible only during cell division. Each chromosome is made up of two components.
i)Deoxyribonucleic acid (DNA)
ii) Proteins (e.g. histones and acidic proteins)
These consists of two (unreplicated) or four (duplicate) arms and a primary constriction or centromere which gives them a particular shape due to its position. The paired condition of chromosome is called diploid and unpaired chromosome are said to be haploid.
What do understand by Hypertonic solution?
If the medium has a lower concentration of water than the cell, meaning that it is a very concentrated solution, the cell will lose water by osmosis. Such a solution is known as a hypertonic solution.
What is Plasmolysis?
When a living plant cell loses water through osmosis there is shrinkage or contraction of the contents of the cell away from the cell wall. This phenomenon is known as plasmolysis.
Why are Lysosomes known as suicide bags?
During the disturbance in cellular metabolism, for example, when the cell gets damaged, lysosomes may burst and the enzymes digest their own cell. Therefore, lysosomes are also known as the ‘suicide bags’ of a cell.
How does Mitochondria make their own protein?
Mitochondria have their own DNA and ribosomes. Therefore, mitochondria are able to make some of their own proteins.
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