KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells

Students can download Class 8 Science Chapter 5 Study of Cells Important Questions, KSEEB Class 8 Science Important Questions and Answers helps you to revise the complete Karnataka State Board Syllabus and to clear all their doubts, score well in final exams.

Karnataka State Syllabus Class 8 Science Important Questions Chapter 5 Study of Cells

Question 1.
What is the body of living beings made of?
Answer:
The body of all living beings is made up of very small units called cells. The cells are the building blocks of the body of living beings.

Question 2.
How do you classify living beings on the basis of the number of cells in their body?
Answer:
Living beings are classified on the basis of the number of cells in their body as unicellular organisms and multi-cellular organisms.

KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells

Question 3.
What are unicellular organisms? Give four examples.
Answer:
Organisms whose body is made up of only one cell are called unicellular organisms. E.g. Amoeba, Euglena, Paramecium, Entamoeba, etc.

Question 4.
What are multi-cellular organisms? Give four examples.
Answer:
Organisms whose body is made up of many cells are called multi-cellular organisms. E.g. Hydra, Ant, Elephant, Human being, etc.

Question 5.
Classify the following as unicellular and multi-cellular organisms: hydra, amoeba, ant, diatom.
Answer:

  • Unicellular organisms: Amoeba, diatom
  • Multi-cellular organisms: Hydra, ant.

Question 6.
Why are diatoms called unicellular organisms?
Answer:
Most diatoms have only one cell in their body. This is why diatoms are called unicellular organisms.

Question 7.
Define a cell.
Answer:
The basic structural and functional unit of all living organisms is called a cell. It is the smallest unit of life.

Question 8.
Why is the cell called structural and functional unit of life?
Answer:
All the functions of our body are done by cells. Life processes such as respiration, digestion, etc., occur in the cell. The smallest living being has only one cell in its body and it carries out all the basic life processes in one cell only. Therefore, a cell is the functional unit of life.

Cell is called the structural unit of life because life starts from a cell. All living organisms are made up of cells. Cells are arranged to form tissues, tissues group together to form organs, organs form organ system, which finally forms an organism in multi-cellular organisms. Thus, cell also forms the structural unit of life.

KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells

Question 9.
Write the five levels of structural organization found in multi-cellular organisms.
Answer:
Chemicals form organic molecules from which cells are formed. Cells organize into tissues. Tissues organize to form organs. Several related organs form an organ system. All organ systems will together form an organism.
KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells 1

Question 10.
Who discovered the cell?
Answer:
The cell was discovered by Robert Hooke in 1665. He observed a piece of thin cork under a microscope which he had designed. He saw honeycomb-like structures in it. He called them ‘cells’.

Question 11.
Who put forth the cell theory in 1839?
Answer:
Two scientists M.J. Schleiden and Theodore Schwann together put forward the cell theory in 1839.

Question 12.
State the points of the cell theory proposed by Schleiden and Schwann.
Answer:
According to the cell theory proposed by Schleiden and Schwann:

  • All organisms are composed of one or more cells.
  • All cells are produced by the division of preexisting cells.

Question 13.
What is cytology?
Answer:
The branch of science that deals with the study of cells is called cytology (cell biology).

KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells

Question 14.
Why are there different types of cells in multi-cellular organisms?
Answer:
The body of an organism has to carry out different functions. Each function requires specific type of cells. For example, the skin in our body is made up of specialised epidermal cells. Cardiac muscles are also composed of simple contractile cells that are linked together in the heart’s wall. The nerve cells, also called as the neurons, are responsible for carrying messages to the different body parts. This is why there are different types of cells in multi-cellular organisms.

Question 15.
Give some examples to show the relationship between ike shape of cells and their function
Answer:
KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells 2
KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells 3

Question 16.
What is the unit commonly used to express the size of a cell?
Answer:
The unit commonly used to express the size of a cell is ‘micron’. One micron is equal to one micrometre. 1 micron = 10-6 metre.

Question 17.
Express micron in millimetre.
Answer:
One micron is equal to one-thousandth of a millimetre.
1 micron = \(\frac{1}{1000}\) mm = 10-3 mm.

Question 18.
We see organisms in different sizes. What is the difference in size of organisms due to? Explain with an example.

OR

Is the difference in the size of an organism due to the large size of the cells or large number of cells?
Answer:
The difference in size of organisms is due to the difference in the number of cells in the body. For instance, the size of cells in the body of an ant is similar to that of an elephant. The elephant is much bigger in size than an ant simply because the elephant has more cells in its body than an ant.

Question 19.
Which is the best device to observe clearly a cell and its components?
Answer:
A cell and its components can be best observed with the help of an electron microscope. Some cells can be observed under a compound microscope but it may not show the components of the cell.

Question 20.
What is an electron microscope? What is the magnification of objects in an electron microscope?
Answer:
Any microscope which employs electron beams in place of light and uses special type of lenses called electron lenses for producing bigger images is called an electron microscope. An electron microscope magnifies an object about 20000 times.

KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells

Question 21.
What is a compound microscope? Describe its structure briefly. What does the magnifying power of microscope tell?
Answer:
A microscope that uses visible light and has two lens systems of which one is the objective and the other is the eye piece is called a compound microscope. The two lens systems, largely convex lenses, are mounted inside a tube.

The objective is held towards and close to the object to be observed and the eye piece is held close to the eye. The magnifying power of a microscope tells how many times larger an object appears than its actual size when viewed under it.

Question 22.
How do you find the magnifying power of a compound microscope? Explain with an example.
Answer:
In a compound microscope, both the objective and the ey epiece produce magnification. However, the magnifying power of the objective is higher than that of the eyepiece. The magnifying power of a compound microscope is calculated by multiplying the magnifying power of the objective by the magnifying power of the eyepiece.

Consider a compound microscope whose objective magnifies 40 times. We write this as 40x. Let the eyepiece magnify 10 times. We write this as 10x. Now the magnifying power of the compound microscope is 40 × 10 = 400. This means the image produced by the microscope appears 400 times larger than its actual size.

Question 23.
A school has a compound microscope. The magnifying power of its objective is 100x and that of its eyepiece is 10x. Find the magnification produced by the microscope.
Answer:
Magnification produced by the microscope is given by the product of the magnification of the objective and the magnification of the eyepiece, i.e., 100 × 10= 1000. The magnifying power of the microscope is 1000x.

Question 24.
Draw a neat diagram of the microscopic view of cells in onion peel.
Answer:
KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells 4

Question 25.
Describe how we can observe the cells in an onion peel using a compound microscope.
Answer:
Take a piece of a layer of onion. Peel off a thin epidermal layer from it. Put this on a drop of water taken on a glass slide. Put a drop of iodine or any other suitable staining solution over the onion layer. Place the slide under a compound microscope. Observe the cells by looking through the eyepiece. You will see brick-like structures arranged one beside the other.

KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells

Question 26.
Mention the three prominent components of a cell. Explain each component briefly.
Answer:
The three prominent components of a cell are the cell membrane, cytoplasm and the nucleus.
1. Cell membrane:
This encompasses all its components. It is also called plasma membrane. This membrane separates the contents of the cell from the outside environment. It helps to maintain the shape of the cell. It also controls the movement of selected substances in and out of the cell.

2. Nucleus:
Nucleus is the largest structure inside a cell. It is present in all eukaryotic cells. It is enclosed by a membrane that separates the nucleus from the rest of the contents of the cell. The nucleus contains the genetic material. It also controls all the activities of the cell.

3. Cytoplasm:
All the contents of the cell outside the nucleus and enclosed within the cell membrane constitute the cytoplasm. It is basically the substances that fill the cell outside its nucleus. It largely consists of a jelly-like fluid along with a number of small structures called cell organelles.

Question 27.
What is the other name of cell membrane?
Answer:
The cell membrane is also called plasma membrane.

Question 28.
Cell membrane is called a semi permeable membrane. Why?
Answer:
Cell membrane is called a semi permeable membrane because it allows only some substances to pass through it and not others. In this sense, the cell membrane is selectively permeable.

KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells

Question 29.
Draw a neat diagram of an animal cell and label the parts.
Answer:
KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells 5

Question 30.
Draw a neat diagram of a plant cell and label the parts.
Answer:
KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells 6

Question 31.
List any four differences between a plant cell and an animal cell.
Answer:

Plant cell Animal cell
1. Plant cell is covered by a thick cell wall in addition to the cell membrane. Animal cells do not have cell walls. They have only cell membrane.
2. Plastids are present. Plastids are absent.
3. Vacuoles are present in large numbers and they are larger in size. Vacuoles are present in fewer numbers and are smaller in size.
4. Centrosomes and centrioles are not found in plant cells Centrosomes and centrioles are present in animal cells

Question 32.
Which are the two main processes by which materials move in and out of a cell through the cell
membrane?
Answer:
The two main processes by which materials move in and out of a cell through the cell membrane are diffusion and osmosis.

Question 33.
What is diffusion? Give an example.
Answer:
The natural movement of molecules from a region of higher concentration to a region of lower concentration is called diffusion. The spreading of fragrance of agarbatti in a room is an instance of diffusion.

Question 34.
Describe a simple activity to show the process of diffusion.
Answer:
Take some water in a beaker. Drop a crystal of potassium permanganate into it. Observe the changes. The potassium permanganate molecules move from the crystal slowly and get gradually distributed in water. Here, the molecules of potassium permanganate have moved from a region of higher concentration to the regions of lower concentration. This is an instance of diffusion.
KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells 7

Question 35.
How does oxygen move into a cell? How does carbon dioxide move out of the cell?
Answer:
The oxygen moves into the cell and the carbon dioxide moves out of the cell by the process of osmosis. The concentration of oxygen is higher outside the cell compared to its concentration inside the cell. Therefore, oxygen moves into the cell through the cell membrane by the process of osmosis. Similarly, the concentration of carbon dioxide is higher inside the cell than outside. Therefore, carbon dioxide diffuses out of the cell through the cell membrane.

KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells

Question 36.
What is osmosis?
Answer:
The movement of molecules from a region of higher concentration to a region of lower concentration
Describe a simple activity to show the process of osmosis. through a semi-permeable membrane is called osmosis.

Question 37.
Answer:
KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells 8
Take a potato and peel off its skin. Make a cup shaped cavity in it. Pour concentrated sugar solution into the cavity. Place the potato half immersed in water taken in a container. Mark the level of sugar solution. Leave it for about half an hour. Now observe the level of the sugar solution. The level of sugar solution would have gone up.

This is due to the movement of water molecules from outside into the cup through the semi-permeable membrane of the potato cells. Here, water molecules have moved from a region of higher water concentration to a region of lower water concentration through the membrane. However, the membrane does not allow the sugar molecules to move through it. Therefore, the movement of molecules is selective. This is an instance of osmosis.

Question 38.
What happens when an empty potato cup is kept in a trough with water? Why?
Answer:
Nothing happens when an empty potato cup is kept in a trough containing water. Osmosis does not take place here as there is no force that can induce the movement of water through the semi-permeable membrane.

Question 39.
Distinguish between diffusion and osmosis.
Answer:

Diffusion Osmosis
1. This is a process in which molecules move from a region of higher concentration to a region of lower concentration. This is a process in which molecules move from a region of higher concentration to a region of lower concentration through a semi permeable membrane.
2. Diffusion is based on random movement of molecules due to concentration gradient. Osmosis is selective diffusion. The membrane selectively allows only certain particles but not others.

Question 40.
Why are diffusion and osmosis instances of ‘passive transport’?
Answer:
Both diffusion and osmosis are categorized as instances of ‘passive transport’. This is because, no external energy is required for the flow of molecules from a region of higher concentration to a region of lower concentration.

Question 41.
What is active transport? Give two organs where active transport occurs in our body.
Answer:
The movement of molecules from a region of lower concentration to a region of higher concentration which takes place with the expenditure of energy is called ‘active transport’.

In our body, active transport occurs in the heart and kidneys. Sodium moves from a region of lower concentration (blood) to a region of higher concentration (heart tissues) in our heart. This process requires energy. Similarly, active transport occurs in kidneys.

The salts present in the kidney tubules in very low concentration are absorbed back into the blood stream where the concentration is higher by ‘active transport’.

KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells

Question 42.
Distinguish between diffusion and active transport.
Answer:

Diffusion Active transport
1. This is the movement of molecules from a region of higher concentration to a region of lower concentration. This is the movement of molecules from a region of lower concentration to a region of higher concentration.
2. Requires no expenditure of energy. Requires the expenditure of energy.

Question 43.
What is cell wall? What is it made of?
Answer:
The rigid outermost cell layer surrounding the cell membrane of cells of plants is called cell wall. It is mainly made of cellulose.

Question 44.
What is the function of cell wall found in plant cells?
Answer:
The cell wall in plants performs several functions. The basic function is that it serves as a protective membrane for the more delicate cell membrane and to the contents of the cell. Thus, it protects the cells from injuries and weather fluctuations. It determines the shape of the plant cell by providing strength and rigidity to the cell. It prevents drying up of cells and prevents too much of water coming into the cytoplasm.

Question 45.
What is cytoplasm? What is it made of?
Answer:
The jelly-like substance found between the nucleus and the cell membrane which includes various substructures is called cytoplasm.

Cytoplasm is made of a jelly-like substance which is largely made of water. It also contains a number of non-living and living structures. The living structures are called organelles like endoplasmic reticulum, mitochondrion, golgi complex, lysosomes, plastids, etc. The non-living substances (inclusions) include starch grains, oil droplets, calcium carbonate, resins and gum. Some of these materials are used as food while others are cell secretions and waste products.

Question 46.
State any two functions of cytoplasm.
Answer:
Cytoplasm is the seat of all cellular activities. It is the place where several substances like proteins, carbohydrates and fatty acids are synthesized. It is in the cytoplasm that the oxidation of glucose takes place which provides energy for the bodily activities. It is the storehouse for raw materials. Cytoplasm also ensures the distribution of nutrients and enzymes in the cell. Cytoplasm exchanges materials with the environment.

Question 47.
What are organelles? Name the prominent organelles of a cell.
Answer:
Organelles are specialised structures found in the cytoplasm of cell. Some of the prominent organelles found inside a cell include nucleus, mitochondria, golgi complex, centriolcs, chloroplasts, endoplasmic reticulum and lysosomes.

Question 48.
How are the living components of a cell classified?
Answer:
The living components of a cell are known as organelles. They are grouped into two categories. They are

  1. Membranous organelles and
  2. Non-membranous organelles.

Question 49.
What are membranous organelles? Give two examples.
Answer:
Organelles that are covered by membranes are known as membranous organelles. E.g. Plastids, Lysosomes, Mitochondria, etc.

KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells

Question 50.
What are non-membranous organelles? Give two examples.
Answer:
Organelles that are not covered By membranes are called non-membranous organelles. E.g. Ribosomes, Centrioles.

Question 51.
Classify the following organelles as membranous and non-membranous organelles: Centrioles, Mitochondrion, Ribosomes, Plastids, Golgi complex.
Answer:

  1. Membranous organelles: Mitochondrion, Plastids, Golgi complex
  2. Non-membranous organelles: Centrioles, Ribosomes.

Question 52.
Find out the differences between an organ and an organelle.
Answer:
The differences between an organ and an organelle are as follows:

Organ Organelle
1. A group of related tissues that perform a specific function or group of functions in the body of an organism is called an organ. Any substructure of a cell that performs specific function or functions is called an organelle.
2. Several related organisms constitute an organ system. The organelles constitute a single cell in the body of an organism.
3. Organs are usually macroscopic. Organelles are microscopic.
4. An organ performs specific functions inside the body of an organism. Organelles perform specific functions inside a cell.

Question 53.
What is endoplasmic reticulum? What are its functions?
Answer:
KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells 9
A membranous organelle consisting of a network of branching tubules found in the cytoplasm of eukaryotic cells extending from the nuclear membrane to the cell membrane is called endoplasmic reticulum. It is also scattered in the cytoplasm.

Endoplasmic reticulum forms the supporting framework of the cell. It is involved in the synthesis and transport of cellular materials within the cell.

Question 54.
What is mitochondrion? Where is it located?
Answer:
A membranous organelle in which the processes of respiration and energy production occur is called mitochondrion. Mitochondria arc present in large numbers in eukary otic cells. They are located within a cell outside the nucleus.

KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells

Question 55.
How many mitochondria are usually present in a cell?
Answer:
A cell usually contains 30 to 40 mitochondria. However, their number depends on the function of the cell. They are often concentrated in the more active regions of the body where energy requirement is higher.

Question 56.
Flight muscle cells in insects contain thousands of mitochondria. Give reason.
Answer:
Flight muscles in insects are the regions of intense activity and hence require large amount of energy. This is why flight muscles have thousands of mitochondria which help to produce the required energy.

Question 57.
Explain briefly the structure of mitochondria.
Answer:
KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells 10
A mitochondrion is bound by a double membrane. These membranes are thinner than the cell membrane. The outer membrane is smooth. The inner membrane is folded. The foldings of the inner membrane arc called cristae. Inner membrane encloses a fluid known as matrix.

Question 58.
What is the major function of mitochondria?

OR

Why is the mitochondria called the powerhouse of the cell?
Answer:
The chief function of mitochondria is to produce energy. This is why mitochondrion is called the power house of the cell.

Question 59.
Where is the energy produced in the mitochondria stored?
Answer:
The energy produced in the mitochondria is stored in a molecule called adenosine triphosphate (ATP).

Question 60.
What is golgi complex?
Answer:
A membranous organelle in eukaryotic cells in the cytoplasm consisting of flat discs with expanded ends (vesicles) is called golgi complex.

Question 61.
What is golgi complex made of?
Answer:
Golgi complex consists of flat discs with expanded ends (vesicles).

KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells

Question 62.
What is the main function of the golgi complex?
Answer:
The main function of the golgi complex is to secrete chemicals required for cellular activities.

Question 63.
What are lysosomes? State their function.
Answer:
A membranous organelle in the cytoplasm of eukaryotic cells containing digestive enzymes is called lysosomc. The main function of lysosomes is to digest organic substances present in the cell and destroy the cell when it becomes old, weak, damaged or diseased.

Question 64.
Why are lysosomes called ‘suicide bags’ of the cell?
Answer:
Lysosomes are called ‘suicide bags’ of the cell because they destroy their destroy cell when it becomes old, weak, damaged or diseased.

Question 65.
What are plastids? What is their function?
Answer:
A number of small membranous organelle consisting of pigments and found in the cytoplasm of plant cells are known as plastids. Plastids are involved in the synthesis and storage of food in photosynthesizing organisms such as green plants.

Question 66.
What are the plastids that do not contain colour pigments called? Where are they generally found?
Answer:
Plastids which do not contain coloured pigments are called leucoplasts. Leucoplasts are generally found in those regions of the plant which are not exposed to sunlight such as tender roots.

Question 67.
Mention some of the plant parts where leucoplasts are found. What is their function?
Answer:
Leucoplasts are generally found in roots which are less exposed to sunlight. The main function of leucoplasts is to store food.

Question 68.
What are chromoplasts?
Answer:
Plastids in plants that contain coloured pigments other than green are known as chromoplasts.

KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells

Question 69.
What is the role of chloroplast in a plant cell?
Answer:
Chloroplasts are responsible for photosynthesis in green plants.

Question 70.
What are chloroplasts? Name the pigment present in them.
Answer:
Plastids in plant cells that contain green pigments are known as chloroplasts. The green pigment present in chloroplasts is called chlorophyll.

Question 71.
Draw a neat labelled diagram of a chloroplast present in green plants.
Answer:
KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells 11

Question 72.
Briefly describe the structure of chloroplast.
Answer:
A chloroplast is a membranous organelle covered by a double membrane. The inner membrane encloses a matrix – stroma and grana. The grana contains a green coloured pigment called chlorophyll. Chlorophyll helps to trap sunlight.

Question 73.
What are ribosomes? What is their function?
Answer:
A minute, grain-like structure composed of RNA and protein that is found attached to the endoplasmic reticulum and nuclear membrane in the cytoplasm of living cells is called a ribosome. The function of ribosomes is protein synthesis.

Question 74.
Why are ribosomes called protein factories of the cell?
Answer:
Ribosomes play an important role in the synthesis of proteins. Hence, they are referred to as protein factories of the cell.

Question 75.
Which organelle in an animal cell is useful during cell division?
Answer:
Centrioles help in the formation of spindle fibres during cell division.

KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells

Question 76.
What are vacuoles?
Answer:
The spaces or cavities present in the cytoplasm which are covered by a membrane are called vacuoles.

Question 77.
State the function of

  1. Centrioles
  2. Vacuoles.

Answer:

  1. Centrioles help in cell division.
  2. Vacuoles store food, excess water and waste products.

Question 78.
Distinguish between food vacuoles and contractile vacuoles.
Answer:
Vacuoles which store food and help in digestion are food vacuoles. Vacuoles which help in the removal of excess water are contractile vacuoles.

Question 79.
What is meant by nucleus of a cell? What does it contain?
Answer:
A spherical organelle found within a cell that contains hereditary information is called the nucleus. The nucleus of a cell consists of nucleoplasm and a network of chromatin.

Question 80.
Briefly describe the structure of the nucleus with the help of a suitable diagram.
Answer:
The nucleus is covered by a double membrane called nuclear membrane. The membrane encloses a fluid called nucleoplasm. This membrane separates the contents of the nucleus from the cytoplasm. The chromosomes of the cell are also found within the nucleus in the form of a network of chromatin.

A chromosome consists of a hereditary or genetic material called DNA. DNA in turn consists of genes. The nucleus also contains a dense round¬shaped structure called the nucleolus. This plays an important role in protein synthesis.
KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells 12

Question 81.
Why is the nucleus of a cell called the brain of the cell?
Answer:
The nucleus controls all the activities of the cell. Eukaryotic cells cannot exist without the nucleus. Hence it is called the brain of the cell.

Question 82.
What are chromosomes? How many chromosomes are present in a human cell?
Answer:
A thread-like structure of nucleic acids and protein found in the nucleus of eukaryotic cells, carrying genetic material is called chromosome. A human cell typically contains 46 chromosomes.

KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells

Question 83.
What are genes? Mention their importance.
Answer:
A hereditary unit consisting of a sequence of DNA that occupies a specific location on a chromosome and determines a particular characteristic of an organism is called gene.

Genes earn traits from the parents to the offspring. Each gene determines a particular characteristic of an organism. For example, height of a person, colour of the skin, colour of the eyes. etc.

Question 84.
What are chromatins?
Answer:
The network of thread-like structures found inside the nucleus of a cell is called chromatin.

Question 85.
Which are the organelles that are found in large numbers in the following cells:

  1. Muscle cells
  2. White blood cells
  3. Leaf cells, and
  4. Pancreatic cells?

Answer:

  1. Muscle cells: Mitochondria
  2. White blood cells: Lysosomes
  3. Leaf cells: Flastids
  4. Pancreatic cells: Golgi complex.

Question 86.
Diagrams of two different cells are given below. Which one of the two is a plant cell? Support your answer. Also,

  1. Name the parts 1, 2, 3 and 4
  2. Write the functions of 1 and 3
  3. Draw a diagram to show the structure of 4 and label the parts.

Answer:
KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells 13
The cell given to the right is a plant cell. This is because it contains cell wall and plastids. It also contains a large vacuole. These features are not present in an animal cell.
1. 1 – Golgi complex, 2 – Centrosomes, 3 – Cell wall, 4 – Plastids.

2. The part marked 1 is the Golgi complex. It is involved in cellular secretions. The part marked 3 is the cell wall. It provides protection to the cell.

3.
KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells 14

KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells

Question 87.
List the major differences between a plant cell and an animal cell with respect to cell wall,plastids, vacuole and centrioles.
Answer:
KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells 15

Question 88.
0.9% sodium chloride solution is good and balanced to RBC. A lab technician accidentally places
a sample ofRBCs in 1.8% sodium chloride solution. What happens? Why?
Answer:
0.9% sodium chloride solution is normal saline. This is the same concentration that we find inside a red blood cell. When such a saline is given, water goes in and comes out at the same rate from a red blood cell. Thus the size of the cell does not change. If 1.8% saline is given, water comes out of the cell at a faster rate. Thus the red blood cell shrinks.

Multiple Choice Questions

Question 1.
A cell lacking in nucleus, also lacks
(a) plasma membrane
(b) mitochondria
(c) chromosome
(d) vacuole
Answer:
(b) mitochondria

KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells

Question 2.
Chloroplast in a plant cell
(a) controls the cell
(b) stores water and minerals
(c) makes carbohydrates by photosynthesis
(d) controls what enters and leaves the cell
Answer:
(c) makes carbohydrates by photosynthesis

Question 3.
Osmosis can be described as the movement of
(a) liquid from an area of high concentration to an area of low concentration
(b) a solution through a semi-permeable membrane into an area of lower concentration
(c) water through a semi-permeable membrane from an area of more, to an area of less water
(d) molecules from a region of lower concentration to a region of higher concentration with the expenditure of energy.
Answer:
(c) water through a semi-permeable membrane from an area of more, to an area of less water

Question 4.
Plant cells differ from animal cells in that plant cells have
(a) an endoplasmic reticulum
(b) a central vacuole
(c) Golgi complex
(d) organelles
Answer:
(b) a central vacuole

Question 5.
In the cells of which one of the following is the cell wall absent?
(a) mushroom
(b) moss
(c) fern
(d) mosquito
Answer:
(d) mosquito

Question 6.
The organelle of the cell that releases energy through respiration is
(a) Golgi complex
(b) Mitochondrion
(c) Lysosome
(d) Chloroplast
Answer:
(b) Mitochondrion

KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells

Question 7.
Which structures are present in both animal and plant cells?
(a) Vacuole, nucleus and cell membrane
(b) Nucleus,cell wall, cytoplasm
(c) Nucleus, cell membrane, cytoplasm
(d) Cell membrane, chloroplast, cell wall
Answer:
(c) Nucleus, cell membrane, cytoplasm

Question 8.
Which one of the following parts of a cell is non-living?
(a) cell wall
(b) mitochondria
(c) cell membrane
(d) lysosome
Answer:
(a) cell wall

Question 9.
Which is NOT a characteristic of chloroplasts?
(a) A chloroplast is surrounded by a double membrane.
(b) Chlorophyll absorbs solar energy that is used to make carbohydrates
(c) Chloroplasts include both Stroma and Grana.
(d) Chlorophyll is found in the fluid Stroma of the chloroplast.
Answer:
(d) Chlorophyll is found in the fluid Stroma of the chloroplast.

Question 10.
The smallest organelle among the following is
(a) lysosome
(b) nucleolus
(c) ribosome
(d) mitochondrion
Answer:
(b) nucleolus

KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells

Fill In The Blanks

1. The instrument that led to the understanding of the cell is microscope
2. The organelle which controls the various activities of the cell is nucleus
3. The organelle which is called the ‘kitchen of the plant cell’ is plastids
4. The site of protein synthesis in a cell is ribosomes
5. The main chemical component of the cell wall is cellulose
6. The organelle responsible for cellular respiration and energy conversion is mitochondria
7. The jelly-like fluid material that fills the space between nucleus and plasma membrane in a cell is known as cytoplasm
8. The semi-permeable membrane that encloses the contents of an animal cell is called cell membrane/plasma membrane
9. The basic unit of life is cell
10. The natural movement of particles from a region of higher concentration to a region of lower concentration is called diffusion
11. ________ are the sites of respiration in a cell. Mitochondria

KSEEB Class 8 Science Important Questions Chapter 5 Study of Cells

Match The Following

Question 1.

A B
1. Storage room of the cell a. Chloroplasts
2. Gateway of the cell b. Golgi complex
3. Solar panels of the cell c. Vacuole
4. Packages of hereditary information d. Cell wall
e. Chromoplast
f. Cell membrane
g.  Chromosome

Answer:
1 – c, 2 – f, 3 – a, 4 – g.

Question 2.

A B
1. Protein factories of the cell a. Cell
2. Suicide bags of cells b. Mitochondria
3. Powerhouse of the cell c. Chromosomes
4. Vehicles of inheritance d. Lysosomes
5. Structural and functional units of an organism e. Plastids
f. Ribosomes

Answer:
1 – f, 2 – d, 3 – b, 4 – c, 5 – a.