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The Fundamental Unit of Life

Description: The Fundamental Unit of Life, Test-1
Number of Questions: 40
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Which of the following cell organelles is bound by a single membrane?

  1. Nucleus

  2. Lysosome

  3. Mitochondria

  4. Chloroplast


Correct Option: B
Explanation:

 Option (2) is correct.

Plant cell wall is composed of an important substance known as ___________.

  1. cellulose

  2. ATP

  3. DNA

  4. chitin


Correct Option: A
Explanation:

The most important features distinguishing the cells of plants from those of animals is the presence of cell wall in plants. This wall protects the cellular contents. A plant's cell wall is composed of several compounds among which cellulose is the most important. Cellulose is made up of molecules of the sugar glucose. Cellulose molecules are united into fibrils (layers of fibres), which form the structural framework of the wall. Other components of cell walls are lignin (provide rigidity) and waxes (reduce water loss from cells).

Which of the following statements about cells is not true?

  1. Animal cell has centrally placed nucleus.

  2. Animal cell is prokaryotic in nature.

  3. Cellulose provides structural strength to plants.

  4. Both animal cell and plant cell contain nucleus with chromosome.


Correct Option: B
Explanation:

Animal cell is prokaryotic in nature - False statement. Animal cell has a well defined nucleus. So it is an eukaryote and not a prokaryote (without nucleus) . Therefore, (B) is the correct answer. 

RER looks rough under microscope because of the presence of

  1. fat molecules

  2. carbohydrates

  3. lipids

  4. ribosomes


Correct Option: D
Explanation:

RER looks rough under a microscope because it has particles called ribosomes attached to its surface.

Apart from the nucleus, DNA is also present in the __________.

  1. golgi apparatus

  2. ribosome

  3. mitochondria

  4. vacuole


Correct Option: C
Explanation:

Reason: DNA (Deoxyribonucleic acid) is present in the nucleus of the cell. Along with nucleus, DNA is also present in mitochondria and chloroplast (in plants) but not in golgi apparatus, ribosomes and vacuole.. Mitochondria and chloroplast are referred to as strange organelles in the sense that they have their own DNA and ribosomes involved in protein synthesis. Therefore, both organelles are able to make some of their own protein. Therefore (C) is correct answer. 

Functional segments of DNA are _______.

  1. RNA

  2. chromosomes

  3. genes

  4. peptides


Correct Option: C
Explanation:

Genes - Functional segments of DNA are called genes which regulates the process of development of a cell. Functional segments mean that the information encoded within the DNA structure of a gene directs the manufacture of proteins that carry out life supporting activities. 

If a cell is placed in isotonic solution, it will

  1. shrink

  2. plasmolyse

  3. swell

  4. remain unchanged


Correct Option: D
Explanation:

If the medium has exactly the same water concentration as the cell; there will be no net movement of water across the cell membrane. Such a solution is known as isotonic solution. The cell will remain of the same size.

When a cell is placed in a hypertonic solution, the contents of the cell shrink away from the cell wall. This process is known as ___________.

  1. membrane biogenesis

  2. plasmolysis

  3. turgidity

  4. transpiration


Correct Option: B
Explanation:

Reason: Hypertonic - high solute (salt) concentration and low water level outside the cell. If the medium has lower concentration of water than the cell, meaning that it is very concentrated solution; the cell will lose water by exosmosis. Such a solution is known as hypertonic solution. (Osmosis - is the passage of water from a region of high water concentration through a semi-permeable membrane to a region of low water concentration. Thus, osmosis is a special case of diffusion through a semi permeable membrane).

More water will leave the cell through cell membrane than enters it. Therefore, the cell shrinks. When a living plant cell loses water through osmosis there is shrinkage of the contents of the cell away from cell wall since it is rigid. This phenomenon is known as Plasmolysis (Plasma = protoplasm, lysis - Breakdown) 

Plant cells differ from animal cells in the ________.

  1. presence of chromosomes

  2. presence of large central vacuole

  3. presence of mitochondria

  4. presence of lysosomes


Correct Option: B
Explanation:

Reason: Presence of chromosomes, presence of mitochondria (power house of the cell) and presence of lysosomes are similar in both plants and animals. The difference between the two lies in the nature of vacuoles.

Vacuoles are small sized animal cells while large size in plant cells. The central vacuole of some plant cells may occupy 50 - 90% of the cell volume. In plant cells, vacuoles are full of cell sap (which is made up mostly of water containing various dissolved sugar, salts and other chemicals) and provides turgidity and rigidity to the cell. Many substances of unimportant in life of plant cell are stored in vacuoles. 

The cell organelle that is a large network of membrane bound tubes and sheets is the _________.

  1. vacuole

  2. chloroplast

  3. mitochondria

  4. endoplasmic reticulum


Correct Option: D
Explanation:

Endoplasmic Reticulum - is a large network of membrane bound tubes and sheets. It looks like long tubules or round or oblong bags (Vesicles). They are of two types viz. Rough ER and Smooth ER. It always forms a network system in a cell. 

Which of the following is not a multicellular organism?

  1. Paramecium

  2. Fish

  3. Cockroach

  4. Pea plant


Correct Option: A
Explanation:

Reason: Multicellular - made up of many cells

Fish, Cockroach and pea plant - are examples of animals, insects and plants which are multicellular.

Paramecium - is an example of protozoans which are a type of Protist (unicellular eukaryotic organism). Therefore, Paramecium is a unicellular organism as it is made up only one cell.   

Organisms which have a well defined nucleus with a nuclear membrane are known as

  1. prokaryotes

  2. unicellular

  3. eukaryotes

  4. multicellular


Correct Option: C
Explanation:

Nucleus has a double layered covering called nuclear membrane. It is composed of DNA and protein. DNA molecules (Deoxyribonucleic acid) contain the information necessary for constructing and organising cells. Eukaryotes is the correct answer. Organisms with cells having a nuclear membrane are called eukaryotes, e.g. plants, animals.

Which of the following statements is not true?

  1. The size of prokaryotic cell is smaller than eukaryotic cell.

  2. Prokaryotic cell has a single chromosome.

  3. Cell membrane of a eukaryotic cell bears respiratory enzymes.

  4. Nucleus is bound by nuclear membrane in eukaryotic cell.


Correct Option: C
Explanation:

Cell membrane of a eukaryotic cell bears respiratory enzymes. Respiratory enzymes is an enzyme, such as oxidases, that transfer electrons from its substrate to molecular oxygen. During cellular respiration, cell membrane bears respiratory enzyme in prokaryotic cells but in eukaryotes cell, membrane lacks respiratory enzyme. In case of eukaryotic cell, respiratory enzymes are present in mitochondrial membrane. 

Which of the following organisms can change its shape?

  1. Amoeba

  2. Plant

  3. Bacteria

  4. Algae


Correct Option: A
Explanation:

Amoeba has no definite shape or size because it uses amoeboid movement, as a form of locomotion. They can create extensions of their body wall called pseudopodia (false feet) that helps them to locomote or capture prey. 

Movement of water across the plasma membrane from the region of lower concentration to the region of higher concentration is known as _______.

  1. diffusion

  2. plasmolysis

  3. osmosis

  4. active transport


Correct Option: C
Explanation:

Osmosis - is the movement of water from a region of high water concentration or low solute concentration to low water concentration or high solute concentration through a semi-permeable membrane. Thus, osmosis is a special case of diffusion through a semi permeable membrane. (Membrane which allows the entry and exit of only water and not solute). So, it is the correct answer. 

Which of the following materials is not stored in leucoplasts?

  1. Starch

  2. Oils

  3. Pigments

  4. Proteins


Correct Option: C
Explanation:

Reason: Pigments are stored in chromoplasts and chloroplasts (stores green pigments).

Which of the following cell organelles determines the development of cell and the shape it will exhibit on maturity?

  1. Vacuole

  2. Nucleus

  3. Mitochondria

  4. Lysosomes


Correct Option: B
Explanation:

Nucleus - plays a central role by determining the way the cell will develop and what form it will exhibit at maturity, by directing the chemical activities of cell. This is because nucleus enclose chromosomes which are composed of DNA and protein. Fundamental segments of DNA are called genes which regulate the process of development of a cell. 

The water like substance of the cell is known as _____________.

  1. mitochondria

  2. cytoplasm

  3. lipids

  4. ribosomes


Correct Option: B
Explanation:

Cytoplasm - is the fluid content inside the plasma membrane but outside the nuclear membrane. It also contains many specialized cell organelles. It is water like substance of cell. If we stain cheek cells or onion peel cells with methylene blue nucleus will take up the stain & appear as a dense structure whereas cytoplasm does not take up the stain. 

The undefined nuclear region of a prokaryotic cell is known as

  1. nucleolus

  2. nucleoid

  3. vesicle

  4. cisternae


Correct Option: B
Explanation:

Nucleoid: In bacteria (prokaryotes), the nuclear region of the cell is poorly defined due to the absence of nuclear membrane. Such an undefined nuclear region containing only nucleic acids is called a Nucleoid. 

Chloroplasts are important for ___________ in plants.

  1. photosynthesis

  2. animal respiration

  3. reduction

  4. membrane biogenesis


Correct Option: A
Explanation:

Photosynthesis - is a process by which green plants make their own food. Photosynthesis occurs in leaves and green stems within specialized cell organelle called chloroplasts as they contain green pigment (chlorophyll) which is required for the process of making food (photosynthesis). 

The spontaneous movement of gases across a permeable membrane takes place by ______________.

  1. diffusion

  2. osmosis

  3. plasmolysis

  4. reverse osmosis


Correct Option: A
Explanation:

spontaneous (occurring naturally) movement of gases across a permeable membrane from a region of high concentration to the region of low concentration is known as diffusion.

e.g. Carbon dioxide (CO2) (Which is a cellular waste required to be excreted out by the cell) accumulates in high concentrations inside the cell. In the cell's external environment, the concentration of carbon dioxide (CO2) is low as compared to that inside the cell. As soon as there is difference in concentration of CO2 inside and outside a cell, CO2 moves out of the cell from a region of high concentration to a region of low concentration outside the cell by the process of diffusion. Similarly oxygen (O2) enters the cell by the process of diffusion when the level or concentration of oxygen inside the cell decreases.

Which of the following structures is absent in an animal cell?

  1. Mitochondria

  2. Plastid

  3. Cytoplasm

  4. Cell membrane


Correct Option: B
Explanation:

Plastid - are present only in plant cells. Plastid containing pigment chlorophyll are known as chloroplasts which are important for photosynthesis in plants. Photosynthesis does not occur in animals. 

Rod shaped structures in nucleus visible at the time of cell division are known as ____________.

  1. DNA

  2. Genes

  3. Ribosomes

  4. Chromosomes


Correct Option: D
Explanation:

Chromosomes - In a cell which is not dividing, DNA is present as a part of chromatin material. Chromatin material is visible as entangled mass of thread like structures, But whenever the cell is about to divide, the chromatin material gets organized into chromosomes. Chromosomes are composed of DNA and protein. 

The shape and size of a cell is related to its ____________.

  1. appearance

  2. nucleus

  3. functions

  4. location


Correct Option: C
Explanation:

Reason: Cells vary in shape and size. The smallest cell, a type of bacterium known as Mycoplasma, measures 0.0001 mm in diameter. Amongst the largest cells are nerve cells. These cells can exceed 3 m in length. Along with the differences in size, cells are present in different shapes. In humans outermost skin cells are flat while nerve cells are elongated. In multicellular organisms shape and size of the cell is mainly dependent on its job or functions.

For example - flat skin cells pack tightly into a layer that protects the underlying tissue from invasion by bacteria. The numerous extensions from a nerve cell enable it to connect to several other nerve cells in order to send and receive messages rapidly. 

A system of membrane bound vesicles of golgi apparatus which are arranged parallel to each other in bundles is known as _______.

  1. cisterns

  2. golgi body

  3. golgi complex

  4. lysosome


Correct Option: A
Explanation:

Golgi apparatus consists of a system of membrane bound vesicles arranged approximately parallel to each other in bundles or stacks, called cisterns. These membranes often have connections with the membrane of endoplasmic reticulum and therefore constitute another portion of a complex cellular membrane system. 

Energy requirements of cell are fulfilled by __________.

  1. DNA

  2. genes

  3. ribosome

  4. ATP


Correct Option: D
Explanation:

ATP - Adenosine tri phosphate, molecule found in all living organisms that is the main immediate source of usable energy for the activities of the cell. ATP (Adenosine tri phosphate) is provided in the form of energy by the cell organelle- mitochondria. 

The full form of DNA is _________.

  1. Deoxyribonucleic Acid

  2. Dioxyribonucleic Acid

  3. Diribonucleic Acid

  4. Deribonucleic Acid


Correct Option: A
Explanation:

Deoxy - Removal of oxygen 

DNA is the genetic material found in all living organisms. Functional unit of DNA is called genes which regulates the process of development of a cell. All characters of individual are dependent on the types of genes. DNA is made up of deoxyribose sugar which is a fine carbon sugar (one atom of oxygen is removed from the ribose sugar). It also consists of nucleic acid. Nucleic acid are made up of bases, sugar and phosphate group. Bases are of 4 types in DNA consisting of Adenine (A), Thymine (T), Guanine (G) and Cytosine (C).(B), (C) and (D) are wrong terms.

Plant cells do not burst when kept in isotonic solution due to the presence of _____________.

  1. vacuole

  2. plastids

  3. cell wall

  4. nucleus


Correct Option: C
Explanation:

Reason: If the medium surrounding the cell has a higher water concentration than of the cell, meaning that the outside solution is very dilute, the cell will gain water by osmosis. Such a solution is known as hypotonic solution. The net result is that water enters the cell. The cell will swell up.

Vacuole - are small sized in animal cells while large size in plant cells. The central vacuole of some plant cells may occupy 50 - 90% of the cell volume. In plant cells, vacuoles are full of cell sap (which is made up mostly of water containing various dissolved sugar, salts and other chemicals).

Plastids- are present only in plant cells. Plastid containing pigment chlorophyll are known as chloroplasts which are important for photosynthesis in plants. Photosynthesis does not occur in animals.

Cell wall - Plant cells are rigid because of presence of cell wall made up of cellulose which is lacking in animal cell. This is the reason why plant cells do not burst and become turgid when placed in hypotonic solution whereas animal cells burst off when placed in hypotonic solution as cell wall is absent in them.

Nucleus encloses the chromosome in both plants & animals.

A cell placed in a _________ solution will shrink.

  1. isotonic

  2. hypertonic

  3. hypotonic

  4. monotonic


Correct Option: B
Explanation:

Hypertonic - high solute (salt) concentration and low water level. If the medium has lower concentration of water than the cell, meaning that it is very concentrated solution the cell will lose water by exosmosis. Such a solution is known as hypertonic solution.

More water will leave the cell through cell membrane than enters it. Therefore, the cell will shrink. When a living plant cell loses water through osmosis there is shrinkage of the contents of the cell away from cell wall. This phenomenon is known as Plasmolysis (Plasma = protoplasm, lysis - Breakdown) 

Which of the following is a unicellular organism?

  1. Bacterium

  2. Fungus

  3. Plant

  4. Animal


Correct Option: A
Explanation:

Reason: Bacterium belong to the kingdom Monera which are composed of unicellular organisms. Fungus: They are multicellular organisms belonging to kingdom animalia. Plants & Animals: They are multicellular eukaryotes. 

Which cell component is missing in prokaryotes?

  1. Cell membrane

  2. Mitochondria

  3. Cytoplasm

  4. Ribosome


Correct Option: B
Explanation:

Mitochondria - is a membrane bound organelle and prokaryotes do not have membrane bound organelles. 

Which of the following cell organelles do not contain DNA?

  1. Lysosomes

  2. Plastid

  3. Nucleus

  4. Mitochondria


Correct Option: A
Explanation:

Lysosomes - do not carry genetic information. They act as a waste disposal system in the cell. Lysosomes help to keep the cell clean by digesting any foreign material as well as worn out cell organelles. This is the reason why they are also known as “suicidal bags” Therefore the correct answer for this question is a Lysosome.

Which of the following structures is present only in plant cell?

  1. Ribosome

  2. Chloroplast

  3. Nucleus

  4. Plasma membrane


Correct Option: B
Explanation:

Chloroplast - Animals are heterotrophs which are dependent on others for food. Chloroplast are present only in plants as they are autotrophs and synthesize their food with the help of chlorophyll through the process of photosynthesis. 

Which cell organelle is known as 'the powerhouse' of the cell?

  1. Lysosmes

  2. Plastids

  3. Mitochondria

  4. Vacuoles


Correct Option: C
Explanation:

Mitochondria - are known as powerhouses of the cell” as they provide energy in the form of ATP (Adenosine Tri phosphate) for various chemical activities in the cell. Mitochondria have two membrane covering. The outer membrane is porous (permeable-permitting the movement of fluid or gases through it) while inner membrane is deeply folded. These folds create a large surface area for ATP-generating chemical reactions.

What serves as a fluid in which various cell organelles are embedded?

  1. Cytoplasm

  2. Nucleus

  3. Lysosome

  4. Vacuole


Correct Option: A
Explanation:

Cytoplasm - Present both in plants and animals. The cytoplasm is a fluid containing organelles with specialized functions and organelles are present both in plants & animals. 

Chromosomes are composed of _________.

  1. DNA and vitamins

  2. DNA and proteins

  3. DNA and lipids

  4. proteins and lipids


Correct Option: B
Explanation:

Reason: Nucleus contains chromosomes, which are visible as a rod shaped structures only when the cell is about to divide chromosomes composed of DNA and protein. DNA (Deoxyribose nucleic acid) helps in carrying information from parents to next generation. DNA is negatively charged and proteins associated with it are positively charged. The role of protein is to pack DNA. Vitamins or lipids cannot be used to pack DNA.Therefore (B) is correct answer 

Who observed the cell for the first time?

  1. Robert Hooke

  2. Schleiden

  3. Robert Brown

  4. Schwann


Correct Option: A
Explanation:

Cell was first discovered by Robert Hooke in 1665. He observed the cells in a cork slice with the help of a primitive microscope.

Which of the following options is a common feature between prokaryotic and eukaryotic cell?

  1. presence of nuclear membrane

  2. presence of single chromosome

  3. presence of cytoplasm

  4. presence of respiratory enzymes on cell membrane


Correct Option: C
Explanation:

Presence of cytoplasm -Present both in prokaryotes and eukaryotes. The cytoplasm is a fluid containing organelles with specialized functions and organelles.

Animal cells differ from the plant cells in the way that they do not have ____________.

  1. ribosome

  2. mitochondria

  3. nucleus

  4. cell wall


Correct Option: D
Explanation:

Cell Wall - Plant cells are rigid because of presence of cell wall made up of cellulose which is lacking in animal cell. 

Plasma membrane is made up of __________.

  1. vitamins and lipids

  2. proteins and lipids

  3. vitamins and proteins

  4. minerals and proteins


Correct Option: B
Explanation:

Reason: Plasma membrane is a thin molecular layer that surrounds all living cells. The plasma membrane separates the cell from its surroundings and protects it from changes in its environment. The plasma membrane is primarily composed of 2 types of molecules.

(1)        Lipids - Which are fats or oil molecules. Lipids help in transporting fat soluble substances across membrane.

(2)        Proteins - Help in transporting substances across the membrane.

            In most cells, plasma membrane is about 40% of Lipids and 60% of protein.

Vitamins like fat soluble (Vitamin A, D, E, K) or water soluble (Vitamin B, C) are not able to perform functions like lipids and proteins.Therefore they are not present in cell membrane. However, Carbohydrates along with protein e.g. glycoprotein are present in cell wall.

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