Cell Structure MCQ Quiz - Objective Question with Answer for Cell Structure - Download Free PDF

The correct answer is Protein synthesis.

Key Points

• Ribosomes are membranous granular structures present in the cytoplasm.
• They were first observed under an electron microscope as dense particles by George Palade in the year 1953.
• Ribosomes are the site for ''protein synthesis'' so they are also called the ''protein factory'' of the cell.
• There are two types of ribosomes

1. Eukaryotic ribosomes - 80s - occurs in the cytoplasm of eukaryotic cell
2. Prokaryotic ribosomes - 70s - occur in the cytoplasm as well as are associated with the cell membrane of prokaryotic cell.

• The subunits of the ribosomes are:
  • 80s ribosomes - are made of 60s and 40s subunits.
  • 70s ribosomes - are made of 50s and 30s subunits.

Important Points

• Composition of the structure of ribosome:
• They are composed of ribonucleic acid (RNA) and proteins

The correct answer is Cellulose.

• Plant cell walls are primarily made of cellulose.

Key Points

• Cellulose is the most abundant macromolecule on Earth.
  • Cellulose fibers are long, linear polymers of hundreds of glucose molecules.
  • These fibres aggregate into bundles of about 40, which are called microfibrils.

Additional Information

• Carbohydrates are the sugars, starches, and fibres found in fruits, grains, vegetables, and milk products.
  • A carbohydrate is a biomolecule consisting of carbon (C), hydrogen (H), and oxygen (O) atoms.
• Lipids are molecules that contain hydrocarbons and make up the building blocks of the structure and function of living cells.
  • A lipid is a biomolecule that is soluble in nonpolar solvents.
• A lipoprotein is a biochemical assembly whose primary function is to transport hydrophobic lipid also known as fat molecules in water, as in blood plasma or other extracellular fluids.
  • It consists of a Triglyceride and Cholesterol centre, surrounded by a phospholipid outer shell, with the hydrophilic portions oriented outward towards the surrounding water and lipophilic portions oriented inward toward the lipid centre.

The correct answer is Cells of a tissue have similar Structure.

Explanation:

Cells: The cell is the basic structural, functional, and biological unit of all known organisms.

• There are different shapes of the cells.
• The size and shape of the cells might be different in different organism.
• Some cells have a nucleus (Eukaryotic cells) while the other does not have a defined nucleus (prokaryotic cells).

Tissues:  A tissue is a group of similar cells performing a specific function. These tissues further made organs and later organ system

⇒ The correct option in the above statements are - cells of tissue have a similar Structure.

The correct answer is Cytoplasm.

Key Points

• Cytoplasm
  • Cytoplasm is the jelly - like substance present inside the cell.
  • It is jelly - like, because of its semi permeable characteristic.
  • It exists within the cell membrane.
  • Cytoplasm is extranuclear that means it does not exist within the cell’s nucleus.

Additional Information

• Cell wall
  • The cell wall is the outer covering of a cell.
  • It surrounds the plasma membrane of plant cells and provides tensile strength and protection against mechanical and osmotic stress.
  • The cell wall is present in plant cells and absent in animal cells.
• ​Plasma membrane
  • Plasma membrane, also called the cell membrane is mainly composed of lipids and proteins.
  • The major lipids are arranged in a bilayer and called as phospholipids.
  • Plasma membrane also contains cholesterol.
  • Cell membranes also possess protein and carbohydrate as per Biochemical investigation.
  • The ratio of lipid and protein varies in different cell types.
    • For example, in human beings, the membrane of the erythrocyte has approx 40 per cent lipids and 52 per cent protein.
• Plasma
  • Plasma is the largest component of blood, comprising about 55% of its overall content.
  •  Along with water, plasma carries salts, hormones and enzymes.
  • The main purpose of plasma is to transport nutrients, hormones, and proteins to the parts of the body that need them.
  • Plasma is the largest part of the blood. It makes up more than half (about 55%) of its total content. When separated from the rest of the blood, plasma is a pale yellow liquid that contains water, salts, and enzymes.

CONCEPT:

Non-Membrane Bound Organelles

• Organelles are specialized structures within a cell that perform specific functions.
• Non-membrane bound organelles are not enclosed by a lipid membrane and are found in both prokaryotic and eukaryotic cells.
• Ribosomes are an example of non-membrane bound organelles, and they play a crucial role in protein synthesis.
• These organelles are composed of ribosomal RNA (rRNA) and proteins.
• Ribosomes can be found free-floating in the cytoplasm or attached to the rough endoplasmic reticulum in eukaryotic cells.

EXPLANATION

• Ribosome: A non-membrane bound organelle found in both eukaryotic and prokaryotic cells. It is responsible for protein synthesis.
• Golgi Complex: A membrane-bound organelle found only in eukaryotic cells. It is involved in packaging and sorting of proteins.
• Microbodies: Membrane-bound organelles like peroxisomes, present only in eukaryotic cells.
• Lysosome: A membrane-bound organelle containing digestive enzymes, found in eukaryotic cells.
• Thus, the correct answer is Ribosome, as it is non-membrane bound and is present in both prokaryotic and eukaryotic cells.

Therefore, the correct option is Ribosome.

The correct answer is Protein synthesis.

Key Points

• Ribosomes are membranous granular structures present in the cytoplasm.
• They were first observed under an electron microscope as dense particles by George Palade in the year 1953.
• Ribosomes are the site for ''protein synthesis'' so they are also called the ''protein factory'' of the cell.
• There are two types of ribosomes

1. Eukaryotic ribosomes - 80s - occurs in the cytoplasm of eukaryotic cell
2. Prokaryotic ribosomes - 70s - occur in the cytoplasm as well as are associated with the cell membrane of prokaryotic cell.

• The subunits of the ribosomes are:
  • 80s ribosomes - are made of 60s and 40s subunits.
  • 70s ribosomes - are made of 50s and 30s subunits.

Important Points

• Composition of the structure of ribosome:
• They are composed of ribonucleic acid (RNA) and proteins

• Photosynthesis: It is the process by which green plants and some other organisms use sunlight to synthesize nutrients from carbon dioxide and water. In this process, plant the chlorophyll, carbon dioxide, water, sunlight, and release oxygen.
• Synthesis of Fatty acids occurs in the cytoplasm.

The correct answer is Both chloroplast and mitochondria

Concept:

Theory of endosymbiosis:-

• Symbiotic relationship, where one organism lives inside the other, is known as endosymbiosis. 
• The theory proposed that mitochondria and chloroplasts evolved from engulfed prokaryotes.
• A large anaerobic bacteria engulfed an aerobic prokaryote, which then formed an endosymbiotic relationship with the host, gradually developing into a mitochondrion.
• It is believed that chloroplasts originated from a cyanobacterial endosymbiont.

Explanation:

Similarities between Prokaryotic cells, Mitochondria, and Chloroplast:

• Mitochondria and chloroplast are of the same size as prokaryotic cells.
• Mitochondria and prokaryotic cells both have their own circular DNA.
• The ribosome of bacteria, mitochondria, and chloroplasts have a 70S type of ribosome.
• Divides by binary fission.

The correct answer is Cellulose.

• Plant cell walls are primarily made of cellulose.

Key Points

• Cellulose is the most abundant macromolecule on Earth.
  • Cellulose fibers are long, linear polymers of hundreds of glucose molecules.
  • These fibres aggregate into bundles of about 40, which are called microfibrils.

Additional Information

• Carbohydrates are the sugars, starches, and fibres found in fruits, grains, vegetables, and milk products.
  • A carbohydrate is a biomolecule consisting of carbon (C), hydrogen (H), and oxygen (O) atoms.
• Lipids are molecules that contain hydrocarbons and make up the building blocks of the structure and function of living cells.
  • A lipid is a biomolecule that is soluble in nonpolar solvents.
• A lipoprotein is a biochemical assembly whose primary function is to transport hydrophobic lipid also known as fat molecules in water, as in blood plasma or other extracellular fluids.
  • It consists of a Triglyceride and Cholesterol centre, surrounded by a phospholipid outer shell, with the hydrophilic portions oriented outward towards the surrounding water and lipophilic portions oriented inward toward the lipid centre.

The correct answer is Lysosome.

Key Points

• ​Lysosome:
  • Lysosomes are an important cell organelle found within eukaryotic animal cells.
  • Due to their peculiar function, they are also known as the “suicide bags” of the cell.
  • Lysosomes work as the waste-discarding structures of the cell by processing undesirable materials and degrading them, both from the exterior of the cell and waste constituents inside the cell.
  • But sometimes, the digestive enzymes may end up damaging the lysosomes themselves, and this can cause the cell to die.
  • This is termed autolysis, where “auto” means “self” and “lysis” means “the disintegration of the cell by the destruction of its cell membrane“

Additional Information

• Peroxisomes:
  • It is a microbody.
  • In-plant it helps in photorespiration.
  • In animals concerned with peroxide metabolism.
• Glyoxysomes: These are the special type of peroxisomes found in plants & some fungi.
• Polysome: Many ribosomes may associate with a single mRNA to form multiple copies of a polypeptide simultaneously.
  • Such strings of ribosomes are termed as Polysome.

The correct answer is Cellulose.

• The epidermis is the protective outer layer of clonally related cells covering all plant organs.
• It is made up of cellulose, hemicelluloses, and pectin.

Important Points

• Functions of the cell wall in the plant:
  • Regulates and controls the direction of cell growth.
  • Providing strength, structural support, and maintaining the shape of the cell.
  • It supports the entry of smaller molecules moving freely.

Additional Information

• Cell Membrane is present in all organisms including plants.
  • It is also known as the plasma membrane.
  • It is a semi-permeable membrane composed of lipids and proteins.

Key Points

Explanation:

• Ribosomes are known as protein factories because they are the main site of protein synthesis. The molecule of RNA which is a component of the ribosome organelle is called ribosomal RNA.
• Ribosomes are composed of ribonucleic acids and proteins.
• It is made up of two subunits-
  • Large subunits- join amino acids to form a polypeptide chain.
  • Small subunits- reads RNA.

So, each subunit is made up of one or more of ribosomal RNA and ribosomal proteins.

Explanation:

• The cell is the structural and functional unit of life. 
• The size & shape of cells vary with their functions, for example, Mycoplasmas, the smallest cells, are only 0.3 μm in length while bacteria could be 3 to 5 μm.
• Human red blood cells are about 7.0 μm in diameter
• Osteocytes, the bone cells are the longest-lived cells.
• The largest cell of the Human body is the Female gamete i.e. Ovum, however, according to the options given Neuron will be considered the correct answer. 
• Nerve cells or neurons are the longest body cells

Mistake Points

• The largest body cell in humans is the Female gamete - ovum but here it is not given in the options, so according to the options neurons will be considered correct as it is the longest body cell

The correct answer is Mitochondria and Plastids.

Key Points

• Both mitochondria and chloroplasts contain their own DNA and ribosomes.
• Both plant cells and animal cells possess mitochondria. It has its own DNA and plays a met role in the synthesis of enzymes and the production of energy.
• Mitochondria are membrane-bound cell organelles (mitochondrion, singular) that generate most of the chemical energy needed to power the cell's biochemical reactions.
  • Chemical energy produced by the mitochondria is stored in a small molecule called adenosine triphosphate (ATP).
• Chloroplasts are plant cell organelles that convert light energy into relatively stable chemical energy via the photosynthetic process.
  • By doing so, they sustain life on Earth. Chloroplasts are plant cell organelles that convert light energy into relatively stable chemical energy via the photosynthetic process.

EXPLANATION:

A cell is the fundamental structural and functional unit of all living organisms. Anton van Leeuwenhoek discovered the first living cell in 1674.

• Inside each cell is a dense membrane-bound structure called the nucleus. 
• The nucleus is the largest organelle in the cell that contains thread-like structures called chromosomes on which genes (DNA) are present.
• A gene is the basic physical and functional unit of heredity. Genes are made up of DNA.
• The nucleolus is the round irregular structures present inside the nucleus.
• The ribosome is not a part of the nucleus. They are found floating in the cytosol or attached to the endoplasmic reticulum.

​

The Correct Answer is Option 3 i.e Mitochondria.

• Golgi apparatus:
  • This cell organelle is primarily responsible for storage, processing, and packaging proteins.
  • Golgi Apparatus is found within the cytoplasm of a cell and are present in both plant and animal cells.
• Mitochondria:
  • Mitochondria is the cell organelle also called the Powerhouse of the cell.
  • It generates energy molecules called ATP or Adenosine Triphosphate.
• Cell membrane:
  • The cell membrane, also called the plasma membrane, is found in all cells and separates the interior of the cell from the outside environment.
  • The cell membrane regulates the transport of materials entering and exiting the cell.
• Nucleus:
  • It is a membrane-bound organelle that contains the genetic material of organisms.