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

The correct answer is Protein synthesis.

Explanation

Ribosomes are small and complex structures within cells that are involved in one of the most vital processes needed for life i.e. protein synthesis. They link amino acids together in the order determined by messenger RNA (mRNA) molecules.

Here's some detailed information on Ribosomes:

Structure: Ribosomes are made up of two subunits: a larger one and a smaller one. Both of these subunits are composed of a special class of RNA known as ribosomal RNA rRNA and proteins.

• In eukaryotes, the larger subunit is known as the 60S subunit and the smaller one is the 40S subunit, together forming the complete 80S ribosome
• In prokaryotes, the smaller subunit is the 30S subunit, and the larger one is the 50S subunit, making an overall smaller 70S ribosome.

Function: The main function of ribosomes is to carry out protein synthesis. This process is also known as translation and involves decoding mRNA which was previously transcribed from the cell's DNA to build a chain of amino acids, which will become a protein. This means ribosomes are the site where the cell's genetic information is used to create proteins.

Location: Ribosomes are found both in the cytoplasm free ribosomes and attached to the endoplasmic reticulum ER, creating what is known as the rough ER. Free ribosomes typically synthesize proteins that function within the cytoplasm, while those associated with the ER synthesize proteins that are either exported from the cell, incorporated into the cell's membranes, or sent to lysosomes.

Conclusion Ribosomes are sites for protein synthesis.

The correct answer is cytologyKey Points

• Cytology is the study of individual cells of the body, in contrast to histology which is the study of whole human tissue.
  • The human body is made up of millions of cells and these can be sampled and viewed under a microscope after appropriate preparation to help diagnose medical conditions.
  • This involves looking at individual cells for abnormal changes in both the nucleus and the cytoplasm (body) of the cell.
  • The nucleus contains the genetic material that controls the cell and determines what type of cell it will become, but also controls its behavior.
  • Cytology is widely used in medicine for the prevention and diagnosis of disease.

Additional Information

• Robert Hooke was the first scientist to use the word 'cell' in 1665 when he looked at slices of cork through a lit compound microscope and observed very small, irregular boxes that reminded him of tiny rooms, or cells.
  • Hooke wrote about his findings and drew the structures he saw in his book Micrographia, which was published in 1665.
• The earliest cell theory was developed in 1838 by plant scientist Matthias Schleiden and animal scientist Theodor Schwann.
• They each came to the same conclusion that the living things they studied were composed of cells. 

The correct answer is Glicial cells

Key Points

• The cells of the nervous system that are supported, protected, and nurtured are called glial cells.
• Glial cells, also known as glia, surround neurons and provide support for and insulation between them.
• Glial cells are essential for the overall health of the nervous system, playing crucial roles in nutrient supply to nerve cells and maintenance of homeostasis.
• Unlike neurons, glial cells do not conduct electrical impulses. Their primary role is to support neurons.

Additional Information

The correct answer is : Cell Wall Key Points

• Cell Wall: The cell wall is a rigid layer present outside the plasma membrane in plant cells. It provides structural support, protection, and helps in maintaining the cell's shape. The primary component of most plant cell walls is cellulose, a complex carbohydrate. In contrast, animal cells lack a cell wall; they only have a plasma membrane, which is flexible. 
• Plastids: Plastids are organelles present only in plant cells. An example of a plastid is the chloroplast, which contains the pigment chlorophyll used in photosynthesis to convert light energy into chemical energy. Chloroplasts are a vital part of plant cells, enabling them to produce food. Plastids can also store food in the form of starch and can contain pigments that give flowers and fruits their colors. However, animal cells do not have plastids because they do not carry out photosynthesis.
• Mitochondria: Mitochondria are organelles that produce ATP (adenosine triphosphate), the energy currency of cells through a process called cellular respiration. These organelles are present in both plant and animal cells, so this option cannot be unique to plant cells.
• Lysosomes: Lysosomes are present in both plant and animal cells, even though their abundance in differing types of cells can vary. They are involved in intracellular digestion, breaking down waste materials, and cellular signaling. However, while they are widely recognized as a feature of animal cells, the presence, and role of lysosomes in plant cells have long been a subject of debate, with some evidence suggesting the existence of “lysosome-like” vacuoles.

The correct answer is i - b, ii - a, iii - c, iv - d

Key Points

• The cell physically expands, duplicates organelles, and creates the molecular building blocks it will require in subsequent stages during G1phase, also known as the first gap phase.
• The cell creates a full copy of the DNA in its nucleus during the S phase. Moreover, it makes duplicates of the centrosome, a structure that organises microtubules. During M phase, the centrosomes aid in the separation of DNA.
• The second gap phase, also known as the G2 phase, is a time of increased cell growth, protein and organelle production, and content reorganisation in preparation for mitosis.
• The cell's nuclear DNA condenses into its visible chromosomes during mitosis and is separated by the mitotic spindle, a specialised microtubule-based structure.

Additional Information

•  Stages of the cell cycle
  • ​A cell must grow, replicate its genetic material (DNA), and physically split into two daughter cells before it may divide.
  • The cell cycle is a structured, predictable series of actions that cells take to complete these goals.
  • Because the two daughter cells can restart the entire process from the beginning after each cycle, the cell cycle is a cycle rather than a linear pathway.

The correct answer is Nucleoid.

Key Points

• In prokaryotic organisms, the nuclear region is not surrounded by any membrane.
  • The undefined nuclear region lacking a nuclear membrane and containing only DNA without proteins in bacteria is called the nucleoid.
• Prokaryotic cells are primitive organisms.
  • In prokaryotes, the nucleoid contains all or most of the genetic material.
  • In prokaryotic cells, the nucleus is not well-defined because it is not surrounded by the nuclear membrane.

Additional Information

• A nucleosome is a section of DNA wrapped around a core of protein.
  • Inside the nucleus, DNA forms a complex with a protein called chromatin, which allows the DNA to condense into small amounts.
• A nucleus, as it relates to genomics, is a membrane-bound organelle within a cell that contains chromosomes.
  • A series of pores, or pores, in the nuclear membrane allow selective passage of certain molecules (such as proteins and nucleic acids) in and out of the nucleus.
• Nucleoproteins are a type of proteins that are associated with nucleic acids and ribosomes and lipoproteins, they often serve as lipid transport and storage proteins such as vitelline.
  • A nucleoprotein is a conjugated protein structure consisting of a protein linked to a nucleic acid, either DNA abbreviated as deoxyribonucleic acid or RNA abbreviated as ribonucleic acid.

Concept:

• Cells are the structural and functional unit of life.
• They exist in different shapes and sizes.
• The structure of a cell is directly proportional to its function.

Explanation:

• A cytoskeleton is found in the cytoplasm as a network of protein filaments.
• There are three types of cytoskeletons found in the cytoplasm- microtubules, microfilaments, and intermediate filaments.
• They are found only in eukaryotic cells.
• Cytoskeleton provides mechanical support to the cell and helps maintain the shape of the cell.
• They are important for cell division and movements inside the cell.
• They also function in supporting the cell organelle and allow cell motility.
• Intracellular transport is not carried out by the cytoskeleton.
• There are vesicles and certain motor proteins that help in intracellular transport.

So, the correct answer is option  i.e. Intracellular transport

Additional Information

•  Microtubules, Microfilaments, and intermediate filaments are proteinaceous structures to support the extensive system of membranes that collectively form the cytoskeleton of a cell.
• The microtubules occur in cilia, flagella, centrioles and basal bodies, mitotic apparatus, etc.
• The microfilaments are mainly composed of the globular protein actin but have filamentous protein myosin also.
• Microfilaments are involved in cytoplasmic streaming and amoeboid movements. 

The correct answer is golgi apparatus

Key Points

Golgi Bodies Functions:

• Its main function is the packaging and secretion of proteins.
• It receives proteins from Endoplasmic Reticulum. It packages it into membrane-bound vesicles, which are then transported to various destinations, such as lysosomes, plasma membrane or secretion.
• They also take part in the transport of lipids and the formation of lysosomes.
• Post-translational modification and enzymatic processing occur near the membrane surface in Golgi bodies, e.g. phosphorylation, glycosylation, etc.
• Golgi apparatus is the site for the synthesis of various glycolipids, sphingomyelin, etc.
• In the plant cells, complex polysaccharides of the cell wall are synthesised in the Golgi apparatus.

Additional Information

Golgi Apparatus:

• The Golgi apparatus has multiple names such as the Golgi complex or Golgi body.
• The name is given on the name of the scientist, who discovered the organelle, i.e. Camillo Golgi.
• It is found in all the eukaryotic cells, plants as well as animals.
• They are membrane-bound organelles present in the cytosol of the cell.
• The Golgi body comprises 5 to 8 cup-shaped, series of compartments known as cisternae. Cisternae is a flattened, disk-shaped, stacked pouches that make up the Golgi apparatus. A Golgi stack mostly contains 4 to 8 cisternae. However, ~60 cisternae are found in some protists. A mammalian cell contains ~40 to 100 stacks of cisternae.
• Animal cells generally contain around 10 to 20 Golgi stacks per cell, which are connected by tubular connections.
• Golgi complex is mostly found near the nucleus.

The correct answer is Cell wall.Key Points

• The cell wall is a rigid layer that surrounds the cell membrane of plant cells, bacteria, fungi, and some protists.
• It provides structural support and protection to the cell, and helps maintain its shape.
• The cell wall is made up of cellulose, a complex carbohydrate that gives it its strength and rigidity.
• The cell wall also has pores that allow for the exchange of water, nutrients, and gases between the cell and its environment.

Additional Information

• The cell membrane is a thin, flexible layer that surrounds the cell and separates its internal environment from the external environment.
  • It regulates the movement of substances in and out of the cell, and also plays a role in cell signaling and communication.
• Lysosomes are membrane-bound organelles that contain enzymes for breaking down and recycling cellular waste and foreign materials.
  • They are found in animal cells, but not in plant cells.
• The Golgi apparatus is an organelle that sorts, modifies, and packages proteins and lipids for transport within the cell or secretion outside the cell.
  • It is made up of a series of flattened, membrane-bound sacs called cisternae.

The correct answer is room.

Key Points

The word "cell" comes from the Latin word "cella", which means a small room or chamber.

• It was first discovered in the year 1665 by the English philosopher and architect named Robert Hooke.
• Later in the year 1839, two German Scientists, Matthias Schleiden and Theodor Schwann proposed the cell theory. According to this theory:
  • Every living organism is composed of one or more cells.
  • The cell is the fundamental unit of life.
  • Cells are the structural and functional organization in organisms.
  • All cells arise from pre-existing cells.
  • All biochemical processes are carried out by cells.
  • On the whole, cell biology is essential to all other biological sciences, including genetics, molecular biology, immunology, etc.

Additional Information

• Cell biology is about the cell, cell division and its functions. Every living species are composed of a cell. The human body comprises around a billion to trillion cells, which are mainly involved in different specialized functions. Their shape and size usually vary, and a single, minute cell alone can perform several functions to keep an organism healthy and alive.
• Cell or cellular biology, the sub-discipline of biology, mainly deals with the study of the cell, cell theory, different types of cell- unicellular, multicellular, cell organelles along with their functions, prokaryotes, eukaryotes, and different kinds of cellular processes.

Concept-

• Mitotic produced genetically identical cells, which are similar to the mother cells.
• Mitotic is also called equational division.
• Mitotic cell division is divided into the following four stages-
  • (a) Prophase  (b) Metaphase  (c) Anaphase  (d) Telophase

Explanation-

• At the beginning of the final stage of mitosis, i.e., telophase, the chromosomes that have reached their respective poles decondense and lose their individuality.
• The individual chromosomes can no longer be seen and chromatin material tends to collect in a mass in the two poles.
• This is the stage which shows the following key events-
  • Chromosomes cluster at opposite spindle poles and their identity is lost as discrete elements.

Hence in telophase, chromosome lost their identity.

Additional Information

• Mitosis or the equational division is usually restricted to the diploid cells only.
• Mitosis usually results in the production of diploid daughter cells with identical genetic complement.
• The growth of multicellular organisms is due to mitosis.
• A very significant contribution to mitosis is cell repair.

The correct answer is Golgi Apparatus.

Key Points

• Golgi Apparatus:
  • The Golgi apparatus has multiple names such as the Golgi complex or Golgi body.
  • The name is given on the name of the scientist, who discovered the organelle, i.e. Camillo Golgi.
  • It is found in all eukaryotic cells, plants as well as animals.
  • They are membrane-bound organelles present in the cytosol of the cell.
  • The Golgi body comprises 5 to 8-cup-shaped, series of compartments known as cisternae. Cisternae is a flattened, disk-shaped, stacked pouches that make up the Golgi apparatus. A Golgi stack mostly contains 4 to 8 cisternae. However, ~60 cisternae are found in some protists. A mammalian cell contains ~40 to 100 stacks of cisternae.
  • Animal cells generally contain around 10 to 20 Golgi stacks per cell, which are connected by tubular connections.
  • The Golgi complex is mostly found near the nucleus.

Additional Information

• Mitochondria.
  • The number of mitochondria in a single cell may be up to 50 to 5000.
  • The inner lumen of mitochondria contains ribosome phosphate particles and DNA molecules.
  • It has the potential to synthesize its own protein and oxidation of carbohydrates and fats are taken place with the help of enzymes in mitochondria.
  • This energy is stored in the form of ATP ( Adenosine Triphosphate ) so, these are known as the "Powerhouse of the cell".​
• Chloroplast:
  • The chloroplast is a double membrane-bound cell organelle.
  • Out of the two membranes, the inner membrane is relatively less permeable. (the outer membrane contains porins).
  • The space limited by the inner membrane is called the stroma.
  • Chloroplasts contain chlorophyll and carotenoid pigments which are responsible for trapping of light energy essential for photosynthesis.
  • The majority of chloroplasts are found in the mesophyll cells of the leaves.

• Chromosomes
  • Chromosomes are thread-like structures located inside the nucleus of animal and plant cells.
  • Each chromosome is made of protein and a single molecule of deoxyribonucleic acid (DNA).
  • Passed from parents to offspring, DNA contains the specific instructions that make each type of living creature unique.

Concept:

• Cell cycle refers to the series of changes that occur in a newly formed cell. It involves a cell's growth and division to form two daughter cells.

• The cell cycle comprises two stages - the Interphase and M phase.
• The M Phase represents the phase when the actual cell division or mitosis occurs. It is a short dividing phase.
• Interphase represents the phase between two successive M phases. It is a long non-dividing growing phase.
• Interphase can be divided into 4 steps: Gap 1 (G1), S (synthesis) phase, and Gap 2 (G2).

Important Points

• G₁ Phase - 
  • In a human cell, the G1  phase of the cell cycle lasts for approximately 11-12 hours.
  • During the G1 phase, the cell is metabolically active and continuously grows but does not replicate its DNA.
• S Phase - 
  • In a human cell, the S phase of the cell cycle lasts for about 8 hours.
  • S or synthesis phase marks the period during which DNA synthesis or replication takes place.
• G₂ Phase - 
  • The G2  phase of the cell cycle lasts for about 4 hours.
  • During the G2 phase, proteins are synthesized in preparation for mitosis while cell growth continues. 
• M Phase
  • The M phase of the cell cycle lasts for about 1 hour in a human cell.
  • It is the phase of the cell cycle where cell division takes place.
• The​ cell cycle in a human cell comprising of the Interphase and M phase lasts for a total time of 24 hours.

So the correct answer is option 1 (24 hours).