Fundamental Unit of Life: Important Questions

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Very Short Answer Questions  (1 Mark Questions)

Ques. Inside the cell, where are proteins synthesized?

Ans. Ribosomes are the sites within the cell where protein is synthesized.

Ques. What is a hypotonic solution?

Ans. A hypotonic solution is one with a solute concentration lower than that of cell sap.

Ques. What is the name of the plastid that stores starch, oils, and protein granules?

Ans. Amyloplast-Leucoplasts for starch, elaioplast for oil, and aleuroplast for protein.

Ques. Identify the cell organelle that is known as the cell's powerhouse. Give the reason.

Ans. Mitochondrion. It is the primary site of ATP production, which is used as a source of energy for various cell functions.

Ques. What is active transport?

Ans. Active transport refers to the movement of molecules across a membrane in cells against a concentration gradient using ATP units.

Ques. What is endocytosis?

Ans. Endocytosis is the ingestion or engulfment of food and other material through the folding of the plasma membrane, as seen in amoebas.

Ques. What is Microscope?

Ans. Microscope is an optical instrument consisting of a lens or combination of lenses which renders minute objects distinctly visible.

Ques. Why is a light microscope referred to as a compound microscope?

Ans. A compound microscope is a light microscope that has two or more lens systems.

Ques. Define plasmolysis.

Ans. It can be defined as the shrinkage of cytoplasm due to loss of water when kept in a hypertonic medium.

Ques. Define diffusion.

Ans. The movement of molecules from a region of higher concentration to a region of lower concentration is called diffusion.

Read More: Difference Between Hypotonic and Hypertonic Solution

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Short Answer Questions (2 Marks Questions)

Ques.What is the relevance of the cell being referred to as the structural and functional unit of life?

Ans. Since all living organisms are made up of cells, the cell is the basic building unit of a living organism, and all of a living organism's activities are the sum of activities carried out by its cells, the cell is referred to as the structural and functional unit of life.

Ques. Why are lysosomes referred to as suicide bags?

Ans. Lysosomes are intracellular organelles that contain hydrolytic (digestive) enzymes. When a cell is damaged, its lysosomes may rupture, allowing enzymes to digest the cell. As a result, lysosomes have earned the moniker "suicide bags."

Ques. What are cytosol and cytoskeleton?

Ans. The semifluid part of the cell cytoplasm that is embedded between cell organelles is known as cytosol. The cytoskeleton is a network of protein fibers found in the cell that serves as a framework for the organelles.

Ques. What would happen to a cell's life if the Golgi apparatus was not present?

Ans. The Golgi apparatus is responsible for the preservation, modification, and packaging of products in particles. All types of material storage, modification, packaging, and dispatch within and outside the cell would be impossible if the cell did not have a Golgi apparatus.

Ques. Based on the size and number of chromosomes, distinguish between eukaryotic and prokaryotic cells.

Ans. A prokaryotic cell's genetic material is equivalent to a small histone-free chromosome and is commonly referred to as a prochromosome. A eukaryotic cell has two or more histone-supported larger chromosomes.

Ques. Describe the structure of mitochondria using the membrane covering as a reference.

Ans. Mitochondria are colorless rod or sausage-shaped organelles of aerobic eukaryotes with a double membrane covering. The outer membrane is permeable. The inner membrane has been folded. The folds are known as cristae. They contain ATP-producing elementary particles. The matrix contains Krebs cycle enzymes.

Ques. Why is endocytosis only found in animals?

Ans. Endocytosis requires a flexible outermost membrane, similar to an animal's plasma membrane. However, in plant cells, the cell wall is the rigid outermost membrane. As a result, endocytosis occurs exclusively in animals and not in plants.

Read More: Differences between Endocytosis and Exocytosis

Ques. Which cell organelle controls the majority of the cell's activities? 

Ans. The nucleus, also known as the cell's brain, controls the majority of the cell's activities because it contains DNA (Deoxyribonucleic acid), which contains all of the cell's information.

Ques. How do you calculate a microscope's magnification?

Ans. A microscope's magnification is calculated by multiplying the powers of the eyepiece and objective lenses. M = P1xP2, where Pi is the power of the eyepiece and P2 is the power of the objective.

Ques. If chloroplasts did not exist, there would be no plant life. Justify.

Ans. Chloroplasts contain the pigment chlorophyll, which is responsible for plant food preparation via the photosynthesis process. As a result, if chloroplasts did not exist, there would have been no plant life.

Read More: Photosynthesis and Chemiosmotic Hypothesis

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Long Answer Questions (3 Marks Questions)

Ques. Give an example of the concept of division of labor in multicellular organisms.

Ans. The taking on of different functions of the system/body by different specialized components in a coordinated fashion so that the whole benefits without any part being overworked is referred to as division of labor. It improves efficiency. In multicellular organisms such as humans, there are numerous organs, tissues, and cells that perform various functions, such as muscle contraction and movement, nerve impulse transmission, oxygen transport by RBCs, germ protection by white blood corpuscles, gamete formation by germ cells, blood pumping by heart, waste extraction by kidneys, and so on.

Ques. What happens if the plasma membrane ruptures or breaks down? Where are the lipids and proteins synthesized that are used to make up the cell membrane?

Ans. The rupture or breakdown of a cell's plasma membrane indicates that the cell has been injured, and in this case, the damaged cell's lysosomes may burst, causing the digestive enzymes contained within those lysosomes to eat their own cell. As an outcome, the cell will die.

Endoplasmic reticulum is classified into two types:

1. The smooth endoplasmic reticulum (SER) is in charge of generating the lipids that comprise the cell membrane.
2. Ribosomes are housed in the rough endoplasmic reticulum (RER), which is in charge of producing the proteins that make up the cell membrane.

Read More: Difference Between Smooth and Rough Endoplasmic Reticulum

Ques. What is osmosis? Where does an amoeba get its food?

Ans. Amoeba feeds on water-floating planktonic bacteria. It grows artificial feet, or pseudopodia, to encircle the meal and then traps it in a sac-like structure called the food vacuole, where food digestion takes place.

Osmosis is the passage of water (solvent) through a semipermeable membrane from a region of high water concentration to a region of low water concentration. It can occur only in a liquid medium; it cannot occur in solids or gases. Water is absorbed from the earth by plant roots, for example.

Ques. How do substances such as CO₂ and water enter and exit the cell? Discuss.

Ans. CO₂ moves by diffusion – These cellular wastes accumulate in high concentrations within the cell, whereas CO₂ concentrations in the surrounding environment are relatively lower. Because of the difference in concentration levels inside and outside the cell, CO₂ diffuses from a region of higher concentration (within the cell) to a region of lower concentration.

Osmosis allows water to pass through the cell membrane. It moves through a selectively permeable membrane from a higher concentration region to a lower concentration region until equilibrium is reached.

Ques. What exactly are asters and spindle fibers? Give reason why animal cells do not have a cell wall.

Ans. Asters are two star-shaped structures that radiate fibers from the centrosome. They aid in the location of the spindle and cause cytoplasm cleavage. Spindle fibers are formed during cell division from microtubules. They separate the chromosomes and bring them to the poles. These are wider in the center and narrower at the ends.

Animals do not have rigid walls because they are incompatible with the way animals move and grow. The flaccid cell membrane allows animal cells to move freely and form different tissues, which plants do not have.

Read More: Difference Between Cytosol and Cytoplasm

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Very Long Answer Questions (5 Marks Questions)

Ques. Compare the ways in which plant cells are different from animal cells.

Ans. The table illustrates the differences between plant cells and animal cells.

Plant Cell and Animal Cell

Ques. Experiment with osmosis as follows:

In order to make potato cups, take four peeled potato halves and scoop out each one. A boiled potato should be used to make one of these potato cups. Place each potato cup in a water-filled trough. Now, (a) Keep the cup A void

1. Fill cup B with one teaspoon of sugar.
2. Fill cup C with one teaspoon of salt.
3. Fill the boiled potato cup D with one teaspoon of sugar.

Keep these for two hours. Then look at the four potato cups and answer the following questions:

(a) Explain why water collects in the hollowed out sections of B and C.

(b) What is the significance of Potato A in this experiment?

(c) Describe why water does not collect in the hollowed-out sections of A and D.

Ans. (a) When we add one teaspoon of sugar to cup B and one teaspoon of salt to cup C, we create a hypertonic solution within, allowing water from the outside to enter through osmosis and accumulate in the hollowed areas of cups B and C.

(b) You'll need Potato A to observe osmosis.

(c) Osmosis cannot occur and water does not collect because there is no solution (liquid medium) in the hollowed-out portions of A and D.

Ques. State the difference between a prokaryotic cell and a eukaryotic cell?

Ans.  Given below are the differences between prokaryotic and eukaryotic cells: 

• Prokaryotic Cell

1. Size: Generally large (5-100 μm)
2. Well defined nuclear region girdled by a nuclear membrane.
3. There are more than one chromosome.
4. Membrane-bound cell organelles present.

• Eukaryotic Cell

1. Size: Generally small (1-10 μm)
2. μm = 10-6m
3. Not a well defined nuclear region as the nuclear membrane is absent and is referred to as the nucleoid.
4. There is a single chromosome.
5. Membrane-bound cell organelles absent.

Ques. A. Do all of our body's cells have the same shape, size, and structure? What are their similarities?

1. What is the significance of the term "selectively permeable membrane" for the plasma membrane?

Ans. (A) No, they do not have the same shape or size. Similarities,

• The covering of the plasma membrane.
• The presence of a centrally placed nucleus.
• Cytoplasm and various cell organelles, Examples include the Golgi apparatus, lysosomes, mitochondria, ribosomes, and endoplasmic reticulum. 
• The metabolic pathways

Cells differentiate in order to perform different functions. They also come in a variety of shapes and sizes, such as nerve cells, bone cells, fat cells, ovums, sperm, blood cells, and muscle fibers.

(B) The plasma membrane is a unique structure. It is composed of lipids and proteins that selectively allow some molecules into the cell while preventing others from exiting, making it selectively permeable.

Read More: Eukaryotic Nucleus

Ques.

1. Do you agree with the statement "A cell is a building unit of an organism?" If so, please explain why.
2. If you're given some vegetables to cook, you'll usually season them with salt. Vegetables release water after being salted. Why?
3. What is the relationship between chromatin, chromatids, and chromosomes?

Ans. (A) An organism is composed of various organ systems such as the digestive system, nervous system, and so on. These organ systems, in turn, are composed of various organs, which are composed of tissues. Tissues are a group of cells that perform the same function. uAs a result, a cell is the building unit of an organism. Cell → tissue → organ → organ system → organism

(B) When salt is added, a hypotonic medium is formed, which means that the concentration of salt molecules is greater outside the vegetables than inside. As a result of osmosis, water from the vegetables escapes.

(C) Chromatin is a thin thread-like structure made up of DNA (deoxyribonucleic acid) and proteins that combine to form a rod-like chromatid. A chromosome is formed when two similar chromatids join together at a centromere.

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