Cell: The Unit of Life

Correct Answer: C

Although each membranous organelle has its own distinct structure and function, many of them work together in a coordinated manner, especially in processes like protein and lipid synthesis, modification, and transport. Due to this functional coordination, they are collectively referred to as the endomembrane system.

Correct Answer: B

The endomembrane system includes the endoplasmic reticulum (ER), Golgi complex, lysosomes, and vacuoles. These organelles work together in a coordinated way for the synthesis, modification, packaging, and transport of cellular materials.

Correct Answer: A

The mitochondria, chloroplast and peroxisomes are not part of the endomembrane system because their functions are not coordinated with the ER, Golgi complex, lysosomes and vacuoles.

Correct Answer: B

1. ER is like tiny pipes inside the cell.
2. It is a network of tubes present in the cytoplasm.
3. It was seen clearly using an electron microscope.
4. It is connected to the nuclear membrane.
5. It has two types: Rough ER (with ribosomes) and Smooth ER (without ribosomes).
6. Rough ER makes proteins and Smooth ER makes lipids.
7. It also helps in protein folding, detoxification, and calcium storage.

Correct Answer: B

1. ER divides the cell into different spaces.
2. It forms a network inside the cytoplasm.
3. This creates two separate regions in the cell.
4. One region is inside the ER called the luminal space.
5. The other region is outside the ER in the cytoplasm.
6. These are called luminal and extra luminal compartments.
7. This separation helps in proper cellular functions and biochemical processes.
8. The luminal space provides a controlled environment for protein folding and modification.
9. Many enzymes function specifically within the ER lumen.
10. The extra luminal space allows interaction with other organelles and cytosolic processes.
11. This compartmentalization increases efficiency of cellular activities.
12. It prevents mixing of different biochemical reactions.
13. Helps in transport of materials through vesicles between compartments.
14. Maintains internal organization of the cell.
15. Important for advanced cellular regulation and signaling processes.

Correct Answer: B

1. The outer surface of ER can have small particles attached to it.
2. These particles are called ribosomes.
3. When ribosomes are present, it is called rough endoplasmic reticulum (RER).
4. Ribosomes give a rough appearance to the ER surface.
5. They are the sites of protein synthesis in the cell.
6. Proteins made here are transported inside the ER.
7. These proteins are later modified and sent to other parts of the cell.
8. Ribosomes can be free in cytoplasm or attached to ER.
9. Attached ribosomes mainly make proteins for secretion or membranes.
10. This helps in efficient production and transport of proteins.

Correct Answer: B

1. ER with small particles on its surface is called rough ER.
2. These small particles are ribosomes.
3. Ribosomes make proteins in the cell.
4. Because of ribosomes, ER looks rough under microscope.
5. Rough ER is mainly found near the nucleus.
6. It helps in synthesis and transport of proteins.
7. These proteins are sent to Golgi complex for further processing.
8. Rough ER is important for making membrane and secretory proteins.
9. It plays a key role in cell growth and repair.
10. Helps maintain proper functioning of the cell.

Correct Answer: B

1. ER without ribosomes looks smooth.
2. This type is called smooth endoplasmic reticulum (SER).
3. It does not have ribosomes on its surface.
4. Because of this, it appears smooth under microscope.
5. SER mainly helps in lipid (fat) synthesis.
6. It is important for making phospholipids and steroids.
7. SER also helps in detoxification of drugs and harmful substances.
8. It plays a role in carbohydrate metabolism.
9. In muscle cells, it helps in calcium storage and release.
10. SER is essential for maintaining cell metabolism and internal balance.

Correct Answer: B

1. Rough ER is found in cells that make many proteins.
2. It has ribosomes attached on its surface.
3. Ribosomes help in protein synthesis.
4. These proteins are needed for secretion outside the cell.
5. Cells like plasma cells and gland cells have more RER.
6. Proteins made in RER enter its lumen for processing.
7. They are then transported to the Golgi complex.
8. RER helps in proper folding and modification of proteins.
9. It ensures proteins are correctly made before transport.
10. Thus, RER is important in protein synthesis and secretion.

Correct Answer: B

1. Rough ER forms a large network inside the cell.
2. It spreads widely throughout the cytoplasm.
3. It is connected directly to the nuclear membrane.
4. Specifically, it is continuous with the outer membrane of the nucleus.
5. This connection helps in easy transport of materials.
6. Proteins made in RER can quickly move from nucleus region.
7. It helps in coordination between nucleus and ER.
8. This continuity maintains structural organization of the cell.
9. It improves efficiency of protein synthesis and transport.
10. Thus, ER and nuclear membrane function together smoothly.

Correct Answer: B

1. Smooth ER does not have ribosomes on its surface.
2. It appears smooth under the microscope.
3. It is mainly responsible for lipid synthesis.
4. It produces phospholipids and steroids.
5. These lipids are important for cell membrane formation.
6. SER also helps in making cholesterol and hormones.
7. It plays a role in detoxification of drugs and toxins.
8. It helps in carbohydrate metabolism.
9. In muscle cells, it stores and releases calcium ions.
10. Thus, SER is essential for lipid production and cell function.

Correct Answer: B

1. Smooth ER is involved in lipid synthesis.
2. It does not contain ribosomes on its surface.
3. In animal cells, it produces special lipid-based substances.
4. These are called steroidal hormones.
5. Examples include hormones like testosterone and estrogen.
6. These hormones are important for body regulation.
7. SER helps in their formation from cholesterol.
8. It also plays a role in detoxification of harmful substances.
9. This process is important in liver and endocrine cells.
10. Thus, SER is essential for synthesis of lipid-like steroidal hormones.

Correct Answer: B

1. Scientists study cells to understand their structure.
2. One scientist observed special structures inside cells.
3. These structures were seen near the nucleus.
4. They appeared as densely stained reticular (network-like) bodies.
5. This observation was made using a microscope.
6. The scientist who discovered this was Camillo Golgi.
7. He made this discovery in the year 1898.
8. Later, these structures were named Golgi bodies or Golgi apparatus.
9. They play an important role in packaging and transport of materials.
10. This discovery was a key step in cell biology.

Correct Answer: B

1. A scientist observed special structures inside the cell.
2. These structures were seen near the nucleus.
3. They appeared as a network-like arrangement.
4. The discovery was made by Camillo Golgi.
5. To honor him, the structures were named after him.
6. They are called Golgi bodies or Golgi apparatus.
7. These structures help in packaging cellular materials.
8. They modify and transport proteins and lipids.
9. They play an important role in secretion in cells.
10. Thus, they were named Golgi bodies after him.

Correct Answer: B

1. Golgi bodies are made up of many flattened sacs.
2. These sacs are called cisternae.
3. They are arranged one above the other like stacks.
4. Each sac is disc-shaped in structure.
5. They form a network near the nucleus.
6. The size of each cisterna is very small.
7. Their diameter ranges from 0.5µm to 1.0µm.
8. These structures help in packaging cell materials.
9. They modify proteins and lipids before transport.
10. Thus, Golgi bodies consist of flat sacs of 0.5µm to 1.0µm diameter.

Correct Answer: B

1. Golgi bodies are made up of flattened sacs called cisternae.
2. These sacs are arranged one above the other.
3. They form a neat stack-like structure.
4. Each sac lies in the same direction.
5. This arrangement is called parallel stacking.
6. It helps in efficient processing of materials.
7. Proteins and lipids move through these stacks.
8. Each layer performs specific modifications.
9. This organized structure improves cell function.
10. Thus, Golgi bodies are stacked parallel to each other.

Correct Answer: B

1. Golgi complex is made up of flattened sacs.
2. These sacs are called cisternae.
3. They are arranged in stacked layers.
4. The number of these sacs is not fixed.
5. Different cells may have different numbers of cisternae.
6. Cells with high activity may have more cisternae.
7. Each cisterna performs specific functions.
8. They help in modification and packaging of substances.
9. This variation helps meet the needs of the cell.
10. Thus, varied number of cisternae are present in a Golgi complex.

Correct Answer: B

1. Golgi apparatus is located near the nucleus.
2. It is made up of stacked cisternae arranged concentrically.
3. These stacks have two distinct faces.
4. The convex side is called the cis face.
5. The cis face is also known as the forming face.
6. It receives materials from the endoplasmic reticulum.
7. The concave side is called the trans face.
8. The trans face is known as the maturing face.
9. It sends modified materials to other parts of the cell.
10. This polarity helps in proper processing and transport.

Correct Answer: B

1. Golgi apparatus has two sides called cis and trans faces.
2. The cis face receives materials from the ER.
3. The trans face sends processed materials out of the cell.
4. Both faces have different structures and functions.
5. The cis face is convex, while the trans face is concave.
6. Even though they are different, they are connected through cisternae.
7. Materials move from cis face to trans face step by step.
8. Each region modifies substances in a specific way.
9. This connection helps in smooth transport and processing.
10. Thus, they are entirely different but interconnected.

Correct Answer: B

1. Golgi apparatus is an important cell organelle.
2. It receives materials like proteins and lipids from ER.
3. These materials are modified and sorted in the Golgi.
4. Its main function is packaging of these materials.
5. Packaged materials are enclosed in vesicles.
6. Some are sent to different parts inside the cell.
7. These are called intra-cellular targets.
8. Some materials are transported outside the cell.
9. This process is called secretion.
10. Thus, Golgi apparatus packages materials for internal use or secretion.

Correct Answer: B

1. Materials are first formed in the endoplasmic reticulum.
2. These materials are packed into small vesicles.
3. Vesicles move towards the Golgi apparatus.
4. They fuse with the cis face of the Golgi.
5. The cis face is the receiving side.
6. Materials then pass through Golgi cisternae.
7. They undergo modification and sorting.
8. Finally, they reach the trans face.
9. The trans face is the maturing and dispatching side.
10. From here, materials are sent to their final destinations.

Correct Answer: B

1. Endoplasmic reticulum (ER) produces proteins and lipids.
2. These materials are packed into vesicles.
3. Vesicles move from ER to Golgi apparatus.
4. They fuse with the cis face of the Golgi.
5. Golgi modifies and sorts these materials.
6. Then it packages them for transport.
7. This continuous transfer requires close connection.
8. Hence Golgi remains near the ER.
9. This helps in efficient transport and processing.
10. Thus, Golgi apparatus is closely associated with ER.

Correct Answer: B

1. Ribosomes on rough ER make proteins.
2. These proteins enter the ER lumen.
3. They are packed into vesicles.
4. Vesicles carry them to the Golgi apparatus.
5. They enter through the cis face.
6. Inside the Golgi, proteins move through cisternae.
7. They are modified and processed step by step.
8. Modifications include folding and addition of molecules.
9. Finally, they reach the trans face.
10. From the trans face, proteins are released to their destinations.

Correct Answer: B

1. Golgi apparatus modifies proteins and lipids received from ER.
2. It adds carbohydrate groups to proteins.
3. This forms glycoproteins.
4. It also adds carbohydrates to lipids.
5. This forms glycolipids.
6. These molecules are important for cell membrane structure.
7. They help in cell recognition and communication.
8. They are essential for secretion and transport.
9. Golgi ensures proper processing of these molecules.
10. Thus, Golgi apparatus is the main site for formation of glycoproteins and glycolipids.

Correct Answer: B

1. Lysosomes are small sac-like structures in the cell.
2. They are surrounded by a single membrane.
3. Hence, they are called membrane bound vesicles.
4. They are formed from the Golgi apparatus.
5. Golgi packages enzymes into these vesicles.
6. Lysosomes contain digestive enzymes.
7. These enzymes break down waste materials.
8. They help in cleaning the cell.
9. They are also called the 'suicide bags' of the cell.
10. Thus, lysosomes are membrane bound vesicular structures.

Correct Answer: B

1. Lysosomes contain many digestive enzymes.
2. These enzymes break down different substances.
3. They are called hydrolytic enzymes or hydrolases.
4. Examples include lipases, proteases and carbohydrases.
5. Lipases break fats, proteases break proteins, carbohydrases break carbohydrates.
6. These enzymes work best in acidic conditions.
7. Lysosomes maintain an acidic internal pH.
8. This helps enzymes function efficiently.
9. They digest waste materials and old cell parts.
10. Thus, lysosomes are rich in hydrolytic enzymes active at acidic pH.

Correct Answer: C

1. Lysosomes contain powerful digestive enzymes.
2. These enzymes can break many types of biomolecules.
3. They digest carbohydrates using carbohydrases.
4. They break proteins using proteases.
5. They digest lipids using lipases.
6. They also break nucleic acids using nucleases.
7. This helps in removal of waste materials.
8. Old and damaged cell parts are also digested.
9. This process is important for cell cleaning and recycling.
10. Thus, these enzymes can digest carbohydrates, proteins, lipids and nucleic acids.

Correct Answer: B

1. Vacuoles are spaces present inside the cell.
2. They are found in the cytoplasm.
3. Each vacuole is surrounded by a membrane.
4. Hence, they are called membrane-bound structures.
5. The membrane is called tonoplast.
6. Vacuoles store water, nutrients and wastes.
7. They help in maintaining cell pressure (turgor).
8. In plant cells, vacuoles are large and prominent.
9. In animal cells, they are smaller or temporary.
10. Thus, vacuoles are membrane-bound spaces in the cytoplasm.

Correct Answer: B

1. Vacuoles act as storage spaces inside the cell.
2. They contain mainly water and cell sap.
3. Cell sap includes dissolved substances.
4. Vacuoles also store waste materials.
5. These are called excretory products.
6. Many stored substances are not useful for the cell.
7. They help in isolating harmful materials.
8. This protects the rest of the cell.
9. Vacuoles also maintain internal balance of the cell.
10. Thus, vacuoles contain water, sap, excretory products and other unwanted materials.

Correct Answer: B

1. Vacuole is a storage space inside the cell.
2. It is surrounded by a membrane.
3. This membrane is single layered.
4. The membrane has a special name.
5. It is called tonoplast.
6. Tonoplast controls movement of substances in and out.
7. It helps maintain cell balance.
8. It also supports storage functions of vacuole.
9. It is especially important in plant cells.
10. Thus, vacuole is bound by a membrane called tonoplast.

Correct Answer: C

1. Vacuoles are large storage spaces in plant cells.
2. They contain water, cell sap and other materials.
3. In plant cells, vacuoles are very large.
4. They push the cytoplasm towards the cell wall.
5. This helps maintain cell shape and rigidity.
6. Vacuoles store nutrients and waste products.
7. They also help in maintaining turgor pressure.
8. Because of their large size, they occupy most of the cell.
9. They can take up to 90 per cent of cell volume.
10. Thus, vacuoles occupy about 90 per cent of plant cell volume.

Correct Answer: B

1. Tonoplast is the membrane surrounding the vacuole.
2. It controls movement of substances into the vacuole.
3. In plants, it actively transports ions and materials.
4. This transport occurs against concentration gradients.
5. It requires energy for this process.
6. As a result, substances accumulate inside the vacuole.
7. Their concentration becomes higher than in cytoplasm.
8. This helps in storage of ions and nutrients.
9. It also maintains osmotic balance and turgor pressure.
10. Thus, tonoplast enables active transport into the vacuole.

Correct Answer: B

1. Amoeba is a single-celled organism.
2. It lives in freshwater environments.
3. Water continuously enters the cell by osmosis.
4. The contractile vacuole collects excess water.
5. It periodically expels this water outside.
6. This process is called osmoregulation.
7. It helps maintain proper water balance in the cell.
8. The vacuole also removes waste substances.
9. This function is called excretion.
10. Thus, contractile vacuole is important for osmoregulation and excretion.

Correct Answer: B

1. Some unicellular organisms take in food from their surroundings.
2. They engulf food particles using their cell membrane.
3. This process is called endocytosis.
4. The engulfed food is enclosed inside a sac.
5. This sac is called a food vacuole.
6. Food vacuoles contain the ingested material.
7. Digestive enzymes act on this food.
8. Nutrients are released and absorbed by the cell.
9. This process is common in protists like Amoeba.
10. Thus, food vacuoles are formed by engulfing food particles.