Biology Quiz: Cells In Human Body

Mitochondria is the energy-producing cytoplasmic organelle in a cell. It is responsible for generating adenosine triphosphate (ATP), which is the main source of energy for cellular activities. Mitochondria have their own DNA and can self-replicate. They are found in most eukaryotic cells and play a crucial role in cellular respiration. The other options, such as nucleus, Golgi apparatus, lysosomes, and cell wall, do not have the primary function of energy production.

The given statement, "denovo structure," is not a true statement about a cell. A cell is the basic unit of all living organisms, it does have its own DNA and RNA, it consists of cell organelles, and it can divide. However, "denovo structure" does not accurately describe a cell. A cell is not a structure that is created from scratch or built anew. Instead, it is a pre-existing structure that is essential for the functioning of living organisms.

Ribosomes are small cellular structures responsible for protein synthesis. They are present in both prokaryotic and eukaryotic cells. Prokaryotic cells, which include bacteria, have smaller ribosomes compared to eukaryotic cells. Eukaryotic cells, found in plants, animals, fungi, and protists, have larger and more complex ribosomes. Therefore, the statement "Ribosomes present in all prokaryotic and eukaryotic cells" is true.

The cell wall is a permeable structure because it allows certain substances to pass through it. This permeability is important for the cell to exchange nutrients, waste products, and other molecules with its surroundings. Without this permeability, the cell would not be able to function properly and maintain homeostasis. Therefore, the statement "Cell wall is a permeable structure" is true.

Autophagy is the process by which cells break down and recycle their own components, while suicide sac refers to the process of programmed cell death. Both of these terms are closely associated with lysosomes, which are organelles responsible for the degradation of cellular waste and the regulation of cell death. Therefore, the correct answer is lysosome.

Peroxysomes are organelles found in eukaryotic cells that are responsible for the breakdown of fatty acids and the detoxification of harmful substances, including hydrogen peroxide. They contain enzymes called catalases, which convert hydrogen peroxide into water and oxygen. Therefore, peroxysomes are the correct answer as they are directly involved in the formation of hydrogen peroxide. Glyoxysomes are involved in the conversion of fats into carbohydrates, lysosomes are responsible for the digestion of cellular waste and materials, and centrosomes are involved in cell division and the organization of the cytoskeleton.

In prokaryotic cells, protein synthesis occurs in the ribosomes. Ribosomes are small structures found in the cytoplasm of the cell and are responsible for assembling amino acids into proteins based on the instructions provided by the DNA. Unlike eukaryotic cells, prokaryotic cells do not have a nucleus, so the DNA is not confined within a membrane-bound organelle. Instead, the DNA is found in the cytoplasm in a region called the nucleoid. Therefore, the correct answer is ribosome.

Mitochondria are double membrane-bound cytoplasmic organelles that are inherited only from the mother. This is because during fertilization, the sperm contributes its genetic material to the nucleus of the egg, but the mitochondria from the sperm are typically destroyed. Therefore, the mitochondria in an individual's cells are derived solely from the mother. This unique inheritance pattern of mitochondria makes them a distinct organelle in terms of genetic transmission.

Chromosomes contain DNA and proteins. DNA is tightly coiled around proteins called histones to form a structure called chromatin. During cell division, the chromatin condenses further to form visible chromosomes. Chromosomes play a crucial role in carrying and transmitting genetic information from one generation to the next. Therefore, the presence of DNA and proteins in chromosomes is a well-established fact in biology.

Chromoplastids are plastids that contain pigments other than chlorophyll, which give them various colors. The most common colors of chromoplastids are red, yellow, and orange, which are responsible for the coloration of fruits and flowers. However, some chromoplastids can also have green pigments, although this is less common. Therefore, the correct answer is green, as it is one of the possible colors of chromoplastids.

Glyoxysomes are specialized organelles found in plants that play a crucial role in the conversion of fatty acids into sugars. This process, known as the glyoxylate cycle, allows plants to utilize stored lipids as an energy source during germination or periods of nutrient deprivation. By converting fatty acids into sugars, glyoxysomes provide the necessary building blocks for cellular respiration and energy production. This conversion is essential for the plant's survival and growth, making it an important function of glyoxysomes.

The correct answer is "Net work of protein fibers". The cytoskeleton is a network of protein fibers that provide structural support and shape to the cell. It also plays a role in cell movement and cell division. The cytoskeleton is composed of three main types of protein fibers: microfilaments, intermediate filaments, and microtubules. These fibers form a complex network throughout the cytoplasm, giving the cell its shape and allowing it to maintain its structural integrity.

The central plate-like compartments of the Dictyosome are called cisternae. These cisternae are flattened, membrane-bound sacs that make up the Golgi apparatus. They are involved in the processing, packaging, and sorting of proteins and lipids within the cell. The cisternae play a crucial role in the secretion of molecules and the formation of vesicles for transport to different parts of the cell or for secretion outside the cell.

Plasmodesmata are small channels that connect plant cells together, allowing for the transport of nutrients, water, and signaling molecules between cells. These channels are found in the cell wall, which is a rigid structure surrounding plant cells. Plasmodesmata are not present in the cytoplasm, nuclear membrane, or cell membrane.

The vacuole is a membrane-bound organelle found in the cells of plants and some protists. It is responsible for storing various substances, including water, ions, and nutrients. The main component of the vacuole is the cell sap, which is a solution of water, sugars, salts, and other organic molecules. The cell sap helps maintain the turgor pressure in plant cells, provides a storage space for nutrients and waste products, and plays a role in maintaining the pH balance within the cell. Therefore, the correct answer is "Cell sap."

Leucoplasts are a type of plastids that store food materials in plants. They are responsible for the synthesis and storage of starch, oils, and proteins. Unlike chloroplasts, which are responsible for photosynthesis, leucoplasts do not contain chlorophyll and are therefore colorless. They are commonly found in non-photosynthetic tissues such as roots, tubers, and seeds, where they play a crucial role in storing energy for the plant.

A chromosome with unequal arms, where one arm is too small and the other arm is too long, is classified as subtelocentric. In subtelocentric chromosomes, the centromere is located closer to one end, resulting in one short arm and one long arm. This type of chromosome structure can be observed in certain species and can have implications for genetic inheritance and gene expression.

Phospholipids are the major lipids of the cell membrane. They are composed of a hydrophilic head and hydrophobic tails, which allow them to form a bilayer structure in the cell membrane. This bilayer acts as a barrier, regulating the movement of substances in and out of the cell. Phospholipids also play a crucial role in cell signaling, as they can interact with proteins and other molecules to transmit signals across the membrane. Overall, phospholipids are essential for maintaining the integrity and functionality of the cell membrane.

Centromere is not a microtubule structure because it is a region of DNA found in the center of a chromosome. It plays a crucial role in the separation of chromosomes during cell division, but it is not a physical structure made up of microtubules like cilia, flagella, spindle fibers, or astral rays. Cilia and flagella are hair-like structures that extend from the surface of cells and are involved in cell movement. Spindle fibers are responsible for separating chromosomes during cell division, while astral rays are microtubules radiating from the centrosome.

Krabbe's disease is a lysosomal storage disease characterized by the loss of myelin, which is the protective covering of nerve fibers in the brain. This leads to the degeneration of the nervous system and results in mental retardation. Tay-Sachs disease is also a lysosomal storage disease but it primarily affects the central nervous system and does not specifically cause loss of myelin. Gaucher's disease primarily affects the liver and spleen and does not directly cause loss of myelin or mental retardation. Pneumonia is not a lysosomal storage disease and does not cause loss of myelin or mental retardation.