1.
Which organelle protects and supports the cell, controls everything that enters and leaves the cell, and recognizes chemical signals?
Correct Answer
D. Plasma membrane
Explanation
The plasma membrane is the correct answer because it is responsible for protecting and supporting the cell, controlling what enters and leaves the cell through selective permeability, and recognizing chemical signals through receptors embedded in the membrane. It acts as a barrier between the cell and its external environment, allowing it to maintain homeostasis and communicate with other cells.
2.
Which organelle is known as the 'power plant of the cell'?
Correct Answer
B. Mitochondria
Explanation
Mitochondria are often referred to as the "power plants" of the cell because they are responsible for generating most of the cell's supply of adenosine triphosphate (ATP), the energy currency of the cell. This energy is essential for supporting various functions within the cell, such as muscle contraction, nerve impulse propagation, and chemical synthesis. Mitochondria have their own DNA and are unique in their ability to convert energy from food into usable energy very efficiently, which is why they play such a crucial role in energy production within cells.
3.
Yeast is an example of
Correct Answer
B. Eukaryotic cell
Explanation
Yeast is an example of a eukaryotic cell because it possesses a nucleus and other membrane-bound organelles. Eukaryotic cells are typically found in organisms such as plants, animals, fungi, and protists. They are characterized by their complex internal structure and ability to perform various specialized functions. Yeast, a type of fungus, is a single-celled organism that exhibits eukaryotic characteristics, making it an example of a eukaryotic cell.
4.
Which organelle helps make and transport proteins and lipids?
Correct Answer
A. Endoplasmic recticulum
Explanation
The endoplasmic reticulum (ER) is an organelle that helps make and transport proteins and lipids. It is a network of membranous tubules and sacs located in the cytoplasm of eukaryotic cells. The ER plays a crucial role in protein synthesis, folding, and modification. It also participates in lipid synthesis and detoxification of drugs and toxins. The ER is connected to the nuclear envelope and is divided into two regions: rough ER, which is studded with ribosomes and involved in protein synthesis, and smooth ER, which lacks ribosomes and is involved in lipid metabolism and detoxification.
5.
Which organelle contains digestive enzymes?
Correct Answer
D. Lysosomes
Explanation
Lysosomes are organelles that contain digestive enzymes. These enzymes help break down waste materials, cellular debris, and foreign substances within the cell. Lysosomes play a crucial role in cellular digestion and recycling of cellular components. They are responsible for maintaining the overall health and functioning of the cell by removing unwanted materials and recycling them for energy or building new molecules. Therefore, the correct answer is lysosomes.
6.
Which organelles are involved in cell division and are found in the cytoplasm near the nucleus?
Correct Answer
A. Centrioles
Explanation
Centrioles are organelles that are involved in cell division and are found in the cytoplasm near the nucleus. They play a crucial role in organizing the microtubules that make up the cell's cytoskeleton and are necessary for the formation of the spindle fibers during cell division. Centrioles are also involved in the movement of chromosomes during cell division, ensuring that each daughter cell receives the correct number of chromosomes. Therefore, the presence of centrioles near the nucleus is important for their proper functioning in cell division.
7.
The genetic characters are determined by which organelle?
Correct Answer
D. Nucleus
Explanation
The genetic characters are determined by the nucleus. The nucleus contains the DNA, which carries the genetic information that determines an organism's characteristics. The DNA is transcribed into RNA, which is then translated into proteins that play a role in determining the organism's traits. The mitochondrion, Golgi bodies, and ribosomes all have important functions in the cell, but they do not directly determine the genetic characters of an organism.
8.
Which organelles are known as the 'protein factories of the cell'?
Correct Answer
D. Ribosomes
Explanation
Ribosomes are the protein factories of the cell. They are responsible for protein synthesis, where they translate the genetic information from the DNA into proteins. Ribosomes can be found in the cytoplasm of the cell, as well as on the rough endoplasmic reticulum. They play a crucial role in the production of proteins, which are essential for various cellular processes and functions. Mitochondria are responsible for energy production, while the cytoplasm is the fluid-filled region of the cell where various cellular activities occur. Therefore, the correct answer is Ribosomes.
9.
Which is a rigid layer that surrounds the plasma membrane of a plant cell?
Correct Answer
B. Cell wall
Explanation
The cell wall is a rigid layer that surrounds the plasma membrane of a plant cell. It provides structural support and protection to the cell, helping to maintain its shape and prevent it from bursting under pressure. The cell wall is composed of cellulose, a complex carbohydrate that gives it its rigidity. Unlike animal cells, which do not have a cell wall, plant cells rely on this structure for support and to withstand environmental stresses.
10.
What is the liquid in the nucleus that surrounds the nucleolus and chromatins?
Correct Answer
C. Nucleoplasm
Explanation
Nucleoplasm is the correct answer because it is a liquid found in the nucleus of a cell. It surrounds the nucleolus and chromatins, providing a medium for various cellular activities. The nucleoplasm contains various molecules, such as enzymes, proteins, and nucleotides, which are essential for gene expression and DNA replication. It also helps in maintaining the structural integrity of the nucleus and provides a suitable environment for the storage and transport of genetic material.
11.
Which of the following is absent in plant cells?
Correct Answer
C. Centrioles
Explanation
Centrioles are absent in plant cells. Centrioles are small cylindrical structures found in animal cells that play a role in cell division. They are involved in the formation of spindle fibers during cell division, aiding in the separation of chromosomes. Plant cells, on the other hand, do not have centrioles. Instead, they rely on other structures, such as the microtubule organizing centers, to perform similar functions during cell division. Therefore, the absence of centrioles is a characteristic feature of plant cells.
12.
Which of the following maintains the intracellular pressure in animal cell?
Correct Answer
B. Vacuoles
Explanation
Vacuoles maintain the intracellular pressure in animal cells. Vacuoles are membrane-bound organelles that store various substances such as water, ions, and nutrients. They help regulate the osmotic balance within the cell by controlling the movement of water and solutes. By storing and releasing water, vacuoles can regulate the internal pressure of the cell, maintaining its shape and stability. Additionally, vacuoles can also play a role in cellular waste management and detoxification.
13.
Which one of the following is not a plastid?
Correct Answer
A. Cell wall
Explanation
Plastids are a group of organelles found in plant cells that are involved in various functions such as photosynthesis, storage, and pigment synthesis. Chloroplasts and chromoplasts are examples of plastids. However, the cell wall is not a plastid. The cell wall is a rigid structure made of cellulose that surrounds the cell membrane and provides support and protection to the cell. Unlike plastids, the cell wall does not contain any specialized pigments or participate in photosynthesis. Therefore, the correct answer is "Cell wall."
14.
Which is absent in animal cell?
Correct Answer
D. All above
Explanation
Animal cells do not have a cell wall, chloroplasts, or chromoplasts. The cell wall is a rigid layer found in plants, fungi, and bacteria that helps maintain shape and provides structural support. Chloroplasts and chromoplasts are types of plastids found in plant cells. Chloroplasts are involved in photosynthesis, converting sunlight into energy, while chromoplasts store pigments that color some fruits and flowers. Animal cells lack these structures, relying on different mechanisms for support, energy production, and storage.
15.
Which of the following is responsible for the formation of new cells?
Correct Answer
D. Centrosomes
Explanation
Centrosomes are responsible for the formation of new cells. Centrosomes play a crucial role in cell division, specifically in the formation of the mitotic spindle during cell division. The mitotic spindle helps to separate the replicated chromosomes into two daughter cells, ensuring that each new cell receives a complete set of genetic material. Therefore, centrosomes are essential for the formation of new cells through cell division.
16.
Example of a single-celled organism is
Correct Answer
C. Amoeba
Explanation
Amoeba is an example of a single-celled organism. It is a microscopic, unicellular organism that belongs to the group of protozoans. Amoebas are characterized by their ability to constantly change their shape, as they do not have a fixed body structure. They move by using pseudopods, which are temporary projections of their cytoplasm. Amoebas are found in various freshwater and marine environments, as well as in soil. They are capable of both asexual and sexual reproduction, and they obtain their nutrition by engulfing and digesting small particles of food.
17.
Organisms made up of huge amount of cells(like humans) are known as
Correct Answer
A. Multicellular
Explanation
Organisms made up of a large number of cells, like humans, are known as multicellular organisms. Multicellular means having or consisting of many cells. This characteristic allows for specialization and complexity within the organism. Different groups of cells can take on different functions, such as forming tissues and organs. This division of labor among cells allows multicellular organisms to perform complex tasks and adapt to diverse environments. In contrast, unicellular organisms are made up of a single cell, and epithelial and epidermal refer to types of tissues found in multicellular organisms.
18.
Which statement about unicellular organisms is true?
Correct Answer
A. Unicellular organisms carry out many of the same activities as multicellular organisms.
Explanation
Unicellular organisms, despite being made up of only one cell, carry out many of the same essential life processes as multicellular organisms. These include respiration, digestion, reproduction, and response to environmental changes. Their single cell must perform all necessary functions to sustain life, demonstrating a remarkable level of complexity and efficiency. This ability contrasts with the other statements, which are inaccurate; unicellular organisms vary greatly in structure, are generally microscopic in size, and can thrive in diverse environments, not just warm dry ones.
19.
Which of the following is the best definition of cell?
Correct Answer
D. Cell is both a structural and functional unit of living organisms.
Explanation
The best definition of a cell is that it is both a structural and functional unit of all living organisms. This definition captures the essential role that cells play: they are the basic building blocks that make up the structure of all organisms, and they carry out the necessary functions to sustain life. Cells process nutrients, convert those nutrients into energy, and perform specialized functions. They also reproduce, which allows for growth and repair in organisms. This definition underscores the fundamental importance of cells in biology, making it more comprehensive than the other options presented.