1.
Which part of the cell contains the genetic material and is often referred to as the "brain of the cell"?
Correct Answer
D. Nucleus
Explanation
The nucleus contains the cell’s genetic material, including DNA, and serves as the control center, regulating activities like growth, metabolism, and reproduction. Surrounded by the nuclear membrane, it houses chromatin and the nucleolus. While the nuclear membrane protects the nucleus, it does not store genetic material. Ribosomes synthesize proteins, the nucleolus produces ribosomes, and the endoplasmic reticulum supports protein and lipid synthesis. The nucleus’s critical role in coordinating cell functions earns it the title "brain of the cell."
2.
Which structure is present in plant cells but not in animal cells?
Correct Answer
A. Cell wall
Explanation
Plant cells have a rigid cell wall made of cellulose, which provides structural support and protection. This feature distinguishes them from animal cells, which lack a cell wall and instead rely on a flexible plasma membrane for regulating substance movement. Both plant and animal cells share structures like the nucleus, which stores genetic material, and the endoplasmic reticulum, which aids in protein and lipid synthesis. The cell wall also plays a vital role in maintaining the shape and preventing the plant cell from bursting under high water pressure.
3.
Which part of the cell assembles amino acids to form protein chains?
Correct Answer
A. Ribosomes
Explanation
Ribosomes are cellular structures responsible for assembling amino acids into protein chains, a process called translation. They either float freely in the cytoplasm or attach to the rough endoplasmic reticulum. Using messenger RNA (mRNA) as a template, ribosomes read genetic instructions from DNA to synthesize proteins. These proteins are then folded and modified for various functions. While the endoplasmic reticulum and Golgi apparatus process and transport proteins, ribosomes are the primary site of protein production. Centrioles, in contrast, are involved in cell division.
4.
Which part of the cell packages and transports substances within and outside the cell?
Correct Answer
B. Golgi apparatus
Explanation
The Golgi apparatus modifies, sorts, and packages proteins and lipids for delivery to their final destinations. This organelle receives materials from the endoplasmic reticulum, processes them, and encloses them in vesicles for transport. It plays a crucial role in the secretion of cellular products and the synthesis of membrane components. While mitochondria produce energy, and vacuoles store substances, the Golgi apparatus specifically handles packaging and transport functions essential for cellular activity.
5.
Which part of the cell digests old organelles and other unwanted materials?
Correct Answer
B. Lysosomes
Explanation
Lysosomes contain enzymes that break down and recycle cellular waste, including old organelles and macromolecules. These enzymes function in acidic environments to digest proteins, lipids, and carbohydrates, converting them into simpler molecules for reuse. This process, called autophagy, is critical for maintaining cellular health. In contrast, ribosomes synthesize proteins, vacuoles store materials, and the Golgi apparatus processes and packages substances. By managing waste disposal, lysosomes prevent the buildup of harmful substances in the cell.
6.
Which organelle produces the energy required for cellular functions?
Correct Answer
A. Mitochondria
Explanation
Mitochondria are the "powerhouses" of the cell, generating energy in the form of adenosine triphosphate (ATP) through cellular respiration. This process involves breaking down glucose and other nutrients in the presence of oxygen. ATP powers essential cellular processes, such as movement, growth, and repair. While ribosomes synthesize proteins, lysosomes digest cellular waste, the Golgi apparatus packages substances, and the nucleus controls cellular activities, mitochondria are uniquely responsible for energy production.
7.
Which organelle converts sunlight into glucose during photosynthesis?
Correct Answer
C. Chloroplasts
Explanation
Chloroplasts are specialized organelles in plant cells that perform photosynthesis, converting sunlight into chemical energy stored in glucose. They contain chlorophyll, a pigment that captures sunlight and facilitates the conversion of carbon dioxide and water into glucose and oxygen. This energy supports plant growth and sustains ecosystems. While mitochondria produce ATP, the nucleus controls cell functions, and vacuoles store substances, chloroplasts are exclusively responsible for harnessing solar energy to produce food.
8.
Which part of the cell is made up of a network of filaments that maintains its structure?
Correct Answer
C. Cytoskeleton
Explanation
The cytoskeleton is a network of protein filaments and tubules that provides structural support, maintaining the cell’s shape and stability. It also facilitates intracellular transport, cell division, and movement. Composed of microfilaments, intermediate filaments, and microtubules, the cytoskeleton works as a dynamic framework for organizing cell contents. While cytoplasm is the fluid matrix of the cell, the endoplasmic reticulum synthesizes proteins and lipids, and vacuoles primarily store materials, none perform the structural roles of the cytoskeleton.
9.
Which of these structures is NOT found in a prokaryotic cell?
Correct Answer
C. Nucleus
Explanation
Prokaryotic cells lack a nucleus, distinguishing them from eukaryotic cells. Instead, their genetic material is found in a nucleoid region within the cytoplasm. Other features like the cell membrane, which regulates entry and exit of substances, and the cell wall, providing structural support, are present in prokaryotes. Cytoplasm, a jelly-like substance, holds the cell’s internal components. The absence of a membrane-bound nucleus and organelles is a defining characteristic of prokaryotes, such as bacteria and archaea.
10.
Which part of the cell produces substances that do not contain proteins?
Correct Answer
A. Smooth endoplasmic reticulum
Explanation
The smooth endoplasmic reticulum (SER) synthesizes lipids, steroids, and hormones, none of which are protein-based substances. It also detoxifies drugs and harmful chemicals. Unlike the rough endoplasmic reticulum, which is covered with ribosomes and specializes in protein synthesis, the SER lacks ribosomes and focuses on lipid metabolism. Ribosomes and the nucleolus are directly involved in protein-related processes. By producing essential non-protein molecules, the SER plays a vital role in maintaining cellular homeostasis and metabolic activity.
11.
What is the jelly-like substance inside the cell that holds organelles in place?
Correct Answer
B. Cytoplasm
Explanation
Cytoplasm is a jelly-like substance found inside the cell that holds the organelles in place. It consists mainly of water, salts, and proteins, providing a medium for biochemical reactions. The cytoplasm facilitates the transport of materials across the cell and supports the structure of the organelles. It acts as a cushion, protecting the organelles from mechanical damage. Furthermore, the cytoplasm helps in the distribution of nutrients and waste, ensuring the cell's activities continue smoothly. It also aids in processes like glycolysis and protein synthesis, which occur within the cytoplasm.
12.
Which organelle stores water, nutrients, and waste products in plant cells?
Correct Answer
A. Vacuole
Explanation
The vacuole is responsible for storing water, nutrients, and waste products in plant cells. Vacuoles help maintain turgor pressure, which keeps plant cells rigid and maintains their structure. In addition to water, vacuoles store sugars, salts, proteins, and other important molecules. They also play a role in the breakdown of waste materials, similar to lysosomes in animal cells. The size of the vacuole can vary depending on the cell's needs. Vacuoles also contribute to the regulation of the cell's internal environment, allowing for optimal conditions for metabolic activities.
13.
What is the part of the cell where ribosomes are assembled?
Correct Answer
A. Nucleolus
Explanation
The nucleolus is the region within the nucleus responsible for producing ribosomes. It assembles ribosomal RNA (rRNA) and combines it with proteins to form the subunits of ribosomes. These ribosomal subunits are then transported out of the nucleus into the cytoplasm, where they combine to form functional ribosomes. This process is essential for protein synthesis because ribosomes are the sites where mRNA is translated into amino acid chains. The nucleolus plays a crucial role in maintaining cellular function by ensuring the efficient production of proteins, which are vital for cell survival and growth.
14.
Which cell structure regulates the movement of materials in and out of the cell?
Correct Answer
A. Plasma membrane
Explanation
The plasma membrane regulates the movement of materials in and out of the cell. It is made of a lipid bilayer with embedded proteins that control what enters or leaves the cell. The membrane's selective permeability allows the cell to maintain homeostasis by regulating ions, nutrients, and waste. The membrane uses various mechanisms such as diffusion, active transport, and endocytosis to control material exchange. It also has receptors that detect environmental changes, helping the cell respond to stimuli. This regulation is vital for maintaining the internal conditions necessary for cellular functions.
15.
What organelle contains enzymes that help digest worn-out cell parts and macromolecules?
Correct Answer
A. Lysosome
Explanation
Lysosomes contain enzymes that help digest worn-out cell parts and macromolecules. These enzymes are highly acidic and capable of breaking down complex molecules like proteins, lipids, and carbohydrates into simpler molecules that the cell can reuse. Lysosomes also play a critical role in autophagy, a process where the cell recycles its own damaged organelles. The acidic environment inside lysosomes enables them to perform these functions efficiently. Lysosomes are involved in cellular waste disposal and help maintain cellular health by removing potentially harmful substances, thus playing a vital role in the overall maintenance of the cell.