First Quarterly Examination In Biotechnology

The cell wall provides protection for plant and bacterial cells by providing structural support and preventing the cells from bursting or collapsing under pressure. It acts as a barrier against physical damage, pathogens, and environmental stresses. The cell wall is composed of tough and rigid materials such as cellulose in plants and peptidoglycan in bacteria, which give the cells their shape and strength.

The Cell Theory states that all living things are made of cells. This theory, proposed by Matthias Schleiden and Theodor Schwann in the 19th century, is one of the fundamental principles of biology. It states that cells are the basic building blocks of life and that all living organisms, whether plants, animals, or microorganisms, are composed of cells. This theory revolutionized the understanding of life and laid the foundation for the field of cell biology.

Bacteria have prokaryotic cells, which means they lack a nucleus and other membrane-bound organelles. Prokaryotic cells are simpler in structure compared to eukaryotic cells, which have a nucleus and other membrane-bound organelles. Bacteria are single-celled organisms that belong to the prokaryote domain. Their prokaryotic cells allow them to carry out essential functions such as reproduction, metabolism, and response to stimuli.

The nucleus is considered the "control center" of the cell because it contains the cell's genetic material, including DNA, which carries the instructions for the cell's functions and characteristics. The nucleus regulates the activities of the cell by controlling gene expression and directing protein synthesis. It also plays a crucial role in cell division and reproduction.

The correct order of the mitotic phases is prophase, metaphase, anaphase, telophase. During prophase, the chromatin condenses into visible chromosomes, the nuclear envelope breaks down, and the mitotic spindle begins to form. In metaphase, the chromosomes line up along the equator of the cell, attached to the spindle fibers. Anaphase is characterized by the separation of sister chromatids, which are pulled to opposite poles of the cell by the spindle fibers. Finally, during telophase, the chromosomes reach the poles of the cell, the nuclear envelope reforms, and the spindle fibers disassemble.

The correct answer is "Cell". A cell is considered the basic unit of life because it is the smallest structural and functional unit that can perform all the necessary processes for life, such as metabolism, growth, and reproduction. Cells are responsible for carrying out specific functions within an organism and can exist as independent entities or as part of a larger organism. They are the building blocks of all living organisms and are essential for the overall functioning and survival of an organism.

Eukaryotes are multicellular, meaning they are composed of multiple cells that are organized into tissues and organs. Prokaryotes, on the other hand, are unicellular, meaning they consist of a single cell that carries out all necessary functions. This fundamental difference in cellular organization is one of the key distinctions between eukaryotes and prokaryotes.

The cell membrane is a selectively permeable barrier that controls the movement of substances in and out of the cell. It regulates the entry and exit of molecules, ions, and nutrients, allowing essential substances to enter while preventing harmful substances from entering. This control is crucial for maintaining the cell's internal environment and ensuring its proper functioning.

Plant cells have chloroplasts, which are organelles responsible for photosynthesis. Chloroplasts contain chlorophyll, a pigment that captures sunlight and converts it into chemical energy. This process allows plants to produce glucose and oxygen, which are essential for their survival. Unlike animal cells, plant cells have the unique ability to produce their own food through photosynthesis, thanks to the presence of chloroplasts. These organelles are found in the cytoplasm of plant cells and are responsible for the green color of leaves and stems.

The concentration gradient refers to the difference in the concentration of particles between two areas. In diffusion, particles move from an area of higher concentration to an area of lower concentration. This movement occurs because particles tend to spread out and become evenly distributed. Therefore, the concentration gradient is the principal force driving movement in diffusion.

ATP (adenosine triphosphate) is the correct answer. ATP is a compound that stores and releases energy in cells through the process of cellular respiration. It is often referred to as the "energy currency" of the cell because it provides the necessary energy for various cellular activities. During cellular respiration, ATP is produced by breaking down glucose and other organic molecules, releasing energy that can be used by the cell for functions such as muscle contraction, active transport, and synthesis of molecules.

Humans have eukaryotic cells. Eukaryotic cells are characterized by having a true nucleus, which contains the genetic material, and membrane-bound organelles such as mitochondria and endoplasmic reticulum. These cells are more complex than prokaryotic cells, which lack a nucleus and organelles. In humans, eukaryotic cells make up all the tissues and organs in the body, including skin, muscles, and organs like the heart and brain.

Eukaryotes replicate through two processes: mitosis and meiosis. Mitosis is a type of cell division that results in two identical daughter cells with the same number of chromosomes as the parent cell. It is responsible for growth, development, and tissue repair. Meiosis, on the other hand, is a specialized type of cell division that produces gametes (eggs and sperm) with half the number of chromosomes as the parent cell. It is involved in sexual reproduction and genetic diversity.

Osmosis is a specific type of diffusion that involves the movement of water molecules across a selectively permeable membrane. It occurs when there is a difference in solute concentration between two solutions separated by the membrane. Water molecules move from an area of lower solute concentration to an area of higher solute concentration, in an attempt to equalize the concentration on both sides. Therefore, osmosis is the diffusion of ONLY water molecules, making the statement "True" correct.

Ribosomes are responsible for the synthesis of proteins within the cell. They are the site where protein production occurs, using the information encoded in the DNA. Ribosomes read the messenger RNA (mRNA) and link together amino acids to form a polypeptide chain, which then folds into a functional protein. Therefore, the correct answer is "make proteins".

The Golgi complex is responsible for storing and packaging chemicals within the cell. It receives proteins and lipids from the endoplasmic reticulum and modifies them, sorting them into vesicles for transport to their final destination. This organelle plays a crucial role in the secretion of proteins and the formation of lysosomes.

Prophase is the correct answer because it is the first phase of mitosis. During prophase, the chromosomes condense and become visible, the nuclear membrane breaks down, and the spindle fibers start to form. This phase prepares the cell for division by organizing and separating the genetic material. Anaphase, metaphase, and interphase are all subsequent phases of mitosis and do not occur before prophase.

When there is a movement of water but no net movement, it indicates that the concentration of solutes inside and outside the cell is equal. This means that the tonicity is isotonic, as there is no net movement of water across the cell membrane. In an isotonic solution, the concentration of solutes is the same inside and outside the cell, resulting in no change in cell volume.

The mitochondrion is known as the "powerhouse" of the cell because it is responsible for producing energy in the form of ATP through a process called cellular respiration. This energy is vital for the cell to carry out its various functions and activities. The other options mentioned in the question, such as controlling the movement of materials or being someone's best friend, do not accurately describe the function of the mitochondrion.

Plants have eukaryotic cells because they are multicellular organisms and eukaryotic cells are found in all multicellular organisms. Eukaryotic cells are characterized by having a nucleus and membrane-bound organelles, such as mitochondria and chloroplasts, which are essential for various cellular functions. This is in contrast to prokaryotic cells, which lack a nucleus and membrane-bound organelles. Therefore, plants have eukaryotic cells.

Facilitated diffusion differs from simple diffusion because it requires transport proteins. In facilitated diffusion, molecules move across the cell membrane with the help of specific transport proteins, while in simple diffusion, molecules move directly through the cell membrane without the need for any proteins. The presence of transport proteins allows facilitated diffusion to occur at a faster rate and enables the selective movement of specific molecules.

In eukaryotic cells, chromosomes are found in the nucleus. The nucleus is the membrane-bound organelle that houses the cell's genetic material, including the chromosomes. The chromosomes contain the DNA molecules that carry the genetic information necessary for the cell's functioning and inheritance. The nucleus provides a protected environment for the chromosomes, allowing for proper regulation of gene expression and DNA replication. Therefore, the correct answer is nucleus.

The vacuole is the correct answer because it is a storage structure within the cell. Vacuoles are membrane-bound organelles that store water, nutrients, and waste materials. They play a crucial role in maintaining the cell's turgor pressure, regulating osmotic balance, and storing various substances such as ions, sugars, and proteins. Vacuoles are particularly prominent in plant cells, where they can occupy a large portion of the cell's volume.

Mitosis is the process of cell division where the nucleus of a cell divides, producing two new identical nuclei that are identical to the original nucleus. This division allows for growth and replaces worn out or damaged cells. Therefore, all of the statements mentioned are correct and describe different aspects of mitosis.

During mitosis, the spindle plays a crucial role in separating the chromosomes. The spindle is a structure made up of microtubules that extend from opposite poles of the cell and attach to the chromosomes at their centromeres. As the spindle fibers contract, they pull the sister chromatids apart, ensuring that each daughter cell receives the correct number of chromosomes. This process is essential for maintaining the genetic integrity of the daughter cells and ensuring proper cell division.

Cells are shaped the way they are because of their specific functions. Different cells have different shapes that allow them to carry out their specialized tasks more efficiently. For example, nerve cells are long and thin, which enables them to transmit electrical signals over long distances. Red blood cells are biconcave in shape, providing a larger surface area for oxygen exchange. Therefore, the shape of cells is determined by their function and helps them perform their specific roles effectively.

Diffusion is the process that moves any material from high concentrations to low concentrations. It occurs due to the random motion of particles, where they move from an area of high concentration to an area of low concentration until equilibrium is reached. This process is passive and does not require energy expenditure. Active transport, endocytosis, and osmosis involve the movement of materials, but they do not specifically refer to the movement from high concentrations to low concentrations.

This statement is false because not all living things have multiple cells. There are single-celled organisms, such as bacteria and protists, that only have one cell. Therefore, it is incorrect to say that all living things have multiple cells.

Animal cells do not have chloroplasts because chloroplasts are organelles found only in plant cells. Chloroplasts are responsible for photosynthesis, the process by which plants convert sunlight into energy. Animal cells obtain energy through other mechanisms such as cellular respiration, which occurs in the mitochondria. The absence of chloroplasts in animal cells is one of the distinguishing features between plant and animal cells.

During metaphase of mitosis, sister chromatids line up along the center of the dividing cell. This is facilitated by the formation of the mitotic spindle, which attaches to the centromeres of the sister chromatids and aligns them at the metaphase plate. This alignment ensures that each daughter cell receives an equal number of chromosomes during cell division.

Passive transport is the correct answer because it is a type of transport that does not require energy. In passive transport, molecules move from an area of high concentration to an area of low concentration, down their concentration gradient. This can occur through processes such as diffusion or facilitated diffusion. In the context of the question, since the movement of starch molecules from left to right is happening without the input of energy, it is likely occurring through passive transport.

Phagocytosis is the process by which cells engulf and ingest large particles or whole cells. It involves the formation of a phagosome, a membrane-bound vesicle that contains the ingested material. This transport mechanism allows the cell to bring in whole cells, such as bacteria or other foreign particles, for various purposes such as immune response or nutrient acquisition. Pinocytosis, on the other hand, involves the uptake of small dissolved molecules or fluids, facilitated transport involves the movement of specific molecules across the cell membrane with the help of carrier proteins, and primary active transport involves the use of ATP to move molecules against their concentration gradient.

Water moves via osmosis from an area with a high concentration of water to one of lower concentration. Osmosis is the movement of water molecules across a selectively permeable membrane from an area of higher water concentration to an area of lower water concentration. This process occurs in order to equalize the concentration of solutes on both sides of the membrane.

During anaphase, the sister chromatids of each chromosome separate and move towards the opposite poles of the spindle. This is facilitated by the shortening of the microtubules of the spindle fibers, which pull the chromatids apart. As a result, each pole of the spindle receives a complete set of chromosomes, ensuring that each daughter cell will have the correct number of chromosomes. This process is essential for proper cell division and the formation of genetically identical daughter cells.

Prokaryotic cells are small cells that lack a nucleus. Unlike eukaryotic cells, which have a well-defined nucleus that houses the genetic material, prokaryotic cells have their DNA floating freely in the cytoplasm. These cells are typically found in bacteria and archaea. They are characterized by their simplicity and lack of membrane-bound organelles. Prokaryotic cells are able to carry out essential cellular functions, such as protein synthesis and energy production, despite their small size and lack of a nucleus.

Centrioles are small dark bodies found outside the nucleus that play a crucial role in cell division. They are responsible for organizing the microtubules that form the spindle fibers during mitosis and meiosis. The spindle fibers help in the separation of chromosomes and the distribution of genetic material to the daughter cells. Therefore, centrioles are essential for the proper division and distribution of genetic material during cell division.

The cell cycle is a series of events that occur in a cell, leading to its division and the production of two daughter cells. The two main stages of the cell cycle are mitosis and interphase. Mitosis is the stage where the cell's nucleus divides into two identical nuclei, while interphase is the stage where the cell grows, carries out its normal functions, and prepares for division. Therefore, the correct answer is mitosis and interphase.

When a cell shrinks, it means that water is leaving the cell and the concentration of solutes inside the cell is higher than the concentration outside the cell. This situation is known as hypertonicity, where the extracellular solution has a lower solute concentration compared to the intracellular solution. As a result, water moves out of the cell, causing it to shrink.

Cytolysis refers to the bursting of a cell due to an imbalance in the concentration of solutes inside and outside the cell. In a hypotonic solution, the concentration of solutes outside the cell is lower than inside the cell. This creates a concentration gradient that causes water to move into the cell, leading to an influx of water and potential swelling. If the influx of water exceeds the cell's capacity to expand, it can result in the bursting or cytolysis of the cell. Therefore, hypo is the correct answer as it describes the condition in which cytolysis may occur.

Interphase refers to the stage of the cell cycle when a cell carries out its metabolic processes. This is the period between cell divisions where the cell grows, replicates its DNA, and prepares for division. It is characterized by high metabolic activity and the cell performs its normal functions during this stage. This is in contrast to the stages of mitosis, which are specifically involved in cell division.

ATP (adenosine triphosphate) is a molecule that stores and releases energy in cells. It consists of three phosphate groups attached to adenosine. When a bond is broken between two phosphate groups in ATP, energy is released. This is because the bond between phosphate groups is relatively unstable and contains a large amount of potential energy. Breaking this bond allows the energy to be used for cellular processes such as muscle contraction, active transport, and synthesis of molecules. Therefore, the correct answer is that ATP releases energy when a bond is broken between two phosphate groups.

Proteins can be found on the surface of the plasma membrane or embedded within the membrane structure. They play a crucial role in various cellular processes such as transport, signaling, and cell adhesion. Some proteins span the entire width of the membrane, forming channels or transporters, while others are attached to the inner or outer surface of the membrane. The presence of proteins in the plasma membrane allows for its dynamic nature and functionality.

Osmosis is a passive process that occurs without the need for energy input. It involves the movement of water molecules across a semi-permeable membrane from an area of higher concentration to an area of lower concentration. This movement occurs in order to equalize the concentration of solute on both sides of the membrane. Therefore, the correct characteristics of osmosis are that it moves molecules from high concentration to low concentration and it does not require energy input.

Adenosine diphosphate (ADP) is a molecule that consists of adenosine, a ribose sugar, and two phosphate groups. The correct answer is "three phosphate groups" because ADP only has two phosphate groups.

Centrioles are responsible for producing spindle fibers during cell division. Spindle fibers play a crucial role in separating the chromosomes and ensuring proper distribution of genetic material to the daughter cells. The centrioles are located near the nucleus and organize the formation of the spindle apparatus, which aids in the movement of chromosomes during mitosis or meiosis. Therefore, the correct answer is centrioles.

In a hypertonic solution, there is a higher concentration of solutes outside the cell compared to inside the cell. This creates a concentration gradient, causing water to move out of the cell through osmosis. As a result, the net movement of water is out of the cell.

Interphase is the correct answer because it is the longest phase of the cell cycle where the cell spends the majority of its time. During interphase, the cell grows, replicates its DNA, and prepares for cell division. It is a critical phase for the cell to carry out its normal functions and ensure that it is ready for the next stages of the cell cycle, including mitosis and cytokinesis.

During interphase, the cell undergoes various processes, including DNA replication. This is the phase where the cell prepares for cell division by duplicating its genetic material. DNA replication is essential for the accurate transmission of genetic information to daughter cells. It ensures that each new cell receives a complete set of genetic instructions. Therefore, interphase is the correct answer because it is the phase where DNA replication occurs.

During the S phase of the cell cycle, DNA in a cell is copied through a process called DNA replication. This is the phase where the cell's DNA is synthesized, resulting in two identical copies of the genetic material. The S phase is a crucial step in cell division, as it ensures that each daughter cell receives a complete set of DNA.

Pinocytosis is the process in which liquids from the surrounding area are taken into the cell. It involves the formation of small vesicles that engulf the liquid and bring it into the cell. This process is a form of endocytosis, where materials are brought into the cell through the cell membrane. In contrast, exocytosis is the process by which materials are released from the cell, while passive transport refers to the movement of substances across the cell membrane without the use of energy. Phagocytosis, on the other hand, is the process of engulfing and digesting solid particles.