Biology II 1st Quarter Final Exam

The nucleotide sequence of the other DNA strand can be determined by pairing each nucleotide with its complementary base. In DNA, adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G). Therefore, the complementary sequence to CCGTACT would be GGCACTG.

Cytoplasm is the correct answer because it refers to the jellylike substance that is contained inside the cell membrane. It is a semi-fluid substance that fills the cell and contains various organelles, such as mitochondria and ribosomes. Cytoplasm plays a crucial role in supporting cellular activities and providing a medium for chemical reactions to occur.

Selective permeability refers to the property of a membrane or barrier that allows only certain molecules or ions to pass through while blocking others. In this case, the correct answer "some molecules pass" accurately describes this property. It implies that the membrane selectively allows certain molecules to cross while preventing others from doing so.

Organelles are specialized structures that perform specific functions within a cell. They are found in eukaryotic cells, which are cells that have a nucleus and membrane-bound organelles. Prokaryotes, on the other hand, do not have membrane-bound organelles. Nuclei, on the other hand, are the central organelles in eukaryotic cells that contain the cell's genetic material. Therefore, the correct answer is organelles.

The invention that played the biggest role in the discovery of cells by early scientists is the microscope. The microscope allowed scientists to magnify and observe objects at a much smaller scale, enabling them to discover and study cells for the first time. Without the microscope, it would have been impossible for scientists to observe the intricate details and structures of cells, leading to a significant breakthrough in the field of biology.

Active transport is a process that requires the cell to expend energy in order to move molecules or ions across the cell membrane against their concentration gradient. This energy is typically derived from ATP, the main energy currency of cells. In contrast, passive transport relies on concentration gradients or diffusion to move molecules or ions across the cell membrane without the need for energy input. Therefore, the correct answer is "energy from the cell."

Facilitated diffusion is a type of cellular transport that uses transport proteins to move molecules across the cell membrane. It involves the passive movement of molecules from an area of higher concentration to an area of lower concentration, with the help of specific carrier proteins. On the other hand, active transport also uses transport proteins but requires energy to move molecules against their concentration gradient, from an area of lower concentration to an area of higher concentration. Both facilitated diffusion and active transport are essential for maintaining homeostasis and allowing the cell to selectively transport molecules in and out.

Passive transport is a type of cellular transport that does not require any energy from the cell. It occurs along the concentration gradient, where molecules move from an area of higher concentration to an area of lower concentration. Unlike active transport, which requires energy in the form of ATP, passive transport can occur through simple diffusion or facilitated diffusion. In simple diffusion, molecules move directly through the cell membrane, while facilitated diffusion involves the use of transport proteins to facilitate the movement of specific molecules.

Endocytosis is a process in which cells take in substances from the external environment by engulfing them with their cell membrane. This process is facilitated by the formation of vesicles, which are small membrane-bound sacs that transport the engulfed substances into the cell. Therefore, both vesicles and vesicle are correct answers as they are organelles involved in the process of endocytosis.

Mitochondria are organelles that supply energy to the cell through the process of cellular respiration. They are often referred to as the "powerhouses" of the cell because they produce adenosine triphosphate (ATP), which is the main source of energy for cellular activities. Mitochondria have their own DNA and can replicate independently within the cell. They are present in most eukaryotic cells and are particularly abundant in cells that require a lot of energy, such as muscle cells.

Plant cells have cell walls and chloroplasts, while animal cells do not. Cell walls provide structural support and protection for plant cells, while chloroplasts are responsible for photosynthesis, allowing plant cells to produce their own food. Animal cells do not have cell walls and rely on other mechanisms for support and protection. Additionally, animal cells do not have chloroplasts as they obtain energy through other means, such as consuming other organisms or organic matter.

Facilitated diffusion is the movement of molecules down a concentration gradient through transport proteins in the cell membrane. This process does not require energy expenditure and is a type of selective transport. Osmosis, on the other hand, is the movement of water molecules across a semipermeable membrane, while energy expenditure refers to active transport where molecules move against the concentration gradient. Therefore, facilitated diffusion is the correct answer in this case.

Watson and Crick combined the work of other scientists with their own research to discover that two strands of DNA join together to form a double helix. This means that the DNA strands twist around each other in a spiral staircase-like structure. The double helix shape of DNA is important for its stability and ability to store and transmit genetic information.

Lysosomes are organelles that contain enzymes responsible for breaking down damaged cell parts. They act as the recycling centers of the cell, breaking down waste materials, old organelles, and foreign substances. This process, known as autophagy, helps maintain cellular health and remove any damaged or unnecessary components. Lysosomes play a crucial role in maintaining the overall functionality and cleanliness of the cell.

The correct answer is "all existing cells are produced by other living cells." This statement aligns with the principle of cell theory, which states that cells arise from pre-existing cells. This concept was proposed by Rudolf Virchow in 1855 and is supported by numerous observations and experiments. It contradicts the idea of spontaneous generation, which suggests that cells can arise spontaneously from non-living matter. Instead, cell theory emphasizes the continuity of life and the importance of cell division in the growth, development, and reproduction of organisms.

A prokaryotic cell does not have a nucleus. Prokaryotic cells are simple and lack a membrane-bound nucleus. Instead, their DNA is found in a region called the nucleoid, which is not enclosed by a membrane. In contrast, eukaryotic cells have a true nucleus that houses their DNA, which is separated from the cytoplasm by a nuclear membrane.

The cytoskeleton is a network of proteins that provides structural support and shape to a cell. It is responsible for maintaining the cell's shape, organizing the internal components, and facilitating cell movement. The cytoskeleton is made up of three main components: microfilaments, intermediate filaments, and microtubules. These protein filaments work together to give the cell its shape and allow it to carry out its functions.

Osmosis is the term for the diffusion of water across a semipermeable membrane. In osmosis, 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 of the membrane. This process is important for maintaining the balance of water and solutes in cells and tissues.

Rough ER refers to the endoplasmic reticulum that is studded with ribosomes. Ribosomes are responsible for protein synthesis, and when they are attached to the surface of the ER, it gives it a rough appearance. This rough ER is involved in the production, folding, and modification of proteins before they are transported to their final destinations. The ribosomes on the rough ER play a crucial role in protein synthesis, making the phrase "studded with ribosomes" the best description for rough ER.

The correct answer is chloroplasts and cell wall. Chloroplasts are unique to plant cells and are responsible for photosynthesis, where sunlight is converted into energy. They contain chlorophyll, which gives plants their green color. The cell wall is another unique feature of plant cells. It provides support and protection to the cell, allowing plants to maintain their shape and withstand external pressures. Unlike animal cells, plant cells have a rigid cell wall made of cellulose.

A phospholipid is composed of a polar head and a nonpolar tail. The polar head contains a phosphate group, which is hydrophilic (water-loving) and interacts with water molecules. The nonpolar tail is made up of fatty acid chains, which are hydrophobic (water-repelling) and do not interact with water. This unique structure allows phospholipids to form the lipid bilayer of cell membranes, with the polar heads facing the watery environment inside and outside the cell, and the nonpolar tails facing each other in the interior of the bilayer.

Water moves into a cell when the solution surrounding the cell is hypotonic. This is because in a hypotonic solution, the concentration of solutes outside the cell is lower than inside the cell. As a result, water molecules move from an area of lower solute concentration (outside the cell) to an area of higher solute concentration (inside the cell) through osmosis. This causes the cell to swell and possibly burst if the influx of water is too high.

The nucleus is the storehouse for most of a cell's genetic information. It contains the cell's DNA, which carries the instructions for the cell's growth, development, and functioning. The DNA is organized into structures called chromosomes, which are located within the nucleus. The nucleus also plays a crucial role in controlling the cell's activities and regulating gene expression. Therefore, the nucleus is responsible for storing and protecting the cell's genetic information.

Mitosis is the stage of the cell cycle where the nucleus and its contents divide. During mitosis, the duplicated DNA in the nucleus is separated into two identical sets and distributed into two new daughter cells. This process ensures that each daughter cell receives the same genetic information as the parent cell. Therefore, mitosis is the correct answer for the stage of the cell cycle where the nucleus and its contents divide.

Ribosomes can be found in the cytoplasm and on the surface of the endoplasmic reticulum. They are responsible for protein synthesis and can be found in both prokaryotic and eukaryotic cells. They play a vital role in translating the genetic information from DNA into functional proteins. Ribosomes are composed of ribosomal RNA (rRNA) and proteins, and they can be free-floating in the cytoplasm or attached to the endoplasmic reticulum, forming the rough endoplasmic reticulum.

A vesicle is a membrane-bound sac that is used to transport substances into and out of cells. It acts as a small transport vehicle within the cell, allowing molecules to be moved from one location to another. Vesicles are involved in various cellular processes, including the uptake of nutrients, secretion of molecules, and the recycling of cellular components. They play a crucial role in maintaining the overall functioning and homeostasis of the cell.

During the process of mitosis, the parent cell divides into two identical daughter cells. Mitosis involves the replication and distribution of genetic material, resulting in the formation of two cells that are genetically identical to each other and to the parent cell. Cytokinesis, on the other hand, is the division of the cytoplasm and other cellular components between the two daughter cells. Therefore, the correct answer is daughter cells.

Active transport is the process that uses proteins to move molecules against a concentration gradient. This means that it moves molecules from an area of lower concentration to an area of higher concentration. Unlike passive transport, which relies on the natural movement of molecules from an area of higher concentration to an area of lower concentration, active transport requires the use of energy in the form of ATP. Endocytosis and phagocytosis are types of active transport, but they specifically refer to the process of engulfing large particles or fluids into the cell.

The correct answer is DNA because the ratio of nitrogen to phosphorus in Avery's extracts was consistent with that of DNA. This suggests that the extracts contained DNA rather than enzymes, protein, or bacteria. The nitrogen-phosphorus ratio is a characteristic feature of DNA, as DNA contains nitrogenous bases and phosphorus in its backbone.

The four types of nucleotides that make up DNA are named for their nitrogen-containing bases. Nitrogen-containing bases are the molecules that form the "rungs" of the DNA ladder, pairing up with each other to form the double helix structure. There are four types of nitrogen-containing bases: adenine (A), thymine (T), cytosine (C), and guanine (G). These bases are crucial for the genetic code and determine the specific sequence of DNA. Therefore, it is accurate to say that the nucleotides are named after their nitrogen-containing bases.

Erwin Chargaff concluded that in DNA, the amount of adenine (A) is equal to the amount of thymine (T), and the amount of cytosine (C) is equal to the amount of guanine (G). This is known as Chargaff's rule and it indicates that these bases pair up in a specific way in the DNA double helix.

Cytokinesis refers to the process of dividing the cytoplasm of a cell. This occurs after the nucleus has divided during cell division. The cytoplasm divides to form two separate cells, each with its own nucleus. Therefore, the phrase "division of the cytoplasm" best describes cytokinesis.

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Bacteriophages are viruses that specifically infect bacteria. Hershey and Chase chose to use bacteriophages in their experiments because they wanted to study the genetic material of viruses. Bacteriophages are composed mainly of DNA and protein, making them ideal for studying the transfer of genetic material. They do not contain complex cellular structures like other organisms, which makes it easier to isolate and study their genetic material. Therefore, the statement "contain little more than DNA and protein" accurately explains why Hershey and Chase chose to use bacteriophages in their experiments.

During prophase, the DNA molecules in the cell start to condense and coil tightly, forming structures called chromosomes. This process allows the DNA to become more compact and organized, making it easier to separate and distribute evenly during cell division. Therefore, the correct answer is prophase.