Bio 1 Midterm Exam

DNA and RNA are two types of nucleic acids. Nucleic acids are large biomolecules that store and transmit genetic information in living organisms. DNA (deoxyribonucleic acid) is responsible for storing and transmitting genetic information, while RNA (ribonucleic acid) plays a key role in protein synthesis. Both DNA and RNA are composed of nucleotides, which are the building blocks of nucleic acids. Therefore, the correct answer is nucleic acids.

Protein polymers are made of a series of amino acids. Amino acids are the building blocks of proteins and are linked together through peptide bonds to form long chains called polypeptides. These polypeptides then fold and interact with each other to form functional proteins. Monosaccharides are the building blocks of carbohydrates, histones are proteins that help in DNA packaging, and DNA strands are nucleic acids that carry genetic information. Therefore, the correct answer is amino acids.

The nucleus is the storehouse for a cell's genetic information. It contains the cell's DNA, which carries the instructions for making proteins and performing other cellular functions. The DNA is organized into structures called chromosomes, which are found inside the nucleus. The nucleus is surrounded by a nuclear membrane, which helps protect the DNA and regulate the movement of molecules in and out of the nucleus. Overall, the nucleus plays a crucial role in maintaining and transmitting genetic information in a cell.

Transport proteins are responsible for the movement of molecules across cell membranes. They facilitate the transport of molecules in both passive and active transport processes. Passive transport refers to the movement of molecules across a membrane without the need for energy, while active transport requires energy to move molecules against their concentration gradient. Therefore, transport proteins are involved in both passive transport, such as diffusion, and active transport, such as vesicle transport.

The major principle upon which cell theory is based is that all organisms are made of cells. This means that all living things, whether they are plants, animals, or microorganisms, are composed of cells. This principle was first proposed by scientists Schleiden and Schwann in the 19th century and has since been supported by numerous observations and experiments. It is a fundamental concept in biology and provides the basis for understanding the structure and function of living organisms.

Proteins are one of the four main types of carbon-based molecules in organisms. They are composed of amino acids and play a crucial role in various biological processes. Proteins are involved in structural support, enzymatic reactions, transportation, and communication within cells. They are essential for the growth, repair, and maintenance of tissues and organs in living organisms.

Hydrogen bonds give water many properties that are important to living things. These bonds occur between the hydrogen atoms of one water molecule and the oxygen atoms of nearby water molecules. They give water a high boiling point, allowing it to exist as a liquid at room temperature. Hydrogen bonds also give water a high heat capacity, meaning it can absorb and release large amounts of heat without changing temperature significantly. Additionally, these bonds contribute to water's cohesive and adhesive properties, allowing it to stick to surfaces and flow easily through narrow channels, which is crucial for many biological processes.

The cytoskeleton is a network of proteins that provides structural support to the cell and helps maintain its shape. It is responsible for various cellular processes such as cell division, cell movement, and the transport of materials within the cell. The cytoskeleton is composed of three main types of proteins: microfilaments, intermediate filaments, and microtubules. These proteins form a complex network that gives the cell its shape and allows it to carry out its functions effectively.

Rough ER is described as "studded with ribosomes" because it is a type of endoplasmic reticulum that contains ribosomes attached to its surface. These ribosomes are responsible for protein synthesis. The rough ER plays a crucial role in the production, processing, and transport of proteins within the cell. It is involved in the modification and folding of proteins before they are transported to other organelles or secreted outside the cell. Therefore, the phrase "studded with ribosomes" accurately describes the rough ER's structure and function.

Mitochondria are the organelles that supply energy to the cell. 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 processes. Mitochondria have their own DNA and can replicate independently within the cell. They are involved in cellular respiration, where they break down glucose and convert it into ATP through a series of chemical reactions. This process provides energy for various cellular activities, such as metabolism and movement.

Osmosis is the correct answer because it refers to the process of water molecules moving from an area of higher concentration to an area of lower concentration through a semipermeable membrane. This movement occurs in order to equalize the concentration of solutes on both sides of the membrane. The other options, equilibrium, transport, and isotonic, do not specifically describe the diffusion of water across a semipermeable membrane.

Selective permeability refers to the property of a membrane or barrier that allows only certain molecules or ions to pass through while restricting the passage of others. In this case, the correct answer is "some molecules pass," indicating that the membrane selectively allows the passage of specific molecules while blocking others.

Cytokinesis is the process that divides the cytoplasm. During cytokinesis, the cytoplasm of a cell is divided into two daughter cells, each containing a complete set of genetic material. This process occurs after the nuclear division (mitosis or meiosis) and is essential for the proper distribution of genetic material and organelles to each daughter cell. Anaphase, S phase, and telophase are all different stages of the cell cycle but do not directly involve the division of the cytoplasm.

The carrying capacity of a population in an ecosystem refers to the average maximum number of individuals that the ecosystem can support. It represents the point at which the available resources in the ecosystem, such as food, water, and space, can no longer sustain an increase in population size. It is not related to the rate at which individuals die off, the amount of animals in the biome, or how an ecosystem can carry a population to another ecosystem.

Fats, oils, and cholesterol are all types of lipids. Lipids are a group of organic compounds that are insoluble in water but soluble in organic solvents. They play important roles in the body, including providing energy, insulating and protecting organs, and serving as structural components of cell membranes. Hormones, cell membranes, and fatty acids are not broad enough categories to encompass all three substances mentioned in the question.

A pH of 12 would be considered a strong base. The pH scale measures the acidity or alkalinity of a solution, with values below 7 being acidic, 7 being neutral, and values above 7 being alkaline. A pH of 12 is significantly higher than 7, indicating a high concentration of hydroxide ions. This high concentration of hydroxide ions makes the solution highly alkaline or basic.

During anaphase in mitosis, sister chromatids separate and are pulled towards opposite poles of the cell. This is made possible by the contraction of the spindle fibers attached to the centromeres of the sister chromatids. Once separated, each chromatid is considered an individual chromosome. Anaphase is a crucial stage in mitosis as it ensures that each daughter cell receives the correct number of chromosomes.

Scientists use observations and data to form and test hypotheses. Hypotheses are proposed explanations or predictions that can be tested through further observations and experiments. They are essential in the scientific method as they help guide the research process and provide a framework for making predictions and drawing conclusions based on evidence. By testing hypotheses, scientists can gather evidence to support or reject them, leading to a better understanding of the natural world.

The Golgi apparatus is responsible for processing and delivering proteins within the cell. It receives proteins from the endoplasmic reticulum and modifies them by adding sugars and lipids. It then packages these modified proteins into vesicles for transport to their final destinations within the cell or for secretion outside of the cell. This process ensures that proteins are properly sorted and directed to where they are needed, allowing for proper cellular function.

Controlled variables are the factors in an experiment that are intentionally kept constant or unchanged. These variables are carefully controlled to ensure that any observed changes or effects can be attributed to the independent variable being tested. By keeping these variables constant, researchers can minimize the influence of outside factors and increase the reliability and validity of their results.

An atom is the smallest basic unit of matter that retains the properties of an element. It consists of a nucleus, which contains protons and neutrons, and electrons that orbit around the nucleus. Atoms combine to form molecules, compounds, and cells, but they are the fundamental building blocks of all matter.

An ion is formed when an atom gains or loses electrons. When an atom gains electrons, it becomes a negatively charged ion called an anion. When an atom loses electrons, it becomes a positively charged ion called a cation. Ions are formed through the process of ionization, which occurs when atoms interact with other atoms or molecules and transfer electrons. Ions play a crucial role in chemical reactions and are often involved in the formation of compounds and molecules.

Lysosomes contain enzymes that break down old cell parts. Lysosomes are membrane-bound organelles that are responsible for the digestion and recycling of cellular waste materials, including old cell parts. They contain a variety of enzymes, such as proteases, lipases, and nucleases, that break down proteins, lipids, and nucleic acids, respectively. This process, known as autophagy, allows the cell to remove and recycle damaged or unnecessary components, maintaining cellular health and homeostasis.

The correct answer is Active transport. Active transport is a type of cellular transport that requires energy to move molecules or ions across a cell membrane against their concentration gradient. In the diagram, it is likely showing a process where molecules are being actively transported from an area of low concentration to an area of high concentration. This requires the use of energy, such as ATP, to drive the transport process.

The structure labeled F in Fig. 3.3 is responsible for holding water. This suggests that it is likely a specialized structure that is designed to store water, such as a vacuole or a water-holding tissue. The other options, such as conducting photosynthesis, housing genetic material, or producing energy molecules, do not align with the function of holding water. Therefore, the correct answer is hold water.

The best explanation for why new communities were able to replace older communities is that the abiotic characteristics of the habitat changed. This means that the physical and non-living factors of the environment, such as temperature, sunlight, and soil composition, underwent significant alterations over the 200-year period. These changes likely created new conditions that favored the establishment and survival of different communities of organisms, allowing them to replace the older communities that were not well-suited to the new habitat.

When graphing experimental results, the dependent variables should be placed onto the y axis. The dependent variable is the variable that is being measured or observed in the experiment, and it is typically the variable that is expected to change in response to the manipulation of the independent variable. By placing the dependent variable on the y axis, we can visually represent how it changes in relation to the independent variable, which is typically placed on the x axis.

Chloroplasts are the organelles found only in plant cells. They are responsible for photosynthesis, the process by which plants convert sunlight into energy. Chloroplasts contain chlorophyll, a pigment that captures light energy, and other necessary components for photosynthesis. This organelle is not present in animal cells, making it unique to plant cells.

A catalyst is a substance that increases the rate of a chemical reaction by lowering the activation energy required for the reaction to occur. It achieves this by providing an alternative reaction pathway with a lower energy barrier. This allows more reactant molecules to overcome the energy barrier and form products, thus increasing the rate of the reaction. Therefore, a catalyst decreases the activation energy needed for a chemical reaction.

The structures labeled B would be made of protein. This is because proteins are macromolecules made up of amino acids and play a crucial role in the structure and function of cells. They can form various types of structures within cells, such as enzymes, receptors, and structural components. Lipids are another type of biomolecule, but they are not typically involved in forming cellular structures. Cellulose is a carbohydrate and is primarily found in the cell walls of plants, not in the structures within cells. Fatty acid chains are components of lipids, but they do not form structures on their own.

Enzymes are biological catalysts that speed up chemical reactions by lowering the activation energy required for the reaction to occur. Therefore, enzymes primarily affect the rate of a chemical reaction. By providing an alternative reaction pathway with a lower activation energy, enzymes increase the speed at which reactants are converted into products. This allows reactions to occur more quickly and efficiently, without being consumed or permanently altered in the process.

Mitochondria and chloroplasts are both organelles involved in energy conversion. Mitochondria are responsible for cellular respiration, where they convert nutrients into ATP, the main energy currency of cells. Chloroplasts, on the other hand, are found in plant cells and are responsible for photosynthesis, where they convert sunlight into chemical energy in the form of glucose. Therefore, both organelles play a crucial role in energy conversion processes within cells.

The cell shown in Figure 3.1 is identified as eukaryotic. Eukaryotic cells are characterized by having a true nucleus, membrane-bound organelles, and multiple linear chromosomes. This type of cell is found in plants, animals, fungi, and protists. The presence of a clearly defined nucleus and other membrane-bound organelles in the cell shown in Figure 3.1 suggests that it is eukaryotic.

When atoms in molecules share pairs of electrons, they form a covalent bond. In a covalent bond, the atoms share electrons in order to achieve a stable electron configuration. This sharing of electrons allows both atoms to fill their outer electron shells and become more stable. Ionic bonds involve the transfer of electrons from one atom to another, hydrogen bonds are weak attractions between hydrogen atoms and other electronegative atoms, and polymers are large molecules made up of repeating subunits. Therefore, the correct answer is covalent bond.

A concentration gradient refers to the difference in the concentration of dissolved particles between two locations. It represents the change in concentration over a distance and is often seen in processes such as diffusion or osmosis.

Chemical reactions involve the breaking and forming of chemical bonds, leading to the transformation of substances into different substances. During a chemical reaction, the bonds between atoms are broken, and new bonds are formed, resulting in the rearrangement of atoms and the creation of new compounds. Chemical equilibrium refers to a state where the forward and reverse reactions occur at equal rates, but it does not necessarily involve the formation of different substances. Ion formation and hydrogen bonding are specific types of chemical interactions, but they do not encompass the overall process of substances changing into different substances.

The structure labeled C in Fig. 3.3 is the endoplasmic reticulum. The endoplasmic reticulum is a network of membranes found in the cytoplasm of eukaryotic cells. It is involved in various cellular processes, including protein synthesis, lipid metabolism, and detoxification of drugs and toxins. It can be further classified into rough endoplasmic reticulum (RER), which is studded with ribosomes and involved in protein synthesis, and smooth endoplasmic reticulum (SER), which lacks ribosomes and is involved in lipid metabolism and detoxification.

In step 2 of the lock-and-key model of enzyme function, the enzyme is causing new bonds to form between the substrates. This means that the enzyme is facilitating the reaction by bringing the substrates together in the correct orientation, allowing them to interact and form new chemical bonds. This step is crucial for the catalyzed reaction to occur efficiently and produce the desired product.

The correct answer is "regulate what goes in/out of a cell." The diagram shows a structure that is responsible for controlling the movement of substances into and out of a cell. This process is known as cellular transport and is essential for maintaining the cell's internal environment and allowing it to interact with its surroundings. The structure shown in the diagram likely includes various components such as membrane proteins and channels that facilitate the selective transport of molecules across the cell membrane.

The word "layered" best describes the structure of the cell membrane because it is composed of a double layer of phospholipids. These phospholipids arrange themselves in a bilayer, with their hydrophilic heads facing outward and their hydrophobic tails facing inward. This layered structure provides stability and allows the cell membrane to regulate the movement of substances in and out of the cell.

Facilitated diffusion is the process in which molecules move across the cell membrane from an area of higher concentration to an area of lower concentration, with the help of specific transport proteins. Unlike active transport, which requires energy, facilitated diffusion does not require any energy from the cell. Therefore, it is the process that does not require energy from the cell.

The organisms living in and around the log, such as fungi, termites, pill bugs, ants, slugs, and earthworms, represent a community. A community refers to a group of different species living in the same area and interacting with each other. In this case, the organisms are all found in close proximity to each other and are likely dependent on each other for resources and habitat. Therefore, they form a community within the ecosystem of the log.

During an experiment, the factors that are observed and measured are known as dependent variables. These variables are influenced by the independent variables, which are manipulated by the researcher. The dependent variables are the outcomes or responses that are measured to determine the effect of the independent variables. Constants, on the other hand, are factors that are kept consistent throughout the experiment to ensure that any changes in the dependent variables are solely due to the manipulation of the independent variables. Hypotheses, although important in the experimental process, are not directly observed or measured during the experiment.

Mutualism is a type of symbiotic relationship where both organisms involved benefit from each other. In this case, the doctor prescribed leach therapy to remove blood from the person suffering from a blood disorder. While the leaches benefit by obtaining a meal, the person is also helped because the therapy helps to alleviate their blood disorder. Therefore, both the person and the leaches benefit from this interaction, making it an example of mutualism.

If the Daphnia, which are the primary consumers, are killed with pesticides, it will disrupt the food chain in the pond. As the primary consumers, Daphnia feed on the primary producers, which are the green algae Spirogyra. With the absence of Daphnia, the Spirogyra population will likely increase as there are no longer any organisms consuming them. This increase in Spirogyra population will then lead to an increase in the population of the primary consumer, the bluegill, as they will have more food available. However, since the smallmouth bass is the tertiary consumer and relies on the bluegill as a food source, the absence of Daphnia will eventually result in the smallmouth bass population dying out.

Carbohydrates are the molecules found in the food we eat that are most commonly broken down to make ATP. ATP is the main source of energy for our cells, and carbohydrates are the preferred source of fuel for energy production. When we consume carbohydrates, they are broken down into glucose, which is then used in cellular respiration to produce ATP. Carbohydrates provide a quick and readily available source of energy compared to lipids and proteins, which require more complex processes for energy production. Vitamins, on the other hand, do not provide energy directly but play essential roles in various metabolic processes.

During the last part of M phase in an animal cell, a cleavage furrow would begin developing. This is because during cytokinesis, which occurs after the nuclear division in M phase, the cell starts to divide into two daughter cells. The cleavage furrow is a groove that forms on the cell surface, and it marks the site of cell division. As the furrow deepens, it eventually separates the two daughter cells completely. Therefore, the development of a cleavage furrow is a crucial step in the process of cell division in animal cells.

Secondary succession can occur where a disturbance has left soil intact. This means that after a disturbance, such as a fire or flood, where the soil is still present, secondary succession can take place. In secondary succession, new plant and animal species gradually colonize the area and replace the previous community. This is different from primary succession, which occurs in areas where there is no soil, such as on bare rock or newly formed volcanic islands. Primary succession starts with pioneer species, which are the first organisms to colonize the area.

A solution that is hypotonic to a cell has fewer solutes than the cell. This means that the concentration of solutes in the solution is lower compared to the concentration of solutes inside the cell. As a result, water will move into the cell through osmosis, causing the cell to swell or potentially burst if the osmotic pressure becomes too high.

If an organic molecule model contains carbon atoms arranged in a long chain, it is probably a model of a lipid. Lipids are organic molecules that are characterized by long carbon chains, often with hydrogen atoms attached. They are an important component of cell membranes and serve as a source of energy in the body. Lipids include substances such as fats, oils, and waxes.