1.
Which type of transport is shown in the diagram?
Correct Answer
B. Active transport
Explanation
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, the transport process is shown to be moving molecules from an area of lower concentration to an area of higher concentration, which is characteristic of active transport.
2.
The difference in the concentration of dissolved particles from one location to another is called a ___.
Correct Answer
A. Concentration gradient
Explanation
A concentration gradient refers to the difference in the concentration of dissolved particles between two locations. It represents how the concentration changes from one point to another, with higher concentration areas having a steeper gradient. This term is commonly used in various scientific fields, such as biology and chemistry, to describe the movement of substances or the distribution of solutes in a solution.
3.
Scientists use observations and data to form and test ___.
Correct Answer
B. Hypotheses
Explanation
Scientists use observations and data to form and test hypotheses. Hypotheses are educated guesses or proposed explanations for a phenomenon based on existing knowledge and observations. Scientists formulate hypotheses to guide their research and experiments, and then collect data to either support or refute these hypotheses. This process helps scientists advance their understanding of the natural world and develop new theories or conclusions based on the evidence gathered.
4.
During an experiment, which factors are observed and measured?
Correct Answer
A. Dependent variables
Explanation
During an experiment, the factors that are observed and measured are known as dependent variables. These variables are directly influenced by the independent variables, which are manipulated by the researcher. The dependent variables are the outcomes or results that are measured or observed to determine the effect of the independent variables. Constants are factors that are kept consistent throughout the experiment to ensure that only the independent variables are affecting the dependent variables. Hypotheses, on the other hand, are proposed explanations or predictions about the relationship between the independent and dependent variables.
5.
What gives water many properties that are important to living things?
Correct Answer
B. Hydrogen bonds
Explanation
Hydrogen bonds give water many properties that are important to living things. Hydrogen bonds are formed between the positively charged hydrogen atoms of one water molecule and the negatively charged oxygen atoms of neighboring water molecules. These bonds give water a high boiling point, allowing it to exist as a liquid at room temperature. They also give water a high specific heat, meaning it can absorb and release large amounts of heat without significantly changing in temperature. Additionally, hydrogen bonds contribute to water's cohesion and surface tension, which are important for transporting nutrients and waste in living organisms.
6.
The four main types of carbon-based molecules in organisms are carbohydrates, lipids, nucleic acids, and ___.
Correct Answer
C. Proteins
Explanation
Proteins are the fourth main type of carbon-based molecules in organisms. They are large, complex molecules made up of amino acids and are involved in various functions in the body, including structural support, enzymatic reactions, and transportation of molecules. Proteins are essential for the growth, repair, and maintenance of cells and tissues.
7.
When graphing experimental results, you should place the ______ onto the y axis.
Correct Answer
B. Dependent variables
Explanation
When graphing experimental results, the dependent variables should be placed onto the y-axis. The dependent variables are the ones that are being measured or observed in the experiment and are expected to change as a result of manipulating the independent variables. Placing the dependent variables on the y-axis allows for a clear representation of the relationship between the independent and dependent variables, as the y-axis represents the variable that is being affected by the independent variable.
8.
If an organic molecule model contains carbon atoms arranged in a long chain, it is probably a model of ___.
Correct Answer
B. A lipid
Explanation
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 their long hydrocarbon chains. These chains are made up of carbon atoms bonded together, and they are a defining feature of lipids. Starch, polar molecules, and proteins do not typically have long carbon chains, so they can be ruled out as options.
9.
Many factors should remain unchanged during an experiment. These factors are referred to as ___.
Correct Answer
C. Controlled variables
Explanation
Controlled variables are the factors in an experiment that are intentionally kept constant or unchanged. These variables are carefully controlled to ensure that they do not influence the outcome of the experiment. By keeping these variables constant, researchers can isolate the effects of the independent variable and determine its impact on the dependent variable. This helps to establish a cause-and-effect relationship and ensure that any observed changes are due to the independent variable and not other factors.
10.
DNA and RNA are two types of ___.
Correct Answer
D. Nucleic acids
Explanation
DNA and RNA are two types of nucleic acids. Nucleic acids are macromolecules that are responsible for storing and transmitting genetic information in living organisms. DNA (deoxyribonucleic acid) is found in the nucleus of cells and carries the genetic instructions for the development and functioning of all living organisms. RNA (ribonucleic acid) is involved in the process of protein synthesis and helps in translating the genetic information stored in DNA into functional proteins. Therefore, the correct answer is nucleic acids.
11.
The smallest basic unit of matter is the ___.
Correct Answer
A. Atom
Explanation
An atom is the smallest basic unit of matter. It is composed of protons, neutrons, and electrons. Atoms combine to form molecules, which are the building blocks of all substances. Cells are the basic units of life, but they are not the smallest units of matter. Compounds are formed when atoms of different elements combine chemically. Therefore, the correct answer is atom.
12.
Which of the following is formed when an atom gains or loses electrons?
Correct Answer
D. Ion
Explanation
An ion is formed when an atom gains or loses electrons. This process causes the atom to become electrically charged, either positively or negatively. When an atom gains electrons, it becomes a negatively charged ion, called an anion. Conversely, when an atom loses electrons, it becomes a positively charged ion, called a cation. Therefore, an ion is the correct answer in this case.
13.
Atoms in molecules share pairs of electrons when they make ___.
Correct Answer
B. Covalent bond
Explanation
Atoms in molecules share pairs of electrons when they make covalent bonds. In a covalent bond, atoms share electrons in order to achieve a stable electron configuration. This sharing of electrons allows both atoms to fill their outermost energy levels and become more stable. This type of bond is commonly found in molecules and compounds composed of nonmetals. Ionic bonds involve the transfer of electrons, hydrogen bonds are a type of intermolecular bond, and polymers are large molecules made up of repeating subunits.
14.
Substances are changed into different substances when bonds break and reform during ___.
Correct Answer
B. Chemical reactions.
Explanation
Chemical reactions involve the breaking and formation of bonds between atoms, resulting in the transformation of substances into different substances. During a chemical reaction, the original bonds are broken, and new bonds are formed, leading to the rearrangement of atoms and the creation of new compounds. This process is responsible for the conversion of reactants into products and is the fundamental concept behind chemical changes. Therefore, chemical reactions are the correct answer for substances changing into different substances.
15.
Fats, oils, and cholesterol are all types of ___.
Correct Answer
B. Lipids.
Explanation
Fats, oils, and cholesterol are all types of lipids. Lipids are a class of organic compounds that are insoluble in water but soluble in organic solvents. They are an essential component of living cells and play important roles in energy storage, insulation, and cushioning of organs. Hormones, cell membranes, and fatty acids are all related to lipids, but they are not inclusive of all types of lipids.
16.
Protein polymers are made of a series of ___.
Correct Answer
A. Amino acids
Explanation
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 into specific 3D structures to become 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.
17.
The activation energy needed for a chemical reaction is decreased by a ___.
Correct Answer
A. Catalyst
Explanation
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 pathway for the reaction that has a lower energy barrier. Therefore, the presence of a catalyst decreases the activation energy needed for the reaction to proceed, making it easier for the reactants to overcome the energy barrier and form the products.
18.
In the lock-and-key model of enzyme function shown in Figure 2.2, what is happening in step 2?
Correct Answer
C. The enzyme is causing new bonds to form between the substrates.
Explanation
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 catalysis of the reaction and the formation of the desired product.
19.
Which aspect of a chemical reaction is affected by enzymes?
Correct Answer
B. Rate
Explanation
Enzymes are biological catalysts that speed up the rate of chemical reactions. They do this by lowering the activation energy required for the reaction to occur, thus increasing the rate at which reactants are converted into products. Therefore, the aspect of a chemical reaction that is affected by enzymes is the rate at which the reaction occurs.
20.
What pH would be considered a strong base?
Correct Answer
D. 12
Explanation
A pH of 12 would be considered a strong base. The pH scale ranges from 0 to 14, with values below 7 being acidic, 7 being neutral, and values above 7 being basic. As the pH scale is logarithmic, each whole number increase represents a tenfold increase in alkalinity. Therefore, a pH of 12 indicates a high concentration of hydroxide ions and a strong base.
21.
Which of the following molecules found in the food we eat is most commonly broken down to make ATP (providing us with the most readily available energy)?
Correct Answer
A. Carbohydrates
Explanation
Carbohydrates are the molecules found in food that are most commonly broken down to make ATP, providing us with readily available energy. This is because carbohydrates are easily converted into glucose, which is then used by cells to produce ATP through cellular respiration. Lipids, proteins, and vitamins can also be broken down for energy, but carbohydrates are the preferred source due to their efficiency in ATP production.
22.
Which of the following is a major principle upon which cell theory is based?
Correct Answer
C. All organisms are made of cells.
Explanation
The major principle upon which cell theory is based is that all organisms are made of cells. This principle states that cells are the basic structural and functional units of all living things. It emphasizes that all living organisms, from simple bacteria to complex multicellular organisms, are composed of cells. This principle was established by scientists Schleiden and Schwann in the 19th century and is a fundamental concept in biology.
23.
Identify the type of cell shown in Figure 3.1.
Correct Answer
D. Eukaryotic
Explanation
The correct answer is eukaryotic. This is because eukaryotic cells are characterized by having a true nucleus, membrane-bound organelles, and a more complex structure compared to prokaryotic cells. Bacterial cells are prokaryotic, meaning they lack a true nucleus and membrane-bound organelles. Animal cells are a type of eukaryotic cell, but the given figure does not provide enough information to specifically identify it as an animal cell. Therefore, the most accurate answer is eukaryotic.
24.
Which organelle is the storehouse for a cell's genetic information?
Correct Answer
D. Nucleus
Explanation
The nucleus is the storehouse for a cell's genetic information. It contains the cell's DNA, which carries the instructions for the cell's functions and characteristics. The DNA is organized into chromosomes and is protected within the nucleus. The nucleus also plays a role in regulating gene expression and controlling the cell's activities. Mitochondria and chloroplasts are involved in energy production and centrioles play a role in cell division, but they do not store genetic information like the nucleus does.
25.
Which phrase best describes rough ER?
Correct Answer
A. Studded with ribosomes
Explanation
Rough ER is described as "studded with ribosomes" because it contains ribosomes on its surface. These ribosomes are responsible for protein synthesis, making rough ER involved in the production and processing of proteins. The rough appearance of the ER is due to the presence of ribosomes, which gives it a "studded" appearance.
26.
Which organelles supply energy to the cell?
Correct Answer
C. Mitochondria
Explanation
Mitochondria are the organelles that supply energy to the cell. They are often referred to as the "powerhouses" of the cell because they produce the majority of the cell's energy in the form of ATP through a process called cellular respiration. Mitochondria have their own DNA and are capable of self-replication. They are found in most eukaryotic cells and play a vital role in various cellular processes, including metabolism and the regulation of cell death. Ribosomes, centrosomes, and vacuoles do not directly supply energy to the cell.
27.
Which organelles contain enzymes that break down old cell parts?
Correct Answer
C. Lysosomes
Explanation
Lysosomes contain enzymes that break down old cell parts. Lysosomes are membrane-bound organelles found in animal cells. They are responsible for breaking down waste materials, cellular debris, and old or damaged organelles through a process called autophagy. This process helps maintain the overall health and functioning of the cell by recycling and eliminating unnecessary or damaged components.
28.
Which organelles are found only in plant cells?
Correct Answer
A. Chloroplasts
Explanation
Chloroplasts are organelles that are 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 gives plants their green color and allows them to absorb sunlight. This organelle is not found in animal cells, making it unique to plant cells. Centrosomes, ribosomes, and vacuoles, on the other hand, can be found in both plant and animal cells.
29.
When do sister chromatids separate in mitosis?
Correct Answer
B. AnapHase
Explanation
In mitosis, sister chromatids separate during anaphase. During this phase, the microtubules attached to the centromeres shorten, pulling the sister chromatids apart and towards opposite ends of the cell. This ensures that each daughter cell receives a complete set of chromosomes. In contrast, metaphase is the phase where the sister chromatids align at the center of the cell, prophase is the phase where the chromosomes condense and the nuclear envelope breaks down, and telophase is the phase where the nuclear envelope reforms and the chromosomes decondense.
30.
Which of the following is a network of proteins that supports and gives shape to the cell?
Correct Answer
C. Cytoskeleton
Explanation
The cytoskeleton is a network of proteins that provides structural support to the cell and helps maintain its shape. It also plays a crucial role in cell movement, cell division, and the transport of materials within the cell. Vesicles are small membrane-bound sacs involved in transport, while vacuoles are storage organelles. The cytoplasm is the gel-like substance that fills the cell. Therefore, the correct answer is cytoskeleton.
31.
Transport proteins play a role in both ___.
Correct Answer
A. Passive and active transport
Explanation
Transport proteins are responsible for facilitating the movement of molecules across cell membranes. They can transport molecules through both passive and active mechanisms. Passive transport refers to the movement of molecules from an area of higher concentration to an area of lower concentration, without the need for energy. Active transport, on the other hand, involves the movement of molecules against their concentration gradient, requiring the input of energy. Therefore, the correct answer is "passive and active transport."
32.
A solution that is hypotonic to a cell has ___.
Correct Answer
B. Fewer solutes than the cell
Explanation
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 influx of water is excessive.
33.
What is the term for the diffusion of water across a semipermeable membrane?
Correct Answer
A. Osmosis
Explanation
Osmosis is the correct answer because it refers to the process of water molecules moving from an area of lower solute concentration to an area of higher solute concentration through a semipermeable membrane. This movement of water helps to equalize the concentration of solutes on both sides of the membrane, resulting in the establishment of equilibrium. The other options, such as equilibrium, transport, and isotonic, do not specifically describe the diffusion of water across a semipermeable membrane.
34.
What is the main function of the Golgi apparatus?
Correct Answer
C. Process and deliver proteins
Explanation
The Golgi apparatus is responsible for processing and delivering proteins within the cell. It receives proteins from the endoplasmic reticulum, modifies them by adding sugars and other molecules, and packages them into vesicles for transport to their final destinations. This process ensures that proteins are properly folded, modified, and sorted before being sent to different parts of the cell or secreted outside. Therefore, the main function of the Golgi apparatus is to process and deliver proteins.
35.
Which phrase best describes the property of selective permeability?
Correct Answer
A. Some molecules pass
Explanation
Selective permeability refers to the property of a membrane or barrier to allow only certain molecules or ions to pass through while restricting the passage of others. In this case, the correct answer "some molecules pass" accurately describes selective permeability as it implies that only certain molecules are able to pass through the barrier, while others are not able to do so.
36.
Which process divides the cytoplasm?
Correct Answer
B. Cytokinesis
Explanation
Cytokinesis is the process that divides the cytoplasm during cell division. It occurs after the chromosomes have separated and the nucleus has divided. During cytokinesis, the cytoplasm is divided into two daughter cells, each containing a complete set of chromosomes. This process ensures that each daughter cell receives the necessary organelles and cellular components to function independently. Anaphase, S phase, and telophase are all different stages of cell division but do not specifically involve the division of the cytoplasm.
37.
Mitochondria and chloroplasts are both sites of ___.
Correct Answer
A. Energy conversion.
Explanation
Mitochondria and chloroplasts are both organelles involved in energy conversion. Mitochondria are responsible for cellular respiration, where they convert nutrients into ATP, the cell's main energy source. 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 mitochondria and chloroplasts play a crucial role in energy conversion within cells.
38.
Which word best describes the structure of the cell membrane?
Correct Answer
A. Layered
Explanation
The word "layered" best describes the structure of the cell membrane because it is composed of a double layer of phospholipids. These phospholipids form 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.
39.
Which process requires no energy from the cell?
Correct Answer
D. Facilitated diffusion
Explanation
Facilitated diffusion is the process by which molecules passively move across the cell membrane with the help of transport proteins. Unlike active transport, which requires energy to move molecules against their concentration gradient, facilitated diffusion does not require any energy from the cell. Therefore, facilitated diffusion is the correct answer as it is the only process listed that does not require energy.
40.
Which of the following statements about succession is correct?
Correct Answer
C. Secondary succession can occur where a disturbance has left soil intact.
Explanation
Secondary succession refers to the process of ecological succession that occurs in an area where a previous community has been disrupted or destroyed, but the soil remains intact. This can happen after events such as wildfires, hurricanes, or logging. In these cases, the soil already contains nutrients and a seed bank, allowing for the establishment of new plant species. Primary succession, on the other hand, occurs in areas where soil is not present or has been completely removed, such as on bare rock or sand dunes. Therefore, the statement "Secondary succession can occur where a disturbance has left soil intact" is correct.
41.
While on the nature trail, a student turns over a rotted log. Fungi, termites, pill bugs, ants, slugs, and earthworms are observed living in and around the log. Altogether, these organisms represent a ___.
Correct Answer
A. Community
Explanation
The student's observation of various organisms living in and around the rotted log suggests that they are all part of a community. A community refers to a group of different species that interact and coexist in a particular area. In this case, the fungi, termites, pill bugs, ants, slugs, and earthworms are all living together and interacting within the same habitat, forming a community.
42.
A doctor prescribed leach therapy (purposefully allowing leaches to remove blood) for a person suffering from a blood disorder, resulting in the person being helped. This would then be an example of
Correct Answer
C. Mutualism
Explanation
In this scenario, the doctor prescribed leach therapy with the intention of helping the person suffering from a blood disorder. Leach therapy involves allowing leaches to remove blood, which in turn benefits the person by alleviating their condition. This demonstrates mutualism, as both parties involved (the person and the leaches) benefit from the interaction. The person's blood disorder is improved, while the leaches obtain a source of nutrition.
43.
In a pond...
1) the primary producer is a green alga, Spirogyra,
2) the primary consumer is the crustacean, Daphnia,
3) the secondary consumer is a small fish, the bluegill, and
4) the tertiary consumer is a larger fish, the smallmouth bass.
What changes can be expected in the pond if the Daphnia are killed with pesticides?
Correct Answer
D. The smallmouth bass population will die.
Explanation
If the Daphnia are killed with pesticides, the primary consumer in the pond will be eliminated. As a result, the primary producer, Spirogyra, will not be consumed and its population will likely increase. With the increase in Spirogyra population, the primary consumer, Daphnia, will not be able to eat something else and its population will decline. Consequently, the secondary consumer, bluegill, will have less food available and its population will probably decrease. As the bluegill population decreases, the tertiary consumer, smallmouth bass, will also have less food and may not be able to survive, leading to the death of the smallmouth bass population.
44.
Scientists found that, over a period of 200 years, a mountain pond was transformed into a meadow. During that time, several communities of organisms were replaced by different communities. Which of these best explains why new communities were able to replace older communities?
Correct Answer
C. The abiotic characteristics of the habitat changed.
Explanation
The correct answer is that the abiotic characteristics of the habitat changed. This means that the non-living factors in the environment, such as temperature, moisture, and soil composition, underwent significant alterations over time. These changes likely created new conditions that were more suitable for different communities of organisms to thrive, leading to the replacement of the older communities. It is important to note that the other options, such as extinction of the original species or the disappearance of diseases, may have influenced the changes in communities, but they do not directly explain why new communities were able to replace the older ones.
45.
The carrying capacity of a population in an ecosystem is ___.
Correct Answer
C. An average maximum number of individuals of a population that an ecosystem supports.
Explanation
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 can no longer sustain any additional individuals, resulting in a balance between births and deaths. It is not related to the rate at which individuals die off, the amount of animals in the entire biome, or how an ecosystem can carry a population to another ecosystem.
46.
In Fig. 3.3, identify the structure labeled C.
Correct Answer
D. Endoplasmic Reticulum
Explanation
The structure labeled C in Fig. 3.3 is the Endoplasmic Reticulum.
47.
During the last part of M phase in an animal cell, the ___ would begin developing.
Correct Answer
C. A cleavage furrow
Explanation
During the last part of M phase in an animal cell, a cleavage furrow would begin developing. This is because during cytokinesis, which is the final stage of M phase, the cell membrane starts to pinch inwards at the equator of the cell. This furrow eventually deepens and separates the parent cell into two daughter cells. The development of a cleavage furrow is a crucial step in cell division and ensures the proper distribution of genetic material to the daughter cells.
48.
In Fig. 3.3, identify the structure labeled F.
Correct Answer
A. Hold water
Explanation
The structure labeled F in Figure 3.3 is responsible for holding water.
49.
What is the function of the entire structure shown in the diagram?
Correct Answer
B. Regulate what goes in/out of a cell
Explanation
The entire structure shown in the diagram is responsible for regulating what goes in and out of a cell. This suggests that it is involved in maintaining the cell's internal environment and controlling the movement of substances across the cell membrane. It may include various components such as transport proteins, ion channels, and receptors that help in the selective transport of molecules and ions.
50.
The structures labeled B would be made of ___.
Correct Answer
B. Protein
Explanation
The structures labeled B would be made of protein. This is because proteins are a class of macromolecules that are composed of amino acids. They play a crucial role in the structure and function of cells, and are involved in various biological processes. Therefore, it is likely that the structures labeled B are composed of protein.