1.
Inside the human body, heat is constantly generated as a byproduct of chemical reactions. Human must be able to release heat to the environment. The adaptation is necessary for maintaining _______________________________ .
Correct Answer
C. Homeostasis
Explanation
The adaptation is necessary for maintaining homeostasis. Homeostasis refers to the body's ability to maintain a stable internal environment despite external changes. In this case, the body needs to release heat to the environment in order to regulate its temperature and prevent overheating. This is crucial for the body to function properly and maintain a balanced state.
2.
Sugar dissolves in or mixes completely with water. The solubility of a substance in water is determined by measuring the maximum amount of substance that dissolves in a given amount of water at a given temperature. Hypothesis: The solubility of sugar in water decreases. Identify the independent variable and the dependent variable that you would use to test this hypothesis.
Correct Answer
C. Dependent variable - amount of sugar that dissolves; independent variable - water temperature
Explanation
The hypothesis states that the solubility of sugar in water decreases. To test this hypothesis, the dependent variable would be the amount of sugar that dissolves, as this is what is being measured and observed. The independent variable would be the water temperature, as it is being manipulated and controlled to see its effect on the solubility of sugar.
3.
A scientist performs a series of experiments to confirm an idea regarding cellular metabolism. The results of the experiments support the scientist's initial idea, and after conferring with colleagues, the scientist discovers that evidence from many experiments has supported the same idea. This idea could now be considered a(n) _______________
Correct Answer
A. Theory
Explanation
The correct answer is theory. In this scenario, the scientist performs experiments to confirm an idea regarding cellular metabolism. The results of these experiments support the scientist's initial idea, and after discussing with colleagues, the scientist learns that evidence from many experiments has also supported the same idea. Based on this accumulation of evidence, the idea can now be considered a theory. A theory is a well-substantiated explanation of some aspect of the natural world that is based on a body of evidence and can be used to make predictions or explanations.
4.
In an experiment, all variables are held constant except one. The, experimental results from testing are compared based on that one variable. What type of experiment is this?
Correct Answer
C. A controlled experiment
Explanation
A controlled experiment is an experiment where all variables, except one, are kept constant. This allows researchers to isolate the effect of that specific variable and compare the experimental results based on it. By controlling all other factors, the researchers can determine whether the observed changes are due to the manipulated variable or other external factors.
5.
A biochemist is performing an experiment to determine the effect of chemical X on the growth of bacteria. Which test tube is the control?
Correct Answer
A. Test Tube 1
Explanation
Test Tube 1 is the control because it does not contain chemical X. In an experiment, the control group is used as a baseline to compare the results of the experimental groups. By not adding chemical X to Test Tube 1, the biochemist can observe the natural growth of bacteria without any external factors influencing it. This allows for a comparison to be made between the growth of bacteria in the other test tubes that do contain chemical X, helping to determine the effect of chemical X on bacterial growth.
6.
A scientist uses graphs, tables, and charts to publish research results. What type of research was he or she probably performing?
Correct Answer
B. Quantitative research
Explanation
The scientist is most likely performing quantitative research because graphs, tables, and charts are commonly used to present numerical data and statistics in this type of research. Quantitative research focuses on collecting and analyzing numerical data to draw conclusions and make generalizations.
7.
Some cattle were given bovine growth hormone (BGH) to see if they would produce more meat. The animals were studied over a period of two years. Animals in Group A were injected with BGH. Animals in Group B were not injected with BGH. The table shows the results of the investigation. Which is a valid conclusion from this data?
Correct Answer
C. Animals injected with the hormone will increase in mass faster than those who are not injected.
Explanation
The table shows that the animals in Group A, which were injected with BGH, had a higher increase in mass compared to the animals in Group B, which were not injected with BGH. This suggests that the hormone has a positive effect on increasing mass. Therefore, the valid conclusion from this data is that animals injected with the hormone will increase in mass faster than those who are not injected.
8.
The results of an experiment show that as temperature increases, enzyme activity decreases. Which graph correctly displays these findings?
Correct Answer
D. GrapH D
Explanation
Graph D correctly displays the findings that as temperature increases, enzyme activity decreases. In Graph D, as the temperature increases from left to right, the enzyme activity decreases steadily. This is indicated by the downward slope of the line on the graph. The other graphs (A, B, and C) either show no clear relationship between temperature and enzyme activity or display an incorrect trend where enzyme activity increases with temperature. Therefore, Graph D is the correct representation of the given findings.
9.
Which graph shows optimal enzyme activity at 50 degrees celsius?
Correct Answer
B. GrapH B
Explanation
Graph B shows optimal enzyme activity at 50 degrees Celsius because it has the highest point on the graph, indicating the maximum enzyme activity at that temperature. The other graphs either have lower enzyme activity at 50 degrees Celsius or do not show a clear peak at that temperature.
10.
Which does a polymer most closely resemble?
Correct Answer
C. Chain
Explanation
A polymer is a large molecule made up of repeating subunits called monomers. Just like a chain, a polymer consists of multiple units linked together in a linear fashion. Each monomer acts as a "link" in the polymer chain, similar to how links connect to form a chain. Therefore, a polymer most closely resembles a chain.
11.
Different organisms store glucose in various forms. You discover a new species. Upon chemical analysis, you find that it is comprised of significant amounts of starch. To which organism might this new species be related?
Correct Answer
B. Potato
Explanation
The presence of significant amounts of starch in the new species suggests that it is related to the potato. Starch is a common form of glucose storage in plants, including potatoes. Ferns do not typically store glucose as starch, and dogs and bacteria do not store glucose in the form of starch at all. Therefore, the new species is most likely related to the potato.
12.
Which is NOT true of lipids?
Correct Answer
D. They are polar.
Explanation
Lipids are commonly called fats and oils, they are hydrophobic, and they are good for energy storage. However, lipids are not polar. Polar molecules have a positive and negative end, while lipids are nonpolar molecules that do not have charged ends.
13.
A student drew and labeled the graph below based on the results of an experiment. Why did the student include the labels activation energy and energy released?
Correct Answer
C. To explain why the experiment gave off heat and is exothermic
Explanation
The student included the labels "activation energy" and "energy released" to explain why the experiment gave off heat and is exothermic. Activation energy refers to the minimum amount of energy required for a chemical reaction to occur. By including this label, the student is indicating that the reaction needed heat to occur. The label "energy released" suggests that during the reaction, energy was released in the form of heat, indicating that the reaction is exothermic.
14.
What makes a water molecule polar?
Correct Answer
C. A water molecule has a slight charge on each end.
Explanation
A water molecule is polar because it has a slight charge on each end. This is due to the unequal distribution of electrons between the oxygen and hydrogen atoms in the molecule. The oxygen atom attracts the shared electrons more strongly, giving it a partial negative charge, while the hydrogen atoms have a partial positive charge. This polarity allows water molecules to form hydrogen bonds with each other, giving water its unique properties such as high surface tension and the ability to dissolve many substances.
15.
Which is true about enzymes?
Correct Answer
C. They can speed up metabolic processes in the body.
Explanation
Enzymes are biological catalysts that can speed up metabolic processes in the body. They do this by lowering the activation energy required for a reaction to occur, allowing the reaction to happen more quickly. Enzymes are highly specific in their action and can recognize and bind to specific substrates. After a reaction, enzymes are not consumed or changed, so they can be reused multiple times. Enzymes are also capable of changing their shape to accommodate the substrate, which is essential for their function.
16.
The diagram below shows two amino acids. What would biochemists call the result of chaining many of these molecules together?
Correct Answer
D. A protein
Explanation
The diagram shows two amino acids, which are the building blocks of proteins. Biochemists would call the result of chaining many of these molecules together a protein. Proteins are large, complex molecules made up of long chains of amino acids. They play a crucial role in various biological processes and are involved in the structure, function, and regulation of cells and tissues in the body.
17.
The diagram below illustrates a biochemical process that occurs in organisms. The substance labeled catalyst also is known by what other name?
Correct Answer
B. Enzyme
Explanation
The substance labeled catalyst in the diagram is known as an enzyme. Enzymes are biological catalysts that speed up biochemical reactions in organisms. They are typically proteins that facilitate chemical reactions by lowering the activation energy required for the reaction to occur. Enzymes are specific in their function and can be reused multiple times. They play a vital role in various biological processes, such as digestion, metabolism, and cellular respiration.
18.
You are analyzing a compound in a laboratory. You find that it is made up of carbon, hydrogen, and oxygen in a ratio of one carbon, two hydrogen, and one oxygen atom. How will you classify the compound?
Correct Answer
A. Carbohydrate
Explanation
Based on the given information, the compound is made up of carbon, hydrogen, and oxygen in a ratio of 1:2:1. This matches the general formula for carbohydrates, which are organic compounds composed of carbon, hydrogen, and oxygen, with the ratio of hydrogen to oxygen atoms being 2:1, just like in this case. Therefore, the compound can be classified as a carbohydrate.
19.
A recipe says to mix 100 g of sugar, a pinch of NaCl, and 1 g vanilla flavoring in 113 g of butter. Which ingredient is the solvent?
Correct Answer
B. Butter
Explanation
In this recipe, the solvent is the substance that dissolves the other ingredients. The butter is the only ingredient mentioned that has the ability to dissolve the sugar, NaCl, and vanilla flavoring. Therefore, the butter is the solvent in this mixture.
20.
In the following equation, what are the products of the reaction?
Correct Answer
D. Carbon dioxide and water
Explanation
When sugar reacts with oxygen, the products of the reaction are carbon dioxide and water. This is a combustion reaction, where sugar (a carbohydrate) is oxidized by oxygen to produce carbon dioxide and water.
21.
You suspect that a chemical that you are testing in the lab is strongly acidic. What might be its pH?
Correct Answer
A. 2
Explanation
A pH value of 2 indicates a strongly acidic solution. The pH scale ranges from 0 to 14, with values below 7 considered acidic. A pH of 2 suggests a high concentration of hydrogen ions, indicating a strong acidity.
22.
Which class of macromolecules store and communicate genetic information?
Correct Answer
A. Carbohydrates
23.
Which structure serves to support the cell from the inside?
Correct Answer
B. Cytoskeleton
Explanation
The cytoskeleton serves to support the cell from the inside. It is a network of protein filaments that provide structural support and maintain the shape of the cell. Additionally, the cytoskeleton is involved in cell movement, cell division, and the transport of materials within the cell.
24.
An environmental toxin is discovered that interferes with certain cellular functions of a plant cell. When affected cells are examined, it is observed that proteins that are normally found on the plasma membrane are instead found in the cytoplasm. Other proteins are also located improperly. Which structure is most likely affected by the toxin?
Correct Answer
D. Cell wall
Explanation
The cell wall is most likely affected by the toxin. The cell wall is responsible for maintaining the shape and providing structural support to plant cells. It also acts as a barrier and regulates the movement of substances in and out of the cell. If proteins that are normally found on the plasma membrane are instead found in the cytoplasm, it suggests that the cell wall is not functioning properly, allowing these proteins to be misplaced.
25.
Why do many scientists think that prokaryotes are similar to the first organisms on Earth?
Correct Answer
C. Prokaryote cells have no nucleus.
Explanation
Many scientists believe that prokaryotes are similar to the first organisms on Earth because they have no nucleus. The absence of a nucleus is a characteristic of prokaryotic cells, which are considered to be simpler and more primitive than eukaryotic cells. It is believed that the first organisms on Earth were simple, single-celled organisms without a nucleus, similar to prokaryotes. Therefore, the lack of a nucleus in prokaryotic cells supports the idea that they are similar to the first organisms on Earth.
26.
Which statement would NOT be included in a summary of the cell theory?
Correct Answer
B. All cells contain a nucleus that controls cell division.
Explanation
The statement "All cells contain a nucleus that controls cell division" would not be included in a summary of the cell theory because it is not a universally accepted component of the theory. While many cells do contain a nucleus that controls cell division, there are also cells, such as prokaryotic cells, that do not have a nucleus but still undergo cell division. The cell theory primarily focuses on the concepts that the cell is the basic unit of organization, all organisms are made up of at least one cell, and all cells come from preexisting cells.
27.
Which letter in the diagram below indicates the structure that is most closely associated with protein building?
Correct Answer
C. C
Explanation
The letter C in the diagram indicates the structure that is most closely associated with protein building. This is because the structure shown in letter C represents a ribosome, which is responsible for protein synthesis in cells. Ribosomes are the cellular organelles where proteins are assembled by linking amino acids together in a specific order according to the instructions provided by messenger RNA (mRNA). Therefore, the ribosome is closely associated with the process of protein building.
28.
How is the plasma membrane of a cell organized?
Correct Answer
D. Two layers of pHospHolipids, with their polar hydropHilic heads facing away from each other
Explanation
The plasma membrane of a cell is organized into two layers of phospholipids, with their polar hydrophilic heads facing away from each other. This arrangement forms a lipid bilayer, where the hydrophobic tails of the phospholipids are sandwiched between the hydrophilic heads. This structure provides a barrier that controls the movement of molecules in and out of the cell, while allowing proteins to freely move within the membrane.
29.
In which structure would you find a nucleus?
Correct Answer
B. Plant cell
Explanation
The correct answer is plant cell because plant cells are eukaryotic cells that contain a nucleus. The nucleus is a membrane-bound organelle that houses the cell's genetic material, including DNA. It is responsible for controlling the cell's activities and contains the instructions for protein synthesis and cell reproduction. Bacterial cells, prokaryotes, and viruses do not have a nucleus. Bacterial cells have a nucleoid region where their genetic material is located, prokaryotes lack a nucleus altogether, and viruses are acellular particles that do not have a nucleus.
30.
What characteristic of the plasma membrane is illustrated in this drawing?
Correct Answer
A. Selective permeability
Explanation
The characteristic of the plasma membrane illustrated in this drawing is selective permeability. This means that the membrane allows only certain substances to pass through while preventing the passage of others. The drawing likely shows different molecules or ions selectively passing through the membrane, demonstrating its ability to control the movement of substances in and out of the cell.
31.
While viewing a slide of rapidly moving unicellular organisms, a student concludes that these organisms require a large amount of energy to maintain their activity. What organelles provide this needed energy?
Correct Answer
D. Mitochondria
Explanation
Mitochondria are the organelles responsible for providing energy to cells through the process of cellular respiration. They generate ATP, which is the main source of energy for cellular activities. Since the unicellular organisms mentioned in the question are rapidly moving, they require a large amount of energy to maintain their activity. Therefore, it can be concluded that mitochondria provide the needed energy for these organisms.
32.
On a laboratory exam, a student is asked to determine if the cells under a microscope are plant cells or animal cells. What might the student look for?
Correct Answer
A. Chloroplasts and a cell wall
Explanation
The student would look for chloroplasts and a cell wall to determine if the cells under the microscope are plant cells. Plant cells have chloroplasts, which are responsible for photosynthesis, and a cell wall that provides structural support. Animal cells do not have chloroplasts or a cell wall. Therefore, the presence of chloroplasts and a cell wall would indicate that the cells are plant cells.
33.
The diagram below represents a cell in water. Explain why more water is moving out of the cell than into the cell.
Correct Answer
C. The concentration of solute outside the cell is higher than it is inside the cell.
Explanation
The correct answer is that the concentration of solute outside the cell is higher than it is inside the cell. This difference in solute concentration creates an osmotic gradient, causing water to move out of the cell to equalize the concentration on both sides of the cell membrane.
34.
How can the cytoskeleton of a cell be described?
Correct Answer
A. Framework and anchor for organelles
Explanation
The cytoskeleton of a cell can be described as a framework and anchor for organelles. This means that it provides structural support and stability to the cell, allowing the organelles to be properly organized and positioned within the cell. The cytoskeleton also helps in cell movement and division by providing a scaffold for cellular processes. Overall, the cytoskeleton plays a crucial role in maintaining the shape and function of the cell.
35.
Which is the movement of substances through a cell membrane against a concentration gradient that requires energy?
Correct Answer
C. Active transport
Explanation
Active transport is the movement of substances through a cell membrane against a concentration gradient that requires energy. This process uses energy in the form of ATP to pump molecules or ions across the membrane, allowing them to move from an area of lower concentration to an area of higher concentration. Unlike diffusion or facilitated diffusion, active transport requires energy input and is able to move substances against their concentration gradient, allowing the cell to maintain specific internal concentrations of molecules or ions. Osmosis, on the other hand, is the movement of water molecules across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration.
36.
Which cell organelle is the control center and contains coded directions for production of proteins?
Correct Answer
D. Nucleus
Explanation
The nucleus is the control center of the cell and contains coded directions for the production of proteins. It houses the cell's genetic material, DNA, which carries the instructions for protein synthesis. The nucleus regulates the cell's activities by controlling gene expression and directing the production of specific proteins needed for various cellular functions.
37.
Which organelle is show in the picture?
Correct Answer
D. Chloroplast
Explanation
The correct answer is chloroplast. Chloroplasts are organelles found in plant cells that are responsible for photosynthesis. They contain chlorophyll, a pigment that captures sunlight and converts it into energy. In the picture, we can see a green structure, which is characteristic of chloroplasts due to the presence of chlorophyll. This organelle is responsible for the production of glucose and oxygen in plants.
38.
According to the diagram, what is the name of the structure labeled A?
Correct Answer
D. Nucleolus
Explanation
The structure labeled A in the diagram is the nucleolus. The nucleolus is a distinct region within the nucleus of a cell that is responsible for the production and assembly of ribosomes. It is often depicted as a dense, spherical structure and can be easily identified in the diagram.
39.
Using the diagram, identify the letter that represents the cell membrane.
Correct Answer
G. G
Explanation
The correct answer is G. In the diagram, G is the only letter that is positioned around the entire cell, indicating that it represents the cell membrane.
40.
Using the diagram, identify the letter that represents the lysosome.
Correct Answer
C. C
Explanation
The letter C represents the lysosome in the diagram.
41.
Using the diagram, identify the letter that represents the rough endoplasmic reticulum.
Correct Answer
H. H
Explanation
The letter H represents the rough endoplasmic reticulum. The rough endoplasmic reticulum is involved in protein synthesis and has ribosomes attached to its surface, which gives it a "rough" appearance. The diagram likely shows the different organelles within a cell, and by identifying the letter H, we can determine that it represents the rough endoplasmic reticulum.
42.
You are conducting an experiment to determine the presence of simple reducing sugars such as monosaccharides. Which indicator would you use to test for the presence of glucose?
Correct Answer
C. Benedict's solution
Explanation
Benedict's solution is used to test for the presence of reducing sugars such as glucose. When Benedict's solution is added to a sample containing glucose and heated, it undergoes a color change from blue to green, yellow, orange, or red, depending on the concentration of glucose. This color change occurs because glucose reduces the copper ions in Benedict's solution, forming a precipitate. Therefore, Benedict's solution is the appropriate indicator to test for the presence of glucose.
43.
You are conducting a test to test for the presence of protein in a sample. What test or solution would you use and what would be you indication of positive for the presence of protein.
Correct Answer
D. Biuret test; lavender to dark purple color change
Explanation
The Biuret test is used to test for the presence of protein in a sample. The indication of a positive result for the presence of protein is a color change from lavender to dark purple. This color change occurs due to the reaction between the peptide bonds in proteins and the Biuret reagent, resulting in the formation of a complex that exhibits this color change.
44.
Which organelle has the function of aiding in the division of animal cells?
Correct Answer
E. E
Explanation
Organelles are specialized structures within a cell that perform specific functions. The organelle that aids in the division of animal cells is the centriole, which is found in the centrosome. Centrioles play a crucial role in cell division by organizing the microtubules that form the spindle apparatus, which helps separate the chromosomes during mitosis and meiosis. Therefore, option E is the correct answer as it represents the centriole organelle.
45.
Which of the following is the process by which a cell takes in material by forming a vesicle at the cell membrane?
Correct Answer
B. Endocytosis
Explanation
Endocytosis is the process by which a cell takes in material by forming a vesicle at the cell membrane. During endocytosis, the cell membrane invaginates, or folds inward, to form a vesicle that surrounds the material to be taken in. This allows the cell to internalize substances from the extracellular environment. Endocytosis is an active process that requires energy and is used by cells to uptake nutrients, engulf pathogens, and regulate cell signaling. In contrast, passive transport, facilitated diffusion, and exocytosis involve the movement of materials out of the cell or across the cell membrane.
46.
According to the picture, what transport process is being illustrated?
Correct Answer
D. Exocytosis
Explanation
The picture is illustrating the process of exocytosis. Exocytosis is a transport process where vesicles fuse with the plasma membrane, releasing their contents outside the cell. In the picture, it can be observed that a vesicle is merging with the cell membrane and releasing its contents into the extracellular space. This process is characteristic of exocytosis, making it the correct answer.
47.
What structure is being shown in the image?
Correct Answer
A. pHospHolipid
Explanation
The structure being shown in the image is a phospholipid. Phospholipids are a type of lipid molecule that make up the basic structure of cell membranes. They have a hydrophilic (water-loving) head and hydrophobic (water-fearing) tails, which arrange themselves in a bilayer formation. This allows phospholipids to form a barrier between the inside and outside of cells, regulating the movement of substances in and out of the cell.
48.
The movement of molecules from an area of high concentration to an area of lower concentration by use of a protein is called _________________________ .
Correct Answer
B. Facilitated diffusion
Explanation
Facilitated diffusion is the correct answer because it involves the movement of molecules from an area of high concentration to an area of lower concentration with the help of a protein. This process does not require energy and is passive, unlike active transport. Simple diffusion refers to the movement of molecules directly through the phospholipid bilayer without the need for a protein. Osmosis, on the other hand, is the movement of water molecules across a selectively permeable membrane.
49.
DNA and RNA are two types of ____________________________ which are composed of the subunits ________________________ .
Correct Answer
D. Nucleic acids - nucleotides
Explanation
DNA and RNA are two types of nucleic acids. Nucleic acids are composed of the subunits called nucleotides. DNA and RNA are both involved in the storage and transmission of genetic information in living organisms. Nucleotides are made up of a sugar molecule, a phosphate group, and a nitrogenous base. The sequence of nucleotides in DNA and RNA determines the genetic code and plays a crucial role in protein synthesis.
50.
Using the diagram, identify the letter that represents the site of protein synthesis.
Correct Answer
A. I
Explanation
The letter "I" represents the site of protein synthesis.