1.
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
In an experiment, the control group is the group that does not receive the experimental treatment and is used as a baseline for comparison. In this case, Test Tube 1 is the control because it does not contain chemical X. By comparing the growth of bacteria in Test Tube 1 to the other test tubes that do contain chemical X, the biochemist can determine the effect of chemical X on the growth of bacteria.
2.
Which does a polymer most closely resemble?
Correct Answer
C. Chain
Explanation
A polymer most closely resembles a chain. A polymer is a large molecule made up of repeating subunits called monomers that are linked together in a linear fashion, similar to how links are connected in a chain. This structure allows polymers to have flexibility and the ability to stretch and bend, just like a chain.
3.
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 storage form of glucose in plants, and potatoes are known for their high starch content. In contrast, ferns typically store glucose as glycogen, dogs store it as glycogen and fat, and bacteria store it as glycogen or other forms. Therefore, the presence of starch points towards a plant organism like the potato.
4.
Which is NOT true of lipids?
Correct Answer
D. They are polar.
Explanation
Lipids are commonly called fats and oils because they are insoluble in water and soluble in organic solvents. They are hydrophobic, meaning they repel water. Lipids are known to be good for energy storage as they contain more energy per gram compared to carbohydrates. However, lipids are not polar molecules, as they do not have a charge separation and do not dissolve in water.
5.
What makes a water molecule polar?
Correct Answer
C. A water molecule has a slight charge on each end.
Explanation
Water molecules are polar because they have a slight charge on each end. This is due to the unequal sharing of electrons between the oxygen and hydrogen atoms in the molecule. The oxygen atom attracts the shared electrons more strongly than the hydrogen atoms, creating a partial negative charge near the oxygen atom and partial positive charges near the hydrogen atoms. 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.
6.
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. When many amino acids are linked together in a chain, it forms a protein. Therefore, biochemists would call the result of chaining many of these molecules together a protein.
7.
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 about the compound's composition of one carbon, two hydrogen, and one oxygen atom, it can be classified as a carbohydrate. Carbohydrates are organic compounds that consist of carbon, hydrogen, and oxygen atoms in a specific ratio, typically in the form of a sugar or starch.
8.
You suspect that a chemical that you are testing in the lab is strongly basic. What might be its pH?
Correct Answer
D. 14
Explanation
A pH of 14 indicates a highly alkaline or basic substance. The pH scale ranges from 0 to 14, with 7 being neutral. A pH of 14 suggests that the chemical being tested has a high concentration of hydroxide ions (OH-) compared to hydrogen ions (H+). This indicates a strong base, as it has a high capacity to accept protons and release hydroxide ions.
9.
Which class of macromolecules store and communicate genetic information?
Correct Answer
D. Nucleic acids
Explanation
Nucleic acids are the class of macromolecules that store and communicate genetic information. This is because nucleic acids, specifically DNA and RNA, contain the genetic code that determines the characteristics and functions of living organisms. DNA stores the genetic information, while RNA helps to transmit and express this information. Carbohydrates, lipids, and proteins have important roles in the body, but they do not directly store or communicate genetic information.
10.
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 simple reducing sugars such as glucose. It contains copper sulfate, which reacts with the aldehyde or ketone functional groups in reducing sugars, forming a red precipitate. This color change indicates the presence of glucose in the solution.
11.
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 correct answer is the Biuret test. This test is used to detect the presence of proteins in a sample. When the Biuret reagent is added to a solution containing protein, it forms a complex with the peptide bonds in the protein. This complex results in a color change from lavender to dark purple. Therefore, a dark purple color change indicates a positive result for the presence of protein in the sample.
12.
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 that make up the cell membrane. They consist of a hydrophilic (water-loving) head and two hydrophobic (water-repelling) tails. This structure allows phospholipids to form a bilayer in the cell membrane, with the hydrophilic heads facing outward towards the watery environment and the hydrophobic tails facing inward. This arrangement helps to maintain the integrity and fluidity of the cell membrane.
13.
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, which are composed of the subunits called nucleotides. Nucleic acids are large biomolecules that play a crucial role in storing and transmitting genetic information in living organisms. Nucleotides are the building blocks of nucleic acids, consisting of a sugar molecule (ribose in RNA and deoxyribose in DNA), a phosphate group, and a nitrogenous base (adenine, thymine, cytosine, guanine in DNA and adenine, uracil, cytosine, guanine in RNA). These nucleotides form long chains through phosphodiester bonds to create the DNA and RNA molecules.
14.
A florist place a bouquet of white carnations in water containing blue dye. After a time, the flower petals turn blue. What process helped the carnations change color?
Correct Answer
C. Cohension and adhesion of water molecules
Explanation
The cohesion and adhesion of water molecules is the process that helped the carnations change color. Cohesion refers to the attraction between water molecules, causing them to stick together, while adhesion refers to the attraction between water molecules and other substances. In this case, the water molecules adhered to the petals of the carnations and the blue dye dissolved in the water, causing the petals to absorb the blue dye and change color.
15.
The bond formed between the oxygen of one water molecule to the hydrogen of a different water molecule is called a ______________________ bond.
Correct Answer
D. Hydrogen
Explanation
The bond formed between the oxygen of one water molecule to the hydrogen of a different water molecule is called a hydrogen bond. This type of bond is a weak attraction between the partial positive charge of the hydrogen atom and the partial negative charge of the oxygen atom in a water molecule. Hydrogen bonds play a crucial role in many biological processes and properties of water, such as its high boiling point and surface tension.
16.
Small insects can walk across the surface of calm water but they do not break the surface of the water and fall under. What property of water to have surface tension?
Correct Answer
B. Cohension
Explanation
The correct answer is cohesion. Cohesion is the property of water that allows it to stick to itself, creating a strong bond between water molecules. This cohesive force is what gives water its surface tension, enabling small insects to walk on the surface without breaking it. Adhesion, on the other hand, refers to the ability of water to stick to other substances, hydrolysis is a chemical reaction involving water, and high specific heat is a different property of water unrelated to surface tension.
17.
Large bodies of water, such as lake and oceans, do not quickly fluctuate in temperature. What is the reason for the phenomenon?
Correct Answer
D. Water has a high heat capacity
Explanation
Large bodies of water, such as lakes and oceans, do not quickly fluctuate in temperature because water has a high heat capacity. This means that water can absorb and store a large amount of heat energy without experiencing significant changes in temperature. As a result, it takes a longer time for large bodies of water to heat up or cool down compared to other substances. This property helps to stabilize the temperature of bodies of water, preventing rapid fluctuations and creating a more stable environment for aquatic life.
18.
Two of the four classes of organic compounds are proteins and nucleic acids. What is the relationship between proteins and nucleic acids?
Correct Answer
D. Nucleic acids contain the instructions to make proteins
Explanation
Proteins and nucleic acids have a relationship where nucleic acids contain the instructions to make proteins. Nucleic acids, such as DNA and RNA, carry the genetic information that determines the sequence of amino acids in proteins. This information is then used by the cell to synthesize proteins through a process called protein synthesis. Therefore, nucleic acids play a crucial role in the production of proteins.
19.
If you were testing the pH of baking soda, you would expected the pH to be
Correct Answer
B. Basic
Explanation
Baking soda, also known as sodium bicarbonate, is an alkaline compound. When dissolved in water, it forms a basic solution. Therefore, when testing the pH of baking soda, it is expected to be basic.
20.
Stomach acid is considered
Correct Answer
D. A strong acid
Explanation
Stomach acid is considered a strong acid because it has a low pH value and can easily donate hydrogen ions. It is primarily composed of hydrochloric acid (HCl), which is a highly corrosive and acidic compound. Stomach acid plays a crucial role in the digestion process by breaking down food and killing harmful bacteria. Its strong acidic nature helps in the breakdown of proteins and activates digestive enzymes.