1.
The two strands making up DNA
Correct Answer
C. Are held together by hydrogen bonds and Van der Waals forces
Explanation
The correct answer is that the two strands making up DNA are held together by hydrogen bonds and Van der Waals forces. These forces are responsible for the stability and structure of the DNA molecule. Hydrogen bonds form between complementary base pairs (adenine with thymine, and guanine with cytosine), while Van der Waals forces help to stabilize the overall structure of the double helix. These forces are relatively weak individually, but when combined, they provide the necessary strength to hold the two strands of DNA together.
2.
Polysaccharides, lipids and proteins are similar in that they
Correct Answer
B. Are synthesized from monomers by the process of dehydration reactions
Explanation
Polysaccharides, lipids, and proteins are all macromolecules that are synthesized from smaller subunits called monomers. The process by which these macromolecules are formed is called dehydration reactions, where a water molecule is removed to link the monomers together. This process of dehydration reactions is common for the synthesis of all three types of macromolecules. Therefore, the correct answer is that polysaccharides, lipids, and proteins are synthesized from monomers by the process of dehydration reactions.
3.
All of the following molecules are proteins except
Correct Answer
E. Cellulose
Explanation
Cellulose is not a protein because it is a complex carbohydrate made up of glucose molecules linked together. Hemoglobin, antibodies, collagen, and lysozomes are all proteins. Hemoglobin is a protein found in red blood cells that transports oxygen. Antibodies are proteins produced by the immune system to help fight off infections. Collagen is a protein that provides structure and support to tissues such as skin, tendons, and bones. Lysozomes are organelles within cells that contain enzymes for breaking down waste materials.
4.
Nucleotides are to _________________, as _________________ are to proteins.
Correct Answer
A. Nucleic acids/amino acids
Explanation
Nucleotides are the building blocks of nucleic acids, which include DNA and RNA. Similarly, amino acids are the building blocks of proteins. Both nucleic acids and proteins are essential biomolecules involved in various biological processes.
5.
To turn a "nucleoside" into a "nucleotide" it would be necessary to
Correct Answer
D. Add pHospHate to the nucleoside
Explanation
To turn a "nucleoside" into a "nucleotide", it would be necessary to add a phosphate group to the nucleoside. This is because a nucleotide is composed of a nucleoside (which consists of a nitrogenous base and a sugar) and one or more phosphate groups. The addition of the phosphate group forms the phosphodiester bond, which links the nucleoside to the phosphate group and converts it into a nucleotide.
6.
If one strand of a DNA molecule has the sequence ATTGCA, the complementary strand is
Correct Answer
A. TAACGT
Explanation
The complementary strand of DNA is formed by pairing nucleotides with their complementary bases. In DNA, adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G). Therefore, to find the complementary strand, we need to replace each base with its complementary base. In the given sequence ATTGCA, A pairs with T, T pairs with A, G pairs with C, and C pairs with G. So, the complementary strand is TAACGT.
7.
The structural feature that allows DNA to replicate itself is
Correct Answer
B. Complementary base pairing
Explanation
Complementary base pairing is the structural feature that allows DNA to replicate itself. This refers to the specific pairing of nucleotide bases, where adenine (A) always pairs with thymine (T), and cytosine (C) always pairs with guanine (G). This base pairing allows for the accurate replication of DNA during cell division, as each strand serves as a template for the synthesis of a new complementary strand. This ensures that the genetic information is faithfully passed on to the next generation.
8.
Dehydration reactions are used in the forming of
Correct Answer
E. All three are correct
Explanation
Dehydration reactions are used in the forming of triglycerides, polysaccharides, and proteins. These reactions involve the removal of water molecules to create chemical bonds between monomers, resulting in the formation of larger molecules. Triglycerides are formed through the dehydration synthesis of three fatty acid molecules and one glycerol molecule. Polysaccharides, such as starch and cellulose, are formed through the dehydration synthesis of multiple sugar molecules. Proteins are formed through the dehydration synthesis of amino acid molecules. Therefore, all three options are correct as dehydration reactions play a role in the formation of triglycerides, polysaccharides, and proteins.
9.
Which of the following illustrates hydrolysis?
Correct Answer
D. Fat forming glycerol and fatty acids using water
Explanation
The correct answer is "fat forming glycerol and fatty acids using water". Hydrolysis is a chemical reaction in which a compound is broken down into its components by the addition of water. In this case, the fat molecule is broken down into its components, glycerol and fatty acids, with the help of water.
10.
All of the following are carbohydrates except
Correct Answer
C. Hemoglobin
Explanation
Hemoglobin is not a carbohydrate because it is a protein. Carbohydrates are organic compounds that consist of carbon, hydrogen, and oxygen atoms, while proteins are made up of amino acids. Hemoglobin is a protein found in red blood cells that is responsible for carrying oxygen throughout the body. Therefore, it does not fit the definition of a carbohydrate.