1.
Glucose, the primary source of energy for a cell, is a type of
Correct Answer
D. Monosaccharide
Explanation
Glucose is a monosaccharide, which means it is a simple sugar consisting of a single sugar unit. It is the primary source of energy for cells as it can be easily broken down through cellular respiration to release energy. Polypeptides are chains of amino acids and not sugars, polysaccharides are complex carbohydrates made up of multiple sugar units, and disaccharides are composed of two sugar units. Therefore, the correct answer is monosaccharide.
2.
The atoms that make up carbohydrates are
Correct Answer
A. C, H and O
Explanation
Carbohydrates are organic compounds composed of carbon (C), hydrogen (H), and oxygen (O) atoms. These elements combine in specific ratios to form the basic structure of carbohydrates. While nitrogen (N) is present in other biomolecules like proteins, it is not a component of carbohydrates. Therefore, the correct answer is C, H, and O.
3.
Lipids are
Correct Answer
D. All of these
Explanation
Lipids are a diverse group of molecules that are hydrophobic, meaning they do not dissolve in water. They are also important for energy storage in the body. Therefore, the correct answer is "all of these" as lipids are both hydrophobic and important for energy storage.
4.
Which of the following is not a function in which lipids play an important role?
Correct Answer
A. Vision
Explanation
Lipids play an important role in vision because they are a major component of the retina and help in the absorption and transportation of light. They are involved in the synthesis of visual pigments and contribute to the structure and function of the photoreceptor cells. Therefore, vision is a function in which lipids play an important role.
5.
You have isolated an unidentified liquid from a sample of beans. You add the liquid to a beaker of water and shake vigorously. After a few minutes, the water and the other liquid separate into two layers. To which class of large biological molecules does the unknown liquid most likely belong?
Correct Answer
B. Lipids
Explanation
The correct answer is lipids. Lipids are a class of large biological molecules that are known to be insoluble in water. When the unidentified liquid is added to water and the two substances separate into two layers, it suggests that the liquid is insoluble in water, which is a characteristic of lipids.
6.
Amino acids are the monomers that join together to form
Correct Answer
C. Proteins
Explanation
Amino acids are the building blocks or monomers that combine through peptide bonds to form proteins. Proteins are large, complex molecules that play a crucial role in various biological processes. They are involved in structural support, enzymatic reactions, transportation, and communication within cells. Therefore, it is correct to say that amino acids join together to form proteins.
7.
Enzymes are
Correct Answer
D. Proteins
Explanation
Enzymes are proteins because they are biological catalysts that speed up chemical reactions in living organisms. Proteins are made up of amino acids, and enzymes are a specific type of protein that have a unique three-dimensional structure that allows them to bind to specific molecules and facilitate reactions. Enzymes play crucial roles in various biological processes, such as digestion, metabolism, and DNA replication. They are highly specific and can be regulated to control the rate of reactions in cells. Therefore, the correct answer is proteins.
8.
Which description BEST fits the class of molecules known as nucleotides?
Correct Answer
D. A nitrogenous base, a pHospHate group, and a pentose sugar
Explanation
Nucleotides are molecules that consist of a nitrogenous base, a phosphate group, and a pentose sugar. The nitrogenous base can be either a purine (adenine, guanine) or a pyrimidine (cytosine, thymine, uracil). The phosphate group is responsible for the acidic properties of nucleotides, while the pentose sugar provides the backbone for the molecule. Therefore, the description that BEST fits nucleotides is "a nitrogenous base, a phosphate group, and a pentose sugar."
9.
Which of the following BEST describes the flow of genetic information in eukaryotic cells?
Correct Answer
B. DNA->RNA->proteins
Explanation
In eukaryotic cells, the flow of genetic information starts with DNA, which contains the genetic code. This DNA is then transcribed into RNA through a process called transcription. The RNA molecule carries the genetic information from the DNA to the ribosomes, where it is translated into proteins through a process called translation. Therefore, the correct flow of genetic information in eukaryotic cells is DNA->RNA->proteins.
10.
Hemoglobin is a globular protein composed of four polypeptide chains and their associated heme groups. Each polypeptide chain is a string of amino acids. What holds the amino acids together?
Correct Answer
D. Peptide bonds
Explanation
Peptide bonds hold the amino acids together in a polypeptide chain. A peptide bond is a covalent bond formed between the carboxyl group of one amino acid and the amino group of another amino acid. This bond is formed through a dehydration synthesis reaction, where a water molecule is eliminated. The repeated formation of peptide bonds between amino acids results in the formation of a polypeptide chain, which is a primary structure of proteins like hemoglobin.
11.
Which molecules are components of an RNA nucleotide?
Correct Answer
B. pHospHate, ribose, uracil
Explanation
RNA nucleotides are composed of three main components: a phosphate group, a sugar molecule called ribose, and a nitrogenous base called uracil. Phosphate provides the backbone structure of the nucleotide, ribose is the sugar molecule that forms the central part of the nucleotide, and uracil is one of the four nitrogenous bases found in RNA molecules. Thymine is found in DNA nucleotides, not RNA nucleotides. Therefore, the correct answer is phosphate, ribose, uracil.
12.
Which organic molecules store the genetic information of a cell?
Correct Answer
D. Nucleic acids
Explanation
Nucleic acids store the genetic information of a cell. This is because nucleic acids, specifically DNA and RNA, contain the instructions for the development, functioning, and reproduction of all living organisms. DNA carries the genetic code that determines an organism's traits, while RNA plays a crucial role in protein synthesis. Carbohydrates, proteins, and lipids are important biomolecules, but they do not store genetic information.
13.
What is the major purpose of DNA?
Correct Answer
C. To store genetic information and serve as template to make RNA
Explanation
The major purpose of DNA is to store genetic information and serve as a template to make RNA. DNA contains the instructions for building and maintaining an organism, including the production of proteins. It serves as a blueprint for the synthesis of RNA molecules, which are then used to produce proteins through a process called transcription and translation. DNA also carries and passes on genetic information from one generation to the next, allowing for the transmission of traits and characteristics.