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MCQs 1:
Which RNA variant carries the genetic instructions from DNA for protein synthesis?
Topic: Types of RNA and Their Functions
Correct Answer: A) Messenger RNA (mRNA)
Detailed Hint:
- RNA, or Ribonucleic acid, appears in several forms with different functions. The primary types include messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA).
- Messenger RNA plays a crucial role in conveying genetic information from DNA to the ribosome. It carries the DNA instructions for protein assembly.
- Although rRNA and tRNA participate in protein synthesis, they do not directly deliver the DNA's instructions. Ribosomal RNA forms the main structural component of the ribosome, while transfer RNA transports specific amino acids to the ribosome as per the order specified by the mRNA.
- Therefore, the correct answer is A, "Messenger RNA (mRNA)".
MCQs 2:
Which among the following is considered the most straightforward sugar?
Topic: Basic Biochemistry - Sugars
Correct Answer: B) Glucose
Detailed Hint:
- Glucose, starch, sucrose, and glycogen are all carbohydrates, but they vary in complexity.
- Glucose is a monosaccharide, the simplest form of sugar. It serves as the primary fuel for cellular respiration.
- In contrast, starch, sucrose, and glycogen are more complex sugars. Starch and glycogen are polysaccharides, and sucrose is a disaccharide.
- Therefore, the correct answer is B, "Glucose".
MCQs 3:
Which assertion about amino acids is correct?
Topic: Protein Structure and Amino Acids
Correct Answer: A) Amino acids are classified according to the structures and properties of their side chains
Detailed Hint:
- Amino acids are organic compounds that combine to form proteins.
- Although there are hundreds of amino acids, only 20 are used in protein synthesis.
- Amino acids are distinguished by their side chains, which can vary in structure and properties.
- Therefore, the correct answer is A, "Amino acids are classified according to the structures and properties of their side chains".
MCQs 4:
What type of bond is found in the tertiary structure of proteins?
Topic: Protein Structure - Tertiary Structure
Correct Answer: D) All of the above
Detailed Hint:
- The tertiary structure of proteins is the complete three-dimensional structure of a polypeptide chain.
- This structure is stabilized by various types of bonds, including ionic bonds, hydrogen bonds, and disulfide bonds.
- Therefore, the correct answer is D, "All of the above".
MCQs 5:
Which type of RNA constitutes the highest proportion within a cell?
Topic: RNA Types and Roles
Correct Answer: C) rRNA
Detailed Hint:
- Cells contain diverse types of RNA, each serving different functions.
- Messenger RNA (mRNA) carries genetic information from the DNA to the ribosomes where proteins are synthesized.
- Transfer RNA (tRNA) is involved in protein synthesis, bringing amino acids to the ribosomes.
- Ribosomal RNA (rRNA) combines with proteins to form ribosomes, which are the sites of protein synthesis.
- rRNA is the most abundant type of RNA in the cell, contributing up to 80% of the total RNA.
MCQs 6:
Which carbohydrate is the most prevalent in nature?
Topic: Carbohydrates in Nature
Correct Answer: D) Cellulose
Detailed Hint:
- Carbohydrates are organic compounds that occur widely in nature.
- Glycogen is a storage form of glucose in animals.
- Chitin is found in the exoskeleton of arthropods and cell walls of fungi.
- Cellulose is a polysaccharide that forms the cell wall in plants.
- Due to the ubiquity of plants, cellulose is the most abundant carbohydrate in nature.
MCQs 7:
Which biomolecule provides the highest energy yield per gram?
Topic: Nutrient Energy Yields
Correct Answer: B) Fats
Detailed Hint:
- Different biomolecules provide varying levels of energy.
- Carbohydrates typically provide 4 kilocalories per gram, serving as a primary energy source.
- Minerals don't provide energy, but play crucial roles in various bodily functions.
- Proteins, apart from their structural and functional roles, can provide about 4 kilocalories per gram.
- Fats yield about 9 kilocalories per gram, making them the richest source of energy on a per gram basis.
Question 8:
Which of these sequences correctly orders a monosaccharide, a disaccharide, and a polysaccharide?
Topic: Types of Carbohydrates
Correct Answer: B) Glucose; Sucrose; Starch
Detailed Hints:
- Carbohydrates can be classified into three major types: monosaccharides, disaccharides, and polysaccharides.
- Glucose is a simple sugar, or monosaccharide, the most basic form of carbohydrate.
- Sucrose is a disaccharide, composed of two monosaccharides.
- Starch is a polysaccharide, a complex carbohydrate made of many sugar units.
- Hence, the correct order from simplest to most complex is glucose (monosaccharide), sucrose (disaccharide), and starch (polysaccharide).
Question 9:
Which of the following is not an example of a monosaccharide?
Topic: Monosaccharides
Correct Answer: B) Lactose
Detailed Hints:
- Monosaccharides are the simplest form of carbohydrates and cannot be hydrolyzed to smaller carbohydrates.
- Glucose, ribose, and glyceraldehyde are all examples of monosaccharides.
- Lactose, on the other hand, is a disaccharide, which is made up of two monosaccharides.
- Therefore, lactose is not a monosaccharide.
Question 10:
Which amino acid has a side chain (R-group) that consists of a hydrogen atom?
Topic: Amino Acid Structure
Correct Answer: D) Glycine
Detailed Hints:
- Amino acids are organic compounds composed of an amine (-NH2) group, a carboxyl (-COOH) group, and a side chain (R-group).
- The R-group is what differentiates one amino acid from another.
- In the case of glycine, the R-group is simply a hydrogen atom.
- Therefore, the correct answer is D, "Glycine".
Question 11:
What are the products resulting from the hydrolysis of a protein?
Topic: Protein Hydrolysis
Correct Answer: A) Amino acids
Detailed Hints:
- Hydrolysis is a chemical reaction in which a molecule is broken down into smaller units in the presence of water.
- Proteins, upon undergoing hydrolysis, break down into their constituent units.
- These constituent units are known as amino acids, the building blocks of proteins.
- Therefore, when proteins undergo hydrolysis, amino acids are the end products.
Question 12:
In what aspects do DNA and RNA differ?
Topic: Differences between DNA and RNA
Correct Answer: C) In sugars and pyrimidines
Detailed Hints:
- DNA and RNA are both nucleic acids but they have notable differences.
- DNA has a deoxyribose sugar while RNA contains ribose sugar.
- In terms of bases, DNA has thymine whereas RNA has uracil as a pyrimidine base.
- Therefore, DNA and RNA differ in both the sugar component and the type of pyrimidine they contain.
Question 13:
Which type of lipids are composed of simple repeating isoprenoid units?
Topic: Classes of Lipids
Correct Answer: D) Terpenoids
Detailed Hints:
- Lipids are a class of organic compounds, and they can be subdivided into various categories.
- This categorization is based on their chemical composition and structure.
- Terpenoids, also known as isoprenoids, are a diverse class of lipids derived from simple repeating isoprene units.
- As a result, terpenoids are the lipids made up of simple repeating isoprenoid units.
Question 14:
Which is considered the genetic material?
Topic: Genetic Material
Correct Answer: D) DNA
Detailed Hints:
- Genetic material carries the information that determines the traits to be passed on from parents to offspring.
- This material is found in the genes, which are located in DNA.
- Therefore, among the choices given, DNA is the hereditary material.
Question 15:
What type of bonds primarily retain the alpha-helix shape in secondary protein structures?
Topic: Secondary Protein Structure
Correct Answer: C) Hydrogen bonds
Detailed Hints:
- Protein structure is composed of four levels: primary, secondary, tertiary, and quaternary.
- The secondary structure, including the alpha-helix, is maintained primarily by hydrogen bonds.
- These bonds form between the amine and carboxyl groups of the amino acid backbone.
Question 16:
Which among the options is not a disaccharide?
Topic: Types of Carbohydrates
Correct Answer: C) Cellulose
Detailed Hints:
- Carbohydrates can be classified into monosaccharides, disaccharides, and polysaccharides.
- Disaccharides are composed of two monosaccharide units.
- Cellulose, however, is a polysaccharide made up of several hundreds to over ten thousand linked glucose units.
- Hence, cellulose is not a disaccharide but a polysaccharide.
Question 17:
What describes the primary structure of a protein?
Topic: Protein Structure
Correct Answer: B) The count and order of amino acids in the protein molecule
Detailed Hints:
- The structure of a protein can be divided into four levels: primary, secondary, tertiary, and quaternary.
- The primary structure refers to the linear sequence of amino acids in the protein.
- This sequence determines the unique characteristics and function of each protein.
- Thus, the primary structure of a protein is described by the number and sequence of its amino acids.
Question 18:
Despite the existence of approximately 170 amino acids, the majority of proteins are composed of how many types of amino acids?
Topic: Amino Acids in Protein Synthesis
Correct Answer: D) 20
Detailed Hints:
- Proteins, the building blocks of life, are composed of amino acids.
- Although there are around 170 known amino acids, only 20 are used in most protein synthesis in living organisms.
- These 20 types are often referred to as the standard or common amino acids.
- Therefore, despite the broader variety, most proteins are made up of 20 types of amino acids.
Question 19:
In which of the following can peptide bonds be found?
Topic: Peptide Bonds in Proteins
Correct Answer: A) Proteins
Detailed Hints:
- A peptide bond is a covalent bond that forms when the carboxyl group of one molecule reacts with the amino group of another.
- This reaction results in the release of a water molecule.
- Peptide bonds are the backbone of proteins, linking together individual amino acids in a protein's structure.
- Consequently, peptide bonds are present in proteins.
Question 20:
Which statement is incorrect regarding the functions of lipids?
Topic: Functions of Lipids
Correct Answer: D) They act as enzymes
Detailed Hints:
- Lipids, including fats, oils, waxes, cholesterols, and sterols, perform various functions in living organisms.
- They store energy for long-term use, insulate against temperature extremes, and provide waterproofing.
- However, lipids do not act as enzymes; enzymes are proteins that catalyze biochemical reactions.
- Therefore, the statement that lipids act as enzymes is incorrect.
Question 21:
Which disaccharide is primarily contained in the sugar cane stem?
Topic: Disaccharides in Plants
Correct Answer: B) Sucrose
Detailed Hints:
- Disaccharides are a type of carbohydrate composed of two monosaccharide components.
- Different plants contain different types of disaccharides.
- In the case of sugar cane, the stem is rich in sucrose.
- Thus, sucrose is the disaccharide primarily found in sugar cane.
Question 22:
Identify the monosaccharide in the following list:
Topic: Types of Monosaccharides
Correct Answer: B) Fructose
Detailed Hints:
- Monosaccharides are the simplest form of carbohydrates and cannot be further hydrolyzed into smaller carbohydrates.
- Fructose, also known as fruit sugar, is a common monosaccharide found in many plants.
- The other options given, maltose, sucrose, and lactose, are disaccharides, each made up of two monosaccharide units.
- Therefore, fructose is the monosaccharide in this list.