Prepare for General Aptitude Tests with this free Biology MCQs practice quiz. Attempt every question, submit the test and review the correct answers with explanations.
About This Biology Practice Quiz
- Questions: 25
- Time: 25 minutes
- Difficulty: Mixed
- Topic: Biological Molecules
How to Attempt the Quiz
Select one answer for each question, use the question palette to move between questions, mark difficult questions for review and submit the test to see your score.
Interactive Practice Test
Biological Molecules Quiz – 1
25 questions • 25 minutes
25:00
Question 1 of 25Biological Molecules
Which property of water prevents a cell's protoplasm from sudden thermal changes?
Explanation: Water's high specific heat allows it to work as a temperature stabilizer for organisms, protecting protoplasm against sudden thermal charges.
Question 2 of 25Biological Molecules
Which group of proteins includes enzymes, antibodies, and hormones?
Explanation: Globular proteins are described as being functional and include examples like enzymes, antibodies, hormones, and hemoglobin.
Question 3 of 25Biological Molecules
Which type of linkage is found between the units of carbohydrates like oligosaccharides and polysaccharides?
Explanation: Table 1.1 explicitly lists the glycoside linkage (or glycosidic linkage) as the unit connector for carbohydrates like oligosaccharides and polysaccharides.
Question 4 of 25Biological Molecules
Why is water described as a 'Dipole'?
Explanation: Water is called a Dipole because of the separation of electrical charges (partial negative on oxygen and partial positive on hydrogen).
Question 5 of 25Biological Molecules
Which class of lipids is composed of repeating isoprenoid units (C5H8)?
Explanation: Terpenoids are defined as a large and important class of lipids made up of isoprenoid units (C5H8), including terpenes and steroids.
Question 6 of 25Biological Molecules
Which of the following describes the secondary structure of fibrous proteins like silk and keratin?
Explanation: Fibrous proteins are described as long fibers where secondary protein (spiral) chains intertwine with each other, making them insoluble and elastic.
Question 7 of 25Biological Molecules
What happens to the density of water as its temperature drops from 4°C down to 0°C?
Explanation: Water shows different behavior below 4°C; it expands, which decreases its density so that at 0°C it is lighter than liquid water.
Question 8 of 25Biological Molecules
In the breakdown of proteins, what is the intermediate stage between a polypeptide and a peptide?
Explanation: Section 1.4.1.1 states that a protein chain can be broken into small chains of more than 10 amino acids called peptone, which then breaks into peptides.
Question 9 of 25Biological Molecules
What is the unit and linkage of RNA according to Table 1.1?
Explanation: Table 1.1 lists Ribonucleotides as the units and Phosphoester linkages for RNA.
Question 10 of 25Biological Molecules
What happens to the structure of Cellulose as it condenses?
Explanation: The text states that straight chains of cellulose become spirally coiled and condensed to form tubes, which form the cell-wall of plant cells.
Question 11 of 25Biological Molecules
What property of water explains why oil drops coalesce into a large droplet in an aqueous environment?
Explanation: Hydrophobic exclusion is the tendency of water to coalesce oil drops into large droplets because water molecules form hydrogen bonds with themselves, excluding the non-polar oil.
Question 12 of 25Biological Molecules
Which protein is found in the shells of mollusks and crustaceans as a composite material?
Explanation: The text mentions that Chitin is found with CaCO3 in the shells of mollusks and crustaceans, making the material much harder and stiffer.
Question 13 of 25Biological Molecules
What term is used to describe the remaining mass of a cell after all water has been evaporated?
Explanation: The text explains that if the water is evaporated from a cell, the remaining mass is called the 'Dry Weight' of the cell, consisting of organic molecules.
Question 14 of 25Biological Molecules
Which part of a phospholipid molecule is considered 'hydrophilic' or 'water-loving'?
Explanation: Phospholipids have two ends: the fatty acid non-polar 'hydrophobic' part and the phosphate/choline 'hydrophilic' part that attracts water.
Question 15 of 25Biological Molecules
Why does water have a high specific heat?
Explanation: The text states the specific heat of water is high due to its polar nature and hydrogen bonding between the molecules.
Question 16 of 25Biological Molecules
Which lipid group acts as a protective coating on stems, leaves, and animal skin?
Explanation: Waxes are described as simple lipids that found as protective coating on stem, stalks, leaves, petals, fruits skin, animal skin, fur and feathers.
Question 17 of 25Biological Molecules
How many amino acids are considered the basic building blocks for all proteins from viruses to humans?
Explanation: The text states there are twenty basic amino acids which constitute each type of protein found in organisms from viruses to humans.
Question 18 of 25Biological Molecules
Which disaccharide is composed of two glucose units?
Explanation: Fig 1.1 on page 9 shows the formation of Maltose from the combination of two Glucose units.
Question 19 of 25Biological Molecules
Which of the following is a classic example of a triose sugar mentioned in the text?
Explanation: Table 1.3 lists Glycerose (Glyceraldehyde) and Dihydroxy acetone as examples of Triose sugars, which contain three carbon atoms.
Question 20 of 25Biological Molecules
Which molecule provides a cooling effect during transpiration or perspiration?
Explanation: The section on high heat of vaporization explains that water provides a cooling effect when it evaporates during transpiration or perspiration.
Question 21 of 25Biological Molecules
In the steroid skeleton, how many rings are hexagonal and how many are pentagonal?
Explanation: The text describes the steroid nucleus as having four attached rings, where three are hexagonal and one is pentagonal in shape.
Question 22 of 25Biological Molecules
In the context of disaccharides, what is the chemical reason a sugar is classified as 'non-reducing'?
Explanation: Non-reducing sugars (like sucrose) are unable to be oxidized because they lack free aldehyde or ketone groups.
Question 23 of 25Biological Molecules
Why is water considered an 'amphoteric' molecule?
Explanation: The chapter states that due to its ionization into H+ and OH-, water may behave as an acid or a base, meaning it is amphoteric in nature.
Question 24 of 25Biological Molecules
What is the role of 'Sclera protein' according to the list of structural proteins?
Explanation: Table 1.4 lists Sclera protein and notes it 'Include Keratin, collage, elastin and fibrin'.
Question 25 of 25Biological Molecules
What is the chemical composition of a mammalian cell regarding DNA and RNA percentages?
Explanation: Table 1.2 lists the composition of a Mammalian cell as DNA (0.25%) and RNA (1.10%).