All Free Biology MCQs with Answers
Every Biology question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
19,844 questions · page 945 of 993
- A. Spirochete
- B. E. coli
- C. Cyanobacteria
- D. Pseudomonas
Explanation: Explanation:This option is correct because pseudomonas is an aerobic bacteria.
Correct answer: Pseudomonas- A. Microscopic bacteria
- B. Anaerobic bacteria
- C. Aerobic bacteria
- D. Methanogenic bacteria
Explanation: Explanation:The giant amoebas obtain energy from methanogenic bacteria which reside inside them, giant amoebas inhabit the mud at the…
Correct answer: Methanogenic bacteria- A. Hyphomicrobium
- B. Haemophilus aquaticus
- C. Haemophillus malariae
- D. Haemophillus infulenzae
Explanation: H. influenzae was the first free-living organism to have its entire genome sequenced.
Correct answer: Haemophillus infulenzae- A. Bacteria
- B. Fungi Cell
- C. Algae
- D. Cortex cells
Explanation: Bacterias have their cell walls made from peptidoglycan which is known to have sugars and amino acids as its constituents.
Correct answer: Bacteria- A. Round
- B. Oval
- C. Spiral
- D. Rod
Explanation: Escherichia coli is an example of rod shaped bacteria, also called Bacilli.
Correct answer: Rod- A. Spirilla
- B. Bacilli
- C. Spirochete
- D. Cocci
Explanation: Bacilli are rod shaped bacteria. Cocci are spherical shaped bacteria. Spirillas are corkscrew shaped bacteria.
Correct answer: Bacilli- A. Plant & Algae
- B. Algae & Fungi
- C. Fungi & Archaea
- D. Bacteria & Archaea
Explanation: Bacteria and Archaea are the groups where cell walls may be absent. While many bacteria have cell walls, there are some bacteria such as…
Correct answer: Bacteria & Archaea- A. 02
- B. 04
- C. 08
- D. 16
Explanation: Sarcina is a genus of bacteria that divides in three planes, resulting in the formation of packets of cells arranged in a cube-like…
Correct answer: 08- A. Cocci
- B. Bacilli
- C. Pleomorphic
- D. Spiral
Explanation: Helicobacter pylori exists as both a helix-shaped form (classified as a curved rod) and a coccoid form.
Correct answer: Pleomorphic- A. Entamoeba histolytica.
- B. Zooflagellates.
- C. Trypanosoma.
- D. Ciliates.
Explanation: African Trypanosomiasis, also known as "sleeping sickness", is caused by microscopic parasites of the species Trypanosoma brucei.
Correct answer: Trypanosoma.- A. Apicomplexans
- B. Annelida
- C. Platyhelminthes
- D. Arthropods
Explanation: Explanation:A large group of parasitic protozoa, some of which causes various diseases such as malaria to humans, are…
Correct answer: Apicomplexans18892. Which of the following is the lowest level of biological organization with respect to others?
- A. Multicellular organisms
- B. Biosphere
- C. Species
- D. Population
Explanation: Option A is correct since Multicellular organism level is the lowest that consist only one organism.Option B is incorrect because…
Correct answer: Multicellular organisms- A. Organ
- B. Organelle
- C. Organ system
- D. Whole organism
Explanation: An organ is defined as a collection of tissues, which combine to form a functional unit within the body, specialized at carrying out a…
Correct answer: Organ18894. Tay-Sach''s disease is due to the presence of an enzyme that is inverted in the catabolism of:
- A. Proteins
- B. Ascorbic Acid
- C. Carbohydrates.
- D. Lipids
Explanation: Explanation:Tay Sach disease is a lipid storage disease. The enzyme absent is involved in catabolism of lipids.
Correct answer: Lipids18895. Fatty acid are the organic compounds containing hydrogen, oxygen and one of the following are:
- A. -COOH
- B. -NH2
- C. Acyl
- D. Sucrose
Explanation: A fatty acid consists of a straight chain of an even number of carbon atoms, with hydrogen atoms along the length of the chain and at one…
Correct answer: -COOH- A. Fatty acids and water
- B. Fatty acids and alcohols
- C. Fatty acids and glucose
- D. Fatty acids and phosphates
Explanation: Acyl-glycerols, such as fats and oils, are esters formed by a condensation reaction between fatty acids and alcohols.
Correct answer: Fatty acids and alcohols- A. Phospholipids
- B. Waxes
- C. Terpenoids
- D. Acylglycerols
Explanation: Cutin in leaves and exoskeleton of insects is made up of wax. Cutin and suberin are complex bio polyesters composed of fatty acids and…
Correct answer: Waxes- A. Triglycerides
- B. Phospholipids
- C. Waxes
- D. Terpenoids
Explanation: Phospholipids are soluble in both water and oil (amphiphilic) because the hydrocarbon tails of two fatty acids are still hydrophobic, but…
Correct answer: Phospholipids- A. Stearic Acid
- B. Palmitic Acid
- C. Butyric Acid
- D. Oleic Acid
Explanation: Oleic acid is a mono-unsaturated omega-9 fatty acid found in various animal and vegetable sources.
Correct answer: Oleic Acid- A. Higher proportion of C-H
- B. Higher proportion of C-O
- C. Higher proportion of Oxygen
- D. Low proportion of C-H bonds
Explanation: C-H bond is a stronger bond than the C-O bond, and since lipids contain a much higher proportion of C-H bonds than carbohydrates (because…
Correct answer: Higher proportion of C-H