All Free Biology MCQs with Answers

• A. The superior vena cava
• B. Aorta
• C. The inferior vena cava
• D. The four pulmonary veins

Explanation: Yes, the left atrium of the human heart receives four pulmonary veins. The four pulmonary veins are responsible for carrying oxygenated…

• A. Atria ventricular node
• B. Sino-atrial node
• C. Atria ventricular bundles of fibers
• D. Bundle of His

Explanation: The SA node is the heart's natural pacemaker. The SA node consists of a cluster of cells that are situated in the upper part of the walI…

• A. A metabolic disorder
• B. A degenerative disorder
• C. An infectious disorder
• D. A genetic disorder

Explanation: Arteriosclerosis is a degenerative disorder which is the result of continuous process based on degenerative cellular changes affecting…

• A. Liver
• B. Villi
• C. Pancrease
• D. Spleen

Explanation: Therefore, the correct answer is B) Villi, as lacteals are central lymph vessels that are found within the villi of the small intestine.

• A. Inspiration is an active process
• B. Expiration is an active process
• C. Inspiration is a passive process
• D. Both expiration and inspiration are passive processes

Explanation: Inspiration occurs via active contraction of muscles so, is an active process.

• A. Carry blood away from the heart to different organs.
• B. Break up into capillaries which reunite to form a vein.
• C. Carry blood from one visceral organ to another visceral organ.
• D. Supply oxygenated blood to different organs.

Explanation: Arteries are best defined as the vessels which carry blood away from the heart.

• A. Stomach and brain
• B. Ventricle and atrium
• C. Groin and neck
• D. Thyroid gland and adrenal gland

Explanation: Lymph nodes are small, bean-shaped organs that filter lymph fluid, which is a clear fluid that carries waste products and immune cells…

• A. Starch, Proteins, and Fats
• B. Vitamins, Carbohydrates, and Polypeptides
• C. Protein, Cellulose, and Fats
• D. Protein, Starch, and Cellulose

Explanation: Protein, starch, and cellulose enter the stomach undigested and start digestion there.

• A. Sublingual - below the tongue
• B. Sub Mandibular - behind jaws
• C. Parotid - in front of the ear
• D. Lacrimal - above the lateral end of the eye

Explanation: Humans have three paired major salivary glands (parotid, submandibular, and sublingual) While the lacrimal gland is located within the…

• A. Sublingual
• B. Submaxillary
• C. Parotid
• D. Pancreas

Explanation: The gland present at the front of the ear is Parotid gland.

• A. Protein into amino acid
• B. Starch into maltose
• C. Glycogen into glucose
• D. Fats into vitamins

Explanation: Saliva contains an enzyme called salivary amylase, also known as ptyalin, which helps initiate the breakdown of starch (a complex…

• A. Symbiotic Bacteria
• B. Obligate Bacteria
• C. Parasitic Bacteria
• D. Facultative Bacteria

Explanation: [A] Symbiotic bacteria are bacteria that live in a symbiotic relationship with other organisms.

• A. Some of the idiomatic or colloquial expressions found in the play is explained excellently.
• B. Some of the idiomatic or colloquial expressions found in the play are explained excellent.
• C. Some of the idiomatic or colloquial expressions found in the play are explained excellently.
• D. Some of the idiomatic or colloquial expression found in the play ahas explained excellently.

Explanation: Some of the idiomatic or colloquial expressions found in the play are explained excellently.This option is correct as it maintains…

• A. Emil Fischer
• B. Koshland
• C. James Watson and Francis Crick
• D. Rosalind Franklin

Explanation: The Lock and Key model of enzyme action was proposed by Emil Fischer in 1894.

• A. Vitamins
• B. Carbohydrates
• C. Lipids
• D. Proteins

Explanation: Most coenzymes are vitamins or are derived from vitamins. Vitamins are organic compounds that are essential in very small (trace) amounts…

• A. Coenzyme
• B. Blocker
• C. Inhibitor
• D. Cofactor

Explanation: An inhibitor is a chemical substance which can react (in place of substrate) with the enzyme but is not transformed into product(s) and…

• A. Globular proteins
• B. Fibrous proteins
• C. Glycoproteins
• D. Lipoproteins

Explanation: Enzymes are mainly globular proteins - protein molecules where the tertiary structure has given the molecule a generally rounded, ball shape

• A. If the concentration is doubled the rate will become two-fold.
• B. If the concentration is doubled the rate will become one-fold.
• C. This relation is for an unlimited time period with unlimited enzyme concentration.
• D. All of these options are correct.

Explanation: The rate of a chemical reaction is defined as the rate of change in concentration of a reactant or product divided by its coefficient from…

• A. are bacterial enzyme
• B. convert RNA to DNA
• C. hydrolyze protein into amino acids
• D. get mutated for DNA repair

Explanation: Restriction enzyme, also called restriction endonuclease, a protein produced by bacteria that cleaves DNA at specific sites along the…

• A. Slightly acidic
• B. Slightly basic
• C. Highly acidic
• D. Highly basic

Explanation: Enterokinase has an optimal pH of 5.5, which classifies it as slightly acidic.