Explanation

• Succinate is oxidized to fumarate by the enzyme succinate dehydrogenase.
• During this reaction, FAD accepts hydrogen and electrons and is reduced to FADH₂.
• Succinate dehydrogenase is also known as Complex II of the electron transport chain.
• FADH₂ carries high-energy electrons to the electron transport chain, helping produce ATP.

Last verified on 31-10-2026

Explanation

• Calcium ions (Ca²⁺) act as important chemical signals in many cellular processes.
• Calcium entry into pancreatic beta cells helps trigger insulin secretion.
• Calcium influx into nerve endings triggers the release of neurotransmitters into the synaptic cleft.
• Calcium enables muscle contraction by interacting with regulatory proteins in muscle cells.
• Calcium also contributes to the electrical activity and contraction of the heart.

Last verified on 31-10-2026

Explanation

• The tibia is the larger, medial bone of the lower leg, commonly called the shinbone.

Additional information:

• The bones that are part of the human hind limb (the lower limb or leg) include:

• Femur (Thigh bone)

• Patella (Kneecap)

• Tibia (Shin bone)

• Fibula (Calf bone)

• Tarsals (Ankle bones)

• Metatarsals (Foot bones)

• Phalanges (Toe bones)

Last verified on 31-10-2026

Explanation

• Felix Bernstein explained the ABO blood group system in 1924.
• ABO blood groups are controlled by three alleles: IA, IB, and i.
• IA and IB are codominant, both are dominant over i.

Last verified on 31-10-2026

Explanation

• Insulin is a peptide hormone produced by the beta cells of the pancreas.
• Mature insulin consists of two polypeptide chains: A chain (21 amino acids) and B chain (30 amino acids).
• These two chains are held together by two interchain disulphide bonds.
• One additional disulphide bond is present within the A chain.
• Disulphide bonds help maintain the proper three-dimensional structure and biological activity of insulin.

Last verified on 31-10-2026

Explanation

• Both plant and animal cells are eukaryotic cells and contain a nucleus.
• Both contain cytoplasm, where many important cellular chemical reactions take place.
• Both contain mitochondria, which produce ATP through cellular respiration.
• Chloroplasts are present in photosynthetic plant cells but are absent in animal cells.

Last verified on 31-10-2026

Explanation

• Restriction enzymes are also called molecular scissors because they cut DNA at specific recognition sequences.
• They recognize particular short DNA sequences, often 4–8 base pairs long.
• These enzymes may produce sticky ends or blunt ends after cutting DNA.
• They are widely used in genetic engineering, recombinant DNA technology, and gene cloning.
• Example: EcoRI is a restriction enzyme that recognizes the sequence GAATTC.

Last verified on 31-10-2026

Explanation

• Deamination is the process of removing the amino group (–NH₂) from amino acids.
• This process produces ammonia, which is toxic to the body.
• The liver converts ammonia into urea through the urea cycle.
• Urea is transported through the blood to the kidneys and eliminated in urine.
• The remaining carbon skeleton can be used for energy production or converted into glucose or ketone bodies.

Last verified on 31-10-2026

Explanation

• The electrical impulse originates in the SA node, the natural pacemaker of the heart.
• It takes approximately 0.03 seconds for the impulse to travel from the SA node to the AV node.
• The AV node itself produces a delay of about 0.09 seconds.
• An additional delay of approximately 0.04 seconds occurs in the penetrating part of the AV bundle (Bundle of His).
• Total delay = 0.03 + 0.09 + 0.04 = 0.16 seconds, commonly rounded to approximately 0.15 seconds.

Last verified on 31-10-2026

Explanation

• Lithonephritis refers to inflammation of the kidney associated with kidney stones.
• Kidney stones are also called renal calculi or nephroliths.
• Stones may irritate or obstruct the urinary tract, causing pain, bleeding, and sometimes infection.
• Nephritis is a general term for inflammation of the kidneys.

Last verified on 31-10-2026