Explanation

Explanation

• All standard amino acids have a central carbon called the alpha carbon (α-carbon).
• The alpha carbon is attached to four groups: an amino group (–NH₂), a carboxyl group (–COOH), a hydrogen atom, and a variable R group.
• The R group determines the chemical properties and identity of each amino acid.
• There are 20 standard amino acids commonly used to build proteins.

Last verified on 31-10-2026

Explanation

• Glucose is filtered from the blood at the glomerulus.
• In a healthy person, almost all filtered glucose is reabsorbed into the blood in the proximal convoluted tubule (PCT).
• Glucose may appear in urine when blood glucose exceeds the renal threshold, commonly associated with diabetes mellitus.

Last verified on 31-10-2026

Explanation

• ADH (Antidiuretic Hormone) is produced by the hypothalamus and released by the posterior pituitary gland.
• ADH increases water reabsorption in the kidney collecting ducts, helping the body conserve water.
• Very low ADH causes less water reabsorption, resulting in a large volume of dilute urine.
• This condition is called central diabetes insipidus.
• Excessive thirst and dehydration may also occur due to increased water loss.

Last verified on 31-10-2026

Explanation

• Amphitrichous bacteria have flagella at both ends of the cell.
• Flagella are whip-like structures that help bacteria move.

Last verified on 31-10-2026

Explanation

• Lipids contain a higher proportion of carbon-hydrogen (C–H) bonds.
• These bonds store considerable chemical energy, which is released during oxidation.
• Lipids provide approximately 9 kcal (37 kJ) per gram.

Additional information:

• Carbohydrates provide approximately 4 kcal (17 kJ) per gram.

Last verified on 31-10-2026

Explanation

• Protein synthesis is performed by ribosomes, not by the cell membrane.
• The cell membrane controls the movement of substances into and out of the cell.
• It helps in cellular communication through membrane receptors.
• It protects the cytoplasm and separates the internal contents of the cell from the external environment.
• Ribosomes may be free in the cytoplasm or attached to the rough endoplasmic reticulum.

Last verified on 31-10-2026

Explanation

• Natural passive immunity occurs when antibodies are transferred naturally from mother to fetus through the placenta.
• The main antibodies transferred across the placenta are IgG antibodies.
• These antibodies provide temporary protection to the newborn against certain infections.
• The baby receives protection without producing these antibodies through its own immune system.
• Breast milk, particularly colostrum, also provides antibodies (mainly IgA) to the newborn.

Last verified on 31-10-2026

Explanation

• The vertebral column, also called the backbone or spine, is part of the axial skeleton.
• The axial skeleton forms the central supporting axis of the human body.
• It includes the skull, vertebral column, ribs, and sternum.

Additional information:

• The human vertebral column usually consists of 33 vertebrae: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral (fused), and 4 coccygeal (usually fused).

Last verified on 31-10-2026

Explanation

• Facilitated diffusion uses membrane transport proteins, such as channel or carrier proteins, to move substances from higher to lower concentration.
• This process is a type of passive transport, so it does not require cellular energy (ATP).

Additional information:

• Active transport moves substances against their concentration gradient and usually requires energy.
• Simple diffusion occurs directly through the membrane without transport proteins.

Last verified on 27-10-2026