The technique of using radioactive probes to detect specific DNA sequences on a membrane is: MCQ with Answer and Explanation

Explanation:
Smooth endoplasmic reticulum (SER) lacks ribosomes and is the site of lipid synthesis, including phospholipids and steroids. It also detoxifies drugs and poisons. Rough ER synthesizes proteins, Golgi modifies and packages molecules, lysosomes degrade waste. SER is abundant in cells producing steroid hormones.

Explanation:
Iron (Fe²⁺) is the central atom of heme in hemoglobin and myoglobin, essential for oxygen transport. Deficiency leads to microcytic hypochromic anemia. Good sources: liver, meat, leafy greens.

Explanation:
The kidneys are the primary excretory organs, filtering blood through nephrons to remove waste products and excess water, forming urine. The liver is a multifunctional organ that produces bile, which is stored in the gall bladder and released into the small intestine to emulsify fats, aiding in their digestion. The spleen is a lymphoid organ involved in filtering blood and immune responses; it does not produce digestive enzymes (the pancreas does). Thus, statements 1 and 2 are correct.