The movement of molecules from a region of higher concentration to a region of lower concentration without a membrane is: MCQ with Answer and Explanation
The movement of molecules from a region of higher concentration to a region of lower concentration without a membrane is:
A. Osmosis
B. Simple diffusion
C. Facilitated diffusion
D. Active transport
Answer: Option B
Solution (By JKExamLibrary)
Simple diffusion is the passive movement of molecules (e.g., O₂, CO₂) from high to low concentration without the need for a membrane protein or energy. Osmosis specifically refers to water movement across a semipermeable membrane. Facilitated diffusion uses channel or carrier proteins but no energy. Active transport requires energy (ATP).
Explanation:
Analogous organs are structures that perform similar functions but have different anatomical structures and evolutionary origins. The wings of a bird (modified forelimbs with bones and feathers) and the wings of an insect (membranous extensions of the exoskeleton) both evolved for flight but are not derived from a common winged ancestor. This is an example of convergent evolution.
In the process of urine formation, the step that involves selective reabsorption of glucose, amino acids, and water from the filtrate back into the blood is:
Explanation:
Tubular reabsorption occurs mainly in the proximal convoluted tubule, where essential substances like glucose, amino acids, and most water are reabsorbed into peritubular capillaries via active and passive transport. Glomerular filtration/ultrafiltration is the initial passive filtration of blood. Tubular secretion adds substances like H⁺ and K⁺ to filtrate.
Explanation:
Nitrification is a two-step process in the nitrogen cycle where ammonia is oxidized to nitrates. First, ammonia (NH3) is converted to nitrites (NO2-) by bacteria like Nitrosomonas. Then, nitrites are converted to nitrates (NO3-) by bacteria like Nitrobacter. Nitrates are the primary form of nitrogen absorbed by plants. Denitrification is the reverse process, converting nitrates back to nitrogen gas.
No comments yet. Be the first to start the discussion!