Biology Test 288

The organism that depends on dead and decaying organic matter is called a saprophyte. Saprophytes are a type of decomposer that obtain their nutrients and energy by breaking down dead plant or animal material. They play a vital role in the ecosystem by recycling nutrients and returning them to the environment for other organisms to use. 

Example: Moulds, Mushroom etc. 

Autotrophs, on the other hand, are organisms that can produce their own food using inorganic substances and an external energy source, such as sunlight. They convert carbon dioxide and water into organic compounds through the process of photosynthesis (in plants) or chemosynthesis (in some bacteria). Autotrophs do not rely on dead organic matter for their nutrition.

Carnivores are organisms that primarily consume the flesh of other animals. They obtain their energy and nutrients by hunting and feeding on other living organisms, rather than on dead organic matter.

Herbivores are organisms that primarily consume plant material. They obtain their energy and nutrients by feeding on plants or plant parts. Herbivores generally do not depend directly on dead and decaying organic matter as their main source of nutrition.

Energy is a fundamental requirement for all living organisms to carry out their various biological processes. Within cells, energy is stored and transferred in different molecules. The molecule that primarily stores and transfers energy in living systems is called adenosine triphosphate, or ATP.

A: FAD (Flavin adenine dinucleotide) is another molecule involved in energy transfer within cells, but it is not the primary molecule for energy storage.

B: NADH (Nicotinamide adenine dinucleotide) is an important molecule in cellular respiration, which is involved in the transfer of electrons and hydrogen ions during energy production. While it plays a role in energy transfer, it is not the primary molecule for energy storage.

D: ADP (Adenosine diphosphate) is the molecule that forms when one phosphate group is removed from ATP. It is the "lower energy" form of ATP and can be converted back into ATP by adding a phosphate group. However, it is not the primary molecule for energy storage.

The TCA cycle begins with a condensation reaction. In this step, an acetyl group, derived from the breakdown of glucose or fatty acids, combines with oxaloacetic acid (OAA), a four-carbon molecule, in the presence of water. This condensation reaction forms a six-carbon compound called citric acid or citrate.

The complete reaction is as follows:

Acetyl-CoA + OAA + H₂O → Citric Acid (Citrate)

The condensation step is significant because it marks the entry of the acetyl group into the TCA cycle and the beginning of a series of enzymatic reactions that ultimately lead to the release of energy and the regeneration of OAA.

During anaerobic respiration, less energy is produced compared to aerobic respiration because incomplete oxidation of glucose occurs. Anaerobic respiration occurs in the absence of oxygen, typically in situations where oxygen is not readily available or during strenuous exercise when oxygen demand exceeds supply.

The two molecules of pyruvic acid (produced from one glucose molecule during glycolysis). The acetyl CoA then enters a cyclic pathway, tricarboxylic acid cycle, more commonly called as Krebs’ cycle. Thus, acetyl-CoA interconnecting between two cyclic pathways.

This is the correct option as this is not a function of kidneys. Kidneys do not absorb nitrogenous wastes. They remove nitrogenous wastes such as urea and uric acid from the blood.

This is the correct option. In renal tubular acidosis, a person is unable to secrete adequate quantities of hydrogen ions due to which large amounts of sodium bicarbonate are continuously lost into the urine.

Sweat does not contain uric acid.

Maximum reabsorption of useful substances from glomerular filtrate occurs in proximal convoluted tubule (PCT). PCT is lined by a simple cuboidal brush border epithelium which increases the surface area for reabsorption. Nearly all of the essential nutrients, and 70-80 percent of electrolytes and water are reabsorbed by this segment.

The proximal convoluted tubule is lined by a simple cuboidal brush border epithelium, which increases the surface area for reabsorption. Simple cuboidal epithelia are found on the surface of the lines of nephrons, the walls of the renal tubules, and parts of the eye and thyroid.