Biology Molecules Of Life

When a patient is unable to eat or drink, intravenous injection of glucose is used because glucose is readily absorbed by body cells. Intravenous administration allows for direct delivery of glucose into the bloodstream, bypassing the digestive system. This ensures that the patient receives the necessary energy and nutrients from glucose even when they are unable to consume food orally.

Glucose is a monosaccharide because it is a simple sugar that cannot be broken down into smaller sugar molecules. It is the primary source of energy for the body and is found in various foods such as fruits, vegetables, and honey. Sucrose, starch, and glycerol are not monosaccharides. Sucrose is a disaccharide composed of glucose and fructose, starch is a polysaccharide made up of many glucose molecules, and glycerol is a type of alcohol.

The correct base-pairing in DNA is G—C, A—T. This is because in DNA, guanine (G) always pairs with cytosine (C) through three hydrogen bonds, and adenine (A) always pairs with thymine (T) through two hydrogen bonds. This base-pairing pattern is crucial for DNA replication and transcription processes.

A phospholipid molecule consists of a glycerol backbone, two fatty acid chains, and a phosphate group. Deoxyribose, on the other hand, is a sugar molecule found in DNA, not phospholipids. Therefore, deoxyribose is not included in a phospholipid molecule.

Iron is an essential mineral that plays a crucial role in the formation of hemoglobin, the protein responsible for transporting oxygen throughout the body. Hemoglobin is found in red blood cells and binds to oxygen in the lungs, allowing it to be carried to tissues and organs. Without sufficient iron, the body cannot produce enough hemoglobin, leading to a condition called iron deficiency anemia. Therefore, iron is necessary for the proper functioning of organisms by facilitating the formation of hemoglobin.

The given statement that "They are mainly found in the cytoplasm" is incorrect. DNA molecules are primarily found in the nucleus of a cell, not in the cytoplasm. The nucleus is where DNA replication, transcription, and other important cellular processes involving DNA occur. While there is a small amount of DNA present in the cytoplasm, the majority of the DNA is contained within the nucleus.

Glycogen is insoluble because it is a complex carbohydrate made up of many glucose molecules linked together in a highly branched structure. Insoluble means that it does not dissolve in water. In contrast, fructose, sucrose, and maltose are all soluble sugars that can dissolve in water.

Disaccharides are formed by combining two molecules of monosaccharide through condensation. Condensation is a chemical reaction in which two molecules combine to form a larger molecule, with the release of a small molecule such as water. In the case of disaccharides, two monosaccharide molecules join together, and a water molecule is released as a byproduct. This process is essential for the formation of various disaccharides, such as sucrose, lactose, and maltose.

Some organisms do not need oxygen for respiration.

Benedict's test is used to detect the presence of reducing sugars, which are sugars that can donate electrons and reduce other compounds. Glucose, fructose, and lactose are all reducing sugars because they have a free aldehyde or ketone group that can be oxidized. However, sucrose is a non-reducing sugar because it does not have a free aldehyde or ketone group. Therefore, it does not show a positive result in Benedict's test.