Is glucose the major source of energy for cells?

Answer 1

No. Most organisms can use various compounds for energy. First of all there are many sugars that can be used for energy such as glucose, galactose, fructose etc... Proteins are another source of energy although less efficient at storing energy than sugars. Of course when the body has an excess of glucose, the energy reserves are stored as lipids (fat) which can later be used to harvest energy.

Answer 2

Glucose isn't an instant source of energy but if you are talking about in your body the reason it is quck to act is because glucose is what your body uses to create energy along with oxygen so your body doesn't need to convert the glucose to anything else.

Glucose is a small enough molecule that it can be absorbed through the lining of the stomach. Bigger molecules are absorbed through the lining of the intestine, which would take longer because the sugars have to pass through the stomach to get there.

Glucose is also the prefered respiritory substrate. Glucose for respiration comes from 3 different places; the diet, the breakdown of glycogen (glycogenolysis), and new glucose being made from souces other than carbohydrates like glycerol and amino acids (gluconeogenesis).

When sugars like maltose and lactose (maltose and lactose are disaccharides which are made up 2 monosaccharides, glucose is a monosaccharide) are injested they have to be broken down before they are used to 'fuel' respiration. Glucose does not have to be broken down so it is availiable to 'fuel' respiration from when it is absorbed from the stomach. Glycogenolysis and gluconeogenesis also take more time than the absorption of glucose straight from the stomach.

Respiration uses the glucose and oxygen to convert ADP (adenosine diphosphate) and an inorganic phosphate to ATP (adenosine triphosphate). It does this by making a bond between ADP and the phosphate. Energy is required to make bonds, and it is released when the bond is broken. Respiration uses the glucose to provide the energy to make this bond, producing ATP. This ATP is then broken down to provide energy to do work, like contraction of muscles.

I know this doesn't seem instant, but it does happen pretty quickly.

Answer 3

When referring to cells in a human body, it depends on where those cells are, for instance the heart runs off of the TCA cycle, eating away only at fats, where the brain runs solely on glucose and ketone bodies.

Glucose is not necessarily the only major sources of energy, although is is very important. Energy from fat cells is also a major energy source.

Answer 4

Yes. During the process of aerobic respiration as many as 38 molecules of ATP are produced for every molecule of glucose that is utilized. The aerobic respiration process breaks down a single glucose molecule to yield 38 units of the energy storing it in ATP molecules.

Answer 5

Yes, glucose is the main source of energy in cellular respiration. It is the substrate molecule for glycolysis, and any other complex sugars are broken down to glucose to start the process. Besides this, fats are also sources but in times of high energy need, or when glucose is not readily available. At those time, acetyl-CoA, a break-down product of fatty acids, becomes the prime energy source.

Answer 6

because releasing all the energy in glucose would waste it and heat up the organism

Answer 7

Yes, glucose is the main source of energy during cellular respiration. Cellular respiration is brought about by glycolysis and Kreb's cycle to release energy, CO2 and water.