Cell Structure 3. Membrane Structure 4. Membrane Transport 5. Origin of Cells 6. Cell Division 2: Molecular Biology 1. Metabolic Molecules 2. Water 3. Protein 5.
Enzymes 6. Cell Respiration 9. Photosynthesis 3: Genetics 1. Genes 2. Chromosomes 3. Meiosis 4. Inheritance 5. Genetic Modification 4: Ecology 1. Energy Flow 3. Carbon Cycling 4.
In some cases, they act as antioxidants in your cells too. Vitamin C, Vitamin E, and the precursor to Vitamin A are all antioxidant compounds that you need in your diet.
Vitamin C is mostly needed to maintain connective tissues while Vitamin A is mostly needed by the light-sensitive cells in the back of your eye. Both Vitamin A and C may also act as antioxidants in your cells, however. Vitamin E is an effective antioxidant in your cells and those of plants.
You can gain whatever antioxidant benefits these compounds provide by including plenty of fresh fruits and vegetables in your diet. You can also get them from supplements vitamin pills but take care. Both Vitamin A and E are toxic at high dosages.
Now that you understand how cells get energy from the sun photosynthesis by green plant cells or from food non-photosynthetic cells, including yours , let's discuss energy flow through a multi-celled organism, which is an assemblage of many cells working together. Let's use your body as an example.
In a multi-celled organism, cells are organized into tissues. Tissue are combined into organs and organs cooperate in "organ systems". One of these is the digestive system of your body.
The digestive system includes the digestive tract, a pathway through your body that is taken by the food you eat. The digestive tract includes mouth, esophagus, stomach, and intestines small and large. The liver and pancreas are part of the digestive system also.
The liver stores blood sugar glucose as glycogen animal starch and produces bile salts for the digestion of fats in the small intestine. The pancreas secretes digestive enzymes and bicarbonate buffer to neutralize stomach acid into the small intestine.
The pancreas also releases insulin and glucagon into the blood. These are two hormones that act to maintain a stable concentration of glucose in the blood. Adipose tissue can also be considered part of the digestive system. It stores fat for later conversion to glucose, if necessary.
All of your cells need glucose and oxygen to perform aerobic respiration. Oxygen is the final electron acceptor at the end of the electron transport chain of aerobic respiration. In the absence of oxygen, only a few ATP are produced from glucose. In the presence of oxygen, many more ATP are made. However, some anaerobic organisms that evolved before the atmosphere contained oxygen have survived to the present.
Therefore, anaerobic respiration , which takes place without oxygen, must also have advantages. A major advantage of aerobic respiration is the amount of energy it releases. Without oxygen, organisms can split glucose into just two molecules of pyruvate. This releases only enough energy to make two ATP molecules. With oxygen, organisms can break down glucose all the way to carbon dioxide.
This releases enough energy to produce up to 38 ATP molecules. Thus, aerobic respiration releases much more energy than anaerobic respiration. The amount of energy produced by aerobic respiration may explain why aerobic organisms came to dominate life on Earth.
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