Inside Living Cells

These cards are revision guides for B2 gcse Science

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Aerobic Respiration

In aerobic respiration, oxygen is always required. During the process of aerobic respiration, the molecules of food are broken down to obtain energy. Oxygen is present at the end point of the electron acceptor. The molecules of fuel that are generally used by the cells of the body during the process of the respiration are composed of glucose, fatty acids and amino acids. In other words, when there is respiration through the aerobic process, Glucose together with Oxygen produces Energy, Carbon Dioxide and Water.

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Anaerobic Respiration

In plain language, anaerobic means where there is no air and thus anaerobic respiration is a term used for the respiration that occurs without the use of oxygen. In this process, the molecules carry oxidation, when oxygen is absent. This results in the production if energy or ATP. This type of respiration is also equivalent to fermentation when energy production path (Glycolytic pathway) is functioning in one cell. There are two processes of this respiration (i) alcoholic fermentation, where the Glucose gets broken down and produces Energy (ATP), Ethanol and Carbon Dioxide as well as (ii) Lactate fermentation where Glucose breaks itself into Energy and Lactic Acid.

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The respiratory system is the first link in the process of oxygen delivery to the body's tissues. The transport of oxygen in the air you breathe to the alveoli in your lungs allows for the diffusion of oxygen into the blood stream.

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Lactic Acid

Lactic acid has a dark side. When your body makes lactic acid, it splits into lactate ion (lactate) and hydrogen ion. Hydrogen ion is the acid in lactic acid. It interferes with electrical signals in your muscles and nerves, slows energy reactions, and impairs muscle contractions. The burn you feel in intense exercise is caused by hydrogen ion buildup. So, when you fatigue, don't blame it on lactic acid. Rather, place the blame where it belongs- on hydrogen ion.

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DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms. Nearly every cell in a person’s body has the same DNA. Most DNA is located in the cell nucleus (where it is called nuclear DNA), but a small amount of DNA can also be found in the mitochondria

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The information in DNA is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T). Human DNA consists of about 3 billion bases, and more than 99 percent of those bases are the same in all people. The order, or sequence, of these bases determines the information available for building and maintaining an organism, similar to the way in which letters of the alphabet appear in a certain order to form words and sentences.

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DNA Bases

DNA bases pair up with each other, A with T and C with G, to form units called base pairs. Each base is also attached to a sugar molecule and a phosphate molecule. Together, a base, sugar, and phosphate are called a nucleotide. Nucleotides are arranged in two long strands that form a spiral called a double helix. The structure of the double helix is somewhat like a ladder, with the base pairs forming the ladder’s rungs and the sugar and phosphate molecules forming the vertical sidepieces of the ladder.

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Genetic Engi

An important property of DNA is that it can replicate, or make copies of itself. Each strand of DNA in the double helix can serve as a pattern for duplicating the sequence of bases. This is critical when cells divide because each new cell needs to have an exact copy of the DNA present in the old cell.

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