Term
What are the physical characteristics of water that make it useful to living things? |
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Definition
Water is unique in that it can exist in all three physical forms: gas, liquid, and solid. Water can store a lot of heat energy because it has a high specific heat index. This allows large bodies of water to help cool or heat the earth’s atmosphere, keeping our climate’s temperature more constant. Because water has mass or weight (8.33 pounds per gallon), when it is in motion it can move with great force that it shapes the land on the earth’s surface. |
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Term
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Definition
Carbohydrates are any of a large group of organic compounds occurring in foods and living tissues and including sugars, starch, and cellulose. They contain hydrogen and oxygen in the same ratio as water (2:1) and typically can be broken down to release energy in the animal body. |
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Term
What are the main types of monosaccharides and what roles do they have in living things? |
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Definition
Glucose, Fructose and Galactose are the main types of monosaccharides.
Monosaccharides are the major source of fuel for metabolism, being used both as an energy source (glucose being the most important in nature) and in biosynthesis. When monosaccharides are not immediately needed by many cells they are often converted to more space-efficient forms, often polysaccharides. |
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Term
How are disaccharides (sucrose, lactose, and maltose) formed from monosaccharides? |
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Definition
They are composed of two monosaccharide units bound together by a covalent bond known as a glycosidic linkage formed via a dehydration reaction, resulting in the loss of a hydrogen atom from one monosaccharide and a hydroxyl group from the other. The formula of unmodified disaccharides is C12H22O11. |
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Term
How is Benedict's test used to detect reducing and non-reducing sugars? |
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Definition
The Benedict's test identifies reducing sugars based on their ability to reduce the cupric ions to cuprous oxide at high pH values (basic solutions). Cuprous oxide is green to reddish orange. A green solution indicates a small amount of reducing sugars, while a reddish-orange solution indicates an abundance of reducing sugars. If the solution contains sucrose, a nonreducing sugar, there is no change in color in the solution, and it remains blue. |
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Term
What are the differences between the polysaccharides starch (amylose & amylopectin), glycogen and cellulose? |
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Definition
All are made from glucose and their function in living organisms is usually either structure- or storage-related. Starch and glycogen are made from alpha-glucose and used for storage. Cellulose and chitin are examples of structural polysaccharides and made from beta-glucose. |
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Term
Starch (Amylose & Amylopectin)
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Glycogen |
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Definition
-Starch (a polymer of glucose) is used as a storage polysaccharide in plants, being found in the form of both amylose and the branched amylopectin.
-In animals, the structurally similar glucose polymer is the more densely branched glycogen, sometimes called 'animal starch' which means it is also used for storage but in animals. Glycogen's properties allow it to be metabolized more quickly, which suits the active lives of moving animals.
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Term
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Definition
-Cellulose is used in the cell walls of plants and other organisms, and is claimed to be the most abundant organic molecule on earth. It has many uses such as a significant role in the paper and textile industries.
-Chitin has a similar structure, but has nitrogen-containing side branches, increasing its strength. It is found in arthropod exoskeletons and in the cell walls of some fungi. It also has multiple uses, including surgical threads. |
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Term
How is Iodine used to detect starch? |
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Definition
| Starch is a coiled polymer of glucose. Iodine reacts with the coiled molecules and turns bluish-black when added to a solution. A solution that remains a yellowish-brown color is a negative test for starch, whereas one that turns bluish-black is a positive test for starch. |
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Term
What are triglycerides, and what roles do they have in living things? |
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Definition
| Triglyceride is an ester composed of a glycerol bound to three fatty acids. It is the main constituent of vegetable oil and animal fats. Most of the fats digested by humans are triglycerides. They are formed from a single molecule of glycerol, combined with three molecules of fatty acid. The glycerol molecule has three hydroxyl (OH-) groups. Each fatty acid has a carboxyl group (COOH-). In triglycerides, the hydroxyl groups of the glycerol join the carboxyl groups of the fatty acid to form ester bonds. |
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Term
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Definition
| Saturated fat is when the carbon atoms have a single bond between them and as many hydrogen atoms as possible are bonded to the carbon atoms. In a healthy diet, people usually want to limit or avoid the saturated fat. Saturated fat is known to raise blood cholesterol levels. Saturated fat is solid at room temperature. |
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Term
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Definition
Unsaturated fats are when the carbon atom are double bonded and the molecule can absorb more hydrogen atoms. Unsaturated fats are liquid at room temperature and divided into two groups:
-Polyunsaturated fat: is found in fatty fish like salmon, tuna and sardines, and in oils like corn oil, safflower oil and soybean oil.
-Monounsaturated fat: is found in some nuts and canola oil, and olive oil.
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Term
What are phospholipids, and how are phospholipid molecules arranged in cell membranes? |
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Definition
They form the cell membrane and are like triglycerides but with one important difference. A phosphate functional group is substituted for one of the three fatty acids. The lipid bilayer, which creates the plasma membrane, consists of the lipid tails, which are hydrophobic, and the phospholipid heads, which are hydrophilic. Since the heads like water, they are on the outside and since the lipid tails are fearful of water they are within the two sides of the phospholipid heads. |
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Term
What makes up the primary, secondary, tertiary, and quaternary structure of a protein? |
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Definition
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