Thursday, September 5. Why are carbohydrates important for us to consume?

Transcription

1 Bell Work: Thursday, September 5 Carbon Video Why are carbohydrates important for us to consume? 1

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3 CARBON What is it...and WY is it important? Carbon the building block of life, basis for most molecules that make up living things. atomic structure gives it unique bonding properties has 6 electrons (4 in outer energy level) can form up to four covalent bonds in order to be stable (single, double, and triple bonds are all possible) O C O O C C 3

4 Carbon chains can bond with carbon rings to form larger more complex molecules **All organisms are made of four types of carbon based molecules: Carbohydrates, Lipids, Proteins, and nucleic acids. All have different structures and functions but all form around carbon chains or rings. 4

5 Carbohydrates a biomolecule composed of carbon, oxygen, and hydrogen fruits and grains are high in carbohydrates 3 types: monosaccharides, disaccharides, and polysaccharides monosaccharides and disaccharide sugars require less effort in order to be used by the body WY are they important? used by our cells to provide energy to our bodies and structure to plant cells a) Monosaccharides simple sugar, composed of one ring Examples: fructose (found in fruits) & glucose (a sugar made by plant cells during photosynthesis b) Disaccharides two sugar carbohydrate (monosaccharide + monosaccharide= disaccharide) Examples: glucose and fructose combine to make sucrose (table sugar) 5

6 c) Polysaccharides polymers composed of many monosaccharide subunits polysaccharides are the hardest ones for our bodies to digest Examples: Starch, Glycogen, and Cellulose Starch made and stored by plants, used for energy by plant cells and as food reservoirs in seeds and bulbs. Glycogen made and stored in animals (example: mammals store energy in the liver this way) Cellulose forms all cell walls of plants/gives plants structural support and makes up the exoskeleton of insects. (It s the stringy fibers in celery) Foods loaded with Carbs include: pasta, white flour, white rice, bananas, potatoes, French fries, soft drinks, corn 6

7 Carbohydrate Loading: when runners or other athletes eat tons of carbs the day before the race or a game to store up extra energy to be burned later What happens when we eat them??? Once they are eaten and digested, or broken down, they can be taken up by the blood stream, becoming blood glucose. Insulin usually transports these simple sugars across the walls of body cells where it can then be used for energy. owever, diabetics insulin does not work properly and so the carbohydrates start to build up in the blood stream which causes sugar levels to rise. 7

8 Lipids -insoluble (cannot dissolve) in water because their molecules are non-polar and are not attracted to water molecules. -Examples: fats, oils, cholesterol -Made of chains of carbon, oxygen, and hydrogen WY ARE TEY IMPORTANT??? -Some lipids are broken down as a source of usable energy for cells, others are part of a cell's structure. 8

9 The fat/oils in plants and animals is very similar in structure -both have glycerol bonded to molecules called fatty acids Fatty acids- chains of carbon atoms bonded to hydrogen atoms -two types: saturated and unsaturated -saturated fatty acids: bad for you, contain only single bonds, they are solid at room temperature, examples: butter, lard -unsaturated fatty acids: better for you, contain double bonds, liquid at room temperature, examples: canola oil, olive oil 9

10 Lipids' Importance -very important for the proper functioning of organisms -cells use lipids for energy storage, insulation, and protective coverings -they are the major components of the membranes that surround all living cells 10

11 Trans fats -chemically altered vegetable oils -produced artificially in a process called hydrogenation (turns liquid oil into solid fat) -found in thousands of processed foods (sweets, to ready-made meals) -used because they are cheap, add bulk to products, have a neutral flavor and give the product a longer shelf life -no nutritional value -have been linked to high cholesterol 11

12 All cell membranes are made up of a lipid called a phospholipid. -made up of a glycerol, two fatty acids, and phosphate group. -they have a polar head and a nonpolar tail -this helps move things in and out of the cell Cholesterol -lipid with a ring structure -your body needs some cholesterol in order to function correctly -examples: it is part of the cell membrane, body uses it to make steroid hormones which are important to body's response to stress, sexual development, reproductive system, etc. BUT too much will accumulate in blood vessel walls and begin to narrow them -could lead to heart attacks and strokes. 12

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