week-05-CH-lipids-memb

week-05-CH-lipids-memb - BIOL 101 - Fall 2007- Week 5 - C-H...

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Week 5 - Page - 1- BIOL 101 - Fall 2007- Week 5 - C-H - Lipids - Membranes Please note - all lecture notes are© Timothy C. Hall, Biology Dept., Texas A&M University CARBOHYDRATES Metabolism Metabolism is the name given to the processes by which living cells make the materials needed to survive. Processes that build up molecules are examples of anabolic metabolism and those that break down molecules are catabolic . We will soon learn about photosynthesis, a major anabolic process in which sugars are made from 22 carbon dioxide (CO ) in the air and water (H O). However, there are many interacting metabolic pathways that cells (plant, animal, bacterial and fungal) use to synthesize (make) a myriad of different compounds. Major classes of compounds include carbohydrates, fats, proteins and nucleic acids, and there are many more metabolites . Anabolic processes generally require the input of energy while catabolic processes usually release energy. Useful websites include: http://www.genome.ad.jp/kegg/pathway/map/map01100.html http://home.planet.nl/~pvsanten/mmp/mmp.html Biomolecules Of the 92 naturally-occurring elements, about 16 are essential to most plants. Four elements make up >95% of the mass of most plants: C CARBON H HYDROGEN O OXYGEN N NITROGEN Most molecules containing C are organic compounds, but C compounds lacking H are classified as inorganic . Biochemicals are organic and inorganic compounds found in living organisms. Most of the mass of plants is made of four kinds of molecules: CARBOHYDRATES, LIPIDS, NUCLEIC ACIDS, PROTEINS Many molecules exist as single units called monomers . Monomers are often linked to give dimers , trimers or (as in most plant tissues) polymers . Polymers may be of identical or similar monomers. Initially, we will look at carbohydrates, compounds that are made up of carbon, hydrogen and oxygen 2 in the ratio CH O. Fats are also made up of these elements, but they are present in different ratios and have other differences.
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Week 5 - Page - 2- Glyceraldehyde, a triose Glycerol $ -ribose, a pentose " -glucose, a hexose $ -deoxyribose, a pentose Carbohydrates 2n These have the general formula (CH O) . When n =3, the resulting compound is a triose. When n =5, the resulting compound is a pentose. When n =6, the resulting compound is a hexose. 61 26 Glucose, a sweet powdery substance, has the general formula C H O . It is the starting point 22 (substrate) for respiration, an catabolic process which breaks glucose back down to CO and H O. When humans breathe, they are carrying out the process of respiration and are using stored energy in the form of carbohydrates to produce chemical energy that can be used in many ways, including 2 movement. We breathe in oxygen (O ) and breathe out CO and H O. As shown above, glucose can be represented as a straight chain structure or as a ring structure. The forms are interconvertible. There are many different ways in which C, H and O can be arranged to form a hexose. These different arrangements give very different properties to the resulting compounds. To help describe the structures, the C atoms are numbered from C1 to C6.
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This note was uploaded on 03/25/2008 for the course BIOL 101 taught by Professor Hall during the Fall '07 term at Texas A&M.

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week-05-CH-lipids-memb - BIOL 101 - Fall 2007- Week 5 - C-H...

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