the molecules of life chapter 5. 5.1- carbon is the main ingredient of organic molecules why are...
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5.1- Carbon is the main ingredient of organic molecules
Why are carbon atoms so common in living things? ◦4 electrons in its highest occupied level making
it very reactive. Organic molecules
Always contain carbonInorganic Molecules
Never contain carbon
Carbon Skeletons and Functional Groups Carbon Skeletons – “the backbones of organic
molecules.
Functional Groups – a group of atoms within a molecule that interacts in predictable ways with other molecules.
Monomers◦Smaller molecular
units, building blocks of polymers
Polymers◦Many monomers
linked together into long chains
Life’s Large (macromolecules)◦Carbohydrates◦Lipids◦Proteins◦Nucleic acids
Building and Breaking Polymers
◦Dehydration reaction Each time a monomer is
added to a chain, a water molecule is released
◦Hydrolysis reaction Cells break bonds between
monomers by adding water to them (the reverse of dehydration)
5.2 Carbohydrates provide fuel and building material◦Objectives
Describe the basic structure and function of sugars.
Name three polysaccharides and describe their functions
◦Key terms◦Carbohydrate◦Monosaccharide◦Disaccharide◦Polysaccharide◦Starch◦Glycogen◦Cellulose
What do athletes mean when they talk about “carbs”?
◦Carbs=Carbohydrates=sugar molecules Sports drinks- small molecules
Pasta- long molecules (Starch)
Sugars – The main fuel supply for cellular work. ◦Carbohydrate – An organic compound made up
of sugar molecules Carbon, Hydrogen, Oxygen Ratio – 1 C : 2 H : 1 O
◦Monosaccharide – Simple sugars containing just one sugar unit Examples – glucose, fructose and galactose.
Disaccharides – Using the dehydration reaction, cells construct a disaccharide (double sugar)◦Most common disaccharide-Sucrose
Glucose monomer and a fructose monomer
Polysaccharides – Long polymer made up of simple sugars monomers (Complex Carbohydrates)◦Common Polysaccharides-Starch, glycogen,
cellulose
5.3 – Lipids include fats and steroids
◦Objectives Identify a general characteristic of lipids Describe the structure and functions of fats Describe the structure and functions of steriods
◦Key terms Lipid Hydrophobic Saturated fat Unsaturated fat Steroid Cholesterol
“Do Now” – Salad Dressing containers usually have a label that says, “Shake well before using” Why?
The oil in most dressings doesn’t mix well with the vinegar (mostly water).
Characteristics of lipids◦Lipids are water-avoiding molecules
(Hydrophobic – water fearing)
Fats◦Consist of a three-carbon skeleton
(glycerol) attached to three fatty acids (long hydrocarbon chains).
Saturated fats◦Contains maximum number of
hydrogen atoms◦All single bonds
Unsaturated fats◦Contains less than the maximum
number of hydrogen atoms.◦One double bond
Steroids◦Lipid where the carbon skeleton
forms four fused “rings” Examples – Estrogen and
Testosterone Function – send chemical signals
throughout the body◦Cholesterol
A steroid that is found in the membrane surrounding your cells
High levels are linked with increase risk for cardiovascular disease (heart and blood vessel)
5.4 – Proteins perform most functions in cells.
Do now – Make a list of facts you already know about proteins.
Polymer Energy Builds muscles
Objectives ◦List functions of proteins◦Describe the structure of amino acids and
proteins◦Describe factors that influence protein shape
The Functions of Proteins◦A protein is a polymer made from only 20
monomers (amino acids)◦Responsible for day-to-day functions
Examples of typical protein functions◦Form hair and fur◦Make up muscles◦Defend the body from harmful microorganisms◦Send messages from one cell to another◦Control chemical reactions in cells
Amino Acids◦Monomer consists of a central carbon
atom bonded to 4 partners. Hydrogen group Carboxyl group Amino group Functional group (side group) or (R-
group)
Examples◦Leucine
◦Serine
Building a Protein◦Cells link monomers of proteins (amino acids)
together to create polypeptide Chains Building molecules needs a reaction. Which
reaction?◦Dehydration reaction
◦Alphabet = 26 letters◦Creates - ? Words◦Amino acids = 20 “letters”◦Creates - ? Polypeptide chains
Protein Shape◦Protein are not linear, but 3D
carefully twisted and folded into a particular shape.
◦Will not work properly unless it is in it’s unique shape.
◦Shape is influenced by its environment.
◦Changes in its environment can “unravel” the protein” (denaturation) Change in temperature pH
5.5 – Enzymes are proteins that speed up specific reactions in cells.
◦Objectives: Explain how enzymes affect activation energy. Describe how an enzyme’s shape is important to its function.
◦Key Terms Activation energy Catalyst Enzyme Substrate Active site
Enzymes and Activation NRG◦Where does the NRG from a lit
candle come from? From lighting a match. This is
start-up NRG or (activation energy)
Catalyst – compounds that speed up chemical reactions.◦By weakening bonds chemical
reactions occur faster and/or with less NRG
The main catalysts of chemical reactions in organisms are specialized proteins called enzymes.