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Chapter 2 The Chemistry of Life. Life depends on chemistry. Millions of chemical reactions occur in living organisms every day. Organisms rely on chemical reactions in order to function. Food must be broken down, gases must be exchanged, molecules must be built. Levels of Organization. - PowerPoint PPT Presentation
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Chapter 2The Chemistry of Life
Life depends on chemistry.
Millions of chemical reactions occur in living organisms every day. Organisms rely on chemical reactions in order to function. Food must be broken down, gases must be exchanged, molecules
must be built.
Levels of Organization
Levels of Organization
http://micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10/
Section 2-1The Nature of Matter
Atoms Atom - Basic unit of matter.
All matter - including living things - is made up of groups of atoms “stuck” (bonded) together.
Elements Element – a kind or “species” of atom. There are
>100 elements or kinds of atoms. Living things are mostly made of six elements:
C, H, O, N, P, S (in order of most to least common)
1. Carbon2. Hydrogen3. Oxygen4. Nitrogen5. Phosphorus6. Sulfur
Elements
What element is…N?C?S?P?H?O?
Chemical Compounds Compound – a substance formed by the
chemical bonding of two or more elements Written as chemical formulas. Letter = element,
small number = how many atoms of the element Example: Water or H2O = 2 hydrogen atoms and 1
oxygen atom Example: Glucose or C6H12O6 = 6 carbon atoms, 12
hydrogen atoms, and 6 oxygen atoms
Chemical Compounds How many atoms of each element are in
these compounds?
(Nitric acid) HNO3
(Salt or Sodium Chloride) NaCl (Potassium Phosphate) KPO4
(Carbon dioxide) CO2
(Sulfur dioxide) SO2
(Glycerol) C3H8O3
CHECKPOINT A living thing is made up of cells, which are
made up of ___________, which are made up of ___________, which are different kinds of ___________.
Chemical Reactions Chemical reaction – atoms break and/or make bonds to
form different compoundsReactants – elements or compounds that enter into a
reactionProducts – elements or compounds that are
produced by the reaction
Example: 2H2O2 2H2O + O2 (reactant) (products)
Example: 2K + Cl2 2KCl (reactants) (product)
Chemical Reactions
Identify the products and reactants in each of these reactions.
8 Fe + S8 -> 8 FeS 2 H2O -> 2H2 + O2
Zn + 2 HCl -> ZnCl2 + H2
NaCl + AgNO3 -> NaNO3 + AgCl C10H8 + 12O2 -> 10CO2 + 4H2O
Section 2-3 Organic Molecules -Carbon Compounds
The Chemistry of Carbon Organic molecules - carbon based molecules that make up
living organisms Carbon forms the backbone or basic structure of all large
organic molecules, because it is abundant and flexible. Can bond with up to 4 other atoms at once. Can form single, double or triple bonds. Bonds easily with other carbon atoms to form the backbone of
large organic molecules. Can bond with many different elements
such as H, O, P, S, N.
Four Groups of Organic Molecules Most molecules in cells are so large they
are called macromolecules or “giant molecules.” Most macromolecules = polymers, which are
chains of repeating smaller molecules called monomers.
Polymerization – Joining monomers together to make a polymer
Organic molecules are classified into 4 groups:
1. Carbohydrates 2. Lipids 3. Nucleic acids 4. Proteins
Carbohydrates Elements: C, H, O Examples: Sugars and starches Functions:
Main source of energy for living things Used for structure in plants and some animals
Monomer – monosaccharide (simple sugar, like glucose), Polymer – polysaccharide (complex carbohydrate, like starch)
Nucleic Acids Composition: C, H, O, N, P Examples: DNA and RNA Function: Store and transmit genetic information Monomer – nucleotide / Polymer – nucleic acid
Proteins Composition: C, H, N, O Examples: enzymes, cell membrane
proteins, muscle proteins Functions:
Control rate of chemical reactions Regulate cell processes Structure Transport other substances
Monomer – amino acid / Polymer – polypeptide or protein
Structure or shape of a protein is extremely important to its function.
Lipids Composition: mostly C and H and some O Examples: Fats, oils, waxes Functions:
Energy storage Compose parts of biological membranes and waterproof
coverings Generally not
soluble in water No monomers or
polymers.
Section 2-4:Chemical Reactions and Enzymes
Energy in Reactions Chemical reactions don’t
happen automatically. (see graphs)
Activation energy – the energy needed to get a reaction started
Enzymes Some reactions are too
slow or require too much energy to happen in cells… unless they have help.
Enzymes = proteins that speed up chemical reactions that take place in cells
Enzymes work by lowering the activation energy of the reaction, making it easier which makes it faster.
Activation energy without enzyme
Activation energy with enzyme
Course of Reaction
Enzymes and Reactions
Think cars:Which car finishes the race first, the one that
took MORE gas before it would start, or the one that took LESS?
Enzyme Action Catalyst = A chemical that speeds up a
reaction without being used up or altered.
Enzymes are biological catalysts.
Each enzyme = unique shape = only binds to a specific reactant = only catalyzes one kind of reaction.
Active site
SubstratesProducts
Products are released. Enzyme is available again.
Chemical reaction occurs andsubstrates are changed to products.
Substrates bind to enzyme at active site.
Enzyme
Enzyme Action
Reactants bindto the enzyme atthe active site.
Chemical reaction changes reactants
to products.
Product is released. Enzyme is available again.
Enzyme Action
Enzyme Animations
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_enzymes_work.html
http://www.lpscience.fatcow.com/jwanamaker/animations/Enzyme%20activity.html
http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter25/animation__enzyme_action_and_the_hydrolysis_of_sucrose.html
http://www.kscience.co.uk/animations/model.swf
http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter2/animation__protein_denaturation.html
A change in the enzyme prevents reactants from
binding. Shapes don’t match.
Chemical reaction can’t occur. Reactants don’t get
changed to products.
Effects of Altered pH or Temperature on Enzyme Action
Summary: An enzyme outside of its OPTIMAL environment does not function as well, which means it will not make the reaction proceed as QUICKLY.
pH and Buffers pH scale – measurement system of
how acidic or basic something is / ranges from 0 –14
pH 7 = neutral (pure water) pH < 7 = acid (tomatoes, lemons) pH > 7 = base (soaps, cleaners)
pH in human cells must be kept between 6.5 and 7.5 or chemical reactions will be affected.
pH and temperature affect how well enzymes work because they change the shape of the protein.
Enzyme Thought Problems 1. Two plants live in a 35 degree environment. Which
one is more likely to survive and reproduce: the one whose enzymes work best at 30 degrees, or the one whose enzymes work best at 20 degrees? Why?
2. Your body temperature is 98.6 degrees, and your body’s pH is close to 7. At what temperature and pH do you think most human enzymes probably work?
3. Your cells can live at 90 degrees. The cells of bacteria from Antarctic ice, however, die at 70 degrees. Why?
4. Your body must maintain homeostasis: you must keep your body at a constant temperature and pH. Why is this essential to your survival?
Enzyme Thought Problems
5. At which pH do each of these enzymes perform optimally (best)? At which pH do these enzymes become denatured?
6. Which enzyme is probably found in a human stomach?