Unit 3:CELLS

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Unit 3CELLS

• Cellular Energy

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Carbon Compounds
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Objective

• What are the functions of each group of organic
  compounds?

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Lifes backbone
Interest Grabber
Section 2-3

• Most of the compounds that make up living things
  contain carbon. In fact, carbon makes up the
  basic structure, or backbone, of these
  compounds. Each atom of carbon has four electrons
  in its outer energy level, which makes it
  possible for each carbon atom to form four bonds
  with other atoms.
• As a result, carbon atoms can form long chains. A
  huge number of different carbon compounds exist.
  Each compound has a different structure. For
  example, carbon chains can be straight or
  branching. Also, other kinds of atoms can be
  attached to the carbon chain.

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Isooctane
Methane
Acetylene
Butadiene
Benzene
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Macromolecules giant molecules

• Formed by a process called polymerization

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Monomers

• Smaller units

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Polymers

• Linked up monomers

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Carbohydrates

• Compounds made up of carbon, hydrogen, and oxygen
  atoms usually in a ratio of 121
• Main source of energy
• The monomers of starch are sugars

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• Single sugar molecules are called monosaccharides
• The large macromolecules formed from
  monosaccharides are known as polysaccharides

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Lipids

• Made mostly from carbon and hydrogen atoms
• Used to store energy

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Lipid
Glycerol
Fatty Acids
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Proteins

• Macromolecules that contain nitrogen as well as
  carbon, hydrogen, and oxygen
• Proteins are polymers of molecules called amino
  acids

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Amino Acids
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• More than 20 different amino acids, can join to
  any other amino acid
• The instructions for arranging amino acids into
  many different proteins are stored in DNA
• Each protein has a specific role
• The shape of proteins can be very important

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Proteins
Amino Acids
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Nucleic Acids

• Macromolecules containing hydrogen, oxygen,
  nitrogen, carbon, and phosphorus

Double Helix
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Nucleotides

• Consists of 3 parts 5-carbon sugar, phosphate
  group and nitrogen base

Nitrogen Base
Phosphate group
5-Carbon Sugar
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2 kinds of nucleic acids

• RNA (ribonucleic acids) contains sugar ribose
• DNA (deoxyribonucleic acid) contains sugar
  deoxyribose

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Homework
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• Name four groups of organic compounds found in
  living things
• 2. Describe at least one function of each group
  of organic compounds

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• 3. Compare the structures and functions of lipids
  and starches

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Chemical Reactions and Enzymes
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Objectives

• What happens to chemical bonds during chemical
  reactions?
• How do energy changes affect whether a chemical
  reaction will occur?
• Why are enzymes important to living things?

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The Big Idea

• Living things are made up of chemical compounds
• Everything that happens to an organism is based
  on chemical reactions

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Chemical Reactions

• A process that changes or transforms one set of
  chemicals into another

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Reactants

• Elements or compounds that enter into a reaction

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Products

• Elements or compounds produced by a chemical
  reaction

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Example Reaction Getting rid of carbon dioxide

• In the blood
• In the lungs

CO2 H20 ? H2CO3 (carbonic acid)
H2CO3 ? CO2 H2O
Released as you breathe
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Energy in reactions
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Activation Energy

• The energy that is needed to get a reaction
  started

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Enzymes

• Some chemical reactions are too slow or have
  activation energies that are too high to make
  them practical for living tissue
• These chemical reactions are made possible by
  catalysts

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Catalyst

• Substance that speeds up the rate of chemical
  reactions
• Work by lowering a reactions activation energy

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Enzyme

• Biological catalysts
• Speed up reactions in cells
• Very specific
• Named for the reaction is catylzes
• Enzyme names always end in -ase

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Substrates

• The reactants of enzyme catalyzed reactions
• The active site of the enzyme and the substrate
  have complementary shapes
• Fit like a lock and key

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Enzyme Action
Enzyme substrate complex
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Enzyme (hexokinase)
Glucose
ADP
Substrates
Products
ATP
Glucose-6- phosphate
Active site
Products are released
Substrates bind to enzyme
Enzyme-substrate complex
Substrates are converted into products
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Regulation of Enzyme Activity

• Enzymes are affected by any variable that affects
  chemical reactions
• pH
• Temperature
• Concentration
• of enzyme

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Homework
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• What happens to chemical bonds during chemical
  reactions
• 2. Describe the role of energy in chemical
  reactions

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• 3. What are enzymes, and how are they important
  to living things?

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• 4. Describe how enzymes work, including the role
  of the enzyme substrate complex

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• 5. A change in pH can change the protein. How
  might a change in pH affect the function of an
  enzyme such as hexokinase (hint think about the
  analogy of the lock and key)