Carbon Compounds Why is carbon the basis for life? It has 4 electrons in its outer (valence)...
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Transcript of Carbon Compounds Why is carbon the basis for life? It has 4 electrons in its outer (valence)...
BiochemistryThe chemical basis of life
Based on organic (carbon) chemistry
Carbon Compounds
Why is carbon the basis for life?
• It has 4 electrons in its outer (valence) electron shell.
• Octet rule: The most stable
elements have 8 electrons in its outer shell, with few exceptions.
• Carbon forms 4 covalent bonds to fulfill the octet rule.
• Therefore, Carbon is really good at forming rings and chains
Methane Acetylene Butadiene Benzene Isooctane
Section 2-3Some Carbon Compounds
Organic compounds• Always contain carbon (carbon can bond with
many other elements)• Small units called monomers join together to
form polymers
Making polymers
• Think of molecules as “mers”
• When 2 monomers join, they form dimers.
• Adding more monomers form polymers.
1 “mer” = monomer 2 “mers” (mer+mer) = dimer 3 or more “mers” (mer+mer+mer+mer) = polymer
4 Important carbon polymers & complex molecules
1. Carbohydrates 2. Proteins3. Lipids4. Nucleic acids
Dehydration synthesis - • Joining monomers into
polymers while taking away water molecules
• A-OH + B-HAB + H2O
• Dehydrate – to take away water
• Synthesis – to make
Carbohydrates – sugars, starch, cellulose, chitin• Function: quick energy
(4 calories per gram)
• Building blocks: Monosaccharides or simple sugars like glucose C6H12O6
• Carbohydrates provide cellular energy• Cell Membrane functions and support• Examples:
– Monosaccharides (glucose, fructose, etc)– Disaccharides (sucrose, lactose, etc)– Polysaccharides (starch, cellulose, glycogen, chitin)
Starch
Glucose
Section 2-3 Starch
Proteins – used for structure and function
• Purpose: can be used for energy (4 calories per gram) but mostly used for cell structure and function
• Building blocks: amino acids (20) held together by peptide bonds
• Sometimes very large, complex molecules
General structure Alanine Serine
Section 2-3
Amino group Carboxyl group
Amino Acids
Antibodies
Hormones
Hemoglobin
Enzymes
Muscle fibers
Enzymes -Functional proteins in your body
“Enzymes are proteins that act as catalysts and control chemical reactions”.
• Enzymes are usually named with –ase ending.• Ex: Peptidase in the stomach breaks down peptide
bonds (proteins) • Substrates are the molecules enzymes act upon (Ex:
proteins or disaccharides)• Enzymes are catalysts = speeds up reactions
“ose” for sugars “ase” for enzymes
• What would you call the enzyme that breaks down sucrose?
• What would you call the enzyme that breaks down lactose?
• What would you call the enzyme that breaks down maltose?
How enzymes work on reactants (substrates)
Label the diagram in your notes.
Two laws of thermodynamics
• 1st law of thermodynamics: conservation of energy. Energy is neither lost nor gained but just changes from one form to another.
• 2nd law of thermodynamics: entropy– Tendency to move from order to disorder.
Conservation of energy
• Energy can neither be created nor destroyed.
• Energy can only be changed from one form to another.
Entropy: disorder
• For living beings or just molecules to be organized, there must be a lot of energy.
• Very little energy is needed to create disorder.
A B + C
• Breaking down a reactant (A) into products (B and C)
• Requires little energy to start breaking down substances
• Exergonic reaction – releases energy
A + B C
• Making a product (C) from reactants (A and B)
• Requires much energy to start this reaction – Why?
• Endergonic reaction – absorbs energy
Energy graphs
Activation energy
• Activation energy: how much energy is required to start a reaction
• http://www.youtube.com/watch?v=-vgkvUxxZFg&feature=related
• http://www.britishpathe.com/record.php?id=50144
Activation energy on two types of reactions
Energy-Absorbing Reaction Energy-Releasing Reaction
Products
Products
Activation energy
Activation energy
Reactants
Reactants
Graph of Energy of a reaction
Which graph is Endergonic?
Which graph is Exergonic?
Enzyme action
• Enzymes: special proteins that help to reduce the activation energy (Ea)
• What will enzymes do to the speed (rate) of a reaction?
Effects of Enzymes
Reaction pathwaywithout enzyme Activation energy
without enzyme
Activationenergywith enzymeReaction pathway
with enzyme
Reactants
Products
• How do enzymes help with the activation energy required for metabolic processes?
Enzymes and Metabolism
• Enzymes facilitate the metabolic processes (chemical reactions) to sustain life.
• Enzymes help to maintain homeostasis.
• Enzymes help to build cells.
• Enzymes help in reproduction.
Glucose
Substrates
ATP
Substratesbind toenzyme
Substratesare convertedinto products
Enzyme-substratecomplex
Enzyme(hexokinase)
ADPProducts
Glucose-6-phosphate
Productsare released
Section 2-4
Figure 2-21 Enzyme Action
Active site
Enzyme activity (4)
Proteins can be Denatured
• Denature – “destroying the nature or the shape”– changes the Secondary,
Tertiary or Quaternary structure of a protein.
• Salts, Heat and pH changes affect proteins (polypeptides) and may denature them.
In living cells, biological pathways are NOT a one step process
• What would happen in this process if enzyme 2 was denatured?
A
B
C
D
E
Lipids – fats, oils, waxes, sterols• Function: long term stored energy • (9 calories per gram)
• Provides insulation & cushioning• Building blocks: 1 glycerol & 3 fatty acids• Examples:
– Saturated (animal fats)– Unsaturated (plant oils)– phospholipids are the basic structure of cell
membranes.– Steroids are signal chemicals to initiate a process
in the body
Examples of Sterols
• cholesterol • steroids• estrogen• testosterone
Click on the testosterone molecule
Lipid Structure
Some examples of lipids
Lipids are a vital component of cell membranes
Nucleic acids• Functions: store &
translate hereditary information.
• Building blocks: Monomers of nucleotides (sugar, phosphate, base)
• Examples:– DNA (stores code)– RNA (translates code to
protein)
Parts of a Nucelotide
• Phosphate• Sugar• Nitrogen containing Base
What does DNA do?
• DNA does NOT govern cell activity directly!!
• “DNA is the code for the making of proteins used for structure and function”.
The 4 Bases found in DNA
The 4 Bases found in DNA as Nucleotides
DNA Structure
Base Pairing in DNA
A ↔ TC ↔ G
How does the decoding work?• The ATC’s & G’s of the DNA are transcribed into an
RNA code then read in groups of 3 letters.• DNA: TAC,GCT,CCC,TCT,AAT,ATC,CTG
• RNA: AUG,CGA,GGG,AGA,UUA,UAG,GAC
• Ribosomes read AUG – CGA – GGG – AGA – UUA – UAG – GAC.
• Each 3 nucleotide “word” is called a codon.
Ribosomes use this decoding scheme to determine how to build the appropriate protein.
DNA
Polypeptide= protein
Amino acids
Organic MacroMolecule Foldable1. Name of macromolecule group
– Water, Vitamins & Minerals, Lipids, – Nucleic Acids, Proteins, Carbohydrates
2. Types of molecules in the group• (ex, sugars, starches, cellulose, chitin)
3. Monomer used as building blocks• (built from monosaccharides)
4. Examples of the polymers• Simple sugars, honey, pasta, potato, rice, grains)
5. Pictures/examples (3) of food sources that provide the building blocks to our bodies.
Organic macromolecule
Monomer(building block)
Polymer(Types)
Carbohydrates4 calories per gram
Monosaccharide (ex: Glucose)
Polysaccharides(ex: sugars, starch, cellulose, glycogen,
chitin, etc.)
Proteins4 calories per gram
Amino acids Structural proteins and enzymes
Lipids9 calories per gram
Glycerol and fatty acids
Fats, oils, waxes, sterols
Nucleic acidsHeredity information
Nucleotides DNA, RNA