Carbon Compounds in Cells

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Carbon Compounds in Cells

• Starr/Taggarts
• Biology
• The Unity and Diversity of Life, 9e
• Chapter 3

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Biomolecule Key Concepts

• There are four life molecules
• Carbohydrates
• Lipids
• Nucleic acids
• Proteins
• The biomolecules have specific structures and
  functions.
• They are built on a monomer/polymer concept and
  contain C, H, O, and N.

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Carbon

• Carbons versatile bonding C can form covalent
  bonds with up to four other atoms

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Monomer/Polymer

• Monomer molecular building block when linked
  together they form polymers
• Polymer chain or large structure resulting from
  linking monomers

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Condensation and Hydrolysis

• Dehydration Synthesis
• Two molecules
• combine
• Hydrolysis Reaction
• A molecule
• splits into two
• smaller ones

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Carbohydrates

• Also called saccharides with 121 ratio of CHO
• Function cells immediate energy source
• Monomer monosaccharide (ex. glucose)
• Polymer polysaccharide (ex. starch)
• Main types
• Monosaccharides
• Oligosaccharides
• Polysaccharides

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Carbohydrates
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Carbohydrates

• Monosaccharides
• 6 Carbon sugars
• Glucose
• Fructose
• Galactose
• 5 Carbon sugars
• Deoxyribose
• Ribose

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Carbohydrates

• Oligosaccharides
• Oligo- a few
• Disaccharides
• Sucrose
• Lactose
• Maltose
• Formed by condensation
  reactions

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Carbohydrates

• Complex
• Polysaccharides
• Starch
• Cellulose
• Glycogen
• Chitin

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Lipids

• Function energy storage and cell membrane
  structure (among others)
• Monomer glycerol and fatty acids (typical fat)
• Polymer the lipid itself
• Lipids with fatty acids
• Glycerides
• Phospholipids
• Waxes
• Lipids with no fatty acids
• Sterols

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Lipids
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Fatty Acids

• Carbon backbone
• Carboxyl group (- COOH)
• Unsaturated
• One or more double bonds in backbone
  
• Saturated
• All single bonds in backbone

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Triglycerides

• Neutral fats
• Three fatty acids
  and a glycerol
• Condensation
  reaction
• Bodys most abundant
  lipid
• Functions
• Energy reservoir
• Insulation

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Phospholipids

• Glycerol backbone
• Two fatty acid tails (hydrophobic)
• Phosphate-containing head (hydrophilic)
• Main materials of cell membranes

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Sterols

• Sterols
• No fatty acid tails
• Four carbon rings
• Promote fluidity in eukaryotic cell membranes
• Example cholesterol

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Waxes

• Long-chained fatty acids linked to alcohols or
  carbon rings
• Cover plant parts
• Help conserve water
• Fend off parasites
• Animals
• Protect
• Lubricate
• Impart pliability to skin and hair
• Repel water

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Nucleic Acids

• Function to transfer and act on genetic
  information
• Monomer nucleotide
• Polymer the nucleic acid
• Several types
• DNA
• RNA
• ATP

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Nucleic Acids - DNA

• Building blocks of DNA
• Four kinds of
  nucleotides
• Differ only in component bases

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Nucleotides and The Nucleic Acids

• Nucleotides
• Sugar
• Ribose or Deoxyribose
• Phosphate group
• Bases
• Single or double carbon rings with nitrogen

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DNA

• Double stranded
• Hydrogen bonds between strands
• Twisted helically
• Four kinds of nucleotide monomers (A, T, C, G)
• Encodes protein-building instructions

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DNA
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RNAs

• Single stranded
• Four kinds of nucleotide monomers (A, U, C, G)
• Key players in the protein-building processes
• mRNA, tRNA, rRNA

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Proteins

• Function build and repair cells
• Monomer amino acids
• Polymer protein

http//www.biochem.mpg.de/xray/homepages/blaesse/m
onomer.gif
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Structure of Amino Acids

• Central carbon atom
• An amino group
• A carboxyl group
• A hydrogen atom
• One or more atoms
  R Group

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Structural Formulas for Some Amino Acids
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Structural Formulas for Some Amino Acids
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Peptide Bond Formation

• A type of condensation reaction

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Four Levels of Protein Structure

• Primary
• Secondary
• Tertiary
• Quaternary

http//www.mcb.ucdavis.edu/faculty-labs/segel/mono
mer.jpg
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Protein Primary Structure

• Sequence of amino acids

disulfide bridges
Fig. 3.16, p. 43
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Second Level of Protein Structure

• Hydrogen bonds create this level
• Helical coiling called
  alpha helices
• Sheet-like pattern
  called Beta-pleated
  sheet

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Third Level of Protein Structure

• Additional folding of secondary structure
• R Group interactions
• Hydrogen bonds
• Disulfide bridges

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Fourth Level of Protein Structure

• Two or more polypeptide chains (subunits) joined
  by
• Weak bonds (Hydrogen bonds)
• Covalent bonds between sulfur atoms and R groups
• Collagen
• Keratin
• Hemoglobin

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Review

• Explain the 4 levels of protein structure.

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Ground Rules of Metabolism

• Starr/Taggarts
• Biology
• The Unity and Diversity of Life, 9e
• Chapter 6

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Structure of ATP

• ATP
• Our bodys main energy currency molecule

High E bonds!
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ATP Breakdown
High E bonds!
adenine
ribose
AMP
ADP
ATP
Fig. 6.8c, p. 100
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ATP is gained and used

• ATP is used in anabolic (building up) reactions
  that are endergonic (energy requiring).

Uses ATP!
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ATP is gained and used

• ATP is produced in catabolic (breaking down)
  reactions that are exergonic (energy producing).

Produces ATP!
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Free Energy

• Free energy is the energy available to perform
  work.
• Activation energy is a type of free energy
  required to get the chemical reaction started.

Free E vs. Time
Free
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Catabolic/Exergonic Reactions
Free E vs. Time

• Require ATP to provide activation energy
• Reactions also release energy!

Free
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Anabolic/Endergonic Reactions

• Require ATP to build the molecule(s) energy
• Reactions also store energy!

http//www.biology.arizona.edu/biochemistry/proble
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What do enzymes do?

• Enzymes are proteins that
• Speed up chemical reactions
• Are re-useable
• Lower the activation energy required!
• Act like a lock and key (specificity!)

R
P
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An example from your book
Fig. 6.16a, p. 105
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Enzyme Analogy
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Lock and Key Model
E-S Complex
Active site
Day 2
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How do enzymes speed up reactions?

• Help substrates find one another
• Help substrates orient toward one another
• Promote acid-base reactions that weaken covalent
  bonds in the substrate
• Shut out water and reduce the activation energy

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How Cells Use Organic Compounds

• Enzymes
• Mediate reactions
• Speed up the rate
• Classes of Reactions
• Functional-group transfer
• Electron transfer
• Rearrangement
• Condensation
• Cleavage