Carbon and Macromolecules

• Life on Earth is carbon-based
• After water, organisms primarily consist of carbon-based molecules
• Carbon atoms can form branching, long chains and rings

Carbon's Special Properties

• Carbon can form many shapes because it can form long chains, branching chains, and rings.
• Carbon chains and rings are skeletons for various chemical compounds
• Molecules with carbon bonded to other elements are organic compounds
• Carbon atoms can attach to functional groups which are set of atoms that influence chemical reactions

Organic Macromolecules

• Four classes of organic macromolecules are important to life.
  • Carbohydrates
  • Lipids
  • Proteins
  • Nucleic acids

Polymers

• Most biological macromolecules are polymers
• Most of the other parts of organisms besides water are macromolecules, which are large, structured molecules
• Macromolecules are polymers composed of monomers
• Digestion of polymers happens through hydrolysis
• Hydrolysis adds a water molecule, breaking bonds between monomers
• Polymers are built through dehydration synthesis
• Dehydration synthesis links monomers by removing water

Carbohydrates

• Carbohydrates are a source of dietary energy and animal building blocks
• Carbohydrates include both simple (monosaccharides) and large sugars (polysaccharides).
• Monosaccharides are basic sugars
• Disaccharides are double sugars formed when two monosaccharides join
• Many sugars have names ending in "-ose"
• Polysaccharides are made by joining many monosaccharides
  • Starch
  • Cellulose
• Animals produce glycogen and chitin from glucose

Lipids

• Lipids include fats, perform essential functions in the human body
• Energy storage
• Cushioning
• Insulation
• Membrane function
• Hormone regulation
• Lipids are a diverse group of organic, and hydrophobic compounds that do not mix with water
• Cell membranes are dependent on lipids
• Cells are surrounded by a membrane that regulates the passage of material in and out.
• Cell membranes comprised of a phospholipid bilayer
• Phospholipids have one hydrophilic phosphate head and two hydrophobic tails

Cholesterol

• Cholesterol is a lipid for membrane fluidity
• Cholesterol is used to make steroid hormones
• Cholesterol can be produced by the body or ingested
• High-density lipoprotein (HDL) reduces the risk of heart disease
• Low-density lipoprotein (LDL) increases risk of heart disease
• Cholesterol is found in animal-derived foods like eggs and red meat
• Dietary fat composed a triglyceride molecule
• Hydrocarbon chains in triglyceride fatty acid tails store energy (calories)
• A triglyceride is one glycerol molecule joined to three fatty acid molecules

Steroids

• Steroids are lipids with a skeleton of four fused rings with varied functions
• Steroids include cholesterol, estrogen & testosterone
• Anabolic steroids are synthetic variants of testosterone
• Anabolic steroids increase body mass but have dangerous side effects
• Diets contain saturated fats & unsaturated fats (including trans fats & omega-3 fats)

Fats - Saturated and Unsaturated

• Saturated fats are triglycerides with only single bonds in their hydrocarbon chains
  • Maximum number of hydrogens
  • Solid at room temperature
  • Abundant in animal products
  • Straight chains
  • Less healthy
• Unsaturated fats have double bonds in their hydrocarbon chains
  • Fewer hydrogens
  • Liquid at room temperature
  • Bent shape
  • More healthy
• Hydrogenation is a process that can produce trans fat
• Unsaturated fat containing an unusual bond, which are bad
• Some fats, omega-3 fatty acids, are essential to a healthy diet and reduce the risk of heart disease

Proteins

• Proteins are the most diverse molecules that play important roles in the body and their form fits their function
• Proteins perform a large variety of tasks:
  • Structure
  • Transport
  • Enzymatic
  • Defense
  • Movement
• Proteins are polymers of amino acid monomers
• Peptide bonds join amino acids together
• A polypeptide contains amino acids
• Twists and folds lead to a unique three-dimensional shape
• Chains may be joined together into a large complex
• Protein function is determined by a precise amino acid sequence & shape
• Altering the sequence can stop the protein from working , even a little

Protein Conformation and Denaturation

• Primary Sequence: amino acids
• Secondary: alpha helix or beta-pleated sheets
• Tertiary: Is a 3D Shape
• Quaternary: 2 tertiary structures
• Proteins can become denatured
• Denaturation: Chemical & physical properties of proteins are altered due to breakage of bonds by energy such as heat or light

Enzymes

• Enzymes are proteins that speed up reactions
• Metabolism is the sum of all chemical reactions in an organism
• An enzyme is a protein that speeds a chemical reaction without being changed itself
• Factors affecting enzyme performance:
  • Temperature
  • pH
  • Enzyme-substrate concentration
• Almost every metabolic reaction needs the help of an enzyme
• Enzymes speed chemical reactions by lowering activation energy
• Enzymes recognize one specific target molecule called its substrate
• Inhibitors are molecules that prevent enzymes from working

Enzyme Inhibition

• Competitive Inhibitors:
  • Bind to the active site
  • Directly blocks the active site
• Non-competitive Inhibitors:
  • Bind to a distant site
  • Changes the shape of the active site

Enzyme Function

• Like all proteins, enzyme function depends on shape
• Changes in shape can prevent function
• Lactase is an enzyme that breaks down lactose (milk sugar).
• Gene mutations can change the shape of lactase, making it ineffective

Nucleic Acids

• Nucleic acids store and transfer genetic information
  • DNA & RNA
  • Made of nucleotides which are monomers