Download Organic Molecules Carbohydrates

Unit III: Lively Molecules
Organic Molecules & Enzymes
Chapter 2 – pp 50, 59 - 68
Review
1. What are the primary types of passive transport?
2. What are the two types of carrier-mediated transport?
3. Which of the following processes could occur only in the plasma
membrane of a living cell? a.) simple diffusion, b.) filtration,
c.) active transport, d.) osmosis
4. Osmosis is a special case of a.) pinocytosis, b.) carrier-mediated
transport, c.) active transport, d.) facilitated diffusion, e.) simple
diffusion
5. What were the three tonicities of osmosis?
Organic Molecules
The important organic molecules found in living things:
Carbohydrates
Sugar
Starch
Lipids
Proteins
Nucleic Acids
Fat
Enzymes
Deoxyribonucleic
Structural Proteins
Ribonucleic Acid
Cellulose
All contain Carbon, Hydrogen, and generally Oxygen.
Organic Molecules
Carbohydrates
• Hydrophilic organic molecule
• General formula
– (CH2O)n
– for glucose formula is C6H12O6
• Names of carbohydrates
– word root sacchar- or the suffix -ose often used
• monosaccharide or glucose
Carbohydrates
Monosaccharides
• Simple sugars
• General formula is C6H12O6
• Structural isomers
• Major monosaccharides
– glucose, galactose and fructose
• glucose is blood sugar
Carbohydrates
Disaccharides
• Composed of 2 monosaccharides
• Major disaccharides
– Sucrose = table sugar
• glucose + fructose
– Lactose = sugar in milk
• glucose + galactose
– Maltose = grain products
• glucose + glucose
Carbohydrates
Polysaccharides
• Long chains of glucose
• Cellulose:
• Starch:
• Glycogen:
Carbohydrates
Functions
• Converted to glucose and oxidized to make ATP
• Conjugated carbohydrate =
– glycolipids
– glycoproteins
– proteoglycans
• gels that hold cells and tissues together
Organic Molecules
Lipids
• Hydrophobic organic molecule
– composed of carbon, hydrogen and oxygen
• Less oxidized and thus has more calories/gram
• Five primary types in humans
Lipids
Fatty Acids
• Chain of 4 to 24 carbon atoms
– carboxyl (acid) group on one end
– methyl group on the other
• Classified
– saturated – unsaturated -
Lipids
Triglycerides (neutral fat)
• 3 fatty acids bonded to glycerol molecule
• dehydration synthesis
• At room temperature
– when liquid called oils
– when solid called fat
• Function -
Lipids
Phospholipids
• Triglyceride with a phosphate group
• Amphiphilic character
– fatty acid “tails” are hydrophobic
– phosphate “head” is hydrophilic
Glycocalyx
(extracellular
carbohydrates)
Integral protein
with channel
Glycolipid
CYTOPLASM
Integral
glycoproteins
Lipids
Eicosanoids
• Derived from a fatty acid
• Hormone-like chemical signals between cells
• Includes prostaglandins –
– role in inflammation, blood clotting, hormone action, labor
contractions, blood vessel diameter
Lipids
Steroids and Cholesterol
• Steroid =
• cortisol, progesterone, estrogens, testosterone and bile
acids
• Cholesterol
• naturally produced by our body
Organic Molecules
Proteins
Amino group
Central carbon
• Polymer of amino acids
Carboxylic acid group
R group (variable side chain
of one or more atoms)
• Amino acid =
– Amino (NH2), carboxyl (COOH) and radical group (R group)
• 20 unique amino acids
– -R groups differ
– properties determined by -R group
Proteins
Peptides
• Peptide =
• Named for the number of amino acids
– dipeptides
– tripeptides
– polypeptides
– proteins have more than 50
Proteins
Structure
• Primary structure
• Secondary structure
– hydrogen bonds between negative C=O and positive N-H groups
• Tertiary structure
• Quaternary structure
– associations of two or more separate polypeptide chains
Proteins
• Conformation –
• opening and closing of cell membrane pores
• Denaturation
– destroys function
• extreme heat or pH
Protein
Functions
•
•
•
•
•
Structure:
Communication:
Membrane Transport:
Recognition and protection:
Movement
– molecular motor =
• Cell adhesion:
• Catalysis: enzymes
Enzymes
• Proteins as biological catalysts
• Catalyst – a substance that can increase the rate at which a chemical
reaction takes place without actually entering into the reaction.
– promote rapid reaction rates
Enzymes
• Activation energy =
– Example: add heat energy or raise the temperature of the
reactants
• Enzymes (catalysts) speed up reactions by lowering the activation
energy
Activation
energy
Energy
Energy
Activation Energy
Activation
energy
Progress of reaction
Progress of reaction
Without a catalyst
With a catalyst
Steps of an Enzyme Reaction
1. The active site on an enzyme molecule fits the shape of the
substrate molecule
2. Substrate binds to active site forming enzyme-substrate complex
3. Enzyme breaks bonds in substrate
– Reaction products released
•
Enzyme repeats process over and over
Steps of an Enzyme Reaction
Cofactors and Coenzymes
• Cofactors
– nonprotein partners (iron, copper, zinc, magnesium or calcium
ions)
– bind to enzyme and change its shape
• Coenzymes
– organic cofactors derived from water-soluble vitamins (niacin,
riboflavin)
– transfer electrons between enzymes
Cofactors
• Example: amylase
– Catalyzes the conversion of starch to sugar
– Works best with NaCl
Enzymatic Action
• Astonishing speed
• Temperature and extremes in pH
– alter the structure or denature them
– enzymes vary in optimum pH
• Between a pH of 2 – 9.5
– temperature optimum = 37°C
Metabolic Pathways
• Chain of reactions
• Regulation of metabolic pathways
– activation or deactivation of the enzymes
– cells can turn on or off pathways