Molecules of Life

Organic Compounds: Molecules containing the element of carbon and at least one hydrogen atom. Chemistry of Carbon Atoms Carbon atoms form chains Carbon chains are backbone for molecules of life Functional Groups: particular atoms or clusters of atoms covalently bonded to carbon.

Functional Groups

Functional Groups cont.

Biologically Important Organic Molecules Hydrocarbons – C, H Carbohydrates – C, H, O Proteins – C, H, O, N, S Lipids – C, H, O Nucleic Acids – C, H, O, N, P

Hydrocarbons contain carbon (C) and hydrogen (H)

H C Hydrogen atom Carbon atom

H H H H C CH 4 Methane = simple hydrocarbon

Ethane Propane Examples of Hydrocarbons (carbon and hydrogen)

Gasoline Diesel – long chain hydroc-c-c-c-c-c-c-carbon

Monomers Dimers Polymers

What are monomers? Monomers = small molecules linked together to form chains. What are polymers? Polymers = monomers linked together in chains. Poly = many mer = parts or units Polymer = many parts linked together ?

Like a polymer Like monomers

OH HO O Dehydration (removal of water) synthesis (uniting) Monomer A HOH (Monomer A) (Monomer B) Dimer & Polymer formation (Monomer A) dimer = two monomers

Basic Review Questions Compare and contrast hydrolysis and dehydration synthesis. Define the terms monomer and polymer.

Carbohydrates Contain Carbon Hydrogen Oxygen Biologically important organic compounds Carbohydrates Proteins Lipids Nucleic Acids

Monosaccharides = sugar Ex. Glucose, Fructose, Galactose Dissaccharides Ex. Sucrose Polysaccharides Ex. Starch and Glycogen (long chains of glucose molecules) Carbohydrates

Energy for all functions, in all cells, in all living things In humans – growth, kidney function, nerve impulses, digestion, muscle action, heart beat, and more Glucose

OH HO O Dehydration (removal of water) synthesis (uniting) Monomer A Sucrose a Disaccharide (dimer = two monomers) HOH (Monomer A) (Monomer B) Monosaccharide (Monomer B) Disaccharide (dimer) formation Monosaccharide (Monomer A)

Biologist’s idea of Halloween fun Table Sugar Would carbohydrates be hydrophillic? Why or why not?

Examples of Polysaccharides: Potato Starch Cellulose leaves Glycogen (stored in liver and muscle cells) Broken down to use energy

Polysaccharide (polymer) is made of many monosaccharides (monomers) Monosaccharide Polysaccharide

Carb Review Questions Explain the role of carbohydrates for living things. If I gave you a list of chemical names, how would you be able to identify the carbohydrates?

Contain Carbon Hydrogen Oxygen Nitrogen (Sulfur) Biologically important organic compounds Carbohydrates Proteins Lipids Nucleic Acids

PROTEINS: Structure and Function of proteins controls structure and function of all life

Proteins are polymers made-up of monomers called amino acids. Protein = all blue circles linked together Amino acid = each individual blue circle

Amino Acids Dipeptide Polypeptide or Protein Proteins 36

These 20 different amino acids are analogous to an alphabet with 20 letters Each letter can be put together in any order, for any length to form an infinite number of proteins (words)

How do amino acids link to each other? Any car can be linked to any other car in any order for any length

Amino acids (like letters) Green part varies in each amino acid

Elephantx Letters spell word (protein) that means Elephant Changing “e” for “x” does not spell a word that means Elephant (or anything else)

Two amino acids are replaced; protein structure and function changes Normal structure = normal function Abnormal structure = abnormal function

Amino acid substitutions that have been found Amino acid substitutions that result in a disease Amino acid substitutions resulting sickle cell anemia Hemoglobin is polypeptide made of almost 400 amino acids. Normal RBC Sickle RBC Amino acid substitution (mutation) in hemoglobin results in sickle cell anemia

Proteins acting as ENZYMES

Enzymes speed up metabolic reactions by lowering energy barriers A catalyst is a chemical agent that speeds up a reaction without being consumed by the reaction An enzyme is a catalytic protein –Hydrolysis of sucrose by the enzyme sucrase is an example of an enzyme-catalyzed reaction © 2011 Pearson Education, Inc. Sucrase Sucrose (C 12 H 22 O 11 ) Fructose (C 6 H 12 O 6 ) Glucose (C 6 H 12 O 6 )

The Activation Energy Barrier Every chemical reaction between molecules involves bond breaking and bond forming The initial energy needed to start a chemical reaction is called the free energy of activation, or activation energy (E A ) © 2011 Pearson Education, Inc.

Figure 8.13 Course of reaction without enzyme E A without enzyme E A with enzyme is lower Course of reaction with enzyme Reactants Products  G is unaffected by enzyme Progress of the reaction Free energy

Substrate Specificity of Enzymes The reactant that an enzyme acts on is called the enzyme’s substrate The enzyme binds to its substrate, forming an enzyme-substrate complex The active site is the region on the enzyme where the substrate binds © 2011 Pearson Education, Inc.

Figure 8.14 Substrate Active site Enzyme Enzyme-substrate complex (a) (b)

Figure Substrates Substrates enter active site. Enzyme-substrate complex Substrates are held in active site by weak interactions. 1 2 Enzyme Active site

Figure Substrates Substrates enter active site. Enzyme-substrate complex Substrates are held in active site by weak interactions. Active site can lower E A and speed up a reaction Substrates are converted to products. 4 Enzyme Active site

Figure Substrates Substrates enter active site. Enzyme-substrate complex Enzyme Products Substrates are held in active site by weak interactions. Active site can lower E A and speed up a reaction. Active site is available for two new substrate molecules. Products are released. Substrates are converted to products

Effects of Local Conditions on Enzyme Activity The three-dimensional structure of enzymes are influenced by environmental conditions. An enzyme’s activity can be affected by –General environmental factors, such as temperature and pH –Chemicals that specifically influence the enzyme © 2011 Pearson Education, Inc.

Effects of Temperature and pH Each enzyme has an optimal temperature in which it can function –As temperature increases, collisions between substrates and active sites occur more frequently as molecules move faster. –TOO much of an increase in temperature will disrupt the weak bonds that stabilize the protein’s active conformation and the protein will denature. Each enzyme has an optimal pH in which it can function –Most enzymes have an optimal pH between 6-8. –Some digestive enzymes in the stomach work best at lower pH values (pH=2), while those in the intestine work best at a pH of 8. –The working environments influence the optimal pH of these enzymes. Optimal conditions favor the most active shape for the enzyme molecule © 2011 Pearson Education, Inc.

Figure 8.16 Optimal temperature for typical human enzyme (37°C) Optimal temperature for enzyme of thermophilic (heat-tolerant) bacteria (77°C) Temperature (°C) (a) Optimal temperature for two enzymes Rate of reaction pH (b) Optimal pH for two enzymes Optimal pH for pepsin (stomach enzyme) Optimal pH for trypsin (intestinal enzyme)

Figure 8.16a Optimal temperature for typical human enzyme (37°C) Optimal temperature for enzyme of thermophilic (heat-tolerant) bacteria (77°C) Temperature (°C) (a) Optimal temperature for two enzymes Rate of reaction

Figure 8.16b Rate of reaction pH (b) Optimal pH for two enzymes Optimal pH for pepsin (stomach enzyme) Optimal pH for trypsin (intestinal enzyme)

Protein Review Questions What are the monomers of a protein called? How many different monomers are there? What types of bonds hold the primary structure of a protein together? Please explain at least two roles of proteins in living things. How do pH and temperature affect the function of enzymes?

Contain Carbon Hydrogen Oxygen Biologically important organic compounds Carbohydrates Proteins Lipids

Lipids (fats) = polymers made of monomers called fatty acids and glycerol glycerol Fatty acid 58

A triglyceride 3 fatty acids 1 glycerol

Unsaturated carbon=carbon bond Saturated carbon-carbon bond 60

Be able to recognize saturated vs. unsaturated fatty acids saturated unsaturated

Steroids are also a type of lipid. They are always found in a fused, 4 ring formation.

Lipid Review Questions How would you recognize a triglyceride as opposed to a steroid? Differentiate between saturated and unsaturated fats. Be able to give an example of each. Compare and contrast the amount of energy stored in a lipid versus a carbohydrate. Explain why this might be the case.

NUCLEIC ACIDS Composed of NUCLEOTIDES Composed of NUCLEOTIDES Store & transmit heredity/genetic Store & transmit heredity/geneticinformation Nucleotides consist of 3 parts: Nucleotides consist of 3 parts: 1. 5-Carbon Sugar 2. Phosphate Group 3. Nitrogenous Base

DNA (deoxyribonucleic acid) Contains the genetic code of instructions that direct a cell's behavior through the synthesis of proteins.Contains the genetic code of instructions that direct a cell's behavior through the synthesis of proteins. Found in the nucleus.Found in the nucleus.

RNA (ribonucleic acid) directs cellular protein synthesisdirects cellular protein synthesis found in ribosomes & nucleolifound in ribosomes & nucleoli

RNA structure: DNA Structure: Single Strand Double Helix

Nucleic Acid Review Questions What are the monomers of nucleic acids called? What are the three things the monomers are composed of? Compare and contrast the structures of DNA and RNA.