Chapter 3: Biochemistry Ms. Mezzetti Lynn English High School Science Department

Warm up: Define biochemistry What does “Chemistry of Life” mean?

Objectives: Students will be able to: Distinguish between organic and inorganic compounds. Explain the importance of carbon bonding in biological molecules. Summarize how large carbon molecules are synthesized and broken down. Describe how the breaking down of ATP supplies energy to drive chemical reactions.

Carbon Organic compounds contain carbon atoms and are found in living things. Therefore, all living organisms contain carbon Most inorganic compounds do not contain carbon atoms.

Carbon Bonding Carbon atoms can form: four covalent bonds single, double and triple bonds ring, branched or straight chains

Carbon Compounds Monomers: subunit of larger molecules Polymer: 3 or more monomers

Monomers/Polymers Monomer: Polymer: Monomer: Polymer:

Condensation Reactions/Hydrolysis Condensation Reactions remove water and combine monomers to make polymers Hydrolysis break down polymers into smaller macromolecules and monomer

Energy for life Adenosine triphosphate (ATP) stores and releases energy during cell processes, enabling organisms to function. ATP is the fuel/energy for life!

Organic Molecules Objectives: Students will be able to: Identify the 6 most abundant elements of life are C-H-N-O-P-S Distinguish 3 types of carbohydrates-monosaccharide's, disaccharides and polysaccharides. Explain how enzymes are a type of protein and catalyze chemical reactions. Identify the monomers and polymers of carbohydrates, proteins, lipids and nucleic acids. Compare the nucleic acids DNA and RNA.

6 Most abundant elements in nature Carbon Hydrogen Nitrogen Oxygen Phosphorus Sulfur

4 Classes of Organic Compounds We classify the major organic compounds into 4 groups: Carbohydrates Proteins Lipids Nucleic acids

Carbohydrates: Sugars and Starches composed of carbon, hydrogen, and oxygen in a 1:2:1 ratio- CH2O Used as short term energy End in ‘ose Animals store energy as glycogen Plants store energy as starch Plant cells made of cellulose Fungi cell walls contain chitin

Carbohydrates Monosaccharide's The monomers of carbohydrates are called monosaccharide's, simple sugars such as glucose, fructose and galactose Disaccharides Two monosaccharide's join to form a double sugar called a disaccharide such as sucrose (glucose + fructose) and lactose Polysaccharides Three or more monosaccharide's join to form large macromolecules such as starches, cellulose, chitin & glycogen. These are complex carbohydrates

Proteins Proteins are organic compounds composed mainly of carbon, hydrogen, oxygen, and nitrogen. C-H-O-N Proteins have many functions: --structural-such as muscle fiber collagen & keratin, defensive-antibodies, and catalytic roles-enzymes. Found in

Proteins Amino Acids: Proteins are made up of monomers called amino acids. There are 20 different types identified by their R group. Dipeptides: Two amino acids are joined by peptide bonds to form a dipeptide. Polypeptides: A long chain of amino acids is called a polypeptide. Usually 1000’s of amino acids joined together by peptide bonds.

Amino Acids There are 20 different amino acids. Each is different depending on it’s R group.

Structure of Proteins Primary-single chain of amino acids 4 Structures of proteins: Primary-single chain of amino acids Secondary- chains become folded or helical Tertiary-chains bend Quaternary-globular

Proteins Enzymes: are globular proteins that speed up chemical reactions and reduce the amount of activation energy needed for the reaction. There are 2200 different types of enzymes that catalyze 2200 specific types of reactions End in ‘ase: catalase, amylase, lipase are examples Enzymes are affected by pH, temperature and salinity

Enzyme Activity

Lipids Fatty Acids-building blocks of lipids (monomers) they have a hydrophilic (water loving) end and a hydrophobic (water fearing) end. Triglycerides Triglycerides consist of three fatty acids and one molecule of glycerol.

Lipids Lipids are: nonpolar molecules that store long term energy are an important part of cell membranes. Fats are a type of lipid: saturated (animal fat/solids/lard) unsaturated (fats from plants-oils/liquid) Carbons are full Single bonded Carbons not full Double bonded

Lipids Phospholipids: make up cell membranes; have a polar head and nonpolar tail Waxes: A wax is made of one long fatty acid chain joined to one long alcohol. Protect animal ears and plant leaves. Steroids: A steroid is a lipid composed of four fused carbon rings that help regulate body functions-testerone and estrogen Cholesterol is a steroid found in cell membranes that contributes to its permeability (letting things in and out)

Nucleic Acids Nucleotide A nucleic acid is a large and complex organic molecule that stores and transports information. The monomers , building blocks of nucleic acids are nucleotides. Nucleotides contain a 5-carbon sugar, nitrogenous base and a phosphate group

Nucleic Acids - DNA DNA- deoxyribonucleic acid (DNA) Stores genetic information for cell activities. Is double stranded (helix) Has nitrogenous bases adenine, thymine, guanine cytoseine

Nucleic Acids - RNA RNA- ribonucleic acid Important for protein synthesis. Is single stranded It’s nitrogenous bases adenine, uracil guanine cytoseine

Multiple Choice 1. Which of the following is not a function of polysaccharides? A. energy source B. energy storage C. structural support D. storage of genetic information

Multiple Choice, continued 2. Which of the following statements is false? F. A wax is a lipid. G. Starch is a lipid. H. Saturated fats are solid at room temperature. J. Unsaturated fats are liquid at room temperature.

Multiple Choice, continued 3. Which of the following molecules stores hereditary information? A. ATP B. DNA C. protein D. carbohydrates

Multiple Choice, continued 4. What is the name of the molecule in plants that stores sugars? A. starch B. protein C. cellulose D. glycogen

Multiple Choice, continued The figure below illustrates the basic structure of a cell membrane. Use the figure to answer the questions that follow. 5. Which of the following molecules make up the basic structure of a cell membrane? A. waxes B. steroids C. fatty acids D. phospholipids

Multiple Choice, continued The figure below illustrates the basic structure of a cell membrane. Use the figure to answer the questions that follow. 6. The “tails” of the molecules in the figure orient away from water. Which of the following describes the tail’s movement away from water? F. polar G. adhesive H. hydrophilic J. hydrophobic

Multiple Choice, continued 7. simple sugars : carbohydrates :: amino acids : A. lipids B. proteins C. nucleic acids D. amino acids

Short Response, continued Proteins are affected by environmental conditions such as heat and pH. Explain why the process of cooking an egg cannot be reversed. Answer: The heat that is added to the egg changes the bonds in the proteins and other molecules that make up the egg to such a large extent that the original protein shape can no longer be distinguished.

Open Response Enzymes are essential for the functioning of all cells. Part A Explain what enzymes do that is essential for cell function. Part B Explain the induced fit model of enzyme action. Answer: Part A Enzymes catalyze chemical reactions that are involved in important cell processes. Part B Bonding of the substrates to enzymes causes a slight change in the enzyme’s shape, thereby weakening some of the bonds and lowering activation energy.

Any Questions?