Biochemistry B-3.4 Summarize how the structure of organic molecules (including proteins, carbohydrates, and fats) are related to their caloric values B-3.5 Summarize the functions of proteins, carbohydrates, and fats in the human body

Key Concepts Organic molecules (as listed in the indicator) Caloric Value Protein: amino acid Carbohydrates: monosachharides Fats (lipids): glycerol, fatty acids

Objectives Distinguish between organic compounds and inorganic compounds. Summarize how the structures of organic molecules are related to their relative caloric values. Describe the bonding properties of carbon atoms. Compare the functions of proteins, carbohydrates, fats, and nucleic acids.

Vocabulary Words 1. Monomer 2. Polymer 3. Carbohydrate 4. Protein 5. Lipid 6. Nucleic acid 7. Fatty acid 8. Amino acid 9. Atom

All living things are based on atoms and their interactions.

Think About This… Why would a plant, like the Venus flytrap, need to consume animals if it already makes its own energy through photosynthesis?

The Answer Not all the materials a plant needs to maintain homeostasis is received through photosynthesis. Many plants absorb additional nutrients like phosphorus and nitrogen from the soil. The Venus flytrap grows in swampy areas where the soil is nutrient-poor. In order to get the additional nutrients it needs, it consumes animals by trapping them in their leaves. Once an animal touches the leaves, special cells allow the plant to snap shut (within 0.5 seconds) and trap the animal. Digestive chemicals allow the plant to consume the animal.

Important to Note In order to fully understand how living things work as a whole, it is important to understand its parts. Much of what happens in biology, at a basic level, relates to chemistry.

Living things consist of atoms of different elements. An atom is the smallest basic unit of matter. An element is one type of atom. H O Hydrogen atom (H) Oxygen atom (O)

Atoms Atom Composed of protons, neutron, & electrons Protons are positively charged (+) Neutrons are neutral (no charge) Electrons are negatively charged (-)

The nucleus has protons and neutrons. An atom has a nucleus and electrons. The nucleus has protons and neutrons. Electrons are in energy levels outside nucleus. Oxygen atom (O) Nucleus: 8 protons (+) 8 neutrons outermost energy level: 6 electrons (-) inner energy level: 2 electrons (-)

Atoms Protons and neutrons are held together by strong forces in the nucleus and the electrons are around the nucleus in the electron cloud. Electrons are in constant motion around the nucleus and are attracted to the protons in it. The # of protons (+) equals the # of electrons (-), so therefore atoms are neutral in overall charge.

Elements Element One particular type of atom There are over 100 known elements and about 24 are found in living organisms. Elements are either 1 or 2 letter symbols. Periodic Table of Elements Examples: Calcium (Ca), Hydrogen (H) They are arranged by atomic number on the Periodic Table of Elements.

Elements Atomic # refers to the # of protons in the atom. Mass # refers to the sum of protons and neutrons in the atom.

Chemical Compounds In nature, most elements are found combined with other elements in compounds. A chemical formula is how this relationship is shown Examples: H2O (2 Hydrogen atoms & 1 Oxygen atom) NaCl (1 Sodium atom & 1 Chlorine atom) CO2 (1 Carbon atom & 2 Oxygen atoms)

O A compound is made of atoms of different elements bonded together. water (H2O) O H _ +

A compound is made of atoms of different elements bonded together. carbon dioxide (CO2)

Chemical Compounds The chemical and physical properties of a chemical compound can be very different Example: H2O Water is a liquid Hydrogen alone is a gas Oxygen alone is a gas O H _ +

Chemical Bonds Chemical bond 2 Main Types: This bond formation involves the electrons (valence electrons). 2 Main Types: Ionic bond Covalent bond

Chemical Bonds Ionic Bonds (transferring electrons) Remember that atoms are neutrally charged because #protons = #electrons. An atom that loses an electron is positive. An atom that gains an electron is negative. Now the atom is an ion if it has lost/gained electron. Example: NaCl (sodium chloride)

Ions form when atoms gain or lose electrons. An ion is an atom that has gained or lost one or more electrons. positive ions negative ions Ionic bonds form between oppositely charged ions. Sodium atom (Na) Chlorine atom (CI) Sodium ion (Na+) Chloride ion (CI-) Na loses an electron to CI ionic bond gained electron

Atoms share pairs of electrons in covalent bonds. A covalent bond forms when atoms share a pair of electrons. multiple covalent bonds diatomic molecules covalent bonds Oxygen atom (O) Carbon atom (C) Carbon dioxide (CO2 )

Chemical Bonds Covalent Bonds (sharing of electrons) Form a molecule Share 2 electrons: single bond Share 4 electrons: double bond Share 6 electrons: triple bond Example: H2O (water)

Carbon-Based Molecules All organisms are composed of organic compounds, which contain carbon atoms.

Think…. Think about how a car is made. What features do all cars have? What makes one car different from another car? How does this compare to organisms?

Carbon: The Molecule of Life Carbon is the building block of life. The “molecule of life” Carbon is the basis of most molecules in living things.

What is an Organic Compound? Organic compounds have a carbon backbone. Example: C6H12O6 Inorganic compounds may contain carbon put don’t have a carbon backbone. Example: CO2

Carbon is a Versatile Atom It has four electrons in an outer shell that holds eight Carbon can share its electrons with other atoms to form up to four covalent bonds

Fundamental Structures Carbon has three fundamental structures (figure 2.10): Straight Chains Branched Chains Rings

Carbon can use its bonds to: Attach to other carbons Form an endless diversity of carbon skeletons

Shape of Organic Molecules Each type of organic molecule has a unique three-dimensional shape The shape determines its function in an organism

Giant Molecules - Polymers Large molecules are called polymers Polymers are built from smaller molecules called monomers Biologists call them macromolecules

Macromolecules in Organisms There are four categories of large molecules in cells: Carbohydrates Lipids Proteins Nucleic Acids

Examples of Polymers Proteins Lipids Carbohydrates Nucleic Acids

Carbohydrates Carbon Hydrogen Oxygen

Carbohydrates Carbohydrates include: Small sugar molecules in soft drinks Long starch molecules in pasta and potatoes

Types of Carbohydrates Monosaccharides Disaccharides Polysaccharides

Monosaccharides: Called simple sugars Include glucose, fructose, & galactose Have the same chemical, but different structural formulas C6H12O6

Monosaccharides Glucose is found in sports drinks Fructose is found in fruits Honey contains both glucose & fructose Galactose is called “milk sugar”

Monosaccharides Monosaccharides are the main fuel that cells use for cellular work ATP

Disaccharides A disaccharide is a double sugar They’re made by joining two monosaccharides Involves removing a water molecule (dehydration)

Disaccharides Sucrose (table sugar) Lactose (milk Sugar) Common disaccharides include: Sucrose (table sugar) Lactose (milk Sugar) Maltose (grain sugar)

Polysaccharides Starch is an example of a polysaccharide in plants Plant cells store starch for energy Potatoes and grains are major sources of starch in the human diet

Polysaccharides Glycogen is an example of a polysaccharide in animals Animals store excess sugar in the form of glycogen Glycogen is similar in structure to starch

Let’s Summarize CARBOHYDRATES Contains: Carbon, Hydrogen, Oxygen Sugars and Starches Monosaccharides (glucose, fructose, galactose) Disaccharides (sucrose, lactose, maltose) Polysaccharides (cellulose, glycogen) Main source of energy for cell. Synthesized through photosynthesis and broken down through digestion & respiration

Lipids Carbon Hydrogen Oxygen

Lipids Lipids are hydrophobic –”water fearing” Do NOT mix with water Includes fats, waxes, steroids, & oils FAT MOLECULE

Triglyceride Monomer of lipids Composed of Glycerol & 3 fatty acid chains Glycerol forms the “backbone” of the fat Organic Alcohol

Function of Lipids Fats store energy, help to insulate the body, and cushion and protect organs

Types of Fatty Acids Unsaturated fatty acids double bond between carbons Saturated fatty acids single bonds between carbons

Fats in Organisms Most animal fats have a high proportion of saturated fatty acids & exist as solids at room temperature (butter, margarine, shortening)

Fats in Organisms Most plant oils tend to be low in saturated fatty acids & exist as liquids at room temperature (oils)

Let’s Summarize LIPIDS Contains: Carbon, Hydrogen, Oxygen Made of glycerols and fatty acids Fats and Oils Saturated (waxes, butter) Unsaturated (olive oil) Polyunsaturated (peanut oil, sesame oil, corn oil) Cushion, insulation, organ protection, membrane structure, and energy

Proteins Carbon Hydrogen Oxygen Nitrogen

Proteins Proteins are polymers made of monomers called amino acids All proteins are made of 20 different amino acids linked in different orders Proteins are used to build cells, act as hormones & enzymes, and do much of the work in a cell

Four Types of Proteins Storage Structural Contractile Transport

Proteins as Enzymes Many proteins act as biological catalysts or enzymes Thousands of different enzymes exist in the body Enzymes control the rate of chemical reactions by weakening bonds, thus lowering the amount of activation energy needed for the reaction

Let’s Summarize PROTEINS Contains: Carbon, Hydrogen, Oxygen, Nitrogen Made of amino acids (monomer) Structural, Contractile, Transport, Storage Enzymes are an example

Nucleic Acids Carbon Hydrogen Oxygen Nitrogen Phosphorous

Nucleic Acids Store hereditary information Contain information for making all the body’s proteins Two types exist: DNA & RNA

DNA Two strands of DNA join together to form a double helix Base pair

Let’s Summarize NUCLEIC ACIDS Contains Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorous Nucleotides are the monomers Stores and transmits genetic information DNA and RNA