Carbon Compounds in Cells

What is Organic Chemistry? Is the chemistry that deals with element carbon and one or more elements. All living organisms are made up of carbon-hints why we study it in biology. Examples of organic compounds are: Protein, Nucleic Acid, Carbohydrates, and Lipids Methane is the simplest organic compound

Carbon Bonding Carbon and the other elements are bonded covalently Oxygen, hydrogen, Nitrogen, Sulfur and carbon are most abundant elements in living matter Carbon can share pairs of electrons with as many as four other atoms to form organic molecules of several configuration Much of H and O is linked to form water

Functional Groups Are atoms or groups of atoms covalently bonded to a carbon backbone, they covey distinct properties, such as solubility and chemical reactivity, to the complete molecule. Know P. 38 You will have a quiz on this. Date: Friday, February 4, 2011

Four Families of Building Blocks Simple sugars, fatty acids, amino acids, and nucleotides Monomers can be joined to form larger polymers. Enzymes-is a class proteins that make metabolic reactions proceed faster

Ten Categories of Reactions 1- Functional Group transfer from one molecule to another 2- Electron transfer- stripped from one one molecule to another 3- Rearrangement of internal bond converts one type of organic molecule to another

Continue… 4- Condensation- two molecules to one 5- Cleavage- one molecule into two 6- Hydrolysis - break down compounds by adding water 7- Dehydration - two components brought together, produces H2O 8- Endergonic - requires the input of energy 9- Exergonic - releases energy 10- Redox - electron transfer reactions

Condensation Reaction One molecule is stripped of its H+, another is stripped of its OH-; then the two molecule fragments join to form a new compound and the H+ and OH- form water. Example: Starch formed by repeat condensation reaction

Hydrolysis Is the reserve: one molecule is split by the addition H+ and OH- (from water) to the components (condensation in reserve) Hydrolysis cleave polymer into smaller molecules when required for the building blocks for energy

Carbohydrates: Most Abundant element of life Made up of carbon, oxygen and hydrogen in a set proportion of 1:2:1 Monosaccharides (Simple Sugar) They are characteristics by solubility in water, sweet taste, and several –OH Examples: Glucose and Fructose: Used assembling larger carbohydrate Glucose

Carbohydrates: Continue Disaccharides: Consists of two monosaccharides joined together through the process of dehydration synthesis (which removes water in the process) Examples: Lactose (Glucose + Galactose) Present in Milk (dehydration synthesis) Sucrose (glucose + Fructose) is transported form of sugar used by plants and harvested by humans for use in food

Pentoses: 5 carbon sugar Continue Examples: Maltose (two glucose) is present in germinating seeds Pentoses: 5 carbon sugar Deoxyribose (sugar for DNA) Ribose (sugar for RNA)

Complex Carbohydrates Polysaccharides are macromolecules, polymers with few hundred to a few thousand monosaccharides joined together. Examples: Starch: Plant storage for energy; unbranched coil chain and easily hydrolyzed Cellulose: Found in plants for structure (insoluble) Glycogen: (animal cell storage) Chitin: polymer of glucose (arthropods exoskeleton)

Continue Examples Glycogen: High branched used by animals to store energy in muscles and liver. Is also converted to blood sugar when blood sugar drops Chitin: polysaccharide with nitrogen attached to glucose monomers which gives arthropods exoskeleton

Lipids A large biological molecules that does not consist of polymers. Lipids are greasy or oil compounds with little tendency to dissolve in water (hydrophobic) Can be broken down by hydrolysis reaction Function: energy storage, membrane structure and coatings

Continue: Lipids Fatty Acids Fatty Acid: is a long chain of mostly carbon and hydrogen atoms with a –COOH group at one end

Continue.. When they are part of complex lipids, the fatty acids resemble long flexible tails Unsaturated fats: fats are liquids (oils) at room temperature because one ore more double bonds between the carbons in the fatty acids permits “kinks” in the tails Example: Fish Oil Unsaturated Fats 

Saturated fats: (triglycerides) have a single C-C bonds in their fatty acid tails and are solids at room temperature They are tightly packed together Solid at room temperature Examples: Butter and Lard Diets rich in saturated fat leads to cardiovascular disease Triglycerides: “neutral” fats most abundant lipids and the richest source of energy

Fats Are constructed from two kinds of smaller molecules: Glycerol and fatty acids They are a rich source of energy, yielding more than twice the energy per weight basis as carbohydrates Provides an insulation blanket for animals to endure the harsh cold temperatures

Phospholipids Formed from 2 fatty acids + phosphate group attached to glycerol Provide structure support in membranes where they are arranged in bilayers

Steroids Have lipid characteristics by a carbon skeleton consisting of four fused rings Example: Cholesterol: common component of animal cell membranes and is also the precursor from which other steroids are synthesized (Example: vertebrate sex hormones)

Waxes They are formed by attachment of long chains of fatty acids to long chains alcohols or carbon rings Function: serve as coatings on plant parts and animals coverings

Amino Acids Are the building blocks of proteins Contain a amino group, carboxyl group and one of twenty varying R groups Covalently bonded to a central carbon atom

Protein Function as enzymes, in cell movements, as storage, and transport agents (hormones, antibodies, and structural material) Amino acids are the building blocks of proteins (peptide bonds) Amino acids coil into a 3D structure Heat can denatured proteins causing a change in shape and the ability to work properly Enzymes: special protein used to speed up a chemical reaction (biological catalyst)

Polypeptide Formation (2 to 3 amino acids) Primary Structure Primary structure is defined as ordered sequences of amino acids each linked together by peptide bonds to form polypeptide bonds The sequence of amino acids to determined by DNA and is unique for each kind of protein

Continue: Secondary structure Fibrous Proteins (beta pleated) : have polypeptide chains organized as strands or sheets Contribute to the shape, internal organization, and movement of cells. Globular Proteins (alpha helix): have chains folded into compact rounded shapes Example: Enzymes Keratin

Secondary Structure Helical coil shape (e.g. Hemoglobin) or sheetlike array (as in silk) that results from hydrogen bonding of side groups on the amino acids chains.

Tertiary Structure Is the result of folding due to interactions among R groups along polypeptide chain

Quaternary Structure Two or more polypeptide chains Hemoglobin- four interacting chains that form a globular protein Keratin and collagen– complex fibrous proteins

Glycoproteins Consist of olgosaccharides covalently bonded to proteins Abundantly found in exterior of animal cells and blood Lipoproteins: have both lipid and protein components Transport fats and cholesterol in the blood

Denaturation High Temperature or changes in pH can cause a loss of protein’s normal 3-D shape Pineapple Fresh vs Canned and Jello 31

Why is protein so important? Alternation of a cell’s DNA can result in the wrong amino acid insertion in a polypeptide chain Example: If valine is substituted for glutamate in hemoglobin, the result is HbS (Sickle Cell Anemia) Person who inherit two mutated genes for the beta chain of hemoglobin can make HbS Causes a person blood to be shaped like a sickle not a round disk 32

Nucleotides and Nucleic Acid Nucleotides consists of a: 5 carbon sugar (ribose or deoxyribose), a nitrogen base, and phosphate group Adenosine phosphate are chemical messenger (cAMP) or energy carriers (ATP) Nucleotide coenzyme transport hydrogen atoms and electrons (example NAD+ and FAD) Nucleotides serve as a building block for nucleic acid 33

Nucleic Acid Are polymers of nucleotides Four different kinds of nucleotides are strung together to form large single or double-stranded molecules Each strand’s backbone consists of joined sugars and phosphates with nitrogen bases projecting toward interior 34

DNA vs RNA DNA RNA 2 strand 5 carbon sugar: Deoxyribose Nitrogen bases: Adenine, Thymine, Cytosine, Guanine Inheritance RNA 1 strand 5 carbon sugar: Ribose Nitrogen Bases: adenine, uracil, cytosine, guanine Protein Synthesis 35