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
– 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
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
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
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
DNA vs RNA
• DNA– 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
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