Intermolecular Forces. Bonding Ionic Covalent Polar covalent.
Comparison of Ionic, Polar Covalent, and Nonpolar Covalent Bonds.
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Transcript of Comparison of Ionic, Polar Covalent, and Nonpolar Covalent Bonds.
Formation of an Ionic Bond
• A valance electron from Na is transferred to Cl• Cl now has 18e and 17p resulting in a – charge• Na has 10e and 11P resulting in a + charge.
Nonpolar and Polar Covalent Bonds
Non polar covalent Bonds equally share electrons
Polar covalent bonds share electrons unequally
Hydrogen Bonds• Too weak to bind atoms together
– (intra-molecular bonds= within molecule)
• Important as inter-molecular bonds– between to different molecules– Important for giving proteins (enzymes) and
DNA both shape and functionality.
• Hold water molecules together– Responsible for surface tension in water
Properties of Water• Water makes up to 50-80% of all living cells. • Water stabilizes internal temperature of the body
– Hydrogen bonds stabilize large shifts in temperature
• Evaporate cooling (sweating) is critical from maintaining 98.6 degrees temperature in hot environments or increased physical workloads.
• Water is necessary for all biochemical reactions that take place in the body.
Polarity of Water
• Oxygen has a greater electronegativity.
• Hydrogen’s one electron spend more time in Oxygen's outermost energy level.
• The result is more electrons around the oxygen making it more negative.
• Hydrogen losses its electron. Its proton is unopposed making it more positive.
Properties of Water
• Water makes up to 50-80% of all living cells. • Water stabilizes internal temperature of the body
– Hydrogen bonds stabilize large shifts in temperature
• Evaporate cooling (sweating) is critical for maintaining 98.6 degrees temperature in hot environments or increased physical workloads.
• Water is necessary for all biochemical reactions that take place in the body.
Properties of Water• Water is a powerful splitting agent. (Hydrolysis) means
water splitting. Occurs in breaking down reactions• Is known as the universal solvent. ( Polarity allows it to
dissolve stuff.) water molecules slit the ionic bonds in Na+Cl-
Polarity
• Polar molecules associate with water and will dissociate from lipids (fats) . – Polar = hydrophilic (philic = loving)– Lipophobic (lipid fearing)
• Non-polar molecules associate with lipids will not associate with water and are considered to be – Non-polar = hydrophobic (water fearing)– Lipophilic= Lipid loving
Organic Compounds• Organic compounds contain carbon as the backbone.
• It has the ability to create 4 covalent bonds which is important for making large complex structures.
• Organic compounds include :– Carbohydrates (sugars)– Lipids (fats and oils)– Proteins ( muscle, enzymes)– Nucleic acids (DNA and RNA)
• They may be built up or broken down depending on what the system requires.
• May have a variety of functional groups
Dehydration Synthesis
• Dehydrate( remove water)/ Synthesis( Build) • Monomers bond together to form a polymer with the
removal of a water molecule (dehydration)• Removal OH– of one and H+ of the other hydroxyl group
forms the water. – A covalent bond will result.
Hydrolysis
• Translates into Water/splitting• Addition of a water to a polymer causes (lysis) of the
covalent bond joining the 2 monomers.– Reestablishes the hydroxyl groups in both monomers
• All digestion reactions consists of hydrolysis reactions
Monomers/Polymers
Carbohydrates Monosaccharides Polysaccharides
Fats (lipids) Glycerol + 3 fatty Acids Triglycerides
Protein Amino acids Polypeptide
Nucleic Acidsnucleotides DNA, RNA
Dehydration Synthesis
Hydrolysis
CarbohydratesHydrophilic organic molecule that : contain carbon, hydrogen, and
oxygen 1:2:1 atomic ratio( carbo/carbon:hydrate/H2O)
– i.e. glucose = C6H12O6
• Names of carbohydrates– word root sacchar- or the suffix -ose often used
• Glucose is a monosaccharide which functions as a major fuel source for the cells.
Carbohydrates
• Dehydration synthesis reactions allow the cell store excess carbohydrates in the form of glycogen.
• Hydrolysis reactions allow the cell to break the bonds holding the polysaccharide together allowing it to release more simple sugars.
Disaccharides
• Major disaccharides– sucrose = table sugar
• glucose + fructose– Lactose = sugar in milk
• glucose + galactose– Maltose = grain products
• glucose + glucose
• All digested carbohydrates converted to glucose broken down in ATP (Cellular fuel).
Glycogen• Glycogen is an energy storage polysaccharide produced
by animals. 2 storage sites:– Liver cell: synthesize glycogen after a meal which can be broken
down later to maintains blood glucose levels.– Muscle cells: Store glycogen within the muscle at is only used by
the muscle cell.
Starch and Cellulose• Starch: is the storage form of sugar produced by plants. We
produce an enzyme that breaks the bonds between the sugars allowing digestion to occur. i.e. potatoes and grains
• Cellulose: provides structure to plants but contains a different type of bond. The β form is insoluble because we don’t produce the enzyme .i.e. dietary fiber
Lipids• Hydrophobic organic molecule
– Composed of carbon, hydrogen and oxygen– Better fuel source since it contains many more carbon and
hydrogen molecules.• There is an unlimited supply.
• Chain of 4 to 24 carbon atoms– carboxyl (acid) group on one end, methyl group on the
other and hydrogen bonded along the sides
• Classified – saturated - carbon atoms saturated with hydrogen – unsaturated - contains C=C bonds without hydrogen
Lipids Found in the Body
• Neutral fats – found in subcutaneous tissue and around organs.
• Phospholipids – chief component of cell membranes
• Steroids – cholesterol, bile salts, vitamin D, sex hormones, and adrenal cortical hormones
• Eicosanoids – prostaglandins, leukotrienes, and thromboxanes: – These play a role in various reactions in the body such as
inflammation and immunity.
• Lipoproteins – transport fatty acids and cholesterol in the bloodstream
• Fat-soluble vitamins – A,D, E, and K
Triglycerides
• Functions– energy storage in adipose (fat) tissue– Fats contain 9 kcal per gram where as
carbohydrates and proteins contain 4 kcal per gram.
• They contain more energy rich hydrogen.
– insulation • Prevent heat loss from the body
– protection• Adipose tissue cushions the organs.
Triglycerides (Neutral Fats)• Contain C, H, and O, but the proportion of oxygen in
lipids is less than in carbohydrates 3 • Fatty acids are bonded to a glycerol molecule during
dehydration synthesis.• At room temperature : Contain double bonds.
– when liquid called oils• often mono and polyunsaturated fats from plants
– when solid called fat• saturated fats from animals.
– No double bonds.• Function - energy storage, insulation and shock
absorption
Protein Functions– Catalysts
• proteins which are enzymes significantly increase the rate of a chemical reaction i.e. Salivary Amylase increases the rate of hydrolysis of starch.
– Structural• hold the parts of the body together i.e. collagen, elastin
and keratin – Communication
• act as chemical messengers between body areas .i.e. hormones such as insulin.
– Transport• allow substances to enter/exit cells• Carry things in the blood i.e. hemoglobin, lipoproteins,
Protein Functions
– Movement• Actin and myosin function in muscle contraction
– Defense• Antibodies( immunoglobulins) recognize and
inactivate foreign invaders( bacteria, toxins, and some viruses)
– Metabolism• Help regulate metabolic activities, growth and
development
– Regulation of pH• Plasma proteins such as albumin can function both
as an acid or a base. Therefore have an important role as a buffer
Amino Acids Structure
• Building blocks of protein• Amino and carboxyl
group groups are common in all Amino acids.
• R-group (radical group): 20 amino acids are different both structurally and from a functional level.
Protein• Macromolecules composed of combinations of 20 types of amino
acids bound together with peptide bonds• Animal ,dairy and right combination of beans and rice are good
sources of protein.• Enzymes are specific types to proteins that enable reactions.
Protein Structure• Primary structure
– amino acid linked together by peptide bonds. The order of the amino acids critical for both form and function. No hydrogen bonds formed.
• Secondary structure :The primary structure will now form hydrogen bonds and take one of 2 forms: – α helix (coiled), β-pleated sheet (folded)
• Tertiary structure– more hydrogen bonds form and increased interaction
between R groups in surrounding water results in protein taking a globular 3 dimensional shape.
• Quaternary structure– two or more separate polypeptide chains conjugate and form
a functional protein• Hemoglobin.
Structural Levels of Proteins• Primary – amino acid sequence• Secondary – alpha helices or beta pleated
sheets
Structural Levels of Proteins
• Tertiary – superimposed folding of secondary structures– Most enzymes are in this form.
• Quaternary – polypeptide chains linked together in a specific manner
Functional Proteins (Enzymes)
• Enzymes are chemically specific. They fit a specific substrate like a lock and key.
• Enzyme names usually end in –ase – for example Lactase will be specific for the substrate
lactose ( Glucose Galactose)» Gycosidic bond
• Frequently named for the type of reaction they catalyze i.e. hydrolases add water during hydrolysis reactions.
• lipase/lipids, protease/ proteins,• Act as biological catalysts which lower activation energy
allowing reactions to occur at faster rates.
Activation Energy
• Activation energy refers to the extra energy required to break an existing chemical bonds and initiate a chemical reaction.– Activation energy determines rate of reaction
(higher activation energy = slower reaction)– catalyst - substance that lowers the activation
energy by influencing (stressing) chemical bonds
Enzyme Substrate Complex
• Enzymes need their 3 dimensional structure – created by both Hydrogen
and disulfide bonds which is specific to a certain substrate.
– Proper conditions are needed to keep these enzymes functioning.
– pH – Temperature
Protein Denuaturation
• Hydrogen bonds are broken and tertiary level protein reverts back to primary structure. Peptide bonds are still intact.
Protein Denuaturation
• Proteins will become denatured if: – ∆ pH – ↑ temperature
• Hydrogen bonds are broken from complex tertiary level proteins to basic primary structure. – Peptide bonds are still
intact.• Visible changes you see
when frying an egg
Nucleic Acids
• Two major classes – DNA and RNA
• Composed of carbon, oxygen, hydrogen, nitrogen, and phosphorus
• Five nitrogen bases contribute to nucleotide structure
• Adenine (A) Thymine (T)
• Guanine (G) Cytosine (C)
• Uracil (U) replaces Thymine in RNA
NucleotidesThe structural unit of the a nucleotide is composed of • N-containing base A,T,C,G and U in RNA• Pentose sugar: Ribose, and deoxyribose • Phosphate group
Deoxyribonucleic Acid (DNA)
• Double-stranded helical molecule confined in the nucleus of the cell
• Helical shape is a result of H-bonds between a purine on one strand and a pyramidine on the other strand– A only pairs with T– G only pairs with C
• Replicates itself before the cell divides, ensuring genetic continuity
• Provides instructions for protein synthesis
Ribonucleic Acid (RNA)
• Single-stranded molecule • Made from the nucleotides that complimentary pair • A U G C• Three varieties of RNA: 1. messenger RNA: transcribe DNA and carry it out of
nucleus. 2. transfer RNA: Bring amino acids to site of protein
synthesis (ribosome). 3. ribosomal RNA: building blocks of ribosomes ,made
in the nucleolus
Adenosine Triphosphate (ATP) Adenine-containing RNA nucleotide with three
phosphate groups• Second and third phosphate groups are
attached by high energy covalent bonds• The 3rd high energy phosphate bond of ATP is
hydrolyzed producing ADP + P + energy– The cell can recycle the ADP and P back into
ATP using the energy harvested from dietary foods primarily carbohydrates and lipids.
• Source of immediately usable energy for the cell.– It is the currency that all cellular reactions
accept.