Chemistry of Life Chapter 2
Elements Simplest form of matter Made of atoms of one type Cannot be chemically broken down into simpler substances About 117 known elements The Periodic Table of Elements Each element has unique properties
>90% of the Human Body Carbon Nitrogen Oxygen hydrogen
Elements/Atoms Atoms Smallest unit of an element Still has chemical properties of that element Examples Element oxygen oxygen atoms Element carbon carbon atoms
Subatomic Particles Subatomic particle PROTONS Position/ Charge NUCLEUS/ + Details Atomic # = # of protons # protons = # electrons (neutral element) NEUTRONS NUCLEUS/ none Atomic mass= # protons + # neutrons ELECTRONS CLOUD/ - Stay in clouds -charge attracted to + charge of protons Outermost shell electrons---chemical rxns. Inner shell electrons---held tightly
IONS Elements with a + or charge Unequal # of protons and electrons Lost electrons------- (+) charge Ca +2 Gained electrons------ (-) charge Cl 2
Elements with Isotopes same # of protons and electrons Diff # of neutrons Radioisotopes Unstable nuclei break down Release radiation Uses: Medical tagging/tracing Fossil dating
What are isotopes used for in medicine Thyroid Scan -radioactive iodine Cancerous portion-failure to uptake iodine PET radioactive medicine is tagged to a natural chemical (glucose) As tracer is broken down positrons are made Scan detects different levels of positrons
PET Scans Used for epilepsy (what part of the brain is being affected) Alzheimer s disease Cancer Heart disease
A Thyroid scan is a nuclear medicine examination that uses the emissions of gamma rays from radioactive iodine to help determine whether a patient has thyroid problems, including hyperthyroidism, cancer, or other growths. The scanner detects the location and intensity of the gamma rays emitted
Positron emission tomography (PET) scan of a person on cocaine Cocaine has other actions in the brain in addition to activating reward. Scientists have the ability to see how cocaine actually affects brain function in people. The PET scan allows one to see how the brain uses glucose; glucose provides energy to each neuron so it can perform work. The scans show where the cocaine interferes with the brain's use of glucose - or its metabolic activity. The left scan is taken from a normal, awake person. The red color shows the highest level of glucose utilization (yellow represents less utilization and blue shows the least). The right scan is taken from a cocaine abuser on cocaine. It shows that the brain cannot use glucose nearly as effectively - show the loss of red compared to the left scan. There are many areas of the brain that have reduced metabolic activity. The continued reduction in the neurons' ability to use glucose (energy) results in disruption of many brain functions.
Chemical Bonds Attraction, sharing, or transfer of outer shell electrons Energy bonds one atom to another Energy stored in the molecule, energy is released when molecule breaks apart 3 Types: Ionic Covalent Hydrogen
Ionic Bonds Transfer of electrons Sodium (Na+) + Chloride (Cl-) Sodium chloride (NaCl) Sodium Ion: Electron donated by Sodium Chloride Ion: Electron accepted by Chloride
Covalent Bonds Electrons shared Helps fill electron shells Examples H-H (H2) and H-O-H (H2O) Which of the above is a compound? Single, double, triple Polar Covalent: if UNEQUAL SHARING
Hydrogen Bonds Hydrogen atoms bonded to oxygen or nitrogen Example: Strong force between water molecules Think about surface tension
Chemical Reactions in Living Cells Help form new molecules for Cell growth Cell development Cell maintenance Allow storage or release of energy
Acids and Bases ACIDS- dissociate in H20 release H + HCl H + + Cl - BASES- Take up H+ ions OR Release OH ions NaOH Na+ + -OH
ph ph = - [log H+] ph scale = 0 14 Indicates how acidic or basic High H+ = Very Acidic = LOW ph Low H+ = Weakly Acidic = HIGH ph or Very Basic
ph of body fluids narrow range! Normal blood ph = 7.4 (slightly alkaline) Acidosis ph < 7.35 Alkalosis ph > 7.45 BUFFERS-maintain ph [H2CO3] [HCO3] carbonic acid- H+ donor Bicarbonate - H+ acceptor
Body s ph ph controls the speed of biochemical reactions low ph (too acidic) body is slowly stewing in poisonous wastes Forces body to borrow minerals from vital organs to neutralize the acid
Electrolytes Salts, acids, bases Dissociate in water Release ions Electrolyte balance affects vital organs (heart, brain etc.)
Organic Compounds Carbon atoms combined with Hydrogen Usually Oxygen also May contain Nitrogen, Sulfur, & Phosphorous
Macromolecules Macromolecule Example Carbohydrates Subunit(s) Polysaccaride Monosaccharide Lipids Fat Glycerol + fatty acids Proteins Polypeptide Amino acid Nucleic Acids DNA, RNA Nucleotide
Carbohydrates Contain Carbon, Hydrogen, & Oxygen H:O 2:1 Function: Source of Energy 3 Types : Monosaccharides (1 sugar, simple) Disaccharides (2 sugars, simple) Polysaccharides (Multiple sugars, complex)
Monosaccharides 3-7 Carbons Simplest form: glucose
Disaccharides Double sugar Know 3 types: Sucrose(table sugar)= glucose + fructose Lactose(milk sugar) = glucose+galactose Maltose(malt sugar)=glucose + glucose
Polysaccharides Many glucose molecules Complex Carbohydrates Examples Starch Glycogen Cellulose Pectin chitin
Lipids Fats and Oils Contain carbon, hydrogen, and oxygen Not in fixed ratio Fatty acid + glycerol TG(Fat) + H2O Non-polar (do not dissolve in water) Functions: Long-term energy and carbon storage Parts of cell membrane
Types of Fats Saturated: Butter and lard, solid at room temp Single bonds only Unsaturated: Olive oil, corn oil etc, liquid at room temp Some double or triple bonds Phospholipids : form cell membrane Cholesterol: hormone development, cell membrane
Proteins Made of Amino Acids Functions Structural components of cell Messengers Receptors (receive messages) Defense Enzymes (help with cellular reactions)
Amino Acids Contain carbon, hydrogen, oxygen, nitrogen Building blocks of proteins
Peptide Bond Bond amino acids together to make protein!
Protein Structure Primary: Long polypeptide chain Secondary: folded long polypeptide chain Tertiary: more complex folding Globular or spiral structure Determined by amino acid sequence Determines function Quarternary: combined tertiary
Enzymes Are a type of protein Speed up chemical reactions (ex: lactose)
DNA and RNA Stores genetic info Contains info to make protein for the body. Nucleic Acids
Nucleic Acid Structure Made of nucleotides (4 possibilities) Each nucleotide has 3 parts: 5-carbon sugar (pentose) A phosphate group A nitrogen base (more on this )
Nitrogen Bases Purines (2 Rings): Adenine (A) Guanine (G) Pyrimidines (1 Ring): Cytosine (C) Thymine (T) replaced in RNA by Uracil (U)
DNA Deoxyribonucleic acid Double helix Each helix/strand is made of: Nucleotides Each DNA nucleotide has: A 5-carbon sugar (deoxyribose) A phosphate group A nitrogen base (A, T, G, C)
DNA Base Pairing Hydrogen bonds A and T (double bond) G and C (triple bond) Bonding b/w nitrogen base Sugar phosphate backbone
RNA Ribonucleic acid Single stranded Each strand is made of nucleotides Each nucleotide is made of: A ribose sugar A phosphate group A nitrogen base (A, U, G, C)
ATP adenosine triphosphate A nucleic acid that stores energy contains 3 phosphate groups Made in the mitochondria of every cell as it carries out cellular respiration Cells need energy from ATP to make carbs/proteins, for muscle contraction and for nerve impulse conduction