Chapter 2 - Chemical level Flashcards
What are the 4 major elements (96% of body mass) in the body?
Oxygen (O), Carbon (C), Hydrogen (H), Nitrogen (N)
What are the 8 lesser elements (3.6% of body mass)?
Calcium (Ca), Phosphorus (P), Potassium (K), Sulfur (S), Chlorine (Cl), Magnesium (Mg), Iron (Fe), and Sodium (Na)
How many trace elements are in your body?
14
How many electrons do the first 3 shells hold?
First holds 2, second holds 8 and third holds 18
Why is an atom usually electrically neutral?
Because the number of protons equals the number of electrons
Atomic number vs. mass number?
Atomic #: number of protons.
Mass #: number of protons + neutrons
All atoms of the same element will always have the same atomic number
What are isotopes?
Atoms that have different numbers of neutrons so have different mass numbers
Stable isotope vs. Radioactive isotope?
Stable - nuclear structure doesn’t change over time.
Radioactive - unstable, spontaneously change into a stable configuration
Explain how radioactive isotopes can be harmful
They can break apart molecules thus posing a threat to human body by producing tissue damage or causing various types of cancer
Name some benefits of radioactive isotopes
For diagnostic or treatment purposes. Used as tracers to follow movement of certain substances through the body.
Ex. Iodine-131 detects cancer of thyroid gland
What is the Atomic Mass?
Average mass of all its naturally occurring isotopes. Measured in Daltons and is usually close to the mass number
Define ion and ionization
Ion: - + or - atoms because it has unequal # of protons & electrons
Ionization: Process of giving up/gaining elections symbolized by (+) or (-)
Define:
- molecule
- compound
- free radical
Molecule: 2 or more atoms share electrons (ex. H2O or O2)
Compound: substance of 2 or more molecules of different elements (Ex. H20, NaCl)
Free radical: Atom or group of atoms with unpaired electron in outermost shell (unstable, highly reactive); becomes stable by giving up or taking an electron from another molecule
Define chemical bonds - what increases likelihood of chemical bonds?
Chemical bonds hold together atoms of a molecule or compound
Atoms who do not have a filled valence shell are more likely to form a bond
What is the Octet Rule?
Explains why atoms act in predictable ways. One atom will be more likely to bind with another if doing so will leave both of them with 8 electrons in its valence shell
What are the 3 types of chemical bonds?
Ionic, covalent, and hydrogen
Define an ionic bond (cation vs. anion)?
Holds together 2 ions with opposite charges
During a bond it either looses/gains electrons to become:
Cation: positively charged ion (protons exceed electrons)
Anion: negatively charged ion (electrons exceed protons)
What’s an electrolyte?
Ionic compound that breaks apart into positive and negative ions in a solution… the solutions conduct an electrical current
Define covalent bond?
Two or more atoms SHARE electrons rather than gaining or losing them.
Share either 1 (single -), 2 (double =), or 3 (triple ≡) pairs of valence electrons; the more pairs, the stronger the bond
Non-polar vs. Polar covalent bond?
Non-polar: atoms share electrons equally
Polar: atoms share electrons unequally; the atoms that attracts more strongly has greater electronegativity (partial - charge) and the other will have partial + charge
Define hydrogen bonds?
H atom with a partial + charge attracts the partial negative charge of neighbouring electronegative atoms.
Results from attraction of oppositely charged parts of molecules rather than from sharing electrons (covalent) or loss/gain of electrons (ionic)
What gives a hydrogen bond high surface tension?
H that binds with water molecules creates high surface tension, a measure of difficulty of stretching or breaking the surface of a liquid
Define chemical reaction
Occurs when new bonds are formed or old bonds break between atoms
Reactants - starting substances
Products - ending substances
What is a catalyst?
Chemical compounds that speed up chemical reactions by lowering the activation energy needed and helping them collide
Enzymes are important catalysts
Explain the basic differences between synthesis, decomposition, exchange, reversible, and oxidation-reduction reactions
Synthesis: put together larger molecules (anabolism refers to all synthesis reactions in the body)
Decomposition: split up molecules (catabolism refers to all decomposition reactions in the body)
Exchange: consist of both synthesis and decomposition; switching partners (ex. AB+CD -> AD+BC)
Reversible: Products can refer to optical reactants (ex. AB A+B)
Oxidation-reduction: concerned with transfer of electrons between atoms (one substances is oxidized and the other is reduced); oxidation (loss of elections) releases energy and reduction (gain of electrons) gains energy
Inorganic vs. organic compounds?
Inorganic: lacks carbon, structurally simple (water, salts, acids, bases)
Organic: contains carbon
Water is the most important and abundant ______ compounds in all living systems. Its more important property is its _______, the uneven sharing of valence electrons that makes it an excelled slant, gives cohesion, and allows resistance to temp
Inorganic; polarity
Define solvent & solute (hydrophilic vs. hydrophobic)? Why is water a good solvent?
A solvent dissolves another substances called the solute
Solutes that are charged/contain polar covalent body are hydrophilic = dissolve easily
Solutes containing mainly non-polar covalent bonds are hydrophobic = not very soluble
Water makes a good solvent for hydrophilic solutes due to its polarity and bent shape
Water can participate as a reactant or product in certain chemical reactions. Compare hydrolysis & dehydration synthesis reactions?
Hydrolysis (decomposition reaction): uses water as a reactant to break down molecules enabling nutrients to be absorbed into the body
Dehydration synthesis reaction: a synthesis reaction where a water molecule is one of the products formed
Thermal properties of water. Define high heat capacity?
Can absorb/release large amount of heat with only a modest change in temperature due to large number of H bonds
Water is a lubricant - why is lubrication important?
It is necessary where organs touch and slide over one another - mucus and water recreation aids in smooth passage
Define mixture and the three common liquid mixtures (solutions, colloids, suspension)?
Mixture: combination of elements/compounds that are physically blended by not bound
Solutions: solutes remain evenly dispersed and appear transparent due to small particles
Colloids: solute particles are larger and scatter light and appear translucent or opaque
Suspension: suspended material mix with the liquid for some time but eventually settle out
How is the concentration of a solution expressed?
- Mass/volume %
2. Moles/litre (molarity): A mole is the sum of the atomic masses in g ex. (22.99Na+35.45Cl) 1 mole of NaCl = 58.44g
When inorganic acids, bases, or salts dissolve in water they dissociate, separating into ions. What is the difference between an acid, base and salt?
Acid: dissociated into one or more hydrogen ions (H+) and one or more anions
Bases: removes H+ from a solution and dissociates into one or more hydroxide ions (OH-)
Salt: dissociates into cations and anions, neither which is H+ or OH-
Define the pH scale. What makes a solution or acidic or basic (alkaline)?
pH scale: a solutions acidity or alkalinity that extends from a 0-14 scale; 7 indicates H+ and OH- are equal (below 7 = acidic; above 7 = basic)
The more H+ dissolved, the more acidic; the more OH- dissolved, the more basic
Define a buffer system (acidosis vs. alkalosis)?
A buffer system functions to covert strong acids/bases into weak acids/based to maintain homeostasis
pH of blood must maintain levels between 7.35 and 7.45
- Acidosis: pH falls below 7.35
- Alkalosis: pH rises above 7.45
What is the carbonic acid-bicarbonate buffer system?
Carbonic acid (H2CO3) can act as a weak acid and bicarbonate ion (HCO3-) can act as a weak base
Thus, this buffer system can compensate for either excess/shortage of H+
Define carbohydrates
Includes sugars, glycogen, starches, cellulose.
Function as a source of chemical energy for generating ATP needed to drive metabolic processes
C, H and O are elements of carbohydrates (2:1 ratio of H to O)
Define the 3 main groups of carbohydrates?
Monosaccharides: simple sugars that contain 3-7 carbon atoms (ends in -ose: glucose, fructose, galactose, etc.)
Disaccharides: simple sugars formed from combination of 2 monosaccharides by dehydration synthesis (ex. sucrose= glucose + fructose; lactose= glucose+galactose)
Polysaccharides: tens-hundreds of monosaccharide joined by dehydration synthesis; usually insoluble in water
Starch, cellulose, and glycogen are examples of _________ carbohydrate group. Explain them
Polysaccharides
Starch - stored from carbs in plants & main carb in food
Cellulose - part of cell wall in plants that cannot be digested by humans but aids in movement through intestine
Glycogen - stored form of carbs in animals
Define macromolecules, polymers, monomers, and isomers
Macromoleules: combination of organic molecules
Macromolecules are usually polymers, a large molecule formed by bonding of many small and similar molecules called monomers
Isomers: molecules with the same molecular formula but different structures
What are the 3 types of subatomic particles important for understanding chemical reactions in the body?
Protons: positively charged, within nucleus
Neutrons: uncharged, within nucleus
Electrons: negatively charged, surround nucleus
Define lipids & lipoproteins
Insoluble in polar solvents (hydrophobic0 due to less electronegative O atoms resulting in fewer covalent bonds
C, H and O are elements of lipids (does not have 2:1 ratio of H to O)
In order to become soluble in blood plasma they join hydrophilic molecules to become lipoproteins
Describe the function of the following lipids:
- fatty acids
- triglycerides
- phospholipid
- steroid (cholesterol)
- eicasnoids
Fatty acids: synthesize triglycerides and phospholipids or catabolized to generate ATP
Triglycerides (fats & oils): protections, insulation, energy storage
Phospholipid: major lipid component of cell membranes
Cholesterol (steroid): minor comment of animal cell membrane, precursors of bile salts, Vit D, and steroid hormones
Eicasnoids (proglandins & luekotrine): diverse effects on modifying responses to hormones, blood clotting, inflammation, immunity, stomach acid secretion, smooth muscle contraction
Saturated vs. unsaturated fatty acid
Saturated: contains only one single covalent bond between carbon atoms and hydrocarbon chain
Unsaturated: contains one or more double covalent bonds between the carbon atoms of the hydrocarbon chain (has a kink/bend)
Describe the structure of the following lipids:
- fatty acids
- triglycerides
- phospholipid
- steroid
Fatty acids: carboxyl group and hydrocarbon
Triglycerides: single glycerol molecule and 3 fatty acid molecules
Phospholipid: 2 fatty acid chains that attach to the first 2 carbons in the glycerol backbone and phospage groups links a small charged group to the third carbon
Steroid: 4 rings are carbon atoms
Phospholipids have both polar and non-polar parts which are known as __________
amphipathic - they line up tail-to-tail in a double row to make a membrane
Describe the function of the following proteins:
- Structural
- Regulatory
- Contractile
- Immunological
- Transport
- Catalytic
Structural: form structural framework for body
Regulatory: function as hormones that regulate various physiological processes; control grown; as NTs mediate response of NS
Contractile: allow shortening of muscle cells (movement)
Immunological: Aid responses that protect body against pathogens
Transport: transport vital substances
Catalytic: act as enzymes to regulate biochemical reactions
Define proteins
Large molecules that contain C, H, O, and N and some contain S
They are structurally more complex than carbs or lipids and are largely responsible for the structure of body tissues
Define amino acids & peptide bonds
Amino acids - monomers that make up proteins (20 types)
Peptide bonds - amino acids are bonded by covalent bonds to create a protein
Peptide proteins can be in combinations of 2 (dipeptide), 3 (tripeptide), 4-9 (peptide), and 10+ (polypeptide)
Describe the 4 levels of structural organization in proteins (primary, secondary, tertiary, quaternary)
Primary: unique sequence of amino acids
Secondary: repeated twisting/folding of neighbouring amino acids
Tertiary: 3-dimensional shape of polypeptide chain
Quaternary: arrangement of polypeptide chain relative to one another (only in proteins with 1+ polypeptide chain)
Fibrous vs globular proteins
Fibrous - insoluble in water and polypeptide chains run parallel to each other (structural functions)
Globular - more soluble and peptide chain are spherical (metabolic functions)
_________ refers to the process in which a protein encounters an altered environment causing it to unravel and lose its characteristic shape
Denaturation (no longer functional)
Define nucleic acids and their 2 varieties
Huge organic molecules that contain C, H, N, and P
It is a chain of repeating monomers called nucleotides
DNA: forms inherited genetic natural inside each cell
RNA: relays instructions from genes to guide each cell’s synthesis of proteins from amino acids
Describe the 3 parts of a DNA nucleotide:
Nitrogenous base: 4 different bases [adenine (A) & thymine (T), cytosine (C) & guanine (G)]
Pentose sugar: 5-carbon sugar called deoxyribose attaches to each base
Phosphate group
Compare the sugars in nuclotides and number of strings between DNA and RNA
DNA: deoxyribose (sugar), double helix (strands)
RNA: ribose (sugar), single stranded)
ATP vs. ADP
ATP: energy of living systems - transfers energy liberated in exergonic catabolic reactions to power cellular activities
ATPase hydroysizes ATP: H20 + ATP –> ADP + P + energy
Describe the 3 part mechanism of an enzyme
Enzyme and substate (reactant molecules) come together at active sit of enzyme, forming an enzyme-substrate complex
Enzyme catalyzes reaction and transforms substates into products
When reaction is complete the enzyme is unchanged and free to catalyze same reaction again on a new substate
