UNIT 1 - CHEMISTRY OF LIFE Flashcards
what is matter?
-anything that has mass and takes up space
what are the 4 main states of matter?
-solid
-liquid
-gas
-plasma
what is plasma? is it found in the human body?
-ionized gas (electrons are ripped away)
-composes the visible universe
-not in the human body
what are elements?
-building blocks of matter
-cannot be broken down by chemical means
what elements make up over 90% of the human body?
-oxygen
-carbon
-hydrogen
-nitrogen
what is an atom?
-smallest unit of an element
-retains the elements physical and chemical properties
-bond together to form molecules
what are the subatomic particles found within an atom?
-neutron (nucleus)
-proton (nucleus)
-electron (electron shells)
how many elements are found in the universe? how many occur naturally?
-118
-98 naturally
what elements are components of major biomolecules?
-hydrogen
-carbon
-oxygen
-nitrogen
-phosphate
-sulfur
what elements are responsible for fluid balance and nerve transmission?
-potassium
-sodium
-chlorine
-SALTS
what elements are necessary for bones and nerve function?
-calcium
-magnesium
what elements are essential for human metabolism and in small quantities?
-zinc
-strontium
-iron
-copper
-cobalt
-manganese
what heavy metal elements are toxic to living systems?
-mercury
-lead
-cadmium
what are chemical properties linked to?
-atomic structure and shape
what are the groups and periods of the periodic table? what do they represent?
-groups = vertical = same # of valence electrons
-periods = horizontal = # of electron shells/energy levels
what does the atomic number signify?
-the number of protons
-denoted by Z
what does the mass number signify?
-sum of protons and neutrons
-denoted by A
what is the atomic mass?
-the average AMU for all isotopes of that atom
what are isotopes?
-atoms of the same element that have different numbers of neutrons
-differ in atomic mass
what are radioisotopes?
-unstable isotopes that emit energy (radiation)
what is radiations function and what is it used for?
-can damage cells and cause cancer
-uses to image the body, kill bacteria in food, sterilize equipment, and kill cancer cells
what are 2 examples of medical uses for radiation? what elements/isotopes does each example use?
-thyroid scintigraphy (iodine)
-brain pet (positron emission tomography) (fluorine + glucose)
how many energy levels/shells are there?
-7
-denoted as the following with the max # of electrons occupying
-K (2)
-L (8)
-M (18)
-N (32)
-O (32)
-P (18)
-Q (8)
what are the sublevels of the electron shells? how many electrons occupy each?
-S (2) (sharp)
-P (6) (principal)
-D (10) (diffuse)
-F (14) (fundamental)
how do electrons move around the nucleus? do we know their exact position?
-with varying energy levels and configurations
-do not know the exact position, but have a general idea
what is atomic radius?
-distance from the nucleus to the boundary of an electron shell
what is ionization energy?
-the amount of energy required to remove an electron
what is electron affinity?
-the amount of energy released when an electron is attached
what does metallic character mean?
-tendency to lose electrons during chemical reactions
-left side of the periodic table
what does non-metallic character mean?
-tendency to accept electrons during chemical reactions
-right side of the periodic table
what are molecules?
-atoms bonded together
-can be the same or different atoms
what are compounds/
-molecules made of different atoms
when are atoms most stable? how do they reach this point? what results?
-when their valence shell is full
-donate or take on electrons (ionic reaction)
-share electrons (covalent)
-positive or negative ions are formed
what is an ionic bond?
-the attraction between a positive and negative ion (metal and non-metal)
what is a covalent bond?
-atoms share electrons
-each atom contributes one electron to the shared pair and electrons spend time in both valence shells
-double bond (2 shared pairs)
-triple bond (3 shared pairs)
what is the most abundant molecule in organisms? what is the approximate abundancy?
-water
-60-70% of total body weight
is water a polar or nonpolar molecule? what does this mean?
-polar molecule
-electrons are more attracted to oxygen than hydrogen (higher electronegativity)
-a partial negative charge is created about the oxygen
-a partial positive charge is created about the hydrogen
what is a hydrogen bond?
-attraction between a slightly positive hydrogen to a slightly negative oxygen or nitrogen
-depicted by dotted lines
-pH and temp sensitive (changes structure)
-bonds are critical to shape (bonds are considered weak)
why are hydrogen bonds between water molecules important?
-give special properties
-liquid at room temperature
-high heat capacity (lots of energy to change temp)
-high heat of vaporization (hydrogen bonds need to break for water to vaporize) (lots of energy to change states)
what is a calorie?
-the amount of heat required to raise one gram of water one degree celsius
why is water having a high heat capacity important?
-prevents large temperature changes in the body
why is water having a high heat of vaporization important?
-allows sweating to cool us off
-the large amount of energy needed to break the hydrogen bonds gets released as heat from the body
why is water important as a solvent?
-dissolves many substances
-facilitates many chemical reactions (breaking of ionic bonds when in the presence of a polar water molecule)
why is it important that water is polar in terms of being a solvent?
-polar molecules will attract water (hydrophilic)
-nonpolar molecules will repel water (hydrophobic)
-waters polarity allows it to break the bonds of other substances, causing them to dissolve
-nonpolar molecules will not have a charge and therefore not dissolve or be attracted to water
what is cohesion?
-water molecules cling together through hydrogen bonds (no discontinuity because of the bonds)
-water can flow freely without separating (high surface tension)
what is surface tension in water?
-water molecules on the surface do not have bonds above them (only below and beside)
-the lack of bonds above creates a stronger bond with the molecules beside and below
-ex: helps things float
what is adhesion?
-water molecules cling to other polar molecules or surfaces (blood vessels)
-adhesive forces can overcome cohesive forces (capillary action)
what are acids?
-substances that dissociate in water and release hydrogen (H+) ions
ex: HCL in the stomach for digestion
what are bases?
-substances that take up free hydrogen ions (H+) or release hydroxide ions (OH-)
-ex: NaOH is a strong base (catches protons)
what is the pH scale?
-measure of acidity or basicity (alkalinity) of a solution
-ranges from 0-14
-7 is neutral ([H+] is = to [OH-])
-below 7 is acidic ([H+] is greater than [OH-])
-above 7 is basic ([OH-] is greater than [H+])
-[H+] changes by a factor of 10 (pH 7 means 10^-7 mol/L)
what is a buffer?
-a solution that resists changes in pH when acids or bases are added to it
-helps to create only small changes in pH
-ex: carbonic acid or bicarbonate ions in blood
why are buffers important? how do they act in the blood?
-help the body or ecosystem keep a narrow pH range
-absorb H+ and OH- produced by metabolism to prevent pH changes
what is the ideal pH of blood?
-7.35-7.45
what happens when the blood goes below a pH of 7.35? how is this counteracted?
-acidosis
-blood is acidic (high [H+])
-the respiratory system (lungs) releases more CO2 (quick effect)
what happens when the blood goes above a pH of 7.45? how is this counteracted?
-alkalosis
-blood is basic (low [H+])
-the renal system (kidney) excretes more H+ ions and conserves bicarbonate ions (HCO3-) (long effect)
what are the 4 major organic molecules in the body?
-carbohydrates
-lipids
-proteins
-nucleic acids
what defines a molecule as organic?
-contains hydrogen and carbon (emphasis on carbon)
-has subunits
-formed and dissociated through dehydration and hydrolysis reactions
what is a dehydration reaction?
-a synthesis chemical reaction that removes water in order to link subunits together into macromolecules
-anabolic reaction (JOINS)
what is a hydrolysis reaction?
-the addition of water to break macromolecules into their subunits
-catabolic reaction (SEPARATES)
what is the purpose of carbohydrates?
-energy source
-energy storage (liver + muscle)
what makes up a carbohydrate?
-carbon
-hydrogen
-oxygen
-H:O is 2:1
-general formula is Cm(H2O)n (m and n are subscripts)
what are the 3 types of carbohydrates?
-monosaccharides
-disaccharides
-polysaccharides
what is a monosaccharide? what is an example?
-single sugar molecule
-carbon backbone of 3-7 carbons
-pentose = 5
-hexose = 6 (glucose is most common)
what is glucose used as?
-an immediate energy source in the body
what is a structural isomer?
-same chemical formula but different arrangement of atoms
what is a disaccharide? what are examples?
-2 monosaccharides joined by a dehydration reaction
-sucrose and lactose
what is a polysaccharide? what are examples?
-long polymers of glucose subunits
-complex carbohydrates
-glycogen (humans), starch + cellulose (plants)
where is glycogen stored?
-in the liver
what are lipids? what are the different forms?
-lipids are fats
-5 forms are fatty acids, triglycerides (fats + oils), wax, phospholipids, and steroids
what are the properties of lipids?
-do not dissolve in water (lack hydrophilic polar groups)
-diverse in their function and forms
what are fatty acids?
-long chains of carbons and hydrogens
-end in COOH
-most contain 16-18 carbons
-saturated or unsaturated
what makes a saturated fatty acid?
-no double covalent bonds between carbons
-saturated with hydrogen
-solid at room temp.
-not healthy
-ex: butter
what makes an unsaturated fatty acid?
-have one or more double covalent bonds because hydrogens are missing
-liquid at room temp
-ex: oil
why do unsaturated fatty acids have bends in their carbon chains?
-lack of hydrogen atoms + double bonds
-missing hydrogens on the same side
what can saturated fatty acids contribute to?
-atherosclerosis
-disease of the blood vessels
what are trans fats?
-man made
-contribute to heart disease more than other fatty acids
-are unsaturated
what is different about the missing hydrogens of trans fats?
-the missing hydrogens are on opposite sides of the carbon chains
what is the role of fatty acids?
-part of phospholipids (structure), build the cell membrane
-storage material in cells
-derivatives involved in cell signalling
what makes a triglyceride? what are its forms?
-one glycerol and three fatty acids
-2 forms (fats and oils)
-fats (animal, solid at room temp.)
-oils (plant, liquid at room temp.)
what are the functions of triglycerides?
-energy storage
-insulation
-cushioning
what are the properties of triglycerides?
-mainly hydrophobic (clump in body fluids)
-need to be emulsified (ex: allows enzymes to break them down)
what makes wax? what is its purpose?
-one fatty acid attached to an alcohol
-solid at room temp.
-prevent the loss of moisture from body surfaces
-ex: more lipid content in wet rather than dry ear wax
what makes up phospholipids?
-similar structure to triglycerides
-2 fatty acids with a polar phosphate group
-polar hydrophilic head
-nonpolar hydrophobic tails
-can be saturated or unsaturated depending on the fatty acid tails
what is the purpose of phospholipids?
-primary components of the plasma membrane (forms a bilayer)
-hydrophilic heads face watery solutions in and around cells
-hydrophobic tails face away
what makes up steroids? what differs them?
-four fused carbon rings
-differs in the functional group attached to the rings
what is an important steroid? what other steroids does it act as a precursor to?
-cholesterol
-component of membranes
-precursor to sex hormones (estrogen + testosterone)
what are the functions of proteins?
-support (keratin for hair + nails, collagen for ligaments + skin)
-enzymes (speed chemical reactions)
-transport (channel + carrier proteins, blood transport molecules (steroid binding proteins))
-defense (antibodies bind foreign substances (antigens) to disable them)
-hormones (chemical messengers)
-motion (contractile proteins (actin and myosin) move and contract muscles)
what is a peptide bond?
-polar covalent bond between two amino acids
what are amino acids? what are its components?
-subunits of proteins
-an amino group, carboxyl group, and an R (functional) group
-R group is specific to each amino acid
what is a polypeptide?
-three or more amino acids linked together
what is the denaturation of a protein?
-the change in shape of a protein
-caused by extreme heat or pH
-disrupts the proteins function
what are the levels of protein organization? which level do not all proteins have?
-primary, secondary, tertiary, quaternary
-not all have quaternary
what creates a proteins shape?
-hydrogen bonding between amino acids
what is primary protein structure?
-the linear order of amino acids
what is secondary protein structure?
-localized folding
-alpha helix or beta sheet
what is tertiary protein structure?
-proteins 3-D shape
-determined by all three bond types (covalent, ionic, hydrogen)
what is quaternary protein structure?
-combination of more than one polypeptide
-each polypeptide has individual primary, secondary, and tertiary structure
what are nucleic acids?
-polymers of nucleotides
-what makes up a nucleotide?
-phosphate, 5 carbon sugar, and a nitrogenous base
what are the functions of nucleic acids?
-store information (DNA)
-contain instructions for essential activity (mRNA)
-conduct chemical reactions (interference RNA)
-structural (ribosomal RNA)
do all cells have the same DNA? what is the purpose of DNA?
-YES
-stores info on how to copy itself + specifies the order of amino acids in proteins
what is the purpose of RNA?
-various types with many functions
-tRNA, mRNA, rRNA, microRNA, and some are coenzyme components (regulate enzyme action)
what is a nucleoside?
-nucleotide without a phosphate
-just the nitrogenous base and 5 carbon sugar
what makes the backbone of DNA (and some RNA)? where do the bases project?
-alternating phosphate and sugar
-to one side of the backbone
what is important about DNA’s structure?
-double stranded
-two strands form a double helix held by hydrogen bonds between bases
-strands are antiparallel (run in opposite directions)
-elongation at the 3’ end for polymerases
what is complementary base pairing? what can this be linked to?
-adenine > thymine/uracil
-cytosine > guanine
why are DNA strands antiparallel?
-position of carbon molecules on the deoxyribose sugar molecules
how is ATP formed?
-bond breaking between the 2nd and 3rd phosphates releases energy (used in other chemical reactions)
-ADP is formed
-a free phosphate is added to form ATP
-ATP is very high energy
