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68 Cards in this Set
- Front
- Back
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Matter is...
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Composed of atoms: Protons, electrons, and neutrons
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Protons are...
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Positively charged particles
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Electrons are...
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Fleeting, negatively charged particles of insignificant mass and cloudlike
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Neutrons are...
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Uncharged particles with a mass like protons. They supply the force to hold the atomic nucleus together. The movement and cloudlike structure of electrons prevent their collapse into the nucleus
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Atomic Number
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The number of protons in an atomic nucleus
Differentiates the elements |
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What does the atomic number represent besides the number of protons?
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Electron Number
Accounts for the different chemical reactivity of different elements |
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Atomic Mass (Weight)
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The sum of the number of protons and neutrons in the nucleus of an atom
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Isotopes
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Elements whose atoms have a different number of neutrons and thus a different atomic mass
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True / False: One isotope is usually dominant, for example, the dominant form of hydrogen is one electron, one Proton and no neutrons
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True
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What is Deuterium?
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A rare isotope also called heavy hydrogen
It's atomic weight is 2 and it's atomic number is 1 |
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What is Tritium?
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rarley occuring third isotope of hydrogen
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Is Tritium radioactive?
What does it decay into? |
Yes
It decays into a rare isotope of helium that has a molecular mass of 3 Daltons instead of 4 |
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What kind of radiation is emitted from tritium?
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A weak beta particle that requires a detector that emits a beam of light when exposed to the particle.
The Beta particle is fast moving and may be either positively or negatively charged |
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What is the radioactivity of tritium due to?
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One of its neutrons decaying into a proton and an electron to form Helium
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What is the predominant stable isotope of carbon?
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Carbon 12 which contains 6 protons and 6 neutrons
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Describe carbon 14
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Its atomic mass is 14 Daltons and has 6 protons and 8 neutrons and is both unstable and radioactive
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What is emitted from a carbon 14 atom?
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A decayed neutron creates a proton and an electron and emits a more powerful beta particle than that of tritium
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What does a Carbon 14 atom decay into?
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A Nitrogen atom containing 7 protons and 7 neutrons
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What in the upper atmosphere allows the reverse reaction of nitrogen to form Carbon 14?
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The energy from cosmic radiation carries out the reverse reaction which fuses a proton and an electron
together |
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What isotopes are usually made in a nuclear reactor?
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Phosphorus 32 which emits strong beta radiation for use in biochemistry or medicine
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What is the use of radioactive elements in biochemistry?
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to follow biochemical reactions and identify metabolic or polymer interactions
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What is the use of radioactive elements in medicine?
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They can be targeted to a cancer cell by a radioactive chemical.
Ex. Thyroxine interacting with certain tumors of the thyroid gland |
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True / False: Additional neutrons start to appear in the common isotope of heavier elements, beginning with carbon
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False: Additional neutrons start to appear starting with fluorine
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What property of electrons allows it to determine chemical properties of each element?
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Electrons are arranged in shells surrounding the nucleus. When electrons fill a shell completely the element is stable and non-reactive
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What defines a molecule?
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They are atoms that have taken part in a chemical reaction and have either lost gained or shared electrons to complete their outer shell
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What is an Ion?
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The electrically charged atomic or molecular particle that forms an electrostatic bond
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What kinds of bonds can Hydrogen form in energy producing reactions?
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Hydrogen forms a cation with chloride
Hydrogen forms anion with lithium |
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What is required for the reversal of an electrostatic bond?
What happens during this process? |
Energy is required to activate the electron to jump off of the anion to the cation
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What are cations?
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They are formed when an element or molecule loses an electron and becomes positively charged (oxidized)
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What are anions?
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They are formed when an element or molecule gains an electron and becomes negatively charged (reduced)
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Crystals are...
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electrostatically-bonded solids with a regular repeating number of ions in an electrically neutral geometric shape or crystal cell
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What is the major electrostatically-bonded solid in the body?
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Calcium Phosphate
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Amorphous solids are...
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Electrostatically-bonded solids that do not have a crystal cell
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What amorphous solids can crystallize and how?
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Proteins may crystallize if allowed to precipitate under certain conditions
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Teeth and Bone are composed of what kinds of solids?
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A complex mixture of calcium phosphate crystals around a protein matrix
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How are organic molecules formed?
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By electron sharing
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What atoms do Carbon atoms usually share electrons with?
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Other carbons, hydrogen, nitrogen, or oxygen atoms
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Water consists of what type of bonds?
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Water has a covalently bonded oxygen with two hydrogens.
Hydrogen bonding makes water liquid |
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What is the reactivity of the nucleus of a water molecule?
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8 Protons in the nucleus of the oxygen makes it electron-attracting compared with hydrogen
This makes water stable but polarized |
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What molecule has a similar polarization to that of water?
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Carbon dioxide has a carbon atom sharing its four electrons with two oxygen atoms
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What types of bonds are strongly electron withdrawing?
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The single oxygen-carbon bond in aldehydes, ketones, and carboxylic acids
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What types of atoms are less electron withdrawing in most reactions?
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Nitrogen atoms in Amines and amides
Sulfur atoms withdrawing from carbon atoms |
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What are the most common non-polar bonds?
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Hydrogen to carbon bonds are apolar and less reactive than polar bonds.
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What occurs in photosynthesis?
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Sunlight oxidizes water to molecular oxygen
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What occurs in respiration?
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Chemical reactions reduce molecular oxygen to water.
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What happens in fermentation?
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Oxygen is not involved.
Saccharolytic fermentations degrade carbohydrates to pyruvate and NADH + H+ Puruvate then gains electrons by regenerating NAD+ and being reduced to lactate |
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Where do fermentations mainly occur?
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Bacteria
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What causes caries (cavities)?
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Bacteria fermenting dietary sucrose to lactate and other acids
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What causes periodontal disease?
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Associated with bacteria in gingival pockets hydrolyzing host proteins and releasing free amino acids that are mostly fermented to ammonia and short chain fatty acids
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Bacteria have no _____ to remove ammonia.
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Urea Cycle
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What does asaccharolytic fermentation produce?
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Ammonia and short chain fatty acids
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Where is asaccharolytic bacteria found in the oral cavity?
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Beneath the gingival margin, or in crypts and deep folds of the oral mucosa
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What are the steps of bacterial fermentation?
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(1)Free amino acids are released and deaminated to ammonia while NAD is converted to NADH
(2)Conversion of Alanine to Pyruvate and Ammonia (3)Pyruvate is reduced to lactate (4)Ammonia lactate is excreted into the environment (neutral salt) |
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What are the more common end products in plaque?
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Ammonium acetate, ammonium propionate, and ammonium butyrate, ammonium salts of short chain fatty acids
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What does Ammonia do to the gingival sulcus?
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It makes it more alkaline (pH approx. 8)
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What are the outer parts of the gram negative cell structures?
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Inner plasma membrane
Cell Wall Lipid Outer membrane Outermost lipopolysaccharide (LPS) |
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_____ may shed from the surface and stimulate inflammation.
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LPS
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What is the nucleoid in the bacterial cell structure
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DNA is confined to this central region
This material is not bound by a membrane but it is visibly distinct by microscope from the rest of the cell interior |
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These give the cytoplasm of bacteria a granular appearance in electron micrographs.
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Bacterial Ribosomes
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What are Inclusion bodies?
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Denatured proteins in the cytosol of bacteria
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What does the plasma membrane provide for gram negative bacteria?
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Its lipid bilayer has proteins that mediate secretion, ion transport and nutrient uptake much like in eukaryotes
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What makes up the cell wall and capsule of the gram negative bacteria?
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Peptidoglycans (polysaccharides + protein) maintains the shape of the cell
It is also bounded by an outer membrane with attached LPS |
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What are the three shapes of a gram negative bacteria?
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Coccus (spherical)
Bacillus (rod-shaped) Spirillum (Spiral) |
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What are Pili?
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Hollow hairlike structures of protein that allow the bacteria to attach to a surface and each other so that they form a biofilm
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What allows the transfer of genomic DNA from one bacterial cell to another?
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Specialized sex pilus (pili is plural)
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What is another name for Pili?
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Fimbriae
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What are flagella and how do they work?
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Causes motility by using their long appendages in a rotation by using a "motor" found underneath the cytoplasmic membrane
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How many flagella does a bacteria have?
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One, a few or many.
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