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123 Cards in this Set
- Front
- Back
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Chemical elements
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= building blocks that make up all forms of living and non-living matter
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What are the 4 major chemical elements in the body?
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O, C, H, N
96% of body's mass |
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What are the 8 lesser chemical elements in the body?
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Ca, P, S, K, Na, Cl, Mg, Fe
3.8% of body's mass |
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Trace elements (14 total)
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aluminum (Al), boron (B), chromium (Cr), cobalt (Co), copper (Cu), fluoride (F), iodine (I), manganese (Mn), molybdenum (Mo), selenium (Se), silicon (Si), tin (Sn), vanadium (V), zinc (Zn)
"ABCCC FIMMSSS VZ" 0.2% of body's mass |
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Describe the basic structure of an atom
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- protons and neutrons make up the nucleus
- electrons orbit around the nucleus along electron shells - 1st electron shell holds 2 - 2nd electron shell holds 8 - 3rd electron shells holds 18 |
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What is an ion?
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= an atom that has lost or gained an electron and thus, has a positive or negative charge due to an unequal number of protons and electrons
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What is ionization?
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= the process of giving up or gaining electrons
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Describe the basic structure of an ion
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An atom with lost or gained electrons.
Ex. Ca2+ has 2 positive charges because it has lost 2 negative charges |
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Describe the basic structure of a molecule
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A molecule is the result of 2 or more atoms sharing electrons.
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Describe the basic structure of a compound
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A compound = a substance that contains 2 or more different elements.
Ex. 02 (Oxygen2 is not a compound because it contains only 1 element); H20 is a compound because it contains 2 different elements |
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Describe the basic structure of a free radical
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A free radical = an electrically charged atom or group of atoms with an unpaired electron in the outermost shell (aka. valence shell).
Ex. superoxide Fig 2.3 |
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What is the effect of an unpaired electron?
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- makes up a free radical molecule
- makes it unstable, highly reactive and destructive to nearby molecules |
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How does a free radical become stable again?
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By giving up their unpaired electron to, or taking on an electron from, another molecule.
Therefore, free radicals may break apart important body molecules. |
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Define: Chemical bonds
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= the forces that hold together the atoms of a molecule or a compound
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Explain how ionic bonds are formed
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Formed when a cation (a positively charged ion) and anion (a negatively charged ion) are attracted to one another.
"Opposites attract" Ex. Na+ and Cl- --> NaCl |
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What is an electrolyte?
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= an ionic compound that breaks apart into positive and negative ions in solution
- Most ions in the body are dissolved in body fluids as electrolytes, so named bc their solutions can conduct electric currents |
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Explain how convalent bonds are formed
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When two or more atoms share 1, 2, or 3 pairs of valence electrons (rather than gaining or losing electrons).
- the larger the number of electrons pairs shared between two atoms, the stronger the covalent bond. - covalent bonds may form between atoms of the same element or between atoms of different elements. - most common chemical bonds in the body; therefore, the compounds formed by covalent bonds form most of the body's structures. Double covalent bond = when two atoms share two pairs of electrons. - Single and triple |
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What is a nonpolar covalent bond?
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= a bond that results from 2 atoms sharing electrons equally - one atoms does not attract the shared electrons more strongly than the other atom.
Ex. bonds between two identical atoms. H2, O2, N2. Fig 2.5a-c Ex. bonds between C and H atoms. CH4. Fig 2.5d |
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What is a polar covalent bond?
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= a bond that results when the sharing between 2 atoms is unequal - the nucleus of one atom attracts the shared electrons more strongly than the nucleus of the other atom.
- A molecule with this bond has a partial negative charge (d-) near the atom that attracts electrons more strongly (aka. greater electronegativity). At least one other atom in the molecule will have a partial positive charge (d+). Ex. H2O Fig 2.5e *electronegativity = the power to attract electrons to itself. |
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Explain how hydrogen bonds are formed
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Forms when a hydrogen atom with a partial positive charge attracks the partial negative charge of neighboring electronegative atoms, most often oxygen or nitrogen atoms.
In other words, hydrogen bonds result from attraction of oppositely charged parts of molecules rather than sharing of electrons as in covalent bonds, or the loss or gain of electrons as in ionic bonds. |
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What are the 3 different types of chemical bonds from weakest to strongest?
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Hydrogen < ionic < covalent
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Define: Chemical Reaction
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= the foundations of all life processes due to the interactions of valence electrons.
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How does a chemical reaction occur?
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- when new bonds form or old bonds break between atoms.
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Define: metabolism
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= all the chemical reactions occurring within the body
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What are catalysts?
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= chemical compounds that speed up chemical reactions by lowering the activation energy needed for a reaction to occur. Fig 2.9
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Define: synthesis reaction
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= the process of two or more atoms, ions, or molecules combining to form new and larger molecules
A + B ---> AB |
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Define: anabolism
Give an example |
= the term that collectively refers to all the synthesis reactions int he body.
= simple molecules combining to form large molecules Ex. amino acids forming proteins |
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Anabolic reactions are endergonic, which means?
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- they absorb more energy than they release.
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Define: decomposition reaction
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= a process that splits up large molecules into smaller atoms, ions, or molecules.
AB ----> A + B |
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Define: catabolism
Example? |
= the term that collectively refers to all the decomposition reactions that occur in your body
Ex. the break-down of glucose to pyruvic acid with the net production of 2 molecules of ATP |
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Catabolic reactions are exergonic, which means?
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- they release more energy than they absorb
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Define: exchange reaction
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= a reaction that consists of both synthesis and decomposition reactions.
AB + CD ---> AD + BC HCl + NaHCO3 ---> H2CO3 + NaCl |
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Define: reversible reaction
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= a reaction in which the products can revert to the original reactants.
- some reactions are reversible only under specific conditions |
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What is the importance of enzymes in reversible reactions?
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- many reversible reactions require enzymes
- often, different enzymes guide the reaction in opposite directions |
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Define: Inorganic compounds
Examples? |
= compounds that usually lacks carbon and are structurally simple.
Ex. water and many salts, acids, and bases. |
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What kinds of bonds do inorganic compounds have?
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- either ionic or covalent bonds
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Inorganic compounds make up how much of body mass?
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55–60% water
1–2% all other inorganic compounds combined |
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Give 3 examples of inorganic compounds that DO contain carbon:
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carbon dioxide (CO2)
bicarbonate ion (HCO3-) carbonic acid (H2CO3) |
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Define: organic compounds
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= compounds that always contain carbon, usually contain hydrogen, and always have covalent bonds
- most are large molecules - many made up of long chains of carbon atoms |
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Organic compounds make up how much body mass?
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38–43%
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Why is polarity such an important property of water?
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- makes water an excellent solvent for other ionic or polar substances
- gives water molecules cohesion (the tendency to stick together) - allows water to resist temperature changes "SCT" (solvent, cohesion, temperature change resistance) |
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Define: hydrophilic
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= the ability to dissolve easily in water.
Solutes that are charged or contain polar covalent bonds. |
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Define: hydrophobic
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= not very water-soluble
Molecules that contain mainly nonpolar covalent bonds |
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How does water participate in chemical reactions?
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- acts as a reactant and product in certain reactions.
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Define: hydrolysis
Ex. What is a bodily process that uses this type of reaction? |
= a type of reaction in which the addition of water breaks apart larger molecules into smaller molecules.
Ex. Digestion - this decomposition reaction of breaking larger nutrient molecules down into smaller nutrient molecules is possible due to the the addition of water |
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Define: dehydration synthesis reaction
Ex. What is a bodily process that uses this type of reaction? |
(de- = from, down, or out; hydra- = water)
= a type of reaction in which two smaller molecules join together to form a larger molecule and water is one of the products formed. Ex. Synthesis of proteins and other larger molecules |
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How is the heat capacity of water compared to other substances?
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- water has a high heat capacity. It can absorb or release a relatively large amount of heat with only a modest change in its own temperature.
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Explain how water has high heat capacity.
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As water absorbs heat energy, some of the energy is used to break hydrogen bonds (and there are a a lot of hydrogen bonds in water).
Less energy is then left over to increase the motion of water molecules, which would increase the water's temperature. |
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Why is water used in automobile radiators?
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it cools the engine by absorbing heat without its own temperature rising to an unacceptably high level
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Why is the high heat capacity of water so important for our bodies?
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It lessens the impact of environmental temperature changes, helping to maintain the homeostasis of body temperature
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Give 3 areas in the body where water is needed for lubrication:
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1. Chest (pleural and pericardial cavities) and Abdomen (peritoneal cavity) - where internal organs rub against one another.
2. Joints - where bones, ligaments, and tendons rub against one another. 3. Gastrointestinal tract - where mucus and other watery secretions moisten foods, which aids their smooth passage through the digestive system. "CAJG" |
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Define: mixture
Example? |
= a combination of elements or compounds that are physically blended together but not bound by chemical bonds.
Ex. air is a mixture of gases that includes nitrogen, oxygen, argon, and carbon dioxide. |
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Define: solution
Why does a solution look clear and transparent? |
= a liquid mixture in which solutes remain evenly dispersed among the solvent molecules.
- because the solute particles in a solution are very small. |
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Define: acid
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= a substance that dissociates into one or more hydrogen ions (H+) and one or more anions.
Because H+ is a single proton with one positive charge and is easily available to other molecules, an acid is also referred to as a proton donor. |
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Define: base
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= a substance that dissociates into one or more hydroxide ions (OH-) and one or more cations.
A base removes H+ from a solution and is therefore a proton acceptor. |
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Define: salt
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= a substance that when dissolved in water, dissociates into cations and anions, neither of which is H+ or OH-
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Give 2 examples of how salts are beneficial to the body:
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- salts (ex. KCl) are electrolytes that are important for carrying electrical currents (ions flowing from one place to another), especially in nerve and muscular tissues.
- ions of salts also provide many essential chemical elements in intracellular and extracellular fluids such as blood, lymph, and the interstitial fluid of tissues. |
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Why must intracellular and extracellular fluids contain almost balanced quantities of acids and bases?
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- to ensure homeostasis.
- The more hydrogen ions (H+) dissolved in a solution, the more acidic the solution; the more hydroxide ions (OH-) - The more basic (alkaline) the solution. |
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Define: pH scale
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= the scale that expresses the acidity or alkalinity of a solution.
(Acid 0 to 14 Alkaline) (7 is neutral) Unit: [H+] / litre |
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Practise. What is the pH of these concentrations? Are they acidic, basic or neutral?
1) 0.0000001 = 1x10^-7 2) 0.0001 = 1x 10^-4 3) 0.000000001 = 1x10^-9 |
1) pH = 7 neutral
2) pH = 4 acidic 3) pH = 9 basic |
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Define: buffer system
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= a system that converts strong acids or bases into weak acids or bases to ensure that the pH of fluids inside and outside cells remains almost constant.
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What are buffers and how do they work?
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= chemical compounds that convert strong acids and bases to weak acid and bases.
- They do this by removing or adding protons (H+). |
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Why is it important to have buffers that will convert strong acids or bases to weak ones?
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Strong acids (or bases) ionize easily and contribute many H+ (or OH-) to a solution. Therefore, they can change pH drastically, which can disrupt the body's metabolism.
Weak acids (or bases) do not ionize as much and contribute fewer H+ (or OH-). Hence, they have less effect on the pH |
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Define: carbonic acid–bicarbonate buffer system
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= an important buffer system in the body
Carbonic acid (H2CO3) can act as a weak acid, and the bicarbonate ion (HCO3-) can act as a weak base. Hence, this buffer system can compensate for either an excess or a shortage of H+. Ex. if there is an excess of H+ (an acidic condition), HCO3- can function as a weak base and remove the excess H+, as follows: H+ + HCO3- (bicarbonate) ---> H2CO3 (carbonic acid) Ex. If there is a shortage of H+ (an alkaline condition), by contrast, H2CO3 can function as a weak acid and provide needed H+ as follows: H2CO3 ---> H+ + HCO3- *Refer to end of Section 2.4 for clarification* |
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How do inorganic compounds differ from organic compounds?
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Inorganic compounds:
- usually lack carbon - structurally simple - ionic or covalent bonds Organic compounds: - always contain carbon - usually contain hydrogen - always have covalent bonds - structurally more complex |
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What functions does water perform in the body?
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- lubrication
- acts as a reactant or product for chemical reactions (hydrolysis and dehydration synthesis) - solvent - temperature moderation "LAST" |
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How do bicarbonate ions prevent buildup of excess H+?
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Biocarbonate ions (HCO3-) can function as a weak base and remove H+ ions by attaching to them.
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What are 5 important categories of organic compounds?
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Carbohydrates
Lipids Adenosine triphosphate (ATP) Proteins Nucleic acids "CLAPN" |
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Define: Carbohydrates
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= a large, diverse group of organic compounds with several functions.
- includes: sugars, glycogen, starches, and cellulose. |
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What 2 functions do carbohydrates have in animals and humans?
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- mainly a source of chemical energy for generating ATP needed to drive metabolic reactions.
- a few are used for building structural units. Ex. deoxyribose (a sugar that builds DNA) |
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What is the structure of carbohydrates?
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- Made up of carbon, Hydrogen, and oxygen.
- ratio of H:O is 2:1 - carbohydrates generally contain one water molecule for each carbon atom |
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What are the 3 groups of carbohydrates?
*they're grouped based on size |
Monosaccharides
Disaccharides Polysaccharides |
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Define: monosaccharides
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= simple sugars that contain from 3 to 7 carbons
- designated by names ending in “-ose” with a prefix that indicates the number of carbon atoms. Ex. monosaccharides with three carbons are called trioses (tri- = three). - tetroses (four-carbon sugars) - pentoses (five-carbon sugars) - hexoses (six-carbon sugars) - heptoses (seven-carbon sugars) |
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Define: monosaccharides
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= simple sugars that contain from 3 to 7 carbon atoms.
- designated by names ending in “-ose” with a prefix that indicates the number of carbon atoms. Ex. monosaccharides with three carbons are called trioses (tri- = three) - tetroses (four-carbon sugars) - pentoses (five-carbon sugars) - hexoses (six-carbon sugars) - heptoses (seven-carbon sugars) |
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Define: disaccharides
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= Simple sugars formed from the combination of two monosaccharides by dehydration synthesis.
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Examples of disaccharides
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Lactose (milk sugar) = glucose+galactose.
Maltose = glucose+glucose Sucrose = glucose + fructose |
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Define: Polysaccharides
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= a molecule made from tens to hundreds of monosaccharides joined by dehydration synthesis.
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Examples of polysaccharides
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Glycogen (the stored form of carbohydrates in animals).
Starch (the stored form of carbohydrate in plants and main carbohydrate in food). Cellulose (part of cell walls in plants that cannot be digested by humans but aids movement of food through intestines). |
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Monosaccharides & disaccharides are known as?
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Simple sugars.
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Disaccharides can be broken down into smaller parts (monosccharides) by what type of chemical reaction?
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Hydrolysis
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Which monosaccharide is broken down by cells to produce ATP?
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= glucose (a hexose)
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How are polysaccharides different from the simple sugars?
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- usually insoluble in water
- do not taste sweet |
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What is glycogen?
What is it made up of? |
- it is the main polysaccharide and is the stored form of carbohydrate in the human body.
- made entirely of glucose monomers linked to one another in branching chains Fig 2-16 |
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What body cells store glycogen?
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Liver & skeletal muscle cells.
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Define: Lipids
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= one of the categories of organic compounds
* the others are carbohydrates, proteins & nucleic acids. |
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Lipids make up how much % in the body mass of a lean adult?
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18 - 25 %
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How are lipids and carbohydrates similar?
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- made up of carbon, hydrogen and oxygen
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Why do lipids and carbohydrates react differently to water?
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Lipids are hydrophobic - lipids have fewer oxygen atoms, so there are fewer polar covalent bonds. As a result, lipids are insoluble in polar solvents such as water.
Carbohydrates are hydrophilic - they have a 2:1 ratio of H to O, so have more polar covalent bonds, which can react well with the polarity of water molecules. |
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Despite lipids being hydrophobic, which type of lipids are soluble in blood plasma?
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- only fatty acids (the smallest type of lipids) can dissolve in watery blood plasma.
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How do lipid molecules become more soluble in blood plasma?
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- they join with hydrophilic protein molecules to make lipid/protein complexes called lipoproteins.
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Define: lipoprotein
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= lipid/protein complexes formed by lipid molecules joining with hydrophilic protein molecules to allow lipid molecules to become more soluble in blood plasma.
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What is the structure of a lipoprotein that makes it soluble?
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- proteins are on the outside and the lipids are on the inside
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3 functions of lipoproteins
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- Transport lipids in the blood
- carry triglycerides and cholesterol to tissues - remove excess cholesterol from the blood. |
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Fatty acids
What are they? Structure? Function? |
= one of the simplest lipids
- a carboxyl group and a hydrocarbon chain (Fig 2-17a) - Used to synthesize triglycerides and phospholipids - catabolized to generate adenosine triphosphate (ATP) |
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Triglycerides or Triacyglycerol (fats & oils)
What are they? Structure? Function? |
= the most abundant lipids in our bodies and diet.
- three-carbon glycerol molecule forms the backbone of a triglyceride (Figure 2-17b, c). Three fatty acids are attached by dehydration synthesis reactions, one to each carbon of the glycerol backbone. The chemical bond formed where each water molecule is removed is an ester linkage (see Table 2-5). Protection Insulation Energy storage |
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Phospholipids
What are they? Structure? Function? |
= a type of lipid
Like triglycerides, phospholipids have a glycerol backbone and two fatty acid chains attached to the first two carbons. In the third position, however, a phosphate group (PO43-) links a small charged group that usually contains nitrogen (N) to the backbone (Figure 2-18). This portion of the molecule (the “head”) is polar and can form hydrogen bonds with water molecules. The two fatty acids (the “tails”), by contrast, are nonpolar and can interact only with other lipids. Molecules that have both polar and nonpolar parts are said to be amphipathic (am-fē-PATH-ic; amphi- = on both sides; -pathic = feeling). Amphi-pathic phospholipids line up tail-to-tail in a double row to make up much of the membrane that surrounds each cell (Figure 2-18c). Make up cell membranes. |
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Steroids
What are they? Structure? |
= a type of lipid
- have four rings of carbon atoms (colored gold in Figure 2-19). Body cells synthesize other steroids from cholesterol (Figure 2-19a), which has a large nonpolar region consisting of the four rings and a hydrocarbon tail. |
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Eicosanoids
What are they? Structure? Functions of prostaglandins? Function of leukotrienes? *2 subclasses of eicosanoids: prostaglandins and leukotrienes |
(ī-KŌ-sa-noids; eicosan- = twenty)
= lipids derived from a 20-carbon fatty acid. - Prostaglandins modify responses to hormones, blood clotting, inflammation, immunity, stomach acid secretion, airway diameter, lipid breakdown, and smooth muscle contraction. - Leukotrienes participate in allergic and inflammatory responses. |
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Define: Proteins
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= large molecules that contain carbon, hydrogen, oxygen, and nitrogen
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Functions of Proteins
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"STRICC"
Structural Form structural framework of various parts of the body. Ex: collagen in bone and other connective tissues, and keratin in skin, hair, and fingernails. Transport Carry vital substances throughout body. Ex: hemoglobin, which transports most oxygen and some carbon dioxide in the blood. Regulatory Function as hormones that regulate various physiological processes; control growth and development; as neurotransmitters, mediate responses of the nervous system. Ex: the hormone insulin, which regulates blood glucose level, and a neurotransmitter known as substance P, which mediates sensation of painin the nervous system. Immunological Aid responses that protect body against foreign substances and invading pathogens. Ex: antibodies and interleukins. Contractile Allow shortening of muscle cells, which produces movement. Ex: myosin and actin. Catalytic Act as enzymes that regulate biochemical reactions. Ex: salivary amylase, sucrase, and ATPase. *Table 2.8 |
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Define: amino acids
Structure? |
= monomers of proteins
Each of the 20 different amino acids has a hydrogen (H) atom and three important functional groups attached to a central carbon atom (Figure 2-20a): (1) an amino group (—NH2), (2) an acidic carboxyl group (—COOH), and (3) a side chain (R group). Fig 2-20 |
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In an amino acid, what is the minimum number of carbon atoms? Of nitrogen atoms?
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An amino acid has a minimum of two carbon atoms and one nitrogen atom.
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Define: peptide bond
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= the covalent bond joining each pair of amino acids
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Where is a peptide bond formed?
How is a peptide bond formed? |
It always forms between the carbon of the carboxyl group (—COOH) of one amino acid and the nitrogen of the amino group (—NH2) of another.
As the peptide bond is formed, a molecule of water is removed (Figure 2-21), making this a dehydration synthesis reaction. |
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What is a:
Dipeptide? Tripeptide? Peptide? Polypeptide? |
= 2 amino acids combined
= 3 amino acids combined = 4 - 9 = 10 - 2000 or more Small proteins may consist of a single polypeptide chain with as few as 50 amino acids. Larger proteins have hundreds or thousands of amino acids and may consist of two or more polypeptide chains folded together. |
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Define: Primary structure
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= the unique sequence of amino acids that are linked by covalent peptide bonds to form a polypeptide chain (Figure 2-22a on page 52).
*A protein's primary structure is genetically determined, and any changes in a protein's amino acid sequence can have serious consequences for body cells. |
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Define: Secondary structure
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= the repeated twisting or folding of neighboring amino acids in the polypeptide chain (Figure 2-22b). Two common secondary structures are alpha helixes (clockwise spirals) and beta pleated sheets. The secondary structure of a protein is stabilized by hydrogen bonds, which form at regular intervals along the polypeptide backbone.
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Define: Tertiary structure
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= refers to the three-dimensional shape of a polypeptide chain.
Each protein has a unique tertiary structure that determines how it will function. The tertiary folding pattern may allow amino acids at opposite ends of the chain to be close neighbors (Figure 2-22c). Several types of bonds can contribute to a protein's tertiary structure. |
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Define: Quaternary structure
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= the arrangement of the individual polypeptide chains relative to one another in those proteins that contain more than one polypeptide chain (not all of them do)
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The variation in proteins' structure and shape is directly related to what?
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The variation in structure and shape is directly related to their diverse functions
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Define: denaturation
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= the process in which a protein encounters an altered environment, it may unravel and lose its characteristic shape (secondary, tertiary, and quaternary structure)
*denatured proteins are no longer functional. |
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Define: Enzymes
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= protein molecules that catalyze chemical reactions in living cells.
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3 important properties of enzymes:
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1. Enzymes are highly specific. Each particular enzyme binds only to specific substrates—the reactant molecules on which the enzyme acts. Of the more than 1000 known enzymes in your body, each has a characteristic three-dimensional shape with a specific surface configuration, which allows it to recognize and bind to certain substrates. In some cases, the part of the enzyme that catalyzes the reaction, called the active site, is thought to fit the substrate like a key fits in a lock. In other cases the active site changes its shape to fit snugly around the substrate once the substrate enters the active site. This change in shape is known as an induced fit.
Not only is an enzyme matched to a particular substrate, it also catalyzes a specific reaction. From among the large number of diverse molecules in a cell, an enzyme must recognize the correct substrate and then take it apart or merge it with another substrate to form one or more specific products. 2. Enzymes are very efficient. Under optimal condition |
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There are 2 varieties of nucleic acids.
1. What does DNA do? 2. What does RNA do? |
- forms the inherited genetic material inside each human cell.
- relays instructions from the genes to guide each cell's synthesis of proteins from amino acids |
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What are nucleotides?
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= monomers that make up nucleic acids.
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Each nucleotide of DNA consists of what 3 parts?
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1. Nitrogenous base = DNA contains four different nitrogenous bases, which contain atoms of C, H, O, and N. In DNA the four nitrogenous bases are adenine (A), thymine (T), cytosine (C), and guanine (G).
2. Pentose sugar = a five-carbon sugar called deoxyribose attaches to each base in DNA. 3. Phosphate group. Phosphate groups (PO43-) alternate with pentose sugars to form the “backbone” of a DNA strand; the bases project inward from the backbone chain (Figure 2-24b). |
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What is a double helix?
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= a model of DNA in which DNA resembles a spiral ladder (Figure 2-24b). Two strands of alternating phosphate groups and deoxyribose sugars form the uprights of the ladder. Paired bases, held together by hydrogen bonds, form the rungs.
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What is RNA?
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= the sugar in the RNA nucleotide
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Differences between DNA and RNA:
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1. DNA: deoxyribose sugar
RNA: ribose sugar 2. double stranded single stranded 3. Pyrmidine base is thymine Pyrmidine base is uracil |
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What is ATP?
How does it work? Structure? |
= the energy in living systems
- it transfers the energy liberated in exergonic catabolic reactions to power cellular activities that require energy (endergonic reactions). - consists of three phosphate groups attached to adenosine, a unit composed of adenine and the five-carbon sugar ribose. |
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What are some cellular activities that depend on energy supplied by ATP?
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Cellular activities that depend on energy supplied by ATP include muscular contractions, movement of chromosomes, transport of substances across cell membranes, and synthesis (anabolic) reactions.
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What is ADP?
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= a molecule produced by removal of the 3rd phosphate group (PO43-) in ATP through hydrolysis (the addition of water) and ATPase (an enzyme that catalyzes the hydrolysis of ATP)
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What is cellular respiration?
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= a process that supplies the energy needed to attach a phosphate group to ADP (by the catabolism of glucose)
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