Exam #2 (2 & 6) Flashcards

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1
Q

Element

A

A substance that consists of only one kind of atom and cannot be separated into simpler parts by chemical methods; 92 are naturally occuring;

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2
Q

4 Most Common Elements in Organisms

A
  • Carbon
  • Hydrogen
  • Oxygen
  • Nitrogen
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3
Q

Atoms

A

The basic units of all matter

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4
Q

Subatomic Particles Composing Atoms

A
  • Neutrons: uncharged, found in the nucleus
  • Protons: positively charged, found in the nucleus
  • Electrons: negatively charged, form cloud around the nucleus
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5
Q

Atomic Number

A

The number of protons in the nucleus

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6
Q

Atomic Weight (Mass)

A

The sum of the number of protons and neutrons found in an atom

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7
Q

Isotope

A

Forms of the same chemical element that differ in their number of neutrons; useful tools in biological research

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8
Q

Molecule

A

Two or more atoms held together by chemical bonds

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9
Q

Chemical Bond

A

Form when atoms lose, gain, or share the electrons in their outer shell to achieve the most stable state

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10
Q

Ionic Bond

A

A strong chemical bond resulting from the attraction of positively and negatively charged ions; resulting product is called a salt

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11
Q

Covalent Bond

A

Strong chemical bond formed by the sharing of electrons between atoms; share pairs of valence electrons

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12
Q

Hydrogen Bond

A

Weak attraction between a positively charged hydrogen atom of one compound and a negatively charged atom of another compound; charges of the two atoms are due to polar covalent bonds

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13
Q

Ion

A

An atom that gains or loses an electron; becomes positively or negatively charged

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14
Q

Cation

A

Positively charged ion

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15
Q

Anion

A

Negatively charged ion

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16
Q

pH

A

Scale of 0 to 14 that expresses the acidity or alkalinity of a solution

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17
Q

Buffer

A

Substances in a solution that acts to prevent changes in pH

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18
Q

Macromolecules

A

Large molecules that contain 10s of atoms to billions of atoms; complex enough that life is usually necessary to make them
- organic: the molecules contain at least Carbon and Hydrogen

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19
Q

4 Types of Macromolecules

A
  • Carbohydrates: sugars, starch, glycogen, chitin, celluose, peptidoglycan (most composed of ringed molecules)
  • Lipids: triglycerides, phospholipids, steroids
  • Proteins: building blocks, enzymes
  • Nucleic Acids: DNA, RNA
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20
Q

Monosaccharides

A

Simple sugars; primary choice to make cellular energy (ATP)

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21
Q

Polysaccharides

A

Carbohydrates that cells make to store energy in the form of a carbohydrate; glycogen in animals, cellulose in plants; chitin, cellulose, and peptidoglycan are complex carbohydrate molecules that cells use as building blocks of cell walls

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22
Q

Triglycerides

A

Fat molecules that cells construct to store energy

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23
Q

Saturated Fat

A

Fatty acid that contains no double bonds

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24
Q

Unsaturated Fat

A

Fatty acid with one or more double bonds

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25
Q

Phospholipids

A

Fat molecules that cells construct as building blocks for cell membranes and other membrane-bound organelles

26
Q

Steroids

A

Fat molecules that have four carbon rings connected to each other; cholesterol and some hormones

27
Q

Proteins

A

Made up of smaller amino acid molecules (20 different types); most made up of about 200 adjacent amino acids; conduct most of the cellular work and are used as building blocks for cell walls, cell membranes, flagella, cilia, and organelles; also used as enzymes that allow cells to create chemical reactions

28
Q

Nucleotides

A

Small molecules that make up nucleic acids

29
Q

Enzymes

A

Proteins that function as biological catalysts, facilitating the conversion of a substrate into a product; work on only one type of substrate; end is -ase

30
Q

Catalyst

A

Substance that speeds up the rate of a chemical reaction without being altered or depleted in the process

31
Q

Active Site

A

Small crevices on enzymes that allow a substrate to precisely bind to it

32
Q

Enzyme-Substrate Complex

A

The temporary binding of an enzyme and a substrate during which the activation energy is lowered for the reaction

33
Q

Cofactors and Coenzymes

A

Inorganic (minerals) and organic (vitamins); loosely attach to enzymes and complete the active site; without them, enzymes cannot function correctly and normal metabolism is impaired

34
Q

Environmental Factors That May Disrupt the Normal Shape and Function of Enzymes

A
  • Temperature: speed up or slow down rate of reactions; denaturation at too high temps
  • Salt Concentration: most operate best at low concentrations
  • pH: best at values slightly above 7
35
Q

Allosteric Regulation

A

The temporary binding of regulatory molecules to the allosteric site of an enzyme; can make enzymes more or less reactive (starting or stopping a chemical reaction)

36
Q

Competitive Inhibition

A

An inhibitor molecule binds to the active site of an enzyme and prevents the true substrate from binding

37
Q

Non-Competitive Inhibition

A

An inhibitor molecule binds to the allosteric site of an enzyme and permanently changes the shape of the enzyme

38
Q

Metabolism

A

The sum of all chemical reactions that occur within a cell

39
Q

Anabolic Chemical Reactions

A

Chemical reactions in which smaller molecules are joined together to build larger molecules; typically require an input of energy; dehydration synthesis

40
Q

Catabolic Chemical Reactions

A

Chemical reactions in which larger molecules are broken apart into smaller ones; typically release energy; hydrolysis; release the energy stored within covalent bonds of macromolecules and produce ATP

41
Q

ATP (Adenosine Triphosphate)

A

A modified RNA nucleotide with three phosphate groups; the covalent bond attaching the last phosphate group is considered a high energy bond that a cell uses for energy

42
Q

REDOX (reduction-oxidation) Reactions

A

Transfer of electrons (and H+) from one molecule to another; one becomes reduced (gains) and one becomes oxidized (loses); always occur together

43
Q

NAD+ and FAD+

A

Molecules that act as electron acceptors in catabolic chemical reactions; one is reduced to NADH, the other is reduced to FADH2

44
Q

Glycolysis: Simplified Reaction

A

Glucose (6 carbons) + 2 ATP + 2 NAD+ + 10 enzyme mediated chemical reactions —-> 2 pyruvate (3 carbons) + 4 ATP + 2 NADH

45
Q

Steps of Glycolysis

A
  • First step in the degradation of sugars
  • One glucose enters the pathway
  • Two pyruvate are produced at the end of the 10 step process
  • Four ATP are produced, two used to initiate reactions (2 ATP generated net)
  • Two pairs of electrons passed to both NAD+, reducing both of them to NADH
  • No free oxygen is consumed
46
Q

Krebs Cycle: Simplified Reactioin

A

Pyruvate + 4 NAD+ + 1 FAD+ —-> 3 CO2 + 4 NADH + 1 FADH2 + 1 ATP

47
Q

Summary of Krebs Cycle

A
  • For each glucose molecule, 2 pyruvate enter the pathway
  • The 3-carbon pyruvate molecule is broken down one carbon at a time over a series of 9 reactions, producing CO2 as a product
  • Everything except the first step is cyclic: pyruvic acid + NAD+ —-> Acetyl CoA (2C) + CO2 + NADH
  • Acetyl CoA will then combine with a 4-carbon oxaloacetic acid molecule forming a 6-carbon citric acid molecule; two additional carbons removed one at a time
  • The energy released from the reactions are lost as heat and stored in the electron carriers using redox reactions
  • Produces 1 ATP, 4 NADH, 1 FADH2
48
Q

Electron Transport Chain

A

NADH and FADH2 are oxidized into NAD+ and FAD+; the electrons are transferred to a series of five to seven electron acceptors (proteins) found within a membrane; these electrons have energy that will construct ATP molecules for the cell

49
Q

ATP Synthase

A

An enzyme used to make ATP; found in the cell membranes of prokaryotic organisms and in the inner mitochondrial membrane of eukaryotic organisms

50
Q

Terminal Electron Acceptor (TEA)

A

The last molecule to accept the electrons found in the NADH and FADH2 molecules; oxygen in aerobic respiration and oxygen containing salts in anaerobic respiration

51
Q

Aerobic Respiration

A

Krebs + ETC using oxygen; oxygen is reduced to water

52
Q

Anaerobic Respiration

A

Krebs + ETC using inorganic molecules

53
Q

Fermentation

A

Pyruvate is further oxidized without free oxygen; unless glycolysis is included in the calculations, these additional pathways do not produce usable energy (ATP); main purpose is to convert NADH into NAD+ to be used in glycolysis

54
Q

Two Main Types of Fermentation

A
  • Alcohol (yeast, some bacteria)

- Acidic (humans, some bacteria

55
Q

Propionibacterium

A

Conduct acidic fermentation that gives Swiss cheese its characteristic flavor; the holes represent the CO2 escaping the cheese

56
Q

Mixed Acid Fermentation

A

Type of Fermentation in which some bacteria produce a mixture of acetic, lactic, succinic, and formic acids (super fermenters: lower the pH of medium below 4.0)

57
Q

Drawbacks to Fermentation

A
  • Wastes large amounts of energy found in glucose; only net of 2 ATP produced from a single glucose molecule; chemical reactions are only 2% efficient
  • The waste products produced can impede or stop cell function
58
Q

Other Carbohydrates (besides glucose) Used to Produce ATP

A
  • Other sugars (fructose, sucrose, lactose, etc.) will first meed to be converted into glucose and then proceed into glycolysis
  • Polysaccharides are broken down into multiple glucose (1000+) and then each is placed into glycolysis
59
Q

Triglycerides Used to Produce ATP

A
  • Must first be broken down to its component molecules: 3 fatty acids and a glycerol molecule
  • Fatty acids are converted into numerous Acetyl CoA by beta-oxidation
  • Acetyl CoA are inserted into the Krebs Cycle, bypassing the transition step
  • Glycerol is converted into pyruvate which is inserted into the Krebs cycle
  • Approximately 458 ATP can be generated from a single one of these molecules
60
Q

Proteins Used to Produce ATP

A
  • Can be used if the cell does not have enough carbohydrates or triglycerides available to use as energy for ATP production
  • First, broken down into individual amino acids
  • NH2 must be removed from each amino acid (deamination) and converted to urea
  • The remaining portions of the amino acids are converted into one of the substrates of the Krebs Cycle
  • Each amino acid is reduced into NADH and FADH2 in the Krebs Cycle and used later to generate ATP in the ETC (12-16 ATP are generated per amino acid)