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Microbiology > Lecture 7 > Flashcards

Lecture 7 Flashcards

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Biology 101 flashcards
1
Q

What is metabolism?

A

pertains to all chemical reactions and physical workings of the cell

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2
Q

What is anabolism?

A
  • any process that results in synthesis of cell molecules and structures
  • a building and bond-making process that forms larger macromolecules from smaller ones
  • requires the input of energy
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3
Q

What is catabolism?

A
  • breaks the bonds of larger molecules into smaller molecules
  • releases energy
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4
Q

What are the functions of metabolism?

A
  • assembles smaller molecules into larger macromolecules as needed for the cell; ATP (energy) is utilized to form bonds (anabolism)
  • degrades macromolecules into smaller molecules, a process which yields energy (catabolism)
  • stores energy in the form of ATP (adenosine triphosphate)
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5
Q

do chemical reactions need enzymes?

A

yes

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6
Q

What are enzymes?

A

are catalysts that increase the rate of chemical reactions without becoming part of the products or being consumed in the reaction

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7
Q

How do enzymes work?

A

Reactants are converted into products by bond formation or bond breakage

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8
Q

What is a substrate?

A

reactant molecules acted on by an enzyme

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9
Q

What do enzymes do to a reaction?

A

Speed up the rate of reactions without increasing the temperature

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10
Q

Are enzymes or substrates larger?

A

enzymes

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11
Q

What is the active site?

A

Where substrate binds and reacts

lock and key only 1 will work

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12
Q

Process of enzyme

A

Binds substrate

Participates directly in changes to substrate

Does not become part of the products

Not used up by the reaction

Can be used over and over again

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13
Q

Can enzymes be reused?

A

Yes

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14
Q

How fast are enzymes?

A

the number of substrate molecules converted per enzyme per second

catalase: several million

lactate dehydrogenase: a thousand

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15
Q

What do simple enzymes consist of?

A

just a protein?

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16
Q

What do conjugated enzymes conatin?

A

protein and nonprotein molecules

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17
Q

What is an apoenzyme?

A

protein portion of a conjugated enzyme

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18
Q

What is a cofactor?

A

either organic molecules called coenzymes or inorganic elements (metal ions

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19
Q

What must happen with an enzyme- substrate interaction?

A

A temporary enzyme-substrate union must occur at the active site

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20
Q

What is the bond between substrate and enzyme like?

A

Bond formed between the substrate and enzyme are weak and easily reversible

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21
Q

What happens once the enzyme-substrate complex has formed?

A

an appropriate reaction occurs on the substrate, often with the aid of a cofactor

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22
Q

What is the need of microorganisms for reactions?

A

The need of microorganisms for trace elements arises from their roles as cofactors for enzymes

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23
Q

What some examples of cofactors?

A

iron, copper, magnesium, manganese, zinc, cobalt, selenium, etc.

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24
Q

What is the role of cofactors?

A
  • help bring the active site and substrate close together

- participate directly in chemical reactions with the enzyme-substrate complex

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25
Q

What are coenzymes?

A

organic compounds that work in conjunction with an apoenzyme

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26
Q

What is the general function of a coenzyme?

A

general function is to remove a chemical group from one substrate molecule and add it to another substrate molecule
-carry and transfer hydrogen atoms, electrons, carbon dioxide, and amino groups

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27
Q

What are coenzymes derived from?

A

vitamins

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28
Q

How are enzymes classified?

A

Enzymes are classified and named according to characteristics such as site of action, type of action, and substrate

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29
Q

How is the name of an enzyme derieved?

A

prefix or stem word derived from a certain characteristic, usually the substrate acted upon or type of reaction catalyzed

ending –ase

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30
Q

What is a carbohydrase?

A

digests a carbohydrate substrate

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31
Q

What is amylase?

A

acts on starch

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32
Q

What is maltase?

A

digests maltose

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33
Q

What are proteinase, protease, and peptidase?

A

hydrolyzes the peptide bonds of a protein

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34
Q

What is lipase?

A

digests fats

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35
Q

What is deoxyribnuclease?

A

digests DNA

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36
Q

What is syntetase or polymerase?

A

bonds many small molecules together

37
Q

What are constitutive enzymes?

A

always present in relatively constant amounts regardless of the amount of substrate

38
Q

What are regulated enzymes?

A

production is turned on (induced) or turned off (repressed) in responses to changes in concentration of the substrate

39
Q

How are enzymes regulated?

A

Activity of enzymes influenced by the cell’s environment

40
Q

What are normal conditions for enzymes?

A

natural temperature, pH, osmotic pressure

changes in the normal conditions causes enzymes to be unstable or labile

41
Q

How can enzymes be denatured?

A

weak bonds that maintain the native shape of the apoenzyme are broken

this causes disruption of the enzyme’s shape

prevents the substrate from attaching to the active site

42
Q

How do metabolic pathways normally occur?

A

Often occur in a multistep series or pathway, with each step catalyzed by an enzyme

43
Q

What happens with the product of a reaction?

A

Product of one reaction is often the reactant (substrate) for the next, forming a linear chain or reaction

44
Q

What do branches of pathways do?

A

Many pathways have braches that provide alternate methods for nutrient processing

45
Q

What is the cylic form of a pathway?

A

Others have a cyclic form, in which the starting molecule is regenerated to initiate another turn of the cycle

46
Q

Do metabolic pathways stand alone or together/

A

Do not stand alone; interconnected and merge at many sites

47
Q

What is competitive inhibition?

A

Molecule that mimcks substrate occupies the active site, preventing the actual substrate from binding

48
Q

What is noncompetitive inhibition?

A

enzymes have two binding sites: the active site and a regulatory site

molecules bind to the regulatory site

slows down enzymatic activity once a certain concentration of product is reached

49
Q

What is enzyme repression?

A

genetic apparatus responsible for replacing enzymes is repressed
(takes longer than feedback inhibition)

50
Q

What is enzyme induction?

A

enzymes appear (are induced) only when suitable substrates are present

51
Q

What happens when E. coli is inoculated into a medium containing only lactose?

A

it will produce the enzyme lactase to hydrolyze it into glucose and galactose

52
Q

What happens If E. coli is subsequently inoculated into a medium containing only sucrose?

A

it will cease to synthesizing lactase and begin synthesizing sucrase

53
Q

What does enzyme induction in e. coli allow the organism to do?

A

Allows the organism to utilize a variety of nutrients, and prevents it from wasting energy by making enzymes for which no substrates are present

54
Q

What is exergonic ?

A

reactions release energy, making it available for cellular work

55
Q

What is endergonic?

A

reactions are driven forward with the addition of energy

56
Q

What are exergonic and endergonic done together or separate?

A

Exergonic and endergonic reactions are often coupled so that released energy is immediately put to work

57
Q

What happens during exergonic reactions?

A

During exergonic reactions, energy released by bonds is stored in high-energy phosphate bonds such as ATP

58
Q

What fuels endergonic cell reactions?

A

ATP fuels endergonic cell reactions

59
Q

What is oxidation?

A

loss of electrons

when a compound loses electrons, it is oxidized

60
Q

What is reduction?

A

gain of electrons

when a compound gains electrons, it is reduced

61
Q

What are oxidation-redution reactions?

A

Oxidation-reduction (redox) reactions are common in the cell and are indispensable to the required energy transformations

62
Q

What are oxidoreductases?

A

enzymes that remove electrons from one substrate and add them to another

63
Q

What are the coenzymes in oxidoredutases?

A

their coenzyme carriers are nicotinamide adenine dinucleotide (NAD) and flavin adenine dinucleotide (FAD)

64
Q

What is a redox pair?

A

an electron donor and an electron acceptor involved in a redox reaction

65
Q

What can happen to energy present in the electron acceptor?

A

Energy present in the electron acceptor can be captured to phosphorylate (add an inorganic phosphate) to ADP or to some other compound to store energy in ATP

66
Q

What does metabolism do in catabolism?

A

Metabolism uses enzymes to catabolize organic molecules to precursor molecules that cells then use to anabolize larger, more complex molecules

67
Q

What is reducing power?

A

electrons available in NADH and FADH2

68
Q

Where is energy stored?

A

stored in the bonds of ATP

69
Q

What is aerobic respiration?

A

a series of reactions that converts glucose to CO2 and allows the cell to recover significant amounts of energy

70
Q

What is utilized in aerobic respiration?

A

utilizes glycolysis, the Krebs cycle, and the electron transport chain

71
Q

What does aerobic respiration rely on?

A

relies on free oxygen as the final electron and hydrogen acceptor

72
Q

Who performs aerobic respiration?

A

characteristic of many bacteria, fungi, protozoa, and animals

73
Q

What is anaerobic respiration?

A

used by strictly anaerobic organisms and those who are able to metabolize with or without oxygen

74
Q

What is involved with anaerobic respirtation?

A

involves glycolysis, the Krebs cycle, and the electron transport chain

75
Q

What are used as final electron acceptors in anaerobic respiration?

A

uses NO3-, SO42-, CO33-, and other oxidized compounds as final electron acceptors

76
Q

What is fermentation?

A

incomplete oxidation of glucose

77
Q

Is oxygen required in fermentation?

A

no

78
Q

What are the final electron acceptors in fermentation?

A

organic compounds

79
Q

Where does the kreb cyle take place?

A

The Krebs cycle takes place in the cytoplasm of bacteria and in the mitochondrial matrix of eukaryotes

80
Q

What is the electron transport chain?

A

A chain of special redox carriers that receives reduced carriers (NADH, FADH2) generated by glycolysis and the Krebs cycle

81
Q

Where does the electron transport chain occur in prokaryotes?

A

the cell membrane

82
Q

Where does the electron transport chain occur in eukaryotes?

A

inner mitochondrial membrane

83
Q

Where does released energy from electron carries go?

A

Released energy from electron carriers in the electron transport chain is channeled through ATP synthase

84
Q

What happens in the final step of the electron transport chain?

A

in the final step of the process, oxygen accepts electrons and hydrogen, forming water

85
Q

What is oxidative phosporylation?

A

the coupling of ATP synthesis to electron transport

86
Q

How many atps does Nadh give rise to in the electron chain?

A

3

87
Q

how many atps does fadh2 give rise to in the electron chain?

A

2

88
Q

what happens in the terminal step of aerobic respiration?

A

catalyzed by cytochrome aa3, also known as cytochrome oxidase

adapted to receive electrons from cytochrome c, pick up hydrogens from solution, and react with oxygen to form water

2H+ + 2e- + ½ O2  H20

Microbiology (12 decks)

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