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biology med 103 > topic 8 > Flashcards

topic 8 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

anabolic processes are where energy is

A

stored

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2
Q

catabolic processes are where energy is

A

released

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3
Q

catabolic pathways ____

A

breakdown complex molecules into simpler compounds

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4
Q

anabolic pathways ____

A

synthesize complicated molecules from simpler ones

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5
Q

photosynthesis is an example of (catabolic or anabolic)?

A

anabolic pathway

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6
Q

cellular respiration is an example of?

A

catabolic pathway

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7
Q

the first law of thermodynamics states that ____

A

energy cannot be created or destroyed (but can be transferred/transformed)

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8
Q

the second law of thermodynamics states that ____

A

spontaneous changes that do not require outside energy (no energy consumption) increase the entropy (disorder)
of the universe

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9
Q

what is free energy? (ΔG)

A

a living system’s energy that can do work under cellular conditions

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10
Q

what are exergonic reactions?

A
  • when ΔG < 0
  • free energy is released
  • spontaneous reactions
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11
Q

what are endergonic reactions?

A
  • ΔG > 0
  • absorb free energy from their surroundings
  • non-spontaneous reactions
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12
Q

what is ATP?

A
  • adenosine triphosphate
  • nucleotide that stores energy in phosphate bonds
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13
Q

what is the function of ATP?

A

provides energy for cellular functions

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14
Q

ATP powers cellular work by energy coupling; what is energy coupling?

A

the use of an exergonic process to drive an
endergonic one

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15
Q

what are the 3 main types of endergonic cellular work?

A
  • mechanical
  • transport
  • chemical
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16
Q

how is ATP an example of mediated energy coupling?

A

ATP hydrolysis provides the energy required for the endergonic reaction to occur

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17
Q

what is phosphorylation?

A

the transfer of a phosphate to other molecules

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18
Q

how does ATP undergo mechanical, transport, and chemical work?

A

mechanical - ATP phosphorylates motor proteins

transport - ATP phosphorylates transport proteins

chemical - ATP phosphorylates key reactants

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19
Q

what is the activation energy Ea?

A

the initial amount of energy need to start a chemical reaction

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20
Q

what does the activation energy do?

A

it is needed to de-stabilize the structure of the reactants so they can react more easily

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21
Q

what is denaturation?

A

the loss of a protein’s native conformation due to unravelling => loss of function

22
Q

what are some environmental factors that may affect enzyme activity?

A
  • pH
  • temperature
  • cofactors
23
Q

what are cofactors?

A

non-protein enzyme helpers required for enzyme activity

24
Q

what is an example of an inorganic cofactor?

A

metal ions (ex: Zn, Cu)

25
Q

what are coenzymes? give an example

A

organic cofactors such as vitamins

26
Q

what are irreversible inhibitors?

A

bind to an enzyme by covalent bonding => inhibition is irreversible

27
Q

examples of irreversible inhibitors of the nervous sytsem?

A

sarin, DDT, parathion

28
Q

what are penicillin derivatives?

A

inhibit the enzyme transpeptidase that synthesizes the bacterial cell wall peptidoglycan

29
Q

what are reversible inhibitors?

A

bind to enzymes by weak bonds (non-covalent interactions: H-bonds, hydrophobic interactions, ionic bonds) => inhibition is reversible

30
Q

what are the 2 types of reversible inhibitors?

A
  • competitive inhibitors
  • non-competitive inhibitors
31
Q

what are competitive inhibitors?

A

-compete with the substrate
- bind to the active site of an enzyme (weak binding) to inhibit substrate binding

32
Q

what are non-competitive inhibitors?

A
  • bind to another part of an
    enzyme not to the active site
  • change the shape of the enzyme
  • inhibit the function of the enzyme
33
Q

in ONLY competitive inhibition, how can inhibition be overcome?

A

by adding excess substrate

34
Q

what are 2 basic methods of enzyme regulation?

A
  1. regulation of gene expression
  2. feedback inhibition (by allosteric regulation)
35
Q

what is feedback inhibition?

A
  • prevents a cell from wasting chemical resources by synthesizing more product than is needed
  • (end products always inhibits the pathway)
36
Q

give 2 examples of feedback inhibition

A
  1. inhibition of catabolic pathways by ATP
  2. inhibition of anabolic pathways by their end product (tryptophan)
37
Q

what is allosteric regulation?

A
  • a form of reversible modulation common in enzymes (and proteins) made from polypeptide subunits
    – can be positive (activation) or negative (inhibition)
38
Q

allosteric activators stabilize the ____

A

active form of the enzyme

39
Q

allosteric inhibitors stabilize the ____

A

inactive form of the enzyme

40
Q

what is homotropic allosteric regulation?

A

binding of substrate to active site of one subunit locks all subunits into active conformation

41
Q

what is heterotropic allosteric regulation?

A

binding of regulatory molecules to sites other than the active sites

42
Q

what is cooperativity?

A

special form of positive allosteric regulation
(activation) that can amplify enzyme activity

43
Q

given an example of cooperativity

A
  • O2 binding to hemoglobin
  • the binding of substrate (oxygen) at one subunit increases the binding affinity of the other subunits (oxygen= allosteric activator)
44
Q

allosteric inhibitors can be ____

A

competitive or non-competitive

45
Q

heterotropic allosteric modulator

A

non-competitive inhibitors + activators

46
Q

give an example of a heterotropic allosteric activator

A

AMP is a heterotropic allosteric activator of PFK

=> (phosphofructokinase= glycolysis enzyme)

47
Q

give an example of a heterotropic allosteric inhibitor

A

CO2 is a heterotropic allosteric inhibitor (noncompetitive inhibitor) of hemoglobin

=> reduces hemoglobin’s affinity for oxygen
=> oxygen is released in the tissues

48
Q

homotropic allosteric modulator

A

(competitive inhibitors + activators)

49
Q

give an example of a homotropic allosteric modulator

A

O2 and CO are homotropic allosteric
modulators of hemoglobin

50
Q

O2 is a _____ of hemoglobin

A

homotropic allosteric activator

51
Q

CO is a _____ of hemoglobin

A

competitive inhibitor

52
Q

what is the main difference between homotropic and heterotropic allosteric modulators?

A

heterotropic –> a regulatory molecule that is NOT the enzyme’s substrate

homotropic –> both a substrate for its target enzyme and a regulatory molecule of the enzyme’s activity

biology med 103 (13 decks)

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