Unit 3 Flashcards

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1
Q

What is the importance of the active site in an enzyme?

A

Enzymes catalyze a specific reaction with a specific substrate which fits perfectly into the active site

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2
Q

What would happen if the enzyme’s active site changed?

A

The substrate would no longer fit in the active site, wouldn’t be able to catalyze the reaction

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3
Q

What does an enzyme do to catalyze a reaction? (what changes, what stays the same)

A

Changes:
- lower energy barrier (takes less energy for the reaction to occur)
Doesn’t change:
- reactants or products
- free energy
- whether the reaction releases or absorbs energy

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4
Q

What things can impact enzyme activity?

A
  • enzyme concentration
  • substrate concentration
  • temperature
  • pH
  • enzyme inhibitors
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5
Q

How does enzyme concentration impact enzyme activity?

A

more enzymes = increase in enzyme reaction rate, substrates interact/collide with enzymes more often

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6
Q

How does substrate concentration impact enzyme activity?

A

more substrates = increase in reaction rate, enzymes and substrates interact/collide more often

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7
Q

How does temperature impact enzyme activity?

A
  • enzymes have an optimal temp for maximum reaction rate
  • low temps = slower rate
  • high temps = denaturation if too high
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8
Q

How does pH impact enzyme activity?

A
  • enzymes have an optimal pH for maximum reaction rate
  • high pH = decreased enzyme activity
  • low pH levels can cause denaturation of the enzyme
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9
Q

How do inhibitors impact enzyme activity?

A

General
- certain chemicals inhibit enzyme function
- covalent bonds = irreversible inhibition
- weak interactions = reversible
Competitive
- looks like substrate and binds to the active site, stops the real substrate
- increasing substrate concentrations can overcome bonds
Noncompetitive
- not bound to the active site
- change the shape of the enzyme making it less effective

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10
Q

Why do living things not defy the second law of thermodynamics?

A

???
- all reactions release a small amount of heat energy that contributes to entropy
- metabolism releases energy
- ordered structures deteriorate over time and need to be replaced
???

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11
Q

What are the inputs and outputs of a light dependent reaction?

A

Inputs:
Water (H2O), light energy, NADP+, ADP + phosphate ion
Outputs:
NADPH, ATP, oxygen

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12
Q

What are the inputs and outputs of a light independent reaction? (Calvin Cycle)

A

Inputs:
CO2, ATP, NADPH
Outputs:
G3P (a 3 carbon sugar) which will later be glucose, ADP + phosphate ion, NADP+

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13
Q

Where does the light dependent reaction take place?

A

Thylakoids of chloroplasts

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14
Q

Where does the light independent reaction take place? (Calvin Cycle)

A

Stroma of chloroplasts

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15
Q

What is the main purpose of the light dependent reaction?

A

Captures energy from the sun to create ATP and NADPH for use in the light independent reaction

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16
Q

What is the main purpose of the light independent reaction? (Calvin Cycle)

A

Uses ATP and NADPH to produce carbs/sugars from CO2 taken in

17
Q

What are the photosystems and why are they important?

A
  • they are proteins embedded in the thylakoid membranes
  • chloropyll pigments absorb light to excite electrons
18
Q

What would happen if the proton gradient in photosynthesis was not working?

A

If the proton gradient stops working then ATP will not longer be produced for the light independent reaction to occur

19
Q

What is the importance of the proton gradient in photosynthesis and how is it created?

A
  • As electrons are transferred down the ETC H+ ions are moved into the thylakoid
  • the H+ ions then leave the thylakoid through ATP synthase from high to low concentration to create ATP
20
Q

What is the origin of photosynthesis?

A
  • First evolved in prokaryotic cells
  • moved to eukaryotic cells due to endosymbiosis
21
Q

What are the inputs and outputs of glycolysis?

A

Inputs:
Glucose
Outputs:
2 pyruvate, 2 ATP, 2 NADH

22
Q

Where does glycolysis take place?

A

In the cytosol

23
Q

What is the main purpose of glycolysis?

A

The first step for both cellular respiration and fermentation, extract electrons and move them to NADH And FADH2 which is used in the ETC

24
Q

What are the inputs and outputs of the citric acid/krebs cycle?

A

Inputs:
Acetyl CoA
Outputs:
NADH, FADH2 and ATP, CO2

25
Q

Where does the citric acid/krebs cycle take place?

A

The mitochondrial matrix

26
Q

What is the main purpose of the citric acid/krebs cycle?

A

Extract electrons and move them to NADH and FADH2 which is used in the ETC

27
Q

Where is the electron transport chain?

A

The inner membrane of the mitochondria

28
Q

What is the main purpose of the electron transport chain?

A
  • series of small reactions that release small amounts of energy to bring in H+ ions
  • Oxygen accepts the electron at the end and forms water
29
Q

What is oxidative phosporylation and what is it’s main purpose?

A
  • As the electron goes down the ETC H+/protons pass across the membrane to reach equilibrium
  • ATP synthase forms ATP from ADP + P
  • Oxidation = NADH/FADH2 lose electrons
  • Phosphorylation = ADP + P –> ATP
30
Q

What are the inputs and outputs of fermentation?

A

Inputs:
glucose, 2 ATP
Outputs:
Lactic acid or alcohol and CO2

31
Q

Aerobic vs anaerobic respiration

A

Anaerobic = needs oxygen (most of cellular respiration)
Aerobic = doesn’t need oxygen (fermentation)

32
Q

What is the importance of the proton gradient and how is it created? (cellular respiration)

A
33
Q

What can the proton gradient be used for other than the production of ATP?

A

Energy from the proton gradient can be used to generate heat/regulate body temp instead of going through ATP Synthase

34
Q

What is unique about fermentation? Why is that important?

A

Doesn’t require oxygen, starts with glycolysis but doesn’t go through the Krebs cycle or the ETC

35
Q

What is the main goal of cellular respiration and fermentation?

A

To make ATP for use in the cell from stored sugars and carbs

36
Q

What is the main goal of photosynthesis?

A

Allows plants to make food using light energy which is converted into chemical energy

37
Q

Why is ATP important?

A

When it is converted into ADP it releases energy for use within the cell

38
Q

Endergonic vs exergonic

A

Endergonic
- releases energy (still requires a little energy input for the reaction to occur)
- spontaneous
- products have LESS free energy than reactants
Exergonic
- absorbs energy
- non-spontaneous
- products have MORE free energy than reactants

39
Q

Oxidation vs reduction

A

Oxidation = losing electrons
reduction = gaining electrons