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Biol 102: Exam > Week 3 > Flashcards

Week 3 Flashcards

1
Q

Define Metabolism

A

the complete set of chemical reactions that can be performed in an organism. It is arranged as metabolic pathways, that can be intersecting, linear, etc.

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2
Q

What is catabolic and anabolic?

A

Catabolic is breakdown, while anabolic is build up.

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3
Q

What are the forms of energy?

A

Kinetic, thermal, potential, and chemical.

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4
Q

Define thermodynamics

A

the study of energy and its transformations

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5
Q

What is the difference between a system and surroundings?

A

A system refers to what is being studied, and the surroundings is everything else.

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6
Q

Define the first and second law of thermodynamics.

A

First: energy cannot be created or destroyed

Second: every energy transfer increases the entropy within the universe (disorder)

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7
Q

What is gibbs free energy? What is the equation.

A

It is the part of the system’s energy that can preform work.

G=H-T

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8
Q

What is Activation Energy

A

Energy required to start a chemical reaction, and determines the rate of a reaction. The more activation energy, the slower the reaction.

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9
Q

Transition state definition

A

molecules in an unstable condition, have enough energy to break and reform new bonds.

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10
Q

What are enzymes?

A

they are macromolecules that act as biological catalysts. Cells can contain large numbers of them, and we will focus on protein ones. Are found within specific organelles (ex. mitochondira).

Contains an active site where reactants of an enzyme bind.

Could require cofactors (inorganic) or coenzymes (organic).

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11
Q

What is a catalyst?

A

Speeds up a chemical reaction, but is not consumed during the reaction. Decreases the activation energy, without affecting gibbs free energy.

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12
Q

What is a substrate?

A

The reactant an enzyme acts on.

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13
Q

What is substrate speceficity?

A

Enzyme can only reckognize a certain number of substrates which is determined by the shape of the enzyme (active site)

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14
Q

What is the active site

A

Where the substrate binds and where the reaction occurs. Has a complementary size and charge for specefic substrates.

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15
Q

What is induced fit?

A

Changes in the active site to really “fit” the substrate once it has binded.

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16
Q

How can an enzymes activity be influenced?

A

Temperature and pH.

Explains why body temperature has to be highly regulated, or it can result in the denaturing of stuff, while blocks metabolism.

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17
Q

What is a multi-enzyme complex?

A

They carry out all of the steps of a metabolic pathway. Contains everything you need. If it was not organized like this, would slow down the metabolic processes that need to occur, makes this much more efficient.

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18
Q

What are the two types of inhibitors?

A

Competitive and non competitve inhibitors

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19
Q

Define competitive inhibitors

A

block the active site by directly binding to them.

20
Q

Define non competitive inhibitors

A

interacts with an enzyme away from the active site, but changes the site of the active site in the process, meaning the substrate can no longer bind.

21
Q

What is allosteric regulation?

A

it is the binding of a regulatory molecule to a protein at one site that affects the function at a different site.

It can activate or inhibit an enzyme.

Feedback inhibition is a type of allosteric regulation.

22
Q

Define feedback inhibition

A

Where the regulatory molecule is the end product of the same metabolic pathway. This is a good way of controlling the concentration of a metabolite in the cell. Something would bind to the enzyme to change what is being produced, and whats produced is the regulatory molecule.

23
Q

What are the three kinds of work that a cell does?

A

Chemical, transport, and mechanical

24
Q

How is work accomplished within the cell? Explain.

A

Done through energy coupling.

The energy released from an exergonic reaction is used to power an endergonic one.

Generally mediated through ATP, as the energy generated from exergonic reactions is sued to synthesize ATP from ADP and inorganic molecules, and this releases energy that is used for cellular work, while also remaking ADP and phosphates.

25
Q

What makes ATP so high energy?

A

Their phosphate groups. As they are high energy, and contain repulsion of negative charges. Energy does not come from breaking bonds, but from forming them.

26
Q

What can ATP hydrolysis be used to do?

A

Can be used to perform work. Transport and mechanical work.

27
Q

What are the two types of cellular respiration?

A

Aerboic and anaerobic.

28
Q

What is the chain for aerobic respiration?

A

Glycolysis, pyruvate oxidation, citric acid cycle, oxidative phosphorolation (electron transport chain and chemisomosis).

29
Q

Define cellular respiration.

A

The catabolic pathways that breakdown organic compounds into waste products and energy.

compounds with C-H bonds are reduced to form C-O bonds. Meaning that molecules with many C-H bonds are good sources of energy for that reason. Cellular respiration produces energy through oxidizing compounds with C-H bonds to produce products with C-O bonds.

30
Q

What are oxidation-reduction reactions?

A

chemical reactions involving the transfer of eletrons, which form the basis of extracting energy from organic compounds.

Oxidation: loss of electrons, one that is oxidizied is referred to ass the reducing agent.

Reduction: gain of electrons, one that is reduced is referred to as the oxidizing agent.

31
Q

What is NAD+ and NADH. What are the differences and functions?

A

The most common type of electron carrier. This is how electrons are passed through cellular respiration.

NAD+ is the oxidized version of NADH (meaning it has one less electron), while NADH is the reduced version (with an extra electron).

32
Q

What are degydrogenase reactions? What is its enzyme.

A

redox reactions that form NADH are referred to as dehydrogenase reactions.

Dehydrogenaseses is the enzyme that does this reaction. transfers two electrons and a proton from an organic compound to NAD+, which produces NADH.

33
Q

Where does glycolysis occur?

A

In the cytosol, both both prokaryotes and eukaroytes.

34
Q

Where does pyruvate oxidation and citric acid cycle occur?

A

Eukaroyotes: in the mitochondrial matrix

Pro: cytoplasm

35
Q

Where does the oxidative phosphorylation occur?

A

Eukaroyotes: inner membrane of mitochondira

Pro: plasma membrane

36
Q

Explain glycolysis.

A

breakdown of glucose into two molecules of pyruvate. The two pathways are EMP and ED, ED being older.

Includes two phases:
-energy investement phase (requires ATP)
-energy payoff phase (produces two ATP)

Glucose+ 2ATP +2NAD+ + 2phosphate -> 2 pyruvate + 2NADH + 2ATP + 2H+ + 2H2O

37
Q

what is substrate level phosphorlyation?

A

formation of ATP from ADP and a phosphorylated intermediate. Which means the transfer of a phosphate group.

38
Q

What is pyruvate oxidation? Define and explain.

A

The second stage of aerobic respiration.

Occurs in the mitochondrial matrix (euk) or cytosol (pro).

Involves three reactions catalyzed by a multi-enzyme complex. For this one, three enzymes are requird to convert pyruvate into Acetyl-coA. The pyruvate is oxidized into Acetyl-coA so that it can be used in the citric acid cycle.

The following is per one pyruvate (would be doubled per glucose):

pyruvate + NAD+ +2CoA -> NADH + H+ + CO2 + Acetly-CoA

39
Q

What is the citric acid cycle? Define and explain.

A

Also known as the krebs cycle.

It starts and ends with oxaloacetate, so consdiered a cycle.

Two carbons from Acetyl-coA are transferred to a molecule of oxaloacetate to produce citrate. There are 4 dehydrogenase reactions in the cycle, which means that 4 NADH are produced.

Per each acetly-coA (doubled for each glucose):

acetly-coA + 3NAD+ + FAD + ADP + phosphate + H2O -> ATP +FADH2 + 3NADH + H+ + 2 CO2 + CoA

40
Q

What is oxidative phosphorylation?

A

Final stage of aerobic respiration.

The synthesis of ATP through the energy released by the transfer of electrons from NADH and FADH2 to O2 (the final electron acceptor).

Includes two stages: electron transport chain and chemisosmosis.

41
Q

Define and explain the electron transport chain.

A

The first stage of oxidative phosphorylation.

It consists of 4 multi protein complexes. It is the transfer of electrons to O2 through a series of redox reactions involving multiprotein complexes tightly bound to non protein prosthetic groups (type of cofactor whos defining feature is that they are tightly bound to the enzyme, which is different than other cofactors).

Some of the redox reactions are coupled to the export of protons which establish a proton motive force. This contriibutes to ATP production by establishing this, and this repersents a form of PE as these are then used later on to produce ATP from chemiosmosis.

Details:

  • ubiqionon is the final electron carrier and is the only one that is not a protein
  • for every NADH molecule a total of 10 protons are exported across the membrane.

-for every FADH2, it is only 6.

-proton export results in proton electrochemical gradient being formed, with the concentration of protons outside of the membrane much higher than inside.

42
Q

Define and explain chemiosmosis.

A

Second stage of oxidative phosphorylation.

The diffusion of protons down the electrochemical gradient and using the energy released by this proton movement to drive cellular work. Provides the energy for ATP production by the enzyme ATP synthase.

Protons moving down their electrochemical graident will move through a channel of ATP synthease. The proton binding on the ATP synthase causes the rotor to spin, and the spinning of the rotor leads to the phosphorylation of ADP to produce ATP. Once one full turn has happened, the protons are then released into the inside of the membrane.

Each molecule of NADH leads to the production of 2.5 ATP molecules being formed (10 protons).

Each molecule of FADH2 leads to 1.5 ATP being formed (6 protons)

43
Q

Overall how much ATP is made?

A

30-32 per molecule of glucose.

Number variation of 2 because it depends which electron carrier is used. if NADH is used, two more are produced, but if FADH2, less are produced.

34% effiency.

44
Q

How is cellular respiration regulated?

A

phosphofructokinase, ATP, citrate, and AMP.

Phosphofructokinase is part of the energy investement phase.

Positively regulated by: AMP

Negatively regulated by: ATP and citrate

Rate of cellular respiration is dependent on the overall ratio of these compounds in the cytoplasm.

45
Q

Define anaerobic respiration and details.

A

02 as the terminal electron acceptor is replaced by another molecule such as sulphate, methane, or nitrate.

Less efficient, as these molecules are weaker oxidizing agents than O2.

Therefore less amounts of ATP are produced.

46
Q

Define fermentation and its details.

A

anaerobic respiration, when no oxygen.

ONLY 2 ATP PRODUCED NET.

skips the electron transport chain, relys fully on substrate level phosphorylation (glycolysis) for ATP production. Is able to recycle NADH to NAD+ via electron transfer. If this was not able to be done, then glycolysis would completely stop after all of the NAD+ had been used. Essential for glycolysis to continue.

Includes lactic acid and alcohol fermentation.

47
Q

Lactic acid fermentation.

A

Occurs in our muscle cells when unable to get oxygen from the blood to support cellular respiration.

Biol 102: Exam (3 decks)

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