Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIOL112 > Lecture 10: Glycolosis > Flashcards

Lecture 10: Glycolosis Flashcards

1
Q

Feedback inhibition

A
  • regulated the whole metabolic pathway (production of amino acids)
    • Metabolic pathway includes:
    1. threonine
    2. alpha-ketobutyrate
    3. Isoleucine
  • each rxn there there is an enzyme
  • Isoleucine will bind to the first enzyme in order to inhibit it
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Multiple Feedback Control

A
  • allows cells to adjust the ratio of different compounds (e.g amino acids)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Enzyme Regulation

A

a) Competitive Inhibition

b) Allosteric Regulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Competitive inhibition

A
  • The substrates cannot
    bind when a regulatory
    molecule binds to the
    enzyme’s active site.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Allosteric Regulation

A 
• Allosteric Activation:
- The active site becomes
available to the substrates
when a regulatory molecule binds to a different site on the enzyme.
or:
• Allosteric Inhibition:
- The active site becomes
unavailable to the substrates when a regulatory molecule
binds to a different site on
the enzyme.
*each time, the shape of the enzyme changes*
*most common type of regulation*
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How is Allosteric Inhibition more efficient?

A
  • comes down to number of regulator molecules that you need
  • Competitive inhibition you need 10 million molecules and maybe 1 million regulators
  • Allosteric regulator you have 1 regulator: 10 molecules (therefore, less energy)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Cooperative Allosteric Transition

A
  • occurs with two or more subunits
  • inhibitor can bind to the enzyme in the place of a substrate.
  • It is a difficult transition for the inhibitor to be added, when the enzymes already binded
  • it is an easy transition when one inhibitor and one substrate are in and the inhibitor can be added.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Cooperative Allostery

A

• when multiple subunits bind together

  • results in different reaction curve
  • the more subunits, the steeper the slope meaning that the enzyme activity lowers a lot faster with more subunits
  • some delay at the beginning because it takes a while to bind (first is hardest, then gets easier)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Firs step in Metabolic Pathway

A
  • nearly always a multisubunit enzyme negatively regulated by cooperative allostery
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Glycolosis

A
  • when glucose is broken down, it produces energy - must be done in little steps to minimize the amount of energy lost
  • complete oxidation of glucose is exergonic
  • about half of the energy from glucose is collected in ATP (endergonic)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Energy for Life

A
  • sun allows photosynthesis which allows for stored chemical energy which allows for glycolysis
  • glycolysis can be aerobic or anaerobic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Aerobic Glycolysis: Cellular Respiration

A
  • complete oxidation
  • waste products: H2O, CO2
  • net energy trapped: 29 ATP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Anaerobic Glycolysis: Fermentation

A
  • incomplete oxidation
  • waste products: organic compound
  • net energy trapped: 2 ATP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Redox Reactions

A

• Transfer electrons
• Made up of 2 half reactions/redox pairs . (meaning one side electrons are collected, then transferred)
- A gain of electrons or hydrogen atoms is called reduction.
- The loss of electrons or hydrogen atoms is called oxidation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How do you recognize oxidations?

A
  • Fe+2 to Fe+3

- adding a hydrogen meaning you are oxidization (removing an electron, thus increasing the hydrogens)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Oxidation of Organic Molecules

A
  • decreases the number of C-H bonds

- due to the attraction the electrons have to oxygen atoms, more than carbon.

17
Q

NAD

A
  • cofactor
  • essential electron carrier in cellular redox reactions
  • intermediate within the reaction
18
Q

NAD+

A
  • gives up electrons (from glucose) to oxygen (electronegative acceptor)
  • Has alternating double bonds that are energetically favoured because of the electrons of all 3 electron pairs form a common electron cloud. This makes it very stable
  • forms into NAHH by breaking down glucose and accepting electrons (i.e getting reduced)
19
Q

Oxidation of NADH with O2 as electron accepter

A 
- exergonic
NADH + H+ + 1/2 O2 → NAD+ + H2O
• Two half reactions or redox pairs:
1. NADH	NAD+ + H+ + 2e- (oxidation)
2. 1/2 O2 + 2H+ + 2e-	H2O (reduction)
- NADH gives up electrons, oxygen takes those and becomes water.
20
Q

Redox potential

A
  • the tendency to lose or gain electrons
  • a positive redox potential means that thy will have a tendency to gain electrons (become reduced)
  • a negative redox potential means they will have a tendency to loose electrons (become oxidized)
21
Q

Stages of Glycolysis

A
  1. Investment of ATP to activate the sugar followed by splitting of C6 into 2x C3
  2. Oxidation of C3 giving NADH + H+ and ATP followed by recovery of initial ATP investment (investment is required to rearrange the sugar to be oxidized)
22
Q

Glycolysis coverts glucose to pyruvate (Part 1)

A
  • First reaction is catalyzed by HEXOKINASE - forms G6P (adds a phosphate bond)
  • Second reaction is catalyzed by PHOSPHOHEXOSE ISOMERASE (creates symmetry for breakup into two 3-C molecules- forms F6P)
  • Third reaction is catalyzed by PHOSPHOFRUCTOKINASE (catalyses based on energy levels in cells) (adds another phosphate group to the molecules to make it more symmetrical- forms FBP)
23
Q

Glycolysis coverts glucose to pyruvate (Part 2)

A
  • takes FBP and splits into 2 3-C molecules called G3P
24
Q

Glycolysis coverts glucose to pyruvate (Part3)

A
  • G3P is oxidized
  • NAD+ is reduced to NADH +H+
  • this exergonic reaction releases enough energy to phosphorylate the molecules, forming BPG
  • 1,3-bisphosphoglycerate donates one of its phosphate groups to ADP making a molecule of ATP and turning into 3-
    phosphoglycerate in the process.
25
Q

Glycolysis coverts glucose to pyruvate (Part 4)

A
  • 3- phosphoglycerate is converted into its isomer, 2-phosphoglycerate.
  • 2-phosphoglycerate loses 2 molecules of water, becoming phosphoenolpyruvate (PEP). PEP is an unstable molecule, poised to lose its phosphate group in the final step of glycolysis.
  • PEPP, readily donates its phosphate group to ADP, making a second molecule ATP. As it loses its phosphate, PEP is converted pyruvate; the end product of glycolysis. (overall there are 2 pyruvate)
26
Q

Substrate- level phosphorylation

A
  • results in the formation of ATP or GTP by the direct transfer of a phosphoryl (PO3) group to ADP or GDP
27
Q

Unfavourable reactions

A
  • Have positive ∆G

* can be directly coupled to favourable ones (hydrolysis of ATP) or indirectly by sequential coupling.

28
Q

Where does pyruvate Oxidation occur?

A

• In mitochondria

  • carboxyl group is removed (released as CO2)
  • NADH is released
  • NAD+ is added along with Coenzyme A
  • this results in Acetyl Coenzyme A

BIOL112 (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions