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Flashcards in Biology Class 1 Deck (45)
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31

Exergonic vs Endergonic

Exergonic (-) - energy is exiting system
Endergonic (+) - energy is added to system

32

Endothermic vs Exothermic

Endothermic (+ΔH) - inputting heat
Exothermic (-ΔH) - liberating heat

33

What are two ways enzymes can be turned on or off?

1. Phosphorylation
2. Allosteric Activator - turns on
Allosteric Inhibitor - turns off

34

What does Vmax depend on?

1. Type of enzyme
2. [E]

35

What is Km

[S] required for 1/2 of Vmax
As affinity for [E] and [S] increases = Km decreases

36

Competitive Inhibition

Binds at the active site
Vmax will stay the same
Km will increase

37

Noncompetitive Inhibition

Binds at the allosteric site
Vmas will decrease
Km will stay the same

38

Uncompetitive Inhibition

Binds at ES complex
Vmax will decrease
Km will decrease

39

Mixed Inhibition

Binds at allosteric site
Vmax will decrease
Km will decrease (if binded to ES complex) or increase (if binded to enzyme alone)

40

9 essential amino acids that cannot be synthesized by adult humans & must be obtained from diet

Lysine
Histidine
Threonine
Valine
Leucine
Isoleucine
Phenylalanine
Tryptophan
Methionine

41

Purpose of reaction coupling

- Allows for generation of products that would not normally be formed spontaneously
- Reaction coupling allows for a spontaneous process to drive a nonspontaneous process to make the overall reaction spontaneous
- As this is affecting a thermodynamic property, it is unlikely to have an impact on kinetics (reaction rates would not increase, but would be limited by the slow reaction)

42

What is a direct enzymatic regulation?

- Protein hydrolysis, phosphorylation/dephosphorylation, allosteric activity (even downstream) NOT modification of transcription factors

43

What happens when a molecule covalently links to an enzyme site?

This would be known as an irreversible inhibitor; negligible enzyme activity

44

How is dietary fat broken down?

Dietary fat is broken into 2 fatty acids and 1 monoglyceride prior to absorption. Due to the activity of lipase, triglycerides are broken down into two fatty acids and a monoglyceride before absorption and ultimate reassembly into a triglyceride in the enterocyte.

45

Which linkage can be cleaved by human amylase?

B(1-6) (starch).

B(1-4) cannot & will pass undigested (cellulose)