Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biochemistry > Final Review > Flashcards

Final Review Flashcards

(62 cards)

Start Studying
1
Q

How does insulin activate glycogen synthase?

A

By inactivating GSK3 & activating PP1

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

Glucagon stimulates _________ and _________ while blocking glycolysis

A

glycogen breakdown and gluconeogenesis

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

What does it mean to say the membrane lipid bilayer is amphipathic

A

it contains both hydrophilic and hydrophobic regions

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

What metabolite links glycolysis and CAC?

A

pyruvate

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

Epinephrine causes an _______ of blood glucose levels while insulin causes an ________ of BGL

A

epinephrine causes an increase of BGL and insulin causes a decrease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

main composition of lipid bilayer

A

phospholipids & sphingolipids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

which leaflet of the membrane is more positively charged

A

outer leaflet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what enzymes catalyze trans bilayer flip flop diffusion of lipids

A

lipid translocators (flippases, floppases, scramblaes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Lipid raft composition

A

glycosphingolipids and cholesterol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How is the membrane able to undergo fusion with other membranes w/out losing continuity?

A

changes in curvature
* curvature is required for cell fusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

GPCRs are active when

A

GTP bound

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

2nd messengers

A

cAMP, diacylglycerol, IP3 or Ca2+
- either inhibit or activate one or more downstream targets usually protein kinases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does it mean that stimulation of adenylyl cyclase is self-limiting

A

Gs alpha has intrinsic GTPase activity that switches Gs alpha into its inactive form by converting the bound GTP for GDP
** stimulated by GTPase activator protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

3 ways to terminate the Beta Adrenergic System

A
  1. desensitization - [epinephrine] in blood drops below the Kd for its receptor
  2. Hydrolysis of GTP–>GDP via intrinsic GTPase activity
  3. removing cAMP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

_____ Hormone made in the adrenal glands that mediates the body’s stress response by mobilizing E in the form of glucose
– causes an increase in blood glucose levels

A

epinephrine

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

_____ causes a decrease in blood glucose levels

A

insulin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How does cAMP activate PKA

A

cAMP binds at the two R subunits causing them to undergo a conformational change that moves the autoinhibitory domain out of the catalytic domain causing the two R2C2 complex to dissociate and yield two catalytically active C subunits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

PLC cleaves PIP2 into what two things

A

Diacylglycerol and IP3

IP3 causes the release of Ca2+ and together with Diacylglycerol, Ca2+ and DAG activate pKC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What molecules regulate the desensitization of the epinephrine pathway

A

BARK and Beta Arrestin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

PKA is localized to particular structures by its anchoring/adaptor protein _____

A

AKAP5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Why are the inside of cells negatively charged

A

due to the asymmetric transport of cations by the NA+K+ATPase (3 Na+ go out as 2K+ come in)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what regulates the timing of the cell cycle

A

cyclin-dependent kinases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the first two steps of gluconeogenesis

A
  1. pyruvate converted to oxaloacetate via pyruvate carboxylase
  2. oxaloacetatee converted to PEP (phosphoenolpyruvate) via PEP carboxylase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Purpose of gluconeogenesis

A

allows for the generation of glucose when glycogen stores have been depleted (starvation/excercise)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Why does oxaloacetate need tot be converted into PEP or malate during gluconeogenesis?
b/c oxaloacetate cannot escape the inner mitochondrial membrane but malate,PEP and pyruvate can
26
Hexokinase I,II,III are all regulated by?
Glucose-6-phosphate
27
Hexokinase IV is regulated (inhibited) by
Fructose-6-phosphate
28
What enzyme catalyzes the conversion of F-6-P to F-1,6-BP
PFK-1
29
What increases PFK-1 activity (thus promoting glycolysis)
AMP & ADP
30
What inhibits PFK-1, inhibiting glycolysis
ATP, citrate
31
What converts PEP to pyruvate
pyruvate kinase +ADP and Pi
32
Why is pyruvate converted into PEP
when fatty acids are available and when acetyl-coA signals that no more E production is needed
33
products of the pentose phosphate pathway
NADPH & Ribose-5-phosphate which are necessary for producing fatty acids, cholesterol and sterols
34
what inhibits pentose phosphate pathway
NADPH
35
Transaminations - what is the cofactor and what is the enzyme
catalyzed by aminotransferases & PLP (pyridoxal phosphate) is the cofactor
36
What is a transamination reaction
transfer of an alpha amino group from an alpha amino acid to an alpha-keto acid
37
What is a transamination reaction?
transfer of an alpha amino group from an alpha amino acid to an alpha-keto acid
38
What is the purpose of step 2 in glycolysis?
makes the next steps in the reaction require less energy –C1 of fructose is easier to phosphorylate by PFK , allows for symmetrical cleavage by aldolase
39
What is the purpose of step 3 in glycolysis?
the 2nd phosphorylation converts fructose-6-phosphate to fructose-1,6-bisphosphate – this is the first committed step of glycolysis…b/c fructose 1,6 bisphosphate is committed to becoming pyruvate
40
What is the purpose of step 4 in glycolysis?
Step 4 is the aldol cleavage of a 6-carbon sugar into two 3-carbon sugars GAP and DAP
41
What is the purpose of step 5 in glycolysis?
This step completes the preparatory phase of glycolysis - allows glycolysis to proceed to the payoff phase by a single chemical pathway conversion of dihydroxyacetone phosphate to GAP (glyceraldehyde-3-phosphate)
42
What is the purpose of step 6 in glycolysis?
– incorporates inorganic phosphate – the first energy-yielding step in glycolysis, produced NADH
43
Pathway that converts pyruvate (and its related 3 and 4 carbon compounds) to glucose
gluconeogenesis
44
What molecules in gluconeogenesis are permeable to the mitochondrial membrane…which are impermeable
Permeable molecules = Malate, PEP, pyruvate IMpermeable = oxaloacetate
45
What is oxaloacetate converted to in order to allow for transport to the cytosol for gluconeogenesis?
oxaloacetate can be converted to PEP or malate
46
A reason why gluconeogenesis is physiologically necessary
The brain, NS, and red blood cells can only generate ATP from glucose
47
In mammals, where is the main site of gluconeogenesis
liver
48
How is phosphofructokinase-1 (PFK-1) regulated?
PFK-1 is regulated by the binding of ATP to an allosteric site - this occurs when there is an excess in ATP Citrate inhibits PFK-1 by increasing the inhibitory effects of ATP – causes a smaller concentration of ATP to seem like more
49
How is (FBPase) fructose 1,6 bisphosphate ALLOSTERICALY regulated (inhibited)
high concentrations of AMP (low ATP) inhibit FBPase –> thus slowing glucose synthesis high ATP concentrations slow glycolysis and speed up gluconeogenesis
50
How does F26BP regulate PFK-1
Binds to PFK-1 and increases its affinity for fructose-6-phosphate
51
Hows does F26BP regulate FPBase-1?
binds to FPBase-1 and REDUCES its affinity for substrate
52
Under aerobic conditions what does pyruvate become?
pyruvate gets oxidized to acetyl-coA
53
High ______ concentrations inhibit the committed step of glycolysis to prevent excess glucose degradation
ATP
54
3 things that affect the rates of biochemical reactions
1. Concentration of reactants Rate = k[reactants] 2. activity of the catalyst the concentration of the enzyme & intrinsic activity of the enzyme 3. Concentration of effectors
55
What is the breakdown of cellular glycogen to glucose-1-phosphate ?
glycogenolysis
56
What enzyme performs the isomerization of glucose 1-phosphate to glucose-6-phosphate
Phosphaglucomutase
57
What substrate serves as the primer for glycogen synthesis
glycogenin
58
What stimulates the conversion of phosphorylase b (inactive) into a (active)?
breaking down glycogen = cells need more E * epinephrine (muscle activity) * glucagon in liver
59
What molecule converts glycogen synthase a (active) to synthase b (inactive) by adding phosphoryl groups to three serine residues on synthase a
Inactive glycogen synthase = stop using glucose to make glycogen GSK3: Glycogen synthase kinase 3
60
What inactivates GSK3 (which itself inactivates glycogen synthase)
insulin bc inslun says hey we have exttra glucose time to sttorage that bitch
61
What must happen before glycogen synthase kinase 3 (GSK3) can phosphorylate glycogen synthase?
Casein Kinase II (CKII) must first phosphorylate the glycogen synthase on a nearby residue
62
Glycogen breakdown is catalyzed by?
glycogen phosphorylase

Biochemistry (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions