Refresher Course Flashcards
(144 cards)
1
Q
What are metabolic pathways?
A
A series of chemical reactions that perform an essential task for our system.
2
Q
What dictates the direction of a metabolic pathway?
A
The favorability of the reactions of the pathway.
3
Q
What does ΔG > 0 indicate?
A
Endergonic reaction, meaning the reverse reaction is favored.
4
Q
What does ΔG < 0 indicate?
A
Exergonic reaction, meaning the forward reaction is favored.
5
Q
What is the equation for Gibbs free energy?
A
ΔG = ΔH - TΔS.
6
Q
What does ΔG depend on?
A
Position in reaction and prevailing conditions of the system (Q).
7
Q
What is the significance of ΔG°’?
A
It is a reference state under standard state conditions.
8
Q
Fill in the blank: The energetic barrier to transition from diamond to graphite is extremely _______.
A
high
9
Q
What are ‘Traffic Lights’ in metabolic pathways?
A
Regulation points that drive the pathways and are essentially irreversible.
10
Q
What role do high-energy molecules play in metabolism?
A
They act as coupling agents to drive reactions forward.
11
Q
What type of reactions are responsible for a major portion of the work done in living cells?
A
Oxidation-reduction reactions.
12
Q
True or False: Thermodynamics influences the rate of reaction.
A
False
13
Q
What do enzymes provide to lower activation energy?
A
Binding energy.
14
Q
What factors control the output or flux of metabolic pathways?
A
The number of enzymes and their kinetic parameters.
15
Q
Fill in the blank: Enzymes mediate the rate that a ________ occurs.
A
reaction
16
Q
What is the relationship between thermodynamics and kinetics in metabolism?
A
Thermodynamics controls direction; kinetics controls rate.
17
Q
What is the effect of increasing creatine in myocytes during workouts?
A
It increases ATP levels, aiding in muscle building.
18
Q
What is the role of activated metabolites like ATP and Acetyl-CoA in metabolism?
A
They are used in irreversible steps that drive pathways.
19
Q
How do changes in metabolite concentrations affect metabolic pathways?
A
They can alter the favorability of reactions and the direction pathways flow.
20
Q
What is metabolism?
A
Compilation of chemical reactions responsible for energy transduction, synthesis of complex biomolecules, and functional work.
21
Q
What is the role of energy in living systems?
A
Energy is contained in the bonds of molecules, extracted and transferred to universal energy carriers.
22
Q
What are biorefineries in the context of human biology?
A
Our bodies convert raw chemical energy (food) into fuel molecules and building materials to maintain homeostasis.
23
Q
What are chemotrophs?
A
Organisms that derive energy from chemical sources.
24
Q
List common fuel molecules utilized in cellular processes.
A
- ATP
- Acetyl-CoA
- NAD(P)H
- Phosphorylated molecules
25
What is the universal energy currency of the cell?
Adenosine Triphosphate (ATP)
26
What is the function of mitochondria?
Generator of ATP to fuel the cellular system.
27
What are transporters?
Proteins that facilitate the transport of specific substrates across membranes.
28
What is the difference between transporters and channels?
* Transporters bind substrates with high specificity, are saturable, and catalyze transport below the rate of diffusion.
* Channels allow movement of ions and are not saturable.
29
What are catabolic pathways?
Pathways that break down complex molecules to harvest energy and/or make simpler molecules.
30
What are anabolic pathways?
Pathways that utilize energy and/or simple molecules to build complex biomolecules.
31
What is glycolysis?
Central pathway for carbohydrate metabolism with 10 steps, each catalyzed by an enzyme.
32
What is the net gain of ATP and NADH from glycolysis?
2 ATP and 2 NADH.
33
Fill in the blank: The final product of glycolysis is _______.
pyruvate
34
What are GLUTs?
Transporters for glucose that vary by sugar type and tissue specificity.
35
What is the significance of step 1 in glycolysis?
Commits glucose to the cell and prevents it from exiting.
36
What is the purpose of the citric acid cycle?
To extract electrons from carbon and transfer them to NAD+ and FAD.
37
What are the end products of the complete oxidation of glucose?
32 ATP.
38
What is the role of NADH and FADH2 in cellular respiration?
They are reduced cofactors that power the electron transport chain.
39
True or False: The electron transport chain requires oxygen.
True.
40
What happens during beta-oxidation?
Fatty acids are broken down into acetyl-CoA.
41
What is the pentose phosphate pathway?
An alternate pathway for glucose metabolism to extract NADPH and ribose.
42
What are amino acids primarily used for in metabolism?
Building blocks for proteins and carriers of nitrogen.
43
Fill in the blank: The degradation of amino acids starts with _______ removal.
nitrogen
44
What are the common metabolic intermediates derived from amino acids?
* pyruvate
* α-ketoglutarate
* succinyl-CoA
* fumarate
* oxaloacetate
* acetyl-CoA
* acetoacetate
45
What is the significance of the urea cycle?
It removes excess nitrogen waste from amino acid catabolism.
46
What is the impact of low carnitine levels on metabolism?
It can lead to fatigue and muscle wasting due to impaired fatty acid metabolism.
47
What do anabolic pathways produce?
Important cellular components and perform functional work that sustain living systems
48
What do anabolic pathways utilize?
Molecular building blocks and energy derived from catabolic pathways
49
How do anabolic pathways interact with catabolic pathways?
They reuse enzymes from catabolic pathways for thermodynamically reversible steps
50
What is required to bypass thermodynamically irreversible steps of catabolic pathways?
Alternate reactions and enzymes
51
Where are anabolic pathways often located?
Different compartments of the cell and are often tissue/cell specific
52
What is gluconeogenesis?
The synthesis of glucose from non-carbohydrate sources
53
What is the sole fuel source for red blood cells?
Glucose
54
Which organs can synthesize glucose to support the system?
Liver and kidneys
55
What is the role of tissue-specific enzymes in gluconeogenesis?
They determine the pathway's activity and presence
56
What regulates gluconeogenesis?
Conditions that dictate pathway activity and presence, molecular regulators, and hormone signaling
57
What does the presence of glucose trigger?
Glycogenesis when glucose is abundant
58
Fill in the blank: Glycogen synthase is activated by _______.
Insulin
59
What is the primary storage form of fatty acids?
Triacylglycerols (triglycerides)
60
What enzyme is responsible for fatty acid synthesis?
Megasynthase
61
What does citrate provide for fatty acid synthesis?
Acetyl-CoA
62
What pathway provides NADPH for reductive biosynthesis?
Pentose Phosphate Pathway
63
What is the first committed step of cholesterol biosynthesis?
HMG-CoA reductase
64
What do regulatory proteins in the ER control?
Gene expression of pathway enzymes based on cholesterol levels
65
What are essential amino acids?
Amino acids required from food sources as the organism cannot synthesize them
66
What are nonessential amino acids?
Amino acids that can be synthesized by the organism and are not required from the diet for survival
67
From which metabolic intermediates are amino acids synthesized?
Glycolysis and citric acid cycle
68
What role do amino acids serve in the body?
They are precursors for amine hormones and essential co-factors
69
What does nucleic acid biosynthesis combine?
Ribose from the Pentose Phosphate Pathway with amino acids
70
What is the role of ribonucleotide reductase?
Key enzyme in the dehydroxylation of nucleotide diphosphate molecules
71
What indicates the coordination of metabolic activity?
Hormone signaling
72
What is AMPK's role in metabolism?
Initiates processes that conserve cellular energy
73
What is mTOR's role in metabolism?
Promotes anabolic processes under nutrient-rich conditions
74
What can lead to diseases in the metabolic system?
Deficiencies of resources, dysfunctional enzymes/proteins, or faulty signaling
75
True or False: Metabolism is an integrated system of metabolic pathways.
True
76
What adaptation occurs when resources are deficient?
The metabolic system adapts to maintain homeostasis
77
What is a likely reason for high cholesterol returning after statin treatment?
Dysfunctional signaling or adaptation of the metabolic system
78
What is the primary function of proteins?
Proteins mediate important functions of the cell through interactions with ligands
79
What is the significance of ligand binding in protein function?
Ligand binding allows proteins to perform vital functions and have dynamic interactions
80
Define the term Kd in the context of protein binding.
Kd is the dissociation constant that measures the affinity of a ligand to a protein
81
How is the binding affinity Ka related to Kd?
Kd is the reciprocal of Ka, where higher Ka indicates greater affinity
82
What does a strong binding indicate in terms of Kd values?
Kd < 10 nM indicates strong binding
83
What does a weak binding indicate in terms of Kd values?
Kd > 10 μM indicates weak binding
84
What type of plot characterizes ligand binding?
Ligand binding is characterized by a hyperbolic plot
85
What physiological relevance do Kd values have?
Kd values represent binding affinity and are affected by ligand concentrations
86
What are the two main types of proteins involved in oxygen transport?
* Myoglobin
* Hemoglobin
87
What is the structural difference between myoglobin and hemoglobin?
Hemoglobin has a complex structure leading to a sigmoidal binding plot
88
What is cooperativity in the context of hemoglobin?
Cooperativity is the phenomenon where the binding of oxygen enhances the affinity of hemoglobin for more oxygen
89
What are allosteric modulators?
Allosteric modulators are molecules that alter protein function by binding to regulatory sites
90
What effect does carbon dioxide have on hemoglobin's affinity for oxygen?
Carbon dioxide lowers the affinity of hemoglobin for oxygen
91
How does pH affect hemoglobin's oxygen binding?
Lower pH decreases the affinity of hemoglobin for oxygen
92
What role does 2,3-bisphosphoglycerate play in hemoglobin function?
2,3-BPG lowers hemoglobin's affinity for oxygen, allowing adjustments for changes in elevation
93
What is the pH of blood in the lungs compared to tissues?
pH of blood is 7.6 in the lungs and 7.2 in tissues
94
Fill in the blank: Allosteric regulation involves the binding of a ligand to one site affecting the binding properties of another site in the same protein, known as _______.
cooperativity
95
What can allosteric modulators be classified as?
* Inhibitors
* Activators
96
What is the function of acetazolamide in treating elevation sickness?
Acetazolamide is a carbonic anhydrase inhibitor that improves elevation sickness
97
What is the relationship between small molecules and protein function?
Small molecules can bind to regulatory sites and alter protein structure and function
98
What is the significance of ligands, effectors, and allosteric modulators in cellular metabolism?
They fine-tune the functional output of proteins to adjust metabolic activity
99
What is enzyme kinetics?
The study of the rates at which enzyme-catalyzed reactions occur
## Footnote
Enzyme kinetics parameters include turnover rate and binding affinity.
100
What role do enzymes play in metabolism?
Enzymes catalyze metabolic reactions, controlling the rate of flow in metabolic pathways.
101
Name the forces that stabilize protein structure and mediate interactions between enzyme and substrate.
* Weak interactions
* Functional groups from amino acid residues
* Entropy reduction
* Desolvation
* Distortion
* Alignment of catalytic functional groups
102
What does the term 'turnover rate' refer to in enzyme kinetics?
How fast an enzyme performs a reaction.
103
What is the significance of the Michaelis-Menten equation?
It relates the rate of reaction to substrate concentration and enzyme kinetics parameters.
104
Define K_m in the context of enzyme kinetics.
K_m = (k_-1 + k_2)/k_1, represents the substrate concentration at which the reaction rate is half of V_max.
105
What is V_max?
Maximum velocity of enzyme-catalyzed reaction.
106
What does k_cat represent?
Turnover number, defined as k_cat = V_max/[E_t].
107
What is catalytic efficiency?
k_cat/K_m, allows comparison of enzyme efficiency.
108
True or False: All enzymes are regulated at the substrate level.
True.
109
What is feedback inhibition?
Products of a pathway inhibit the enzyme at the beginning of the pathway.
110
List the types of enzyme regulation.
* Allosteric regulation
* Reversible covalent modification
* Irreversible modification
* Hormonal regulation
111
What are isozymes?
Different enzymes that catalyze the same reaction but have different kinetic parameters.
112
Fill in the blank: Enzyme inhibitors are molecules that _______ with catalysis.
interfere
113
What differentiates reversible from irreversible inhibitors?
Reversible inhibitors interact non-covalently; irreversible inhibitors covalently modify the enzyme.
114
What is competitive inhibition?
Inhibitor binds to the same active site as the substrate.
115
Describe uncompetitive inhibition.
Inhibitor binds only to the ES complex at a distinct site from the substrate.
116
What is mixed inhibition?
Inhibitor binds to a distinct site from the active site, affecting either E or ES.
117
What is a suicide inhibitor?
A type of irreversible inhibitor that inactivates the enzyme through covalent modification.
118
What is the role of allosteric enzymes?
They sense chemical conditions and alter their activity accordingly.
119
What is the effect of hormone regulation on enzyme activity?
Hormones can alter gene expression and modulate enzyme activity through various mechanisms.
120
What is the Warburg Effect?
Cancer cells preferentially metabolize glucose through glycolysis rather than oxidative phosphorylation.
121
Fill in the blank: Drugs often act as _______ that alter flow through metabolic pathways.
enzyme inhibitors
122
True or False: V_max changes with competitive inhibition.
False.
123
What is the significance of the Lineweaver-Burke plot?
It helps visualize the kinetics of enzyme inhibition.
124
What is the role of effectors/modulators in enzyme regulation?
They can enhance or decrease enzyme activity through allosteric interactions.
125
What does metabolism reflect?
The functional role of tissues
## Footnote
Metabolism is closely tied to the specific functions that different tissues and cells perform in the body.
126
How do different tissues/cells carry out their roles?
Through different metabolic processes
## Footnote
The specific roles of tissues are reflected in their unique metabolic activities.
127
What produces cellular variation and metabolism?
Alternate gene expression controlled by epigenetics
## Footnote
Epigenetics plays a crucial role in determining how cells differ from one another in function and metabolism.
128
What reflects functional roles in metabolism?
Variations in fuel usage
## Footnote
Different cells may utilize different energy sources based on their specific functions.
129
What directs, guides, and coordinates metabolism?
Sensory proteins, both internal and external
## Footnote
These proteins help create an integrated metabolic system across different tissues.
130
What dictates cell function?
Metabolism
## Footnote
The metabolic processes of a cell are closely tied to its specific function in the body.
131
What is the genome?
An instruction manual for functional materials needed for cell function
## Footnote
The genome contains the genetic blueprint for proteins and RNA required for cellular activities.
132
What leads stem cells to differentiate into defined cell types?
Signaling
## Footnote
External signals influence the differentiation process of stem cells.
133
What mediates the metabolic profile of different cell/tissue types?
Proteins produced, their abundance, and specific isotypes
## Footnote
The types and amounts of proteins present in a cell are critical for its metabolic functions.
134
What is the epigenome?
Nuclear information heritable during cell division
## Footnote
The epigenome influences gene expression without altering the DNA sequence.
135
What are the components of the epigenome?
* DNA methylation
* Histone post-translational modifications
* micro/si-RNA
## Footnote
These components play a key role in regulating gene expression.
136
What does epigenetics control?
Development, tissue differentiation, and cellular responsiveness
## Footnote
Epigenetic factors determine how cells respond to various signals and develop into specific tissue types.
137
What factors control epigenetic information?
* Genome sequence
* Environmental exposure
* Stochasticity (random chance)
## Footnote
These factors can influence the epigenetic landscape without changing the underlying DNA.
138
What changes between tissues?
* Receptors that coordinate metabolism
* Transporters that enable molecule/metabolite entry
* Enzymes present
* Isozyme type present
## Footnote
These differences contribute to the unique metabolic profiles of various tissue types.
139
What is alternate gene splicing?
A process that can result in different isoenzymes/protein isoforms
## Footnote
This process allows for increased diversity in protein function from a single gene.
140
What do metabolic profiles reflect?
Proteome differences
## Footnote
The specific proteins present in a tissue can indicate its metabolic capabilities.
141
How is system-wide metabolic activity coordinated?
Through hormone signaling
## Footnote
Hormones play a key role in regulating the metabolic activities of different tissues.
142
What do cells contain to tune internal metabolism?
Internal regulators
## Footnote
These regulators work alongside external signals to adjust metabolic processes.
143
True or False: The liver is the main metabolizer of fructose.
True
## Footnote
The liver has specialized pathways for metabolizing fructose, which is important for understanding metabolic health.
144
Fill in the blank: Different tissues have different _______ based on their function.
metabolic profiles
## Footnote
This highlights the relationship between tissue function and metabolism.
