Cellular Biochemistry Flashcards
1
Q
What is the primary energy source used by the body?
A
Glucose
2
Q
True or False: Glucose is the only source of energy for the body.
A
False
3
Q
What process converts glucose into energy in cells?
A
Cellular respiration
4
Q
Fill in the blank: The main hormone responsible for regulating blood glucose levels is ______.
A
Insulin
5
Q
Which macromolecule is glucose derived from?
A
Carbohydrates
6
Q
Multiple Choice: Which of the following is a benefit of using glucose as an energy source? A) High energy yield B) Low availability C) Slow metabolism D) None of the above
A
A) High energy yield
7
Q
What is the preferred energy source for the brain?
A
Glucose
8
Q
True or False: The body can store glucose in the form of glycogen.
A
True
9
Q
What happens to glucose during anaerobic respiration?
A
It is converted into lactic acid.
10
Q
Fill in the blank: When glucose levels are low, the body can produce glucose through a process called ______.
A
Gluconeogenesis
11
Q
Multiple Choice: Which of the following can also be used as an energy source besides glucose? A) Fatty acids B) Amino acids C) Ketones D) All of the above
A
D) All of the above
12
Q
What is the role of ATP in relation to glucose?
A
ATP stores and provides energy derived from glucose.
13
Q
True or False: Glucose can be used directly by all cells in the body.
A
True
14
Q
What is the significance of glucose in metabolic pathways?
A
It acts as a central metabolite in energy production.
15
Q
Fill in the blank: The breakdown of glucose to produce energy occurs in the ______.
A
Mitochondria
16
Q
Multiple Choice: What is the primary product of glycolysis? A) Pyruvate B) Acetyl-CoA C) Lactic acid D) Glucose
A
A) Pyruvate
17
Q
What is the role of glucose in homeostasis?
A
It helps maintain stable blood sugar levels.
18
Q
True or False: Glucose can be converted into fat for long-term energy storage.
A
True
19
Q
What is the term for the process by which glucose is formed from non-carbohydrate sources?
A
Gluconeogenesis
20
Q
Fill in the blank: The enzyme that breaks down glucose in glycolysis is called ______.
A
Hexokinase
21
Q
Multiple Choice: Which hormone increases blood glucose levels? A) Insulin B) Glucagon C) Somatostatin D) None of the above
A
B) Glucagon
22
Q
What is the primary function of insulin in relation to glucose?
A
To lower blood glucose levels by facilitating its uptake into cells.
23
Q
True or False: The body can use glucose for both immediate energy and storage.
A
True
24
Q
What is the consequence of prolonged high blood glucose levels?
A
It can lead to diabetes mellitus.
25
Fill in the blank: The complete oxidation of glucose in aerobic respiration yields ______ molecules of ATP.
36-38
26
Where do glycolysis reactions occur in the cell?
In the cytoplasm.
27
What is the primary location for the citric acid cycle (Krebs cycle)?
In the mitochondria.
28
True or False: The electron transport chain is located in the cytosol.
False.
29
Fill in the blank: The electron transport chain is located in the __________ of the mitochondria.
inner membrane.
30
Which cellular structure is responsible for ATP production during oxidative phosphorylation?
The mitochondria.
31
What process occurs in the chloroplasts of plant cells?
Photosynthesis.
32
True or False: Fermentation occurs in the mitochondria.
False.
33
During which process do cells convert glucose into pyruvate?
Glycolysis.
34
Where does the conversion of pyruvate to acetyl-CoA take place?
In the mitochondria.
35
Multiple choice: Which of the following reactions occurs in the cytoplasm? A) Krebs Cycle B) Glycolysis C) Electron Transport Chain
B) Glycolysis.
36
What is the main purpose of the citric acid cycle?
To produce electron carriers for the electron transport chain.
37
Where in the cell does the light-dependent reaction of photosynthesis take place?
In the thylakoid membranes of the chloroplasts.
38
True or False: The Calvin cycle occurs in the stroma of chloroplasts.
True.
39
Fill in the blank: The process of breaking down fatty acids for energy occurs in the __________.
mitochondria.
40
What is the final electron acceptor in the electron transport chain?
Oxygen.
41
Where does substrate-level phosphorylation occur?
In the cytoplasm during glycolysis and in the mitochondria during the Krebs cycle.
42
Multiple choice: Which organelle is primarily involved in aerobic respiration? A) Ribosome B) Mitochondria C) Nucleus
B) Mitochondria.
43
What is produced as a byproduct of the electron transport chain?
Water.
44
True or False: The Krebs cycle directly produces ATP.
False.
45
Where does the synthesis of ATP via ATP synthase occur?
In the inner mitochondrial membrane.
46
Fill in the blank: The process of anaerobic respiration occurs in the __________.
cytoplasm.
47
What is the main function of the mitochondria?
To generate ATP through bioenergetic reactions.
48
Where in the cell does the process of glycolysis take place?
In the cytoplasm.
49
What are the two main types of bioenergetic processes in cells?
Aerobic and anaerobic respiration.
50
True or False: ATP is produced in the stroma of chloroplasts during photosynthesis.
True.
51
Fill in the blank: The Calvin cycle uses ATP and NADPH to convert __________ into glucose.
carbon dioxide.
52
What is the definition of aerobic metabolism?
Aerobic metabolism is the process of producing cellular energy in the presence of oxygen.
53
What is the definition of anaerobic metabolism?
Anaerobic metabolism is the process of producing cellular energy without the use of oxygen.
54
Which metabolic process occurs in the mitochondria?
Aerobic metabolism occurs in the mitochondria.
55
Which metabolic process occurs in the cytoplasm?
Anaerobic metabolism occurs in the cytoplasm.
56
True or False: Aerobic metabolism produces more ATP than anaerobic metabolism.
True.
57
What is the primary energy currency produced in aerobic metabolism?
Adenosine triphosphate (ATP).
58
What is a common byproduct of anaerobic metabolism?
Lactic acid.
59
Fill in the blank: Aerobic metabolism requires __________.
oxygen.
60
Fill in the blank: Anaerobic metabolism occurs when oxygen is __________.
limited or absent.
61
What is the primary substrate used in aerobic metabolism?
Glucose, fatty acids, and amino acids.
62
What is the primary substrate used in anaerobic metabolism?
Glucose.
63
Which process is faster: aerobic or anaerobic metabolism?
Anaerobic metabolism is faster.
64
Multiple choice: Which of the following is an example of anaerobic metabolism? A) Krebs cycle B) Glycolysis C) Electron transport chain
B) Glycolysis.
65
What happens to pyruvate during anaerobic metabolism?
Pyruvate is converted into lactic acid or ethanol.
66
True or False: Aerobic metabolism can sustain energy production indefinitely.
True.
67
What type of exercise primarily uses anaerobic metabolism?
Short bursts of high-intensity exercise.
68
What type of exercise primarily uses aerobic metabolism?
Long-duration, moderate-intensity exercise.
69
Fill in the blank: The end products of aerobic metabolism are __________ and water.
carbon dioxide.
70
True or False: Anaerobic metabolism can lead to muscle fatigue.
True.
71
What is the maximum ATP yield from one glucose molecule in aerobic respiration?
Up to 38 ATP molecules.
72
What is the maximum ATP yield from one glucose molecule in anaerobic respiration?
2 ATP molecules.
73
Multiple choice: Which of the following processes is aerobic? A) Fermentation B) Oxidative phosphorylation C) Glycolysis
B) Oxidative phosphorylation.
74
What role does oxygen play in aerobic metabolism?
Oxygen acts as the final electron acceptor in the electron transport chain.
75
Fill in the blank: Anaerobic metabolism is less efficient than aerobic metabolism because it produces __________.
fewer ATP.
76
What is the primary purpose of both aerobic and anaerobic metabolism?
To produce ATP for cellular processes.
77
True or False: Both aerobic and anaerobic metabolism can occur simultaneously in the body.
True.
78
What is the primary function of the Krebs cycle?
To generate electron carriers for the electron transport chain in aerobic metabolism.
79
What is the primary purpose of glycolysis?
To convert glucose into pyruvate and produce ATP and NADH.
80
True or False: Glycolysis occurs in the mitochondria.
False. Glycolysis occurs in the cytoplasm.
81
What are the end products of glycolysis?
2 pyruvate, 2 ATP, and 2 NADH.
82
What is the first step of glycolysis?
The conversion of glucose to glucose-6-phosphate.
83
Fill in the blank: Glycolysis results in a net gain of ____ ATP.
2 ATP.
84
What is the main function of the Krebs cycle?
To oxidize acetyl-CoA to produce NADH, FADH2, and ATP.
85
How many carbon dioxide molecules are produced in one turn of the Krebs cycle?
2 carbon dioxide molecules.
86
Which molecule enters the Krebs cycle?
Acetyl-CoA.
87
True or False: The Krebs cycle occurs in the cytoplasm.
False. The Krebs cycle occurs in the mitochondrial matrix.
88
What are the main products of one turn of the Krebs cycle?
3 NADH, 1 FADH2, 1 ATP, and 2 CO2.
89
What is the electron transport chain's main function?
To transfer electrons from NADH and FADH2 to oxygen, producing ATP.
90
In which part of the cell does the electron transport chain take place?
In the inner mitochondrial membrane.
91
Fill in the blank: The final electron acceptor in the electron transport chain is ____.
Oxygen.
92
What is produced at the end of the electron transport chain?
Water and a large amount of ATP.
93
How many ATP are generated from one molecule of glucose through glycolysis, Krebs cycle, and the electron transport chain combined?
Approximately 30-32 ATP.
94
What is substrate-level phosphorylation?
The direct formation of ATP from ADP and a phosphorylated intermediate.
95
True or False: NADH and FADH2 are produced during glycolysis.
True.
96
What role does ATP synthase play in cellular respiration?
It synthesizes ATP from ADP and inorganic phosphate using the proton gradient.
97
What happens to pyruvate after glycolysis if oxygen is present?
It is converted into acetyl-CoA before entering the Krebs cycle.
98
What is the significance of the proton gradient in the electron transport chain?
It drives ATP synthesis via chemiosmosis.
99
Which enzyme catalyzes the conversion of pyruvate to acetyl-CoA?
Pyruvate dehydrogenase.
100
Fill in the blank: The Krebs cycle is also known as the ____ cycle.
Citric acid cycle or tricarboxylic acid (TCA) cycle.
101
What is the main energy currency produced during cellular respiration?
ATP.
102
How many times does the Krebs cycle turn for each molecule of glucose?
Twice.
103
What are the two main types of phosphorylation involved in ATP generation?
Substrate-level phosphorylation and oxidative phosphorylation.
104
True or False: FADH2 generates more ATP than NADH in the electron transport chain.
False. NADH generates more ATP than FADH2.
105
What is the primary storage form of glucose in animals?
Glycogen
106
True or False: Glycogen is stored mainly in the liver and muscles.
True
107
Which enzyme catalyzes the synthesis of glycogen from glucose?
Glycogen synthase
108
Fill in the blank: Glycogen breakdown is also known as __________.
Glycogenolysis
109
What is the first step in glycogenolysis?
Phosphorylation of glycogen to glucose-1-phosphate
110
Which enzyme is responsible for the release of glucose-1-phosphate from glycogen?
Glycogen phosphorylase
111
What molecule is produced when glucose-1-phosphate is converted to glucose-6-phosphate?
Glucose-6-phosphate
112
True or False: Glycogen synthase is active when dephosphorylated.
True
113
Which enzyme converts glucose-6-phosphate to free glucose?
Glucose-6-phosphatase
114
What regulatory molecule inhibits glycogen phosphorylase?
Insulin
115
Which hormone stimulates glycogen breakdown?
Glucagon
116
Fill in the blank: The enzyme __________ is responsible for branching in glycogen.
Glycogen branching enzyme
117
What is the role of UDP-glucose in glycogen synthesis?
It serves as the activated form of glucose.
118
Which pathway is activated when energy is low in the cell?
Glycogenolysis
119
True or False: Glycogen metabolism is regulated by allosteric and covalent modifications.
True
120
What is the effect of AMP on glycogen phosphorylase?
It activates glycogen phosphorylase.
121
Which enzyme is responsible for the dephosphorylation of glycogen phosphorylase?
Phosphoprotein phosphatase
122
What is the main function of glycogen synthase?
To add glucose units to the growing glycogen chain.
123
What is the significance of the branching structure of glycogen?
It increases the solubility and accessibility of glucose.
124
Which enzyme initiates glycogen synthesis?
Glycogenin
125
Fill in the blank: Glycogen breakdown occurs primarily in the __________.
Liver and muscle cells
126
Which two main processes regulate glycogen metabolism?
Glycogenesis and glycogenolysis
127
True or False: Glycogen metabolism is entirely independent of insulin.
False
128
What is the primary product of glycogenolysis?
Glucose-6-phosphate
129
Which enzyme is responsible for the removal of glucose residues from the non-reducing ends of glycogen?
Glycogen phosphorylase
130
What is the role of adrenaline in glycogen metabolism?
It stimulates glycogen breakdown during stress or exercise.
131
What is a common clinical example of a carbohydrate metabolism disorder?
Diabetes Mellitus
132
True or False: Phenylketonuria (PKU) is a disorder related to amino acid metabolism.
True
133
Fill in the blank: Galactosemia results from the inability to metabolize ______.
galactose
134
What enzyme deficiency is associated with Maple Syrup Urine Disease?
Branched-chain alpha-keto acid dehydrogenase
135
Which metabolism disorder is characterized by the accumulation of glycogen in tissues?
Glycogen storage disease
136
True or False: Urea cycle disorders affect the body's ability to detoxify ammonia.
True
137
What is the primary metabolic defect in Tay-Sachs disease?
Hexosaminidase A deficiency
138
Multiple choice: Which of the following is NOT a type of lipid metabolism disorder? A) Familial Hypercholesterolemia B) Gaucher's Disease C) Cystic Fibrosis
C) Cystic Fibrosis
139
What condition is caused by a deficiency of the enzyme lactase?
Lactose intolerance
140
Fill in the blank: Individuals with _______ have a disorder that affects the metabolism of the amino acid phenylalanine.
Phenylketonuria (PKU)
141
What is the main clinical manifestation of Maple Syrup Urine Disease?
Sweet-smelling urine
142
True or False: Wilson's disease is a disorder of copper metabolism.
True
143
What is the primary treatment for patients with phenylketonuria?
A low-phenylalanine diet
144
Multiple choice: Which of the following is a symptom of galactosemia? A) Jaundice B) Increased appetite C) Hyperactivity
A) Jaundice
145
What is the genetic basis of Cystic Fibrosis?
Mutations in the CFTR gene
146
Fill in the blank: In Pompe disease, there is a deficiency of the enzyme ______.
acid alpha-glucosidase
147
What metabolic disorder is characterized by the inability to break down very long-chain fatty acids?
Very long-chain acyl-CoA dehydrogenase deficiency
148
True or False: Mitochondrial disorders primarily affect energy production in cells.
True
149
What is a common clinical test used to diagnose metabolic disorders in newborns?
Newborn screening
150
Multiple choice: Which of the following conditions is associated with high levels of uric acid? A) Gout B) Diabetes C) Hemophilia
A) Gout
151
What is the primary clinical feature of hyperlipidemia?
Elevated lipid levels in the blood
152
Fill in the blank: The condition known as _______ is characterized by the accumulation of phenylalanine in the body.
Phenylketonuria (PKU)
153
What is a potential consequence of untreated galactosemia?
Cataracts
154
True or False: The primary treatment for Wilson's disease involves chelation therapy.
True
155
What is the hallmark symptom of hereditary fructose intolerance?
Hypoglycemia after fructose ingestion
156
What is the primary location of fatty acid oxidation in the cell?
Mitochondria
157
True or False: Fatty acid oxidation occurs in the cytoplasm.
False
158
What is the first step in the oxidation of fatty acids?
Activation of fatty acids to form acyl-CoA
159
Fill in the blank: Fatty acids are activated to acyl-CoA in the presence of _____ and ATP.
Coenzyme A
160
What enzyme catalyzes the formation of acyl-CoA from fatty acids?
Acyl-CoA synthetase
161
What must happen to acyl-CoA before it can enter the mitochondria?
It must be converted to acylcarnitine.
162
True or False: Acylcarnitine can cross the mitochondrial membrane.
True
163
What enzyme is responsible for converting acyl-CoA to acylcarnitine?
Carnitine acyltransferase I
164
What happens to acylcarnitine once it is inside the mitochondria?
It is converted back to acyl-CoA.
165
What enzyme converts acylcarnitine back to acyl-CoA inside the mitochondria?
Carnitine acyltransferase II
166
What is the main cycle involved in the oxidation of fatty acids?
Beta-oxidation
167
How many main steps are there in one cycle of beta-oxidation?
Four steps
168
What are the four main steps of beta-oxidation?
Oxidation, hydration, another oxidation, and thiolysis
169
What is produced during the first oxidation step of beta-oxidation?
FADH2
170
What is the role of FADH2 in the cell?
It is an electron carrier that donates electrons to the electron transport chain.
171
What occurs during the hydration step of beta-oxidation?
Water is added to the double bond, forming a hydroxyl group.
172
What is produced during the second oxidation step of beta-oxidation?
NADH
173
What is the final product of the thiolysis step of beta-oxidation?
Acetyl-CoA and a shortened acyl-CoA
174
How many acetyl-CoA molecules are produced from one fatty acid molecule with n carbons?
(n/2) acetyl-CoA molecules
175
What happens to the acetyl-CoA produced in fatty acid oxidation?
It enters the citric acid cycle for further energy production.
176
True or False: Fatty acid oxidation is an anabolic process.
False
177
What is the net energy yield from the complete oxidation of a saturated fatty acid?
It varies depending on the length of the fatty acid; generally, it yields multiple ATP.
178
What role do hormones play in fatty acid oxidation?
Hormones such as glucagon and epinephrine stimulate fatty acid oxidation.
179
Fill in the blank: The process of fatty acid oxidation is regulated by the availability of _____ and the energy status of the cell.
Fatty acids
180
What is the impact of insulin on fatty acid oxidation?
Insulin inhibits fatty acid oxidation.
181
What is the primary location for fatty acid oxidation in the cell?
Mitochondria
182
True or False: Fatty acid oxidation is also known as beta-oxidation.
True
183
Fill in the blank: The first step of fatty acid oxidation involves the activation of fatty acids to form __________.
fatty acyl-CoA
184
What enzyme catalyzes the conversion of fatty acids to fatty acyl-CoA?
Acyl-CoA synthetase
185
What is the role of carnitine in fatty acid oxidation?
It transports fatty acyl-CoA into the mitochondria.
186
Which enzyme facilitates the transport of fatty acyl-CoA across the mitochondrial membrane?
Carnitine acyltransferase I
187
What happens to fatty acyl-CoA once it enters the mitochondria?
It undergoes beta-oxidation.
188
In beta-oxidation, how many carbon atoms are removed in each cycle?
Two carbon atoms
189
What are the main products of one cycle of beta-oxidation?
Acetyl-CoA, NADH, and FADH2
190
True or False: Beta-oxidation occurs in the cytosol of the cell.
False
191
What molecule is produced from the complete oxidation of one fatty acid?
Multiple molecules of Acetyl-CoA
192
During beta-oxidation, what is the function of FAD?
It acts as an electron acceptor to form FADH2.
193
What role does NAD+ play in the beta-oxidation process?
It is reduced to NADH.
194
Fill in the blank: The final product of beta-oxidation is __________.
Acetyl-CoA
195
What cycle does Acetyl-CoA enter after beta-oxidation?
Citric Acid Cycle (Krebs Cycle)
196
Which energy-carrying molecules are generated during beta-oxidation?
NADH and FADH2
197
What is the significance of Acetyl-CoA in metabolism?
It is a key intermediate in energy production and biosynthesis.
198
Which type of fatty acids cannot be oxidized in the mitochondria without modification?
Unsaturated fatty acids
199
True or False: Oxidation of fatty acids provides more ATP than oxidation of glucose.
True
200
What is the total number of ATP generated from the complete oxidation of a saturated fatty acid with 16 carbons?
106 ATP
201
Fill in the blank: The process of fatty acid oxidation is regulated by __________.
Hormonal signals and energy status of the cell
202
What happens to excess Acetyl-CoA when carbohydrate availability is low?
It is converted into ketone bodies.
203
Name one condition that stimulates fatty acid oxidation.
Fasting or prolonged exercise
204
What is the end product of fatty acid oxidation that can be used for energy in various tissues?
Acetyl-CoA
205
True or False: Beta-oxidation is an anaerobic process.
False
206
What is the first step in the process of converting fatty acids into energy?
Activation of fatty acids to form fatty acyl-CoA
207
What is the primary purpose of fatty acid catabolism?
To produce ATP through the breakdown of fatty acids.
208
What is the first step in the activation of fatty acids?
Fatty acids are activated by conversion to acyl-CoA.
209
True or False: Fatty acid activation requires ATP.
True.
210
What enzyme catalyzes the conversion of fatty acids to acyl-CoA?
Acyl-CoA synthetase.
211
Fill in the blank: The conversion of fatty acids to acyl-CoA occurs in the _____ of the cell.
cytosol.
212
What is the role of carnitine in fatty acid transport?
Carnitine facilitates the transport of acyl-CoA into the mitochondria.
213
What is formed when acyl-CoA reacts with carnitine?
Acylcarnitine.
214
Which mitochondrial membrane does acylcarnitine pass through?
The inner mitochondrial membrane.
215
What enzyme is responsible for converting acylcarnitine back to acyl-CoA inside the mitochondria?
Carnitine acyltransferase II.
216
What happens to acyl-CoA after it is transported into the mitochondria?
It undergoes beta-oxidation.
217
True or False: Beta-oxidation occurs in the cytosol.
False.
218
What are the main products of beta-oxidation?
Acetyl-CoA, NADH, and FADH2.
219
What is the fate of the acetyl-CoA produced from beta-oxidation?
It enters the citric acid cycle for further energy production.
220
How many ATP are produced from each molecule of NADH generated in beta-oxidation?
2.5 ATP.
221
How many ATP are produced from each molecule of FADH2 generated in beta-oxidation?
1.5 ATP.
222
What role does the carnitine shuttle play in fatty acid metabolism?
It transports long-chain fatty acids into the mitochondria for oxidation.
223
Which enzyme catalyzes the conversion of acyl-CoA to acylcarnitine?
Carnitine acyltransferase I.
224
True or False: Fatty acids can be directly transported into the mitochondria without modification.
False.
225
What is the significance of the concentration of carnitine in the cell?
It regulates the transport of fatty acids into the mitochondria.
226
Fill in the blank: Beta-oxidation occurs in the _____ of the mitochondria.
matrix.
227
What is the end product of the complete beta-oxidation of a saturated fatty acid?
Acetyl-CoA molecules.
228
What is the energy yield from the complete oxidation of palmitic acid (C16:0)?
Approximately 106 ATP.
229
Which type of fatty acids can enter the mitochondria directly without the carnitine shuttle?
Short-chain and medium-chain fatty acids.
230
What is the role of malonyl-CoA in fatty acid metabolism?
It inhibits carnitine acyltransferase I, preventing fatty acid entry into mitochondria.
231
True or False: Fatty acids can be derived from glucose.
True.
232
What is ketogenesis?
Ketogenesis is the metabolic pathway through which ketone bodies are produced from fatty acids and ketogenic amino acids.
233
When does ketogenesis primarily occur?
Ketogenesis primarily occurs during periods of prolonged fasting, low-carbohydrate diets, or uncontrolled diabetes.
234
What is the primary organ responsible for ketogenesis?
The liver is the primary organ responsible for ketogenesis.
235
True or False: Ketogenesis occurs in the mitochondria of liver cells.
True.
236
What are the three main ketone bodies produced during ketogenesis?
The three main ketone bodies are acetoacetate, beta-hydroxybutyrate, and acetone.
237
Fill in the blank: Ketogenesis is a response to _______ availability.
glucose
238
What triggers the initiation of ketogenesis?
The depletion of carbohydrates and an increase in fatty acid oxidation trigger the initiation of ketogenesis.
239
What is the first step in the ketogenesis pathway?
The first step is the conversion of acetyl-CoA to acetoacetate.
240
Which enzyme catalyzes the conversion of HMG-CoA to acetoacetate?
HMG-CoA lyase catalyzes the conversion of HMG-CoA to acetoacetate.
241
What is the role of acetoacetate in the body?
Acetoacetate serves as an energy source for peripheral tissues, especially during fasting.
242
True or False: Beta-hydroxybutyrate is a ketone body that can be converted back to acetoacetate.
True.
243
What happens to excess acetyl-CoA when glucose levels are low?
Excess acetyl-CoA is converted into ketone bodies instead of entering the citric acid cycle.
244
Which hormone stimulates ketogenesis?
Glucagon stimulates ketogenesis.
245
What is the significance of ketone bodies for the brain?
Ketone bodies provide an alternative energy source for the brain during periods of low glucose availability.
246
Fill in the blank: Ketogenesis is important for maintaining _______ balance during starvation.
energy
247
Which metabolic state favors ketogenesis: fed or fasted?
Fasted.
248
What is the effect of insulin on ketogenesis?
Insulin inhibits ketogenesis.
249
What is the final product of ketogenesis that is exhaled?
Acetone is the final product of ketogenesis that is exhaled.
250
True or False: Ketogenesis can occur in muscle tissue.
False.
251
What are the potential consequences of excessive ketone production?
Excessive ketone production can lead to ketoacidosis.
252
Which enzyme is responsible for converting acetoacetate to beta-hydroxybutyrate?
Beta-hydroxybutyrate dehydrogenase is responsible for this conversion.
253
What is the primary source of fatty acids for ketogenesis during fasting?
Adipose tissue provides the primary source of fatty acids for ketogenesis.
254
Fill in the blank: Ketogenesis is a vital metabolic pathway during _______ states.
starvation
255
What is the relationship between ketogenesis and gluconeogenesis?
Ketogenesis and gluconeogenesis are both activated during fasting, but they use different substrates.
256
Which intermediate is formed from acetoacetate before being converted to beta-hydroxybutyrate?
Acetoacetyl-CoA is formed from acetoacetate before being converted to beta-hydroxybutyrate.
257
What is the main regulatory step of ketogenesis?
The main regulatory step is the conversion of acetyl-CoA to acetoacetyl-CoA by the enzyme thiolase.
258
What is the primary nitrogen removal mechanism in humans?
Deamination
259
True or False: Transamination is a mechanism that transfers nitrogen from one amino acid to another.
True
260
Fill in the blank: The process of __________ involves the removal of an amino group from an amino acid.
Deamination
261
What enzyme is primarily involved in deamination?
Glutamate dehydrogenase
262
Which amino acid is most commonly involved in transamination reactions?
Glutamate
263
Multiple Choice: Which of the following is NOT a nitrogen removal mechanism? A) Deamination B) Transamination C) Hydrolysis D) Ureagenesis
C) Hydrolysis
264
What byproduct is produced during deamination?
Ammonia
265
True or False: Urea cycle is a mechanism for nitrogen removal.
True
266
What is the main function of the urea cycle?
To convert ammonia into urea for excretion.
267
Fill in the blank: The urea cycle primarily occurs in the __________.
Liver
268
What are the two main types of reactions involved in nitrogen removal?
Deamination and transamination
269
Multiple Choice: Which of the following is a product of the urea cycle? A) Ammonia B) Urea C) Uric acid D) Creatinine
B) Urea
270
What role do amino transferases play in transamination?
They catalyze the transfer of amino groups between amino acids.
271
True or False: Transamination can lead to the formation of non-essential amino acids.
True
272
What is the significance of the urea cycle in nitrogen metabolism?
It helps detoxify ammonia produced from amino acid metabolism.
273
Fill in the blank: The enzyme __________ catalyzes the first step of the urea cycle.
Carbamoyl phosphate synthetase
274
Which amino acid can be directly deaminated to produce ammonia?
Glutamate
275
What is the end product of the urea cycle that is excreted by the kidneys?
Urea
276
Multiple Choice: Which of the following statements about deamination is true? A) It only occurs in the liver B) It produces ammonia C) It is a reversible process D) It requires oxygen
B) It produces ammonia
277
What happens to ammonia produced from deamination?
It is converted to urea in the liver.
278
True or False: Transamination reactions require a coenzyme.
True
279
What coenzyme is commonly used in transamination reactions?
Pyridoxal phosphate (PLP)
280
Fill in the blank: The conversion of __________ to urea occurs in the mitochondria and cytosol of liver cells.
Ammonia
281
What is the primary nitrogenous waste product in humans?
Urea
282
Multiple Choice: Which of the following is a key intermediate in the urea cycle? A) Citrulline B) Glutamate C) Aspartate D) All of the above
D) All of the above
283
What is the primary function of the urea cycle?
To convert ammonia into urea for excretion.
284
Where does the urea cycle primarily occur in the body?
In the liver.
285
What is the first step of the urea cycle?
Ammonia combines with bicarbonate to form carbamoyl phosphate.
286
Which enzyme catalyzes the formation of carbamoyl phosphate?
Carbamoyl phosphate synthetase I.
287
True or False: The urea cycle requires ATP.
True.
288
What molecule is formed when carbamoyl phosphate enters the urea cycle?
Citrulline.
289
Which enzyme converts citrulline into argininosuccinate?
Argininosuccinate synthetase.
290
Fill in the blank: Argininosuccinate is split into ________ and ________ by the enzyme argininosuccinate lyase.
arginine, fumarate.
291
What is the final product of the urea cycle?
Urea.
292
Which enzyme catalyzes the conversion of arginine to urea?
Arginase.
293
What is the role of fumarate in the urea cycle?
It can enter the citric acid cycle for energy production.
294
True or False: The urea cycle is regulated primarily at the step catalyzed by carbamoyl phosphate synthetase I.
True.
295
What is the key regulator of carbamoyl phosphate synthetase I?
N-acetylglutamate.
296
Which two amino acids are involved in the urea cycle?
Arginine and ornithine.
297
Fill in the blank: The urea cycle converts ________ to ________.
ammonia, urea.
298
What happens to the fumarate produced in the urea cycle?
It can be converted to malate and enter the citric acid cycle.
299
Which enzyme is responsible for the conversion of malate to oxaloacetate?
Malate dehydrogenase.
300
True or False: The urea cycle is an anabolic process.
False; it is a catabolic process.
301
What is the significance of the urea cycle in nitrogen metabolism?
It detoxifies ammonia, preventing toxic buildup in the body.
302
How many ATP equivalents are consumed in the urea cycle?
Four ATP equivalents.
303
What is the role of ornithine in the urea cycle?
It acts as a carrier molecule and is regenerated in the cycle.
304
Fill in the blank: The urea cycle is also known as the ________ cycle.
ornithine.
305
Which metabolic pathway is interconnected with the urea cycle?
The citric acid cycle.
306
What is the fate of excess urea in the body?
It is excreted in urine.
307
True or False: The urea cycle operates in the mitochondria.
True; some steps occur in the mitochondria, while others occur in the cytosol.
308
What are glucogenic amino acids?
Amino acids that can be converted into glucose through gluconeogenesis.
309
What are ketogenic amino acids?
Amino acids that can be converted into ketone bodies.
310
Name one example of a glucogenic amino acid.
Alanine.
311
Name one example of a ketogenic amino acid.
Leucine.
312
True or False: All amino acids are either glucogenic or ketogenic.
False.
313
Which amino acid is both glucogenic and ketogenic?
Isoleucine.
314
Fill in the blank: __________ amino acids can be converted into glucose.
Glucogenic.
315
Fill in the blank: __________ amino acids can be converted into ketone bodies.
Ketogenic.
316
What metabolic pathway do glucogenic amino acids primarily enter?
Gluconeogenesis.
317
What metabolic pathway do ketogenic amino acids primarily enter?
Ketogenesis.
318
List two glucogenic amino acids.
Glutamine and Aspartate.
319
List two ketogenic amino acids.
Lysine and Tryptophan.
320
True or False: Methionine is a glucogenic amino acid.
True.
321
What is the primary function of glucogenic amino acids in the body?
To provide energy by being converted to glucose.
322
What is the primary function of ketogenic amino acids in the body?
To provide energy by being converted to ketone bodies.
323
Multiple Choice: Which of the following is a glucogenic amino acid? A) Leucine B) Serine C) Lysine
B) Serine.
324
Multiple Choice: Which of the following is a ketogenic amino acid? A) Glutamate B) Phenylalanine C) Arginine
B) Phenylalanine.
325
Fill in the blank: Glucogenic amino acids can be converted to __________ or other intermediates of the citric acid cycle.
Glucose.
326
Fill in the blank: Ketogenic amino acids are converted into __________ bodies.
Ketone.
327
True or False: Glucogenic amino acids can only produce glucose.
False.
328
True or False: Ketogenic amino acids can lead to the production of glucose.
False.
329
What role do ketogenic amino acids play during fasting?
They provide an alternative energy source through ketone bodies.
330
What role do glucogenic amino acids play during starvation?
They help maintain blood glucose levels.
331
What is the significance of knowing whether an amino acid is glucogenic or ketogenic?
It helps in understanding its role in metabolism and energy production.
332
What happens to excess glucogenic amino acids in the body?
They are converted to glucose and stored as glycogen.
333
What happens to excess ketogenic amino acids in the body?
They are converted to ketone bodies and used for energy.
334
What are amino acids?
Amino acids are organic compounds that serve as the building blocks of proteins.
335
What are the two main sources of amino acids for animals?
The two main sources are dietary proteins and the breakdown of body proteins.
336
True or False: Animals can synthesize all amino acids they need.
False: Animals cannot synthesize certain amino acids, known as essential amino acids.
337
What are essential amino acids?
Essential amino acids are amino acids that must be obtained from the diet because the body cannot synthesize them.
338
Name one essential amino acid.
Examples include lysine, methionine, and tryptophan.
339
What is the primary dietary source of amino acids for carnivorous animals?
Carnivorous animals primarily obtain amino acids from consuming other animals.
340
Fill in the blank: Nitrogen balance is a measure of the difference between nitrogen ______ and nitrogen ______.
intake; excretion
341
What does a positive nitrogen balance indicate?
A positive nitrogen balance indicates that nitrogen intake exceeds nitrogen excretion, often seen in growth or recovery.
342
What does a negative nitrogen balance indicate?
A negative nitrogen balance indicates that nitrogen excretion exceeds nitrogen intake, often seen in malnutrition or illness.
343
True or False: Nitrogen is a key component of amino acids.
True: Nitrogen is a critical element in the structure of amino acids.
344
How do herbivorous animals primarily obtain amino acids?
Herbivorous animals primarily obtain amino acids from plant proteins.
345
What role do microorganisms play in amino acid availability for ruminants?
Microorganisms in the rumen help break down plant materials and synthesize amino acids.
346
What is the term for the process of breaking down proteins into amino acids?
The process is called protein catabolism.
347
Fill in the blank: The body can convert excess amino acids into ______ for energy.
glucose
348
What are non-essential amino acids?
Non-essential amino acids are amino acids that the body can synthesize on its own.
349
Name one non-essential amino acid.
Examples include alanine, aspartate, and glutamate.
350
What is the impact of inadequate protein intake on nitrogen balance?
Inadequate protein intake can lead to a negative nitrogen balance.
351
True or False: Nitrogen balance is only relevant for athletes.
False: Nitrogen balance is relevant for all individuals, including those in recovery or with dietary restrictions.
352
What happens to excess nitrogen in the body?
Excess nitrogen is excreted, primarily through urea in urine.
353
What is the significance of amino acids in metabolic processes?
Amino acids are critical for protein synthesis, enzyme function, and various metabolic pathways.
354
Describe the relationship between amino acids and hormones.
Some amino acids serve as precursors for hormone synthesis, influencing various physiological processes.
355
What dietary factors can affect nitrogen balance?
Factors include the quality and quantity of protein intake and overall caloric intake.
356
Fill in the blank: An athlete in training may require a ______ nitrogen balance to support muscle growth.
positive
357
How does aging affect amino acid metabolism?
Aging can reduce protein synthesis and alter amino acid metabolism, potentially affecting nitrogen balance.
358
What is the primary method for assessing nitrogen balance in individuals?
The primary method is measuring nitrogen intake through diet and nitrogen excretion through urine.
359
What are essential amino acids?
Amino acids that cannot be synthesized by the body and must be obtained from the diet.
360
List the nine essential amino acids.
Histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
361
True or False: Nonessential amino acids must be consumed in the diet.
False.
362
What are nonessential amino acids?
Amino acids that can be synthesized by the body and do not need to be obtained from the diet.
363
Fill in the blank: The essential amino acid _____ is important for protein synthesis and hormone production.
lysine
364
Which essential amino acid is a precursor to serotonin?
Tryptophan.
365
What is the primary metabolic source of nonessential amino acids?
The body can synthesize them from other amino acids or metabolic intermediates.
366
True or False: Arginine is considered an essential amino acid for infants.
True.
367
Which nonessential amino acid is synthesized from glutamic acid?
Glutamine.
368
Name one essential amino acid that is also a branched-chain amino acid.
Leucine.
369
What role does methionine play in amino acid metabolism?
It serves as a methyl donor in various biochemical reactions.
370
Multiple Choice: Which of the following is NOT an essential amino acid? A) Valine B) Glycine C) Threonine
B) Glycine.
371
What is phenylalanine converted into in the body?
Tyrosine.
372
Fill in the blank: The amino acid _____ can be synthesized from aspartate and is involved in the urea cycle.
arginine
373
Which essential amino acid is critical for collagen production?
Proline.
374
True or False: All amino acids are required in equal amounts for protein synthesis.
False.
375
What is the conditionally essential amino acid that becomes essential during periods of stress?
Arginine.
376
Which nonessential amino acid is synthesized from phenylalanine?
Tyrosine.
377
Multiple Choice: Which amino acid is a precursor for nitric oxide? A) Arginine B) Lysine C) Serine
A) Arginine.
378
What is the function of serine in metabolism?
It is involved in the synthesis of proteins and phospholipids.
379
List two nonessential amino acids.
Alanine and aspartate.
380
True or False: Histidine can be synthesized by the human body.
False.
381
What amino acid is important for the synthesis of neurotransmitters?
Tyrosine.
382
What is the relationship between essential amino acids and dietary protein sources?
Dietary protein sources must provide all essential amino acids for optimal health.
383
Which essential amino acid is involved in the synthesis of hemoglobin?
Histidine.
384
Fill in the blank: The amino acid _____ is important for muscle metabolism and energy production.
valine
