BIO CHEM II Flashcards
The overall chemical reaction of aerobic respiration is:
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy
Please analyze this reaction carefully, and choose the description which describes it best.
This is a reduction, because oxygen is reduced to water.
This is an oxidation, because glucose is oxidized to carbon dioxide.
This is a redox reaction, wherein oxygen is the electron acceptor and carbon and hydrogen atoms are the electron donors.
This is oxidation, because oxygen atom can be found in at least one of the reactant molecules.
This is a redox reaction, wherein oxygen is the electron acceptor and carbon and hydrogen atoms are the electron donors.
Fill in the blank. Glycolysis produces ATP via _____ .
Substrate level phosphorylation
Redox reaction
Oxidation
Isomerization
Isomerization
Fill in the blank. Triglycerides ______ chiral carbon atoms.
Always have 1
Always have 2
Always have 3
Do not always have
Do not always have
You are a scientist and you want to set up a protein phosphorylation reaction using PKA. You purchased PKA from a biotech company, and the datasheet tells you that PKA requires ATP, cAMP and Mg2+. What could be the role of these reaction mixture ingredients?
ATP and cAMP are coenzymes; Mg2+is a cofactor.
ATP is a substrate; cAMP and Mg2+ are cofactors.
ATP, cAMP, and Mg2+ are cofactors.
ATP is a substrate; cAMP is a coenzyme, and Mg2+ is a cofactor.
ATP is a substrate; cAMP is a coenzyme, and Mg2+ is a cofactor.
You are a scientist and you would like to set up a carbon fixation reaction in the test tube. You would like to make glyceraldehyde-3-phosphate [G3P] from carbon dioxide; you would like to mirror the Calvin-Benson cycle. What should you consider, when you design your experiment?
This will be an exergonic reaction, which will produce ATP and other possible high-energy molecules as well.
This will be an exergonic reaction; thus, cooling will be necessary if you would like to avoid the high-energy G3P-driven explosion.
This will be an endergonic reaction; thus, you will need an enzyme to catalyze it.
This will be an endergonic reaction; thus, you will need high energy compounds that can provide the energy, which will be stored in G3P.
This will be an endergonic reaction; thus, you will need high energy compounds that can provide the energy, which will be stored in G3P.
Fill in the blank. Bile acids emulsify_____ and expose them for _______ in the small intestine.
Cholesterol, the pancreatic hydrolase
Chylomicrons, apolipoprotein B-100
LDL, LDL receptor
Triglycerides, the pancreatic lipase
Triglycerides, the pancreatic lipase
Fill in the blank. Bile acid can emulsify fats, because it is _____.
Hydrophilic
Amphipathic
Lipophilic
Hydrophobic
Amphipathic
Fill in the blank. Triglycerides combine with bile to form _____________ and enter the central lacteal of the villi.
Low density lipoproteins
High density lipoproteins
Chylomicrons
Very low density lipoproteins
Chylomicrons
β-oxidation breaks down fatty acids to acetyl-CoA, but odd-numbered fatty acids cannot be fully converted into acetyl-CoA. How are odd-numbered fatty acids metabolized?
Odd-numbered fatty acids contribute to the regulation of the Szent-Györgyi-Krebs cycle’s intermediates through giving rise to succinyl-CoA.
Odd-numbered fatty acids do not occur naturally, and there is no metabolic pathway to break them down fully. If industrially produced odd-numbered fatty acids are consumed, then the last three carbon atoms will be excreted as a waste in the form of propionic acid.
Eukaryotic cells cannot break down the last three carbon atoms containing propionyl-CoA, but bacteria in the gastrointestinal tract can. Bacteria will produce methane gas from propionyl-CoA, and this will result in gastrointestinal discomfort.
β-oxidation breaks down fatty acids to acetyl-CoA and propionyl-CoA. Both acetyl-CoA and propionyl-CoA can step into the Szent-Györgyi-Krebs cycle, and they can be used to generate NADH and FADH2 for the electron transport chain.
Odd-numbered fatty acids contribute to the regulation of the Szent-Györgyi-Krebs cycle’s intermediates through giving rise to succinyl-CoA.
What is the contribution of fatty acids metabolism to the production of metabolites for biosynthesis and to energy production?
Metabolites for biosynthesis are produced by fatty acid catabolism; only anabolism makes energy.
Metabolites for biosynthesis are produced by fatty acid anabolism; only catabolism makes energy.
Metabolites for biosynthesis are produced by fatty acid catabolism and anabolism; only catabolism makes energy.
Metabolites for biosynthesis are produced by fatty acid catabolism; both anabolism and catabolism make energy.
Metabolites for biosynthesis are produced by fatty acid catabolism and anabolism; only catabolism makes energy.
Fill in the blank. The synthesis of__________ is the first step of fatty acid synthesis; this metabolite inhibits carnitine palmitoyltransferase, which controls fatty acid oxidation.
Malonyl-CoA
Acetyl-CoA
Citric acid
Succinyl-CoA
Malonyl-CoA
Fill in the blanks. ___________ the end product of β-oxidation, which contributes to ___________ in the first step of the Szent-Györgyi-Krebs cycle. An increased level of the latter activates fatty acid synthesis through the activation of acetyl-CoA carboxylase.
Carbon dioxide is, NADH and FADH2
Acetyl-CoA is, oxaloacetic acid
Acetyl-CoA is, citric acid
Acetyl-CoA and glycerol are, ATP
Acetyl-CoA is, citric acid
Fill in the blank. Both fatty acid synthesis and catabolism takes place through a series of ___________ reactions.
Elimination
Dehydration synthesis
Substitution
Redox
Redox
Medium chain acyl-CoA dehydrogenase (MCAD) deficiency affects 1 in 17000 people in the United States. Why should MCAD deficient people avoid prolonged fasting?
High glucagon level during fasting activates fatty acid oxidation, which cannot be completed due to MCAD deficiency. Fatty acids will be increasingly retained in the adipose tissue, and this will result in obesity.
High glucagon levels during fasting activate fatty acid oxidation, which in turn inhibits glucose oxidation. If glucose oxidation cannot be inhibited as the result of MCAD deficiency, then the brain will not get sufficient glucose.
This is a common misconception. MCAD deficient people are simple lucky, because they can eat fatty food. Most of the consumed fat is excreted in the form of medium chain fatty acids, and their adipose tissue cannot accumulate in excess.
MCAD deficient people do not have efficient fatty acid catabolism in their brain, because most of the fat energy is lost during the excretion of medium chain fatty acids.
High glucagon levels during fasting activate fatty acid oxidation, which in turn inhibits glucose oxidation. If glucose oxidation cannot be inhibited as the result of MCAD deficiency, then the brain will not get sufficient glucose.
Fill in the blank. Linoleic acid and linolenic acid cannot be synthesized in human tissues, because ____________.
Human cells can synthesize only mono-unsaturated fatty acids.
Humans are diploid organisms; only polyploid organisms have enough genes for the biosynthesis of theses fatty acids.
The corresponding biosynthetic pathway was lost during evolution.
Human cells cannot synthesize unsaturated fatty acids.
The corresponding biosynthetic pathway was lost during evolution.
Why can termites digest cellulose?
Their digestive tract secretes β-glucosidase.
Bacteria in their digestive tract secrete β-glucosidase
Their digestive tract secretes α-glucosidase.
Bacteria in their digestive tract secrete α-glucosidase.
Bacteria in their digestive tract secrete β-glucosidase
Which enzyme is a key regulator of glycolysis?
Hexokinase
Glucose 6-phosphate
Phosphofructokinase
Pyruvate kinase
Glucose 6-phosphate
Fill in the blank. ATP is required for the activity of phosphofructokinase, but high ATP level inhibits its activity. This is because ATP _____________.
Is both a substrate and an allosteric inhibitor of phosphofructokinase
Is both an allosteric activator and an allosteric inhibitor of phosphofructokinase
Is used only when there is plenty in the cell
Level decreases immediately in the presence of phosphofructokinase
Is used only when there is plenty in the cell
Fill in the blank. Both ATP and citric acid are allosteric inhibitors of the phosphofructokinase enzyme. High levels of these compounds indicate that ________________.
The cellular respiration is not going on efficiently, but the ATP level is sufficient
The cellular respiration is efficiently going on, and it is producing sufficient ATP
Phosphofructokinase expression is inhibited by ATP and citric acid
Phosphofructokinase is a subject of negative feedback inhibition as the first enzyme of the glycolytic pathway
The cellular respiration is not going on efficiently, but the ATP level is sufficient
Fill in the blank. Fermentation recycles ______, thus glycolysis can produce more ATP.
FADH2
NADP+
NAD+
AMP
NAD+
What is the final electron acceptor during fermentation?
A coenzyme
NADH
ATP
An organic molecule
An organic molecule
Fill in the blanks. Louis Pasteur, a French chemist, was the first to determine that the presence of some microorganism results in ____fermentation, while other microorganisms produce _____.
Alcoholic, acid
Acidic, carbon dioxide
Alcoholic, carbon dioxide
Ethanol, lactic acid
Alcoholic, acid
Fill in the blanks. The cyclic and the linear light reactions produce ATP, but only the ______ light reaction makes _______.
Cyclic, NADH
Cyclic, NADPH
Linear, NADPH
Linear, NADH
Linear, NADPH
Fill in the blank. A eukaryotic cell that has insufficient amount of oxaloacetate _____.
Will complete the cellular respiration of glucose to carbon dioxide, because the involved pathways do not produce net oxaloacetate.
Will not be able to survive, because it cannot complete cellular respiration.
Will produce two ATP molecules per glucose, and it will recycle NAD+ with fermentation.
Will have increased carbon dioxide binding, thus it will be able to perform carbon fixation more efficiently.
Will produce two ATP molecules per glucose, and it will recycle NAD+ with fermentation.
