Download BIO-CHEM MODULE 4 EXAM and more Exams Biochemistry in PDF only on Docsity!
BIO-CHEM MODULE 4 EXAM QUESTIONS WITH VERIFIED ANSWERS
“where does glycolysis occur and what type of process - CORRECT ANSWER cytosol +
anaerobic"
"enzyme activators - CORRECT ANSWER ADP, AMP, Ca2+
these indicate there is low energy"
"enzyme inhibitors - CORRECT ANSWER ATP and NADH
these indicate there is high energy"
"product inhibition - CORRECT ANSWER succinylcholine-CoA, citrate"
"Citrate Synthase - CORRECT ANSWER Oxaloacetate --> Citrate"
"alpha-Ketoglutarate Dehydrogenase Complex - CORRECT ANSWER alpha-Ketoglutarate -->
Succinyl-CoA"
"pyruvate structure - CORRECT ANSWER "
"Acetyl CoA - CORRECT ANSWER Acetyl coenzyme A; the entry compound for the citric acid
cycle in cellular respiration, formed from a fragment of pyruvate attached to a coenzyme."
"step 1 intermediate - CORRECT ANSWER citrate"
"step 2 intermediate - CORRECT ANSWER isocitrate"
"step 3 intermediate - CORRECT ANSWER alpha-ketoglutarate"
"step 4 intermediate - CORRECT ANSWER succinyl-CoA"
"step 5 intermediate - CORRECT ANSWER succinate"
"step 6 intermediate - CORRECT ANSWER fumarate"
"step 7 intermediate - CORRECT ANSWER malate"
"step 8 intermediate - CORRECT ANSWER oxaloacetate"
"synthesis of compounds - CORRECT ANSWER less dG than ATP hydrolysis"
"hydrolysis of a compound - CORRECT ANSWER more dG than ATP synthesis"
"which steps in glycolysis use ATP - CORRECT ANSWER Steps 1 and 3"
"which steps in glycolysis create ATP - CORRECT ANSWER Steps 7 and 10"
"ADP structure - CORRECT ANSWER "
"aldose functional group - CORRECT ANSWER glucose"
"ketose functional group - CORRECT ANSWER fructose"
"pyranose - CORRECT ANSWER 6 membered ring"
"phosphoglycerate mutase - CORRECT ANSWER 3-phosphoglycerate to 2-phosphoglycerate
creates a moderate phosphoric transfer potential"
"enolase - CORRECT ANSWER dehydration creates very high energy unstable molecule"
"Why do scientists use the saccharide-based terms to describe carbohydrates? - CORRECT
ANSWER because the word sugar can refer to any carbohydrate molecule"
"What is a monosaccharide? - CORRECT ANSWER a simple sugar or monomeric sugar"
"Monosaccharides found in nature typically have how many carbons? - CORRECT ANSWER
three to eight carbons"
"What are the smallest monosaccharides? - CORRECT ANSWER the three-carbon trioses:
glyceraldehyde and dihydroxyacetone"
"What are Fischer projection formulas? Describe them. What is carbon-1? - CORRECT
ANSWER -named after Emil Fischer who described them, they are two-dimensional structures
that represent three-dimensional carbohydrates or other organic molecules
"What is a pyranose ring? - CORRECT ANSWER Pyranose rings have six atoms in their ring
structures. Both pyranose and furanose rings are heterocyclic since an atom other than carbon is part of the cyclic structure."
"Where does the oxygen come from in the cyclic structures? - CORRECT ANSWER The oxygen
component of the carbohydrate ring comes from an oxygen atom that began as one of the alcohol groups. This functional group reacts with another carbon in the same molecule to form a ring."
"What is a hemiacetal? - CORRECT ANSWER The molecule that forms after the oxygen from
carbon-5 and carbon-1 react to form a bond, called a hemiacetal."
"What is a Haworth projection? - CORRECT ANSWER a structural model for drawing cyclic
monosaccharides"
"What is the anomeric carbon? - CORRECT ANSWER carbon-1, products produced differ in
orientation"
"What is beta? Alpha? - CORRECT ANSWER -the beta form has the -OH in the "up" position
-the -OH is "down" in the alpha form"
"What are anomers? - CORRECT ANSWER structural forms that differ only in the -OH
orientation about the carbon that forms the hemiacetal group"
"How do you draw the Haworth projection for galactose? - CORRECT ANSWER to draw a
Haworth projection of galactose, first start with the galactose in its Fischer projection. Next, draw the pyranose form with oxygen in the upper right of the hexagon structure and -CH2OH group of carbon-6 in the up position (all D-carbohydrates have carbon-6 "up"). Next, for carbon-2, 3 and 4, orient the -OH in the up position if it is left on the Fischer projection; put the -OH in the "down" position if right. Remember, carbon-5 no longer has an -OH since its oxygen is involved in the hemiacetal bond. Last, if drawing the beta form, show the -OH "up" at carbon-1, but "down" for the alpha form."
"What is interconversion or mutarotation? - CORRECT ANSWER when anomers convert from
one ring structure to the other through the open chain molecule"
"What is the only structure found in polysaccharides? Why? - CORRECT ANSWER -the ring
form is the only structure found -this result is due to bonding that takes place at the anomeric carbon that "locks" the ring structure in place"
"What is an O-glycosidic linkage? - CORRECT ANSWER Two monosaccharides react through a
condensation reaction to form a glycosidic linkage, which is also called an O-glycosidic linkage to highlight the oxygen atom in the bond."
"What is the most common bond for hexoses to make? - CORRECT ANSWER between carbon-
of one molecule and carbon-4 of the second molecule"
"When is 1-> 6 O-glycosidic linkage common? - CORRECT ANSWER This 1→ 6 O-glycosidic
linkage is common in polysaccharides where branches form from the main chain."
"What is lactose made up of? - CORRECT ANSWER contains two different monosaccharides,
galactose and glucose, joined together by a β1→4 connection"
"What does sucrose contain? - CORRECT ANSWER the monosaccharide fructose, which exists
as a furanose ring"
"What do polysaccharides consist of? - CORRECT ANSWER large numbers of monosaccharides
joined together in long chains by O-glycosidic bonds"
"How many monosaccharides are in a polysaccharide? - CORRECT ANSWER typically one
thousand to one million monosaccharides"
"What is a homopolymers? - CORRECT ANSWER polysaccharides made up of the same
monosaccharides"
"What type of polysaccharide is glucose? - CORRECT ANSWER homopolymer"
"What is a heteropolysaccharide? - CORRECT ANSWER have two more types of
monosaccharides, often in repeating fashion, in the structure"
"What three crucial homopolysaccharides does glucose make duo? - CORRECT ANSWER
starch, glycogen, and cellulose"
"What form does plants store carbohydrates and what is it made up of? - CORRECT ANSWER
Plants store carbohydrates in the form of starch, which is made up of amylose and amylopectin."
"What is the composition of amylose? - CORRECT ANSWER Amylose is a linear chain of
glucose joined together in α1 → 4 bonds in one continuous chain with no branching. These chains have a few thousand to a million glucose molecules bonded together and referred to as the main chain."
-It possesses a linear chain of glucose molecules connected through β1 → 4 bonds. Chitin is different because it has derivatized glucose molecules in its chain. To each glucose molecule a - NH-CO-CH3 group has been added to carbon-2, which gives the chitin chain the ability to form sheets of exoskeleton."
"What is the critical bond and why? - CORRECT ANSWER Hydrogen bonds are the critical non-
covalent form due to the significant number of -OH groups on each glucose molecule."
"How does bonding occur in homopolysaccharides? - CORRECT ANSWER In
homopolysaccharides, the repeating structure permits many intra-molecular hydrogen-bonds to form, which results in the massive structure."
"How does amylose bond? - CORRECT ANSWER Amylose, for instance, forms an alpha-helix
structure similar to that of proteins. Amylose bends to adopt a conformation suitable to form a helix, permitting amylose to fold into tight bundles for storage."
"What are polysaccharides essential for? - CORRECT ANSWER energy storage and structure"
"Is the following molecule an aldose or ketose? Briefly explain. - CORRECT ANSWER ketose.
There is a C=O on the third carbon from the top." "Which carbon in erythrose would tell you if the monosaccharide is D or L? Give the carbon's
number in your answer. - CORRECT ANSWER On carbon number 3, which is the penultimate
carbon."
"Glucose and mannose are epimers. Name another epimer of glucose besides mannose. -
CORRECT ANSWER Galactose."
"Is the following structure a D or L carbohydrate? Briefly explain. - CORRECT ANSWER L. The -
OH group is on the left side on the penultimate carbon."
"Does the compound C7H14O8 fit the formal definition of a carbohydrate? Explain. - CORRECT
ANSWER No. This compound has does not fit the formula CnH2nOn as indicated in the module.
There is one additional oxygen in this compound."
"Which of the following is carbon number 3? (Indicate by the appropriate letter.) - CORRECT
ANSWER C"
"Which carbon in this molecule is the anomeric carbon? (Indicate by the appropriate letter.) -
CORRECT ANSWER A"
"Is the following a furan or pyran ring? Briefly explain. - CORRECT ANSWER furan. There are
only five atoms in the ring: one oxygen and four carbons."
"When is the α 1→6 connection typically found in carbohydrates? - CORRECT ANSWER The α
1→6 bond is found in polysaccharides when branching occurs."
"Is the following an α 1→4 or β 1→4 connection? Briefly explain. - CORRECT ANSWER This is a
β 1→4 because the molecule on the left has the oxygen in the up, or beta, position." "What are the similarities and differences between amylose and amylopectin? Explain in at least
three complete sentences. - CORRECT ANSWER Similarities: Both of are homopolysaccharides
of glucose. They each have α1 → 4 connections between glucose. They each are part of starch. Differences: Amylopectin has branching with α1→6 linkages. Amylose does not. Amylopectin is typically larger than amylose."
"How is chitin different from cellulose? - CORRECT ANSWER Chitin has glucose with
derivatives attached. -NH-CO-CH3 is connected to each glucose."
"Where are α 1 → 6 bonds found in carbohydrates? - CORRECT ANSWER They are found where
glycogen and amylopectin branch."
"In what ways are amylose and a protein alike? - CORRECT ANSWER They both can form
alpha helices."
"What is the name of the carbohydrate found in beetle exoskeleton? - CORRECT ANSWER
Chitin." If a patient is healthy and has a normal oxygen concentration in her blood, approximately how
many ATP are produced for every molecule of glucose that enters the process of metabolism? -
CORRECT ANSWER 30"
"A defect in an enzyme in the citric acid cycle causes the cycle to stop functioning. What is a
possible consequence? - CORRECT ANSWER decrease levels of ATP"
"Which best describes the role of ATP synthase? - CORRECT ANSWER ATP synthase allows
protons to flow down their concentration gradient into the matrix and generates ATP"
because NAD+ and FAD are not available in sufficient amounts; The proton gradient dissipates, resulting in a dramatic reduction in ATP production that can lead to cell death"
"What happens to glucose under anaerobic conditions? - CORRECT ANSWER Glucose
undergoes glycolysis to produce pyruvate"
"Why is the Cori Cycle important for red blood cells? - CORRECT ANSWER Red blood cells have
no mitochondria" "How many ATP are produced in the muscle cell when glucose is broken down and how many
ATP are consumed in the liver when glucose is regenerated? - CORRECT ANSWER 2 ATP are
generated when glucose is broken down in the muscle cell (through glycolysis) and 6 ATP are consumed when ATP is regenerated in the liver (through gluconeogenesis)." "True or False: Anabolic pathways result in larger molecules being made from smaller molecules
and Catabolic pathways result in larger molecules being broken down into smaller molecules. -
CORRECT ANSWER True"
"In the absence of oxygen in the exercising muscle, why does the amount of lactate in the blood
change? - CORRECT ANSWER the amount of lactate increases in the blood because lactate
produced in muscles anaerobically must travel to the liver" "Starting with one molecule of glucose, compare the amount of ATP made in aerobic vs anaerobic
respiration. - CORRECT ANSWER aerobic respiration creates 30 ATP while anaerobic
respiration creates 2 ATP"
"What is anaerobic metabolism? - CORRECT ANSWER ATP production using only substrate
level phosphorylation"
"Which molecules undergo anaerobic metabolism? - CORRECT ANSWER glucose, some amino
acids, and glycerol" "Glycolysis produces two ATP molecules. Through what process are these ATP molecules made?
CORRECT ANSWER substrate level phosphorylation"
"Which of the following differentiates aerobic from anaerobic cellular metabolism? - CORRECT
ANSWER the utilization of O2 as an electron acceptor"
"Which is incorrectly paired? - CORRECT ANSWER Lactic acid fermentation-----mitochondiral
matrix"
"Which of the following best describes the purpose of fermentation? - CORRECT ANSWER
fermentation enables the regeneration of NAD+ so that glycolysis can still occur in anaerobic conditions" "During periods of strenuous exercise, the muscle cells can become anaerobic. Without oxygen,
the ETC cannot continue and the CAC slows down. When this occurs, how do cells make ATP? -
CORRECT ANSWER Pyruvate is transformed to lactate"
"Insulin has many anabolic effects on the body. Which of the following terms best relates to
anabolic? - CORRECT ANSWER builds up"
"GluT transporters aid in glucose transport into a cell... - CORRECT ANSWER by assisting in the
transport of glucose into the cell"
"Gluconeogenesis is... - CORRECT ANSWER this process produces new glucose and is needed in
a fasting state to increase blood sugar, supplying energy to the brain and muscle"
"Glycoogenolysis is... - CORRECT ANSWER this process is the breakdown of glycogen to release
individual glucose molecules. it benefits the fasting state because it increases blood glucose"
"Where is glucagon made? - CORRECT ANSWER alpha cells of the pancreas"
"What stimulates the release of glucagon? - CORRECT ANSWER low blood glucose and a
fasting state"
"How does glucagon increase blood glucose concentration? - CORRECT ANSWER glucagon
stimulates gluconeogenesis and glycogenolysis" "There are two types of diabetes mellitus (DM) that lead to impairment in glucose utilization.
Resistance to the effects of insulin leads to which type of DM? - CORRECT ANSWER type II
diabetes" "Autoimmune destruction of beta cells in the islets of Langerhans of pancreas leads to which type
of DM? - CORRECT ANSWER type I diabetes"
"Hemoglobin A1c (sometimes referred to as A1c) is a molecule measured for a laboratory test. It is used to confirm the diagnosis of diabetes and to assess a diabetic patient's level of disease control.
How and why do advanced glycation end products (AGEs) form? - CORRECT ANSWER High
blood glucose causes glycation, a reaction where a covalent bond forms between a sugar molecule
"Which process is stimulated when insulin is released into the bloodstream? - CORRECT
ANSWER glycogenesis"
"Which of the following drives glucose from the bloodstream into cells? - CORRECT ANSWER
insulin" "Which of the following chemicals can be produced in dangerous excess in a patient taking
metformin because of its effect of decreasing the liver's participation in the Cori cycle? -
CORRECT ANSWER lactic acid"
"A 2 year old boy is found to have an autosomal recessive glycogen storage disease that prevents him from being fully able to metabolize glucose. On examination, he has an enlarged liver and bulky appearing muscles. Biopsy of both liver and muscles show markedly increased amounts of
glycogen compared to normal. Which of the following is true? - CORRECT ANSWER Since
glucose can be partially but not fully metabolized, there is an increased concentration of the intermediate compounds and this causes a shift in enzymatic reactions, favoring the production of glycogen" "Metformin treatment is able to lower blood glucose levels by ____ gluconeogenesis in the liver
cells and ____ Glut4 translocation in the muscle or fat cells. - CORRECT ANSWER decreasing,
increasing" "Insulin is a hormone that is secreted when blood glucose is _____. This hormone stimulates ____ in
the cell. - CORRECT ANSWER high, glycogenesis"
"Which of the following is stimulated by glucagon? - CORRECT ANSWER gluconeogenesis and
glycogenolysis"
"Which best describes why a patient on metformin is at risk for lactic acidosis? - CORRECT
ANSWER in the liver, metformin inhibits gluconeogenesis"
"It is 6pm. Eric skipped lunch and hasn't eaten since 7am when he left the house this morning.
Which of the following is expected? - CORRECT ANSWER Eric's body will have elevated levels
of glucagon which will trigger gluconeogenesis and glycogenolysis"
"Glucose is a monosaccharide. It can be used as the raw material to build what molecule? -
CORRECT ANSWER glycogen"
"Carbohydrate loading is a common practice among endurance athletes. Often, three days before a big endurance event, they are known to eat large amounts of complex carbohydrates which
leads to the storage of glycogen in their muscles. The stored glycogen increases their endurance
by providing a steady supply of glucose during the event by the process of ______. - CORRECT
ANSWER glycogenolysis"
"Insulin controls both carbohydrate and fat metabolism. Which of the following describes the
effects of insulin? - CORRECT ANSWER Stimulates the glucose uptake and inhibits glycogen
breakdown"
"The complications of diabetes result from accumulation of which of the following: - CORRECT
ANSWER Advanced Glycation End-products (AGEs)"
"The pancreas can regulate and maintain glucose homeostasis by secreting different hormones in response to varying blood glucose levels. The pancreas secretes insulin in response to high blood
glucose levels, whereas ______ is secreted in response to _____ glucose levels. - CORRECT
ANSWER glucagon, low"
"While treatment with metformin is beneficial for many individuals with type 2 diabetes, patients are at increased risk for lactic acidosis. What effect of metformin directly contributes to
this potential risk? - CORRECT ANSWER decreased gluconeogenesis in the liver"
"What could result in better outcomes for type 2 diabetes? - CORRECT ANSWER an increased
number of GluT4 transporters in the cell membrane" "Emma was prescribed metformin which is used to control blood glucose levels. One direct effect
of metformin is inhibition of the _____ pathway in the liver. - CORRECT ANSWER
gluconeogenesis"
"Emma has an A1c level of 7.0%. A1c is a form of _____. - CORRECT ANSWER hemoglobin"
"Disaccharides are: - CORRECT ANSWER Two sugar molecules linked by alpha or beta
linkages"
"Gluconeogenesis is: - CORRECT ANSWER creating new glucose"
"Glycogen is: - CORRECT ANSWER glucose storage molecule. a ploymer of glucose units. also
referred to as a polysaccharide"
"Glycogenesis is: - CORRECT ANSWER process to build glycogen"
"______ causes blood glucose levels to rise. ______ causes blood glucose levels to fall. - CORRECT
ANSWER glucagon, insulin"
"The release of _____ is inhibited by hypoglycemia. The release of ____ is inhibited by
hyperglycemia. - CORRECT ANSWER insulin, glucagon"
"glycolysis reactants - CORRECT ANSWER glucose, 2 NAD+, 2ADP, 2 Pi"
"glycolysis products - CORRECT ANSWER 2 pyruvate, 2 ATP, 2 NADH, 2H+, 2 h2o"
"which steps are the most exergonic in glycolysis/regulate - CORRECT ANSWER 1,3,10"
"dG is + what is favored - CORRECT ANSWER reactants"
"dG is - - CORRECT ANSWER products favored"
"net flux - CORRECT ANSWER forward rxn - reverse flux"
"reduction potential equation - CORRECT ANSWER "
"free energy change equation - CORRECT ANSWER "
"spontaneous reaction - CORRECT ANSWER standard change neg, free energy pos"
"complex I - CORRECT ANSWER NADH-ubiquinone oxidoreductase"
"coenzyme Q - CORRECT ANSWER ubiquinone"
"complex II - CORRECT ANSWER succinate dehydrogenase"
"complex III - CORRECT ANSWER cytochrome C oxidoreductase"
"Complex IV - CORRECT ANSWER cytochrome c oxidase"
"E1 enzyme and cofactors - CORRECT ANSWER -pyruvate dehydrogenase
-Thiamine pyrophosphate (TPP)"
"E2 enzyme and cofactor - CORRECT ANSWER -dihydrolipoyl transacetylase
-lipoate, coenzyme A"
"E3 enzyme and cofactor - CORRECT ANSWER -dihydrolipoyl dehydrogenase
-FAD, NAD+"
"multienzyme complex advantages - CORRECT ANSWER -short distance between catalytic
sites facilitates substrate channeling between sites -substrate channeling minimizes the occurrence of side reactions -regulation of activity in one subunit affects the entire complex's function"
"E2 complex - CORRECT ANSWER group carries acetyl group from E1 to E2 to create acetyl co-
A"
"E3 reaction - CORRECT ANSWER resulting FADH2 is oxidized by NAD+"
"Succinyl-CoA Synthetase - CORRECT ANSWER Succinyl-CoA --> Succinate"
"Malate Dehydrogenase - CORRECT ANSWER Malate --> Oxaloacetate"
"Aconitase - CORRECT ANSWER Citrate --> Isocitrate"
"Succinate Dehydrogenase - CORRECT ANSWER Succinate --> Fumarate"
"Isocitrate Dehydrogenase - CORRECT ANSWER Isocitrate --> alpha-Ketoglutarate"
"Fumarase - CORRECT ANSWER Fumarate --> Malate"
"furanose - CORRECT ANSWER 5 membered ring"
"phosphoryl transfer steps - CORRECT ANSWER 1,3"
"isomerization steps - CORRECT ANSWER 2,5,8"
"substrate level phosphorylation - CORRECT ANSWER 7,10"
"dehydration step - CORRECT ANSWER 9"
"reverse aldol condensation - CORRECT ANSWER step 4"
"redox rxn - CORRECT ANSWER 6"
"What is the chemical formula of glucose? - CORRECT ANSWER C6H12O6"
"What is the general structural pattern of glucose? - CORRECT ANSWER -CnH2nOn, it can also
be written as Cn(H2O)n to highlight the water in the molecule -due to this pattern during early experiments, we call glucose a hydrate of carbon, or a carbohydrate"
"Do all carbohydrates fit the formula? - CORRECT ANSWER no"
"What is the name for table sugar? - CORRECT ANSWER sucrose"
"What is an oligosaccharide and what is it analogous to? - CORRECT ANSWER -consists of
short chains of monosaccharides joined together -oligopeptides"
"What is a polysaccharide and what is their structure? - CORRECT ANSWER -long chains of 20
or more monosaccharides joined together -some polysaccharides form linear structures while others are highly branched"
"What are some functions of carbohydrates? - CORRECT ANSWER -used as energy source in
most organisms -serve as intermediates in metabolic pathways -play an important role in structure -serve a structural role in RNA and DNA."
"What do carbohydrates do in the pentose phosphate pathway? - CORRECT ANSWER
carbohydrate intermediates enable cells to produce NADPH, which is used to control oxygen radicals"
"What are cellulose and chitin? - CORRECT ANSWER -cellulose is the molecule that forms the
basis for cornstalks -chitin is the basis for the shells of insects"
"What are monosaccharides and what functional groups do they have? - CORRECT ANSWER -
simple carbohydrates that have the general formula of CnH2nOn, such as glucose C6H12O -these molecules have either an aldehyde functional group or a ketone functional group"
"What is an aldose? - CORRECT ANSWER monosaccharides with aldehyde groups"
"What is a ketose? - CORRECT ANSWER monosaccharides with ketone groups"
"What is an example of an aldose? A ketose? - CORRECT ANSWER -D-glyceraldehyde is an
aldose -Dihydroxyacetone is a ketose"
