Organic BioChemistry Exam 3 (University of Michigan BC 212)

MEMORIZE

What is stage two of catabolism?

breakdown of subunits into an oxidized form (acetyl-SCoA)

MEMORIZE

What is stage three of catabolism?

Acetyl-SCoA oxidized to produced CO2 & reduced Coenzymes

MEMORIZE

energy requirements for life

- energy must be released from food gradually

- energy must be stored in a readily accessible forms

- release of energy from storage must be finely controlled so that it is available exactly when and where it is needed

- just enough energy must be released to maintain body temperature

- energy in a form other than heat must be available to drive chemical reactions that are not favorable at body temperatures.

MEMORIZE

What is stage one of catabolism?

digestion of macro-molecules into subunits

MEMORIZE

What is stage four of catabolism?

oxidative phosphorylation to produce ATP & H2O

Which stage of catabolism oxidizes carbons of Acetyl-CoA to CO2 and reduces coenzymes.

stage 3

What is an Exergonic Process?

Reactions that give OFF energy. Occurs spontaneously (Delta G is a negative value.

What is an Endergonic process?

Reactions require energy to occur. occurs NONspontaneously (delta g is a positive value)

What are the four rules of a metabolic pathway?

1, metabolic pathways are highly exergonic and irreversible

2, every metabolic pathway has a committed step

3, all metabolic pathways are regulated

4, metabolic pathways in eukaryotic cells occur in specific cellular locations

True or False?

Different pathways are required to reverse highly exergonic pathways

true

True or False?

Pathways occur in separate locations in the cell so they can be more tightly regulated.

true

What type of metabolic pathway is this description: pathway follows a linear progression of reactions

linear sequence

Which is not a result of cellular respiration?

- carbon dioxide

- oxygen

- chemical energy

- heat

oxygen

True or False?

Energy storage and release is tightly controlled

True

What is this definition: All Chemical reactions that place in an organism?

metabolism

What is this definition: Processes that breakdown food (lipids carbohydrates and proteins to produce energy)

catabolism

What is this definition: Processes that require energy to build large molecules from small ones

anabolism

What type of metabolic pathway is this description: pathway regenerates initial substrate in last reaction

cyclic sequence

What type of metabolic pathway is this description: one enzyme or group of enzymes breakdown a polymer one monomer at a time/

Spiral Sequence.

Which type of metabolic pathway uses its final product as a substate for its first reduction?

- linear

- cyclic

- spiral

- none of the above

cyclic sequence

True or False

Catabolic pathways that your body uses to breakdown food all produce acetyl-CoA at the end of their catabolic stage 2

True

MEMORIZE

What is this definition? Metabolic processes produce and use high energy molecules

High Energy Molecules

MEMORIZE

What are the high energy molecules?

- Coenzymes

Acetyl-SCoA

NADH

FADH2

- ATP

REVIEW

what is this definition: an organic compound required for catalysis

coenzyme

What are Acetyl CoA: Coenzyme, Function, and vitamin name?

COENZYME: Coenzyme A

FUNCTION: carrier of acetyl groups (2 carbon groups into TCA cycle)

VITAMIN NAME: Pantothenic Acid (B5)

Which of the following molecules is considered a high energy molecule?

- NAD+

- CoA

- FAD

- Acetyl-CoA

AMP

Acetyl-CoA

What are NADH/NADPH: coenzymes, vitamin name, and function

- COENZYMES: nicotinamide adenine dinucleotide

NAD+/NADH

NADP+/NADPH

- VITAMIN: niacin (b3)

- FUNCTION: redox reactions

What are FADH2: coenzymes, vitamin name, and function

- COENZYMES: FAD/FADH2 (flavin adenine dinucleotide)

- VITAMIN: riboflavin (B2)

- FUNCTION: redox reactions

FAD is the ________ form of the coenzyme derived from riboflavin

- reduced, low energy

- oxidized, high energy

- reduced, high energy

- oxidized, low energy

oxidized, low energy

MEMORIZE:

What is reaction formula for tap hydrolysis and the delta g value?

Reaction Formula:

ATP + H2O --> ADP + HOPO3 (-2 charge) + H+

Delta G value

-7.3 Kcal/mol

What are the exergonic and endergonic reactions derived from ATP

Exergonic reactions:

ATP -> ADP (delta g = -7.3kcal/mol)

ATP -> AMP (delta g = -14.6kcal/mol)

Endergonic Reaction:

ADP -> ATP (delta g = +7.3 kcal/mol)

What and Why is ATP a good energy source?

1, ATP hydrolysis produces a medium amount of energy

2, Stable at PH 7.0

3, Requires an enemy for hydrolysis

4, Easy bond to cleave

5, Precursor for other high energy molecules

6, Universal energy in that it works in all cells

True or False

ATP can be regenerated from AMP?

false

A+B -> C+D Delta G = -3.5

E+D -> B+F Delta G = 7.0

-------------------------------

A+E -> C+F Delta G = 4.0

Which of the following statements is concerning the above chemical equation is correct?

- the above coupled reaction will occur spontaneously

- the above coupled reaction will not occur spontaneously

- the endergonic portion of the reaction has a delta g = -3.5

- the exergonic portion of the reaction has a delta g = 7.5

the above coupled reaction will not occur spontaneously

MEMORIZE:

Classification of Carbohydrates - What is the answer matching this definition?

A member of a large class of naturally occurring polyhyrdoxy ketones and aldehydes

carbohydrates

MEMORIZE:

Classification of Carbohydrates - What is the answer matching this definition?

A carbohydrate that cannot e chemically broken down into a smaller sugar by hydrolysis with aqueous acids. Composed of 3-7 carbons. (simple sugar)

monosaccharide

MEMORIZE:

Classification of Carbohydrates - What is the answer matching this definition?

A carbohydrate composed of two monosaccharides

disaccharide

MEMORIZE:

Classification of Carbohydrates - What is the answer matching this definition?

A carbohydrate which is a polymer of monosaccharides (complex carbohydrate)

polysaccharide

MEMORIZE:

Classification of Carbohydrates - What is the answer matching this definition?

A monosaccharide that contains an aldehyde group

Aldose

MEMORIZE:

Classification of Carbohydrates - What is the answer matching this definition?

A monosaccharide that contains a ketone group

ketose

What is the suffix that all carbohydrates end in?

-ose

An Aldose is a carbohydrate that ___________?

- begins with a ketone group and ends with an alcohol group

- begins with an aldehyde group followed by chiral carbons bounds to alcohol groups

- begins with an aldehyde group and ends with an alcohol group

begins with an ketone group followed by charcoal carbons bound to alcohol groups

begins with an aldehyde group and ends with an alcohol group

MEMORIZE

Isomers of Carbohydrates - what is the answer matching this definition?

- monosaccharides that are mirror images of one another

- d form of all monosaccharides is the most prevalent form in nature

D & L isomers (Enantiomers)

MEMORIZE

Isomers of Carbohydrates - what is the answer matching this definition?

- Monosaccharides that are stereoisomers but not mirror images of one another. (ie. monosaccharides that have the same number of carbons but have different configurations of the hydroxyl and carbonyl groups about those carbon atoms)

diastereomers

MEMORIZE

Isomers of Carbohydrates - what is the answer matching this definition?

- A monosaccharide has alpha and beta isomers that occur in different ratios in nature. The beta form of glucose is the most prevalent in nature

Anomers

What is a chiral carbon?

Carbon atom bonded to 4 different atoms or groups of atoms

What is the difference between D & L isomers

In a monosaccharide with the -OH group on the chiral atom farthest from the carbonyl group (If it is D it is pointing to the right in the Fischer Projection) (If it is L it is pointing to the left in the Fischer Projection)

True or False

A carbohydrate is an L-isomer, if in its Fischer projection, the -OH group is positioned on the left side of the first chiral carbon

False

Which of the following statements is true?

- if the -OH group bound the anomeric carbon is located below the ring structure of the monosaccharide, then the saccharide is in the beta configuration.

- if the -OH group bound to the anomeric carbon is located below the ring structure of the monosaccharide, then the saccharide is in the alpha configuration.

- the hemiacetal conformation of a saccharide is unstable

- none of the above statements is true

- if the -OH group bound to the anomeric carbon is located below the ring structure of the monosaccharide, then the saccharide is in the alpha configuration.

What type of reaction of carbohydrates is the following definition?

Carbohydrates that react with oxidizing agents are called reducing sugars as they cause other chemicals to be reduced

oxidation

What type of reaction of carbohydrates is the following definition?

monosaccharides are cyclic hemiacetals that react with alcohols to form acetals (compounds with 2 -OR groups). this occurs in the formation of glycosides, disaccharides and polysaccharides.

Reaction with Alcohols

What type of reaction of carbohydrates is the following definition?

Alcohols on monosaccharides can react with PO3 (-2) to form high energy phosphorylated intermediates in metabolism

formation of phosphate alcohols

What is a reducing sugar?

A carbohydrate with an anomeric carbon as part of a hemiacetal group ie. The anomeric carbon is not involved in a glycosidic bond.

True or False

Can Ketoses be considered a reducing sugar?

true

true or false

A reducing sugar is a carbohydrate, whose aldehyde group can be reduced to a carboxylic acid group

false

What is a glycosidic bond?

A bond between the anomeric carbon atom of a monosaccharide and -OR group. (alternate name for acetal group when found in carbohydrates)

true or false

The glycosidic bond configuration of alpha or beta is determined by the configuration of the anomeric carbon involved in the glycosidic bond

true

True or false

Eating candy can cause the bacteria that feed on sucrose to increase their numbers and subsequently cause tooth decay by changing the pH in your mouth

true

Which artificial sweetener resembles table sugar?

- steveioside

-aspartame

- saccharine

- sucralose

sucralose

MEMORIZE

What are the roles of carbohydrates in your body?

- are a source of energy

- become phosphorylated to make high energy intermediates in metabolism

- function as an anticoagulant and joint lubricants

- form receptors by attaching to proteins and lips present on the cell surface

- determine blood type by attaching to proteins on the red blood cell

MEMORIZE

What are the roles of carbohydrates in environment?

- become modified and form bacterial cell walls and the exoskeleton of invertebrates

- form polysaccharides that provide structural stability in plants

what is a phosphorylated sugar?

intermediates in energy generation and biosynthesis

what is chitin?

polysaccharide second in abundance in the natural world to cellulose (exoskeleton of lobster, beetles, etc.)

What is heparin?

Polysaccharide associated with connective tissue

What is the configuration of the glycosidic bond in heparin?

- alpha 1,4

- beta 1,4

- alpha 1, beta 4

alpha 1,4

What are glycoproteins?

sugars covalently bonded to proteins

The carbohydrates that determine blood type are covalently bound to membrane proteins and lipids ____________.

- present on the inside of the cell

- present on the outside of the cell

- present on the nucleus of the cell

- are not associated with a cell

present on the outside of the cell

Facts about polysacchardies - Cellulose

- most abundant polysaccharide

- beta-d-glucose unites linked by beta 1,4 glycosidic bonds

- fibrous substance that provides structure in plants

- humans do not produce the enzyme necessary to hydrolyze cellulose

- cellulose is indeigestible fiber in our dietys

- used to make materials for houses, cardboard and paper products

Cellulose is made up of repeating units of ______ that are linked by ________ glycosidic bonds and humans ________ digest

- Alpha-D glucose, alpha 1,4, cannot

- Alpha-D glucose, beta 1,4, can

- Beta-D glucose, beta 1,4, can

- Beta-D glucose, beta 1,4, cannot

beta-D-glucose, beta 1,4, cannot

Facts about polysaccharides - plant starch

Amylose: 20% of plant starch, polymer of alpha 1,4 D-glucose

Amylopectin: 80% of plant starch, Energy storage in seed, polymer of alpha 1,4 D-glucose with branches of alpha 1,6 D-glucose

Facts about polysaccharides: Glycogen vs Amylopectin

- Glycogen is found in Animals, and is an energy storage (liver and muscles)

- Amylopectin is found in Plants

- Glycogen is similar to amylopectin only more branches

- Glycogen: 10^6 glucose/molecule

- Amylopectin: 10^5 glucose/molecule

Glycogen is made up of repeating units of _______ that are linked by _______ glycosidic bonds and humans ______ digest

- Alpha-D glucose, alpha 1,4, can

- Alpha-D glucose, beta 1,4, can

- Beta-D glucose, alpha 1,4, can

- Beta-D glucose, beta 1,4, cannot

Alpha-D glucose, alpha 1,4, can

MEMORIZE

Carbohydrate Metabolism

What is Glycolysis

Conversion of glucose to pyruvate

MEMORIZE

Carbohydrate Metabolism

What is Gluconeogenesis

Synthesis of glucose from amino acids, pyruvate and non-carbohydrates

MEMORIZE

Carbohydrate Metabolism

What is Glycogenesis

Synthesis of glycogen from glucose

MEMORIZE

Carbohydrate Metabolism

What is Glycogenolysis

breakdown of glycogen to glucose

MEMORIZE

Carbohydrate Metabolism

What is Pentose Phosphate Pathway

Conversion of Glucose to five-carbon sugar phosphate

MEMORIZE

Carbohydrate Metabolism

What is Ribose

used in nucleic acid synthesis

MEMORIZE

true or false

coenzymes needed for lipid biosynthesis

true

Ways to remember what the definitions are and what they mean for carbohydrate metabolism

- Glycolysis = Glyco (glucose) + Lysis (breakdown)

- Gluconeogenesis = Glucose (glucose) + neo (new) + genesis (creation)

- Glycogenesis = Glycogen + genesis (creation)

- Glycogenolysis = glycogen + lysis (breakdown)

Which carbohydrate metabolic pathway produces ribose for nucleic acid production?

- glycolysis

- gluconeogenesis

- pentose phosphate pathway

- glycogenolysis

pentose phosphate pathway

What is the purpose of glycolysis?

- breakdown glycogen to glucose-6-phosphate

- convert glucose to two molecules of pyruvate while producing energy

- convert pyruvate to glucose

- convert glucose to ribose

convert glucose to two molecules of pyruvate while producing energy

What are Glycolysis? What are the parts of the energy investment and energy generation phase?

PURPOSE: convert glucose to two molecules of pyruvate while producing energy

ENERGY INVESTMENT PHASE: (STEPS 1-5)

- activation by phosphorylation

- 2 atp invested

- cleavage of one 6-carbon sugar to two 3-carbon sugar phosphate

ENERGY GENERATION PHASE: (STEPS 6-10) (occurs twice for every glucose molecule)

- generation of a " super-high energy " compound

- production of 2 atp

- generation of a " super-high energy " compound

- production of 2 atp

Glycolysis (anaerobic) STEP 1:

step purpose, is it endergonic and exergonic? and how is it regulated.

PURPOSE: convert glucose to two molecules of pyruvate while producing energy

STEP 1: glucose is phosphorylated

(why? phosphorylation of glucose traps it inside the cell and "actives" glucose by making it into a high energy molecule)

EXERGONIC; NOT REVERSIBLE

REGULATION: G-6-P is a negative allosteric regulator of hexokinase

Glycolysis (anaerobic) STEP 2: step purpose

PURPOSE: Glucose-6-P is isomerize to fructose-6-P i.e aldose to ketose

Glycolysis (anaerobic) STEP 3: step purpose, Regulation, and main points

PURPOSE: another molecule of atp is used to phosphorylate F-6-P to F1,6BP

MAIN POINT:

- at this point glucose is committed to glycolysis

- major control point

REGULATION:

- ATP & citrate are negative allosteric regulators

- ADP or AMP positive allosteric regulators

Why is the conversion of fructose-6-phosphate to fructose-1-6-bisphosphate highly regulated?

- it is not reversible

- it is highly endergonic

- it is the omitted step of the pathway

- it is a couples reaction

it is the committed step of the pathway

Glycolysis (anaerobic) STEP 4

- a six carbon sugar is cleaved into two 3-carbon molecules

- this is the step (step 4) from which this pathway derives its name

Glycolysis (anaerobic) STEP 5

- Convert a ketose to aldose as Glyceraldehyde 3-P can continue thru glycolysis

- Entry of fructose in liver

Glycolysis (anaerobic) STEP 6

- Gly 3-P is oxidized to a carboxylic acid that is phosphorylated

- NADH coenzyme produced

Glycolysis (anaerobic) STEP 7

- ATP is produced

- substrate level phosphorylated

Glucose must be converted to _____ in order for the energy production phase of glycolysis to proceed.

- two molecules of pyruvate

- two molecules of dihydroxyacetone phosphate

- two molecules of D-glyceraldehyde-3 phosphate

- one molecule of dihydroxyacetone phosphate

two molecules of D-glyceraldehyde-3 phosphate

Glycolysis (anaerobic) STEP 8 & 9

The purpose of steps 8 & 9 are to transfer the phosphate group to a position higher in energy, so that another ATP can be generated in Step 10

Glycolysis (anaerobic) STEP 10

- highly exergonic; i.e. not reversible

- atp is produced

- Allosterically regulated

(+) F1,6 Bis Phosphate

(-) high energy molecules (Acetyl-CoA, ATP), alanine, cAMP

Why is pyruvate considered to be more oxidized then glucose?

- each carbon has more covalent bonds to oxygen then glucose

- each carbon has more covalent bonds to hydrogen then glucose

- it is only a three carbon molecule

- glucose can donate hydrogen bonds

each carbon has more covalent bonds to oxygen then glucose

What is fermentation?

the production of energy under anaerobic conditions

True or False

Pyruvate is converted to lactate when there is a lack of oxygen in order to oxidize NADH for use in step 6 of glycolysis

True

True or False

Red blood cells convert pyruvate to acetyl-CoA during cellular respiration

False

What is Eukaryotic Cell?

found in some single celled organism and all plants and animals

The formation of Acetyl-CoA: Regulations, Complex, and types of enzymes

PYRUVATE DEHYDROGENASE COMPLEX

- complex is not a single enzyme

THREE DIFFERENT MAIN ENZYMES (>50 copies)

1, Pyruvate Dehydrogenase

- Coenzyme = TPP (Vitamin B1)

2, Dihydrolipoyl Transacetylase

- Coenzyme = CoA-SH & Lipoid Acid

3, Dihydrolipoyl Dehyrdogenase

- Coenzyme = NAD+ & FAD

REGULATION:

1, Allosteric

(-) negatively regulated by high energy molecules

(acetyl-CoA, ATP, & NADH)

(+) positively regulated by low energy molecules

(NAD+, AMP & CoA-SH)

2, Covalent Modification

- phosphorylation (inactive)