Biochem test chapter 7

Sucrose

Common table sugar produced in the leaves and stems of plants, 1 molecule of glucose linked to 1 molecule of fructose linked by a A,B (1,2) glycosidic bond, a non-reducing sugar

Glycoproteins

Commonly defined as proteins that are covalently linked to carbs through N- and O- linkages

When humans consume ethanol , the first step in its metabolism is

Conversion to acetylaldehyde and the nacetic acid is formed from the aldehyde

What can all carbohydrates be considered to have derived from

D-glyceraldehyde or non-chiral dihydroxyacetone

Which of the following terms best describe an enzyme that catalyzes electron transfer reactions

Dehydrogenase

D-allows and D-galactose classfiy

Diastereomers

Epimers

Diastereomers that differ at a single chiral carbon

Proteoglycans

Distinguished from other glycoproteins by their increase carb content, occur on cell surfaces or are secreted to the ECM

Glycolysis

Do not require 02 to generate energy

D-ribose and L-ribose classify

Enantiomers

___________________ are nonsuperimposable , non mirror image stereoisomer

Enantiomers

PPP substrate and product

Glucose-6-phosphate NADPH, Ribose

Write the net reaction for glucoes —— lactate in fermentation

Glucose= 2 ADP + 2 Pi = 2 lactate, 2 ATP

Write the net reaction for glucose——— pyruvate in glycolysis

Glucose= 2 NAD+ + 2 ADP + 2 Pi = 2 ATP + 2NADH + 2 H2O + 2 pyruvate + 2H+

Polysaccharide

Glycans are composed of large #'s of monosaccharides connected by glycosidic linkages

The equilibrium for isomerization of dihydroxyacetone phosphate to glyceraldehyde-3-phosphate is favored because

Glyceraldehyde-3-phosphate is being continuously drained off for the subsequent reaction in the glycolytic pathway

Slightly different versions of a glycan component of glycoprotein are called _______________

Glycoforms

Glycogen breakdown substrate product

Glycogen glucose, glucose-6-phosphate

How are the linkages named in disaccharides

In the alpha (1,4)or beta (1,4) conformation and by which carbons are connected

Where does fructose enter glycolysis

In the liver which is phosphorylated into fructose-1,6-phosphate and breaks down into hydroxyacetone and glyceraldehyde. This is not good cause it is not regulated by hexokinase and PFK

Where are sulfate esters of carb molecules formed

In the proteoglycan components of connective tissue that take part in the formation of salt bridges between carb chains

What type of forms can participate in redox reactions

Open chain forms

Proteoglycans roles

Organizing ECM signal transduction metabolism of proteoglycans involved in many genetic disorders in clouding hurler's syndrome

Glucose

Originally called dextrose, found in large quantities throughout the natural world. Primary fuel for living cells preferred energy source for brain cells and cells without mitochondria

Is mutarotation spontaneous or nonspontaneous

Spontaneous process that produces an equilibrium mixture of both alpha and beta forms in both pyranose and furanose ring structure

In the down position what is it called

Alpha

In the conversion of glyceraldehyde-3-phosphate to 1,3 bisphosphoglycerate

An aldehyde is oxidized to cartboylic acid

Acetal linkage

An arrangement where 2 organic molecules are connected through an a 0-ch-o functional group

Oligosaccharide

An intermediate sized carb composed of 2-10 monosaccharide

D-glycan

An oligosaccharide linked to a protein bi an a;pha glycosidic bond to the hydroxyl oxygen of serine or threonine residues

N-glycan

An oligosaccharides linked to a protein via a B-glycosidic bond between the core N-acetylglucosamine anomeric carbon and a side chain nitrogen of an asapragine residu

Furan

An organic molecule with a 5 sided ring containing 1 oxygen atom

Pyran

An organic molecule with a 6 sided ring containing one oxygen atom

Anaerobic metabolism can occur in all these organism or cells except

Anaerobic metabolism can occur in all of these

_________________ are stereoisomers of sugars that differ only in the configuration at an acetal or ketal carbon

Anomer

Glycosaminoglycans (GAG)

Are linear polymers with disaccharide repeating units

Where is the most oxidized C found in a sterioisomer

At the top

O-linkage

Attached by a side chain of AA with an OH (Sergio nine and threonine)

N- linkage

Attached by side chain of protein asparagine

In the up position what is it called

Beta

Lectins

Binding proteins that are involved in translating the sugar code

The reduction of pyruvate to lactate

Allows for the recycling of NAD+

In the conversion of glucose to pyruvate, how many of the actual steps involve electron transfer

1

Anomer

1 of 2 possible diastereomers that they may form during the cyclization reaction of a hemiacetal or hemiketal

What is the net ATP yield per glucose during glycolysis

2

The first 5 reactions of glycolysis transform each glucose molecule that enters into

2 molecules of glyceraldehyde-3-phosphate

Anomers

2 possible diastereomers that form because of cyclization

There are approximately ________________ protein coding genes in the humam genomej

20k

Glycosidic linkage

A ancestral linkage formed between 2 monosaccharides

Glycolipid

A complex lipid molecule in which a monosaccharide, disaccharide or oligosaccharide is attached to a membrane lipid molecule through an o-glycosidic linkage

Lactone

A cyclic esster

Cellobiose

A degradation product of glucose linked with a B(1,4) glycosidic bond, does not exist freely in nature

Methanol is extremely toxic, but not directly. In the body, it is converted into formaldehyde; that's what's actually the poison. What kind of enzyme catalyses this conversion?

A dehydrogenase

Disaccharide

A glycosidic composed of 2 monosaccharides

Amino sugars

A hydroxyl group usually on carbon 2 is replaced with an amine group

Glycosaminoglycan

A long unbranched heteropolysaccharide chain composed of dissaccharide repeating units

Epimer

A molecule that differs from the configuration of another isomerby one asymmetric center

Ketose

A monosaccharide with a ketone functional group

Aldose

A monosaccharide with an aldehyde functional group

What is -2-deoxy-d-ribose found

A penthouse sugar found in DNA

Monosaccharide

A polyhydroxy aldehyde or Kentone containing at least 3 carbon atoms

Glycan

A polymer of monosaccharides; a polysaccharide

The reaction of fructose 1,6 bisphosphate to give glyceraldehyde-3-phosphate and dihydroxyacetone phosphate is an example of

A reverse Aldo condensation

Amadori products

A stable ketoamine formed from the rearrangement of a chiff base; an intermediate in glycation processes that produce advanced glycation end products

Alditol

A sugar alcohol; the product of the reduction of the aldehyde or ketone group of a monosaccharide

GPI anchor

A sugar and phosphate containing molecule that links peripheral proteins to membranes.

Reducing sugar

A sugar that can be oxidized by weak oxidizing agents

Amylose

A type of plant starch that is unbranched polymer of D-glucose residues linked with a 1,4 glycosidic linkages

Fructose can be found in

ABO blood group determinants

Which of the following exercises allosteric control in the reaction of phosphofructokinase

ATP fructose-2,6-bisphosphate

In humans, pyruvate can be converted to

Acetyl CoA and lactate

Explain how fructose-2,6-bisphosphate is created and degraded in the cell, how the metabolism of fructose-2,6-bisphosphate is regulated and the effect fructose-2,6-bisphosphate has on glycolysis and gluconeogenesis

Activator of glycolysis made from phosphofructose kinase 2 catalyzes to fructose-6-phosphate uses enzyme phosphates to fructose-6- bisphosphate in gig glucose activates glycolysis by activation on PFK2 and the nfructose 6 to 6-bisphosphate glucose bocks and works opposite

Amadori products can further react to form

Advanced glycation end products

Oxidation of the aldehyde group of sugar produces a(n) _______________ acid

Alditol

Which of the following enzymes catalyzes the cleavage of fructose bisphosphate into two 3C units

Aldolase

Oxiationof the aldehyde groups of a sugar produces a(n) ________________ acid

Aldonic

D-glyceraldehyde and dihydroxyacetone classify

Aldose-ketose pair

Diastereomers

All stereoisomers that are not enantiomers (Mirror images)

Fate of pyrucate

CAC lactate ehtnaol

During anaerobic metabolism in yeast, the carbons of glucose end up in

CO2 and ethanol

Glyceraldehyde structure

COH-CH(OH)-CH2OH

Where can the hydroxyl group on a hemiacetal occur on the carbon 1

Can be up above the ring or down position below the ring

Glycoprotein

Carb containing proteins; mono,di and oliogosacchariade that are covalently linked through N- or O- linkages

Which groups on monosaccharides can undergo several chemical reactions

Carbonyl and hydroxyl

Ligands bind specifically to ________________ by _______________

Carbs, hydrogen bonding, van Dee walls and hydrophobic interactions

___________________ is the structural glucose containing polysaccharide of plants

Cellulose

Dihydroxyacetone structure

Ch2(OH)-CO-CH2OH

Starting carbohydrate final carbon product yield of ATP Yield of NADP

Glucose pyruvate, lactate 2,2'2,0

Starch

Energy reservoir of plant cells and a significant source of carbs in human diet

Glycogen

Energy storage molecule in animals composed of glucose residues linked by a 1,4 and alpha 1,6 linkages

Starch and glycogen are what

Energy storage molecules

What is the wide variety of cellular functions that carbs have

Energy structure communication precursors for other biomolecules

D-Erythrose and D-threes are referred to as _____________ because of their structures only differ in the configuration at one asymmetric carbon atom

Epimer

Classify D-erythropoietin and D-threose

Epimers

D-glucose and D mannose classify

Epimers

What is the transformation of glucose referred to as

Erpimerization

Which of the following in not true

Every reaction in a metabolic pathway much have a negative DG, or the pathway cannot run

The reactions where glucose is converted to glucose-6-phosphate and fructose-6-phosphate is converted to fructose1,5 bisphosphate are examples of

Exergonic reactions priming reactions phosphorylation reactions kinase reactions

Ketal

Formed from the reaction of a hemiketal with an alcohol

Esterification

Free OH groups of carbs can be converted to esters by reactions with acids

Cyclic form of fructose is called

Fructofuranose

Which of the following in not an end product of glucose metabolism via either aerobic or anaerobic means

Fructose

The phosphorylation of fructose-6-phosphate to fructose-1,6-bisphosphate is the committed step in glycolysis because

Fructose-1,6-bisphosphate can undergo no other reactions than those of glycolysis

The order of compounds in the conversion of glucose to pyruvate acid is as follows: PEP

Fuctose-6-phosphate, fructose-bisphosphate, 1,3-phosphoglyceric acid, 3-phosphoglyceric acid, PEP

5 membered rings are called

Furanoses

Galactosemia

Genetic disorder

Glucose in the pyranose form is called

Glucopyranose

The acetal of glucose and the ketals of fructose are called _____________ and _____________, respectively

Glucosdies, fructosides

Glycolysis substrate and product

Glucose pyruvate

Gluconeogenesis product and substrate

Glucose pyruvate, glycerol, lactate

In glycoproteins, what are the 3 AA residues to which carbs are most frequently linked? To what functional groups is the glycan linkedin eachcasae

Glycoproteins, carb moieties are most frequently linked to the aside nitrogenof asparagine and hydroxyl oxygen of serine and threonine residues

When catalyzed by glycosyl transferases what happens

Glycosidic bonds are formed between anomeric carbons in certain glycans and oxygen or nitrogen of other types of molecules, resulting in N- or O- bonds

Homoglycans

Have 1 type of monosaccharides and are found in starch, glycogen, cellulose and chitin (glucose monomer)

How do glycosidic formations form

Hemiacetal and hemiketals react with alcohols to form the corresponding acetal or ketal

Polysaccharides that contain more than one type of monosaccharides are called _______________________

Heteroglycans

What are the most abundant carbs in living cells

Hexoses and pentoses

Reactive carbonyl containing product

Highly reactive molecules produced from amadori products that cause protein linkages and adduct formation, the discard only compound glyoxal CHOCHO is an example

What classes have been polysaccharides been divided into

Homoglcans and heteroglycans

Starch

Homoglycan containing glucose monomers linked by alpha 1,4 glycosidic bond with branch points connected by alpha 1,6 glycosidic bonds

5 classes of GAGs

Hyaluronic acid chondroitin sulfate dermatan sulfate heparin and heparin sulfate keratin sulfate

When can lactose be produced in monosaccharide

If the carbonyl groups of idonic or uronic acids react with an OH group in the same molecule

Monosaccharide stereioisomer

Increase in # of chiral carbons increases the # of possible optical isomers

Heteroglycan

Increase molecular weight carb polymers that contain more than 1 type of monosaccharides

Homoglycan

Increase molecular weight carb polymers that contain only one type of monosaccharide

ATP acts as an important modulator of metabolic regulation. What is the effect of increasing cellular levels of ATP on phosphofructosekinase and hexokinase

Inhibits them

Thiamine pyrophosphate is a coenzyme

Involved in transfer of 2C groups

The phosphorylation of glucose to glucose-6-phosphate

Is an endergonic reaction that takes place because it is coupled to the exergonic hydrolysis of ATP

Maltose

Is an intermediate product of starch hydrolysis alpha (1,4) linkage between 2 molecules of glucose, does not exist freely in nature

Which of the following enzymes interconverts an aldose and a ketose

Isomerase

Which of the following terms describe an enzyme that transfers a phosphate group from ATP to a substrate

Kinase

Uronic acids

L-alpha-D-glucuronate and it's epidermis B-L-iduronate important in animals

During anaerobic metabolism in RBC, the carbons of glucose end up in

Lactic acid

_____________ is a dissacharide in which galactose is linked to glucose by a b-glycosidic linkage

Lactose

Proteoglycan

Large molecule containing large # of glycosaminoglycan chains linked to a core protein molecule

Polysaccharides can be

Linear or branched

Where is the greatest abundance of glycogen carbs stored in vertebrates

Liver and muscle

Oligosaccharides

Made up of smaller glycan of 10-15 monomers that are most often attached to polypeptides as glycoproteins

Lactose

Milk sugar- the disaccharide found in milk, 1 molecule of galactose linked to 1 molecule of glucose B(1,4) linkage

The fate of pyruvate produces during glycolysis depends primarily on the availability of

Molecular oxygen

Glycoconjugate

Molecule that possess covalently bond carb groups

Oxidation

Monosaccharides may readily undergo several oxidation reactions in the presence of metal ions or certain enzymes (aldehyde group)

Deoxy sugars

Monosaccharides that have an -OH replaced by and -H or -CH3

Isomerization

Monosaccharides that undergo several types of isomerization

Maillard reaction

Most researched example of the glycation reaction in the nonenzymatic glycation

_________________ is a glycoprotein component of ______________ a slippery substance that protects the surfaces of several cell types

Mucin and mucus

2 types of broad classes of oligosaccharides

N and O

Major types of heteroglycans

N- sand O- glycosaminoglycans glucosaminoglycans glycan components of glycolipids GPI anchors

Consider the following reaction catalyzed by lactate dehydrogenase and answer the following questions Pyruvate + NADH + H+ ——- lacatate+ NAD+ what is the reactant what reactant is being reduced what is the reducing agent what is the oxidizing agent

NADH pyruvate NADH pyruvate

Galactose

Necessary to synthesize a variety of important biomolecules like lactose, glyocolipids, phospholipids, proteoglycan and glycoproteins

Cellulose is

Nonreducing

Ribose is

Nonreducing

Sucrose is

Nonreducing

What is a starch

Nonreducing

Glycoproteins functions

Occur in cells as soluble and membrane bound forms and are nearly ubiquitous in living organisms

Acetal

One of a family of organic compounds with the general formula RCH(OR')2, formed form the reaction of a hemiacetal with an alcohol

Hemiketal

One of the family of an organic molecules with the general formula RRC(OR)OH that is formed by the reaction of a molecule of alcohol with a ketone

Hemiacetal

One of the family of organic molecules with the general formula RCH(OR)OH that is formed by the reaction of a molecule of alcohol with an aldehyde

Enterocyte

One of the numerous cells that line the small intestine; absorbs digested nutrients such as monosaccharides

Study the structure 1,3 bisphospholgycerate, an intermediate in glycolysis. Describe the chemical bond linkage for each phosphoryl group in the molecule. Why is the phosphoryl group linked to the carboxyl group more reactive than the phosphoryl group linked to the hydroxyl group

Phosphoanydride is more reactive than esters

Which enzyme is the key regulatory enzyme in glycolysis

Phosphofructokinase

Amylopectin

Plant starch that is the branched polymer containing an 1,4 and a 1,6 glycosidic linakges

__________________ are molecules with no foxed molecular weights

Polysacchardies

6 membered rings are called

Pyranoses

In aerobic metabolism, what is the fate of pyruvate by glycolysis

Pyruvate loses carbon dioxide, and the remaining two carbon atoms become linked to coenzyme a

If oxygen is available

Pyruvate will be converted to Acety-CoA and go into the CAC

Fructose is

Reducing

Sugars that react with Benedict's reagent are called _____________________

Reducing sugars

Optical isomers

Referenced carbon is the asymmetric carbon farthest from the carbonyl carbon

Fructose

Referred to as fruit sugar, 2x sweeter than sucrose ; used as sweetening agent in processed food

If glycolysis did not lead to the production of ATP, the overall process would

Release more energy

Glycoconjugates

Result from carbohydrates being linked to protein and lipids

The produce of the reaction between an aldehyde or ketone and an anime is called a _____________ base

Schiff

Amadori product

Schiff base that forms rearranges to a stable ketoamine

The _______________ are a family of lectins ont he surface of endothelial cells that act as a cell adhesion molecules

Selectins

Reduction of aldehyde group of a monosaccharide yields a ____________

Sorbitol

The enzyme glucokinase

Specifically phosphorylated glucose rather than other sugars

What is the structural differences between characterized starch, cellulose and glycogen

Starch and glycogen are branched and connected by a-1,4 linkages and 1,6 glycogen is way more branched than starch. Cellulose is a linear polymer of glucose linked by b-1,4 bonds

Diastereomer

Stereoisomers that are not mirror images of one another

Chitins purpose is what

Structural

Haworth structures

Structures more accurately depict bond angle and length in ring structures than the original Fischer structure

Reduction

Sugar alcohols (alditols) are produced by the reduction of aldehyde to ketone groups of monosaccharides used in processing and pharmaceuticals

What does the esterification of monosaccharides drastically change

Sugars chemical and physical properties

Reducing sugars

Sugars that can be reduced by weak oxidizing agents like Benedict's reagent needs an open chain so all Aldoses are reducing sugars and ketoses such as fructose and also due to isomerization

_______________ and ______________ are examples of heparin sulfate proteoglycans

Syndecans and glypians

Animals such as ___________ can use cellulose as an energy source

Termites

What structural relationship is indicated by the term D sugar? What are + glucose (shifts polarized light to the right) and - fructose (shift polarized light to the left) both classified as D sugars?

The OH on the chiral carbon furthest from the carbonyl group is on the right side in a Fischer projection formula. So both + glucose and - fructose and D-sugars despite their rotation of the plan polarized light in opposite directions

Glycoside

The acetal form of a sugar

Disaccharide

The acetal linkage is formed between the hemiacetal hydroxyl of one monosaccharide and the hydroxyl of another

How do ring formations occur

The aldehyde and Kenton groups react reversible with hydroxyl groups in an aqueous solution to form hemiacetals and hemiketals

Mutarotation

The alpha and beta forms of monosaccharides are readily inter converted in aqueous environments

Glycosidic linkage formed

The cyclic hemiacetal or hemiketals form of the monosaccharide reacts with an alcohol

Celloiose

The disaccharide product of cellulose degradation; 2 molecules of glucose linked by B 1,4 glycosidic bond

To tell whether the molecule is D or L what chiral carbon do you look for

The furthest chiral carbon from the most oxidized carbon

Schiff base

The imine product of a reaction between a primary amino group and carbonyl group

Enediol

The intermediate formed during the isomerization reactions of monosaccharides. It contains a double bond with a hydroxyl group on each carbon of the double bond.

Cellulose

The primary component of plant cell walls

Chitin

The principal structural component of the exoskeletons of Arthropoda and the cell walls of many fungi

Alaric acid

The product formed when the aldehyde and CH2OH groups of a monosaccharide are oxidized to carbolic acids

Uronic acid

The product formed when the terminal CH2OH group of a monosaccharide is oxidized

Adduct

The product of an addition reaction

Aldonic acid

The product of the oxidation of the aldehyde group of monosaccharides

Define the term reducing sugar and what structural feature does a reducing sugar have

The reducing sugar reduces CuII in Benedict's reagent. This reduction take place because the hemiacetal portion of a sugar can form an aldehyde functional group which can be oxidized to be carboxylic acid

Epimerization

The reversible inter conversion of epimers

Which of the following is required for substrate-level phosphorylation

The standard free energy of the hydrolysis reaction is more negative than that for hydrolysis of the new phosphate compound being formed

Why can aldoses and ketoses both behave as reducing sugars

They contain the required aldehyde and they are converted to aldoses in the alkaline reducing test

The fate of NADH from glycolysis depends open whether conditions are aerobic or aerobic

True

The DG values for glycolytic reactions at physiological conditions may be exergonic, even though the DG at standard conditions may be endergonic

True the Rt/Q ratio of the substrate/product is an important impact

Glycogen synthesis substrate and product

UDP-glucose glycogen

Glycogen synthesis product and substrate

UDP-glucose glycogen glycogen breakdown substrate and product

Monosaccharide derivatives

Uronic acids d- glucuronic acid amino sugars d-glucosamine and D-galactosamine deoxy sugars

D-glucuronic acid

Used in the liver to improve water solubility to remove waste molecules

Alcohol dehydrogenase resembles lactate dehydrogenase in that it

Uses NAD+ as a conenzyme

Lactate appears to be a dead-end waste product of the muscle cell that cannot be used for energy. Outline how it can be used to make glucose

Uses cori-cycle—lactate—blood stream —liver—glucose—muclse

How are gluconeogenesis and glycolysis regulated reciprocally

When glycolysis is activated gluconeogeneiss is inactivated

What is starch made up of

amylose and amylopectin

Glycosylation Reactions

attach sugar or glycans to proteins or lipids

How are carbs classified?

by the number of C atoms ie trioses, tetroses

What is the most abundant biomolecule in nature

carbohydrates

D-glucosamine (a) and D-galactosamine (b)

most common amino sugars often attached to proteins or lipids

In glycolysis, ATP is synthesized by

substrate-level phosphorylation