Carbohydrates Part 1 Flashcards by Jewel Brown

What is a carbohydrate? What is it composed of?

Biomolecules consisting of C, H, and O atoms
Primary energy source for metabolic processes

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What are saccharides? What are the 4 types and examples of each?

A group that includes sugars, starch and cellulose
Monosaccharides- sugars, glucose
Disaccharides- lactose, sucrose
Oligosaccharides
Polysaccharides- starch, glycogen

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Describe Monossacharides. How many carbons? What are they defined by?

Simple sugars
3-9 C atoms
Defined by location of carbonyl group

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Describe Aldose. Where is the location of the carbonyl group? What kind of group is it?

Monosaccharide
Carbonyl group is on endmost C atom
Aldehyde group

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Describe Ketose. Where is the location of the carbonyl group? What kind of group is it?

Monosaccharide
Carbonyl group within sugar backbone
Ketone group

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What is a functional group?

Characteristic groups in organic molecules that give them their reactivity

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What is a chiral carbon on a monosaccharide?

4 different atoms or groups of atoms attached
C atom farthest from the carbonyl group

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What is the orientation of the OH group within D-sugar? What sugar exists naturally in this form?

On the chiral center on the right
Glucose

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What is the orientation of the OH group within L-sugar?

On the chiral center on the left

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Which glucose (D or L) is the natural form? What is their relationship to each other?

D glucose is the natural form
Enantiomers

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Are monosaccharides soluble in water? By what process do they form rings? What is the significance of this phenomenon?

Soluble in water
Form rings via internal cyclization
Thermodynamically more stable form

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What is a pyranose ring?

Ring with 5C and 1O atom forms
The hydroxyl group on carbon 5 reacts with aldehyde at carbon 1

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What is a furanose ring?

Ring with 4 C and 1 O atom forms
The hydroxyl on carbon 4 reacts with the aldehyde at carbon 1

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How is a hemiacetal formed? What do they contain?

Formed when an alcohol reacts with an aldehyde
Contain alcohol (OH) and an ether (OR) group attached to the same carbon

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What are anomers?

Geometric variation of cyclic sugars

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What is the most common form of glucose at equilibrium in aqueous?

Pyranose

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Define glycosides/glycosidic bonds/linkage. What portions of the carbohydrate are involved?

Covalent bond that joins carbohydrate (sugar) to another carbohydrate (sugar) to form disaccharide
Hydroxyl group of carbohydrate and hydrogen of another sugar or organic molecule
Ex: glucose and galactose can form Lactose structure

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What is a glycosidic bond? What is a glycoside? What atoms may be involved with this bond?

Sugar (OH group) may form a glycosidic bond with another biomolecule that is not a carbohydrate (can be between sugar and sugar or sugar and non carbohydrate
Substance containing a glycosidic bond
O, N, S, or C

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What is a nucleotide? What is a nucleoside, what bond is involved? What are the 5 nitrogenous bases?

Phosphate, ribose sugar and nitrogenous base
Ribose sugar and nitrogenous base (linked by glycosidic bond)
Adenine, guanine, cytosine, thymine, uracil

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Is the dominating form of D-glucose the open chain form or the furanose form?

Furanose ring

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What is formed when monosaccharides (alcohols) react with acids?

Esters

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What are the three components of a nucleoside triphosphate? (ATP) What does it function as?

Nitrogenous base adenosine
Sugar ribose
Triphosphate
Energy source

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What are the contents of the enzyme Nicotinamide Adenine Dinucleotide? (NAD)

Adenine (nitrogenous base)
2x the sugar ribose
2x phosphate
Nicotinamide (form of vitamin B3)

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What is NAD involved in?

Coenzyme involved in oxidation reduction reaction
Glycolysis, fatty acid oxidation, TCA cycle, mitochondrial respiratory chain

What is NADP+? How is it formed? How is NADPH formed?

Universal electron carrier Additional phosphate added to NAD+ NADPH formed form NADP+ through pentose pathway to glucose-6-phosphate dehydrogenase

What occurs during reduction of D-Ribose? What is produced?

Carbonyl group of aldehyde is reduced to an alcohol Results in reduced sugar (D-ribitol)

What are the components of flavin adenine dinucleotide (FAD)? What reactions is it involved in?

Adenine Sugar ribose 2x phosphate (diphosphate) Riboflavin (vitamin B2) Redox active metabolic reaction

Is FAD an oxidizing or reducing agent? What occurs when it goes through the opposite process?

FAD is oxidizing agent and is reduced to FADH 2 FADH2 is reducing agent and is oxidized to FAD

What is hyperglycemia?

High blood sugar Diabetes

How do glucose, sucrose and fructose compare to each other when considering sweetness? (Least to most)

Glucose Sucrose Fructose (sweetest common sugar, less calories b/c less is needed)

How do artificial sweeteners compared to real sugars? What kind of effects do they have on the body?

More sweet Can cause changes in stomach bacteria leading to inflammation, obesity, heart disease and diabetes

What are disaccharides? What are they joined together by? What are 3 examples?

2 monosaccharides joined but a glycosidic bond Ex: sucrose, maltose, lactose (milk sugar?

What enzyme to deficient in lactose intolerance? When does lactose intolerance form?

Lactase Almost everyone is born with ability to digest it (breast milk), can develop at any age

How many monosaccharides are joined in oligosaccharides?

3-10

How many monosaccharides are joined in polysaccharides? What are some examples?

More than 10 Glycogen, starch, cellulose (polymers of D/glycose)

What is starch? What is it produced by? What does it consist of?

Polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds (white, tasteless, odorless) Produced by most green plants for energy storage Consists of amylose and amylopectin

What can a starch be processed into?

Sugars used in processed food Sugars and then fermented to produce ethanol for alcohol

What is glycogen? Where can it be found/ made? What are the 2 forms?

Polysaccharide of glucose, serves as energy storage In animals, fungi and bacteria Produced and stored in cells of the liver and skeletal muscle Two forms: glycogen for short term, triglyceride in adipose tissue for long term

What controls glycogen breakdown? What is made from this breakdown?

Glucagon Peptide hormone is produced

How does liver glycogen function?

Short term energy Responds to blood glucose level Liver does not use glycogen for its own energy needs

How does muscle glycogen function?

Provides readily avaible source of glucose during exercise Supports anaerobic and aerobic Muscle cannot release glucose into blood due to lack of glucose-6-phosphatase

Besides the liver and skeletal muscle, where else can small amounts of glycogen be found?

Kidneys, RBC, WBC, glial cells in the brain, uterus during pregnancy to nourish embryo

Where within the cell is glycogen stored?

Stored in the cytoplasm of animal cells for food energy Forms energy reserve

What are glycosaminoglycans (GAGs)? What roles do they have in the cell/body?

Structural carbohydrates Role in cell signaling, regulation of cell growth, proliferation, promotion of adhesion, anticoagulation, wound repair, lubricant

What else are GAGs called? Where are these found? What are two examples?

Mucopolysaccharides because of viscous, lubricating properties Found in mucous secretions (ex: bladder lining protection from urine) Ex: hyaluronic acid, heparin sulfate

What is the charge and structure of GAGs (mucopolysaccharides)? What are they a part of?

Negatively charged Long linear polysaccharides consisting of repeating disaccharide units Part of proteoglycans (ex: cornea)

Describe the structure of a glycosaminoglycan.

Repeating two-sugar unit consists of an uronic sugar and an amino sugar => amine group replaced hydroxyl group (OH)

What is hylauronic acid? Where is it found? What is its function?

Anionic, non-sulfated glycosaminoglycan distributed throughout tissues Part of ECM for cell proliferation and migration, progression of malignant tumors, wound repair

What is the function of the hylauronic acid in the eye? What can it be used to treat?

Lubricant Present in corneal endothelium and tears Dry eye treatment Lowers inflammation speeds up healing

Which proteoglycan is important in neural development and also contributes to glia scar formation – hence preventing axonal growth (regeneration)?

Chondroitin sulfate proteoglycan (CSPGs)

What is heparin sulfate composed of? What is its function? where can it be found in the eye?

Glucuronic acid (GlcA) linked to N-acetylglucosamine (GlcNAc) Regulation, development, angiogenesis, blood coagulation, tumor metastasis All retinal layers, choroid

What is heparin?

A medication and naturally occurring glycosaminoglycan Treats heart attacks

What is chondroitin sulfate? Where can it be found?

Sulfated glycosaminoglycan Attached to proteins part of proteoglycan Structural component of cartilage

What are proteoglycans? What does it consist of? Where can it be found?

Heavily glycosylated proteins Consists of core protein with covalently attached GAG chain Found in connective tissue

Which proteoglycan is the major PG in the cornea?

Keratan sulfate

What is Chondroitin sulfate proteoglycan (CSPGs) a structural component of?

Cartilage

What are glycoproteins?

oligosaccharide chains (glycans) covalently bound to the polypeptide chain increase of hydrophilic nature of the protein

What is a form of glycosylation resulting in creating a membrane anchor?

Glypiation