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69 Cards in this Set
- Front
- Back
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The 4 types of Carbohydrates are:
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Monosaccharides (M-sac)
Oligosaccharide (O-sac) Polysaccharide (P-sac) Glycoproteins |
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What 3 atoms make up all carbohydrates?
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Carbon
Hydrogen Oxygen |
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What is the formula for an unmodified m-sacc?
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(CH₂O)_n
where n >= 3 *There will be twice as many hydrogens as carbons and oxygens |
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Define:
M-sac |
The basic carohydrate unit. Many different types.
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Define:
O-sac |
Polymer of M-sac with 3-10 sugar components.
** O-sacs containing three or more residues are relatively rare, occurring almost entirely in plants. |
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Define:
P-sac |
M-sac's strung together (> 10 sugars)
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Define:
Glycoproteins |
Proteins with O-sac chains attached to their polypeptide side-chains
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What are 6 reasons carbohydrates are important
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1 - Energy from the sun captured by plants is first stores as carbohydrates.
2 - Oxidation of carbohydrates provides energy to sustain life 3 - Carbohydrates are stored as P-sac's. 4 - The building blocks for nucleotides 5 - Glycolipids are part of biological membranes 6 - They play a structural function in plants, insects and bacteria. |
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How do M-sacs differ from each other?
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They differ in the number of carbons and the arrangement of their hydrogens and oxygens.
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What 2 types of M-sacs are there?
How do you differentiate between them? |
Aldose and Ketose
Aldose - Carbonyl carbon is an aldehyde Ketose - Carbonyl carbon is a ketone |
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Define:
Carbonyl carbon |
Carbon double bonded to an oxygen
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What is the name of the smallest aldose carbohydrate?
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D-glyceraldehyde
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What is the name of the smallest ketose carbohydrate?
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Dihydroxyacetone
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In nature we rarely see M-sacs containing more than _____ carbons.
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...7...
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Define the physical structure of D-Glucose in terms of:
Aldose/Ketose # of chiral centers # of possible stereoisomers |
Aldose
4 chiral centers 16 possible stereoisomers (2^4 = 16) |
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What 3 important functions does D-Glucose perform?
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- Energy source
- Energy storage - Structural role in plants |
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How do you distinguish if a carbohydrate is in D or L configuration?
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Look at the *chiral* carbon farthest away from the carbonyl group.
If the -OH is on the right, it's D configuration. If the -OH is on the left, it's in L configuration. |
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In terms of drawing a carbohydrate, how do you switch between the D and L configuration?
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Position of -OH and -H around every *chiral* carbon will change.
Position of -OH and -H around non-chiral centers does not matter (in terms of switching between D and L) |
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The D and L forms of carbohydrates are mirror images of each other, also known as _____.
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...enantiomers.
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Which form of M-sacs (D or L) do we mostly see in nature?
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D-Monosaccharides.
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Define:
Epimer |
Two M-sacs differ from each other in the configuration of *one* chiral center.
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What happens to M-sacs in aqueous solutions?
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In aqueous solutions, M-sacs form cyclic structures with an *additional* chiral center.
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What is the structural difference between:
Pyranoses and Furanoses? |
Pyranoses have 6 members in their rings.
Furanoses have 5 members in their rings. |
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Define:
Anomeric Carbon |
The carbonyl carbon in a M-sac that cyclizes. (i.e. participates in forming a ring structure)
Upon forming a ring, the anomeric carbon will either be in the "α anomer" or "β anomer" configuration. |
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Define:
Anomers |
Stereoisomers that differ in α/β configuration.
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True/False:
Different anomers have different physical properties |
True.
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How do you tell the difference between an "α anomer" and a "β anomer".
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In the ringed structure for an α-anomer, the -OH is *opposite* the CH₂OH.
In the ringed structure for a β-anomer, the -OH is on the same side as the CH₂OH. |
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During cyclyzing of an M-sac, which carbon becomes the additional chiral center?
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The anomeric carbon
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Define:
Mutarotation |
Souce: Wiki
As a cyclic M-sac in solution will spontaneously switch between it's α and β forms |
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Pyranoses can assume _____ conformations.
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...chair...
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In chair conformation, the most stable form is established by putting the bulky side chains in the _____ position.
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...equatorial...
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True/False:
Pyranose rings are planar. |
False
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Uronic acids are formed by...
What suffix is appended to their parent aldose? |
...oxidizing the primary alcohol group of an aldose.
-uronic acid |
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Aldonic acids are formed by...
What suffix is appended to their parent aldose? |
...oxidizing the aldehyde group of an aldose.
-onic acid. |
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Derivatives of M-sacs:
What 2 acids can be produced from oxidizing an aldose? What can be produced through the reduction of an aldose? |
Gluconic Acid or Uronic Acid are produced from oxidizing an aldose.
Alcohol sugars are produced from reducing an aldose. |
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Another term for "alcohol sugars" is...
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...alditols.
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How are Amino Sugars formed?
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A hydroxyl group is replaced by an amino group.
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Define:
Glycosidic bond |
The covalent linkage between the anomeric carbon and an alcohol or an amine
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What is an N-Glycosidic bond?
How are they formed? |
Bond between an anomeric carbon and a nitrogen on an amine.
The anomeric -OH reacts with an amine. |
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What is an O-Glycosidic bond?
How are they formed? |
Bond between the anomeric carbon and an oxygen on an alcohol.
The anomeric -OH reacts with the hydroxyl (-OH) of an alcohol. |
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Another term for Polysaccharides is _____.
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...glycans.
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What type of bond links P-sacs together?
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The M-sacs that make up a P-sac are linekd together via glycosidic bonds.
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The most abundant D-sac is _____.
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...sucrose.
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Sucrose is formed from what two M-sacs?
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Glucose + Fructose
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Lactose is formed from what two M-sacs?
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Glucose + Galactose
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How is lactose formed?
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Lactose is formed by linking:
- the C₁ of Galactose in the β-configuration to... ...the C₄ of Glucose. |
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What type of sugar is Lactose?
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Lactose is a *reducing* sugar.
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Define:
Reducing sugar |
Saccharides bearing anomeric carbons that have not formed glycosidic bonds.
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Define:
Non-reducing sugar |
Saccharides bearing anomeric carbons that have all formed glycosidic bonds.
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How is sucrose formed?
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Sucrose is formed by linking:
- the C₁ of Glucose in the α-configuration with... - ...the C₂ of Fructose in the β-configuration |
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What type of sugar is sucrose?
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A non-reducing sugar.
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Define:
Starch |
A mixture of glycans that plants synthesize as their principal energy reserve.
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What two compounds make up starch?
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α-amylose
amylopectin |
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What is the structure of amylose?
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Amylose is a linear polymer of glucose linked through α(1-4) bonds.
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What is the structure of amylopectin?
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Amylopectin is a polymer made up of glucose linked through:
- α(1-4) bonds and - α(1-6) branch points |
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How any carbons are on the reducing end of starch?
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1
One Uno |
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Where is Cellulose found?
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The primary structural component of plant cell walls.
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Define the structure of:
Cellulose |
A linear polymer of glucose.
C₁ of one glucose in the β-configuration is linked to C₄ of another glucose. |
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What type of bond cross-links linear polymers of glucose together?
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Hydrogen bonds!
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Define:
Chitin |
The principal structural component of the exoskeletons of invertebrates such as:
crustaceans, bugs, and spiders. Also present in the cell wall of fungi and many algi. |
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What are 5 properties for:
Glycosaminoglycans? |
• Composed of repeating units containing two sugars
• Uronic acid and a hexosamine (sulfate groups) • Heteropolysaccharides • Found in animals • Fill up the extracellular spaces with a gel-like substance (linked to proteins in proteoglycans) |
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What is the structure of Chitin?
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C₁ of N-acetylglucosamine in β-configuration is linked to the C₄ of next residue.
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Proteoglycans are large complexes composed of what 2 molecules?
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glycoproteins
glycosaminoglycans |
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Peptidoglycans are the building blocks of...
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...bacterial cell walls
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Peptidoglycans are formed from chains of...
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...Glycosaminoglycans.
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What are 3 advantages for bacteria having peptidoglycan make up their cell wall?
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1) Provides rigidity
2) Shape 3) Enables bacterium to live in a hypotonic environment (without going *pop*) |
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Define:
Glycoproteins |
Proteins that contain oligosaccharide chains (glycans) covalently attached to their polypeptide side-chains.
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Glycoproteins:
What amino acids function in N-linked and O-linked glycosidic bonds? |
N-linked: Asparagine (Asn)
O-linked: Serine (Ser) or Threonine (Thr) |
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What are 3 reasons for proteins to be glycosylated?
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1) Help define protein structural function
2) Protection 3) Recognition |
