Carbohydrates Flashcards
Functions of carbohydrates
- Supply of carbon for synthesis
- Form structural components (in cells/ tissues)
- Energy storage
- Starch
- Glycogen
- Energy for:
- DNA
- RNA
- ATP
Give the categories of carbohydrate
- Monosaccharides
- Disaccharides (2 monosaccharides)
- Oligosaccharides (3-10 monosaccharides)
- Polysaccharides (10+ monosaccharides)
Give the classifications of monosaccharide
- Triose (3C)
- Tetrose (4C)
- Pentose (5C)
- Hexose* (6C)
*Can form a 5-membered ring
![](https://s3.amazonaws.com/brainscape-prod/system/cm/267/027/712/q_image_thumb.png?1553941283)
Glyceraldehyde
![](https://s3.amazonaws.com/brainscape-prod/system/cm/267/027/926/q_image_thumb.png?1553941313)
Dihydroxyacetone
![](https://s3.amazonaws.com/brainscape-prod/system/cm/267/027/960/q_image_thumb.png?1553941328)
- Ribose
- Deoxyribose
![](https://s3.amazonaws.com/brainscape-prod/system/cm/267/027/972/q_image_thumb.png?1553941340)
Ribulose
![](https://s3.amazonaws.com/brainscape-prod/system/cm/267/028/043/q_image_thumb.png?1553941351)
- Glucose
- Galactose
- Mannose
![](https://s3.amazonaws.com/brainscape-prod/system/cm/267/028/086/q_image_thumb.png?1553941363)
Fructose
Monosaccharide classification is based on…
Functional groups
The functional group of aldoses
Aldehyde group (CHO)
The functional group of ketoses
Ketone group (CO)
Optical rotation: Plane of polarised light rotation
- Right: +
- Left: -
Anomers
- Epimers occurring after cyclization
- Alpha-D-(+)-glucopyranose
- Beta-D-(+)-glucopyranose
- Reflect a change at the:
- Hemiacetal carbon (C1)
- Hemiketal carbon (C1)
Location of -OH group in alpha/beta-D-(+)-glucopyranose
At C1:
- Alpha: Below the ring
- Beta: Above the ring
![](https://s3.amazonaws.com/brainscape-prod/system/cm/267/028/602/a_image_thumb.png?1549462672)
Glucose structure
![](https://s3.amazonaws.com/brainscape-prod/system/cm/267/028/747/a_image_thumb.png?1549462793)
Galactose structure
![](https://s3.amazonaws.com/brainscape-prod/system/cm/267/028/957/a_image_thumb.png?1549462820)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/267/029/010/q_image_thumb.png?1549462842)
Mannose structure
Sugar acids
- Aldehyde at C1 is oxidised to a -COOH group
E.g:
- Gluconic acid
- Glucuronic acid
Aminosugars
- Amino group substitutes for 1 or 2 of the -OH
- The amino group may be acetylated
- Example: Glucosamine
Sugar alcohols
- Lack of an aldehyde/ketone group
- Reduced to alcoholic groups
- E.g:
- Ribitol (by reducing ribose)
- Sorbitol (by reducing glucose)
- Mannitol (by reducing mannose)
- Xylitol (by reducing xylose)
Monosaccharides are bound by a…
Glycosydic bond
Composites of maltose
α-D-glu + α-D-glu
![](https://s3.amazonaws.com/brainscape-prod/system/cm/267/031/260/a_image_thumb.png?1549463833)
(α-1,4 glycosidic bond)
Composites of Cellobiose
β-D-glu + β-D-glu
![](https://s3.amazonaws.com/brainscape-prod/system/cm/267/031/428/a_image_thumb.png?1549463861)
(β-1,4 glycosidic bond)
Composites of Lactose
β-D-gal + β-D-glu
![](https://s3.amazonaws.com/brainscape-prod/system/cm/267/031/440/a_image_thumb.png?1549463887)
(β-1,4 glycosidic bond)
Composites of sucrose
α-D-glu + β-D-fru
![](https://s3.amazonaws.com/brainscape-prod/system/cm/267/031/449/a_image_thumb.png?1549463915)
(α-1, β-2 glycosidic bonds)
Examples of oligosaccharides
Dextrines:
- Amylo-
- Malto-
- Erithro-
- Acro-
Sources of sucrose
- Sugar beet
- Sugar cane
- Sugar maple
Oligosaccharides used in…
- Milk constituents
- Prebiotics - digested by the microbial flora
- Glycolipids/glycoproteins of membranes
Starch and glycogen are examples of…
Homopolysaccharide
Composite of starch
- 20% amylose
- 80% amylopectin
Describe the branching of starch
Branching occurs on the 25th glucose monomer
Glycogen
- Animal storage product
- Branching
- Non-water soluble
- Branching at 8-10th glucose monomer
Glycosidic bonds between monomers are degraded by…
Amylase
Cellulose
- Non water soluble
- Found in plant walls
Describe the bonding of cellulose
- Beta-D-glucose bound by beta 1,4 glycosidic bond
- Hydrogen bonding
![](https://s3.amazonaws.com/brainscape-prod/system/cm/267/124/120/a_image_thumb.png?1549538722)
How is cellulose degraded by herbivores?
Presence of bacterial cellulase in the rumen
Examples of heteropolysaccharides
- Hyaluronic acid
- Chondroitin sulphate
- Heparin
Contain beta 1,3 glycosidic bond
Hyaluronic acid composition
Repeating monomers:
- D-glucuronate
- N-acetyl-D-glucosamine
![](https://s3.amazonaws.com/brainscape-prod/system/cm/267/124/316/a_image_thumb.png?1549539341)
Hyaluronic acid is degraded by…
Hyaluronidase
Where is hyaluronidase found?
In the coat of the ovum
Chondroitin sulphate composition
Alternating units:
- D-glucuronate
- N-acetyl-D-galactosamine
Vitamin A has a role in the binding of the sulphate group
![](https://s3.amazonaws.com/brainscape-prod/system/cm/267/124/569/a_image_thumb.png?1549540037)
Where is chondroitin sulphate found?
- Cartilage
- Bone
Heparin composition
Repeating units:
- D-glucuronate
- D-glucosamine
- Has an extended helical conformation*
- Known as a clearing factor*
![](https://s3.amazonaws.com/brainscape-prod/system/cm/267/124/875/a_image_thumb.png?1549540003)
The carbohydrate portion of glycoproteins differs from that of glycosaminoglycans in that it is…
- Shorter
- Often branched
Cori cycle
- Synthesis of glucose-6-phosphate via gluconeogenesis
- Glucose-6-phosphate → Glucose
Anaerobic substrate for gluconeogenesis
Lactate
Glycogenesis (GG)
- Synthesis of glycogen from glucose
- Liver, muscle cytoplasm