intro to carbohydrates and lipids Flashcards
what are the key structures of linear monosaccharides
- hydroxyl group (-OH)
- carbonyl group - aldehyde (-CHO) or ketone (-C=O)
names for number of carbon atoms 3-7
3- triose
4- tetrose
5- pentose
6- hexose
7- heptose
what are reducing sugars
- when carbonyl groups (aldehyde or ketone) can react to gain oxygen
- sugar is oxidised while another compound is reduced
draw the mechanism for a reducing sugar and Benedict reagent
HRC=O + Cu(citrate)2 -2 + Cu2+——> -ORC=O + Cu2O(s)
how do linear monosaccharides go from linear to rings
in an aqueous solution aldehydes or ketones react with hydroxyl on a carbon further along forming a ring structure
what ring structures do aldehyde and ketones produce when forming basic rings
aldehyde + alcohol <—–> hemiacetal
ketone + alcohol <——> hemiketal
what is a chiral carbon
- asymetircial
- 4 different groups attached
- arranged to produced isomers
what is a L isomer of a carbohydrate
-OH on terminal carbon ( second to last) is on the left side
what is a D isomer of a carbohydrate
-OH on terminal carbon (second to last) is on the right side
what is a constitutional isomer
different order of attachment of atoms
what is a sterioisomer
atoms are connected in the same order but differing spacial arrangement
what is an enantiomer
mirror images
what are diastereoisomers
isomers that are not mirror images
what are epimers
differ at one of the several asymmetric carbon atoms
what are anomers
differ at a new asymmetric carbon atom formed on a ring closure
when glucose is in equilibria how many parts of each anomer is present
1/3 - alpha
2/3 - beta
what are the naturally occurring links in disaccharides
1-4, 1-6, 1-2
what are the four common disaccharides and what are they made of
maltose - glucose + glucose
lactose - galactose + glucose
sucrose - fructose + glucose
lactulose - galacose + frucose
what is lactulose used for
osmotic laxative for constipation
how many sugar units are in oligosaccharides
3-10 units
what is the example of trisaccharides and what are they used for
raffinose - skin moisturisers. prebiotics
what is the example of tetrasaccharides and what is it used for
stachyose - bulk sweetener
what are the main functions of oligosaccharides
human breast milk, protein folding, cell signalling, protection
what are the main functions of polysaccharides
protein glycosylation, carbohydrate storage in liver and muscles, extracellular matrix
how many sugar units are found in polysaccharides
<10 units
at room temperature what state are fats and oils in
fats - solid
oils - liquid
what are the properties of lipids
hydrophobic - insoluble in water
dissolve in non polar lipids
what are the polar lipids
- fatty acids
- sterols
- phospholipids
- sphingolipids
what are the non polar lipids
- triacyglcerols
- cholesterol esters
what is the structure of fatty acids
- 12 to 36 carbons - often 16-18
- generally even carbons
- amphipathic - both hydrophobic and hydrophilic
what is the difference between saturated and unsaturated fats
saturated - no double bonds
unsaturated - one double carbon- carbon bond
what is a polyunsaturated fatty acid
more than one double carbon-carbon bond
what are the properties of saturated fats
- low steric hinderance - pack well
- often solid
what are the properties of unsaturated fats
- cis forms predominatly
- pack poorly
- short chains
- often liquids
what fats are liked to heart disease
trans fats
what are the functions of fatty acids
- fuel storage - triglycerides
- membranes - phospholipids and glycolipids
- steroid hormone production
what happens with liver and pancreas disease
- reduced bile acid and lipase release
- impaired lipid breakdown leading to steatorrhoea
what is Zollinger-ellison syndrome
- inactivation of pancreatic lipases
- causes ionisation of bile acids leading to hyperactivity
what happens due to cystic fibrosis to lipid breakdown
- Cl- channels are impaired
- reduces pancreatic lipase secretion
why are fatty acids used as fuel storage
- insoluble
- doesn’t affect intercellular osmotic pressure
what is cholesterols function
- used in steroid hormone production
- it is amphipathic, increases membrane fluidity
- produced in the liver
how are steroid hormones produced
cholesterol —-> preneolone —-> various steroid hormones
