Macronutrients - carbohydrates Flashcards
what type of compounds are macronutrients?
organic compounds
what are organic compounds?
means they contain a carbon chain joined to atoms of hydrogen and oxygen
what do carbohydrates act as?
- building blocks for more complex molecules eg ribose
- sources of energy
- energy stores
- structural support
What are the three main groups of carbohydrates?
- monosaccharides
- disaccharides
- polysaccharides
triose is a monosaccharide, what is it’s biological role?
important in metabolism, intermediates in the reactions of respiration and photosynthesis
pentose is a monosaccharide, what is its biological role?
constituent of nucleotides eg deoxyribose in DNA and ribose in RNA
What do all hexose sugars have?
6 carbons
what are three examples of hexose sugars?
glucose
fructose
galactose
What are glucose, fructose and galactose and what does the difference do?
isomers, small differences effect taste and digestibility
what are isomers?
molecules with the same chemical formula but different arrangement of atoms
what is glucose’s biological role?
starting material for respiration, and building block of glycogen and other polypeptides
what are glucose’s two isomers?
alpha and beta
draw an alpha glucose and a beta glucose and state the difference between them
( difference is the hydrogen and hydroxyl group have been switched )
What are disaccharides?
formed by joining two monosaccharides together and forming a glycosidic bond and losing water (condesnsation reaction)
what makes up maltose? draw the reaction
alpha glucose + alpha glucose -> maltose + water
what are the component monosaccharides in maltose and what is its biological role?
glucose + glucose, in germinating seeds
what are the component monosaccharides in sucrose and what is its biological role?
glucose and fructose
transport in phloem of flowering plants
what are the component monosaccharides of lactose and was its biological role?
glucose and galactose, in mammalian milk
what is a polysaccharide?
many monosaccharides joined together
what are the 2 main groups of polysaccharides? give two examples
- storage polysaccharides (eg starch - plants - and glycogen - animals- )
- structural polysaccharides (eg cellulose - plant cell walls- and chitin -exoskeletons of orthopods- )
what are four properties that make storage polysaccharides good storage compounds?
- unable to diffuse out of cell
- insoluble in water, no osmatic effect
- compact
- easily hydrolysed
what type of glucose are starch and glycogen made up of?
only alpha glucose
describe the properties of amylose
-unbranched polymer joined by 1-4 glycosidic bonds
-glucose released by glycosidic bond
-enzyme action at both ends of the polymer (hydrolysed slower)
describe the properties of amylopectin
branched polymer
glucose released by enzyme action at all endings
joined by a 1-6 glycosidic bond
what are some similarities between amylose and amylopectin?
- both have only alpha glucose monomers
- both store glucose
- both release glucose
- both formed in plants
what are some differences between amylose and amylopectin?
- amylose has a helix form however amylopectin has a helix form with smaller helixes branched off sides
- amylose is an unbranched polymer amylopectin is branched
- amylose has a slower release of glucose
How is glycogen similar to amylopectin?
same subunits but far more branched and therefore more concentrated
where is glycogen stored in animals?
stored in the liver and muscles
when is glycogen quickly hydrolised?
when an energy supply is needed
what are some properties of cellulose?
a main structural sugar in plants
permeable to numerous substances
about 33% of plant matter
most common organic compound on earth
made up of beta glucose
how are cellulose monomers able to form a glycosidic bond?
by the structure turning through 180 degrees so the OH-ions are lined up
how do beta glucose form hydrogen bonds?
they do not have a helix shape and instead lie flat close together, therefore being able to form hydrogen bonds throughout
why do beta glucose monomers lie flat?
b/c they have rotated throuh 180 degrees so the polymer doesn’t form a helix and instead lies flat
How are crosslinks formed?
by each cellulose chain forming hydrogen bonds with parallel cellulose chains
How are micro-fibrilis formed?
60-70 tightly cross-linked cellulose molecules form micro-fibrilis
What are the bundles in which micro-fibrilis is held?
fibres
why can’t humans digest cellulose?
we don’t produce cellulase
what is chitin made from?
form beta glucose monomers
how is chitin structurally similar to cellulose?
beta glucose, 1-4 glycosidic bonds and 180 degree rotations
how is chitin different from cellulose?
one hydroxide group on each monomer has been replaced with one amine group
what are some properties of chitin?
strong, waterproof and lightweight
draw an alpha glucose
draw a beta glucose
draw the formation of maltose (alpha glucose + alpha glucose)
draw an amylose
draw an amylopectin
draw a cellulose structure
draw a chitin structure
