carbohydrates Flashcards
what are the monomers that make up carbohydrates?
monosaccharides
what are the monosaccharides? [5]
are they hexose or pentose?
hexose (6C)
• alpha glucose
• beta glucose
• fructose
• galactose
pentose (5C)
• ribose
what are the chemical elements that make carbohydrates?
C H O
structure of alpha and beta glucose.
what’s the difference?
use text book pg 46
Hydroxyl group is at the top in b glucose
what’s the structure of ribose?
revision guide pg 22
what is a disaccharide ?
what is a polysaccharide?
2 monosaccharides joined together
2+ monosaccharides joined together
what’s the name of the bond that hounds monosaccharides together?
glycosidic
(type of covalent)
what reaction bonds 2 monosaccharides together and how?
condensation
- the bond of H + OH from the 2 monosaccharides are broken > forming a molecule of water
- the monomers form a glycosidic bond between C1 and C4
=disaccharide
what the named disaccharides?
what monosaccharides join for these to form?
• sucrose -> a glucose + fructose
• lactose -> a glucose + b glucose
• maltose -> a glucose + a glucose
how are the bonds broken apart?
when does this usually happen?
hydrolysis
adding a molecule of water to break glycosidic bond
when needed for respiration
what are the named polysaccharides? [4]
starch:
1) amylose
2) amylopectin
3) glycogen
4) cellulose
what monosaccharides with what bond form starch? [2]
amylose - a glucose, 1-4 glycosidic bonds
amylopectin - a glucose, 1-4 glycosis bond, some 1-6 bonds
what monosaccharides with what bond forms cellulose? how?
b glucose- one glucose flips to form 1-4 glycosidic bonds
what monosaccharides with what bond forms glycogen?
a glucose- 1-4 and 1-6 glycosidic bonds
what’s the structure of each polysaccharide? [4]
amylose- long, helix
amylopectin- branched
glycogen- very branched
cellulose- straight, unbranched
what’s the properties of starch, ref storage? link to structure [3]
1) insoluble- water cant enter cells by osmosis, which would make them swell. good for storage.
2) flexible
3) unreactive
AMYLOSE
1)compact, good for storage:
from helix structure, due to the angles of glycosidic bonds (1-4)
AMYLOPECTIN
2)enzymes can break down glycosidic bonds quickly for so glucose can be realised respiration:
from branches
what is starch?
main energy storage material in plants:
cells get energy from glucose, plants store excess glucose as starch so can be broken down for energy
what is glycogen?
main energy storage material in animals:
excess glucose stored as glycogen, can be broken down for energy
what are the properties of glycogen, reference to storage? link back to structure [4]
idea for storage:
1)insoluble, no effect on water potential
2)enzymes can quickly break down so glucose can be released quickly for energy:
from branches
3)compact, store large amounts of energy
4)compact, good for storage:
from branches
what are the properties of cellulose? link back to structure
microfibrils- form by hydrogen bonds between cellulose
microfibrils join making macrofibrils
macrofibrils join making fibres
fibres- strong + insoluble, structural support to make cell walls (plants)
what are the sugars [5]
• glucose a + b
• fructose
• sucrose
• lactose
• galactose
aka monosaccharides + disaccharides
which ion is required for the hydrolysis of starch by an enzyme?
Cl-
what’s the most soluble carbohydrate?
what’s the least soluble carbohydrate?
most soluble - glucose
least soluble - amylopectin
what can make carbohydrates soluble?
(-OH) hydroxyl group is polar, so the more free hydroxyl groups the more soluble
