Carbohydrates Flashcards
What are the compounds of carbohydrates?
Carbon
Hydrogen
Oxygen
What’s the generic formula for carbohydrates?
CnH2nOn
What are the three functions of carbs?
Source of energy
Store of energy
Structural support
What are the three main types of carbohydrates
Monosaccharides
Disaccharides
Polysaccharides
Monosaccharides
Simplest forms of carbohydrates that are used as building blocks for more complex carbohydrates.
Trioses
Number of carbon atoms
Involved in…
3 carbon atoms
Metabolic reactions
Pentoses
Number of carbons
Formation of…
5 carbon atoms
Nucleic acid DNA/RNA
Hexoses
Number of carbon atoms
Main source of…
6 carbon atoms e.g glucose
Energy
Definition of Isomerism
Two molecules that have the same chemical formula but they have different structural formulas.
What is different in alpha glucose to beta glucose?
In alpha glucose the hydroxyl group (OH) is underneath C1.
Where is the hydroxyl group in the beta glucose?
Above carbon atom 1
What acronym is used to remember the difference between alpha and beta glucose?
A Alpha
B Below
B Beta
A Above
What are the two properties of monosaccharides?
Soluble
Sweet tasting
Explain the role of monosaccharides as an energy source in respiration.
GLUCOSE
C-H bonds and C-C bonds are broken: release energy
Energy transferred to make ATP
ATP is the energy currency of the cell
Monosaccharides as building blocks
To make larger molecules e.g glucose to make starch, glycogen and cellulose
As intermediates in reactions
Trioses - intermediates in respiration and photosynthesis reactions
Constituents of nucleotides
e.g deoxyribose in DNA, ribose in RNA, ATP and ADP
What is removed during â Condensation Reaction?
H2O Water
What is Hydrolysis?
Chemical addition of water to break bonds
Breaks a disaccharide into 2 monosaccharide
Between which two carbon atoms does a glycosidic bond form?
1 and 4
What bond forms between two monosaccharides and define it.
Glycosidic - two carbon atoms end up sharing an oxygen atom
What is formed when two monosaccharide bond together?
Disaccharide
Name the 3 disaccharides you must learn
Sucrose
Lactose
Maltose
What are the monosaccharide units of Sucrose
Glucose + Fructose
What monosaccharides form lactose
Glucose + Galactose
What monosaccharides form maltose
Glucose + Glucose
What does Benedict’s test for
Reducing sugars in solutions
What must you remember to do in a Benedcit’s test?
Heat the solution in a water bath
What will happen to the solution if a reducing sugar is present in a solution
From blue to green, yellow, orange and finally brick red
The colour of the precipitate depends upon the concentration of the reducing sugar
Definition of polymer
A large molecule comprising repeated units, monomers, bonded together.
What reaction takes place to turn monomers into polymers
Polymerisation
Polysaccharides
Polymers made up of hundreds of monosaccharide units
4 examples of polysaccharides
Starch
Glycogen
Cellulose
Chitin
What reaction take place in the formation of polysaccharides
Condensation where water is lost
Are polysaccharides sweet tasting?
No, they’re not sugars
What is the reverse reaction of a condensation reaction?
Hydrolysis- chemical addition of water
What molecules is starch made up of?
Alpha glucose
What two polymers form starch?
Amylose and Amylopectin
What type of molecule is starch?
Polysaccharide
Is starch soluble or insoluble?
Insoluble
What solution detects the presence of starch?
Iodine
What colour change is seen if starch is present and tested with iodine?
From brown-orange to blue-black
Describe Amylose
A linear, unbranched polymer with alpha1-4 glycosidic bonds
What describes the shape of amylose
Alpha-helix
Describe Amylopectin
Chains of glucose monomers joined with alpha1-4 glycosidic bonds, cross linked with alpha1-6 bonds
Describe the properties of starch
Hydrolyses quickly
No osmotic effect
What is glycogen’s function
Main storage product in animals
Muscles and liver
What is glycogen similar to
Amylopectin
What bonds are present in glycogen?
Alpha1-4 and Alpha1-6 glycosidic bonds
What’s the difference between glycogen and amylopectin?
Glycogen have shorter alpha1-4 linked chain and therefore more branched
the type of reaction that occurs when a disaccharide is formed from two monosaccharides is
condensation
the type of bond that forms when a disaccharide is formed from two monosaccharides is called
glycosidic bond
the products of hydrolysis of lactose are
alpha-glucose and alpha-glucose
starch is a polymer made from which monomer
alpha-glucose
the most important carbohydrate fuel in human cells is
glucose
saccharides contain the following combination of elements
carbon, hydrogen
what type of carbohydrate is cellulose? (storage/structural)
structural polysaccharide
what monosaccharide makes up cellulose?
beta-glucose
what bonds and characteristics are present in cellulose?
1,4 glycosidic bonds forming long, unbranched chains
hydrogen bonds in the microfibril
what is the purpose of microfibrils?
strength
describe microfibrils
adjacent glucose molecules are rotated 180*
what bonds are present in the microfibrils of cellulose?
hydrogen bonds
what type of polysaccharide is chitin?
structural
what is the monomer of chitin?
beta-glucose
list 2 of chitin’s functions
exoskeleton of insects
fungal cell wall
describe what is meant by GLUCOSAMINE in chitin
amino acid side chains - the amino acid group which has reacted with beta-glucose
describe the 3 similarities between chitin and cellulose
-long chains of beta-glucose 1,4 linked monomers
-monomers rotated 180* in relation to neighbour
-long parallel chains are cross linked by hydrogen binds
what’s one difference between the groups in chitin and cellulose?
chitin has groups derived from amino acids
Why does amylose coil up?
more compact within cell walls. hydrogen bonds. no osmotic effect on cells
what are the 3 functions of carbohydrates?
source of energy, sores energy, structural support
What are three main types of carbohydrates?
monosaccharides, disaccharides, polysaccharides
list two examples of pentose sugars
Ribose, Dioxiribose
What is the difference between alpha-glucose and beta-glucose?
The location of the hydroxyl group in the structural formula. alpha the OH is beneath, beta the OH is above the carbon atom 1.
