Carbohydrates & Lipids Flashcards
What are monomers?
small identical or similar molecules which can be condensed (joined/linked together) to make larger molecules called polymers
What are polymers?
large molecules made from joining many (3 or more) identical or similar monomers together
How can monomers become polymers?
-monomers are linked into polymers by condensation reactions.
-a condensation reaction joins two monomer units together with the removal of a water molecule which forms a bond
How can polymers become monomers?
-polymers are broken down into monomers by hydrolysis reactions
- a hydrolysis reaction involves the addition of a molecule of water to break the bond between two monomers
What is a condensation reaction?
removing a molecule of water to join two monomers together
What is a hydrolysis reaction?
involves adding a molecule of water to break the bond between two monomers
What is a dimer?
two monosaccharides stuck together
What is a monosaccharide?
a carbohydrate monomer
What is a polysaccharide?
a carbohydrate polymer
If a monomer is a monosaccharide such as alpha/beta glucose, examples of it be?
polysaccharides
What type of bond is formed between two monosaccharides?
glycosidic
Give some examples of monosaccharides
starch, glycogen and cellulose
If amino acid is the monomer, what would the polymer be?
polypeptide or protein
What type of bond is formed between two amino acids?
Peptide Bonds
Give some examples of amino acids
enzymes & haemoglobin
If nucleotides were the monomer, what would the polymer be?
polynucleotide or nucleic acid
What type of bond is formed between two nucleotides?
phosphodiester bonds
What are some examples of nucleotides?
DNA & RNA
Draw an Alpha Glucose Molecule
What is the formula for a carbohydrate?
C6 H12 O6
what elements are found in carbohydrates?
carbon, hydrogen and oxygen
What are some examples of monosaccharides?
glucose, galactose and fructose
What are substances with the same formula but different arrangements called?
isomer(ism)
What is the formula for glucose, galactose and fructose?
C6 H12 O6
How can two monosaccharides join together?
-in a condensation reaction
-forms a disaccharide ( a dimer not a polymer)
-forms a glycosidic bond
What is the basic (simplified) structure of Alpha glucose
What is the equation for a condensation reaction?
C6 H12 O6 + C6 H12 O6 = C12 H22 O11 + H2O
Describe the basic stucture of galactose
Describe the basic structure of fructose
which monosaccharides is maltose made from?
(alpha) glucose + (alpha) glucose
which monosaccharides is lactose made from?
(alpha) glucose + galactose
which monosaccharides is sucrose made from?
(alpha) glucose + fructose
what is the hydrolysis enzyme for maltose?
maltase
what is the hydrolysis enzyme for lactose?
lactase
what is the hydrolysis enzyme for sucrose?
sucrase
what is the equation for 2 monosaccharides?
2 monosaccharides - glycosidic bond= disaccharide+water
what does a hydrolysis reaction do to polysaccharides/ disaccharides?
disaccharide (maltose) =hydrolysis reaction (requires H2O and maltase enzyme) + two monosaccharides (glucose)
what happens during a hydrolysis reaction?
-the removal of one monomer requires one molecule of H2O
-the glycosidic bond is broken
what is a polysaccharide ( and give an example)
a type of polymer formed by joining many monosaccharides together
example-starch
what are the two types of sugars?
monosaccharides and disaccharides
what are the two types of poluysaccharides?
storage and structural
what are the 3 monosaccharides?
glucose, fructose and galactose
what are the three disaccharides?
sucrose, maltose and lactose
what are the storage polysaccharides?
glycogen (human) and starch (plants)
what is the structural polysaccharide?
cellulose
what are the two types of starch?
amylose and amylopectin
describe the features of amylose
-core of starch grain
-coiled=compact
-alpha (1-4) glycosidic bonds
spiral shape
describe the features of amylopectin
-outside of starch grain
-branched chains
-1:4 and 1:6 glycosidic bonds
describe the features of starch
-carbon (1:4) glycosidic bonds so chains of alpha glucose coil into a helix making it compact
-structure is compact so good for storage
-branched chains of alpa glucose with carbon (1:4 and 1:6 glycosidic bonds)
-large surface area for rapid hydrolysis by enzymes to release glucose for respiration
-insoluble so does not affect water potential
-large so does not diffuse out of cells
describe the structure of glycogen
-only found in animal cells
similar to starch however:
-shorter chains
-more highly branched
-larger surface area
-stored in muscles and liver
-shorter chains = more rapidly hydrolysed into glucose used in respiration
-insoluble so doesnt affect water potential
describe the structure of cellulose
-beta glucose molecules join through condensation reactions to form long straight unbranched chains
-every other beta glucose molecule is rotated 180 degrees to allow 1:4 glycosidic bonds to form
-several chains of cellulose are joined together in layers, chains are held by weak H bonds, form microfibrils
Describe the test for reducing sugars
-add equal volume of Benedicts
-heat to 95 degrees celcius
-red/orange/yellow/green precipitate forms
Describe the test for NRS
-complete benedicts test and it should have a negative result/ stay blue
-boil it with an acid then neutralise with an alkali
-brick red precipitate is it is present
Describe how to test a sample of food for the presence of starch
-add potassium iodide solution to the food sample
-blue/black/purple indicates starch is present
Desrcibe the structure of a triglyceride
-1 glycerol and 3 fatty acids
-joined by ester bonds
-in a condensation reaction
Draw a triglyceride
Draw the structure of a glycerol
Draw the structure of a glycerol
Draw the structure of a saturated fatty acid
Draw the structure of an unsaturated fatty acid
Draw the structure of an unsaturated fatty acid
Draw a diagram to show how glycerol and fatty acids turn into triglycerides
Where is the carboxylic acid group (COOH) found in a hydrocarbon chain?
the very left- the first carbon that has a HO and a double bond Oxygen attatched to it
what happens when a glycerol and 3 fatty acids turn into a triglyceride molecule?
-3 ester bonds formed
-3 condensation reactions
-3 water molecules released
what is a saturated fatty acid?
a fatty acid without any double bonds between carbon atoms within the hydrocarbon chain (fully saturated with hydrogens)
what is a polyunsaturated fatty acid?
a fatty acid with multiple double bonds between the carbon atoms within the hydrocarbon chain
what is a monounsaturated fatty acid?
a fatty acid with 1 double bond between the carbon atoms within the hydrocarbon chain
Describe the structure of phospholipids
has a similar structure to triglycerides however one of the fatty acids is replaced by a phosphate group so the glycerol combined with two fatty acids and 1 phospate group
What happens to phospholipids when they are mixed with water?
-form droplet spheres called micelles when mixed with water
-hydrophilic polar heads face the water
-hydrophobic non polar tails face each other
what do the components of a phospholipid do when placed in water?
-phosphate group has a negative charge (polar) whereas the fatty acid has no charge (non polar)
-the head becomes hydrophilic and the fatty acid tails are hydrophobic
-this allows phospholipids to form a bilayer in water
The structure of cellulose is related to it’s role in plant cell walls. explain how (3)
-long, unbranched chains
- of beta glucose
-joined by many weak H bonds
-form microfibrils
-provide strength
Hydrogen bonds are important in cellulose molecules. Explain why (2)
-holds cellulose chains together by forming microfibrils
-provide strength to cell wall
A starch molecule has a spiral shape. explain why the shape is important for its function in cells (1)
compact so good for storage
Explain one way in which the structure of cellulose is linked to its function (2)
long straight unbranched chains provide strength and rigidity
What is an unsaturated fatty acid (2)
a fatty acid with double bonds between the carbons within the hydrocarbon chain
Some seeds contain lipids. Describe how you could use the emulsion test to show that a seed contains lipids (3)
-crush the seeds
-with ethanol
-add water then shake
-forms an emulsion (cloudy)
Describe how the structure of a phospholipid is different to the structure of a triglyceride (2)
-phospholipids have two fatty acids whereas triglycerides have three
-phospholipids have a phosphate group whereas triglycerides do not
Name the type of reaction that would break down carbohydrates into their monomers (1)
hydrolysis
Give three features of starch and explain how each feature enables it to act as a storage substance (3)
-coiled/ helix = tightly packed = stores more
-insoluble= wont gain/lose any substances through osmosis
-branched so the enzyme can break down the starch faster
Describe three differences between the structure of a cellulose and a glycogen molecule (3)
- glycogen is alpha glucose and cellulose is beta glucose
- cellulose has straight chains and glycogen is highly branched
-glycogen has 1:4 and 1:6 glycosidic bonds whereas cellulose only has 1:4 glycosidic bonds
Describe how you would test a piece of food for the presence of a lipid (2)
-crush/grind the food
-add ethanol and an equal volume of water and shake
Compare and contrast the structure and properties of triglycerides and phospholipids (5)
-both contain ester bonds
-both are insoluble
-both contain glycerol and fatty acids
-in both fatty acids may be saturated or unsaturated
-a triglyceride has 1 glycerol and 3 fatty acids whereas a phospholipid has a glycerol, 2 fatty acids and a phosphate group
Describe how lactose is formed and where in the cell it would be attached to a polypeptide to form a glycoprotein
-glucose and galactose
-condensation reaction
-glycosidic bonds
-attached to polypeptide in Golgi
Describe how an ester bond is formed in a phospholipid molecule (2)
-condensation reaction/loss of water
-between a glycerol and a fatty acid
A student carried out the Benedict’s test. Suggest a method other than a colorimeter that this student could use to measure the quantity of reducing sugar in a solution (2)
-filter and dry (the precipitate)
-find the mass/weight
Describe & explain how you could use the Biuret’s test to distinguish a solution of enzyme, lactase, from a solution of lactose (2)
-add Biuret’s to both solutions
-Lactase/enzyme will turn purple/lilac/mauve
Why are lipids not classed as polymers? (3)
-made from fatty acids and glycerol
-not made from identical or similar repeating units
-polymers are 3 or more similar or identical monomers
Describe how an ESTER bond is formed in a phospholipid molecule (2)
-condensation reaction or loss of water
-between OH of glycerol and OH of carboxyl group of fatty acid
Describe the structure of a phospholipid molecule and explain how phospholipids are arranged in a plasma membrane (3)
-Glycerol joined to 2 fatty acids. Phosphate group joined to glycerol on opposite side (joined by condensation reaction with ester bonds)
-Phospholipid has a charged hydrophilic head (phosphate and glycerol) and a non polar hydrophobic tail (fatty acid chains)
-arranged to form a phospholipid bilayer- hydrophilic head faces out towards water and hydrophobic fatty acid chains face in away from water
Describe how a triglyceride molecule is formed [3]
-ONE glycerol molecule and THREE fatty acids
-Condensation reactions AND removal of THREE molecules of water
-Ester bonds are formed.
