Carbs and Lipids Flashcards
What are the 5 main biological molecules that make up living organisms?
Lipids
Carbohydrates
Proteins
DNA
Water
What is a monomer?
An individual repeating unit that makes a polymer
What is a polymer?
Many regular, repeating units of monomers
Give two examples of monomers:
Monosaccharides, amino acids and nucleotides
What is a monosaccharide?
The monomer from which polysaccharides are made. They are carbohydrates
What is a disaccharide?
2 monosaccharides joined together
What is a polysaccharide?
3 or more monosaccharides joined together
What type of reaction is used to join monomers together?
Condensation reaction
What is a condensation reaction?
A reaction that joins two molecules together with the formation of a chemical bond and the elimination of a molecule of water.
What does the suffix “-lysis” mean?
To split
What type of reaction is used to separate disaccharides or polysaccharides?
Hydrolysis
What is a hydrolysis reaction?
A reaction that breaks a chemical bond between two molecules and involves the use of a water molecule.
Which reaction gives out a water molecule, condensation or hydrolysis?
Condensation
Which reaction requires a water molecule, condensation or hydrolysis?
Hydrolysis
What are the four monosaccharides you need to know?
α-glucose
β-glucose
Galactose
Fructose
What are the three disaccharides you need to know?
Maltose
Lactose
Sucrose
What are the three polysaccharides you need to know?
Starch
Glycogen
Cellulose
Which two monosaccharides make Maltose?
α-glucose + α-glucose
Which two monosaccharides make Lactose?
α-glucose + galactose
Which two monosaccharides make Sucrose?
α-glucose + fructose
What monosaccharide makes up starch?
α-glucose
What monosaccharide makes up glycogen?
α-glucose
What monosaccharide makes up cellulose?
β-glucose
Draw the simplified structure of α-glucose
Draw the simplified structure of β-glucose
Draw the simplified structure of galactose
What is the formula for alpha glucose, beta glucose and galactose?
C6H12O6
What are isomers?
Compounds that have the same molecular formula but are structurally different
What type of bond does a condensation reaction between two α-glucose make?
α 1,4 glycosidic bond
How are polysaccharides formed?
Polysaccharides are formed by combining many monosaccharides via condensation reaction
What is starch?
A polysaccharide of glucose joined via condensation reactions, to form glycosidic bonds
What type of glycosidic bonds do starch molecules have?
α 1,4 and α 1,6 bonds
Describe the structure of starch/glycogen and explain how it aids its function
It’s
- Large so it won’t diffuse out of a cell
- Insoluble so osmotically inactive
- Alpha helix shape so its a compact energy store
- Branched so it an rapidly release alpha glucose when needed
What is glycogen?
A polysaccharide of many alpha glucose joined via condensation reactions to form glycosidic bonds
What is the difference between starch and glycogen?
Glycogen is much bigger, contains more 1,6 bonds and is much more branched because it’s used in animals which require much more energy for cell activity
Where and in what form is starch found in?
In plant cells in the form of grain
Where and in what form is glycogen found?
In granules in the cytoplasm of animal cells
What is cellulose?
A polysaccharide of many β-glucose molecules joined through condensation reactions to form β 1,4 glycosidic bonds
What is cellulose used for?
Building cell walls
What is special about the formation of β-glucose molecules in cellulose?
Every other molecule is inverted
Why is cellulose arranged the way it is?
Because if they were left the right way up next to each other, there would be no oxygen left to form a glycosidic bond and so the molecule couldn’t be condensed
Describe the structure of cellulose and how its aids function
- Made from beta glucose which allows long straight chains to form
- Parallel chains for hydrogen bond crosslinks which adds strength to cell walls
- Cellulose can form micro fibrils which join to form fibres which adds strength
What is a reducing sugar?
One that is able to lose an electron and give it to another compound (reduce it)
How do we test for reducing sugars?
- Add Benedict’s solution to the sample
- Heat the solution
- Colour change from Blue to Green, Yellow, Orange or Red means a positive result
Why does a colour change occur when you add a reducing sugar to Benedict’s?
Benedict’s solution contains Cu2+ ions in the form of blue Copper (II) Sulphate. When When copper sulphate is reduced it becomes red Copper (I) Oxide
What type of data is the results from the test for reducing sugars?
Semi-quantitative. It gives an idea of concentration but not an exact value
How do you test for non reducing sugars?
- Following a negative Benedict’s test
- Boil the sample with HCl to hydrolyse the non reducing sugar
- Cool, then neutralise using NaOH
- Add Benedict’s
- Heat
- Colour change from Blue to Red
Why do you need to boil non reducing sugars before testing for them?
To hydrolyse them into reducing monosaccharides in order to get a colour change and prove that there was a sugar present
How do you test for starch?
- Add iodine to the sample
- Orange to Blue Black is a positive result
What can lipids be used for?
- Storing Energy
- Insulation (Thermal and Electrical) e.g. myelin sheets cover nerves
- Waterproofing, in the form of a waxy cuticle on leaves
- Protection (heart and kidneys)
What are the two types of lipids?
- Triglycerides
- Phospholipids
What is the difference between saturated and unsaturated fats?
The presence of a C=C double bond
What is the difference between fats and oils?
Fats are lipids that are solid at room temperature and oils are lipids that are liquid at room temperature.
What type of bond occurs between glycerol and fatty acids?
Ester bond
Describe the structure of triglycerides and explain how it aids its function
- Insoluble so osmotically inactive
- Low mass to energy ratio so you don’t have to carry a heavy energy store
- High ratio of H atoms to O atoms so water can be released during break down
- High ratio of energy storing C – H bonds so its an energy dense molecule
Which 4 molecules make up a phospholipid?
Phosphate, Glycerol, 2 Fatty Acids
Which region of a phospholipid is hydrophobic?
The tail
Which region of a phospholipid is hydrophilic?
The head
Describe the structure of phospholipids and explain how it aids function.
- Hydrophobic and hydrophilic regions (amphipathic) which allows phospholipid bilayer to form
- Glycolipids can form which allows for cell recognition.
What is the test for lipids?
- Add ethanol to the sample
- Shake
- Add to distilled water
- White milky emulsion forms if positive
What type of reaction joins monomers together?
condensation
What type of reaction breaks polymers into their monomers?
hydrolysis
What type of bond joins glycerol and fatty acids?
Ester bond
