Topic 1 - Saccharides + Triglycerides 1.12 To 1.16 Flashcards
What are monosaccharides
The monomers of carbohydrates (sugars)
They form glycosidic bonds with each other to form polysaccharides
What is a hexose monosaccharide
A monosaccharide containing 6 carbons.
It has the formula
C6 H12 O6
What is the difference between alpha glucose and beta glucose (structure)
In alpha Glucose the H group is above Carbon 1 and the OH is below C1
In beta glucose the OH group is above C1 and the H group is below C1
What is the only structural difference between beta glucose and galactose
In beta glucose the H group is above C4 and the OH group is below
In galactose the OH group is above C4 and the H group is below
How is the structure of Fructose different from glucose and galactose
Fructose contains two CH2 OH groups
Because of this it has a pentagonal structure (but is still a hexose sugar)
What are glucose, fructose and galactose
They are monosaccharides
They are hexose sugars
What is a disaccharide
The molecule formed when two monosaccharides form glycosidic bons with each other
What type of reaction makes disaccharides / polysaccharides
Condensation reactions
How much water is produced when two hexose monosaccharides form a disaccharide
1 H20
What is the formula of a disaccharide formed by hexose monosaccharides
C12 H22 O 11
(C6 H12 O6 ×2) - ( 1 H20)
What is maltose
A disaccharide formed when two alpha glucose molecules form an alpha 1-4 glycosidic bond
Where is maltose found biologically / used
It is found in germinating seeds and used for brewing
What bond is present in maltose (between the monosaccharides)
An alpha 1-4 glycosidic bond
What is sucrose
A disaccharide made of alpha glucose and fructose
An alpha 1-2 glycosidic bond is formed
What the biological role of sucrose and what do we use it for
It is used to transport energy in plants
We use it in cooking
It is stored in sugar cane
What bond is formed between the monosaccharides in sucrose
An alpha 1-2 glycosidic bond
What is lactose
A disaccharide formed by alpha glucose and galactose
There is a beta 1-4 glycosidic bond between the monosaccharides
What is the biological role of lactose and what do we use it for
It is found in mammalian milk to supply energy
We use it in food (e.g cheese)
What bond is formed between the monosaccharides in lactose
A beta 1-4 glycosidic bond
How is it determined whether a glycosidic bond is alpha or beta
If the OH groups on C1 and C4 are both below or both above the carbon, and alpha bond will form
If one is above and one is below a beta bond will form
How are Disaccharides broken down
In hydrolysis reactions ( 1 H2O is added)
When do humans break down disaccharides
They are broken down during digestion
(In reactions catalysed by enzymes)
What is glycogen
A highly branched, not coiled polysaccharide found in animals and fungi
It is made by alpha glucose monosaccharides forming 1-4 glycosidic bonds
(And 1-6 glycosidic bonds every 10 units)
Why is glycogen highly branched
Having many branches means that there are many terminal ends for enzymes to join to
This means glycogen can be quickly broken down (which is needed to maintain a high metabolic rate)
What is glycogen used for
Glycogen is used to store energy
As it is compact it can store a lot of energy in a small space
What is glycogen used for
Glycogen is used to store energy
As it is compact it can store a lot of energy in a small space
Where is the energy in polysaccharides (such as glycogen) stored / located
In the glycosidic bonds between monosaccharides
What is starch
A polysaccharide found in plants that is used to store energy
It is made of two types - amylose and amylopectin
What is amylose
A type of starch
It is unbranched, linear and coiled in a helix
It contains alpha 1-4 glycosidic bonds between alpha glucose molecules
What is amylopectin
A type of starch
It is branched (every 20 minutes) and not coiled
There are alpha 1-4 and 1-6 glycosidic bonds between alpha glucose
Why does amylopectin have less branches than glycogen
As plants have a lower metabolic rate
Why are starch and glycogen suitable storage molecules
Glycogen + amylopectin are branched, so they can be hydrolysed easily (quick energy release)
They are compact → store a lot of energy.
They are large → do not cross surface membranes
They are insoluble → They do not dissolve in water, so they have no osmotic effect
What is cellulose
It is a linear and unbranched polysaccharide used structurally in plants
It is made from 1-4 glycosidic bonds between beta glucose
Several cellulose fibers form hydrogen bonds between each other
What is the purpose of cellulose
Cellulose is used structurally, and it can be found most commonly in plant cell walls.
Where are triglycerides found
in fats and oils
What is a triglyceride made of
Glycerol and 3 fatty acids
There is an ester bond between the glycerol and each fatty acid
What reaction forms triglycerides
Condensation reactions - 3 water is produced
How are triglycerides broken down
In hydrolysis ( 3 water is added)
what are saturated fats
Fats made of triglycerides that contain (saturated) fatty acids with a c-c bonds
Why are saturated fats solid at room temperature
The fatty acids are linear and unbranched so the triglycerides can pack closer together
This makes the intermolecular forces between the triglycerides harder to break so they are solid at room temperature
What are unsaturated fats
Fats which contain unsaturated fatty acids with a C=C double bond
This means that they have bends (or kinks) in their Carbon chain
Why are unsaturated fatty acids liquid at room temperature
Due to the kinks in the carbon chains the trigkycerides do not pack closely together.
This means the intermolecular forces between them are weaker, and require less energy to break
Why does the hydrolysis of triglycerides decrease the pH of a solution
As fatty acids are acidic
Hydrolysis of triglycerides releases fatty acids into the solution, causing the pH to decreases
How do beta glucose molecules form alpha 1-4 glycosidic bonds
The molecules inverts after every bond is formed. This ensures the OH groups are always in the same position
Whats the minimum number of monosaccharides needed to make a polysaccharide
10
Why is starch made from amylose + amylopectin
Amylose can be less readily hydrolysed, but can be stored more compactly than amylopectin as it has a helical structure
Why is cellulose unable to spiralise
As hydrogen bonds hold molecules of cellulose together
