3.3/3.4 Carbohydrates Flashcards
What do carbs contain
Carbon
Hydrogen
Oxygen
What’s a monosaccharide
A single sugar unit
Glucose
Fructose
Ribose
What’s a disaccharide
2 monosaccharides
Lactose
Sucrose
Maltose
What’s a polysaccharide
Polymer of monosaccharides
Glycogen
Cellulose
Starch
What is the formula for glucose
C6 H12 O6
What is glucose
A hexose monosaccharide
Monosaccharide composed of 6 carbons
What are the two variations of glucose
Beta and alpha
When alpha lay next to each other they’re hydroxyl groups can easily react
What bonding will occurs in the condensation reaction between 2 alpha glucose
1,4 glycosidic bond between carbon 1 and carbon 4
Water is formed from the 2 H atoms and 1 O atom
What are the main characteristic of glucose and why is this
They are polar and soluble due to the hydrogen bonds
What are the 3 main feature of starch and glycogen
They are compact
Soluble and branched which makes them efficient storage
How is starch and glycogen formed
Alpha glucose are joined by glycosidic bonds to form polysaccharides
What are the 2 types of starch
Amylose
Amylopectin
What is the structure of amylose
Made form 1,4 glycosidic bonds forming a helix shape that is compact and hydrogen bonds between the structure stabilises it
What is the structure of amylopectin
Made from 1,4 and 1,6 glycosidic bonds giving it a branched structure
What’s the differences between glycogen and starch
Glycogen is the energy store molecule in animals and it forms more branches than starch so is more compact and needs less space to be stored
How do starch and glycogen release the glucose they need for respiration
Through hydrolysis
Addition of water
What are cellulose made of
Beta glucose
How do beta glucose form
One glucose needs to be turned upside down
What is the structure when beta glucose join
A straight chain is created which is called cellulose
It is unable to coil or form branches
What are forms when the chain forms hydrogen bonds
Microfibrils form
These microfibrils join to make macrofibrils and these then combine to make fibres
What are the characteristics of the fibres In cellulose
They are strong and insoluble
So they make cell walls which are hard to break
What is the test used on reducing sugars
What are reducing sugars
Benedicts test
Place sample in boiling tube, add equal volume of benedicts reagent, heat mixture gently in boiling water bath for 5mins
Reducing sugars are monosaccharides and they donate electrons
What is the colour sequence of the benedict test
Blue Green Yellow orange Brick red
What is the test for non reducing sugars
First boil solution with dilute hydrochloric acid then use the benedicts test
You have to hydrolyse the sucrose
What is the test for starch
Iodine test
Yellow brown to purple black
Add a few tops of iodine dissolved in potassium iodid solution mixed with a sample
What price of equipment measures the colour of a liquid
Colorimeter
What do reagent strips do
Test presence of sugars and the concentration of sugar can be determined
