Biological Molecules Flashcards
Define MONOMERS with examples
Monomers are smaller units from which larger molecules are made. Examples of monomers include:
Monosaccharides
Nucleic acids
Amino acids
Define POLYMERS
Polymers are chemical molecules, made from monomers, joined together in a, specific/repeating pattern
What is the reaction involved to make monomers into polymers?
(One word answer)
Condensation reaction
What is the name of the reaction involved to make polymers into monomers?
Hydrolysis
Define condensation reaction [3 marks]
A condensation reaction joins two molecules together(monomers)[1]with the formation of a chemical bond [1] and removal of water[1]
Define hydrolysis [2 marks]
A hydrolysis reaction breaks the chemical bond between two molecules [1] with the use of water[1]
Molecule with the same structure BUT with different atoms connected is known as _______
Isomers
Carbohydrates are _________ whose monomers are called _________.
Carbohydrates contain__,__,__
Monosaccharides are joined together by a ________ _______
What kind of bond is made when two monomers are joined together by a condensation reaction releasing water?
What is it made when two monosaccharides are joined together!
Polymers
Monosaccharide
C,H,O
Condensation Reaction
Glycosidic bond
Disaccharide
Glucose is a monosaccharide with six carbon atoms in each molecule. This is called__________
Define the two types of glucose!
You need to know the structures of both the α-glucose and β-glucose. Draw the structures of both isomers.
Hexose sugar
Alpha glucose and Beta glucose
Write the three equations that you must remember for your exam: [two alpha glucose make______]
Glucose + glucose make Maltose
Glucose + Fructose make Sucrose
Glucose + galactose make Lactose
Sugar is the general term for ___________ and __________.
All sugars can be classified as _______ or _________
What test is used to test for sugars?
Reducing sugars include all ______
Monosaccharides and disaccharides
Reducing or non-reducing sugars!
The test is known as Benedict’s Test
All monosaccharide and LACTOSE+FRUCTOSE
Describe the test for reducing sugars. What will happened if the results are positive. And state ALL the colours for a positive result.
Add the benedict’s reagent solution to a sample
HEAT it in a water bath that’s been brought to the BOIL
If the test is positive a solid precipitate would be formed
The colour of the precipitate changes from;
Blue
Green
Yellow
Orange
Red brick
Describe the test for a NON-REDUCING sugar. State the steps and the colours for a positive result.
First, carry out the test with the Benedict reagent as normal to see the negative result.
BREAK them down into MONOSACCHARIDES(HOW DO YOU DO THIS?)
DO THIS BY GETTING A SAMPLE AND ADDING dilute hydrochloric acid
Then carefully boil the sample
Then neutralise it with sodium hydrogen carbonate
Then just carry the benedict’s test as usual with the reducing sugars and heat!
If it’s negative, the solution would stay blue, meaning there is no type of sugar present
What is a more ACCURATE way to do this experiment?
A more accurate way of doing this is to filter the solution and then weigh the precipitate
Describe the test for the presence of starch
To test the presence of starch, add iodine solution
to the sample. If the result is positive, then the colour would change from orange/brown to blues/black
Glycogen and starch are made by a __________ reaction of _ glucose
________ is made by a _ glucose
Condensation reaction, alpha glucose
Cellulose, beta glucose
What is the main energy store in plants and animals.
What is cellulose?
Starch in plants and glycogen in animals.
Cellulose is the major component
of cell walls in plants
Define amylose in detail
It is a long, unbranched chain of alpha glucose molecules joined together by a condensation reaction. The angles of the glycosidic bonds give it a coiled structure. This makes it compact so you can store a lot of glucose.
It’s also insoluble therefore it will not affect the water potential of the cells through osmosis and cannot leave the cell MEMBRANE as it is relatively large
Define amylopectin in detail
Long, branched chain of alpha glucose molecules joined together by a condensation reaction with (1,4) and (1,6) glycosidic bonds. The side branches allow the enzymes to break down the molecules and get to the glycosidic bonds quickly to release glucose. It’s also insoluble and large, so it doesn’t affect the water potential of the cell and can’t leave the cell membrane.
Define starch in detail
Starch is insoluble therefore it does not affect the water potential of the cell through osmosis. It’s large and cannot leave the cell membrane.
GLYCOGEN is…
Excess glucose is stored as glycogen in the liver and other muscle cells of the body. Its structure is very similar to amylopectinso it has (1,4) and (1,6) glycosidic bonds, except that it has LOADS more SIDE BRANCHES. Loads of side branches will allowstored glucose to be releasedquickly, which is important. It’s also very COMPACT molecule so really good for storage. It is insoluble so it does not affect the water potential of the cell by osmosis.
Define cellulose in detail.
Cellulose is made of LONG, UNBRANCHED chains of BETA glucose. When beta glucose molecules bond, they form STRAIGHT cellulose chains. Those cellulose chains are linked together by HYDROGEN BONDS to form strong fibres called MICROFIBRILS. Microfibrils provide STRUCTURAL SUPPORT for cells in plants
Define the two types of lipids that you are required to know for the AQA exam
Triglycerides and phospholipids