Biological Molecules Quiz

?
  • Created by: Steph
  • Created on: 04-01-13 17:47
How do you test for proteins?
Biuret test- Add a few drops of sodium hydroxide solution, then add some copper(11) sulphate solution. If a protein is present a purple layer forms. If there is not, the solution will stay blue.
1 of 30
How do you test for starch?
Iodine test- add iodine dissolved in potassium iodide solution to the test sample. If starch is present, the sample changes to a blue-black colour.
2 of 30
What do all phospholipids contain?
A glycerol molecule attached to 2 fatty acids and a phosphate molecule
3 of 30
What is the difference between unsaturated and saturated fatty acids?
Unsaturated fatty acids have 2 or more double bonds between the carbon atoms. This causes a kink in the hydrocarbon chain and they are usually liquid at room temperature. Saturated fatty acids have no double bonds, usually solid at room temp
4 of 30
How does a competitive inhibitor work?
It competes for the active site of the enzyme (similar shape as substrate). Blocks active site, forms an inhibitor/enzyme complex, slows down reaction rate.
5 of 30
Name 3 monosaccharides, 3 disaccharides and 3 polysaccharides
Monosaccharides: fructose, glucose, galactose. Disaccharides: maltose, sucrose, lactose. Polysacchardies: starch, glycogen, cellulose.
6 of 30
What four factors affect the rate of enzyme-substrate complexes being formed?
Temperature, pH, enzyme concentration and substrate concentration
7 of 30
When a condensation reaction occurs, joining amino acids, what is the type of bond that forms between them?
Peptide
8 of 30
What is the emulsion test?
Tests for lipids. Shake with ethanol, then add water. Turns solution milky if lipid is present
9 of 30
How can you tell if a reducing sugar is present in a solution?
Add Benedict's reagent to a sample and heat it. If the sample contains reducing sugars it forms a brick red precipitate.
10 of 30
What two polysaccharides form starch?
Amylose and Amylopectin
11 of 30
During a condensation reaction between two monosaccharides, what happens?
A molecule of water is released and a glycosidic bond forms between the two monosaccharides.
12 of 30
What are maltose, sucrose and lactose hydrolysed into?
maltose (glucose and glucose), sucrose (glucose and fructose), lactose (glucose and galactose)
13 of 30
Before doing Benedict's test, what should you do to prepare non-reducing sugars for testing?
Boil the test solution with dilute hydrochloric acid, and then neutralise it with sodium hydrogencarbonate
14 of 30
What are proteins made of?
Long chains of amino acids
15 of 30
What is formed when more than two amino acids join together?
A polypeptide
16 of 30
What is the general structure of an amino acid?
A carboxyl group (-COOH), R group (variable) and an amino group (-NH2) attached to a carbon atom
17 of 30
Name 5 types of proteins
Enzymes, antibodies, transport proteins, structural proteins, hormones
18 of 30
Is the head of a phospholipid hydrophobic or hydrophilic?
Hydrophilic
19 of 30
What are the two types of secondary structure of a protein?
a-helix coil or b-pleated sheet
20 of 30
What is a triglyceride?
It is a glycerol molecule with 3 fatty acids attached to it
21 of 30
What is the type of bond that forms to produce a triglyceride?
Ester bond
22 of 30
What is made of mostly lipids?
Plasma membranes
23 of 30
What do enzymes do to the activation energy of a chemical reaction?
They lower the activation energy, often making reactions happen at a lower temperature than they could without an enzyme. This speeds up the rate of reaction.
24 of 30
Explain the induced fit model
Enzymes are specific and only bond to one particular substrate. A substrate collides with an active site of enzyme and as it binds, the active site changes shape slightly, releases the products and returns to original shape
25 of 30
What is an enzyme's active site shape determined by?
The enzyme's tertiary structure (which is determined by it's primary structure- sequence of amino acids)
26 of 30
What are enzymes known as and why?
Biological catalysts- they speed up chemical reactions
27 of 30
How does pH affect the enzyme activity?
All enzymes have an optimum pH value. Above and below the optimum pH, the H+ and OH- ions can mess up the ionic bonds and hydrogen bonds that hold the tertiary structure in place. This changes the shape of the active site and the enzyme denatures
28 of 30
Why does the active site of an enzyme change shape if the temperature goes above a certain level?
It makes the molecules vibrate more and this vibration breaks some of the bonds that hold the enzyme in shape.
29 of 30
How does a non-competitive inhibitor slow down the enzyme activity?
It binds to the enzyme (away from active site), changing the active site's shape so substrate molecules can't bind to it.
30 of 30

Other cards in this set

Card 2

Front

How do you test for starch?

Back

Iodine test- add iodine dissolved in potassium iodide solution to the test sample. If starch is present, the sample changes to a blue-black colour.

Card 3

Front

What do all phospholipids contain?

Back

Preview of the front of card 3

Card 4

Front

What is the difference between unsaturated and saturated fatty acids?

Back

Preview of the front of card 4

Card 5

Front

How does a competitive inhibitor work?

Back

Preview of the front of card 5
View more cards

Comments

Alice

Report

Thanks, this was a useful test!

Similar Biology resources:

See all Biology resources »See all Biological molecules, organic chemistry and biochemistry resources »