Biological molecules

Question 1

Facts

Answer 1

All life on earth share a common chemistry, this provides indirect evidence for evolution.
Despite their great varied, the cells of all living organisms contain only a few groups of carbon based compounds that interact in a similar ways
Our most common component in cells is water

Question 2

Carbohydrates

Answer 2

Proteins form many cell structures
They are also important as are they enzymes, chemical messengers and components of the blood

Question 3

Nucleic Acids

Answer 3

Carry the genetic code for the production of proteins
The genetic code is common to viruses and to all living organisms, providing evidence for evolution

Question 4

Biomolecules

Answer 4

A group of chemicals found in ALL living organisms.
All molecules are made up of atoms

Question 5

Covalent bonds

Answer 5

Atoms share a pair of electrons in their outer shell producing a more stable molecule

Question 6

Ionic bonding

Answer 6

The transfer of electrons result in ions with opposite charges attract each other creating an electrostatic attraction.

Question 7

Hydrogen bonding

Answer 7

Formed when electrons in covalent bonds are unevenly distributed leading to the formation of permanent dipoles
+ dipoles is attracted to lone pair of electrons on an oxygen or nitrogen atoms making a weak electrostatic bond
Collectively these can be very strong

Question 8

Monomers and Polymers

Answer 8

Monomers are small subunits that can be linked together to form long chains called polymers
This happens by polymerisation and makes macromolecules.
Joining monomers to make polymers involve condensation reactions
Breaking down polymers to produce monomers involve a hydrolosis

Question 9

Condensation Reaction

Answer 9

Joins two molecules together with the formation of a chemical bond and involves the elimination of a water molecule.
Bonds the smaller components together into larger molecules

Question 10

Hydrolosis reaction

Answer 10

Breaks a chemical bond between two molecules and involves the use of water
Breaks larger molecules (polymers) into smaller components (monomers)
Smaller molecules can easily diffuse into cells or transported by protein channels

Question 11

Metabolism

Answer 11

Collective name of the chemical processes that takes place in living organisms

Question 12

Solute, solvent and solution

Answer 12

A solute is a substance dissolved in a solvent:
Solute + Solvent = Solution
Solvent= a liquid that has dissolved a substance
Solute= the substance that has dissolved
Solution= the final product after dissolving has happened

Question 13

Carbohydrates

Answer 13

Made up of carbon, water and oxygen
They are sugars (saccharides)
1. Monosaccharides
2. Disaccharides
3. Polysaccharides

Question 14

Monosaccharides

Answer 14

The monomers from which larger carbohydrates form
E.g. glucose, glactose and fructose
Monosaccharides are sweet tasting and soluble
Formula: CH20(3-7)

Question 15

Isomers

Answer 15

Molecules with identical chemical formulas but distinct arrangements

Alpha glucose Beta- Glucose
H H H OH
OH OH HO H

Question 16

Disaccharides

Answer 16

Pairs of monomers join to form a disaccharides
Glucose+glucose=maltose+water
Glucose+fructose=sucrose+water
Glucose+galactose=lactose+water

Question 17

How do disaccharides form

Answer 17

Condensation reaction between two monosaccharides forming a glycosidic bond (water removed)

Question 18

How do Disaccharides split

Answer 18

Hydrolysis reaction breaks the glycosidic bond (addition of water), splitting the disaccharides into two monosaccharides.

Question 19

Polysaccharides

Answer 19

Polymers are formed by condensation reactions between many monomer glucose units
Examples;
Glycogen and starch are formed by condensation of alpha-glucose
Cellulose formed by condensation of Beta-glucose

Question 20

Test for reducing sugars

Answer 20

Test: Benedict’s reagent
Process: Heat liquid sample( water bath for 5 minutes) with Benedict’s
Positive result: blue-red
Due to the reduction of copper(II) sulfate in Benedict’s to form insoluble red precipitate copper(I) oxide

Question 21

Semi- quantatuve test for reducing sugars

Answer 21

Estimates fhe approximate amount of reducing sugar in a sample
Blue= none
Green= very low
Yellow= low
Orange= medium
Brick red= high

Question 22

Examples of monomers

Answer 22

Amino acid, nucleotide, monosaccharide

Question 23

Examples of polymers

Answer 23

Protein, cellulose, starch and glycogen

Question 24

What is the process of adding monomers to a growing chain called and what type of reaction is involved?

Answer 24

Polymerisation and Condensation

Question 25

What is the process of removing monomers from a chain and what type of reaction is involved?

Answer 25

Depolymerisation and Hydrolosis

Question 26

What type of bond do condensation reactions form between two monomers?

Answer 26

Covalent bonds

Question 27

What components are involved in a hydrolysis reaction that releases an amino acid?

Answer 27

Polypeptide and Water

Question 28

Products of condensation reactions

Answer 28

• condensation of amino acids produce proteins
• condensation of two monosaccharides produces disaccharides (many disaccharides form polysaccharides
• condensation of fatty acids and monoglycerides produces lipids

Question 29

Products of hydroloysis

Answer 29

• Hydrolysis of proteins produces amino acids
• Hydrolysis of carbohydrate produces disaccharides and monosaccharides
  (Disaccharides= two monosaccharides joined together)
• Hydrolysis of lipids produces fatty acids and monoglycerides

Question 30

Hydrolysis of proteins

Answer 30

Produces amino acids

Question 31

Hydrolysis of carbohydrate

Answer 31

Produces disaccharides and monosaccharides

Question 32

Hydrolysis of lipids

Answer 32

Produces fatty acids and monoglycerides