Biomolecules

Question 1

Describe the structure of a water molecule

Answer 1

• One oxygen atom covalently bonded by two hydrogen atoms
  -Oxygen is more electronegative than hydrogen, which leads to polar bonds and an uneven charge distribution

Question 2

What is a hydrogen bond?

Answer 2

A type of strong intermolecular force. Hydrogen atoms which are directly covalently bonded to a highly electronegative atom (O, N or F) are attracted to highly electronegative atoms in other molecules.

Question 3

What is a solvent?

Answer 3

Any substance which solutes can dissolve in to form a solution

Question 4

State 6 important properties of water

Answer 4

-Acts as a solvent
-Acts as a metabolite
-High surface tension
-High specific heat capacity
-High latent heat of vaporization
-Strong cohesion and adhesion forces

Question 5

Why is cohesion useful in biological systems?

Answer 5

It’s the main force supporting columns of water as they are pulled up the xylem in plants. The water molecules stick together as a constant column.

Question 6

Why is adhesion useful in biological systems?

Answer 6

It allows water to move up the xylem against the pull of gravity.

Question 7

What are carbohydrates?

Answer 7

Molecules that consist of carbon, hydrogen and oxygen only.

Question 8

What are monosaccharides?

Answer 8

One individual monomeric sugar unit

Question 9

What is a disaccharide?

Answer 9

Two monosaccharides covalently linked by a glycosidic bond.

Question 10

What is a polysaccharide?

Answer 10

A polymer made of many monosaccharides covalently linked by glycosidic bonds.

Question 11

What is a glycosidic bond?

Answer 11

A type of bond that joins a monosaccharide to another molecule (usually another monosaccharide).

Question 12

What type of reaction forms a glycosidic bond?

Answer 12

A condensation reaction

Question 13

Describe what happens in a condensation reaction

Answer 13

Two molecules are joined together and water is removed.

Question 14

What type of reaction breaks a glycosidic bond?

Answer 14

A hydrolysis reaction

Question 15

Describe what happens in a hydrolysis reaction

Answer 15

A molecule is broken apart using water.

Question 16

Describe the structure of glycogen

What molecules and what bonds?

Answer 16

Made up of many alpha glucose molecules joined by either alpha 1,4 or alpha 1,6 bonds. Highly branched and compact.

Question 17

Describe the structure of starch

What is it made of and what bonds?

Answer 17

Made of amylose (alpha 1,4 bonds) and amylopectin (alpha 1,6 bonds). Coiled and branched.

Question 18

Why is glycogen useful as a storage molecule in animals?

Answer 18

It’s highly compact.
Highly branched so it can be broken down by enzymes easily for respiration.
It’s insoluble.

Question 19

What 3 elements are triglycerides made up of?

Answer 19

Carbon, hydrogen and oxygen.

Question 20

Describe the structure of a triglyceride

Answer 20

One molecule of glycerol attached to 3 fatty acid chains by ester bonds. Fatty acid chains may or may not contain double bonds.

Question 21

What is an ester bond?

Answer 21

A type of covalent bond which is found in triglycerides and phospholipids. Ester bonds join the fatty acid tails to the glycerol molecule.

Question 22

What is the difference between saturated and unsaturated fatty acids?

Answer 22

Unsaturated acids contain C=C double bonds.
Saturated fatty acids contain C-C single bonds.