Biomolecules

Question 1

Describe the structure of a water molecule

Answer 1

-One oxygen atom covalently bonded to 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 six 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

Cohesion is 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 against the pull of gravity up the xylem.

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 which joins a monosaccharide to another molecule (usually another monosaccharide to form a disaccharide) It has the following structure

C C
\ /
O

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

Answer 16

-Made up of many alpha glucose molecules joined by either alpha 1-4 or alpha 1-6 bonds
-Highly branched
-Compact

Question 17

Describe the structure of starch

Answer 17

-Made of amylose (joined by alpha 1,4 bonds) and amylopectin (joined by alpha 1,4 and alpha 1-6 bonds)
-Coiled are branched

Question 18

Why is glycogen useful as a storage molecule in animals?

Answer 18

-It is highly compact
-It is highly branched so it can be broken down by enzymes easily for respiration
-It insoluble

Question 19

What three elements are triglycerides made up of?

Answer 19

Carbon, hydrogen, and oxygen

Question 20

Draw the structure of glycerol

Answer 20

H H H
| | |
H-C-C-C-H
| | |
OHOHOH

Question 21

Describe the structure of a triglyceride

Answer 21

-One molecule of glycerol
-Attached to three fatty acid chains by ester bonds
-Fatty acid chains may or may not contain double bonds

Question 22

Describe the structure of a triglyceride

Answer 22

-One molecule of glycerol
-Attached to three fatty acid chains by ester bonds
-Fatty acid chains may or may not contain double bonds

Question 23

What is an ester bond?

Answer 23

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