Molecules to Metabolism

Question 1

What is the difference between atom, molecule, and compound?

Answer 1

1. Atom is a single particle of an element, consisting of a positively charged nucleus surrounded by negatively charged electrons
2. A molecule is a group of two or more atoms held together
3. A compound is a molecule consisting of different elements

Question 2

What are the 4 features of carbon that makes it the basis of organic life?

Answer 2

1. Carbon has the ability to form 4 covalent bonds
2. Carbon has the ability to form chains
3. Carbon has the ability to form bonds with carbon, hydrogen, oxygen, nitrogen, and phosphorous
4. Carbon-Carbon bonds are very strong and stable

Question 3

What is an organic compound?

Answer 3

An organic compound is a compound that contains carbon and is found in living things

Question 4

What are carbohydrates?

Answer 4

Polar, hydrophilic macro-molecules consisting of carbon, oxygen, and hydrogen (the latter forming a 1:2 ratio usually).

Question 5

What are the 3 main functions of carbohydrates?

Answer 5

1. Source of energy
2. Important as recognition molecule
3. Important as a structural component

Question 6

What are lipids?

Answer 6

Non-polar, hydrophobic macro-molecules, including steroids, waxes, fatty acids, and triglycerides.

Question 7

What are the 3 main functions of lipids?

Answer 7

1. Phospholipids and cholesterol serve as a major component of cell membranes
2. Fats and oils are utilized as a long-term energy storage molecule
3. Steroids act as signalling molecules

Question 8

What are proteins?

Answer 8

Macro-molecules consisting of one or more chains of amino acids. Amino acids contain carbon, hydrogen, oxygen, and nitrogen.

Question 9

What are the 3 main functions of proteins?

Answer 9

1. Enzymes are involved in catalysis
2. Function as structural molecules
3. Play a role in cellular signalling

Question 10

What are nucleic acids?

Answer 10

Macro-molecules consisting of many nucleotides linked in a chain. Each nucleotide contains a nitrogenous base, a pentose sugar, and a phosphate group.

Question 11

What are the 3 main functions of nucleic acids?

Answer 11

1. Stores the genetic material of all cells and determines the inherited features of an organism
2. DNA functions as a code for protein assembly
3. RNA plays an active role in the manufacturing of proteins

Question 12

How to identify and differentiate between the 3 main macro-molecules?

Answer 12

1. Carbohydrates have oxygen and hydrogen in a ratio of 1:2
2. Lipids contain relatively less oxygen than carbohydrates
3. Proteins contain C, H, O, and N - N being the defining character; some proteins also contain S

Question 13

What is metabolism?

Answer 13

Metabolism is the totality of chemical processes that occur within an organism in order to maintain life. It consists of pathways by which one type of molecule is transferred into another, in a series of steps.

Question 14

What are the two functions of metabolism?

Answer 14

1. Enables the synthesis of new materials (anabolism)

2. Provides source of energy, i.e. ATP, for cellular processes (catabolism)

Question 15

What is anabolism? [3 points]

Answer 15

• Anabolism is the synthesis of complex molecules from simpler molecules
• Example: macro-molecules are formed from monomers
• Anabolic reactions require energy (ATP)

Question 16

What are 4 examples of anabolism?

Answer 16

1. Protein synthesis
2. DNA synthesis
3. Photosynthesis
4. Synthesis of polysaccharides (like starch and glycogen)

Question 17

What is catabolism?

Answer 17

• Catabolism is the breakdown of complex molecules into simpler molecules
• Example: monomers are formed from macro-molecules
• Catabolic reactions release energy (ATP)

Question 18

What are 3 examples of catabolism?

Answer 18

1. Digestion of food in the mouth, stomach, and small intestine
2. Cell respiration
3. Digestion of complex carbon compounds by decomposers

Question 19

What is urea?

Answer 19

• Urea is a component of urine and is produced as a means of excreting nitrogen (i.e. excess amino acids)
• Urea is mainly used as a nitrogen source in fertilizer

Question 20

What is vitalism?

Answer 20

Earlier, it was thought that living organisms were composed of organic compounds that could only be produced in living organisms because a “vital force” was needed.

Question 21

How was vitalism disproved?

Answer 21

In 1828, Friedrich Wohler synthesized urea artificially using silver isocyanate and ammonium chloride, demonstrating that an organic compound can be artificially synthesized.