2.1 & 2.3 (Topic 2)

Question 1

Define “molecular biology.”

Answer 1

explaining of biological processes from the structures of the molecules and how they interact with each other (water, carbohydrates, lipids, proteins, nucleic acids)

Question 2

Compare the benefits of a reductionist vs. systems approach to studying biology.

Answer 2

Reductionism breaks down biochemical processes into their component parts
- all these reactions together help study the emergent properties of that system
Systems biology focuses on complex interactions within biological systems
- shows how these interactions give rise to the functions and behaviors of that system

Question 3

Outline the number and type of bond carbon can form with other atoms.

Answer 3

Carbon can form four stable covalent bonds

Question 4

List the four major classes of carbon compounds used by living organisms.

Answer 4

Carbohydrates, lipids, proteins, and nucleic acids

Question 5

Define metabolism.

Answer 5

the totality of chemical processes that occur within a living organism in order to maintain life. It is the web of all enzyme-catalysed reactions that occur within a cell or organism

Question 6

State the role of enzymes in metabolism.

Answer 6

Enzymes build up or break down all the molecules involved in maintaining life.

Question 7

Define anabolism, monomer and polymer.

Answer 7

anabolism: synthesis of complex molecules in living organisms from simpler ones together with the storage of energy; constructive metabolism
monomer: small molecules, mostly organic, that can join with other similar molecules to form very large molecules
polymer: class of synthetic substances composed of multiples of simpler units called monomers

Question 8

Describe condensation (dehydration synthesis) reactions.

Answer 8

This is when two hydroxyl groups (or carboxyl, or etc) meet to form a different molecule connected by oxygen, as well as one water molecule, hence the name, “condensation reaction.”

Question 9

Define catabolism.

Answer 9

breakdown of complex molecules in living organisms to form simpler ones, together with the release of energy; destructive metabolism

Question 10

Contrast anabolism and catabolism.

Answer 10

anabolism requires energy to grow and build

catabolism uses energy to break down

Question 11

Describe hydrolysis reactions.

Answer 11

• use water to breakdown polymers into monomers and is the opposite of dehydration synthesis, which forms water when synthesizing a polymer from monomers
• break bonds and release energy

Question 12

Describe how vitalism was disproved using the synthesis and urea and name the scientist behind it

Answer 12

• Vitalism as a theory has since been disproven with the discovery that organic molecules can be artificially synthesised
• Frederick Woehler

Question 13

Define monosaccharide, disaccharide and polysaccharide.

Answer 13

monosaccharide: simplest carbohydrates, the building block molecules, and contain single sugar units
disaccharide: made of two sugar units (monosaccharides)
polysaccharides: contain several sugar units (monosaccharides)

Question 14

List three examples of monosaccharides.

Answer 14

glucose, galactose, fructose

Question 15

List three examples of disaccharides.

Answer 15

lactose, sucrose, maltose

Question 16

List three examples of polysaccharides.

Answer 16

cellulose, starch, glycogen

Question 17

Explain a condensation reaction connecting two monosaccharides in the formation of a disaccharide.

Answer 17

An -H from the hydroxyl on carbon #1 of one monosaccharide combines with an -OH from the hydroxyl on carbon #4 of the other monosaccharide. The -H and -OH combine to form water. A bond is formed with a C-O-C bridge between the two monosaccharides

Question 18

Describe the differences between saturated and unsaturated (mono- or poly-) fatty acids.

Answer 18

Saturated fats have no double bonds, while monounsaturated fatty acids have one double bond and polyunsaturated fatty acids have multiple double bonds within the molecule.

Question 19

Describe the differences between cis- and trans- fatty acids.

Answer 19

Cis fatty acids have the hydrogens attached to the double bonded carbons on the same side, while trans fatty acids have them on the opposite sides.

Question 20

Outline the difference between fats and oils.

Answer 20

• fats are composed of high amounts of saturated fatty acids which will take a solid form at room temperature
• oils are composed of mainly unsaturated fatty acids which will take a liquid form at room temperature

Question 21

Explain a condensation reaction connecting fatty acids and glycerol to form a triglyceride

Answer 21

• The hydroxyl groups of glycerol combine with the carboxyl groups of the fatty acids to form an ester linkage
• This condensation reaction results in the formation of three molecules of water

Question 22

State two functions of triglycerides.

Answer 22

• store unused energy

- provide the body with energy

Question 23

Contrast the structure and functions of cellulose

Answer 23

cellulose: linear; forms plant cell walls - gives rigidity and support

Question 24

Contrast the structure and functions of amylose

Answer 24

amylose: helical; storage unit in plants

Question 25

Contrast the structure and functions of amylopectin

Answer 25

amylopectin: linear, branched; storage unit in plants

Question 26

Contrast the structure and functions of glycogen

Answer 26

glycogen: linear, very branched; energy storage in animals

Question 27

Discuss the relationship between saturated fatty acid and trans-unsaturated fat intake and rates of coronary heart disease.

Answer 27

• Saturated fats and trans-unsaturated fats raise blood cholesterol levels
• Raise LDL in blood - carries cholesterol from the liver to the body cells
• Saturated fats raise LDL
• Trans fats raise LDL and lower HDL
• High LDL levels = particles form deposits in arteries and accumulation with developing plaques
  
  • Restricts blood flow
  • Results in heart disease

Question 28

Explain the energy storage of lipids compared to that of carbohydrates.

Answer 28

Lipids
- Long-term energy storage
- Triglycerides
- Fat stored in adipose tissue
- Amount of energy released in cell respiration per gram of liquid is 2x that of 
  carbs and protein

Carbohydrates

• Short-term energy storage
• Glycogen is easily/rapidly broken down into glucose

Question 29

Calculate BMI using the formula.

Answer 29

(imperial)

lbs/in^2*703= bmi