Chapter 2.A - Molecular Biology

Question 1

Carbs contain?

Answer 1

CHO

→ H:0 2:1 ratio

Question 2

Proteins contain?

Answer 2

CHONS

Question 3

Nucleic acids contain?

Answer 3

CHONP

Question 4

Metabolism

Answer 4

Web of enzyme catalysed reactions in a cell or oraganism.

Question 5

Anabolism

Answer 5

Synthesis of complex molecules from simpler molecules = formation of macro-molecules from monomers by CONDENSATION reactions.

Question 6

Catabolism

Answer 6

The break down of complex molecules into simpler molecules = HYDROLYSIS of macro-molecules into monomers.

Question 7

Cohesive properties of water.

Answer 7

Binding together of water molecules to other water molecules

= useful for water transport in plants = sucked up through xylem tube!

Question 8

Adhesive properties of water.

Answer 8

H. bonds from between water and other polar molecules = causing water to stick to them!
+ causes water to be drawn out of the nearest xylem vessel = keeps walls moist so CO2 can be absorbed for photosynthesis.

Question 9

Thermal properties of water.

Answer 9

High specific heat capacity.
+ H. bonds restrict the motion of water molecules
+ increase in temp of water require H. bond to be broken. = needs energy = LARGE.

Question 10

Why is water a thermally stable habitat for aquatic organisms?

Answer 10

Water’s temp remains relatively stable in comparison to air or land.

Question 11

High Latent Heat of Vapourisation

Answer 11

When a molecule evaporates = separates from other mol. in a liquid = becomes vapour molecule = heat needed.

Question 12

Why is water a good evaporative coolant?

Answer 12

Evaporation has cooling approach

+ It takes a considerable amount of heat = needed to evap. water = cuz the H.bond hv. to be broken

Question 13

High boiling point of water

Answer 13

Boiling pt. is high
+ therefore water = liquid in a broad range of temperatures
+ 0 - 100 degrees celcius

Question 14

How does water prevent charged or polar molecules from clumping together and keeping them in solution?

Answer 14

The polar nature of water molecules means they can form shells around the charged and polar molecules.

Question 15

Hydrophobic interactions

Answer 15

Forces that cause non-polar molecules to join together.

Question 16

If non-polar molecules = surrounded by water molecules what happens.

Answer 16

H. bonds form between the water molecules

+ NOT between the non-polar molecules and the water molecules

Question 17

Monosaccharides

Answer 17

+ Glucose
+ Ribose
+ Fructose
+ Galactose

Question 18

Dissacharides and what they’re made of

Answer 18

+ Maltose (Glucose + Glucose)
+ Sucrose (Glucose + Fructose)
+ Lactose (Glucose + Galactose)

Question 19

Polyssaccharides and what they’re made of

Answer 19

+ Cellulose (beta glucose)
+ Starch (alpha glucose)
+ Glycogen (alpha glucose)

Question 20

What type of bond is formed in condensation reaction between the 2 sugars?

Answer 20

Glycosidic bond (–O–)

Question 21

What does C1 and C4 lose when 2 sugars bond?

Answer 21

C1 = loses OH
C4 = loses H bonded to the O

Question 22

The 2 types of polysaccharides in startch and their properties

Answer 22

+ Amylose = Chain of alpha-glucose
-Unbranched
-Forms and helix (As the Hydrogen’s repel each other to it coils up)
+ Amylopectin = Chain of alpha-glucose
-Branched
-Globular
Makes the energy more accessible = makes each glucose molecule more accessible and breaks down easier.

Question 23

Cellulose properties and functions

Answer 23

+ Can form bundles w/ H.bond linking the cellulose molecules
+ Cellulose microfibrils = parallel to e.o
+ used to increase tensile strength → prevents cells from bursting
+ Basis of plant cell wall
→ important dietary fibre for humans when ingested (can’t digest)

Question 24

Is amylopectin hydrophobic or hydrophilic?

Answer 24

Hydrophilic BUT is too large to be soluble in water so it can be used for storage

Question 25

Properties of Glycogen and it’s function

Answer 25

+ Similar to starch BUT has more branchings
→ more compact
+ easy to add extra glucose molecule or remove a glucose molecule = done one both ends of unbranched molecule or any of the branched ones
+ Made by animals and some fungi
= stored in the liver and some muscles of humans = store of energy as glucose is soluble (SHORT TERM storage)

Question 26

Fats physical state(s)

Answer 26

+ Liquid at body temp (37°C) → Adipose tissue

+ Solid at room temp (20°C)

Question 27

Oils physical state

Answer 27

+ Liquid at BOTH room and body temp

Question 28

Triglycerides are composed of?

Answer 28

3 fatty acids and 1 glycerol

→ by condensation reaction

Question 29

What is lost from the fatty acid and what is lost from the glycerol when a ESTER bond is formed?

Answer 29

+ Glycerol loses H

+ Fatty acid loses hydroxyl group (-OH)

Question 30

Why are LIPIDS preferred over CARBS for LT energy storage?

Answer 30

+ The amt of energy released in cell respiration is 2x that of carbs!
+ Mass advantage: Fats form pure droplets BUT 1g of glycogen has abt 2g og water
+ Lipids is 6x more efficient in the amt of energy stored/g of body mass

Question 31

What are other uses of fats in the body?

Answer 31

+ Lipids are poor conductor of heat = good insulators
+ FATS = liquid at room temp → act as shock absorber
(adipose tissue around organs)