Biological Compounds Topic 1

Question 1

Name the 4 key inorganic ions for living organisms

Answer 1

Magnesium (Mg2+)
Iron (Fe2+)
Calcium (Ca2+)
Phosphate (PO4^3-)

Question 2

Role of Mg2+ in plants?

Answer 2

Producing chlorophyll

Question 3

Role of Fe2+ in animals

Answer 3

Used in haemoglobin, to transport oxygen

Question 4

Role of PO4³- in living organisms

Answer 4

To produce ADP and ATP

Question 5

Role of CA²+ in living organisms

Answer 5

Strengthen tissues eg bones and teeth in animals and cell walls in plants

Question 6

Why is water a polar molecule?

Answer 6

The oxygen is more electronegative than the hydrogen. So O attracts electron density in the covalent bond more forming a δ- in O and a δ+ in H

Question 7

Describe the hydrogen Bonding in water molecules

Answer 7

Weak Intermolecular forces of attraction form between a lone pair on the δ- O and a δ+ H on an adjacent molecule

Question 8

What is a metabolite?

Answer 8

A molecule formed or used in metabolic reactions

Question 9

Describe the role of water as a metabolite

Answer 9

Water is a reactant in photosynthesis and hydrolysis reactions. And is a product of aerobic respiration and condensation reactions

Question 10

Why is waters high specific heat capacity important for organisms

Answer 10

Acts as a temperature buffer, preventing large changes in core temperature and maintaining optimum enzyme activity

Question 11

Why is waters high latent heat of vaporisation important for organisms?

Answer 11

When water evaporates it has a cooling effect. Important for homeostasis, so organisms can lose heat by panting or sweating

Question 12

Why is water important as a solvent for organisms

Answer 12

It is a polar universal solvent. Enabling chemical reactions to take place within cells, the transport or materials in the plasma and removal of metabolic waste

Question 13

Why does water have a high surface tension/

Answer 13

Due to the ordered arrangement and cohesion of molecules at the surface or water

Question 14

Why is the high surface tension of water important for organisms?

Answer 14

Enables the transport of water and nutrients through plant stems and small blood vessels in the body, and allows small insects to walk on the surface of water

Question 15

What is a monosaccharide?

Answer 15

A simple sugar with the formula of Cn(H2O)n

Question 16

Give an example of some monosaccharides

Answer 16

Fructose, Ribose, Deoxyribose, alpha/beta glucose, galactose

Question 17

Draw alpha glucose

Answer 17

-OH on the far right is facing down

Question 18

Draw beta glucose

Answer 18

-OH on the far right is facing up

Question 19

What is the name of the bond formed when 2 monosaccharides react?

Answer 19

Glycosidic bond

Question 20

What is a disaccharide?

Answer 20

Molecule formed by the condensation of 2 monosaccharides, forming a glycosidic bond. Formula (C12H22O11)

Question 21

Give examples of disaccharides and how they’re formed

Answer 21

Sucrose - Glucose + Fructose
Maltose (2x alpha glucose)
Lactose - Glucose + Galactose

Question 22

What is a polysaccharide?

Answer 22

A polymer of monosaccharides, formed by many condensation reactions

Question 23

Give some examples of polysaccharides

Answer 23

Starch, Glycogen, Cellulose, Chitin

Question 24

What is the function of starch?

Answer 24

Energy storage in plants

Question 25

Describe the structure of starch

Answer 25

Polymer of alpha glucose monomers 2 forms - amylose and amylopectin Amylose - 1-4 glycosidic bonds and unbranched Amylopectin - 1-4/1-6 glycosidic bonds and branched

Question 26

What is the function of glycogen?

Answer 26

Energy storage in animals

Question 27

How does the structure of glycogen relate to its function?

Answer 27

It is highly branched, so it rapidly hydrolyses into glucose

Question 28

Describe the structure and function of cellulose

Answer 28

Linear polysaccharide that is the main component of the cell wall in plants Consists of many beta glucose molecules joined by beta 1-4 glycosidic bonds Alternate glucose molecules rotated 180 degrees allowing hydrogen bonds between parallel chains forming myofibirils

Question 29

Describe the structure and function of chitin

Answer 29

Linear polysaccharide found in the exoskeleton of insects and crustaceans as well as fungal cell walls Consists of many beta glucose molecules with amino acid side chains joined by beta 1-4 glycosidic bonds Alternate glucose molecules rotated 180 degrees allowing hydrogen bonds between parallel chains forming myofibirils

Question 30

Explain how a triglyceride is formed

Answer 30

One molecule of glycerol forms ester bonds with 3 fatty acids via condensation reactions

Question 31

Explain the importance of the structure of triglycerides to their function

Answer 31

- High energy to mass ration, high calorific value from oxidation, so useful energy store - Insoluble, so it doesnt effect the water potential of cells and waterproofs them - Thermal insulation, as they are a slow conductor of heat - Buoyancy, from a lower density than water

Question 32

What is a phospholipid?

Answer 32

Formed by the condensation of one molecule of glycerol, 2 of fatty acid and a phosphate group

Question 33

Relate the structure of phospholipids to their function

Answer 33

Glycerol backbone attached to to hydrophobic fatty acid tails and one hydrophilic polar phosphate head: - Forms phospholipid bilayer in water (component of cell membrane) - Tails splay outwards - allowing for waterproofing, eg skin

Question 34

Difference between saturated and unsaturated fats

Answer 34

Saturated - have no C=C bonds and are solid at room temp because they have strong intermolecular forces Unsaturated - have one or more C=C bonds, and are liquid at room temp due to week intermolecular forces.

Question 35

What is meant by low density lipoprotein (LDL)?

Answer 35

Combination of triglycerides from unsaturated fats and protein Blocks receptor sites, reducing cholesterol absorption Known as 'bad' lipoproteins

Question 36

How do LDLs contribute to the risk of cardiovascular?

Answer 36

The high blood cholesterol level caused by LDLs leads to formation of athersclerosis plaques

Question 37

Describe the general structure of an amino acid

Answer 37

Amine Group (-NH2) Variable side chain (R) Carboxyl group (-COOH) H atom

Question 38

How are polypeptides formed?

Answer 38

Many amino acid monomers join together in condensation reactions, forming peptide bonds (-CONH-)