B1.1 Carbohydrates and Lipids

Question 1

Chemical properties of Carbon

Answer 1

Carbon atoms can form four covalent bonds allowing a variety of stable compounds to exist. Covalent bonds are very strong so gives stability.

Question 2

Information on Carbon to Carbon bonds

Answer 2

Specifically very strong and stable, long-chain carbon compounds provide framework for many molecules: longer the chain, the more stable it is.

Question 3

Condensation reaction

Answer 3

Reaction in which two molecules are combined together, forming a larger, more complex polymer and a molecule of water.
Monomer + Monomer –> Water + Dimer.

Question 4

Hydrolysis reaction

Answer 4

Reaction in which a polymer breaks down into 2 smaller, less complex molecules using the OH and H from a split water molecule.

Question 5

Biomolecules

Answer 5

Molecules found in living organisms which are essential to living processes. All biomolecules contain the element carbon.

Question 6

Basic sub-unit of a carbohydrate

Answer 6

Monosaccharide which are simple sugars. They are either made up of 4 carbons (pentose) or 6 carbons (hexose). A monosaccharide can be in straight-chain/linear form or ring form. check notes.

Question 7

Important properties of monosaccharides: glucose

Answer 7

Relatively small and soluble in water so can easily be transported in living tissue (living tissue based around water).
Oxidation of glucose provides large amounts of energy.
Glucose and many carbohydrates are stable due to covalent bonds; great for energy storage.

Question 8

4 types of polysaccharides

Answer 8

Glycogen
Amylose
Amylopectin
Cellulose

Question 9

Structure and function of Amylose

Answer 9

Only contains alpha glucose, contains 1-4 glycosidic bonds to connect each glucose monosaccharide. Unbranched so has helical shape and is linear chained. check notes diagram. Comprises 20-30% of starch.

Question 10

Structure and function of Amylopectin

Answer 10

Only contains alpha glucose, contains both 1-4 and 1-6 glycosidic bonds. Branched structure. check notes diagram. Comprises 70-80% of starch.

Question 11

Structure and function of Glycogen

Answer 11

Same structure as amylopectin but tends to branch more (highly branched, more 1-6 glycosidic bonds) and is created inside body of an animal. Stored as an energy reserve in animals within the liver and muscles.

Question 12

Structure and function of Cellulose

Answer 12

Only contains beta glucose, alternating orientation, making it able to form microfibrils that have extremely strong tensile strength: these are the basis of plant cell walls and give plants their firm sturdy, structure to stand upright and help resist turgor pressure. Insoluble.

Question 13

Property of starch and glycogen that make them good for storage

Answer 13

Large molecules so are less soluble, but when required, hydrolysis can break the chains. They branch so become compact.

Question 14

Biomolecules that exist in combinations with others

Answer 14

Glycoprotein (carbohydrate + protein)
Glycolipid (carbohydrate + lipid)
Lipoprotein (lipid + protein)

Question 15

Glycoproteins

Answer 15

Carbohydrate chain bound to a protein found on cell membranes. Contain a short chain of monosaccharides called Oligosaccharides. Cells can read these chains on other cells in the process of cell recognition: important to identify body tissue from foreign cells or pathogens.

Question 16

Glycolipid

Answer 16

Carbohydrate chain bound to a phospholipid located on the surface of cell membranes involved in cell recognition and membrane stability.

Question 17

Lipoprotein

Answer 17

Shell-like structure made of phospholipids and proteins whose function is to transport lipids around the body via the blood.

Question 18

4 main types of blood, classified by the antigens on their surface

Answer 18

A
AB
B
O
These blood type combinations are made by different oligosaccharide chains, called A, B and O. Purpose of these glycoproteins is to signify if foreign blood entered body. Rejects blood and clots if wrong type is injected.

Question 19

Lipids

Answer 19

Broad type of biomolecule which are hydrophobic so is easily dissolved in non-polar solutions but cannot easily dissolve in polar solutions.

Question 20

Common types of lipids

Answer 20

Fats, Oils, Waxes, and Steroids.

Question 21

Fatty acids

Answer 21

Largely composes lipids, determines certain physical properties. Starts with carboxyl group.

Question 22

Two lipid structures created by with fatty acid chains

Answer 22

Triglycerides and Phospholipids.

Question 23

Triglyceride structure

Answer 23

3 separate fatty acid chains undergo condensation reactions with the open hydroxyl groups on the glycerol to create a triglyceride structure. check notes.

Question 24

Phospholipid structure

Answer 24

2 separate fatty acid chains undergo condensation reactions with the open hydroxyl groups on the glycerol. Instead of a third fatty acid, it is replaced by a phosphate group. check notes.

Question 25

Triglyceride properties and function

Answer 25

Used as long-term storage and insulation, stored in mammals in adipocytes, forming adipose tissue mainly stored under the skin. Stable, hydrophobic, stores more energy per gram, helps retain body heat, shock absorbent.

Question 26

Phospholipid properties and function

Answer 26

They are amphipathic meaning they have both hydrophilic and hydrophobic regions. Phosphate head is polar and hydrophilic whilst hydrocarbon tail is non-polar and hydrophobic. Due to this, the hydrophobic tails will be next to each other because they are away from water, hydrophilic heads come in contact with water. This double membrane creates a structure called a phospholipid bilayer.

Question 27

Types of fatty acid

Answer 27

Saturated fatty acid: single bond between each carbon atom.
Unsaturated cis-fatty acid: double bond between carbon atom, hydrogens on the same side so creates a bend in the chain.
Unsaturated trans-fatty acid: hydrogens on opposite sides so does not bend the chain.

Question 28

Steroid structure and properties

Answer 28

Non-polar. Consists of 4 hydrocarbon rings: 3 cyclohexane rings and one cyclopentane ring. Contain 17 total carbons within the rings. Mainly hydrophobic so is able to pass through the phospholipid bilayer