Chapter 1- Biological Molecules

Question 1

What is covalent bonding?

Answer 1

Atoms share a pair of electrons in outer shell

Outer shell of both atoms are filled and more stable

Question 2

What is ionic bonding?

Answer 2

Ions with opposite charges attract one another
Electrostatic is known as ionic bond
Weaker than covalent bond.

Question 3

What is hydrogen bonding?

Answer 3

Electrons within a molecule are not evenly distributed but spend more time at one position . This region is more negatively charged than the rest. Molecule with uneven distribution of charge is a polar molecule. Negative region attracts positive region. A weak electrostatic bond is formed . Individually weak but collectively form important forces that alter physical experience.

Question 4

What is a condensation reaction?

Answer 4

Each time a new sub unit it attached to the polymers a molecule of water is formed.

Question 5

What is hydrolysis?

Answer 5

Through addition of water, the bonds linking sub units break, thereby splitting molecule into its constituent parts

Question 6

What is metabolism?

Answer 6

All chemical processes that take place in living organisms

Question 7

What are most polymers made of?

Answer 7

Carbon
Hydrogen
Oxygen
Nitrogen

Question 8

What is the basic monomer of carbohydrates?

Answer 8

Sugar known as a saccharide

Question 9

What is a monosaccharide, and what is it’s general formula?

Examples of monosaccharides?

Answer 9

Sweet tasting soluble substances
(CH2O)n
N =3-7
Glucose galactose fructose

Question 10

What is glucose?
What is its formula?
How many isomers does glucose have?

Answer 10

Hexose sugar
C6H12O6
Alpha glucose
Beta glucose

Question 11

What is the difference between alpha glucose and beta glucose?

Answer 11

Alpha - H at top

Beta -OH at top

Question 12

Glucose joined to glucose forms?
Glucose joined to fructose forms?
Glucose joined to galactose forms?

Answer 12

Maltose
Sucrose
Lactose

Question 13

What bond is formed when a condensation reaction occurs?

What breaks the glycosidic bond?

Answer 13

Glycosidic bond

Hydrolysis

Question 14

Why are polysaccharides suitable for storage?

What happens when polysaccharides are hydrolysised ?

Answer 14

Large molecules, that are insoluble

Break down into disaccharides or monosaccharides

Question 15

Where is starch found in?

Why is it important?

Answer 15

Plants in the form of small grains found in storage organs

Forms major component of food/major energy source

Question 16

Formation of starch chains?

Answer 16

Made from alpha glucose

Can be branched or unbranched
The unbranched chain is wound into a tight coil and makes a molecule very compact

Question 17

Why is starch’s structure suited for its function? Give five examples?

Answer 17

• Insoluble doesn’t affect water potential so water is not drawn into the cells by osmosis
• Large insoluble doesn’t diffuse out of cells
• Compact, a lot can be stored in small spaces
• When hydrolysed forms alpha glucose which can easily be transported and used in respiration
• Branch form has many ends can be acted by enzyme simultaneously glucose monomers are released rapidly

Question 18

Where is starch never found in?

What Is found in the cells instead?

Answer 18

Animal cells

Similar polysaccharide glycogen

Question 19

Where is glycogen found?
What is the structure of glycogen?
What does it do for animals?
Where is it mainly stored?

Answer 19

Animal bacteria cells
Shorter chains more highly branches
Major carbohydrate storage product

Question 20

Why is the mass of carbohydrate stored relatively small?

Answer 20

Fat is the main storage molecule in animals

Question 21

Why does glycogen structure suit its storage?

Give 4 examples?

Answer 21

Insoluble doesn’t draw water in by osmosis
Insoluble doesn’t diffuse out of cells
Compact
More highly branched more ends can be acted on by enzymes releasing of glucose molecules used in respiration

Question 22

What happens in glycogen when enzymes act on the branches?

Answer 22

Rapidly broken down to form glucose monomers used in respiration. Important to animals which have a higher metabolic rate and respiratory rate than plants

Question 23

Why is cellulose different to starch and glycogen?

Answer 23

Made of monomers of beta glucose which produces fundamental differences in structure and function,

Question 24

What is the formation of cellulose?

When cellulose is grouped what does it form?

Answer 24

Straight unbranched that run parallel to one another allowing hydrogen bonds to form cross linkages between adjacent chain.
Overall number of hydrogen bonds strengthens cellulose
Microfibrils arranged in parallel groups called fibres

Question 25

Why is cellulose a major component of a plant cell? | How the cellulose wall prevent bursting?

Answer 25

Provides rigidity to plant cell, prevents cell from bursting when water enters it by osmosis. Exerting inward pressure that stops any further influx of water= living plant cells are strong important in maintaining leaves and stems to provide maximum surface area for photosynthesis

Question 26

How does cellulose suites to its structure?

Answer 26

Beta glucose form long straight unbranched chains Chains run parallel to each other and are crossed linked by hydrogen. Bonds adds to strength collectively Grouped to form microfibrils in turn form fibres provides more strength

Question 27

What do all lipids have ?

Answer 27

-Contain Carbon, hydrogen and water

Question 28

What is the role of lipids? | What are the two main groups of lipids?

Answer 28

In the cell membrane | Triglycerides and phospholipids

Question 29

What does phospholipids contribute to the membrane?

Answer 29

They contribute flexibility of membranes and transfer of the lipid-soluble substances across them

Question 30

Name four roles of lipids?

Answer 30

Source of energy Waterproofing Insulation Protection

Question 31

How does lipids play a role in energy?

Answer 31

When oxidised lipids provide more than twice the energy as the same mass of carbohydrates and release valuable water

Question 32

How do you lipids waterproof plants?

Answer 32

Insoluble in water so with plants and insects have waxy lipid cuticles that conserve water

Question 33

How do you lipids insulate?

Answer 33

Fat are slow conductors of heat and when stored beneath the body surface help to retain body heat And example is they also act as electrical insulator in the name myelin sheath around nerve cells

Question 34

What are triglycerides and what is the formation?

Answer 34

They have three fatty acid’s combined with a glycerol. Each fatty acid forms an ester bond with glycerol in a condensation reaction

Question 35

What is the difference in all triglycerides? | What do you all fatty acids contain?

Answer 35

``` All glycerol molecules are the same but there is a variation in the fatty acids Carbonyl group (— COOH) with hydrocarbon chain attached ```

Question 36

When is the fatty acid described as saturated? | What is it meant by mono-unsaturated?

Answer 36

If the chain has no carbon-carbon double bonds because all the carbon atoms are linked to the maximum number of hydrogen atoms , saturated with hydrogen When there is a single double bond

Question 37

Why is triglyceride a good source of energy ?

Answer 37

High ratio of energy storing carbon-hydrogen bonds to carbon atoms

Question 38

Why are triglycerides good storage molecules?

Answer 38

Low mass to energy ratio, much energy can be stores in a small volume Beneficial to animals as it reduces the mass they have to carry

Question 39

Why are triglycerides insoluble?

Answer 39

Large non polar molecules | Storage doesnt affect omosis in cels or water potential of them

Question 40

What is the difference between phospholipids and triglycerides?

Answer 40

One fatty acid molecule is replaced by a phosphate molecule

Question 41

Difference between phosphate molecule and a fatty acid?

Answer 41

Fatty acids repel water | Phosphate molecules attract water

Question 42

What is the scientific name for attracted to water and repels from water?

Answer 42

Hydrophilic head | Hydrophobic tail

Question 43

Molecules with two ends are called? | When phospholipids are placed in water what happens?

Answer 43

Polar Are placed in water they position themselves so that hydrophilic heads are closer to the water as possible and hydrophobic tails are far away

Question 44

What do phospholipids form in an aqueous solution?

Answer 44

A bilayer within cell surface membrane | A hydrophobic barrier is formed between the inside and outside of a cell

Question 45

What part of the phospholipids help hold the surface of the cell membrane?

Answer 45

The hydrophilic head

Question 46

How are glycolipids formed by phospholipids?

Answer 46

Phospholipids structure forms glycolipids by combining carbohydrates within the cell surface membrane