Molecules Of Life

Question 1

How many elements are there and which are required for living?

Answer 1

There are 92 elements that occur naturally of those 8 elements are required for life, they are: - hydrogen - nitrogen - oxygen - carbon - potassium - calcium - phosphorus - Sulfur

Question 2

What is a compound?

Answer 2

A substance consisting of two or more elements in a fixed ratio, it has characteristics different from those of their origin elements

Question 3

What are elements?

Answer 3

An element is a substance that cannot be broken down to other substances by chemical reactions

Question 4

water, what are its:

structure

polarity

hydrogen bonds

properties

Answer 4

• water is a polar molecule meaning the opposite ends have opposite charges
• the polarity of water allows it to form hydrogen bonds with other water molecules

properties of water:

• its cohesive
• its adhesive and bonds with all molecules in a plant
• can regulate temperature
• versatile solvant

Question 5

what are the four classes of molecules

Answer 5

• carbohydrates
• lipids
• protein
• nucleic acid

Question 6

monosaccharides:

structure

example

function

Answer 6

monosaccharides consist of only one sugar molecule

example: glucose (six carbon chain)

they are the building blocks of di and polysaccharides

glucose is the primary source of chemical energy for plants

Question 7

disaccharides:

structure

example

function

Answer 7

synthesised from two monsaccharide molecules

a water molecule is removed

example: sucrose
function: major transport sugar in plants

Question 8

polysaccharides for storage:

example

structure

Answer 8

amylose, which is branched molecule acts as a store for sugars

Question 9

polysaccharides for structure

example

structure

Answer 9

cellulose, composed of monomers of glucose

Question 10

lipids

function

structue

Answer 10

structure:

• made from 1 glycerol and 3 fatty acids
• known as triglycerides
• lipids are non polar(they are hydrophobic)

Question 11

difference between saturated and unsaturated fats

Answer 11

saturated:

• are densely packed
• firm at room temperature
• e.g animal fats

unsaturated:

• has bends in chains preventing close packing
• lower melting point, tend to be oily at room temp
  e. g canola, peanut oil

Question 12

phospholipids:

structure

location and function within cells

Answer 12

location: they are found in the walls of plant cells
function: they are used for structure as well as preventing water loss from plant surfaces