chemistry of life part 1 {module 1}

Question 1

() are formed when a group of atoms (the same atoms or two or more different atoms) bond together covalently

Answer 1

Molecules

Question 2

A () is a substance that is composed of two or more atoms of different elements that bond in fixed proportions

Answer 2

compound

Question 3

Organic compounds always contain (), but not all compounds containing are organic compounds.

Answer 3

carbon

Question 4

For a carbon-containing compound to be considered organic, one of the carbons needs to be () This is generally hydrogen, but can also be oxygen or nitrogen.

Answer 4

covalently bonded

Question 5

All living things are made up of ()

Answer 5

organic compounds

Question 6

The human body consists of about () water

Answer 6

65%

Question 7

Water is important for (name 7)

Answer 7

temperature regulation, form, and support, transport, lubrication, acts as a solvent, functions as a medium for chemical reactions, and finally, water can be a reactant itself.

Question 8

elaborate temperature regulation

Answer 8

Temperature regulation:

Humans have sweat glands, which produce sweat when the body gets hot. Sweat cools the body as it evaporates. This process is called perspiration. In plants, it is called transpiration, but more about that later in this course.

Question 9

elaborate form and support

Answer 9

Form and support:

Water plays a vital role in plants and animals when it comes to providing form and support. In animals such as jellyfish and worms, water fills special chambers to give their bodies support. This process by which animals use water for form and to help with movement is called hydrostatic skeleton. Similarly, plants use water to help them grow upright and keep their shape. The water pressure used to achieve this is called turgor pressure inside the cells.

Question 10

elaborate transport

Answer 10

Transport:

Water transports substances around the body. Water is the main constituent of blood, which transports blood cells, hormones, dissolved gasses, nutrients, and electrolytes around the body.

Question 11

elaborate lubrication

Answer 11

Water is the main constituent of saliva and tears, both serving the function of lubrication. Saliva aids in the swallowing of food and helps it to pass through the alimentary canal. Tears keep your eyes moist and lubricated.

Question 12

elaborate solvent

Answer 12

Solvent:

Substances that dissolve in liquid are called soluble. The liquid that substances dissolve in is called the solvent. Water is a universal solvent as many substances dissolve in water (more than any other liquid). We call these substances water-soluble.

Question 13

elaborate why water is a medium for chemical reactions

Answer 13

All chemical reactions in living organisms occur in water

Question 14

minerals can be divided into two groups: ()

Answer 14

Macro and Micro-nutrients

Question 15

elaborate why water can be a reactant

Answer 15

Water can be used for chemical reactions e.g during hydrolysing reactions, water is added to break down large molecules into smaller ones

Question 16

Dietary minerals are elements that living organisms need to live and maintain their health. Some of the essential minerals needed by humans include ()

Answer 16

calcium, potassium, sulphur, nitrogen, and magnesium

Question 17

Fertilisers are a mix (natural or non-natural) of chemical substances that put the depleted nutrients back into the soil. This improves the soil nutrient content to make sure that the next round of crops can grow well. () are added to the soil in the form of inorganic fertilisers.

Answer 17

Nitrates and phosphates

Question 18

Using too much fertiliser, or in large amounts is harmful to the environment. When it rains, or when the soil is irrigated, the fertilisers wash off into rivers, where they poison plants and animals. As the fertilisers build up and accumulate in rivers, it leads to a process known as ()

Answer 18

eutrophication

Question 19

elaborate on eutrophication

Answer 19

Eutrophication is the process when:

Excessive nutrients enter waterways

Nutrients help the aquatic plants to grow faster, especially that of algae (this depletes the water of its oxygen content)

Algae bloom occurs (preventing other aquatic organisms from photosynthesizing - also reducing oxygen content)

Algae dies and is decomposed by bacteria

The decomposition of algae increases oxygen demand

Oxygen levels further decrease

Fish and other aquatic organisms die

Question 20

Plants require large quantities of oxygen and sunlight for ()

Answer 20

photosynthesis.