The molecular composition of organisms

Question 1

what are organic compounds?

Answer 1

Organisms produce characteristic complex compounds that contain carbon and hydrogen
These are called organic compounds because they were first found produced by animals or found in them

Question 2

where are inorganic-compounds found? what are some?

Answer 2

All other compounds whether in living or non-living things are called inorganic compounds
Inorganic compounds that are important for living things include water, oxygen, carbon dioxide, nitrogen and minerals

Question 3

what are the properties of the inorganic compound, water? why is water needed in cells?

Answer 3

Water molecules are cohesive: they tend to stick together. This allows thin columns of water to be pulled up tree trunks without breaking. Bonds between surface molecules causes surface tension
Water has high heat capacity: it can absorb a lot of heat with little temperature increase. Important in temperature regulation. The chemical reactions in cells produces heat but much of this is absorbed in water in the body without the cells heating too much
Water has a high heat of vaporisation which means that the evaporation of even small amounts cools the surface affectively.
Chemical reactions that occur in cells occur in a watery medium

Question 4

what is the inorganic molecule of oxygen needed for?

Answer 4

In most cells oxygen is needed to release energy from food molecules in processes called cellular respiration
Oxygen is needed to maintain activity of the cells

Question 5

Where is the inorganic molecule of carbon dioxide sourced? how is it returned?

Answer 5

CO2 is taken from the atmosphere by plants, bacteria and some protists to be used for photosynthesis
CO2 is returned mainly through decay as an end product of cellular respiration
The cycling of carbon through organisms and the atmosphere is critical to the survival of all organisms

Question 6

what is the inorganic molecule of nitrogen needed for? How is it trapped?

Answer 6

Required by organisms in large amounts because it is a key of all proteins. Atmospheric nitrogen is trapped by certain bacteria and converted into compounds that can be used by plants in nitrogen fixations
Symbiotic bacteria in the roots of some plants such as legumes, she-oaks and acacias do this

Question 7

minerals are inorganic. What are some important ones? where are they found?

Answer 7

phosphorus, potassium, calcium, magnesium, iron, sodium, iodine and sulfur (others in small amounts). Mineral ions are found in cytosol of cells, structures like bones and many enzymes and vitamins

Question 8

what are the ultimate source of organic molecules?

Answer 8

Photosynthetic parts of plants and algae trap and convert light into the simple carbohydrate, glucose. In this way plants and algae are the ultimate source of organic compounds

Question 9

what are the four main types of organic molecules?

Answer 9

carbohydrates, lipids, proteins and nucleic acids

Question 10

how can mammals convert organic compounds into other organic compounds?

Answer 10

units may be linked together to form larger molecules
- other chemical groups may be attached to form things like glycoproteins (proteins with sugars) and phospholipids (lipids with phosphate)

Question 11

how abundant are carbohydrates? what are they important for?

Answer 11

Most abundant organic compounds in nature

Important source of energy

Question 12

what are plants carbohydrates?

Answer 12

• starch used to store energy

- cellulose for structural support

Question 13

what are animals carbohydrates?

Answer 13

• glycogen for energy storage

Question 14

what are carbohydrates made from?

Answer 14

carbon, hydrogen and oxygen

Question 15

what are basic subunits?

Answer 15

simple sugars called monosaccharides (single sugars) eg. Glucose is one made in photosynthesis

Question 16

what do two sugars together form?

Answer 16

disaccharide (two sugars)

Question 17

what is formed when many sugars join together?

Answer 17

they from long chains called polysaccharides (many sugars)

Question 18

what are lipids? what are the needed for? What are two examples? what are they made of?

Answer 18

They are fatty substances that include fats and oils
Fats and oils are important as energy storing molecules
Phospholipids are an important component of cells
Steroids are lipids that act as membrane components, hormones and vitamins
Comprised of carbon, hydrogen and oxygen but in different proportions to carbohydrates. A much smaller amount of oxygen and they contain other elements such as phosphorus and nitrogen

Question 19

how do proteins compare to other organic molecules? How many are there? What can they form?

Answer 19

More complex than carbohydrates or lipids
Thousands and their functions vary
Each organism has unique proteins unlike lipids and carbohydrates
Some form structural components of cells and are enzymes, hormones or carrier molecules (haemoglobin etc)

Question 20

what are proteins made of? What are amino acids?

Answer 20

All have carbon, hydrogen, oxygen and nitrogen. Many have sulfur, phosphorus and others
Composed of chains of smaller subunits called amino acids
Amino acids in proteins are linked by a kind of chemical bond called a peptide bond and proteins are called polypeptides or peptide chains

Question 21

What are nucleic acids? What the two different types? What are both made of?

Answer 21

They are genetic material of all organisms and determine many features or the organism
There are two types:
- DNA (deoxyribonucleic acid)
- RNA (ribonucleic acid)
- both are made of long chains of subunits called nucleotides

Question 22

what are vitamins needed for? how can vitamins be sourced?

Answer 22

Required by animals in small amounts for functioning

Animals can synthesise some vitamins but others must be obtained. Important as they are needed to make some enzymes