Chemical level of organisation

Question 1

what is included in an atom?

Answer 1

1. nucleus
   - proton -> positively charged
   - neutron -> neutrally charged
2. electron -> negatively charged

Question 2

what are the 4 main components that make up our body mass?

Answer 2

1. oxygen (65%)
2. carbon (18%)
3. hydrogen (12%)
4. nitrogen (3%)

Question 3

what are isotopes?

Answer 3

in isotopes, atoms of an element have different numbers of neutrons but the same number of protons. Even if they have a different number of neutrons, they will have identical chemical characteristics.

Question 4

what are radioisotopes?

Answer 4

some isotopes have unstable nuclei, and these release radiation. This radiation is used for medical investigations and treatment. (ex. bone scan, thyroid scan…)

Question 5

what is an inert element?

Answer 5

an element with complete shells which dont participate in chemical reactions.

Question 6

what are the types of chemical bonds?

Answer 6

1. ionic bonds (transferred)
2. covalent bonds (shared)
3. hydrogen bonds

Question 7

what’s the difference between polar covalent bonds and nonpolar covalent bonds?

Answer 7

In a nonpolar covalent bond, a pair of electrons is shared equally between 2 atoms, since they share equally, the strength and bond is the strongest.
In a polar covalent bond, a pair of electrons is shared unequally between 2 atoms, since they do not share equally, the strength and bond is weak.

Question 8

What is a carbohydrate?

Answer 8

• an organic compound with Carbon, Hydrogen and Oxygen in a ratio of 1:2:1
• carbohydrates acc for <3% of body weight
• classified into 3 grps: monosaccharides, disaccharides, polysaccharides.

Question 9

what is a monosaccharide?

Answer 9

• has a single sugar unit
• Glucose, Frutose, Galatose (GFG)

Question 10

what is a disaccharide?

Answer 10

• formed by 2 sugar units, must be broken down to provide energy.
• Sucrose = glucose + frutose
  Malatose = glucose + glucose
  Lactose = glucose + galatose

Question 11

what is a polysaccharide?

Answer 11

made up of multiple units of monosaccharides, such as:
-> starch - found in plants, storage form of carbohydrate, used food reserve.
- can be digested by humans.
-> cellulose - structural from of carbohydrate, used to from cell wall
- can be digested by humans.
-> glycogen - found in animals, storage form of carbohydrate,
- found in muscle and liver

Question 12

what are lipids?

Answer 12

-organic compound with Carbon, Hydrogen and Oxygen, insoluble in water (hydrophobic)
- accounts for 12%