Bio 126- review

Question 1

This is the science of LIFE or LIVING THINGS.

Answer 1

Biology

Question 2

LEVEL OF ORGANIZATION IN LIVING THINGS (9 LEVELS)

Answer 2

ATOM, MOLECULE, MACROMOLECULE, ORGANELLE, CELL, TISSUE, ORGAN, ORGAN-SYSTEM, ORGANISM.

Question 3

Seven (7) characteristics of LIVING THINGS

Answer 3

1. React to the outside environment
2. Keep their insides constant
3. Can store and use energy
4. Are made of ONE or MORE cells
5. Contain DNA in those cells – and use it to grow
6. Have evolved (come) from other living things
7. Are complex compared with non-living things

Question 4

Subatomic Particles

Answer 4

Protons
Neutrons
Electrons

Many elements are commonly found in living organisms – particularly in the human body.

Question 5

Protons (+)

Answer 5

number given by ATOMIC NUMBER – unique to each and every chemical element!

Question 6

Neutrons (no charge)

Answer 6

included with protons in the mass number or atomic mass (weight) and are part of atom’s central core.

Question 7

Electrons (-)

Answer 7

not solid but negatively-charged field moving around central atomic core. Move in rings or shells – and orbitals within those shells.

Question 8

electrons fill the shells up as follows:

Answer 8

(Inner shell) 2 : 8 : 8: 18 (fourth shell)

Question 9

moving electrons back and forth from shell to shell requires:

Answer 9

Moving to an upper (outer) level (shell) requires more energy and falling back to a lower one releases energy

Question 10

how LEDs (light-emitting diodes) work:

Answer 10

The energy from the supplied electricity boosts electrons up to a higher shell within the substance of the diode but they then fall back, emitting their energy as light of a particular wavelength (colour).

Question 11

In the case of water (H2O)

Answer 11

only two of the hybrid orbitals in the oxygen atom are shared with hydrogen atoms – resulting in a V-shaped molecule for water.

Question 12

Atoms combine to form molecules in a process called

Answer 12

bonding

Question 13

Strong bonds

Answer 13

are formed by the sharing of electrons – as in covalent bonding (either polar or non-polar).

Question 14

Weaker bonds

Answer 14

are formed when electrons are actually transferred from one atom to another – as in ionic bonding – in the formation of ions (Na+ Cl-).

Question 15

Even weaker bonds

Answer 15

are formed between oppositely charged parts of molecules – as in hydrogen bonds.

Question 16

The weakest bonds

Answer 16

are formed from tint electrostatic charges and are called van der Waal’s bonds.

Question 17

WATER

Answer 17

Water is a MOLECULE made of 3 ATOMS – with a V-shape (review slide 14).

Question 18

H – O – H H2O H+ + OH-

If we mix a substance like SALT into WATER – it will make a mixture (SALTY WATER)

Answer 18

The salt actually dissociates due to the ions of water being attracted to the ions of the salt

Question 19

Salty Water consists of:

Answer 19

SALT   =     SOLUTE
WATER    =     SOLVENT
MIXTURE   =     SOLUTION

Question 20

Where the SOLVENT is WATER – we call the solution an

Answer 20

AQUEOUS SOLUTION
(AQUA is Latin = water)

Question 21

Since many things mix (dissolve in) water –

WATER is called the

Answer 21

UNIVERSAL SOLVENT

Question 22

Something that mixes with water is called

Answer 22

HYDROPHILIC (water-loving)

Question 23

Something that does NOT mix with water is called

Answer 23

HYDROPHOBIC (water-hating)

Question 24

Special bonds between the H+ and the OH- parts of water – called

Answer 24

HYDROGEN BONDS – hold them together.

Question 25

This is why water EXPANDS when it freezes - becoming ICE, which is lighter and so FLOATS on water.

Answer 25

When water freezes – hydrogen bonds become rigid and push the two parts slightly further apart.

Question 26

Water has TWO(2) important properties: 

Answer 26

1. It is a HEAT STORE – holding heat well | 2. It shows COHESION – due to hydrogen bonds

Question 27

a "skin" that some insects can walk on.

Answer 27

Cohesion gives water surface tension

Question 28

Although water is chemically H2O - it normally exists in a partly ionized form

Answer 28

It forms two ions: H+ the Hydrogen ion (proton) and the other ion - OH- the Hydroxide ion.

Question 29

This gives rise to ACIDS and BASES

Answer 29

- The Hydrogen ion is said to be ACIDIC | - whereas the Hydroxide ion is BASIC (ALKALINE)

Question 30

acids contain (and give out)

Answer 30

H+ ions (charged particles)

Question 31

bases give out

Answer 31

OH- ions (or accept H+ ions)

Question 32

Pure water itself contains both of these ions in equal amounts

Answer 32

10(to the power of)-7 MOLES (of each)

Question 33

If we increase the number of H+ ions

Answer 33

we get more ACID 

Question 34

If we increase the number of OH- ions

Answer 34

we get more BASIC – or ALKALINE

Question 35

We have a scale that is used to measure the POWER of HYDROGEN called the

Answer 35

pH scale

Question 36

the pH of pure water

Answer 36

7

Question 37

If we INCREASE the ACID (H ions) this decreases the minus number (-7) to (-6 or –5) and so the pH value gets

Answer 37

SMALLER

Question 38

If we increase the BASIC (ALKALINE) part – we do what to the pH value:

Answer 38

INCREASE

Question 39

Living tissues like to stay around what pH

Answer 39

7 – because this is safest – called NEUTRAL.

Question 40

They often contain chemicals which will resist (stop) any change in pH AWAY from pH 7, This is called

Answer 40

BUFFERING

Question 41

The CARBON atom is so important to the basis of life on Earth – that we have a whole branch of chemistry devoted to it – called

Answer 41

ORGANIC CHEMISTRY.

Question 42

For a molecule to be ORGANIC

Answer 42

it MUST have Carbon (C) and Hydrogen (H) together in it – usually covalently bonded together.

Question 43

Carbon has a valency of

Answer 43

4 - meaning that it can bond with four other atoms - as it does in many organic molecules

Question 44

But when 2 carbons are linked - each carbon can only

Answer 44

hold THREE other atoms

Question 45

When several carbon atoms are linked - those away from the ends can only

Answer 45

hold TWO other atoms

Question 46

Because the carbon is in the centre of a tetrahedron - its four arms may not hold the same atoms and can therefore exist as

Answer 46

ISOMERS

Question 47

ISOMERS - MIRROR IMAGE FORMS of each other called

Answer 47

Enantiomers or sterio-isomers.

Question 48

isomeric change can

Answer 48

completely alter how a molecule acts in the living cell.

Question 49

Enantiomers- The left-hand form - is called the

Answer 49

L form

Question 50

Enantiomers- The right-hand form is called the

Answer 50

D form

Question 51

Organic molecules can exist as Enantiomers - left handed or right handed, by how they

Answer 51

rotate polarized light.

Question 52

ALL ORGANIC compounds contain

Answer 52

C and H! | Examples: CH4 , C2H5OH , C6H12O6 etc.

Question 53

Carbon dioxide – CO2 is

Answer 53

is not organic [inorganic]

Question 54

In living things there are FOUR(4) groups of complex organic molecules.

Answer 54

1. CARBOHYDRATES 2. LIPIDS 3. PROTEINS 4. NUCLEIC ACIDS