Ch 1: Science

Question 1

What is science

Answer 1

• Work with evidence, not proof

- Propose explanations based on what we observe

Question 2

Hypothesis

Answer 2

A statement that might be true

Question 3

Fact

Answer 3

Hypothesis confirmed to extremely High degree

Question 4

Theory

Answer 4

A comprehensive explanation of some aspect of nature that is supposed by a vast body of evidence

Question 5

Element

Answer 5

• defined by the number of protons

- cannot be broken down into other substances

Question 6

Molecule

Answer 6

Two or more atoms held together by chemical bonding

Question 7

Compound

Answer 7

Molecules with 2 or more elements

Question 8

Emergent properties

Answer 8

Properties of a compound that are not just the combination of each elements’ properties
Life is an emergent property of a particular arrangement of certain molecules

Question 9

Polar molecule

Answer 9

Molecule with uneven distribution of charges

Question 10

Hydrogen bond

Answer 10

Weak attraction between polar molecules

Question 11

Crystal

Answer 11

3D lattice of atoms

Question 12

Homogenous mixture or solution

Answer 12

Each component cannot be distinguished with a light microscope

Question 13

Enzyme

Answer 13

• catalyst

- makes a chemical reaction take place more easily

Question 14

Diffusion

Answer 14

Net movement of a substance from an area of high concentration to an area of low concentration

Question 15

Osmosis

Answer 15

Diffusion of water across a semi-permeable membrane

Question 16

Acid

Answer 16

• substance that increased concentration of H+ ions in water

- Acidity: Concentration of H+ ions

Question 17

Base

Answer 17

• Substance that increases the concentration of hydroxide (OH-) ions in water

Question 18

Acidity of water

Answer 18

H2O = H+ + OH-

Question 19

pH

Answer 19

Below 7 : acid
7 : neutral
More than 7: base

Question 20

Polymer

Answer 20

Large molecule composed of many repeated subunits

Question 22

4 classes of biologically important macromolecules (large molecules)

Answer 22

Lipids
Carbohydrates
Nucleic acids
Proteins

Question 23

Lipids

Answer 23

Non-polar
High in chemical energy
Ex: fat, oil, wax, phospholipid bilayers

Question 24

Carbohydrates

Answer 24

Polar
High in chemical energy

• Monosaccharides: each molecule has a single sugar unit (glucose, fructose)
• Disaccharides: each molecule has two sugar units (sucrose, lactose)
• Polysaccharides: many sugar units (starch, cellulose, glycogen)

Question 25

Proteins

Answer 25

• Enzymes, hormones, structural proteins
• Folded chain of amino acids (unfolded = polypeptide)
• some parts polar some parts non-polar
• Primary structure: the sequence of amino acids
• Secondary structure: repeated coils or folds of the primary structure
• Tertiary structure: irregular folding of the primary and secondary structures
• Quaternary structure (not always present): two or more tertiary structures integrated into a functional unit

Question 26

Nucleic acids

Answer 26

DNA, RNA

Polymers of nucleotides

Question 27

Living matter elements

Answer 27

96% C, O, N, H

4% Ca, P, K, S, Na…