Lecture 2 - atoms, bonds, and molecules

Question 1

What is DNA used for?

Answer 1

identification and analysis

Question 2

how are bacteria and viruses killed?

Answer 2

denaturing proteins

Question 3

atom

Answer 3

smallest particle of an element

-made up of electrons (e-), protons (p+), neutrons (n0)

Question 4

what makes up a nucleus

Answer 4

protons and neutrons

Question 5

atomic number

Answer 5

made up of how many protons and neutrons

Carbon atomic number is 6 therefore it has 6 protons and 6 neutrons

Question 6

what determines the different elements?

Answer 6

number of protons

carbon - 6
nitrogen - 7

Question 7

molecule

Answer 7

two or more atoms (N2)

Question 8

compound

Answer 8

molecule formed from two or more different elements (C6H12O6)

Question 9

what are compounds help together by?

Answer 9

chemical bonds

Question 10

covalent bonds

Answer 10

sharing of electrons between atoms

• Strongest and most common
• formed between C, H, O, N, S and P

Question 11

Ionic Bonds

Answer 11

Complete transfer of electrons from one atom to another

• atoms separate into charged particles (ions)
  1) cations (positive)
  2) anions (negative)

Question 12

what are electrolytes

Answer 12

ionic molecules that dissolve to form ions in solution

Question 13

polar molecules

Answer 13

unequal sharing of electrons

• water: oxygen has more electrons than hydrogen (O= more negative)
• needed to be water soluble

Question 14

hydrogen bond

Answer 14

weak

• usually between H-O or H-N
• between dna base pairs

Question 15

non-polar molecules

Answer 15

neutral molecules with equal electron sharing

• in cells they are composed of C-H
• fats and oils
• stable

Question 16

hydrophilic

Answer 16

attract water

Question 17

hydrophobic

Answer 17

repel water (non-polar)

Question 18

amphipathic

Answer 18

hydrophilic and hydrophobic properties

soap, phospholipids

Question 19

Is DNA positive or negatively charged?

-why is this good?

Answer 19

• negatively charged (polar)

- water loves DNA because positive H on water is attracted to the negative part of DNA

Question 20

phospholipids

Answer 20

amphipathic molecules (polar head (hydrophilic) and non-polar tail (hydrophobic))

Question 21

Acidic solutions

Answer 21

when a component dissolved in water (acid) releases excess hydrogen ions (H+)

Question 22

Basic solutions

Answer 22

when a component dissolved in water releases excess hydroxide ions (OH-)

Question 23

pH scale

Answer 23

measures acid and base concentrations by detecting H+ levels

-0 (acidic), 7 (neutral = equal number of H+/OH-), 14 (basic)

pH=-log[H+]
ex) 0.1 = 10^-1 [H+] = pH 1 = 10^-13 [OH-}