Lecture 2 - atoms, bonds, and molecules Flashcards Preview

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Flashcards in Lecture 2 - atoms, bonds, and molecules Deck (23):
1

What is DNA used for?

identification and analysis

2

how are bacteria and viruses killed?

denaturing proteins

3

atom

smallest particle of an element
-made up of electrons (e-), protons (p+), neutrons (n0)

4

what makes up a nucleus

protons and neutrons

5

atomic number

made up of how many protons and neutrons

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

6

what determines the different elements?

number of protons

carbon - 6
nitrogen - 7

7

molecule

two or more atoms (N2)

8

compound

molecule formed from two or more different elements (C6H12O6)

9

what are compounds help together by?

chemical bonds

10

covalent bonds

sharing of electrons between atoms
*Strongest and most common
-formed between C, H, O, N, S and P

11

Ionic Bonds

Complete transfer of electrons from one atom to another
-atoms separate into charged particles (ions)
1) cations (positive)
2) anions (negative)

12

what are electrolytes

ionic molecules that dissolve to form ions in solution

13

polar molecules

unequal sharing of electrons
-water: oxygen has more electrons than hydrogen (O= more negative)
-needed to be water soluble

14

hydrogen bond

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

15

non-polar molecules

neutral molecules with equal electron sharing
-in cells they are composed of C-H
-fats and oils
-stable

16

hydrophilic

attract water

17

hydrophobic

repel water (non-polar)

18

amphipathic

hydrophilic and hydrophobic properties
(soap, phospholipids)

19

Is DNA positive or negatively charged?
-why is this good?

-negatively charged (polar)
-water loves DNA because positive H on water is attracted to the negative part of DNA

20

phospholipids

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

21

Acidic solutions

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

22

Basic solutions

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

23

pH scale

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-}