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Flashcards in Chemistry of Life Deck (54)
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1

pH of life

7.2 - 7.4

blood has to be slightly basic to accomodate for carbonic acid

2

What elements is life mostly composed of?

Carbon, oxygen, hydrogen, and nitrogen

3

4 macromolecules and function

Lipids: membranes, hormones, communication

Nucleic acids: store genetic information (can act as catalysts)

Proteins: structure, function, catalyst

Carbohydrates: store energy, indentification

4

Valence shell

Outermost shell of electrons

5

What is the bonding point?

Unpaired valence electrons

6

4 main types of bonds

1. Covalent
2. Polar covalent
3. Hydrogen
4. Ionic

7

Covalent bonds

Shared electrons

8

A single covalent bond has...

2 electrons

9

Nonpolar covalent bonds

electrons are shared equally

electrons are halfway between the two atoms

atoms have no charge

10

Polar covalent bonds

Electrons are not shared equally due to electronegatively

11

Why is water a polar molecule?

Oxygen has high electronegativity that attracts electrons. This gives it a partial negative charge and hydrogen gets a partial positive charge

12

What is CH4?

Methane

nonpolar covalent

13

What is NH3?

Ammonia

14

Electronegativity

chemical property that describes the tendency of an atom to attract electrons

15

What factors affect electronegativity?

Atomic number (# of protons)

Greater positive charge will attract more electrons

16

Label the 3 atoms of life in terms of increasing electronegativity

H, C, O

17

Strength of bonds

Nonpolar covalent are hardest to break (methane, hydrogen)

Polar covalent (water, ammonia)

Ionic bonds (NaCl) are easiest to break

18

Ionic bonds

have full charge

19

-OH functional group

hydroxyl, probably some type of alcohol

20

What does a functional group with oxygen probably indicate?

The molecule is probably polar

This means that it is hydrophilic

21

Hydrophilic substances

can interact with water through their charges

if it has a partial or full charge

22

Hydrophobic substances

cannot interact with water through these partial charges

Ex: hydrocarbons have no charge

23

What drives protein folding?

Interactions between hydrophilic and hydrophobic molecules

24

Where are there hydrogen bonds in the hydrogen atom?

Between two different water molecules

(polar covalent is actually in the molecule)

25

Hydrogen bond

an attractive interaction between polar molecules

Hydrogen bonds to atoms with a high electronegativity

26

What does hydrogen bonding lead to?

Cohesion

High specific heat

27

Cohesion

water can stick to itself

surface tension

28

Why is water's high specific heat important?

It makes a good buffer in temperature which is important for life

29

Adhesion

water can stick to other things

capillary action

30

Why does water expand when it freezes?

the orientation of hydrogen bonds

water molecules are spaced further apart in ice lattice structure (less dense)