Chemistry Of Life

Question 1

What is the atomic number?

Answer 1

The number of protons (above the chemical symbol)

Question 2

What is the atomic mass?

Answer 2

The sum of the number of protons and neutrons

Question 3

What are the masses of the proton, the neutron, and the electron?

Answer 3

Proton and Neutron: 1atomic mass

Electron: negligeable mass

Question 4

Why is it that the atomic mass of most atoms isn’t an interger?

Answer 4

Because of their isomers, which makes them have more or less neutrons

Question 5

What is a covalent bond?

Answer 5

It’s a bond in which two atoms share a pair of electrons.

Question 6

What do you call a molecule made of more than one type of atom?

Answer 6

Compound

Question 7

What is electronegativity?

Answer 7

The force that atoms exert on electrons.

Question 8

What happens when an atom in a covalent bond has stronger electronegativity than the other atom?

Answer 8

The electrons shared in that bond will stay for a longer time close to the said atom.
Unequal sharing of electric charge.

Question 9

What is called a covalent bond in which an atom is more electronegative than the other?

Answer 9

A polar covalent bond

Question 10

What is the strongest bond in Bio 1?

Answer 10

Covalent bonds

Question 11

What are hydrogen bonds?

Answer 11

• Positively charged portion of one molecule has a weak attraction to the negatively charged portion of another molecule (OH attracted to highly electronegative atom)
• H-bonds don’t share electrons
  -Involve hydrogen with either oxygen, nitrogen, fluorine or chlorine

Question 12

Why are H-bonds important for life?

Answer 12

Every being on Earth is held together by H-bonds

Question 13

What are ionic bonds?

Answer 13

• A complete transfer of ele trons

Question 14

What do atoms become when they lose or gain electrons? Be precise.

Answer 14

Ions:
- Cations if they lost electrons
- Anions if they gain electrons

Question 15

What molecules are hydrophilic?

Answer 15

Polar molecules and ionic compounds

Question 16

What molecules are hydrophobic?

Answer 16

Nonpolar molecules

Question 17

What type of molecules usually dissolve in water? Why?

Answer 17

Ionic and polar molecules because of H-bonds

Question 18

Non-polar molecules are also attracted to each other through which bond?

Answer 18

Van der Waals forces

Question 19

Rank all the bonds from the weakest to the strongest.

Answer 19

Van der Waals forces, H-bonds, Ionic bonds and Covalent bonds

Question 20

Why does ice float on water? Explain.

Answer 20

Ice is less dense then liquid water because:

• Each molecule of water forms hydrogen bonds with four other molecules
• These 4 H-bonds increase the space the water molecules take up=> water when freezing

Question 21

What is cohesive strength?

Answer 21

Hydrogen bonds keep water molecules from coming apart

Question 22

What other characteristic does cohesive strength give to water?

Answer 22

A high surface tension (surface of water relatively difficult to puncture

Question 23

What is the solvent of life?

Answer 23

Water

Question 24

How much water composes each living organism?

Answer 24

70%

Question 25

Why is water important for organisms (apart from the fact that it is the solvent of life)?

Answer 25

Chemical reactions in each living organism need a watery environment to happen

Question 26

What substances release H+ when dissolved in water?

Answer 26

Acids

Question 27

What substances release OH- when dissolved in water?

Answer 27

Bases

Question 28

What is a carboxyl group?

Answer 28

-COOH It functions as an acid because: -COOH--» -COO^-+H^+ (releases an H^+)

Question 29

What is an amino group?

Answer 29

Functions as weak base by accepting H^+ -NH2+H^+--» -(NH3)^+

Question 30

10^-1 mol/L of H^+ is less acid then 10^-6 mol/L of H^+. True or False.

Answer 30

False

Question 31

What other properties affect the behavior of molecules?

Answer 31

-Functional groups - Isomers

Question 32

What are functional groups for?

Answer 32

They give specific properties to molecules

Question 33

Name the 7 functional groups.

Answer 33

Hydroxyl, Aldehyde, Keto, Carboxyl, Amino, Phosphate and Sulfhydryl

Question 34

Describe *hydroxyl/alcohol* (Components and properties).

Answer 34

- OH bonded to a C which is attached to a compound - Polar - Links to other molecules by dehydration - Forms H-bonds to dissolve into water - Finish in **-ol**

Question 35

Describe *aldehydes* (Components and properties).

Answer 35

- O has a double bond with a C, which is also attached to an H - C=O is really reactive - Important in building molecules - Important in energy-releasing reactions

Question 36

Describe *ketones* (Components and properties).

Answer 36

-O has a double bond with a C, which is attached to 2 compounds - Important in carbohydrates - Important in energy reactions

Question 37

Describe *ketones* (Components and properties).

Answer 37

- O has a double bond with C, which is attached to 2 compounds - Important in carbohydrates - Important in energy reactions

Question 38

Describe *carboxyl* (Components and properties).

Answer 38

- Acidic - O has a double bond with a C which bonded to an OH and another compound

Question 39

Describe *amino* (Components and properties).

Answer 39

- Basic - N is bonded to 2 H and a compound

Question 40

Describe *phosphate* (Components and properties).

Answer 40

- Negatively charged

Question 41

Describe *Sulfhydryl* (Components and properties).

Answer 41

- S bonded to an H and to a compound - By giving up H, two -SH groups form a disulfide bridge, thus stabilizing protein structure

Question 42

What are *isomers*?

Answer 42

Molecules that have the same chemical formula, but different structural formula

Question 43

What is the difference between **structural** and **optical isomers**?

Answer 43

_Structural_: the atoms are joined differently _Optical_: Mirror image of another molecule

Question 44

What does synthesizing mean?

Answer 44

Making