Chapter 2 - The Chemistry and Energy of Life

Question 1

What is the difference between an element and a molecule?

Answer 1

An element is composed of only one kind of atom; molecules can be composed of more than one kind of atom

Question 2

Which type of bonds or interactions between atoms is the strongest?

Answer 2

Covalent Bonds

Question 3

Covalent bond formation depends on the ability of atoms to do what

Answer 3

Share electrons with other atoms

Question 4

Table salt, NaCl, is electrostatically neutral. When dissolved in water, NaCl does what

Answer 4

dissociates to form Na+ and Cl- ions that interact with water molecules

Question 5

What property of water affect(s) life less than the others?
Cohesiveness
High heat capacity
High heat of vaporization
Hydrogen Bonds
Nearly Colorless

Answer 5

Nearly Colorless

Question 6

The “building blocks” ; of polysaccharides are _____, and these blocks are covalently linked together by _____.

Answer 6

monosaccharides; glycosidic linkages

Question 7

What is true of starch?
It is a straight-chain shaped molecule
It is a polymer of fructose
It is formed by the condensation of simple monosaccharides
The properties of starch are very similar to those of cellulose
It cannot be digested by people

Answer 7

It is formed by the condensation of simple monosaccharides

Question 8

Fatty Acids are

Answer 8

Part of membrane structure

Question 9

Phospholipids differ from triglycerides in that phospholipids

Answer 9

are amphipathic

Question 10

An example of a statement that would receive a bad grade on a biology exam covering the first and second laws of thermodynamics

Answer 10

the total energy of a system is available to do work

Question 11

the synthesis of complex molecules _____ energy, whereas their degradation ______ energy. This synthesis occurs with _____ in entropy

Answer 11

Requires; releases; a decrease

Question 12

Entropy is

Answer 12

related to the disorder or randomness of a system

Question 13

Six most common chemical elements in living organisms

Answer 13

Carbon C
Hydrogen H
Nitrogen N
Oxygen O
Phosphorus P
Sulfur S

Question 14

What can be found in the nucleus

Answer 14

Protons and Neutrons of significant mass

Question 15

Protons

Answer 15

Positively charged

Question 16

Neutrons

Answer 16

No charge, neutral

Question 17

Electrons

Answer 17

Negatively charged

Orbit the nucleus and are of very low mass

Question 18

How many electrons are in each orbital?

Answer 18

First Shell: up to 2 electrons
Second Shell: up to 8 electrons
Third Shell: up to 18 electrons
Fourth and subsequent shells: up to 32 electrons

Question 19

Covalent Bond

Answer 19

Forms when two atoms attain stable electron numbers in their outermost shells by sharing one or more pairs of electrons. EX: H2

Question 20

The number of electrons in the outer shell of a given atom determines what?

Answer 20

how many covalent bonds it can form

Question 21

electronegativity

Answer 21

attractive force that an atomic nucleus exerts on electrons in a covalent bond. Electronegativity depends on how many positive charges it has

Question 22

Bond strength from strongest to weakest

Answer 22

Covalent, ionic, hydrogen, van der waal forces

Question 23

Nonpolar Covalent Bonds

Answer 23

Hydrophobic

Question 24

Polar covalent bonds

Answer 24

When electrons are drawn to one nucleus more than to the other
Hydrophilic

Question 25

Ionic bonds

Answer 25

form as a result of the attraction between ions bearing opposite charges
(between cations and anions) EX: NaCl

Question 26

Cation

Answer 26

Positively charged ion EX: Na+

Question 27

Anion

Answer 27

Negatively charged ion EX: Cl-

Question 28

Hydrogen Bonds

Answer 28

form when slightly electronegative regions of molecules attract slightly electropositive regions of molecules.
play important roles in determining and maintaining the 3D shapes of giant molecules
contributes to several properties of water

Question 29

what are the four major groups of biomolecules

Answer 29

Carbs
Lipids
Proteins
Nucleic Acids

Question 30

What make up most of the macromolecules

Answer 30

molecular subunits called monomers

Question 31

Condensation Reaction (aka dehydration synthesis)

Answer 31

the removal of water links monomers together

EX: formation of triglycerides and the formation of (covalent) peptide bonds during protein synthesis

Question 32

Hydrolysis Reactions

Answer 32

The addition of water breaks a polymer into monomers

EX: Hydrolysis of proteins and fats, sometimes called proteolysis, and lipolysis

Question 33

carbohydrates

Answer 33

CHO

complex carbs serve in energy storage and structure for living organisms.

Question 34

what is the most abundant organic molecule on earth

Answer 34

Cellulose

Question 35

Lipids

Answer 35

CHO

most common units of lipids are triglycerides (contains 3 Fatty acid chains and 1 glycerol)

Question 36

Are fats hydrophobic or hydrophilic

Answer 36

Hydrophobic

Question 37

Phospholipids

Answer 37

amphipathic molecules, that have both hydrophobic and hydrophilic regions.
Especially important in forming membranes, also called phospholipid bilayers.

Question 38

Saturated Fats

Answer 38

Single bonds, straight, solid at room temp, steak fat

Question 39

Unsaturated Fats

Answer 39

Have varying amounts of double bonded carbons (C=C) a

are typically liquids at room temperature

Question 40

what happens when bonds are broken in fats and why?

Answer 40

fats generally have many atoms, and breaking apart the C-C bonds generates lots of potential for energy transfers.

Question 41

Laws of thermodynamics

Answer 41

Energy is neither created nor destroyed.

Useful energy tends to decrease (no physical process or chemical reaction is 100 percent efficient)

Question 42

what are functional groups?

Answer 42

covalently bonded groups of atoms that confer specific properties to biological molecules