Biology unit 2

Question 1

The number of protons in an atom determines the _____-.

Answer 1

element

Question 2

Atoms are electrically ______ because they have the same number of protons and electrons.

Answer 2

neutral

Question 3

The number of hydrogen atoms in 6NH 3 is _____.

Answer 3

18

Question 4

The atomic mass of an element whose atoms consist of eight protons, nine neutrons, and eight electrons is:

1. 8
2. 16
3. 17
4. 25

Answer 4

17

Question 5

According to the text, how many elements have been identified?

1. 20
2. 92
3. 112
4. 118

Answer 5

118

Question 6

Lavoisier proposed that all matter is composed from the same _____.

1. atoms
2. elements
3. molecules
4. gases

Answer 6

elements

Question 7

Many gases exist as _____ molecules of an element.

Answer 7

diatomic

Question 8

True or False. The symbol Na + represents a sodium atom that has lost an electron.

Answer 8

True

Question 9

True or False. A substance that releases hydrogen ions in water is a base.

Answer 9

False

Question 10

Atoms that form compounds are held together by chemical bonds. The bond that includes sharing electrons with another atom is called _____.

Answer 10

covalent

Question 11

Atoms which transfer electrons can combine to form a(n) ______ bond.

Answer 11

Ionic

Question 12

Choose the three types of bonds introduced.

1. ionic
2. molecular
3. compound
4. covalent
5. hydrogen
6. oxygen

Answer 12

1. Ionic
2. Covalent
3. Hydrogen

Question 13

True or False. Water can dissolve only inorganic compounds.

Answer 13

False

Question 14

From your knowledge about the distribution of electrons in the levels and from the atomic number (in parentheses), indicate the most likely charge on the ion when this atom forms an ion. (Remember the 2, 8, 18 level distribution.)

Oxygen (8)

1. 0
2. -1
3. +1
4. -2
5. +2

Answer 14

4. -2

Question 15

From your knowledge about the distribution of electrons in the levels and from the atomic number (in parentheses), indicate the most likely charge on the ion when this atom forms an ion. (Remember the 2, 8, 18 level distribution.)

Magnesium (12)

1. 0
2. -1
3. +1
4. -2
5. +2

Answer 15

+2

Question 16

When electrons are shared, the type of bonding is called:

1. ionic
2. nuclear
3. hydrogen
4. covalent

Answer 16

Covalent

Question 17

An atom with six electrons in its n = 2 shell will become an ion with a charge of:

1. • 6
2. • 6
3. • 2
4. • 2

Answer 17

4. • 2

Question 18

The heat needed for chemical reaction to take place is called _____.

1. heat of reaction
2. activation energy
3. friction

Answer 18

2. Activation energy

Question 19

Substances which maintain a body’s pH within narrow limits are called ______.

Answer 19

Buffers

Question 20

What is expected when reactants break bonds?

1. energy output
2. energy input
3. equilibrium
4. exchange reaction

Answer 20

1. Energy output

Question 21

True or False. A plant must supply energy through photosynthesis in order for its complex starch molecules to turn to simple sugar.

Answer 21

False

Question 22

True or False. Carbohydrates are converted to energy by the process of hydrolysis.

Answer 22

True

Question 23

True or False. Of the three lipid types, phospholipids are more similar to fats.

Answer 23

True

Question 24

True or False. All proteins carry the genetic codes which determine the structure and function of an organism.

Answer 24

False

Question 25

The most abundant sources of carbohydrates are:

1. vegetables
2. butter
3. beef
4. fish

Answer 25

Vegetables

Question 26

Lipids are chemically most similar to:

1. carbohydrates
2. nucleic acids
3. proteins
4. amino acids

Answer 26

Carbohydrates

Question 27

Enzyme, antibody, hormone, and muscle are roles played by:

1. carbohydrates
2. proteins
3. lipids
4. nucleic acids

Answer 27

Lipids

Question 28

Bonds between amino acids are what type bonds?

1. covalent
2. peptide
3. hydrogen
4. ionic

Answer 28

Peptide

Question 29

The largest molecules in organisms are:

1. carbohydrates
2. proteins
3. lipids
4. nucleic acids

Answer 29

4. Nucleic acids

Question 30

Which organic compound has this component?

sugars

1. carbohydrates
2. lipids
3. nucleic acids
4. proteins

Answer 30

Carbohydrates

Question 31

Which organic compound serves this function?

enzymes

1. carbohydrates
2. lipids
3. nucleic acids
4. proteins

Answer 31

Proteins

Question 32

Which organic compound serves this function?

insulation against cold

1. carbohydrates
2. lipids
3. nucleic acids
4. proteins

Answer 32

Lipids

Question 33

Which organic compound serves this function?

antibodies

1. carbohydrates
2. lipids
3. nucleic acids
4. proteins

Answer 33

Proteins

Question 34

Which organic compound serves this function?

genetic code

1. carbohydrates
2. lipids
3. nucleic acids
4. proteins

Answer 34

Nucleic acids

Question 35

Which organic compound has this component?

DNA

1. carbohydrates
2. lipids
3. nucleic acids
4. proteins

Answer 35

Nucleic acids

Question 36

Which organic compound serves this function?

most highly concentrated energy

1. carbohydrates
2. lipids
3. nucleic acids
4. proteins

Answer 36

Lipids

Question 37

Which organic compound has this component?

fats

1. carbohydrates
2. lipids
3. nucleic acids
4. proteins

Answer 37

Lipids

Question 38

True or False. Many elements bond to carbon by exchanging electrons.

Answer 38

False

Question 39

When compounds which are formed from ionic bonds decompose, the products:

1. are usually atoms of the original reactants
2. are usually simple molecules
3. are usually ions of the original elements
4. are usually of no further chemical value

Answer 39

3. Are usually ions of the original elements

Question 40

Large organic molecules which are synthesized from multiple identical subunits are:

1. carbohydrates
2. polymers
3. proteins
4. nucleic acids
5. all of the above

Answer 40

5. All of the above

Question 41

True or False. Lipids are composed of the same basic elements as carbohydrates.

Answer 41

True

Question 42

Steroids are:

1. complex carbohydrates
2. lipids
3. a subclass of fats
4. a type of phospholipids

Answer 42

Lipids

Question 43

Carbon forms _____ bonds.

Answer 43

Covalent

Question 44

The largest organic molecules are _____.

Answer 44

Nucleic acids

Question 45

True or False. Enzyme molecules react with reactants to produce substrate molecules.

Answer 45

False

Question 46

True or False. Because enzymes have high specificity, fewer than fifteen are required by any organism.

Answer 46

False

Question 47

True or False. The effect of a catalyst is the reduction of activation energy required to initiate a chemical reaction.

Answer 47

True

Question 48

The substance upon which an enzyme acts is called the ____.

Answer 48

substrate

Question 49

The simplest structured unit of a compound is a(n):

1. electron
2. atom
3. proton
4. molecule

Answer 49

Molecule

Question 50

The atomic mass of an atom with six electrons, eight neutrons, and six protons is:

1. six
2. fourteen
3. eight
4. twenty

Answer 50

Fourteen

Question 51

The number of atoms in a molecule of ammonia 3(NH (3) ) is:

1. three
2. four
3. 8
4. 12

Answer 51

4. 12

Question 52

The weak type of bonding which attracts molecules to molecules is:

1. ionic
2. hydrogen
3. covalent
4. nuclear

Answer 52

Hydrogen

Question 53

An ion which has lost two electrons has a charge of:

1. 0
2. -2
3. +2
4. -6

Answer 53

3. +2

Question 54

A strong acid has a pH approaching:

1. 0
2. 8
3. 5
4. 14

Answer 54

0

Question 55

Acid + base yields salt + water is an example of a(n):

1. synthesis reaction
2. exchange reaction
3. decomposition reaction
4. reversible reaction

Answer 55

2. exchange reaction

Question 56

The energy required to start a chemical reaction is called:

1. a catalyst
2. covalence
3. activation energy
4. reversibility

Answer 56

3. Activation energy