Quizzes Review

Question 1

About 25 natural elements are known to be essential to life. Which 4 of these 25 elements make up approximately 96% of living matter?

Answer 1

Carbon, Hydrogen, Nitrogen, Oxygen

Question 1

An atom of potassium (K) has an atomic number of 19. This means it always has ______.

Answer 1

19 protons

Question 2

Atoms have no electric charge because they have ________.

Answer 2

equal number of protons and electrons

Question 3

What is the difference between covalent bonds and ionic bonds?

Answer 3

Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between charged ions.

Question 4

Bonds between two atoms that are equally electronegative are ________.

Answer 4

nonpolar covalent bonds

Question 5

An atom that has 10 total electrons would be considered __________.

Answer 5

inert

Question 6

full electrons shells and do not form chemical bonds

Answer 6

inert

Question 7

don’t have full electron shells and form bonds

Answer 7

reactive

Question 8

Which are compounds? H2O, CH4, O2

Answer 8

H2O and CH4

Question 9

Which of the following describes an ion of chlorine: Cl- ? Anion or cation

Answer 9

An anion because it gained one electron.

Question 10

A covalent chemical bond is one in which ________.

Answer 10

outer-shell electrons of two atoms are shared so as to satisfactorily fill their respective orbitals

Question 11

If the cytoplasm of a cell is at pH 7, and the mitochondrial matrix is at pH 8, then the concentration of H+ ions ________.

Answer 11

is 10 times higher in the cytoplasm than in the mitochondrial matrix

Question 12

In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by ________.

Answer 12

polar covalent bonds

Question 13

Water molecules can form hydrogen bonds with ________.

Answer 13

compounds that have polar covalent bonds

Question 14

Cause of a raft spider can walk across the surface of a small pond

Answer 14

surface tension

Question 15

A solution with a pH of 2 has how many more protons in it than a solution with a pH of 4?

Answer 15

100 times more

Question 16

Why does A lake heats up more slowly than the air around it.

Answer 16

bc water has a high specific heat

Question 17

The partial negative charge in a molecule of water occurs because ________.

Answer 17

the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus

Question 18

Consider the following, which represents the structural formula for carbon dioxide.

  O=C=O

Each line in the covalent bonds connecting carbon and oxygen in carbon dioxide represents ________.

Answer 18

a pair of shared electrons

Question 19

The complexity and variety of organic molecules are due to ________.

Answer 19

chemical versatility of carbon atoms

Question 20

In an ethane (C2H6) molecule, each carbon atom is bonded to ________ hydrogen atoms.

Answer 20

3

Question 21

Glucose, fructose and galactose are all simple sugars with the same chemical formula: C6H12O6. What kind of isomers are these?

Answer 21

structural isomers

Question 22

A compound contains hydroxyl groups as its predominant functional group. Therefore, this compound ________. (with water)

Answer 22

dissolve in water

Question 23

A carbon atom is most likely to form what kind of bond(s) with other atoms?

Answer 23

covalent

Question 24

Differences among organisms are caused by differences in the ________.

Answer 24

types and relative amounts of organic molecules synthesized by each organism

Question 25

Humans can digest starch but not cellulose because

Answer 25

humans have enzymes that can hydrolyze the α-glycosidic linkages of starch but not the β-glycosidic linkages of cellulose

Question 26

What makes lipids/fats hydrophobic?

Answer 26

presence of nonpolar C-H bonds

Question 27

summarize the relationship between dehydration reactions and hydrolysis?

Answer 27

Dehydration reactions assemble polymers; hydrolysis reactions break polymers apart.

Question 28

what is in the class of molecules known as nucleotides?

Answer 28

a nitrogenous base, a phosphate group, and a sugar

Question 29

How do phospholipids interact with water molecules?

Answer 29

The polar heads interact with water; the nonpolar tails do not.

Question 30

Polymers of glucose

Answer 30

Starch and cellulose

Question 31

Cooking oil and gasoline (a hydrocarbon) are not amphipathic molecules because they ________.

Answer 31

do not have a polar or charged region

Question 32

Which of the following is a major difference between RNA and DNA?

Answer 32

The type of sugar

Question 33

Which polysaccharide is an important component in the structure of many animals and fungi?

Answer 33

chitin

Question 34

If you disrupt all hydrogen bonds in a protein, then what level of structure will be preserved?

Answer 34

primary

Question 35

What is NOT a component of an amino acid?

Answer 35

phosphate group

Question 36

The process by which a protein’s three-dimensional structure breaks down is referred to as _____.

Answer 36

denaturation

Question 37

What component of amino acid structure varies among different amino acids?

Answer 37

R-group

Question 38

A tripeptide has ________.

Answer 38

three amino acids and two peptide bonds

Question 39

You have just sequenced a new protein found in mice and observe that sulfur-containing cysteine residues occur at regular intervals. What is the significance of this finding?

Answer 39

Cysteine residues are involved in disulfide bridges that help form tertiary structure.

Question 40

The relation between an amino acid and a polypeptide is similar to the relation between ________.

Answer 40

nucleotide and nucleic acid

Question 41

What is necessary to stipulate the 3-D shape of a protein?

Answer 41

the sequence of amino acids in the polypeptide chain

Question 42

In bacteria, DNA will be found in which of the following?

Answer 42

nucleoid

Question 42

Examination of a cell by electron microscopy reveals a high density of ribosomes in the cytoplasm. This observation suggests that this cell is actively producing large amounts of which of the following molecules?

Answer 42

proteins

Question 43

What do both prokaryotic cells and eukaryotic cells do with their genetic info?

Answer 43

store in DNA

Question 44

What domains of life are classified as prokaryotes?

Answer 44

Bacteria and Archaea

Question 45

What structure is common in both plant and animal cells?

Answer 45

mitochondria

Question 46

Major different between prokaryotic and eukaryotic cells?

Answer 46

Eukaryotic cells have membrane-bound organelles, prokaryotic cells do not

Question 47

Tay-Sachs disease is a human genetic abnormality that results in cells accumulating and becoming clogged with very large, complex, undigested lipids. Which cellular organelle is most likely defective in this condition?

Answer 47

lysosomes

Question 48

What makes rough endoplasmic reticulum rough?

Answer 48

covered with ribosomes