Chapter 3 Questions Flashcards
(119 cards)
1
Q
L-dopa is used to treat _____.
A
Parkinson’s disease
2
Q
What kind of effect does R-dopa have on Parkinson’s disease
A
Nothing
3
Q
Structural isomers
A
differ in the covalent partnerships between their atoms.
4
Q
Geometric isomers
A
vary in arrangement of atoms around a double bond.
5
Q
Enantiomers
A
are molecules that are mirror images of each other, like left and right hands.
6
Q
Enantiomers are molecules that _____.
A
are mirror images
7
Q
Which statement helps most to explain why life is based on carbon compounds?
A) C is very abundant in non-living nature.
B) C-C bonds are as strong as C-O bonds.
C) Each C atom makes three covalent bonds.
D) C makes strong bonds with O
E) All of the above.
A
B) C-C bonds are as strong as C-O bonds.
8
Q
Carbon skeletons may be arranged in rings.
A
TRUE
9
Q
Carbon skeletons only contain double bonds.
A
FALSE
10
Q
Carbon skeletons are always linear and never branched.
A
FALSE
11
Q
The length of carbon skeletons is always the same; it is the attachments that differentiate molecules
A
FALSE
12
Q
Amino Group
A
NH2
13
Q
Carbonyl Group
A
CO
14
Q
Hydroxyl Group
A
HO
15
Q
Carboxyl Group
A
CO2H
16
Q
Sulfhydryl Group
A
HS
17
Q
Phosphate Group
A
PO4
18
Q
Which of the following would bind to a sweet receptor most tightly? grapes malted milk shake milk table sugar
A
grapes
19
Q
About Sucrose
A
(a) It’s a disaccharide.
(b) It contains glucose.
(c) It’s table sugar.
20
Q
Polymers that contain sugars …
A
(a) may store hereditary information.
(b) may store energy.
(c) may protect cells.
21
Q
Unmodified sugars (those with the formula Cn H2n On ) can have …
A
- H covalently bound to the C of a C=O group.
2. the formula C3H6O3
22
Q
A molecule has the formula Cn H2n On . What else does it need to be an unmodified monosaccharide?
A
O bound to every C
23
Q
What is the LEAST that two molecules can differ, and still be called different kinds of sugars?
A
The orientation of an OH group differs.
24
Q
The alpha and beta forms of glucose, found in starch and cellulose, differ in …
A
how one of the -OH groups is oriented.
25
What happens when glucose forms a ring?
The molecule loses its carbonyl group.
26
Sugar can be found in ...
(a) ATP.
(b) DNA.
(c) starch.
27
A sugar can have ...
H covalently bound to the C of a C=O group.
28
A molecule with the formula C6H12O6 is _____.
possibly glucose or fructose
29
An organic molecule can have many functional groups.
True
30
Organic molecules are only made by living organisms.
False
31
Some organic molecules contain carbon atoms; others do not.
False
32
Polymers are always made of monomers.
True
33
Polymers' synthesis generally consumes water.
False
34
Polymers are always made by condensation reactions.
False
35
Polymers are often made by a hydrolysis process.
False
36
The organic molecule called DNA is an example of ....
a polymer made of nucleotides.
37
Dehydration reactions _____. They do so by _____.
link monomers to form a polymer ... removing a water molecule
38
The reaction that joins two monomers to form a polymer is known as a _____ reaction. The molecule of water formed is due to the interaction between _____ and a hydrogen ion.
dehydration ... a hydroxyl group
39
What does the term amino acid signify about the structure of the molecule?
It consists of an amino group and a carboxyl group.
40
Glycogen is _____.
a polysaccharide found in animals
41
glucose + glucose —> _____ by _____.
maltose + water ... dehydration synthesis
42
```
Which of these is a source of lactose?
starch
sugar beets
milk
sugar cane
potatoes
```
milk
43
```
Which of these is a polysaccharide?
lactose
sucrose
glucose
cellulose
galactose
```
cellulose
44
_____ is the most abundant organic compound on Earth.
Cellulose
45
Cellulose is ...
made with glucose that has the beta ring form.
46
Glycogen ...
occurs in animal cells and has branches.
47
Which fact is most important in explaining why cellulose is a better structural material than starch?
A. Links between alpha glucoses
are stronger than links between beta glucoses.
B.Branched polymers can form more hydrogen bonds than unbranched polymers.
C. Alpha-linkages make it easier for the polymer to coil into a helix.
D. C-C links are stronger than C-O-C links.
E. Polymers made of fructose are stronger than polymers made of glucose.
C. Alpha-linkages make it easier for the polymer to coil into a helix.
48
A cotton shirt is chemically most similar to a ...
sugar cube.
49
A polysaccharide called starch consists entirely of glucose molecules. During early stages of starch digestion, starch would be broken down into _____.
maltose
50
```
Which of the following foods would contain the most starch?
liver
steak
carrots
celery
```
carrots
51
What do fats, steroids, and waxes have in common?
Low solubility in water.
52
Dr. Haxton told one of his students, "To move in the bloodstream, fats need the help of phospholipids." What would a good student say?
Yes. Nonpolar molecules aren't compatible with water.
53
The presence of many C-C and C-H bonds causes fats to be ...
(a) rich in energy.
| (b) insoluble in water.
54
The head of a fat is ...
glycerol.
55
In fat synthesis,________and fatty acids combine to make fats plus________.
glycerol; water
56
In the reaction that builds a fat,________ groups react with ________ groups.
hydroxyl; carboxyl
57
Fats vary with respect to the number of ...
(a) hydrocarbon tails.
(b) C atoms in the tails.
(c) double bonds in the tails.
58
A food company hydrogenated a barrel of fat. The treatment ...
made the fat less fluid.
59
The most unsaturated fats have ...
the most double bonds.
60
What do DNA, proteins, and fats have in common?
They contain carbonyl groups.
61
```
Which of the following foods contain(s) fats that would have at least one double bond in their carbon skeleton?
peanuts
eggs
lard
margarine
```
peanuts
62
The oil and vinegar in your salad dressing remain separate from one another due to the _____ properties of the oil.
hydrophobic
63
```
Which of these is NOT a lipid?
cholesterol
wax
RNA
phospholipid
steroids
```
RNA
64
```
Which of these is rich in unsaturated fats?
beef fat
lard
a fat solid at room temperature
olive oil
butter
```
Olive oil
65
A function of cholesterol that does not harm health is its role _____.
as a component of animal cell membranes
66
Phospholipids are most important for ...
preventing leakage from cells.
67
To find the best source of phospholipids, look at ...
membranes.
68
What do phosphoglycerides and fats have in common?
Ester linkages.
69
Phospholipids' synthesis uses fatty acids.
True
70
Some phospholipids' tails have double bonds.
True
71
Phospholipids all ionize.
True
72
Which fact is most important in causing phospholipids to behave as they do in water?
(A) Water molecules make hydrogen bonds.
(B) Hydrogen is more electronegative than oxygen.
(C) Nonpolar groups repel water.
(D)Phosphate groups can bind together.
(E) Hydrocarbons attract one another.
(A) Water molecules make hydrogen bonds.
73
In a membrane, the________of the phospholipids in one monolayer face the________of the phospholipids in the other monolayer.
tails; tails
74
It is difficult for molecules to pass through the phospholipid bilayer because ...
polar molecules attract one another.
75
```
Which lipid is most amphipathic?
Phospholipid
Cholesterol
Triglyceride
Wax
Fat
```
Phospholipid
76
What do phospholipids and cholesterol have in common?
Both are important components of cell membranes.
77
What does cholesterol have in common with sex hormones?
Four linked rings.
78
or good health, you don't want your body to run the LDL faster than the HDL part because ...
LDL cholesterol is stored; HDL cholesterol is destroyed.
79
Anabolic steroids are prescribed to _____.
people who suffer from muscle-debilitating diseases
80
The ovalbumin in egg white can be classified as which type of protein?
storage
81
How many different kinds of amino acids are there in most proteins?
20
82
Protein molecules are polymers of _____.
amino acid molecules
83
```
Which of these is found in amino acids?
R-NH2
R-OH
R-COH
R-PO4 2
```
R-NH2
84
The peptide bond is _____.
a covalent bond
85
To what does the term polypeptide specifically refer?
amino acids linked by dehydration synthesis
86
```
Which of the following would be affected when a protein is denatured?
amino groups
primary structure
tertiary structure
side chains
```
tertiary structure
87
Two proteins have the same number and type of amino acids. How is it that they can have different shapes and therefore different functions?
The sequence and arrangement of the amino acids differs between the two proteins.
88
A peptide bond forms through
a dehydration reaction between the amino group of one amino acid and the carboxyl group of a second amino acid
89
Enzyme molecules require a specific shape to perform their catalytic function. Which of the following might alter the protein shape?
changing the concentration of salt in the environment
90
The "primary structure" of a protein refers to _____.
the number and sequence of amino acids
91
The alpha helix and pleated sheet represent which level of protein structure?
secondary structure
92
The overall three-dimensional shape of a single polypeptide is called the _____.
tertiary structure
93
How does a protein's quaternary structure differ from other levels of protein structure?
It involves two or more polypeptide chains.
94
Collagen is found in connective tissue, which is a structural component of bones, tendons, and ligament. Collagen has great strength because of its _____ structure.
quaternary structure
95
Which of the following do nucleic acids and proteins have in common?(A) They are large polymers.
(B) Their structures contain sugars.
(C) They each consist of four basic kinds of subunits.
(D) They are both made of amino acids.
(A) They are large polymers.
96
Based on the way the nitrogen-containing bases in DNA and RNA pair, you would expect the percentage of _____ to be equal to the percentage of _____.
A ... T
| C ... G
97
How does DNA differ from RNA?
RNA contains ribose, DNA does not.
98
A shortage of phosphorus in the soil would make it especially difficult for a plant to manufacture _____.
DNA
99
Lactose tolerance is an adaptation _____.
that was advantageous to individuals after the age of 2
100
When calorie intake is low, proteins are the last resource the body uses for fuel. Which statement below gives the best reason for this?
(A) Proteins produce little usable energy when metabolized.
(B) When the body uses proteins as fuel, it is breaking down substances vital to its structure and essential functions.
(C) There are few proteins in the body.
(D) We ingest a very small amount of protein every day.
(B) When the body uses proteins as fuel, it is breaking down substances vital to its structure and essential functions.
101
```
Which condition is irrelevant, to some extent, to the maintenance of protein structure in your body?
salt concentration
body temperature
environmental temperature
pH level
```
environmental temperature
102
Which statement correctly describes bonds of the secondary structure of proteins?
(A) Secondary structure involves the association of polypeptide chains, or subunits.
(B) Secondary structure involves bonding between atoms of the R groups of the amino acid subunits.
(C) Disulfide bridges form at the secondary level.
(D) Secondary structure involves hydrogen bonding between atoms of the polypeptide backbone.
(D) Secondary structure involves hydrogen bonding between atoms of the polypeptide backbone.
103
When an RNA strand forms using DNA as a template, _____.
uracil pairs with adenine and cytosine pairs with guanine
104
Linus Pauling made significant contributions to our understanding of enzyme structure and chemical bonding. However, his theory regarding DNA was wrong because he proposed that _____.
DNA consists of a triple helix structure
105
DNA nucleotides are composed of _____.
deoxyribose sugars, which are bonded to a phosphate group and a nitrogenous base
106
Lactase deficiency is more common in Asian, Native American, Mediterranean and some African populations than it is among people with northern or western European ancestry. How would you explain why this is so?
Although most mammals, including humans, are not able to digest the milk sugar, lactose, after infancy, the ancestors of northern and western Europeans relied on dairy products as an important part of their food supply. When other food sources were in low supply, mutations that allowed the expression of the enzyme lactase to persist past childhood conveyed an advantage to adults who were able to include dairy products in their diet.
107
Difference between monsaccharide; polysaccharide
A monsaccharide is a simple sugar containing carbon, hydrogen, and oxygen, in a ratio of 1:2:1; a polysaccharide is a complex molecule composed of three or more monosccharides.
108
Difference between hydrophilic; hydrophobic
Hydrophilic means “water-loving,” or attracted to water; hydrophobic means “water-fearing,” or tending not to interact with water molecules.
109
Difference between nucleotide; nucleic acid
A nucleotide is a compound containing a phosphate group (PO4) a five-carbon ring sugar, and a ring-shaped nitrogen base; a nucleic acid is a very LARGE polymer of nucleotides.
110
Glycogen, starch, and cellulose are
polysaccharides
111
The different shapes and functions of different proteins are determined by
the R groups of the amino acids they contain
112
Most enzymes
are sensitive to changes in temperature of pH
113
The large numbers of carbon-hydrogen bonds in lipids
store more energy than the carbon-oxygen bonds in other organic compounds
114
The most important function of nucleic acids is
storing information related to heredity and protein synthesis
115
What are the storage and quick-energy forms of carbohydrates found in animals, and how are these forms structurally related to each other?
The storage form is glycogen, and the quick-energy form is glucose. Glycogen consists of hundreds of glucose molecules linked in a highly branched chain.
116
How many different kinds of monomers are there in:
Starch?
Proteins?
Nucleic Acids?
Starch, 1
Proteins, 20
Nucleic Acids, 4
117
What compound composes most of the cell membrane?
How is this compound suited to the function of the membrane?
Phospholipid composes most of the cell membrane.
The hydrophobic tails of the phospholipids provide a barrier between the inside and the outside of the cell.
118
Steroids are made up of what type of molecule?
Steroids are lipids.
119
Insects that live on land have a coating of wax on the outer surface of their body. What function might the wax serve for these animals?
Wax serves as a waterproof layer, limiting water loss and preventing insects from
drying out.
