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Chapter 3: The Molecules of Cells
This activity contains 60 questions.
Select the hydrocarbon from the following choices.
Which is an organic molecule?
Which element is closely associated with the field of organic chemistry?
Carbon atoms are the most versatile molecular building blocks used by living organisms because _____.
carbon can combine with hydrogen to form hydrocarbons
carbon can form molecules that are straight, branched, or ringed
carbon is the central atom of carbon dioxide, a necessary molecule for photosynthesis
each carbon atom can form up to four covalent bonds with a wide variety of bond angles
Citric acid makes lemons taste sour. Which of the following is a functional group that would cause a molecule such as citric acid to be acidic?
Which of these is found in amines?
Choose the pair of terms that completes this sentence: Hydroxyl is to _____ as _____ is to amine.
carbonyl … carboxyl
alcohol … amino
ketone … amino
aldehyde … ketone
Although the structures of the functional groups important to life vary in chemical structure, they share one thing in common: They _____.
all have at least one double bond
cause the carbon to which they are attached to become an asymmetric carbon, and they convert the molecule to an isomer
all contain oxygen
all are hydrophilic and increase the organic compound's water solubility
Ethanol, propanol, and methanol are three simple alcohols. They can be grouped together because they _____.
all contain a carbonyl group
all share the same functional group, a hydroxyl
are soluble in nonpolar solvents
are soluble in water
The ionized or dissociated carboxyl group may be written as _____.
Choose the pair of terms that completes this sentence about functional groups in organic chemistry: Carboxyl is to _____ as _____ is to base.
acid … carbonyl
acid … amino
base … carbonyl
base … amino
What is the process by which cells link monomers together to form polymers?
In a hydrolysis reaction, _____. In this process, water is _____.
monomers are assembled to produce a polymer … consumed
a polymer breaks up to form monomers … consumed
monomers are assembled to produce a polymer … produced
a polymer breaks up to form monomers … produced
Besides water, most of the mass of a typical cell is present in the form of one of these four categories of macromolecules: _____.
monosaccharides, lipids, polysaccharides, and proteins
nucleic acids, carbohydrates, monosaccharides, and proteins
proteins, DNA, RNA, and steroids
proteins, nucleic acids, carbohydrates, and lipids
Lactose is a disaccharide (two monosaccharides joined together). To metabolize lactose, individuals require an enzyme known as lactase. What is true about this reaction?
The reaction dehydrates the sugar.
The reaction causes reactants to be formed.
The reaction causes bloating in individuals who have the enzyme.
The reaction hydrolyzes the sugar.
Which of the following molecules is a carbohydrate?
Carbohydrates are mainly used in our bodies _____.
for building genetic material
for membrane construction
as structural molecules, such as hair and fingernails
Consider the figure shown below. What one characteristic is shared by sucrose and maltose?
They are monosaccharides.
They all contain fructose.
They are all disaccharides.
They are polysaccharides.
Which of the following is a function of carbohydrates (as a class)?
storing genetic information
cushioning vital organs
When two monosaccharides link to form a disaccharide, the by-product is _____.
cushioning vital organs
storing genetic information
The most common disaccharide is _____.
In the process of converting cornstarch into high fructose corn syrup, one of the first products is _____. Then, enzymes are used to convert some of this product to fructose.
Cellulose is a _____ made of many _____.
protein … amino acids
carbohydrate … fatty acids
polypeptide … monomers
polymer … glucose molecules
Generally, animals cannot digest the linkages between the glucose molecules in cellulose. How then do cows get enough nutrients from eating grass?
They have to eat a lot of grass.
Cows and other herbivores are exceptions and make some cellulose-digesting enzymes in their digestive tracts.
Cows make an enzyme in their saliva that hydrolyzes cellulose.
Microorganisms in their digestive tracts hydrolyze the cellulose to glucose.
In what polysaccharide form do plants store sugar to be available later for energy?
The complex carbohydrate that you are most likely to have eaten recently is _____.
A polysaccharide that we use for storing energy in our muscles and livers is _____.
Which of the following components of a tossed salad will pass through the human digestive tract with the least digestion?
oil (in the dressing)
sugar (in the dressing)
starch (in the croutons)
cellulose (in the lettuce)
A glucose molecule is to starch as _____.
a steroid is to a lipid
a nucleic acid is to a polypeptide
a protein is to an amino acid
a nucleotide is to a nucleic acid
Lipids differ from other large biological molecules in that they _____.
are not truly polymers
do not contain carbon
do not have specific shapes
are much larger
Which is the correct term for compounds that do not mix with water?
Nutritionally, saturated triglycerides are considered to be less healthy than unsaturated triglycerides. Consider the differences between the two molecules shown below. What is one major difference between them?
Saturated triglycerides are liquid at room temperature.
Saturated triglycerides have more hydrogens than unsaturated triglycerides.
Saturated triglycerides have more double bonds than unsaturated triglycerides.
Saturated triglycerides are fats; unsaturated triglycerides are carbohydrates.
A fatty acid containing at least two double bonds is called _____.
Manufacturers make vegetable oils solid or semisolid by _____.
adding chemicals to retard spoilage
chilling and refrigeration
adding animal fats to them
Hydrogenated vegetable oils are more like animal fats than other plant oils. Because they _____ than other plant oils, they can contribute to cardiovascular disease.
contain fewer double bonds
are less soluble in water
contain more double bonds
contain less hydrogen
The lipids that form the main structural component of cell membranes are _____.
Cholesterol belongs to which class of molecules?
Some athletes use anabolic steroids to build their body mass. Why is this considered a problematic practice, especially in adolescents?
Anabolic steroids can prevent bone growth.
Anabolic steroids reduce depression.
Anabolic steroids reduce cancer risk.
Anabolic steroids stimulate the body's production of normal sex hormones.
Tetrahydrogestrinone (THG) is an anabolic steroid. How does it differ from more traditional anabolic steroids that have been used in the past by athletes?
THG poses no long-term health risks.
Using THG avoids detection methods currently employed.
THG was structurally manipulated.
THG does not build noticeable muscle mass.
The ovalbumin in egg white can be classified as which type of protein?
How many different kinds of amino acids are there in most proteins?
Protein molecules are polymers of _____.
amino acid molecules
Which of these is found in amino acids?
The peptide bond is _____.
an ionic bond
a bond between two monosaccharides
a covalent bond
a hydrogen bond
To what does the term
amino acids linked by dehydration synthesis
organic monomers covalently bonded
amino acids linked by hydrolysis
organic molecules linked by dehydration synthesis
Which of the following would be affected when a protein is denatured?
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 proteins have been chemically modified.
The sequence and arrangement of the amino acids differs between the two proteins.
The proteins were made in different locations in the cell.
The proteins were made at different times within the cell.
The formation of a peptide bond is shown below. The bond forms through _____.
a dehydration reaction between the two amino groups of two different amino acids
a hydrolysis reaction between the amino group of one amino acid and the carboxyl group of a second amino acid
a dehydration reaction between the amino group of one amino acid and the carboxyl group of a second amino acid
a hydrolysis reaction between the two amino groups of two different amino acids
Enzyme molecules require a specific shape to perform their catalytic function. Which of the following might alter the protein shape?
changing the concentration of the products
changing the concentration of salt in the environment
cooling the protein
changing the concentration of the reactants
The "primary structure" of a protein refers to _____.
the interactions among two or more polypeptides
coiling due to hydrogen bonding between amino acids
the number and sequence of amino acids
the interactions among the R groups of the amino acids
The alpha helix and pleated sheet represent which level of protein structure?
The overall three-dimensional shape of a single polypeptide is called the _____.
How does a protein's quaternary structure differ from other levels of protein structure?
It involves two or more polypeptide chains.
It depends on interactions among a polypeptide's R groups.
It is described by the sequence of amino acids in a polypeptide chain.
It takes the form of an alpha helix.
Collagen is found in connective tissue, which is a structural component of bones, tendons, and ligament. Collagen has great strength because of its _____ structure.
Which of the following do nucleic acids and proteins have in common?
They are large polymers.
They each consist of four basic kinds of subunits.
Their structures contain sugars.
They are both made of amino acids.
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 _____. Look at the figure carefully.
T … G
A … T
A … C
A … G
How does DNA differ from RNA?
DNA is smaller, RNA is larger.
DNA has a sugar-phosphate backbone, RNA does not.
DNA contains adenine, RNA does not.
RNA contains ribose, DNA does not.
A nucleotide is made of which of the following chemical components? Look carefully at the figure below to determine the answer.
a nitrogenous base, an amino acid, and a phosphate group
a nitrogenous base, an amino acid, and a pentose sugar
a nitrogenous base, a fatty acid, and an amino acid
a nitrogenous base, a phosphate group, and a sugar
A shortage of phosphorus in the soil would make it especially difficult for a plant to manufacture _____.
Lactose tolerance is an adaptation _____.
of the milk enzymes of cows that allow lactose to be more digestible
due to individuals drinking a lot of milk
that was advantageous to individuals after the age of 2
that was not advantageous to humans
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