Mel Unit 1 Bio Test 3-5

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Which of the following categories includes all others in the list?

polysaccharide
starch
monosaccharide
carbohydrate
disaccharide

carbohydrate

The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are in the a form. Which of the following could amylase break down?

glycogen, starch, and amylopectin

Which of the following statements concerning unsaturated fats is true?

They have double bonds in the carbon chains of their fatty acids.

The structural level of a protein least affected by a disruption in hydrogen bonding is the:

primary level.

Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together. What would happen to DNA molecules treated with these enzymes?

The phosphodiester linkages of the polynucleotide backbone would be broken.

The molecular formula for glucose is C6H12O6 . What would be the molecular formula for a polymer made by linking ten glucose molecules together by dehydration reactions?

C60 H102 O51

Which of the following pairs of base sequences could form a short stretch of a normal double helix of DNA?

5´-ATGC-3´ with 5´-GCAT-3´

Which molecule is a nucleotide?
ATP
Deoxyribose
The amino acid glycine

ATP

Which feature of large biological molecules explains their great diversity?

The many ways that monomers of each class of biological molecule can be combined into polymers

What structural difference accounts for the functional differences between starch and cellulose?

Starch and cellulose differ in the glycosidic linkages between their glucose monomers.

There are four levels of protein structure. These figures show primary, secondary, tertiary, and quaternary protein structure. Which level(s) of protein structure may be stabilized by covalent bonds?

Primary and tertiary levels of protein structure

These figures show the four levels of protein structure: primary, secondary, tertiary, and quaternary structure. Which level of protein structure is characteristic of some, but not all, proteins?

Quaternary level of protein structure

A dehydration reaction (or condensation reaction) is the process in which _____.

water molecules are produced as a polymer is formed from monomers

The four main categories of large biological molecules present in living systems are _____.

proteins, nucleic acids, polysaccharides, and lipids

Molecules with which functional groups may form polymers via dehydration reactions?

either hydroxyl or carboxyl groups

Which of these molecules is not formed by dehydration reactions?

fatty acids

Which of these classes of biological molecules consist of both small molecules and macromolecular polymers?

carbohydrates

Which of the following is not a polymer?

glucose

What is the chemical reaction mechanism by which cells make polymers from monomers?

dehydration reactions

Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?

Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers.

Large organic molecules are usually assembled by polymerization of a few kinds of simple subunits. Which of the following is an exception to this statement?

a steroid

Polysaccharides, triacylglycerides, and proteins are similar in that they

are synthesized from subunits by dehydration reactions.

Dehydration reactions are used in forming which of the following compounds?

triacylglycerides, polysaccharides, and proteins

DNAase is an enzyme that catalyzes the hydrolysis of the covalent bonds that join nucleotides together. What would first happen to DNA molecules treated with DNAase?

The phosphodiester bonds between deoxyribose sugars would be broken

Which of the following is an example of hydrolysis?

the reaction of a fat, forming glycerol and fatty acids with the consumption of water

How many molecules of water are needed to completely hydrolyze a polymer that is 11 monomers long?

10

Sucrose is formed when glucose is joined to fructose by a(n) _____.

glycosidic linkage

Plant cell walls consist mainly of _____.

cellulose

Which of the following polymers contain nitrogen?

chitin

On food packages, to what does the term insoluble fiber refer?

cellulose

Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified?

as a disaccharide

All of the following are polysaccharides except

lactose

Many mammals control their body temperature by sweating. Which property of water is most directly responsible for the ability of sweat to lower body temperature?

the absorption of heat by the breaking of hydrogen bonds

The bonds that are broken when water vaporizes are

hydrogen bonds between water molecules.

Which of the following is a hydrophobic material?

wax

We can be sure that a mole of table sugar and a mole of vitamin C are equal in their

number of molecules.

Measurements show that the pH of a particular lake is 4.0. What is the hydrogen ion concentration of the lake?

10-4 M

What is the hydroxide ion concentration of the lake described in question 5? Hydrogen 10-4

10-10 M

A slice of pizza has 500 kcal. If we could burn the pizza and use all the heat to warm a 50-L container of cold water, what would be the approximate increase in the temperature of the water? (Note: A liter of cold water weighs about 1 kg.)

10°C

How many grams of acetic acid () would you use to make 10 L of a 0.1 M aqueous solution of acetic acid? (Note: The atomic masses, in daltons, are approximately 12 for carbon, 1 for hydrogen, and 16 for oxygen.)

60g

Which property of water allows a paper towel to pick up a puddle of water?

adhesion of water molecules to other kinds of molecules

Which property of water allows dogs to cool themselves by panting?

water's high heat of vaporization

Identify all correct statements about the ionization of water.

-Water ionizes to form hydroxide and hydronium ions.
-Dissociation of water is reversible.
-Dissociation of water produces equal numbers of OH- and H+.

What is the difference between H+ concentration in an acidic solution such as lemon juice (pH 2) and a basic solution such as household bleach (pH 13)?

The H+ concentration of lemon juice is higher than the H+ concentration of household bleach by a factor of 1011 (100 billion).

Water molecules have a polarity, which allows them to be electrically attracted to other water molecules and other polar molecules by weak chemical bonds known as _____.

hydrogen bonds

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

polar covalent bonds.

Sulfur is in the same column of the periodic table as oxygen, but has electronegativity similar to carbon. Compared to water molecules, molecules of H2S

will not form hydrogen bonds with each other.

The slight negative charge at one end of one water molecule is attracted to the slight positive charge of another water molecule. What is this attraction called?

a hydrogen bond

The partial negative charge in a molecule of water occurs because

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

Water molecules are able to form hydrogen bonds with

compounds that have polar covalent bonds.

Many of water's emergent properties, such as its cohesion, its high specific heat, and its high heat of vaporization, result from the fact that water molecules _____.

are attracted to each other by partial negative and positive charges on the oxygen and hydrogen atoms, respectively

The amount of energy that must be absorbed or lost to raise or lower the temperature of 1 g of liquid water by 1°C _____.

is 1 calorie

Because organisms are made primarily of water, they resist rapid temperature changes. This useful quality is based on water's _____.

high specific heat

Sodas typically contain sugar, flavorings, coloring agents, and carbon dioxide dissolved in water. The best term to describe this mixture would be _____.

an aqueous solution

If the molecular mass of a carbon atom is 12, the mass of a hydrogen atom is 1, and the mass of an oxygen atom is 16 daltons, how many molecules does one mole of table sugar (sucrose; C12H22O11) contain?

6.02 x 10^23

Which of the following takes place as an ice cube cools a drink?

Kinetic energy in the drink decreases.

The nutritional information on a cereal box shows that one serving of a dry cereal has 200 kilocalories. If one were to burn one serving of the cereal, the amount of heat given off would be sufficient to raise the temperature of 20 kg of water how many degrees Celsius?

10.0°C

Liquid water's high specific heat is mainly a consequence of the

absorption and release of heat when hydrogen bonds break and form.

Which type of bond must be broken for water to vaporize?

hydrogen bonds

Why does ice float in liquid water?

Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water.

Hydrophobic substances such as vegetable oil are

nonpolar substances that repel water molecules.

One mole (mol) of glucose (molecular mass = 180 daltons) is

both 180 grams of glucose and 6.02 × 1023 molecules of glucose.

Temperature usually increases when water condenses. Which behavior of water is most directly responsible for this phenomenon?

the release of heat by the formation of hydrogen bonds

An acid is a substance that _____.

increases the hydrogen ion concentration of an aqueous solution

A pH of 6 is how many times more acidic than a pH of 9?

1000

Select the statement that best describes a buffer.

A buffer resists change in pH by accepting hydrogen ions when acids are added to the solution and donating hydrogen ions when bases are added.

The element present in all organic molecules is

carbon

The complexity and variety of organic molecules is due to

the chemical versatility of carbon atoms.

The experimental approach taken in current biological investigations presumes that

living organisms can be understood in terms of the same physical and chemical laws that can be used to explain all natural phenomena.

Which of the following people was the first to synthesize an organic compound, urea, from inorganic starting materials?

Friedrich Wohler

When Stanley Miller applied heat and electrical sparks to a mixture of simple inorganic compounds such as methane, hydrogen gas, ammonia, and water vapor, what compounds were produced?

both simple organic compounds and more complex organic compounds such as amino acids and hydrocarbons

Stanley Miller's 1953 experiments supported the hypothesis that

organic molecules can be synthesized abiotically under conditions that may have existed on early Earth.

How many electron pairs does carbon share in order to complete its valence shell?

4

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

covalent

Which of the following statements best describes the carbon atoms present in a seed-eating bird?

They were incorporated into organic molecules by plants, they were processed into sugars through photosynthesis, and they are ultimately derived from carbon dioxide.

Which of the following statements best describes the carbon atoms present in a seed-eating bird?

The carbon atoms ultimately came from carbon dioxide incorporated into sugars through photosynthesis.

How many structural isomers are possible for a substance having the molecular formula ?

2

Which of the following statements correctly describes cis-trans isomers?

They have variations in arrangement around a double bond.

Research indicates that ibuprofen, a drug used to relieve inflammation and pain, is a mixture of two enantiomers; that is, molecules that

are mirror images of one another.

What determines whether a carbon atom's covalent bonds to other atoms are in a tetrahedral configuration or a planar configuration?

the presence or absence of double bonds between the carbon atom and other atoms

Compared to a hydrocarbon chain where all the carbon atoms are linked by single bonds, a hydrocarbon chain with the same number of carbon atoms, but with one or more double bonds, will

be more constrained in structure.

Organic molecules with only hydrogens and five carbon atoms can have different structures in all of the following ways except

by forming enantiomers.

Why are hydrocarbons insoluble in water?

The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages.

A compound contains hydroxyl groups as its predominant functional group. Which of the following statements is true concerning this compound?

It should dissolve in water.

Which two functional groups are always found in amino acids?

carboxyl and amino

Amino acids are acids because they always possess which functional group?

carboxyl

Testosterone and estradiol are male and female sex hormones, respectively, in many vertebrates. In what way(s) do these molecules differ from each other?

Testosterone and estradiol have different functional groups attached to the same carbon skeleton.

A chemist wishes to make an organic molecule less acidic. Which of the following functional groups should be added to the molecule in order to do so?

amino

Which chemical group can act as an acid?

carboxyl

A carbon skeleton is covalently bonded to both an amino group and a carboxyl group. When placed in water it

would function as both an acid and a base.

Which of the following categories includes all others in the list?

carbohydrate

The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are in the a form. Which of the following could amylase break down?

glycogen, starch, and amylopectin

Which of the following statements concerning unsaturated fats is true?

They have double bonds in the carbon chains of their fatty acids.

The structural level of a protein least affected by a disruption in hydrogen bonding is the

primary level.

Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together. What would happen to DNA molecules treated with these enzymes?

The phosphodiester linkages of the polynucleotide backbone would be broken.

Which of the following pairs of base sequences could form a short stretch of a normal double helix of DNA?

5´-ATGC-3´ with 5´-GCAT-3´

Which molecule is a nucleotide?

ATP

Which feature of large biological molecules explains their great diversity?

The many ways that monomers of each class of biological molecule can be combined into polymers

There are four levels of protein structure. These figures show primary, secondary, tertiary, and quaternary protein structure. Which level(s) of protein structure may be stabilized by covalent bonds?

Primary and tertiary levels of protein structure

A dehydration reaction (or condensation reaction) is the process in which _____.

water molecules are produced as a polymer is formed from monomers

The four main categories of large biological molecules present in living systems are _____.

proteins, nucleic acids, polysaccharides, and lipids

Molecules with which functional groups may form polymers via dehydration reactions?

either hydroxyl or carboxyl groups

Which of these molecules is not formed by dehydration reactions?

fatty acids

Which of these classes of biological molecules consist of both small molecules and macromolecular polymers?

carbs

What is the chemical reaction mechanism by which cells make polymers from monomers?

dehydration reactions

Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?

Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers.

Large organic molecules are usually assembled by polymerization of a few kinds of simple subunits. Which of the following is an exception to this statement?

a steroid

Polysaccharides, triacylglycerides, and proteins are similar in that they

are synthesized from subunits by dehydration reactions.

Dehydration reactions are used in forming which of the following compounds?

triacylglycerides, polysaccharides, and proteins

DNAase is an enzyme that catalyzes the hydrolysis of the covalent bonds that join nucleotides together. What would first happen to DNA molecules treated with DNAase?

The phosphodiester bonds between deoxyribose sugars would be broken.

Humans can digest starch but not cellulose because

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

The difference between the sugar in DNA and the sugar in RNA is that the sugar in DNA

contains one less oxygen atom.

If cells are grown in a medium containing radioactive 32P-labeled phosphate, which of these molecules will be labeled?

both phospholipids and nucleic acids

How will brief heating (to 95°C) affect macromolecular structures in aqueous solution?

DNA duplexes will unwind and separate, and proteins will unfold (denature).

Which of the following is not a monomer/polymer pairing?

triglyceride/phospholipid bilayer

If two molecules of the general type shown in the figure were linked together, carbon-1 of one molecule to carbon-4 of the other, the single molecule that would result would be

maltose

Use the following information to answer the question below.

Approximately 32 different monomeric carbohydrate subunits are found in various natural polysaccharides. Proteins are composed of 20 different amino acids. DNA and RNA are each synthesized from four nucleotides.


Among these biological polymers, which has the least structural variety?

DNA

Use the following information to answer the question below.

Approximately 32 different monomeric carbohydrate subunits are found in various natural polysaccharides. Proteins are composed of 20 different amino acids. DNA and RNA are each synthesized from four nucleotides.


Which class of biological polymer has the greatest functional variety?

proteins

The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are the α form. Which of the following could amylase break down?

starch

If cells are grown in a medium containing radioactive 15N, which of these molecules will be labeled?

both proteins and nucleic acids

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