Chapter 3 The Molecules of Cells

Question 1

Most of the worlds population cannot digest milk based foods. They are A. because they lack the enzyme B. (a protein). Biological molecules such as proteins, lipids, carbohydrates, and nucleic acids are important to functioning living organisms.

Answer 1

A Lactose intolerant B. lactase

Question 2

Diverse molecules found in cells are composed of A. bonded to other elements. Carbon based molecules are called B. By sharing C. in covalent bonds carbon can bond to D. other atoms. By doing so it can branch in up to E directions. A molecules shape often determines its F.

Answer 2

A. Carbon B. Organic Compounds C. Electrons D. Four E. Four F. Function

Question 3

Methane (CH4) is one of the simplest organic compounds.. Four covalent bonds link four A. atoms to the carbon atom. Each of the four lines in the formula for methane represents a pair of shares B.

Answer 3

A. Hydrogen B. Electrons

Question 4

Methane and other compounds composed of only carbon and hydrogen are called A. Carbon with attached Hydrogen’s can bond together in chains of various B. A chain of carbon atoms is called a C. They can be branched or un branched. therefore different compounds with the same molecular formula can be produced. these structures are called D.

Answer 4

A. Hydrocarbons B. Length C. Carbon Skeleton D. Isomers

Question 5

A organic compound has unique properties that depend upon A. Of the molecule and the B. Attached to it. A functional group of affects a biological molecules function in a characteristic way to keep. Most compounds containing functional groups are hydrophilic C.. This means that they are soluble in water, which is a necessary prerequisite for their roles in water based life.

Answer 5

A. Size and shape B. Groups of Atoms C. Water loving

Question 6

The functional groups are A. Consists of a hydrogen bonded to a oxygen. B. Carbon linked by a double bond to an oxygen atom. C. Consists of a carbon double bonded to both an oxygen and a hydroxyl group. D. Composed of the nitrogen bonded to two hydrogen atoms and the carbon skeleton. E. Consists of a phosphorus Atom bonded to four oxygen atoms. F. A carbon added to three hydrogens.

Answer 6

A. Hydroxyl group B. Carbonyl group C. Carboxyl Group D. Amino Group E. Phosphate Group F. Methyl Group

Question 7

An example of similar compounds that differ only in functional groups is sex hormones
The differences cause varied molecular actions
Male and female sex hormones differ only in A.
The result is distinguishable features of males and females.

Answer 7

A. Functional Groups

Question 8

There are four classes of biological molecules

A. B. C. D.

Answer 8

A. Carbohydrates B. Proteins C. Lipids D. Nucleic Acid

Question 9

The four classes of biological molecules contain very large molecules
They are often called A. because of their large size. They are also called B. because they are made from identical building blocks strung together
The building blocks are called C. A cell makes a large number of polymers from a small group of D.
Proteins are made from only 20 different E. acids

Answer 9

A. macromolecules B. polymers C.Monomers D monomers E. amino

Question 10

DNA is built from just four kinds of A.
The monomers used to make polymers are universal but polymers differ from B. Monomers are linked together to form polymers through C., which remove a water molecule.
Polymers are broken apart by D., the addition of water. All biological reactions of this sort are mediated by E., which speed up chemical reactions in cells. The names for most enzymes end on F..

Answer 10

A. nucleotides B. species to species C. dehydration reactions D. hydrolysis E. enzymes F.–ase

Question 11

A. range from small sugar molecules (B.) to large C. Sugar monomers are D., such as glucose and fructose
These can be hooked together to form the polysaccharides. The carbon skeletons of monosaccharides vary in length
Glucose and fructose are E. carbons long. Others have three to seven carbon atoms.
Monosaccharides are the F. for cellular work
Monosaccharides are also used as raw materials to G. other organic molecules

Answer 11

A. Carbohydrates B. monomers C. polysaccharides D. monosaccharides E. six F. main fuels G. manufacture

Question 12

Two monosaccharides (monomers) can bond to form a disaccharide in a A. reaction. Another example is a glucose monomer bonding to a fructose monomer to form B., a common disaccharide.

Answer 12

dehydration sucrose

Question 13

When you drink a soda, you are probably consuming a sweetener called A. (HFCS).Because fructose is sweeter than glucose, glucose atoms produced from the breakdown of starch are rearranged to make the glucose isomer, B.. Fructose is used to sweeten sodas because it is cheaper, tastier and mixes easier.
So, if you over consume sweeteners as well as fat and do not exercise, you may experience C.

Answer 13

A. high-fructose corn syrup B. fructose C. weight gain

Question 14

A. are polymers of monosaccharides linked by B..
They can function in the cell as a C.
D. is a storage polysaccharide composed of glucose monomers and found in E..
F. is a storage polysaccharide composed of glucose, which is hydrolyzed by animals when glucose is needed. G. is a polymer of glucose that forms plant cell walls. H. is a polysaccharide used by insects and crustaceans to build an I..
Polysaccharides are hydrophilic (water-loving)
Cotton fibers, such as those in bath towels, are J.

Answer 14

A.Polysaccharides B. dehydration synthesis C. storage molecule or as a structural compound. D. Starch E. plants F. Glycogen G.Cellulose H.Chitin I. exoskeleton J.water absorbent

Question 15

A. are water insoluble (hydrophobic, or water fearing) compounds that are important in energy storage.They contain B. energy as a polysaccharide
Fats are lipids made from C. and fatty acids.
Fatty acids link to glycerol by a D.
A fat contains E. glycerol linked to F. fatty acids. Fats are often called G. because of their structure.

Answer 15

A. Lipids B. twice as much C.glycerol D. dehydration reaction E. one F. Three G. triglycerides

Question 16

Some fatty acids contain double bonds
This causes kinks or bends in the A. b/c the max number of hydrogen atoms cannot bond to the carbons at the B. . These compounds are called C. because they have fewer than the maximum number of hydrogens.
Can’t pack together and solidify at room temperature.Fats with the maximum number of hydrogens are called D.
Can pack together and solidify at room temperature.

Answer 16

A. carbon chain B.double bond C.Unsaturated Fats D.saturated fats

Question 17

Phospholipids are structurally A. to fats and are an important component of all cells
Only B. fatty acids are attached to the glycerol. A negatively charged phosphate is attached to the C. carbonPhospholipids are a major part of D. , in which they cluster into a bilayer of phospholipids.
The hydrophilic heads are in contact with the water of the environment and the E. part of the cellThe hydrophobic tails band in the center of the F.

Answer 17

A.Similar B. 2 C.3rd D.cell membranes E. internal F. bilayer

Question 18

A. are lipids composed of fused ring structures
Cholesterol is an example of a steroid that plays a significant role in the structure of the cell membrane. In addition, cholesterol is the compound from which we synthesize sex B.
C.are synthetic variants of testosterone that can cause a buildup of muscle and bone mass. They can be sold as prescription drugs and used to treat D.They may also be abused with serious consequences, such as liver damage that can lead to cancer, violent mood swings, depression and shrunken testicles.

Answer 18

A. Steroids B. Hormones C. Anabolic steroids D. certain diseases

Question 19

A protein is a A. built from various combinations of B. amino acid monomers. Amino acids, the C. of proteins, have an amino group and a carboxyl group. Both of these are covalently bonded to a central D.
Also bonded to the central carbon is a E. and some other chemical group symbolized by F.

Answer 19

A. polymer B. 20 C. building blocks D.carbon atom E. hydrogen atom F. R

Question 20

Amino acids are classified as hydrophobic or hydrophilic. Some amino acids have a nonpolar R group and are A.
Others have a polar R group and are B, which means they easily dissolve in aqueous solutions. Amino acid monomers are linked together in enzyme-mediated dehydration reactions. This links the carboxyl group of one amino acid to the amino group of the next amino acid. The covalent linkage resulting is called a C.Each resulting polypeptide has a unique sequence of amino acids.

Answer 20

A.hydrophobic B. Hydrophilic C. peptide bond

Question 21

A A. contains hundreds or thousands of amino acids linked by peptide bonds. The amino acid sequence causes the polypeptide to assume a particular shape
The shape of a protein determines its B .Proteins have unique structures that are directly related to their functions.
Nearly every dynamic function in your body depends on C.. D, proteins that serve as metabolic catalysts, regulate the chemical reactions within cells

Answer 21

A.polypeptide chain B. specific function C. proteins D. Enzymes

Question 22

A.provide associations between body parts and are in connective tissues like hair, tendons and ligaments. B. are found within muscle.
C. include antibodies of the immune system. D. are best exemplified by the hormones and other chemical messengers.
E. serve as antenna for outside signals. F. carry oxygen and other essential molecules throughout the body.
G. serve as a source of amino acids for developing embryos.

Answer 22

A. Structural proteins B. Contractile proteins C. Defensive proteins D. Signal proteins E. Receptor proteins F. Transport proteins G. Storage proteins

Question 23

If for some reason a protein’s shape is altered, it can no longer A.. B. will cause polypeptide chains to unravel and lose their shape and, thus, their function
Proteins can be denatured by changes in salt concentration, pH and temperature.

Answer 23

A.function B. Denaturation

Question 24

A protein can have four levels of structure
A. The primary structure of a protein is its unique amino acid sequence
The correct amino acid sequence is determined by the cell’s genetic information. The slightest change in this sequence affects the protein’s ability to function.Protein secondary structure results from coiling or folding of the polypeptide
Coiling results in a helical structure called an B.
Folding may lead to a structure called a pleated sheet
Coiling and folding result from C.between certain areas of the polypeptide chain

Answer 24

A. Primary structure
Secondary structure
Tertiary structure
Quaternary structure
B. alpha helix
C. hydrogen bonding

Question 25

The overall three-dimensional shape of a protein is called its A..Tertiary structure generally results from interactions between the B.of the various amino acids
C. are covalent bonds that further strengthen the protein’s shape. Two or more D. (subunits) associate providing E..Collagen is an example of a protein with quaternary structure
Its triple helix gives great strength to connective tissue, bone, tendons, and ligaments.

Answer 25

A.tertiary structure B. R groups C.Disulfide bridges D. polypeptide chains E. quaternary structure

Question 26

A. (deoxyribonucleic acid) is the genetic material that humans and other organisms inherit from their parents. These genetic instructions (genes) program all of a cell’s activities by directing the synthesis of B.
A gene directs the synthesis of C. (ribonucleic acid) molecules.
RNA molecules move out of the nucleus and interact with the protein building machinery of the cell.

Answer 26

A. DNA B.proteins C. RNA

Question 27

DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are composed of monomers called A.. Nucleotides have three parts
A five-carbon sugar called B.in RNA and C. in DNA
A phosphate group
A nitrogenous base
DNA nitrogenous bases are adenine (A), thymine (T), cytosine (C), and guanine (G)
RNA also has A, C, and G, but instead of T, it has uracil (U).

Answer 27

A.nucleotides B.ribose C.deoxyribose

Question 28

A , A.a polynucleotide, forms from the nucleotide monomers when the phosphate of one nucleotide bonds to the sugar of the next nucleotide. The result is a repeating sugar-phosphate B. with protruding nitrogenous bases.
Two polynucleotide strands wrap around each other to form a C. The two strands are associated because particular bases always hydrogen bond to one another
A pairs with T, and C pairs with G, producing base pairs
RNA is usually a single D..

Answer 28

A. nucleic acid B. polymer backbone C. DNA double helix D. polynucleotide strand

Question 29

Most DNA molecules consist of millions of base pairs and, consequently, many genes. These genes, many of which are unique to the species, determine the structure of proteins and, thus, life’s structures and functions.Mutations are alterations in bases or the sequence of bases in DNA
A. is the result of mutations. In many people, the gene that dictates lactose utilization (lactase production) is turned off in adulthood
Apparently, mutations occurred over time that prevented the gene from turning off
This is an excellent example of human evolution

Answer 29

A. Lactose tolerance