Deck 3: Lifes Components: Biological Molecules

Question 1

In many cases, carbohydrates have the following ratio of elements:

A) carbon, hydrogen, and oxygen in a ratio of 1:2:1.
B) carbon and hydrogen in a ratio of 1:2.
C) carbon, hydrogen, and nitrogen in a ratio of 1:2:1.
D) carbon, oxygen, and hydrogen in a ratio of 1:2:1.
E) carbon, hydrogen, and oxygen in a ratio of 2:1:2.

Answer 1

A

Question 2

A functional group added to a hydrocarbon usually makes the hydrocarbon:

A) nonpolar.
B) hydrophobic.
C) polar.
D) acidic.
E) an isomer.

Answer 2

C

Question 3

All of the following are monosaccharides except:

A) fructose.
B) cellulose.
C) glucose.
D) deoxyribose.

Answer 3

B

Question 4

Sugar is an organic molecule because it contains:

A) carbon and nitrogen.
B) carbon.
C) water.
D) carbon dioxide.
E) carbon and oxygen.

Question 5

Glycogen is a polysaccharide used for energy storage by:

A) plants.
B) animals.
C) monera.
D) fungi.

Question 6

Unique chemical groups that confer special properties to an organic molecule are called:

A) monomers.
B) amino acids.
C) functional groups.
D) lipids.

Question 7

Which of the following is true of cellulose?

A) Plants store glucose as cellulose.
B) Animals store glucose as cellulose.
C) Plants store amino acids as cellulose.
D) Plants' cell walls are made up of cellulose.

Question 8

In the following chemical reaction, which molecule is the disaccharide? glucose + fructose → sucrose + water

A) sucrose
B) glucose
C) water
D) fructose

Question 9

Glycogen is used to store ________ in the ________.

A) protein; muscle
B) protein; liver
C) nucleic acids; liver
D) glucose; spleen
E) glucose; liver

Question 10

The monomers of polysaccharides are:

A) nucleotides.
B) simple sugars.
C) amino acids.
D) fatty acids.

Question 11

Which of the following is the indigestible (at least for humans) glucose polysaccharide that is found in plants?

A) starch
B) glycogen
C) cellulose
D) chitin

Question 12

Which of the following are polysaccharides?

A) sucrose and glucose
B) fructose and deoxyribose
C) DNA and RNA
D) starch and glycogen

Question 13

What do polysaccharides, such as cellulose; nucleic acids, such as DNA; and proteins, such as keratin, have in common?

A) They are all built of chemically linked monomers.
B) They are all amino acids.
C) They are all lipids.
D) They are all carbohydrates.
E) They are all nonpolar.

Question 14

Carbon is such an important element for life because it:

A) forms strong ionic bonds.
B) can form chemical bonds with a maximum of four other atoms.
C) can hydrogen bond to many different molecules.
D) is part of the water molecule.
E) does not form isomers.

Question 15

Chitin and cellulose are examples of:

A) structural polysaccharides.
B) storage polysaccharides.
C) monosaccharides.
D) disacchrides.

Question 16

Butane and isobutane are isomers. This means they have the same:

A) arrangement of atoms but a different chemical formula.
B) number of carbon atoms but different numbers of hydrogen atoms.
C) chemical formula but a different arrangement of atoms.
D) chemical formula but can only exist as ring structures.

Question 17

Hydroxyl groups are commonly found in:

A) amino acids.
B) DNA.
C) carbohydrates.
D) fatty acids.

Question 18

In some vintage science fiction movies, space travelers find themselves on a planet orbiting a distant star in which there are curious forms of life based on silicon instead of carbon. Although the story clearly is sci-fi, there is an aura of plausibility in the choice of silicon, an atom with 14 protons, in place of carbon as this alien life-form's central atom. The reason is that silicon:

A) has four electrons in its outermost shell.
B) has one more proton than carbon, so is very similar to it.
C) is an isotope of carbon.
D) is lighter than carbon.
E) is heavier than carbon.

Question 19

Which of the following contains both a carboxyl group and an amino group?

A) carbohydrates
B) nucleotides
C) amino acids
D) lipids

Question 20

The monomers of polysaccharides are:

A) amino acids.
B) nucleotides.
C) steroids.
D) lipids.
E) sugars.

Question 21

All of the following are functions of proteins except:

A) hormone activity.
B) enzyme activity.
C) serving as structural building materials.
D) serving as transport molecules.
E) storing genetic information.

Question 22

Many features of a protein change when it is moved into an environment with a different pH. Which of the following features would stay the same?

A) function of the protein
B) shape of the protein
C) binding properties of the protein
D) amino acid sequence of the protein
E) tertiary structure of the protein

Question 23

Saturated fats are usually found in:

A) coconut oil.
B) canola oil.
C) safflower oil.
D) a beef steak.
E) both coconut oil and a beef steak.

Question 24

Every protein has a unique shape and function because:

A) each protein has a unique sequence of nucleotides.
B) each protein has a unique sequence of amino acids.
C) the bonds between the amino acids vary from protein to protein.
D) the number of nitrogen atoms in each amino acid differs.

Question 25

Which of the following lipids is the primary component in cell membranes?

A) triglycerides
B) steroids
C) phospholipids
D) glycerol

Question 26

Which of the following is true of steroids?

A) Steroids exist naturally in humans as hormones.
B) Some amino acids are steroids.
C) If people inject male steroid hormones, they can build muscle mass with no side effects.
D) Steroids contain a central, single-ring carbon structure.
E) Steroids are polymers.

Question 27

The difference between one amino acid and another is the:

A) number of amino and carboxyl groups each contains.
B) number of R groups each contains.
C) type of R group each contains.
D) way their amino groups bond with carboxyl groups.
E) difference in the chemical properties of their amino and carboxyl groups.

Question 28

Which of the following is a polymer?

A) fat
B) steroid
C) nucleic acid
D) wax

Question 29

Butter, which is made from milk fat, tends to be harder at room temperature than most margarines. If you wanted to make a butter that is softer at room temperature, you should consider:

A) making the fatty acid chains longer.
B) making fatty acid chains with fewer kinks.
C) creating more double bonds in the fatty acid chains.
D) saturating the fatty acid chains.
E) adding more than three fatty acid chains to the triglycerides.

Question 30

You notice that water is running off the feathers of a bird in the rain. The reason is probably that the bird has coated the feathers with ________, which keeps the water out of them.

A) proteins
B) polysaccharides
C) lipids
D) nucleic acids

Question 31

Proteins that are composed of more than one polypeptide chain are said to have ________ structure.

A) secondary
B) tertiary
C) primary
D) quaternary

Question 32

What is a triglyceride?

A) a lipid made of one glycerol and two fatty acids
B) a lipid made of two glycerols, a fatty acid, and a phosphate group
C) a lipid made of one glycerol and three fatty acids
D) a carbohydrate made of three sugars
E) a polypeptide made of three amino acids

Question 33

The hydrogenation of vegetable oil results in:

A) an increase in the number of double bonds between the carbon atoms.
B) the oil becoming more liquid at room temperature.
C) a decrease in the number of double bonds between the carbon atoms.
D) the conversion of monounsaturated fatty acids into polyunsaturated fatty acids.
E) a decrease in the number of hydrogen atoms in the oil molecule.

Question 34

Unsaturated fatty acids:

A) have one or more double bonds between the carbons.
B) are usually found in animal fats.
C) have long been linked with heart disease.
D) contain the maximum number of hydrogen atoms possible.

Question 35

If you removed the cuticle from the skin of an apple, the:

A) apple would absorb moisture and get soggy.
B) apple would lose water and dehydrate.
C) seeds of the apple would die.
D) apple would be inedible.

Question 36

Which of the following is an example of a lipid?

A) cholesterol
B) cellulose
C) keratin
D) chitin

Question 37

A triglyceride contains ________ fatty acid chains, whereas a phospholipid contains ________ fatty acid chains.

A) two; three
B) four; two
C) two; four
D) three; two

Question 38

Alpha helices and beta pleated sheets are examples of:

A) primary structure.
B) secondary structure.
C) tertiary structure.
D) quaternary structure.

Question 39

An example of an important biological molecule that may contain the -NH₂ group is:

A) a triglyceride.
B) a starch.
C) a glucose molecule.
D) an enzyme.
E) steroids.

Question 40

What do wax and testosterone have in common?

A) They are both hormones.
B) They are both proteins.
C) They are both steroids.
D) They are both lipids.

Question 41

Match the following.

A) DNA
B) lipoproteins
C) glycoproteins
D) polysaccharide
E) structural proteins
A carbohydrate polymer

Question 42

The two chains of nucleotides in a DNA molecule are held together by:

A) covalent bonds.
B) ionic bonds.
C) hydrogen bonds.
D) peptide bonds.
E) hydrophobic interactions.

Question 43

Hydroxyl groups are functional groups found on amino acids.

Question 44

Cholesterol is used to make other steroids in the body.

Question 45

Amino acids are monomers used to build:

A) nucleic acids.
B) triglycerides.
C) polysaccharides.
D) proteins.

Question 46

Lipids with carbon-carbon double bonds tend to be more solid at room temperature.

Question 47

Before DNA was established as the genetic material, proteins were considered the most likely molecules to serve this role. In part this belief was based on the fact that there are 20 building blocks (20 different kinds of amino acids) for proteins versus 4 building blocks (4 different nucleotides) for DNA. If proteins stored a code, there would be a far greater number of code words possible for a protein of a given number of amino acids than for a DNA molecule of the same number of nucleotides. For example, there are 16 different sequences (4²) possible for a DNA two nucleotides long and 400 (20²) different sequences possible for a protein two amino acids long. For a sequence three nucleotides or three amino acids in length, the number of distinct DNA sequences is ________, and the number of distinct protein sequences is ________.

A) 64; 8,000
B) 800; 8,000
C) 30; 800
D) 64; 800
E) 20; 420

Question 48

Nucleotides are the building blocks for:

A) disaccharides.
B) ATP, DNA, and RNA.
C) proteins.
D) lipids.
E) steroids.

Question 49

Your muscles contract using contractile proteins to produce movement.

Question 50

All other levels of protein structure are dictated by the primary structure.

Question 51

Water is an organic molecule.

Question 52

A nucleotide is a polymer of nucleic acids.

Question 53

All hormones are steroids.

Question 54

Both men and women make testosterone.

Question 55

Most enzymes are proteins, but not all proteins are enzymes.

Question 56

Amino acids contain both amino and carboxyl functional groups.

Question 57

The chitin that makes up the exoskeleton of insects is a polymer of amino acids.

Question 58

Which of the following is the correct order for the flow of information in the cell?

A) Proteins code for DNA, which codes for RNA.
B) RNA codes for DNA, which codes for protein.
C) DNA codes for protein, which codes for RNA.
D) DNA codes for RNA, which codes for protein.

Question 59

Wax is a lipid.

Question 60

Glycogen is the carbohydrate found in plant cell walls.

Question 61

Polypeptides differ in their ________ and ________ of amino acids.

Question 62

If you boil an egg for lunch, the egg white becomes hard, white, and opaque because the protein molecules have unfolded, causing them to stick together. This is an example of how heat ________ a protein.

Question 63

Ribosomes are made up of protein and ________.

Question 64

A series of amino acids linked in linear fashion is called a ________.

Question 65

Match the following.

A) DNA
B) lipoproteins
C) glycoproteins
D) polysaccharide
E) structural proteins
The primary information-bearing molecule of life

Question 66

________ is a branch of chemistry that studies carbon compounds.

Question 67

Mutations are changes to the information in DNA. What would happen to an enzyme's ability to function if a mutation changed the order of some of the amino acids in its polypeptide chain?

Question 68

You have a genetic defect that prevents your cells from making the amino acid tryptophan from indole and serine. Your cells might be lacking the proper information in their ________, which would direct the synthesis of the ________ that catalyzes tryptophan synthesis.

Question 69

ATP (adenosine triphosphate) is an energy-carrying, modified ________.

Question 70

Describe the structure of phospholipids, and state where they are found in cells.

Question 71

Match the following.

A) DNA
B) lipoproteins
C) glycoproteins
D) polysaccharide
E) structural proteins
Transport fats throughout the body

Question 72

Keratin is an example of a ________ protein.

Question 73

You go the store to buy some lard for cooking. You notice when you get home that the lard is solid at room temperature. What does this tell you about the fat in lard, and how does this explain it being solid at room temperature? What type of fat would not be solid at room temperature, and why?

Question 74

Name the four most important groups of biological molecules necessary for life. List one polymer and one monomer of each.

Question 75

Match the following.

A) DNA
B) lipoproteins
C) glycoproteins
D) polysaccharide
E) structural proteins
Found in hair and cartilage

Question 76

Why are proteins, polysaccharides, and nucleic acids considered polymers, but lipids are not?

Question 77

The active site of an enzyme is a product of its ________.

Question 78

The precursor from which steroid hormones are made is ________.

Question 79

Explain how a protein ends up with its final shape.

Question 80

Match the following.

A) DNA
B) lipoproteins
C) glycoproteins
D) polysaccharide
E) structural proteins
Serve as cell surface receptors