Chem, Ch 11 Nucleic Acids And Protein Synthesis, Exam 3

Front 1

An individual section of a DNA strand carrying the information needed for the synthesis of a specific protein. The basic unit of heredity.

Back 1

gene

Front 2

A subcellular particle that serves as the site of protein synthesis.

Back 2

ribosome

Front 3

The conversion of the code carried by mRNA into an amino acid sequence of a protein.

Back 3

translation

Front 4

A segment of DNA that carries no codes for amino acids.

Back 4

intron

Front 5

Circular, double-stranded DNA found in the cytoplasm of bacterial cells.

Back 5

plasmid

Front 6

The transfer of genetic information from a DNA molecule to a molecule of mRNA.

Back 6

transcription

Front 7

Movement of a ribosome along an mRNA during protein synthesis.

Back 7

translocation

Front 8

During the synthesis of RNA, an adenine nucleotide on DNA will be base-paired with

Back 8

uracil

Front 9

Which of the following is NOT a component of the site of protein synthesis?

a.mRNA

b.tRNA

c.rRNA

d.hnRNA

e.more than one choice is correct

Back 9

hnRNA

Front 10

The site on a tRNA molecule that bonds with an mRNA molecule is the

Back 10

anticodon

Front 11

Okazaki fragments are linked together by a

Back 11

ligase

Front 12

One strand of DNA has the base sequence AATGCT (written in the 5' to 3' direction). What is the base sequence for the complementary DNA strand in the 5' to 3' direction?

a.AGCAUU

b.CCGTAG

c.GATGCC

d.TTACGA

e.AGCATT

Back 12

AGCATT

Front 13

During replication, nucleotides are joined together under the influence of .---blank..

Back 13

DNA polymerase

Front 14

How many nucleotide bases on an mRNA strand are needed to code for a peptide that is 8 amino acids in length?

Back 14

24

Front 15

The central dogma of molecular biology involves

Back 15

DNA → RNA → protein

Front 16

mRNA in eukaryotic cells contains information from which DNA segments when the transcription is complete?

Back 16

exons only

Front 17

The fact that most amino acids are represented by more than one mRNA codon is referred to as

Back 17

degeneracy

Front 18

An RNA chain being synthesized grows in the ________ direction.

Back 18

5' → 3'

Front 19

What stage of protein synthesis is occurring when the large and small ribosomal units move one codon at a time along the mRNA strand?

Back 19

chain elongation

Front 20

In genetic engineering, desirable DNA can be cleaved at specific base sequences by

Back 20

restriction enzymes

Front 21

Nucleic acids are classified into two categories: .---blank., found mainly in the cytoplasm of living cells, and .---blank., found primarily in the nuclei of cells.

Back 21

ribonucleic acid (RNA)

deoxyribonucleic acid (DNA)

Front 22

.---blank.is the nucleic acid found primarily in the cytoplasm of living cells.

Back 22

ribonucleic acid (RNA)

Front 23

Both DNA and RNA are polymers, consisting of long, linear molecules. The repeating structural units, or monomers, of the nucleic acids are called .---blank..

Back 23

nucleotides

Front 24

The repeating units, or monomers, found in DNA and RNA are called .---blank..

Back 24

nucleotides

Front 25

Nucleotides are composed of three components: a .---blank., a sugar, and a phosphate

Back 25

heterocyclic base

Front 26

Three components: a heterocylic base, a .---blank., and a phosphate comprise all nucleotides.

Back 26

sugar

Front 27

.---blank. commonly found in nucleic acids can be classified as either a pyrimidine or a purine.

Back 27

Heterocyclic bases

Front 28

The heterocyclic base portions of nucleic acids are either .---blank. or purines.

Back 28

pyrimidines or purine

Front 29

The three .---blank. bases are uracil, thymine, and cytosine, usually abbreviated U, T, and C. Adenine (A) and guanine (G) are the two purine bases

Back 29

pyrimidine

Front 30

A and G are .---blank. bases.

Back 30

purine

Front 31

Adenine, guanine, and cytosine are found in both DNA and RNA, but .---blank.is ordinarily found only in RNA, and .---blank.only in DNA.

Back 31

uracil

thymine

Front 32

The base .---blank. is a pyrimidine base found only in ribonucleic acids.

Back 32

uracil

Front 33

The sugar component of RNA is ribose, as the name ribonucleic acid implies. In deoxyribonucleic acid (DNA), the sugar is deoxyribose. The deoxy- prefix denotes the absence of a .---blank. which is present in ribose.

Back 33

hydroxy group

Front 34

The sugar component of DNA is called .---blank..

Back 34

deoxyribose

Front 35

The nucleotides are joined together in nucleic acids by .---blank. that connect the 5' carbon of one nucleotide to the 3' carbon of the next. These linkages are referred to as phosphodiester bonds

Back 35

phosphate groups

Front 36

Nucleotides are joined together by .---blank. bonds.

Back 36

phosphodiester

Front 37

The sugar-phosphate chain is referred to as the .---blank. backbone

Back 37

nucleic acid

Front 38

The nucleic acid backbone consists of the .---blank. chain.

Back 38

sugar-phosphate

Front 39

Watson and Crick, from various experimental data, theorized that a secondary structure of DNA consists of two strands entwined around each other in a .---blank.

Back 39

double helix

Front 40

The secondary structure of DNA contains two strands of DNA that form a .---blank. helix.

Back 40

double

Front 41

The two intertwined polynucleotide chains of the DNA double helix run in opposite (antiparallel) directions. Thus, each end of the double helix contains the 5' end of one chain and the .---blank. end of the other.

Back 41

3'

Front 42

Two polynucleotide chains running in opposite directions are said to be .---blank. .

Back 42

antiparallel

Front 43

The DNA structure is stabilized by hydrogen bonding between the bases that extend inward from the .---blank. backbone.

Back 43

sugar-phosphate

Front 44

.---blank. interactions between atoms in the base portion of nucleotides provide the stabilizing force to the double helix.

Back 44

hydrogen bonding

Front 45

Complimentary DNA strands are two strands of DNA in a double helix with matching bases forming .---blank. . The most common complimentary base pairs in double-helical DNA are the thymine-adenine pair and the guanine-cytosine base pair. In either case, a purine base hydrogen bonds with a pyrimidine base. In the case of the A-T interaction, 2 hydrogen bonds are involved. For the C-G interaction 3 hydrogen bonds are involved.

Back 45

hydrogen bonds

Front 46

The two most common base pairs in DNA double helixes are the thymine- adenine pair and the guanine-_____________ base pair.

Back 46

cytosine

Front 47

Give two reasons why adenine cannot hydrogen bond with gaunine in a DNA double helix.

Back 47

1) Both adenine and guanine are purine bases - a purine must interact with a pyrimidine.

2) Adenine only has 2 places to hydrogen bond; whereas, guanine has 3 places to hydrogen bond.

Front 48

One strand of a DNA molecule has the base sequence of .---blank. (written in the 5' to 3' direction).

Back 48

CCATTG

Front 49

What is the base sequence for the complementary strand in the 5' to 3' direction?

Back 49

CAATGG

Front 50

A human cell normally contains 46 structural units called .---blank.

Back 50

chromosomes

Front 51

A human cell contains .---blank. chromosomes.

Back 51

46

Front 52

Each chromosome contains one molecule of DNA coiled tightly about a group of small, basic proteins called .---blank. .

Back 52

histones

Front 53

.---blank. are the small basic proteins that form the core around which DNA is coiled in chromosomes.

Back 53

histones

Front 54

Individual sections of DNA molecules make up .---blank. , the fundamental units of heredity. Each gene directs the synthesis of a specific protein or, in some cases, a series of proteins.

Back 54

genes

Front 55

.---blank. are sections of DNA that are the fundamental units of heredity.

Back 55

genes

Front 56

A bacterial cell may contain .---blank. genes, whereas a human cell contains approximately 30,000 genes.

Back 56

1000

Front 57

A human cell contains an estimated .---blank. genes.

Back 57

30,000

Front 58

The process by which an exact copy of DNA is produced is called .---blank. .

Back 58

replication

Front 59

DNA molecules are copied by a process called .---blank. .

Back 59

replication

Front 60

.---blank. replication is a replication process that produces DNA molecules containing one strand from the parent and a new strand that is complementary to the strand from the parent

Back 60

Semiconservative

Front 61

The type of replication process that produces a DNA copy with a new strand and one from the parent is known as .---blank. replication.

Back 61

Semiconservative

Front 62

Step one in the replication process is the unwinding of the double helix catalyzed by the enzyme .---blank. .

Back 62

helicase

Front 63

.---blank. is the enzyme that catalyzes the unwinding of the double helix in the first step of DNA replication.

Back 63

helicase

Front 64

The point at which the unwinding of the double helix takes place is called the .---blank.

Back 64

replication fork

Front 65

Helix unwinding is initiated at the .---blank. .

Back 65

replication fork

Front 66

Step two of DNA replication involves synthesis of DNA segments. New daughter strands form as nucleotides, complementary to those on the exposed strands, are linked together under the influence of the enzyme .---blank.

Back 66

DNA polymerase

Front 67

The enzyme .---blank. is responsible for the synthesis of DNA.

Back 67

DNA polymerase

Front 68

DNA polymerase synthesizes the daughter chains in the .---blank. to the 3' direction.

Back 68

5’

Front 69

The direction of growth of the DNA daughter chain is from the .---blank. end.

Back 69

5’

Front 70

.---blank. fragments are DNA fragments produced during replication as a result of strand growth in a direction away from the replication fork.

Back 70

Okazaki

Front 71

Because growth of one strand proceeds away from the replication fork, .---blank. fragments are formed

Back 71

Okazaki

Front 72

Step 3 of DNA replication involves closing the nicks between the .---blank. fragments on one strand of the newly synthesized DNA. The other daughter strand contains a continuous chain of nucleotides and does not require this process.

Back 72

Okazaki

Front 73

The final step of DNA replication involves closing nicks between .---blank. fragments on one strand.

Back 73

Okazaki

Front 74

An enzyme called .---blank. is responsible for catalyzing the joining of the Okazaki fragments.

Back 74

DNA ligase

Front 75

Okazaki fragments are joined by the enzyme .---blank. .

Back 75

DNA ligase

Front 76

Through detailed understanding of DNA replication, a revolutionary laboratory technique called the polymerase chain reaction (PCR) was born. .---blank. mimics the natural DNA replication process in a controlled laboratory environment.

Back 76

PCR

Front 77

The .---blank. technique is a process through which scientists duplicate natural DNA replication outside living cells.

Back 77

PCR

Front 78

The primary structure of RNA differs from that of DNA in two ways. As we learned in Section 11.1, the sugar unit in RNA is ribose rather than deoxyribose. The other difference is that RNA contains the base .---blank. (U) instead of thymine (T).

Back 78

uracil

Front 79

The base .---blank. is found in RNA in place of thymine.

Back 79

uracil

Front 80

The secondary structure of RNA is also different from that of DNA. RNA molecules are .---blank. -stranded, except in some viruses.

Back 80

single

Front 81

RNA molecules exist primarily as .---blank. strands.

Back 81

single

Front 82

Cells contain three types of RNA: messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). Each of these kinds of RNA performs an important function in .---blank. synthesis.

Back 82

proteins

Front 83

RNA molecules are involved in the synthesis of .---blank. .

Back 83

proteins

Front 84

.---blank. (mRNA) functions as a carrier of genetic information from the DNA of the cell nucleus directly to the cytoplasm.

Back 84

messenger RNA

Front 85

Genetic information is carried from the cell nucleus to the cytoplasm via .---blank. .

Back 85

messenger RNA

Front 86

Molecules of mRNA have a short .---blank. , usually less than 1 hour.

Back 86

lifetime

Front 87

In general terms, the turnover rates for mRNA are .---blank. .

Back 87

rapid

Front 88

A .---blank. is a subcellular particle that serves as the site of protein synthesis in all organisms.

Back 88

ribosome

Front 89

.---blank. function as the site of protein synthesis.

Back 89

ribosomes

Front 90

.---blank. RNA (rRNA) constitutes 80-85% of the total RNA of the cell. It is located in the cytoplasm in organelles called ribosomes.

Back 90

ribosomal

Front 91

.---blank. RNA makes up the majority of a cell's RNA.

Back 91

ribosomal

Front 92

.---blank. molecules deliver amino acids, the building blocks of proteins, to the site of protein synthesis.

Back 92

transfer RNA

Front 93

Amino acids are delivered to ribosomes via .---blank. .

Back 93

transfer RNA

Front 94

The .---blank. molecules are the smallest of all the nucleic acids, containing 73-93 nucleotides per chain.

Back 94

tRNA

Front 95

The smallest of the nucleic acid molecules are those of .---blank. .

Back 95

tRNA

Front 96

Two regions of tRNA molecules have important functions during protein synthesis. The .---blank. enables the tRNA to bind to mRNA during protein synthesis

Back 96

anticodon

Front 97

The .---blank. portion of tRNA molecule is the binding site for mRNA during protein synthesis.

Back 97

anticodon

Front 98

The second important site of tRNA is the .---blank. end of the molecule, which binds to an amino acid and transports it to the site of protein synthesis.

Back 98

3’

Front 99

The .---blank. end of the tRNA molecule is the binding site for the amino acid it carries.

Back 99

3’

Front 100

The central dogma of molecular biology is the well-established process by which genetic information stored in DNA molecules is expressed in the structure of synthesized .---blank. .

Back 100

protein

Front 101

The process by which genetic information is expressed in .---blank. structure constitutes the central dogma of molecular biology.

Back 101

protein

Front 102

Genetic information contained in DNA molecules is transferred to .---blank. molecules, followed by expression of this information in the structure of synthesized proteins.

Back 102

RNA

Front 103

.---blank. provide the link between genetic information stored in DNA and the structure of proteins.

Back 103

RNA

Front 104

Before proteins can be synthesized, the stored information must be carried out of the nucleus. This is accomplished by .---blank. , or transferring the necessary information from the DNA molecule onto a molecule of messenger RNA

Back 104

transcription

Front 105

.---blank. refers to the transfer of genetic information from DNA to mRNAs.

Back 105

transcription

Front 106

The mRNA serves as a template on which amino acids are assembled in the proper sequence necessary to produce the specified protein. This process, called .---blank. , takes place when the code or message carried by mRNA is converted into an amino acid sequence.

Back 106

translation

Front 107

.---blank. refers to the synthesis of a protein according to the code on the corresponding mRNA molecule.

Back 107

translation

Front 108

An enzyme called .---blank. catalyzes the synthesis of RNA. RNA polymerase reads the DNA from the 3' end of the DNA segment to the 5' end; however, it synthesizes RNA from the 5' end to the 3', similar to DNA replication.

Back 108

RNA polymerase

Front 109

The synthesis of RNA is catalyzed by .---blank. .

Back 109

RNA polymerase

Front 110

RNA transcription occurs in the .---blank. to .---blank. direction, while the reading of the DNA occurs in the .---blank. to .---blank. direction.

Back 110

5' to 3'

3' to 5'

Front 111

Genes of eukaryotic cells are segments of DNA that are "interrupted" by segments that do not code for amino acids. These DNA segments that carry no amino acid code are called .---blank. , and the coded DNA segments are called exons.

Back 111

introns

Front 112

Segments of DNA within coding DNA regions that do not code for amino acids are called .---blank. .

Back 112

introns

Front 113

When transcription occurs in the nuclei of eukaryotic cells, both introns and exons are transcribed. This produces what is called .---blank. nuclear RNA or hnRNA

Back 113

heterogeneous

Front 114

The RNA produced in the nuclei of eukaryotic cells containing RNA transcribed from both introns and exons is called .---blank. nuclear RNA.

Back 114

heterogeneous

Front 115

The long hnRNA molecule undergoes a series of enzyme-catalyzed reactions that cut and splice the hnRNA to produce .---blank. . Once the introns have been removed and mRNA has been made from the hnRNA, it can leave the nucleus to provide directions for protein synthesis in the cytoplasm.

Back 115

mRNA

Front 116

In order to form .---blank. from hnRNA, the noncoding regions must first be cut and then the coding regions joined together.

Back 116

mRNA

Front 117

When a protein is synthesized, it will only contain information from the (introns/exons) of the DNA sequence.

Back 117

exons

Front 118

Nature uses three-letter code words to store and express genetic information. Each sequence of three nucleotide bases that represents code words on mRNA molecules is called a .---blank.

Back 118

codons

Front 119

The three letter codes that store and express genetic information are called .---blank. .

Back 119

codons

Front 120

A three base code has 43 or .---blank. possible combinations.

Back 120

64

Front 121

There are .---blank. possible codons.

Back 121

64

Front 122

One important characteristic of the genetic code is that it applies to every organism (see Table 11.3). The code is almost .---blank. from species to species.

Back 122

universal

Front 123

The genetic code is almost .---blank. , differing only rarely from species to species.

Back 123

universal

Front 124

A second feature of the genetic code is that most of the amino acids are represented by more than one codon, a characteristic known as degeneracy. .---blank. helps remove the effects of any mutations caused by changes in base pairs by increasing the chances that the correct amino acid will still be coded for.

Back 124

Degeneracy

Front 125

a) The genetic code is said to be .---blank. when an amino acid is represented by more than one codon.

Back 125

degenerate

Front 126

The codons that signal for phenylalanine are UUC and UUU. If the codon were UUU and the third nucleotide was changed (mutated), what are the chances that phenyl-alanine would still be coded for?

Back 126

UUU could be mutated to UUC, UUG, and UUA. UUC still codes for phenylalanine, so there would be a 1/3 or 33% chance that phenylalanine would still be coded for.

Front 127

Only 61 of the possible 64 base triplets represent amino acids. The remaining three (UAA, UAG, UGA) are signals for .---blank. .

Back 127

chain termination

Front 128

Codons that do not code for amino acids are signals for .---blank. .

Back 128

chain termination

Front 129

There is only one initiation (start) codon, and it is AUG, the codon for the amino acid .---blank. .

Back 129

methionine

Front 130

AUG, the chain initiation signal, codes for the amino acid .---blank. .

Back 130

methionine

Front 131

There are three major stages in protein synthesis: initiation of the polypeptide chain, .---blank. of the chain, and termination of the completed polypeptide chain

Back 131

elongation

Front 132

The three steps of protein synthesis are initiation, .---blank. and termination.

Back 132

elongation

Front 133

The initiation process begins when mRNA is aligned on the surface of a small ribosomal subunit in such a way that the initiating codon, AUG, occupies a specific site on the ribosome called the .---blank. site (peptidyl site).

Back 133

P

Front 134

The initiating codon of the mRNA must occupy the .---blank. site of the ribosome for the initiation process to begin.

Back 134

P

Front 135

A tRNA molecule with its attached f-Met binds to the codon through hydrogen bonds. The resulting complex binds to the large ribosomal subunit to form a unit called an .---blank. .---

Back 135

initiation complex

Front 136

Upon binding of the large ribosomal subunit to the mRNA, followed by binding of the small ribosomal subunit and the f-Met tRNA molecule, the .---blank. complex is complete, enabling the next step of protein synthesis to commence.

Back 136

initiation

Front 137

A second site, called the .---blank. site (aminoacyl site), is located on the mRNA-ribosome complex next to the P-site. The A site is occupied by an incoming tRNA carrying the next amino acid. Each codon that codes for an amino acid on the mRNA consists of 3 nucleotide bases.

Back 137

A

Front 138

a) The binding site for incoming tRNA molecules adjacent to the P site is called the .---blank. .

Back 138

A site

Front 139

b) A polypeptide is 6 amino acids long. How many nucleotides on an mRNA strand are necessary to code for this polypeptide?

Back 139

6 x 3 = 18 nucleotides

Front 140

After a tRNA molecule binds to the A-site, the whole ribosome moves one codon along the mRNA toward the 3' end. This movement of the ribosome along the mRNA is called .---blank. , during which the A site becomes available to the next tRNA with the proper anticodon

Back 140

translocation

Front 141

.---blank. is the process by which the ribosome moves along the mRNA molecule.

Back 141

translocation

Front 142

The chain elongation process and polypeptide synthesis continue until the ribosome complex reaches a .---blank. (UAA, UAG, UGA) on the mRNA.

Back 142

stop codon

Front 143

The presence of a .---blank. codon results in termination of polypeptide synthesis.

Back 143

stop

Front 144

Several .---blank. can move along a single strand of mRNA one after another. Complexes of several ribosomes and mRNA are called polyribosomes or polysomes

Back 144

ribosomes

Front 145

Polyribosomes contain several .---blank. on a single mRNA strand.

Back 145

ribosomes

Front 146

Any change resulting in an incorrect sequence of bases on DNA is called a .---blank. .

Back 146

Mutation

Front 147

A .---blank. is a change resulting in an incorrect sequence of DNA bases.

Back 147

mutation

Front 148

Some mutations occur naturally during DNA replication; others can be induced by environmental factors such as ionizing radiation (X rays, ultraviolet light, gamma rays, etc.). A large number of chemicals (e.g. nitrous acid and dimethyl sulfate) can also induce mutations by reacting with DNA. Such chemicals are called .---blank. .

Back 148

mutagens

Front 149

DNA mutations can occur naturally during DNA replication, or by environmental factors such as .---blank. radiation, or as the result of exposure to chemicals called .---blank. .

Back 149

ionizing, mutagens

Front 150

Remarkable technology is available that allows segments of DNA from one organism to be introduced into the genetic material of another organism. The resulting new DNA (containing the foreign segment) is referred to as .---blank. .

Back 150

recombinant DNA

Front 151

DNA of an organism that contains genetic material from another organism is called .---blank. DNA.

Back 151

recombinant

Front 152

The discovery of restriction enzymes in the 1960s and 1970s made genetic engineering possible. .---blank. enzymes are protective enzymes found in a wide variety of bacteria catalyzing the cleaving of foreign DNA at specific sequences.

Back 152

restricition

Front 153

Enzymes that catalyze the cleavage of foreign DNA in specific sequences are called .---blank. enzymes.

Back 153

restricition

Front 154

Another set of enzymes important in genetic engineering, called .---blank. , has been known since 1967. These enzymes normally function to connect DNA fragments during replication, and they are used in genetic engineering to put together pieces of DNA produced by restriction enzymes.

Back 154

DNA ligase

Front 155

In genetic engineering, pieces that are cleaved by restriction enzymes are connected through the use of .---blank. .

Back 155

DNA ligase

Front 156

The introduction of a new DNA segment (gene) into a bacterial cell requires the assistance of a DNA carrier called a .---blank. .

Back 156

vectors

Front 157

.---blank. are DNA carriers used in genetic engineering to introduce foreign DNA into the desired cell.

Back 157

vectors

Front 158

Vectors are often circular units of double-stranded DNA called .---blank. , which are isolated from the cytoplasm of bacterial cells.

Back 158

plasmids

Front 159

Circular units of DNA often used as vectors are called .---blank. .

Back 159

plasmids