Microbiology Tortora Chapter 8 " Microbial Genetics "

Front 1

________ is the study of heredity.

Back 1

Genetics

Front 2

The genetic information in a cell is called the ___________.

Back 2

genome

Front 3

A cell's genome is organized into ______________.

Back 3

chromosomes

Front 4

A cell's genetic information is organized into ________________.

Back 4

chromosomes

Front 5

A cell's ________ is organized into chromosomes.

Back 5

genome

Front 6

________ are structures containing DNA that physically carry hereditary information.

Back 6

Chromosomes

Front 7

_________ carry genes.

Back 7

Chromosomes

Front 8

Chromosomes carry ________.

Back 8

genes

Front 9

Fill in the blanks with these two words in the proper order: chromosomes, genes.

________ carry _________.

Back 9

chromosomes carry genes

Front 10

_______ are segments of DNA

Back 10

Genes

Front 11

_______ are segments of DNA that code for functional proteins.

Back 11

Genes

Front 12

_________ are repeating units that compose the macromolecule of DNA.

Back 12

nucleotides

Front 13

What are nucleotides?

Back 13

repeating units that compose DNA

Front 14

What is the structure of a nucleotide?

Back 14

Each nucleotide consists of :

- a nitrogenous base (adenine, thymine, cytosine or guanine)
- deoxyribose ( a pentose sugar)
- phosphate group

Front 15

The ________ is an organism's genetic makeup, the information that codes for all the particular characteristics of the organism.

Back 15

genotype

Front 16

The _________ refers to the actual, expressed properties of an organism

Back 16

phenotype

Front 17

Fill in the blanks with these two words in the correct order: genotype, phenotype.

_________ is the manifestation of __________.

Back 17

phenotype is the manifestation of genotype.

Front 18

An organism's ________ is its collection of genes.

Back 18

genotype

Front 19

An organism's ________ is its entire DNA

Back 19

genotype

Front 20

An organism's _______ is its collection of proteins.

Back 20

phenotype

Front 21

The DNA within a cell exists as long strands of _______ tiwsted together in pairs to form a double-helix.

Back 21

nucleotides

Front 22

The DNA within a cell exists as long strands of nucleotides twisted together in pairs to form a ________.

Back 22

double-helix

Front 23

Each strand of DNA is made up of what?

Back 23

string of alternating sugar and phosphate groups, with a nitrogenous base attached to each sugar in the backbone.

Front 24

What is the sugar phosphate backbone?

Back 24

a string of alternating sugar and phosphate groups, with a nitrogenous base attached to each sugar of the backbone.

Front 25

Adenine always pairs with _________.

Back 25

thymine

Front 26

Thymine always pairs with ________.

Back 26

adenine

Front 27

Guanine always pairs with _________.

Back 27

cytosine

Front 28

Cytosine always pairs with ________.

Back 28

guanine

Front 29

What are the purines?

Back 29

adenine and guanine

Front 30

What are the pyrimidines?

Back 30

cytosine and thymine

Front 31

The base pairings of nucleotides are ________.

Back 31

complementary

Front 32

The two strands of DNA are _________.

Back 32

complementary

Front 33

DNA is synthesized in the _______ direction.

Back 33

5'-------->3'

Front 34

RNA synthesis continues until RNA polymerase reaches a site on the DNA called the _________.

Back 34

terminator

Front 35

What is the terminator?

Back 35

a site on the DNA that "signals" RNA polymerase to stop synthesizing RNA

Front 36

______ are the regions of DNA that are expressed

Back 36

exons

Front 37

_______ are the regions of DNA that do not encode protein.

Back 37

introns

Front 38

What are constitutive genes?

Back 38

their products are not regulated; their products are constantly produced at a fixed rate. Usually these genes are effectively turned on all the time, so they code for enzymes that the cell needs in fairly large amounts.

Front 39

What is repression?

Back 39

the regulatory mechanism that inhibits gene expression and decreases the synthesis of enzymes

Front 40

What term is best described by the following:

" The regulatory mechanism that inhibits gene expression and decreases the synthesis of enzymes is called _______. "

Back 40

repression

Front 41

Repression is mediated by regulatory proteins called ________.

Back 41

repressors

Front 42

What do repressors do?

Back 42

they block the ability of RNA polymerase to initiate transcription from the repressed genes

Front 43

What is the process that turns on the transcription of a gene/genes?

Back 43

induction

Front 44

What is induction?

Back 44

the process that turns on the transcription of a gene/genes

Front 45

A substance that acts to induce transcription of a gene is called an ________

Back 45

inducer

Front 46

what is an inducer?

Back 46

a substance that acts to induce transcription of a gene

Front 47

Enzymes synthesized in the presence of induces are ___________.

Back 47

inducible enzymes

Front 48

the combination of an operator, promeoter, and the structural genes they control is known as _______

Back 48

an operon

Front 49

What is an operon?

Back 49

the combination of an operator, promotor, and the structural genes they control.

Front 50

How are inducible operons and repressible operons different?

Back 50

In inducible operons, the structural genes are transcribed when they are turned on, or induced. In repressible operons, the structural genes are transcribed UNTIL they are turned off, or repressed.

Front 51

An example of an inducible operon is the _______ operon.

Back 51

lac

Front 52

An example of a repressible operon is the _________ operon.

Back 52

tryptophan

Front 53

Inhibition of the metabolism of alternative carbon sources by glucose is termed ___________.

Back 53

catobolite repression

Front 54

catobolite repression is also known as the ___________.

Back 54

glucose effect

Front 55

__________ is also known as the glucose effect.

Back 55

catobolite repression

Front 56

How does catabolite repression work?

Back 56

keeps making C-amp until turned off by realizing that the body has enough glucose.

Front 57

What is a bse mutation?

Back 57

a single base at one point in the DNA sequence is replaced with a different base.

Front 58

What is a missense mutation?

Back 58

If a base situation results in an amino acid substitution in the synthesized protein, it is referred to as a missense mutation

Front 59

What term is best described:

" a base situation results in an amino acid substitution in the synthesized protein "

Back 59

missense mutation

Front 60

What term is best described:

" a base substitution resulting in a stop (nonsense) codon "

Back 60

nonsense mutation

Front 61

What is a nonsense mutation?

Back 61

When a base substitution results in a stop (nonsense) codon, preventing the synthesis of a completely functional protein.

Front 62

What is a frameshift mutation?

Back 62

When one or a few of the nucleotide pairs are deleted or inserted in the DNA

Front 63

What term is best described:

" When one or a few of the nucleotide pairs are deleted or inserted in the DNA"

Back 63

frameshift mutation

Front 64

Spontaneous mutations are what?

Back 64

when mistakes occur during DNA replication in the absence of an apparent mutation-causing agents.

Front 65

What term is best described:

" when mistakes occur during DNA replication in the absence of an apparent mutation-causing agent "

Back 65

spontaneous mutation

Front 66

What are mutagens?

Back 66

agents in the environment, such as certain chemicals and radiation, that directly or indirectly bring about mutation

Front 67

What term is best described:

" agents in the environment, such as certain chemicals and radiation, that directly or indirectly bring about mutation "

Back 67

mutagens

Front 68

How do chemical mutagens work?

Back 68

convert the base adenine (A) to form in such a way that it no longer pairs with thymine (T), but with cytosine (C).

Front 69

How do ionizing radiation cause mutations?

Back 69

causes the formation of ions and free radicals that react with DNA and can break the sugar-phosphate backbone or cause base substitutions

Front 70

UV radiation causes mutations how?

Back 70

by causing bonding between adjacent thymines

Front 71

How are thymine dimers repaired?

Back 71

thymine dimers can be repaired by light-repair enzymes

Front 72

What do light-repair enzymes do?

Back 72

repair thymine dimers

Front 73

________ involves detection of mutant cells by rejection of the unmutated parent cells

Back 73

positive (direct) selection

Front 74

In lameman's terms, what does this mean:

" involves detection of mutant cells by rejection of the unmutated parent cells "

Back 74

you want the mutants!

Front 75

What term is best described:

" this process selects a cell that connot perform a certain function "

Back 75

negative (indirect) selection

Front 76

Positive selection is ________.

Back 76

direct

Front 77

Negative selection is _______.

Back 77

indirect

Front 78

Another term for direct selection is __________.

Back 78

positive selection

Front 79

another term for indirect selection is ____________.

Back 79

negative selection

Front 80

What is replica plating technique used for?

Back 80

negative selection

Front 81

_________ is a relatively inexpensive and rapid test for identifying possible chemical carcinogens.

Back 81

Ames test

Front 82

What does the Ames test identify?

Back 82

posisble chemical carcinogens

Front 83

What does the Ames test assume?

Back 83

that a mutant cell can revert to a normal cell in the presence of a mutagen, and that many mutagens are carcinogenic

Front 84

In prokaryotes, transcription occurs in the _________

Back 84

cytoplasm

Front 85

In eukaryotes, transcription occurs in the ________

Back 85

nucleus

Front 86

" ATGCTATTG " is an example of a code for DNA or RNA? How can you tell?

Back 86

DNA: presence of thymines

Front 87

" AUGCUAUUG " is an example of a code for DNA or RNA? How can you tell?

Back 87

RNA: presence of uracil

Front 88

In DNA, adenine pairs with __________.

Back 88

thymine

Front 89

In RNA, adenine pairs with __________.

Back 89

uracil

Front 90

an MRNA is read in what direction?

Back 90

5'------->3'

Front 91

There are _____ codons.

Back 91

64

Front 92

In prokaryotes, __________ can begin before transcription is complete.

Back 92

translation

Front 93

In _________, translation can begin before transcription is complete

Back 93

prokaryotes

Front 94

Genes for the enzymes in glycolosis are examples of what type of enzymes?

Back 94

constitutive enzymes

Front 95

The start codon codes for the amino acid _________.

Back 95

methionine

Front 96

Another word for the stop codon is a ________ codon.

Back 96

nonsense