BIO 225 Unit 2

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Micro Test 2
Grade levels:
College: Second year
Subjects:
microbiology
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1

Genetics

The study of what genes are, how they carry information, how information is expressed, and how genes are replicated.

2

Gene

A segment of DNA that encodes a functional product, usually a protein.

3

Genome

All of the genetic material in the cell

4

Genotype

The genes of an organism

5

Phenotype

Expression of genes

6

Mutagen

Agent that causes mutation

7

Spontaneous Mutations

Occur in the absence of a mutagen

8

Base Pair

The arrangement of nitrogenous bases in nucleic acids based on hydrogen bonding; in DNA, base pairs are A-T and G-C; in RNA, base pairs are A-U and G-C

9

Base Substitution

The replacement of a single base in DNA by another base, causing a mutation; Also called a point mutation

10

Carcinogen

Any cancer-causing substance

11

Conjugation

The transfer of genetic material from once cell to another involving cell-to-cell contact

12

Codon

A sequence of three nucleotides in mRNA that specifies the insertion of an amino acid into a polypeptide

13

DNA Polymerase

Enzyme that synthesizes DNA by copying a DNA template

14

Degeneracy

Redundancy of the genetic code; that is, most amino acids are encoded by several codons

15

F (Fertility) Factor

A plasmid found in the donor cell in bacterial conjugation

16

Genetic Recombination

The process of joining DNA from different sources

17

Frameshift Mutation

A mutation caused by the addition or deletion of one or more bases in DNA

18

Genetic Code

The mRNA codons and the amino acids they encode

19

Inducer

A chemical or environmental stimulus that causes transcription of specific genes

20

Induction

The process that turns on the transcription of the gene

21

Hfr Cell

A bacterial cell in which the F factor has become integrated into the chromosome; Hfr stands for high frequency recombination

22

Mutation Rate

The probability that a gene will mutate each time a cell divides

23

Missense Mutation

A mutation that results in the substitution of an amino acid in a protein

24

Mutation

Any change in the nitrogenous base sequence of DNA

25

Negative Selection

(Indirect) The process of identifying mutations by selecting cells that do not grow using replica plating

26

Nonsense Mutation

A base substitution in DNA that results in a nonsense codon

27

Nonsense Codon

A codon that does not encode any amino acid

28

Positive Selection

(Direct) A procedure for picking our mutant cells by growing them

29

Promoter

The starting site on a DNA strand for transcription of RNA by RNA polymerase

30

Semi-conservative Replication

The process of DNA replication in which each double-stranded DNA molecule contains one original strand and one new strand.

31

Transcription

The process of synthesizing RNA form a DNA template

32

mRNA

The type of RNA molecule that directs the incorporation of amino acids into proteins

33

Terminator

The site on a DNA strand at which transcription ends

34

Translation

The use of mRNA as a template in the synthesis of protein.

35

Sense Codon

A codon that codes for an amino acid

36

tRNA

The type of RNA molecule that brings amino acids to the ribosomal site where they are incorporated into proteins

37

Anticodon

The there nucleotides by which a tRNA recognizes an mRNA codon

38

Repression

The process by which a repressor protein can stop the synthesis of a protein

39

Operator

The region of DNA adjacent to structural genes that controls their transcription

40

Operon

The operator and promoter sites and structural gens they control

41

Repressor

A protein that binds to the operator site to prevent transcription

42

Psycrophiles

An organism that grows best at about 15C and does not grow above 20C; a cold-loving microbe

43

Mesophiles

An organism that grows between about 10C and 50C; a moderate temperature-loving microbe

44

Thermophiles

An organism whose optimum growth temperature is between 50-60 C; a heat loving microbe

45

Psycrotrophs

An organism that is capable of growth between about 0C and 30C

46

Adicophiles

A bacterium that grows below pH 4

47

Nitrogen Fixation

The conversion of Nitrogen into ammonia

48

Trace Elements

A chemical element required in small amounts for growth

49

Obligate Aerobes

An organism that requires molecular oxygen to live

50

Facultative Anaerobes

An organism that can grow with or without molecular oxygen

51

Obligate Anaerobes

An organism that does not use molecular oxygen and is killed in the presence of oxygen

52

Superoxide Dismutase

(SOD) an enzyme that destroys superoxide

53

Peroxidase

An enzyme that destroys hydrogen peroxide

54

Catalase

An enzyme that breaks down hydrogen peroxide

55

Aerotolerant Anerobes

An organism that does not use molecular oxygen but is not affected by its presence

56

Microaerophiles

An organism that grows best in an environment with less molecular oxygen than is normally found in air

57

Culture Medium

The nutrient material prepared for growth of microorganisms in a laboratory

58

Sterile

Free of microorganisms

59

Chemically Defined Medium

A culture medium in which the exact chemical composition is known

60

Complex Media

A culture medium in which the exact chemical composition is not known

61

Capnophiles

A microorganism that grows best at relatively high carbon dioxide concentrations

62

Colony

A visible mass of microbial cells arising from one cell or from a group of the same microbes

63

Selective Media

A culture medium designed to suppress the growth of unwanted microorganisms and encourage growth of desired ones

64

Differential Media

A solid culture medium that makes it easier to distinguish colonies of the desired organism

65

Lyophilization

Freezing a substance and sublimating the ice in a vacuum; also called freeze-drying

66

Generation Time

The time required for a cell or population to double in number

67

Log Phase

The period of bacterial growth or logarithmic increase in cell numbers; also called exponential growth phase

68

Lag Phase

The time interval in a bacterial growth curve during which there is no growth

69

Stationary Phase

The period in a bacterial growth curve when the number of cells dividing equals the number dying

70

Death Phase

The period of logarithmic decrease in a bacterial population; also called logarithmic decline phase

71

Turbidity

The cloudiness of a suspension

72

Antiseptic

Removal of pathogens from living tissue

73

Alcohol

An organic molecule with the functional group --OH

74

Commercial Sterilization

A process of treating canned goods aimed at destroying the endospores of Clostridium botulinum

75

Degerming

The removal of microorganisms in an area

76

Dessication

The removal of water

77

Disinfection

Any treatment used on inanimate objects to kill or inhibit the growth of microorganism; a chemical used is called a disinfectant

78

Germicide

Kills microbes (biocide)

79

Bacteriostat

Inhibiting, not killing microbes

80

Nonionizing Radiation

Short-wavelength radiation that does not cause ionization; UV is an example

81

Halogens

One of the following elements: fluorine, chlorine, bromine, iodine, or astatine

82

Ionizing Radiation

High-energy radiation with a wavelength less than 1nm; causes ionization. X rays and gamma rays are examples

83

Phenol

OH also called carbolic acid

84

Pasteurization

The process of mild heating to kill particular spoilage microorganisms or pathogens

85

Sterilization

Removal of all microbial life

86

UHT Pasteurization

A method of treating food with high temperatures for very short times to make the food sterile to that it can be stored at room temperature (Ultra-high-temperature)

87

Sanitation

Lower microbial counts on eating utensils

88

HTST Pasteurization

Pasteurizing at 72C for 15 seconds (High-temperature short-time)

89

Hot Air Sterilization

Sterilization by the use of an oven at 170C for approximately 2 hours

90

Antifungal

no more fungus

91

Antiretroviral

no more retrovirals

92

Antiviral

no more virus

93

Broad Spectrum

An antibiotic that is effective against a wide range of both gram-positive and gram-negative bacteria

94

Chemotherapy

Treatment of disease with chemical substances

95

Narrow Spectrum

An antibiotic that is effective on either gram-positive OR gram-negative

96

Penicillin

A group of antibiotics produced either by Penicillium or by adding side chains to the B-lactam ring

97

Protease Inhibitor

An inhibitor that inhibits the enzyme that digests proteins

98

Selective Toxicity

The property of some anitmicrobial agents to be toxic for a microorganism and nontoxic for the host

99

Synergism

The principle whereby the effectiveness of two drugs used simultaneously is greater than that of either drug used alone

100

Superinfection

The growth of a pathogen that has developed resistance to an antimicrobial drug being used; the growth of an opportunistic pathogen