Chapter 9 - Microbial Genetics Flashcards
(104 cards)
1
Q
What is the transmission of biological properties (traits) from parents to offspring, how those traits are expressed, the structure and function of genetic material, and how this material changes is known as?
A
Genetics
2
Q
Define Genetics
A
The study of inheritance or heredity
3
Q
Define Genome
A
The sum total of genetic material of an organism
4
Q
What is Genomics?
A
The study of an organism’s entire genome
5
Q
How may genomes appear?
A
Most exists in the form of chromosomes and
Some may appear in nonchromosomal forms:
6
Q
What are some non chromosomal form that genome can appear as?
A
Plasmids: tiny extra pieces of DNA
Organelles: mitochondria and chloroplasts
7
Q
What are basic informational packets called?
A
Genes
8
Q
What is a functional unit of heredity called?
A
Classical genetics
9
Q
What is molecular and biochemical genetics?
A
Site on the chromosome that provides information for a certain cell function
10
Q
What is a preferred definition of genes?
A
A segment of DNA that contains the necessary code to make a protein or an RNA
11
Q
Define genotype
A
The sum of all types of genes constituting an organism’s distinctive genetic makeup
12
Q
What is the expression of the genotype that creates certain structures or functions?
A
Phenotype
13
Q
What is the basic unit of DNA?
A
Nucleotide
14
Q
What is a nucleotide?
A
Phosphate, Deoxyribose sugar, and Nitrogenous base
15
Q
What are purines and pyrimidines?
A
Nitrogenous bases
16
Q
What nitrogenous base is found in DNA and RNA?
A
Purines
17
Q
What pyrimidines are found in DNA?
A
Cytosine and Thymine
18
Q
What pyrimidines are found in RNA?
A
Cytosine and Uracil
19
Q
What binds to Guanine and Adenine in RNA?
A
Guanine to Cytosine and Adenine to Uracil
20
Q
What binds to Adenine and Guanine in DNA?
A
Adenine to Thymine and Guanine and Cytosine
21
Q
What enzyme adds bases to the new DNA chain; proofreading the chain for mistakes?
A
DNA polymerase III
22
Q
A template strand is an original?
A
Parental DNA Strand
23
Q
Each parent DNA strand serves as a?
A
Template for synthesis of New DNA strands
24
Q
Semiconservative replication is?
A
Each daughter molecule is identical to the parent in composition, yet neither is completely new
25
What synthesizes a new daughter strand of DNA using the parental strand as a template?
DNA polymerase III
26
DNA must be _______ and ______ before DNA polymerase III can function.
Unwound
| Separated
27
DNA polymerase III can only add _________ to an existing chain- cannot begin _________ a chain of nucleotides but can only add nucleotides in the 5’ to 3’ _______.
nucleotide
synthesizing
direction
28
Define replication fork
The place in the helix where the strands are unwound and replication is taking place
29
How many Replications forks will a circular DNA molecule have?
Two
30
What is a length of RNA that is inserted initially during replication before being replaced by DNA known as?
Primer
31
What is the strand of new DNA that is synthesized continuously in a 5’ to 3’ direction known as?
Leading strand
32
The strand of new DNA that must be synthesized in short segments and is Later sealed together to form a strand in the 3’ to 5’ are know as?
Lagging strand
33
In what direction does the new DNA that is synthesized in short segments process through?
In the 5’ to 3’ direction
34
What are Okazaki fragments?
Short segments of DNA synthesized in a 5’ to 3’ direction which are then sealed together to form the 3’ to 5’ strand
35
What is the “Central Dogma” of genetics?
It is the process of turning DNA into proteins
36
The first step of the “Central Dogma theory is known as?
Transcription- DNA is used to synthesize RNA
37
What is the second step to the “Central Dogma” theory?
Translation- RNA used to produce proteins
38
Is the “Central Dogma” complete or incomplete?
Incomplete
39
What is used to regulate gene function?
A wide variety of RNAs
40
What is “Junk” DNA?
The DNA that codes for these crucial RNA molecules used to regulate gene function
41
Where are many genetic malfunctions that cause human disease found?
In regulatory RNA and not in genes for proteins
42
What determines a an organisms characteristic shape and function?
A protein’s primary structure
43
What determines phenotype?
Proteins
44
What is proteomics?
the study of an organism’s complete set of expressed proteins
45
DNA is mainly a blueprint that tells the cell?
Which kinds of proteins to make and how to make them
46
What does tRNA stand for?
Transfer RNA
47
What is a tRNAs function in a cell?
Brings amino acids to ribosomes during translation
48
What codes does tRNA contain?
A cloverleaf tRNA to carry amino acids
49
What is known as a transcript of structural gene or genes in the DNA and is synthesized in a process similar to synthesis of the leading strand during RNA replication?
mRNA
50
What has a function that is a series of triplet bases that hold the message of the transcribed mRNA?
Codons
51
What contains sequences of bases that form hydrogen bonds with complementary sections of the same tRNA strand?
tRNA
52
What designates the specificity of the tRNA and complements the mRNA codon and is found at the bottom loop of the cloverleaf?
Anticodon
53
What is a long polynucleotide molecule, that forms complex three-dimensional shapes that contribute to the structure and function of ribosomes?
rRNA
54
The interaction of rRNA and protein create?
The two subunits of the ribosome that engage in final translation of the genetic code
55
How are mRNA nucleotides read?
They are read in codons, or groups of three
56
What dictates which amino acids are added to the growing chain?
The codon
57
Is the message in messenger RNA universal?
This code is universal for bacteria, archaea, eukaryotes, and viruses
58
What allows for the insertion of correct amino acids even when mistakes occur in the DNA sequence?
Redundancy
59
Define Redundancy
Certain amino acids are represented by multiple codons.
60
What does it mean when only the first two nucleotides are required to encode the correct amino acid, with the third nucleotide not changing its sense, and permits some variation or mutation without altering the message?
Wobble
61
What are the elements needed to synthesize a protein?
Amino acids
Ribosome
mRNA
tRNA
62
What are the three stages of transcription?
Initiation
Elongation
Termination
63
What are the first three RNA nucleotides that signal the beginning of the message called?
Start Codon, always AUG
64
What is translocation?
The process of shifting the ribosome down the mRNA strand to read new codons
65
What are one of three codons that has no corresponding tRNA and causes translation to be terminated known as?
Stop Codon
66
How many stop codons are there and what are they?
Three: UAA, UAG UGA
67
What is it called when Proteins begin to fold upon themselves to achieve their tertiary conformation even before the peptide chain is released?
Posttranslational modifications
68
Formyl methionine may be clipped off, cofactors may be added, and some join with other proteins to form a quaternary structure are considered part of what?
Posttranslational modifications that complete protein synthesis
69
What does not exist in an uninterrupted series of codons coding for a protein?
Most eukaryotic genes
70
What is a coding region called?
Exxon’s
71
What are intervening sequences of bases that do not code for protein called?
Introns
72
What are a coordinated set of genes regulated as a single unit, can be inducible or repressible, categories determined by how transcription is affected by the environment surrounding the cell, and is found only in bacteria and archaea?
Operons
73
What are inducible operons?
Operon is turned on (induced) by the substrate(s) for which the structural genes encode
74
What kind of operon is a catabolic operon that encodes enzymes that act in catabolism and the enzymes needed to metabolize a nutrient are only produced when that nutrient is present in the environment?
Inducible Operons
75
What is a repressible operon?
Operon that contain genes coding for anabolic enzymes
76
What is describes as several genes in a series that are turned off by product synthesized by the enzyme?
Repressible operons
77
What is a regulator in the lac operon?
Feature of the lac operon composed of the gene that codes for the repressor, a protein capable of repressing the operon
78
What two features does control locus have?
Promoter and Operator
79
What recognizes a promoter in the control locus?
Recognized by RNA polymerase
80
What acts as an on/off switch for transcription?
Operator
81
Define structural locus
made up of three genes, each coding for a different enzyme needed to catabolize lactose
82
What protein in the Lactose Operon is allosteric?
The repressor protein
83
What is the binding sites for the operator sequence on the DNA and lactose?
The repressor protein
84
In the absence of lactose what does the repressor do?
Binds to the operator, blocking transcription of structural genes
85
What are plasmids?
Extrachromosomal DNA adept at moving between cells
86
Define recombinant
any organism that contains and expresses genes that originated in another organism
87
What is described as an event in which one bacterium donates DNA to another bacterium and the end results is a strain different from both the donor ad the recipient strain?
Recombination
88
What is any transfer of DNA that results in organisms acquiring new genes that did not come directly from parent organisms?
Horizontal gene transfer
89
What is described as a small circular pieces of DNA that can replicate independently of the bacterial chromosome?
Plasmids
90
What is found in most bacteria and in some fungi, contains at most a few dozen genes, and allow transfer of DNA between cells?
Plasmids
91
What is not necessary for cell survival but often carry useful traits?
Plasmids
92
Resistance plasmids carry genes for resisting _______ or other drugs, commonly shared among bacteria through __________, can confer multiple resistance to antibiotics, and _ factors can also carry _______ codes for resistance to heavy metals, or ____________ virulence factors.
```
antibiotics
conjugation
R
genetic
synthesizing
```
93
What is described as the acceptance by a bacterial cell of small fragments of soluble DNA from the surrounding environment?
Transformation
94
What is competent?
Cells that are capable of accepting genetic material through transformation
95
What is the process by which a bacteriophage serves as a carrier for DNA from a donor cell to a recipient cell?
Transduction
96
Transduction occurs in a broad _______ of bacteria and the participating ______ in a single transduction event must be the same species.
spectrum
bacteria
same
97
When are random fragments of disintegrating host DNA taken up by a phage?
Assembly
98
What kind of part of the host genome is regularly incorporated into the virus?
A highly specific part
99
What separate from the chromosome carrying host genes with it?
The Prophage DNA
100
Define Mutation
Any permanent change to the nucleotide sequence in the genome
101
What is the driving force of evolution?
Mutations
102
What becomes evident in altered gene expressions?
Mutations such as altered pigment production or development of resistance to a drug
103
Define spontaneous mutation
A random change in the DNA arising from errors in replication that occur randomly
104
What is the result from exposure to known mutagens?
Induced mutations
