1
Q
Genome
A
-the entire genetic complement of an organism , includes its genes and nucleotide sequences
2
Q
Chromosome
A
-DNA wrapped around proteins, takes up little space in the cell
3
Q
Haploids
A
-one copy of chromosomes
4
Q
diploid
A
- two copies of chromosomes
5
Q
Prokaryotic
A
- usually 1 circular chromosome therefore haploid
- chromosomes in nucleoid region
- often they also contain plasmids
6
Q
Eukaryotic
A
- multiple linear chromosomes usually diploid but some haploid or polyploid
- nuclear and some extranuclear chromosomes (mitochondria)
7
Q
What are chromosomes made of in both eukaryotic and prokaryotic organisms?
A
-DNA and proteins
8
Q
Plasmids
A
-are small circular DNA molecules which replicate independently from the nucleoid and often code for one or more additional cellular traits
-are not essential for normal growth, metabolism, or reproduction but can offer additional survival advantages
-some fungi and protozoa can carry plasmids
-help bacteria survive a very specific situation but not needed to live
9
Q
Types of plasmids
A
- Fertility factors (F+/F-) (conjugation ability-gene that makes sex pili)
- Resistance factors (R+/R-) (resistance to antibiotics)
- Bacteriocin factors (B+/B-) (protein that kills other bacteria) (toxin production)
4.Virulence plasmids (V+/V-) (pathogenicity- ability to infect) - cryptic plasmids (no one knows their function)
10
Q
RNA
A
-single stranded
-does not have thymine but uracil
- AU go together and GC
-sugar is ribose
11
Q
DNA
A
-double stranded
-contains adenine, guanine, cytosine, and thymine
- AT go together and GC
-sugar is deoxyribose
12
Q
DNA replication
A
-is an anabolic process, therefore it requires both monomers and energy
-triphosphate deoxyribonucleotides serve both functions
-has antiparallel strands that are synthesized differently
13
Q
What is the key to replication of the bases?
A
complementarity
14
Q
Is replication semiconservative or conservative?
A
semiconservative
15
Q
Semiconservative
A
-the replicated DNA is part old and part new strand of the double helix. Has old parent strand and newly made strand
16
Q
Leading strand is synthesized how?
A
continuously
17
Q
Lagging strand is synthesized how?
A
discontinuously
18
Q
Which direction can polymerases add nucleotides?
A
-only 5’ to 3’ to the free 3’ OH group on a carbon
19
Q
Initial steps in DNA replication
A
- Helicase unwinds the double helix
- stabilizing proteins or SSBP (single stranded binding proteins) stabilize the replication fork (keeps it from snapping back)
3.DNA polymerase III begins syntheses at the 3’ OH site of primers and proofreads/repairs as it adds bases (only add on 1 side) - DNA polymerase I then removes primers, replaces the primers with DNA
- Ligase completes the backbone
20
Q
Primase
A
-produces short RNA primers
-act as a seat for DNA polymerase III
21
Q
Topoisomerase
A
-helps to relieve tension that comes from unwinding by helicase of DNA
22
Q
Name the 5 enzymes involved in DNA replication
A
- DNA polymerase III
- DNA polymerase I
- Topoisomerase
- Primase
- Ligase
23
Q
What are stabilizing proteins (SSBP)
A
-these are stabilizing proteins and they help stabilize the replication fork (keep it from snapping back)
24
Q
antiparallel strand orientation
A
-the strands of DNA double helix are antiparallel because they have the same chemical structure but opposite directions
- one strand 5’ to 3’ and the other strand is 3’ to 5’
25
What forms because of the lagging strand discontinuous nature
-okazaki fragments
26
promoter
-tells the cell where the gene starts
27
terminator
-tells the gene where the cell ends
28
genotype
DNA sequence
29
phenotype
Physical characteristics
30
Transcription
Turning DNA into RNA
31
translation
Turning RNA to protein
32
Central dogma
DNA ----> RNA ---> Protein
33
Events that happen in both eukaryotes and prokaryotes for transcription
-Four types of RNA must be transcribed from DNA, (RNA primers, mRNA, rRNA, and tRNA
-RNA transcription first requires the enzyme RNA polymerase and it occurs in three steps
1. initiation
2. elongation
3. termination
34
What are the four types of RNA that must be transcribed from DNA
RNA primers, mRNA, tRNA, rRNA
35
What are the three main steps in RNA transcription
1. Initiation
2. Elongation
3. Termination
36
Initiation
starting transcription require a promoter sequence and a RNA polymerase to begin
-also requires mRNA, small rRNA subunit, a start codon (AUG), and transfer RNA delivering methionine with the tRNA anticodon UAC
37
Elongation
needs RNA polymerase and nucleotides
-adds the large subunit of rRNA and multiple tRNA's deliver the amino acid to the initiation complex above
38
Termination
needs a terminator sequence to end
-needs a stop codon sequence
39
What do you need for transcription and translation
mRNA, tRNA, Ribosomes
40
Transcription for Eukaryotes only
-most RNA transcription occurs in the nucleus but transcription occurs in mitochondria and chloroplast
-there are at least three types of RNA polymerases
-numerous transcription factors are involved
-mRNA is extensively processed before translation (for protection)
-goes through 5' capping (Guanine), 3' poly A tail (adenine), and splicing (removal of introns)
41
transcription factors
-alert RNA polymerase
42
Transcription for prokaryotes
-occurs in the nucleoid region of prokaryotes within the cytoplasm and no processing of the mRNA
43
Introns
-are unnecessary regions that need to be removed, do not code for proteins
44
Where are proteins transcribed?
ribosomes
45
exons
-expressed sequences
46
Events in translation for both Prokaryotes and Eukaryotes
-they both have initiation, elongation, and termination
47
Translation
-involves three steps that convert an mRNA sequence into a polypeptide sequence of amino acids
48
Codons to know
1. AUG (start)
2.UAC (anticodon)
3. UAG (stop)
4. UAA (stop)
5. UGA (stop)
49
Mutation
-any change in the nucleotide base sequence of a genome, mutation are rare
-they are almost always deleterious and rarely lead to a protein having a novel property that improves its ability for descendants to survive and reproduce
-happen in DNA but will be reflected in RNA
-most are repaired by enzymes like base excision/ mismatch repair
50
List of point mutations
1. insertion
2. deletions
3. substitutions
*these are the most common
51
Frameshift mutations
- mutation that changes the reading frame
-can be done by insertion or deletions
-very bad
52
translocations
non point mutations possibly involving portions of genes or entire genes
-less common
53
silent mutation
-mutation but protein remains the same
54
missense mutation
A substitution in a nucleotide sequence resulting in a codon that specifies a different amino acid: What is transcribed makes sense but not the right sense.
55
nonsense mutation
A substitution in a nucleotide sequence that causes an amino acid codon to be replaced by a stop codon
56
wildtype
-most common form
57
ionizing radiation
- induces breaks in the chromosomes
58
nonionizing radition
-induces pyrimidine dimers (Thymine dimers)
* too much UV exposure can cause these
59
nucleotide analogs
disrupts DNA and RNA replication and cause point mutations
60
List of chemical mutagens
1. nucleotide analogs
2. nucleotide-altering chemicals
3. frameshift mutagens
61
nucleotide-altering chemicals
results in base pair substitution mutation and missense mutations
62
frameshift mutagens
-results in nonsense mutation
63
mutants
-descendants of a cell that have not successfully repaired a mutation
64
Positive selection
directly selects for mutated cells (ex: penicillin mutants)
65
negative selection
indirectly selects for trp auxotroph, this is a multistep process
66
Ames test
-salmonella and His+ --> His- mutants used as a mutagen "pre-screen"
-Method for screening mutagens that is commonly used to identify potential carcinogens
-if the substance causes mutations it will revert His- back to His+
67
His+
has the ability to synthesize histamine
68
His-
not not synthesize histamine
69
Recombinants
cells with DNA molecules that contain new nucleotide sequences
70
Vertical gene transfer
-organisms replicating their genomes providing copies to a descendant (normal)
71
horizontal gene transfer
-a donor contributes part of its genome to a recipient cell
-transfer to another cell but not apart of reproduction
-happens in bacteria
72
Three types of horizontal gene transfer
1. transformation
2. transduction (general and specialized)
3. Bacterial conjugation
73
transformation
Griffith and s.pneumoniae
74
Transduction
a bacteriophage transfers the DNA
75
general transduction
-the transducing phage carries random DNA segments from donor to recipient
76
specialized transduction
toxin transfer (E.coli O157/H7)
-only certain donor DNA sequences are transferred, such as a gene
77
bacterial conjugation
an F factor for pilus production, R factor for resistance transfer
78
Griffith's experiment observations
1. observed streptococcus pneumoniae
-injected mouse with live strain s, mouse died
-injected mouse with heat treated dead strain s, mouse lives
-injected mouse with strain r cells, mouse lives
** these are the controls
79
strain s
-has capsule
80
strain r
- has no capsule
-non pathogenic
81
griffiths experiment
-originally trying to develop an vaccine
1.Injected a mouse with the living strain R (non pathogenic) and heat treated dead strain s cells
2. The mouse dies (this was not expected)
3. Get a culture of streptococcus from the dead mouse
4. Found living cells with capsule strain s
-concluded something from the heat treated stain s cells transformed the living harmless R strain to be pathogenic s-strain (he did not know it was DNA)
82
In-vitro transformation (Griffith)
1. Heat treated cells of strain s added to a test tube
2. some cells take up DNA from the environment and incorporate it into their chromosomes
3. transformed cells acquire ability to synthesize capsule
83
What was the transforming agent in Griffiths experiment
-DNA, this was found out by (Avery, McCarthy, and MacLeod)
-one of the conclusive pieces of proof DNA is the genetic material in cells
84
competent
-cells that take up DNA
-results from alterations in cell wall and cytoplasmic membranes that allows DNA to enter cells
84
Steps of transduction
1.phage inject DNA
2. phage enzymes degrade host DNA
3. cell synthesizes new phages that incorporate phage DNA and some host DNA
4. move to a new cell and transducing phage injects donor DNA
5. donor DNA is incorporated into the recipient's chromosomes by recombination
85
Bacterial conjugation steps
1. donor cell attaches to a recipient cell with its pilus, this draws the cells closer
2. the cells contact one another
3.one strand of plasmid DNA transfers to the recipient
4. the recipient synthesizes a complementary strand to become an F+ cell, the donor synthesis a complementary strand to restore its complete plasmid
86
E (tRNA) exit site
The E site serves as a threshold. It holds the tRNA without its amino acid, which is then released by ribosome
87
A (tRNA) add
The A site binds to the incoming aminoacyl tRNA, which carries the new amino acid to be added to the polypeptide chain.
88
P (tRNA) polypeptide
The P site holds the tRNA with the growing polypeptide chain.
Microbiology
flashcards
Decks in class (13)
# Cards
-
Early years of microbiology50
-
Cell structure and function52
-
Chapter 4: Microscopy Staining and Classification37
-
Chapter 11: Characyerizing and classifying prokaryotes75
-
Chapter 9 : Controlling microbial growth102
-
Chapter 7: microbial genetics89
-
Chapter 15: Innate immunity27
-
Chapter 16: Third line of defense56
-
Chapter 14: Infection, Infectious Diseases, and Epidemiology100
-
chapter 13: Characterizing Viruses33
-
Chapter 20: pathogenic gram negative cocci and bacilli30
-
Chapter 22: Pathogenic Fungi49
-
Chapter 23: Parasitic protozoans and helminths39
