Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIO 425: Microbiology > Lecture 6/7: Growth Control and Molecular Biology > Flashcards

Lecture 6/7: Growth Control and Molecular Biology Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What are the mechanisms of drug resistance?

A
  1. Impermeability - drug can’t get into cell
  2. Efflux - infected cell ejects drug from cell w/ enzyme
  3. Inactivation - enzyme degrades drug
  4. Mutation in target - drug target mutates
  5. Absence of target
  6. Alternative Biochem pathway - cell uses different pathway to get around target of drug
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the origins of the evolution of drug resistance?

A

Drugs are produce by microorganisms b/c the microorganisms must be able to resist their own antibiotics There is no universal antibiotic Antibiotics also function as signaling molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How has antibiotic resistance spread?

A

Overuse

  • 20 percent of patients need antibiotic treatment
  • 80 percent of patients receive antibiotic treatment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How is gonorrhea a case study of antibiotic resistance?

A

Penicillin used from 1940-1990

Ciprofloxacin used in early 1990s

Ceftriaxone used in late 1990s

Antibiotics only effective as long as we have a continuous supply of new types of antibiotics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How is antibiotic resistance spread through non-medical overuse?

A

50-70 percent of antibiotics used for livestock/agriculture

We select for antibiotic-resistant bacteria by creating these antibiotic rich habitats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is an ‘‘invincible’’ pathogen? What is an example?

A

Resistance to all known microbial agents

MRSA -Methicillin-Resistant Staphylococcus aureus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How do we reverse antibiotic resistance?

A

decrease usage = decrease selection = decrease prevalence of resistance

-large scale coordinated effort

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do we deal with antibiotic resistance? What is the economic paradox of antibiotics that makes dealing with it less likely?

A

We can discover and develop new antibiotics

Economic paradox is

  • low return on investment b/c not a lifelong medicine
  • loss of value over time b/c resistance of development
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How do we discover new drugs?

A
  1. New analogs of existing compounds
  2. Computer drug design
  3. Natural products
  4. Drug combinations
  5. Bacteriophage therapy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do we use new analogs of existing compounds to search for new antimicrobial drugs?

A

Semisynthetic approach

-changing functional groups on existing compounds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How do we use computer drug design to search for new antimicrobial drugs?

A

Computer based design of new molecule to mimic/outcompete normal substrate of disease enzyme

  • competitive inhibition
  • must know very detailed information about disease like shape/structure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do we use natural products to search for new antimicrobial drugs?

A

Most antibiotics found in soil

  • actinomycetes found in soil and important for antibiotic production
  • more difficult but can find antibiotics in marine sediment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How do we use drug combinations to search for new antimicrobial drugs?

A

Using an antibiotic+compound inhibiting resistance

  • finding something that inhibits the mechanism for antibiotic resistance and combining it with an antibiotic
  • eg. efflux pump inhibitor + antibiotic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How do we use bacteriophage therapy to search for new antimicrobial drugs?

A

We use viruses to destroy specific pathogens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the functions of the different genetic elements?

A

Replication - DNA to DNA

Transcription - DNA to RNA

Translation - RNA to protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the function of DNA/RNA?

A

DNA - deoxyribonucleic acid

  • genetic blueprint for cell
  • information replication and storage

RNA - ribonucleic acid

  • converts blueprint to amino acids
  • information processing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the structure of DNA?

A

Double stranded

  • sugar-phosphate backbone
  • held together by Nitrogenous bases

Antiparallel

-5’ to 3’ and 3’ to 5’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the different types of grooves in the DNA double helix pictured?

A

Major groove and Minor grooves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How is DNA packaged into the cell? What enzyme is responsible for this?

A

DNA Supercoiling

-twisting DNA into coils takes up less space

Topoisomerases are responsible for this

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the types of Topoisomerases?

A

Class I Topoisomerases

-Single stranded break

Class II Topoisomerases

  • Double-stranded break
  • eg DNA Gyrase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

DNA is supercoiled in order to fit into cells. What needs to happen in order to access the DNA?

A

Relaxation

-for DNA transcription and replication

22
Q

What are the differences between chromosomes and plasmids?

A

Chromosomes

  • main genetic element
  • large
  • Essential genes (housekeeping)

Plasmids

  • additional genetic element
  • small
  • Non-essential genes
23
Q

How do chromosomes and plasmids transmit genetic material?

A

Chromosomes - vertical transmission

-parent to offspring

Plasmids - Vertical+Horizontal transmission

  • transmit via pili
  • don’t need to be same species
24
Q

What are R-Plasmids? What is it called when R-Plasmids are transferred to other bacteria? What are some examples?

A

R-Plasmids are resistance plasmids that confer antibiotic resistance

When transferred to other bacteria it is called CONJUGATION

Examples are B-lactamases and rRNA methylases

25
Q

What are virulence plasmids?

A

Plasmids, or secondary genetic material, that make a particular bacteria a pathogen

They confer

  1. Ability to colonize the host
  2. Ability to produce toxins

Different types of same microbe can be dangerous or good depending on virulence plasmids

26
Q

What molecules and enzymes are involved in DNA replication?

A

Molecules

  • DNA Template
  • Primer-gets new strand started
  • Nucleotides-used to build new strand

Enzymes

  • DNA Helicase-unwinds DNA
  • Primase-synthesize RNA primer on ssDNA
  • DNA Polymerase
27
Q

What is significant about prokaryotic chromosomes?

A

They are circular

  • so there are two replication forks resulting in fast DNA replication
  • called bidrectional replication
28
Q

What is Polymerase Chain Reaction?

A

DNA replication in vitro

-not entire genome, only pieces

29
Q

What are the molecules and enzymes involved in PCR?

A

Molecules

  • DNA Template
  • Primer
  • Nucleotides

Enzymes

  • Heat instead of DNA Helicase
  • Designed and added primase instead of RNA primase
  • DNA polymerase III
30
Q

What are the steps of PCR?

A
  1. Denaturing
    - Heat to 94 degrees Celsius
    - dsDNA to ssDNA
  2. Anneailng
    - Cool to 55 degrees Celsius
    - Primers bind
  3. Extension
    - Heat to 72 degrees Celsius
    - Polymerase builds DNA
  4. Repeat
    - 25-35 cycles
    - DNA Doubles each cycle=exponential growth
31
Q

What machine is responsible for PCR?

A

Thermocycler machine

32
Q

What are the applications of PCR?

A

High output of information very fast

-DNA sequencing, barcoding, identifying microbial communities

Very sensitive

33
Q

What are the nitrogenous bases of DNA/RNA?

A

DNA

-Adenine, Thymine, Cytosine, Guanine

RNA

-Adenine, Uracil, Cytosine, Guanine

34
Q

What is different about Uracil?

A
  • Similar to cytosine, 1 func group difference
  • Less stable than thymine
  • high mutation rate w/ RNA due to Uracil
35
Q

What is the structure of RNA?

A

Single stranded - one backbone

The secondary structure is formed by hydrogen bonds

-forms non-linear stems and loops

36
Q

What are the types of RNA?

A

mRNA

  • genetic info carrier
  • from genome to ribosome

tRNA

-codes for protein synthesis

rRNA

-form ribosomes, site of protein synthesis

37
Q

What molecules and enzymes are involved in the initiation step of transcription?

A

Molecules - promoter

Enzymes/Proteins - Sigma factor

  • binds to DNA at promoter region to recruit RNA polymerase
  • RNA polymerase binds to sigma factor to begin transcription
38
Q

What molecules and enzymes are involved in the elongation step of transcription?

A

RNA Polymerase begins transcription

  • sigma factor released
  • RNA chain grows
39
Q

What molecules and enzymes are involved in the termination step of transcription?

A

RNA Polymerase reaches the termination site

  • Chain growth stops
  • RNA Polymerase and newly synthesized mRNA are released from DNA template

Termination controlled by Signal DNA sequences

  1. Inverted repeats
  2. Run of Uracils
40
Q

What is different about transcription in archaea than in bacteria?

A
  1. RNA Polymerase structure
  2. Promoter region
  3. Presence of introns
41
Q

What is significant about RNA Polymerase structure in archaea?

A
  • More similar to eukaryotes
  • more complex than bacteria
42
Q

Do arachaea have introns?

A

Yes but rare

  • absent in bacteria
  • present in eukaryotes
43
Q

What are the functions of transcription, replication, translation?

A

Replication and Transcription

  • nucleic acids to nucleic acids
  • DNA to DNA OR DNA to RNA

Translation

-nucleic acids to proteins

44
Q

What is tRNA?

A

THE TRANSLATOR

  • Links codons in mRNA to Amino Acids in proteins
  • short, ssRNA

Gets its secondary structure from internal base pairing

Anticodon

-Complimentary to mRNA codon

Has Amino Acid binding site

-attaches corresponding amino acid

45
Q

What is the initiation step of translation?

A

Form Ribosome-mRNA Complex

mRNA binds at Ribosome binding site

-recognizes the Shine-Dalgarno Sequence

46
Q

What is the elongation step of translation?

A

Match tRNAs and Add Amino Acids

Amino Acids are linked by Peptide Bonds

47
Q

What is the Termination step of translation?

A

Release factors release newly synthesized protein

Recognize stop codon

48
Q

What are the levels of protein structure?

A

Primary - Amino Acid sequence

-formed by translation

Secondary - alpha helix or beta sheet

  • formed by H-bonds
  • stability, helix more stable than sheet b/c more H-bonds

Tertiary - 3D Structure

-formed by hydrophobic interactions, H, ionic, and disulfide bonds

Quaternary - greater than 1 polypeptide

-each polypeptide called a subunit

49
Q

What does protein structure determine?

A

Protein function

  • loss of structure=loss of function
  • primary structure will remain even after denaturing
50
Q

What are molecular chaperones, chaperonins?

A

Assist in protein folding

-either newly synthesized or partially denatured proteins

BIO 425: Microbiology (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions