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Microbiology > Lecture 4 > Flashcards

Lecture 4 Flashcards

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Biology 101 flashcards
1
Q

Eukaryotic flagella

A

-Back-and-forth motion
-Microtubules
-Protein subunit is tubulin

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2
Q

Archaea flagella

A

Some archaea have archaella which are composed of protein subunits known as archaellins

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3
Q

Flagella details

A

-Anchored to the cell wall and membrane by the basal body consisting of ring proteins
•Gram- have 4
•Gram+ have 2

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4
Q

Flagellar anatomy

A

-The hook
-Basal body
-Ring structures
-Mot proteins

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5
Q

The hook

A

Rotating part of the flagella

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6
Q

Basal body

A

Internal part of the flagella

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7
Q

Ring structures

A

Ring proteins attached to flagella on membrane

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8
Q

Mot proteins

A

The Mot complex in the inner cell membrane controls the flow of protons to make ATP

-Movement of flagella propel by movement of ions(+) (proton motive force PMF) down gradient through Mot proteins (no energy-gradient)

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9
Q

Gliding motility

A

-Movement without propulsive structures like flagella
-Gliding bacteria are filamentous or rod-shaped

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10
Q

Two types of gliding mobility

A
  1. Ratcheting
  2. Slime jet
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11
Q

Intracellular actin based movement

A

L. Monocytogenes can move from macrophage to macrophage without exposure to the rest of the immune system by pushing the membrane of one cell into the next.

-process of crossing from macrophage through phagocytosis then destruction of vacuole and release into cell
-moves from cell to cell without exposure to extracellular space

Ex. Listeria monocytogenes

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12
Q

Intracellular Actin-Based Movement mechanism factors

A

-actin
-VASP
-Bacterial ActA

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13
Q

Actin

A

Actin is the most abundant protein in the cytoplasm of mammalian cells (10-20%) and involved in cell motility, cell division, vesicle movement, cell shape

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14
Q

VASP

A

VASP interacts with the fast (barbed end) of actin filament to promote elongation

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15
Q

Bacterial ActA

A

Binds VASP and is connected to the expanding end of actin

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16
Q

Axial filament

A

-Also called endoflagella
-embedded between the cell wall and outer membrane
-rotates like a corkscrew

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17
Q

Filamentous appendages

A

-flagella
-fimbriae
-pili

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18
Q

Fimbriae (short attachment pili, common pili)

A

-short bristle-like and numerous
-made of fibrillin
-fimbriae are filamentous proteins with adhesive tips that allow for attachment to surfaces and other cells, colonization, and resistance flushing
-Act as virulence factors in Escherichia, Staphylococcus, and Streptococcus

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19
Q

Pilus (pili)

A

-few in number (1-10)
-longer than fimbriae
-made of pilin
-sex pili: facilitate transfer of DNA FROM ONE CELL TO ANOTHER (conjugation)

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20
Q

Eukaryote vs prokaryote rRNA count

A

Eukaryote-18 rRNA
Prokaryote-16 rRNA

21
Q

Ribosome

A

For protein synthesis (creation)

22
Q

Bacteria vs Archaea genome size

A

Bacteria 0.6-8 million base pairs
Archaea 0.5-5.6 million base pairs

E. coli—5 million nucleotides
Human —3.3 billion nucleotides

23
Q

Bacterial genetics

A

-DNA genome
•Single, circular chromosome
*some exceptions like vibrio cholera
-Haploid
-No introns (very rare)
-may have a plasmid

24
Q

Plasmids

A

An extra chromosomal self-replicating piece of DNA that carries gene for a variety of functions but is not essential for cell growth

25
Q

Types of plasmids

A

-dissimilation plasmids
-Col plasmids
-R (resistance) factors
-F (fertility factors
-Virulence factors

26
Q

Dissimilation plasmids

A

Encodes catabolic enzymes

27
Q

Col plasmids

A

Encodes bacteriocins, proteins that can kill other bacteria

28
Q

R (resistance) factors

A

Encode antibiotic resistance

29
Q

F (fertility) factor

A

Encodes sex pilus for conjugation

30
Q

Virulence factors

A

Encodes genes that increase pathogenic features

31
Q

Genetics—flow of genetic information

A

The central dogma
DNA-replication
RNA-transcription
Protein-translation

32
Q

DNA key factor

A

DNA is the blueprint for a cell’s proteins and is obtained from a parent cell or from another cell

33
Q

Replication of bacterial DNA

A

-Bacteria are haploid
-One chromosome
-Replication begins at a single origin of replication (ORI)
-Bidirectional, semiconservative replication. 5’—3’

34
Q

The process of DNA replication

A
  1. Topoisomerase (Gyrase)
  2. Helicase
  3. Single stranded binding proteins
  4. Primase
    •DNA polymerase III
  5. DNA polymerase I
  6. Ligase
35
Q

Topoisomerase (Gyrase)

A

Untwists DNA

36
Q

Helicase (DnaA)

A

Binds to Ori and unzips double helix of DNA at the replication fork to expose short single stranded region

37
Q

Single stranded binding proteins

A

Bind to stabilize and prevent reforming double helix

38
Q

Primase
•DNA polymerase III

A

Loads a primer (short stretch of RNA) complementary to DNA and DNA polymerase III attaches to synthesize new DNA 5’—3’

39
Q

DNA polymerase I

A

Removes RNA primers and replaced with DNA

40
Q

Ligase

A

Seals nicks between fragments

41
Q

The large replication complex

A

Replisome

42
Q

Drug targets

A

-Fluoroquinolones
•class of antibiotics
•Inhibit bacterial topoisomerase (gyrases)=inhibit replication

43
Q

Binary fission

A

Asexual reproduction where one parent cell divides into 2 daughter cells

44
Q

Expression of genes starts with transcription

A
  1. Initiation
  2. Elongation
  3. Termination
45
Q

Initiation

A

RNA polymerase binds to Pribnow box in the promoter region along with a protein called sigma factor. This is called the holoenzyme

46
Q

Elongation (part 1)

A

-Transcription factors help recruit or stabilize the holoenzyme (RNA polymerase & sigma) and drive transcription
•Transcription Repressor proteins are transcription factors that reduce RNA transcription
-RNA polymerase binds to DNA unwinds it (It has its own Helicase activity)
-Bacteria have one RNA polymerase, while eukaryotic cells have 3 types

47
Q

Elongation (part 2)

A

-Cab transcribe either:
•A single gene
•Co-transcribed genes—2 or more genes sharing a promoter and termination site
*Polycistronic mRNA gets cleaved into multiple mRNA products

48
Q

Termination

A

-Terminator sequences within the DNA signal the RNA polymerase to stop
-One mechanism: RNA stem-loop followed by a run of adenines

Microbiology (13 decks)

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