Lecture 2- Prokaryotes Flashcards

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1
Q

A(n) _____ is a small, extrachromosomal DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently.

A

Plasmid

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2
Q

What organism is thought to be the ancestor of chloroplasts?

A

Cyanobacteria

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3
Q

Which domain do methanogens belong to?

A

Archaea

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4
Q

Which type of horizontal gene transfer involves the incorporation of foreign DNA as plasmids or into bacterial genome?

A

Transformation

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5
Q

_____ is a carbohydrate polymer consisting of sugars and amino acids that forms a mesh-like layer outside the plasma membrane of most bacteria, forming the cell wall

A

Peptidoglycan

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6
Q

What is the difference between positive and negative taxis?

A

Positive taxis is movement towards a stimulus, whereas negative taxis is movement away from a stimulus

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7
Q

What color do gram-positive bacteria appear after gram staining?

A

Purple

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8
Q

How do prokaryotes reproduce?

A

Binary fission

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9
Q

True or False: Both prokaryotic and eukaryotic flagella are covered by a plasma membrane

A

False; only eukaryotic flagella are covered by plasma membrane

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10
Q

What color do gram-negative bacteria appear after gram staining?

A

Pink

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11
Q

What is the difference between vertical gene transfer and horizontal gene transfer?

A

Vertical gene transfer is the transfer of genetic material from parent to offspring, whereas horizontal gene transfer is the transfer of genetic material NOT from parent to offspring

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12
Q

______ is the process by which foreign DNA is introduced into a cell by a virus

A

Transduction

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13
Q

True or False: Cell walls of plant cells contain peptidoglycan

A

False; peptidoglycan is exclusive to bacteria

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14
Q

What is the most recent ancestor of the mitochondria?

A

Alpha proteobacteria

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15
Q

What are halophiles?

A

Extremophiles that thrive in high salt concentrations

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16
Q

Why do gram-positive bacteria appear purple after gram staining?

A

Due to the thick peptidoglycan layer in their cell wall

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17
Q

______ is the genetic alteration of a cell resulting from the direct uptake and incorporation of exogenous genetic material from its surroundings through the cell membrane(s)

A

Transformation

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18
Q

A(n) ____ _____ is an organism that makes ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation or anaerobic respiration if oxygen is absent

A

Facultative anaerobe

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19
Q

What are thermophiles?

A

Extremophiles that thrive in high temperatures

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20
Q

What is the outer membrane of gram-negative bacteria composed of?

A

Lipopolysaccharides (LPS) and a thin peptidoglycan layer

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21
Q

______ is the transfer of genetic material between bacterial cells by direct cell-to-cell contact

A

Bacterial conjugation

22
Q

A gram stain is conducted and the bacteria appears pink in color. What type of bacteria has been stained?

A

Gram-negative

23
Q

True or False: Binary fission is the source of genetic diversity in prokaryotes

A

False; binary fission produces identical copies

24
Q

A(n) _____ is a hair-like appendage required for bacterial conjugation

A

pilus

25
Q

A gram stain is conducted and the bacteria appears purple in color. What type of bacteria has been stained?

A

Gram-positive

26
Q

Transformation, transduction, and conjugation are all mechanisms of ________

A

horizontal gene transfer

27
Q

Which domain do extremophiles belong to?

A

Archaea

28
Q

Describe the cellular organization of prokaryotes

A

Smaller than eukaryotes, simpler than eukaryotes, lack membrane bound organelles, plasma membrane often folded inward, contains enzymes for respiration and photosynthesis

29
Q

Purpose of cell wall in prokaryotes

A
  • Protects cell
  • Maintains shape
  • Prevents bursting
30
Q

Gram _________ bacteria have a thick wall, composed of peptidoglycan

A

Positive

31
Q

Gram ___________ bacteria have a thin peptidoglycan inner layer and a lipopolysaccharide (LPS) outer membrane

A

Negative

32
Q

Gram ________ often more likely to cause serious disease

A

Negative

33
Q

Flagella

A

Most common motility structure in prokaryotes. Found in bacteria, archaea, eukaryotes. Similar function but arose independently (convergent evolution-> analogous structures)

34
Q

Prokaryotic vs. Eukaryotic flagella

A

Prokaryotic flagella is 1/10th as wide as eukaryotic flagella and is not covered with plasma membrane. They differ in mechanism and structure

35
Q

Flagellum function

A

H+ pump across plasma membrane by electron transport chain, forms gradient, H+ diffuses through motor, energy from diffusion turns motor (Proton motive force)

36
Q

Prokaryotic reproduction

A

Reproduce by binary fission, asexual (1 cell divides into 2), under optimal conditions very rapid

37
Q

What promotes genetic diversity in prokaryotes?

A

Rapid reproduction and mutation

38
Q

How does genetic recombination work in prokaryotes?

A

Prokaryotes do not go through meiosis. Instead, they have recombination between cells: Horizontal gene transfer

39
Q

Transformation

A

Prokaryotic cell takes up foreign DNA from environment

40
Q

Transduction

A

Phages transfer prokaryotic genes from one cell to another

41
Q

What are the 3 recombination mechanisms?

A

Transformation, transduction, and conjugation

42
Q

Conjugation

A

An F+ cell with the F (fertility) factor sends a pilus to an F cell (lacking the F factor). The F factor is then copied and transferred to the F cell, converting it into an F+ cell as well. This process can also result in the transfer of chromosomal DNA, contributing to genetic diversity among bacterial populations.

43
Q

Where do phototrophs get their energy from?

A

Light

44
Q

Where do chemotrophs get their energy from?

A

Chemicals

45
Q

What carbon source do autotrophs need?

A

CO2 or other inorganic carbon (because they are producers)

46
Q

What carbon source do heterotrophs need?

A

Organic carbon e.g. glucose (because they are consumers)

47
Q

Obligate anaerobes

A

Poisoned by O2

48
Q

Obligate anaerobes

A

Poisoned by O2, 2 alternatives:
Fermentation- make ATP without ETC
Anaerobic respiration- ATP with ETC, different e- acceptor

49
Q

What are thermophiles/hyperthermophiles?

A

Extremophiles that thrive in hot environments

50
Q

What are methanogens?

A

Extremophiles- release methane as a byproduct of metabolism. Obligate anaerobes, often in swamps and marshes