Brainscape's Knowledge GenomeTM

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


See full index

CELS > Module 4: > Flashcards

Module 4: Flashcards

1
Q

Main differences between bacterial and eukaryotic cells (3)

A

No nucleus
Peptidoglycan cell wall
Circular chromosome

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

What do bacterial cells have instead of a nucleus?

A

Nucleoid

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

Functions of peptidoglycan cell wall

A

Provides strength to cell with its rigidity

Protect cells from osmotic pressure/ lysis

Maintains cell shape

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

What kind of structure does peptidoglycan form in the cell wall?

A

Mesh-like

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

Two alternating units of carbohydrate backbone

A

NAG (N-acetylglucosamine)

NAM (N-acetylmuramic acid)

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

What cross-links peptidoglycan chains to form rigid cell wall in bacteria?

A

Transpeptidass (enzyme)

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

What is the cross-bridge and side chain in peptidoglycan called?

A

Peptide cross bridge

Tetrapeptide side chain

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

Gram-positive bacteria

A

Have a thick peptidoglycan layer (20-80nm) outside plasma membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Gram-negative bacteria

A

Thin layer of peptidoglycan between two membranes (plasma and outer)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Long flexible appendage that motile bacteria possess

A

Flagella

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

How does a flagella move a cell?

A

By acting as a propeller

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Three major sections of the flagellum

A

Long filament
Hook
Basal body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Long filament (flagellum)

A

End part which extends into surrounding medium

Composed of flagellin(protein) subunits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Hook (flagellum)

A

Curved section connecting the filament to the cell surface

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

Basal body (flagellum)

A

Anchors flagellum into cell membrane by plates or rings

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

Chemotaxis

A

Bacteria move along a concentration gradient toward a chemical attractant/ away from a chemical repellent

They do this as they are already moving (tumbles and runs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Fimbriae

A

Structure with adhesive properties- causes bacteria to stick to surfaces

An inherited trait

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

How do fimbriae differ from flagella? (3)

A

They are shorter, more numerous and aren’t involved in motility

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

Glycocalyx

A

Gelatinous polysaccharide and/ or polypeptide outer covering

Forms a sticky mesh work of fibres

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

Glycocalyx capsule

A

Organises and defined structures attached firmly to cell wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Glycocalyx slime layer

A

Disorganised (without cell shape) and attached loosely to cell wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Three functions of capsules (glycocalyx)

A

Virulence factors- protect bacteria from phagocytosis and being engulfed by immune cells

Adherence to cell surfaces and structures such as catheters

Prevent desiccation- drying out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

When are bacterial endospores formed and germinated?

A

During unfavourable growth conditions (formed)

Under favourable conditions (germinated)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

In which kind of bacteria are endospores present?

A

Gram-positive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are two factors that trigger endospore formation?

A

Nutrient starvation

High cell density

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Two properties of endospores

A

Resistant to heat, harsh chemicals, antibiotics, disinfectants etc.

Dormant stage of bacterial life cycle (long time)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Which domain are microorganisms in?

A

All three, but primarily prokaryotes (bacteria and archaea)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Why are prokaryotes so dominant?

A

They have a fast growth rate- the smaller the organism the faster it grows

It can evolve quickly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Binary fission

A

The process by which microorganisms can replicate themselves (one cell to two cells)

Asexual reproduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Are the daughter cells of binary fission genetically identical?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How were prokaryotes able to become dominant in history?

A

They were the sole inhabitants for about 1.7 billion years, so they could colonise most habitats

Have them extreme ecological and biological diversity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Closed batch culture system

A

A form a cell culturing

A limited supply of nutrients is provided

Cells have to change once nutrient supply is used up

We can manipulate this system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Four phases of microbial growth (feast and famine)

A

Lag
Exponential
Stationary
Death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Describe ‘feast and famine’ (microbial growth)

A

Lag phase: period between when the organism is put in, and when it starts growing
(At this point it is getting ready for growth, bio synthetic reactions are starting to run)

Exponential phase: cells are actively dividing and population is doubling at a constant time interval

Stationary phase: cryptic growth (organisms consume other cells)

Death phase: equilibrium between growing and dead cells is skewed towards death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What kind of chemical is penicillin?

A

Antibiotic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

How does penicillin work?

A

Kills bacteria by blocking cell wall synthesis

Only affects dividing cells (growing bacteria)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Persister

A

A cell that isn’t replicating

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Three things prokaryotes need to multiply

A

Carbon source (building blocks)

Energy source (electrons to drive metabolic reactions in the cell) can be chemical or light

Reducing power (molecules inside cell that can transfer energy between different parts of the cell)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Why can we call molecules ‘natures batteries’?

A

Chemical energy is stored in their bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Which is the most common energy currency in cells?

A

ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

The sun of all energy reactions inside a cell is called ____

A

Metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Catabolism

A

Breaking substrates into products (building blocks/ simpler compounds)

Releasing energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Anabolism

A

Harvesting building blocks from the environment to synthesises macromolecules and other cellular constituents

Used energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Organisms that get energy from light

A

Phototroph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Organism that gets energy from chemical compounds

A

Chemotroph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Organisms that use carbon dioxide

A

Autotroph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Organisms that get carbon from organic compounds

A

Heterotroph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Photoautotroph

A

Organism that gets energy from light and carbon from carbon dioxide

50
Q

Chemoautotroph

A

Organism that gets its energy from chemical compounds and gets its carbon from carbon dioxide

51
Q

Photoheterotroph

A

Organism that gets energy from light, and carbon from organic compounds

52
Q

Chemoheterotroph

A

Organism that gets energy from chemical compounds and carbon from organic compounds

53
Q

If there is no growth in a closed batch culture system, have all cells died?

A

No, the death rate and growth rate are in balance

54
Q

Microbial ecology

A

The study of interrelationships among microorganisms and their environment

55
Q

Microbiome

A

All microorganisms and their genes within a particular environment

56
Q

Populations of microbial species interact/ communicate to form ________

A

Communities

57
Q

Enrichment culture

A

Providing the temperature and chemical conditions in the lab that encourage the growth of specific groups of microbes

58
Q

Mesocosm

A

Experimental system that simulates real-life conditions

59
Q

Two potential goals of braking a bond (metabolism)

A

Harvesting of building blocks

Harvesting of energy

60
Q

How do intermediates play a role in bacteria redox reactions?

Example of intermediates

A

They shuttle energy from an oxidation (energy carrier)

NADH/NADPH2

61
Q

Primary producers

What do they do?

A

Autotrophs

Fix CO2 into sugars

62
Q

Decomposers

What do they do?

A

Heterotrophs

Require fixed carbon (rather than CO2), and recycle it back into CO2

63
Q

What is the process of

Carbon—> macromolecules —> cells

And what else is required for this process?

A

Anabolism

Energy

64
Q

Chemotrophs can use energy from either _____ or ______ compounds

A

Organic

Inorganic

65
Q

Which is the electron donor in redox reactions, chemical energy or light energy?

A

Chemical energy (e.g. H2S)

66
Q

Two types of photosynthesis

A

Oxygenic (non-cyclic photophsophorylation)

Anoxygenic (cyclic photophosphorylation)

67
Q

Which type of photosynthesis uses both photsystems I and II?

A

Non-cyclic/ oxygenic

68
Q

How does non-cyclic/ oxygenic photosynthesis generate oxygen?

A

Strips H2O of its electrons

69
Q

What are the energy products of non-cyclic/ oxygenic photosynthesis (2)?
How are they produced?

A

ATP (cytochrome complex)

and NADPH (electrons reduce NADP+)

70
Q

Which photosystem does cyclic/ anoxygenic photosynthesis use?

A

Photosystem I

71
Q

Product of anoxygenic/ cyclic photosynthesis

A

ATP (no O2)

72
Q

What do both cyclic and non-cyclic photosynthesis do?

A

Use light for energy and fix carbon

73
Q

How can many different microbes share the same metabolism (photosynthesis) in the same environment?

A

Light is a common resource

They absorb a specific wavelength of light to avoid competition

74
Q

How can oxygen dependent organisms live in anoxic environments?

A

Create cables to shuttle electrons into oxic zone- allows them to breathe

75
Q

Are viruses cellular or acellular?

A

Acellular

76
Q

How do viruses survive? Why?

A

By infecting a host

They have no metabolic abilities of their own

77
Q

How do viruses multiply?

A

By relying on biosynthesis machinery of host cell

78
Q

Which cells do viruses infect?

A

All types

79
Q

Two parts of a protein (sometimes third)?

A

DNA/ RNA
Capsid (protein coat)
Sometimes envelope

80
Q

Subunits of the capsid

A

Capsomers arranged in a precise pattern around the nucleic acid

81
Q

Three types of symmetry of capsomer arrangement

A

Helical
Icosahedral- 20 face polyhedron (looks like a ball)
Complex- head is icosahedral and tail is helical

82
Q

What shape can viral nucleic acid be? (3)

A

Linear
Circular
Segmented

83
Q

Four possible forms of nucleic acid in viruses

A

ssRNA
dsRNA
ssDNA
dsDNA

84
Q

Bacteriophage

What benefit could they have?

A

A virus that infects and replicates in bacteria

Potential treatment for diseases caused by bacteria

85
Q

Lyric infection (5 steps)

A
  1. Attachment- receptor recognises compatible virus
  2. Entry of phage DNA and degradation of host DNA
  3. Synthesis of viral genomes (using host nucleotides) and proteins (using host ribosomes)
  4. Self assembly
  5. Release- virus produces lysozyme which cleaves NAM-NAG bonds in peptidoglycan wall
86
Q

Lysogenic cycle

A
  1. Phage DNA integrates into bacterial chromosome
  2. Prophage is copied with bacterial chromosome
  3. Cell divisions create many infected bacteria

Sometimes a prophage exits the bacterial chromosome (still within the cell) and initiates a lyric cycle

87
Q

Prophage

A

Bacteriophage DNA within a host cell

88
Q

Lysogen/ lysogenic bacterium

A

Infected/ host bacterium in a lysogenic cycle

89
Q

How does HIV become fatal?

A

Leads to AIDS which weakens the immune system

Infections can’t be fought against

90
Q

Replication of RNA enveloped virus (5 steps)

A
  1. Glycoproteins binds to receptor on host cell
  2. Virus fuses with host cell membrane and capsid is digested
  3. Enzyme reverse transcriptase turns ssRNA into dsDNA in two cycles (RNA to RNA/DNA TO DNA/DNA)
  4. dsDNA incorporated into host genome (provirus)
  5. mRNA is transcribed
    - viral proteins and envelope glycoproteins are produced and transported by vesicles to membrane
    - new viruses are produced and bud from host cell with viral envelope glycoproteins
91
Q

Describe an example of a pathogenic virus

A

H1N1 influenza virus
Single stranded RNA, enveloped
Fatal when spread to lungs

92
Q

Describe an example of a pathogenic fungi

A

Trichophyton spp. (Ringworm)

Colonies spread and immune system responds with inflammation around the edges of the colonies

93
Q

What is a prion?

A

A protein (smallest form of microbe we know of)

94
Q

Example of pathogenic prion

A

Kuru
A misfolded prion which causes degenerative brain disease
Turns normal prions in the brain into pathogenic prions

95
Q

Example of pathogenic Protozoa

A

Plasmodium app. (Malaria parasites)

Invade red blood cells and utilise the hemaglobin

96
Q

Example of pathogenic helminth

A

Ancylostoma (hook worm)

97
Q

Example of pathogenic bacteria

A

Bacillus anthracis
Gram-positive, forms endospores, rod-shaped
Fatal when gets into lungs

98
Q

Kochs postulates (4)

A
  1. Pathogen must be present in every individual with the disease
  2. Sample can be grown in pure culture
  3. Pure culture causes same disease when injected
  4. Microorganism can be recovered from injected host

These demonstrate that a specific pathogen causes specific disease symptoms

99
Q

Four key stages of microbial pathogenesis

A
  1. Adherence to host cells (skin or mucus)
  2. Invasion of host tissues
  3. Replication within host tissues
  4. Disease causing damage to host tissues
100
Q

7 classes of bacterial virulence factors

A

Fimbriae- bind to host cells

Motility- flagella- burrow into tissue

Internalin-related proteins- enzymes to invade tissue

Siderophores- bind iron

Capsules- resist phagocytosis

Endotoxins- cause inflammation

Exotoxins- can be fatal

101
Q

Endotoxins

A

LPS (lipopolysaccharides) components found in membrane of gram-negative bacteria

They are released after the bacterial cell is detected

102
Q

Effects of endotoxins

A

Fever
Inflammation
Blood clotting
Shock

(Strong immune responses)

103
Q

Exotoxins

And their three types

A

Produced within living bacteria, then released into surrounding medium

Cytotoxins
Neurotoxins
Enterotoxins

104
Q

Cytotoxins

A

Type of exotoxin which causes lysis of red blood cells

105
Q

Neurotoxins

A

Type of exotoxins which cause paralysis (prevents release of ACh at NMJ)

106
Q

Enterotoxins

A

Type of exotoxin which effects the gut (like dysentery)

107
Q

Idea of selective toxicity

A

Killing microbial cells but not the human host cells

108
Q

Six bacterial cell components targeted by antibiotic classes

A 
Inhibition of cell wall synthesis
Inhibition of protein synthesis
Disruption of cytoplasmic membrane
Inhibition of general metabolic pathway
Inhibition of DNA/RNA synthesis
Inhibition of pathogens attachment or entry
109
Q

Example of an antibiotic that targets call wall synthesis

How does it work?

A

Penicillin

Inhibits the formation of peptidoglycan cross-links in bacterial cell walls

(It does this by effecting the enzyme that facilitates the amino acid stitching of NAM-NAG)

110
Q

Antibiotic resistance

A

Pathogens develop the ability to defeat the antibiotics designed to kill them

111
Q

How do pathogens develop antibiotic resistance?

A

Natural selection- those with a specific mutation that allow them to survive the antibiotic multiply

112
Q

Name of the enzyme produced by bacteria used to destroy penicillin

A

Beta lactamase

113
Q

Two types of gene transfer

A

Vertical gene transfer- inherited genes from ‘parent’

Horizontal gene transfer- acquired genes from external sources

114
Q

How do we reduce the development of antibiotic resistance? (3)

A

Avoiding antibiotics for viral infections (don’t use them every time you have a cold)

Improving antibiotics to be more specific to certain bacteria

Develop technology to tell if infection is viral or bacterial

115
Q

What is the DNA form in a bacterium?

A

Single circular chromosome

116
Q

Plasmids

A

Small, circular self-replicating molecules of DNA in the cytoskeleton

Separate to main chromosome

117
Q

Three strategies of horizontal gene transfer

A

Transformation
Transduction
Conjugation

118
Q

Describe transformative gene transfer

A

Uptake of short fragments of naked DNA by naturally transformable bacteria

119
Q

Describe transduction gene transfer

A

Bacteriophages transfer DNA (plasmid) from one bacterium to another

120
Q

Describe conjugative gene transfer

A

Transfer of DNA via a sexual pilus physically connecting two bacteria

(DNA has to be unwound before passing through)

CELS (3 decks)

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