Prokaryotic Cell Structures - Chapter 2 Flashcards
(152 cards)
1
Q
What are the components of every prokaryotic cell?
A
DNA, membranes, ribosomes, and cytoplasm
2
Q
What are the components of the cell true in?
A
Bacteria, archaea, fungi, algae, protozoa, and helminths
3
Q
What are the components of the cell not true in?
A
Viruses as they can lack a plasma membrane, ribosomes, or DNA
4
Q
What is the component of the cell that viruses have?
A
Cytoplasm as they will take some of the host cell’s cytoplasm
5
Q
What is not in prokaryotes that are in eukaryotes?
A
Membrane-bound organelles such as the nucleus
6
Q
Why are viruses not considered cells?
A
They can’t independently translate proteins, they exclusively rely on a host cell
7
Q
What does a nucleoid contain?
A
Chromosomes and nuclear-associated proteins
8
Q
What can you look for to find the nucleoid?
A
DNA
9
Q
What are chromosomes usually in prokaryotes?
A
Haploid and circular
10
Q
Haploid
A
One copy of the chromosome
11
Q
What are chromosomes usually in eukaryotes?
A
Diploid and linear
12
Q
How many chromosomes are in humans
A
23 unique chromosomes or 24 unique chromosomes in males (1 X, 1Y)
13
Q
What is the nucleoid NOT?
A
It is not a nucleus or membrane-bound
14
Q
What can plasmid also be referred to as?
A
Bonus DNA
15
Q
What is the plasmid?
A
Circular double-stranded DNA
16
Q
What is the size comparison between chromosomes and plasmid?
A
They are much smaller than bacterial chromosomes
17
Q
Where is the plasmid located?
A
Throughout the cytoplasm
18
Q
How many plasmids can you have?
A
1-100s, you can have multiple unique plasmids and multiple of the same plasmids
19
Q
What do plasmids encode for?
A
Antibiotic resistance genes and virulence factors
20
Q
Virulence factors
A
Different things that help bacteria infect us better
21
Q
Is plasmid a part of the chromosome?
A
No
22
Q
What does the ribosome do?
A
Protein synthesis
23
Q
What is the ribosome made up of?
A
Proteins and RNA
24
Q
What are the parts of a ribosome?
A
The large and small subunit
25
What is the size of the small subunit in prokaryotes?
30S
26
What is the size of the large subunit in prokaryotes?
50S
27
What is the total size of the ribosome in prokaryotes?
70S
28
What is the size of the small subunit in eukaryotes?
40S
29
What is the size of the large subunit in eukaryotes?
60S
30
What is the total size of the ribosome in eukaryotes?
80S
31
What is used to sequence in prokaryotes?
16S rRNA
32
What is used to sequence in eukaryotes?
18S rRNA
33
What does S stand for in the unit of the subunit?
Svenbergs
34
What do both prokaryotic and eukaryotic ribosomes have in common?
They both use mRNA to make proteins and are composed of proteins and RNA
35
What is the difference between prokaryotic and eukaryotic ribosomes?
-The size of the subunits (Prokaryotic - 30S, 50S, 70S Eukaryotic - 40S, 60S, 80S)
-What's used for sequencing (Prokaryotic - 16S, Eukaryotic - 18S)
-The position (Prokaryotic - free-floating, Eukaryotic - free-floating or attached to the ER membrane)
36
Are inclusions in all bacteria?
No, they are not
37
Inclusions
Storage of nutrients, etc., similar to vesicles as we move things around in them, protein coat (shell) instead of lipid
38
Why do we have inclusions?
There are no membrane-bound organelles
39
What are the types of inclusions?
Lipid droplets, volutin, sulfur inclusions, gas bubbles, and magnetosomes
40
Lipid Droplets
Lipid storage
41
Volutin
Storage of inorganic phosphates, inclusion
42
Why do we want phosphates?
To make ATP for respiration
43
Sulfur Inclusions
Storage of sulfur, electron acceptor if there is no oxygen
44
What are sulfur inclusions used for?
Metabolism
45
Gas Bubbles
Inclusion that controls buoyancy
46
What are gas bubbles equivalent to?
Swim bladder
47
What are gas bubbles found in?
Aquatic bacteria as it helps them move
48
Magnetosomes
Bacteria that are magnetic, aid in movement as they can move towards or away from a pole
49
What do magnetosomes contain?
Magnetic metals such as iron oxide or iron sulfide
50
Are endospores in every bacteria?
No, they are not
51
Where are endospores found?
Inside the bacteria
52
Endospore Function
Protect bacteria in a dormant state from dying
53
What genera produce endospores?
Bacillus and Clostridia
54
How do endospores form?
The bacteria are lysed open, the bacteria technically die in this process
55
Sporulation
Process of becoming dormant/making endospores
56
Germination
Process of becoming active, happens in nutrient-rich and moist environments
57
When does sporulation occur?
When the bacteria are in a nutrient-poor or dry environment
58
Sporulation Steps
DNA replication, membranes form around the DNA, forespore forms additional membranes, protective cortex forms around the spore, protein coat forms around the cortex, spore is released
59
Cortex
The first protein coat
60
What does the protein coat around the cortex do?
It locks in moisture so that osmosis doesn't occur
61
What is a characteristic of the plasma membrane?
Semi-permeable
62
Plasma Membrane Composition
Composed of lipids and proteins
63
Plasma Membrane Function
It controls transport into and out of the cell
64
What are the kinds of membrane transport?
Diffusion, facilitated diffusion, active transport, and endocytosis
65
Glycoproteins
Have sticky carbohydrates to interact with different surfaces
66
Endocytosis
Only in eukaryotes, invaginates things into the membrane
67
What does endocytosis need to occur?
A vesicle, a membrane-bound organelle, which bacteria lack
68
Sterols
Cholesterol or ergosterol
69
What are sterols unique to?
Eukaryotes
70
What is cholesterol found in?
Humans
71
What is ergosterol found in?
Fungi
72
Diffusion
Used in bacteria, high to low concentrations
73
Simple Diffusion
Move from areas of high to low concentrations without any help
74
Facilitated Diffusion
Move from areas of high to low concentrations, normally large molecules are transported this way as they can't pass through the membrane and need the help of a protein channel
75
Active Transport
Move from areas of low to high concentrations, requires energy as it's moving against the gradient
76
Cell Wall Function
Creates a rigid structure that protects the cell from harsh environments
77
What does the cell wall contain in bacteria?
Peptidoglycan
78
What are the types of bacteria?
Gram-negative and gram-positive
79
What does the cell wall contain in plants?
Cellulose
80
Periplasmic Space/Periplasm
Space between the cell wall and the plasma membrane
81
Gram-Positive Bacteria
Thick cell wall -> more protective, but also more vulnerable to temperature changes, detergents, and soaps
82
What do gram-positive bacteria have?
Teichoic acid and lipoteichoic acid
83
Gram-Negative Bacteria
Thin cell wall and an outer membrane
84
Outer Membrane
A bonus membrane that is more permeable to different types of molecules compared to the plasma membrane, contains special glycolipids
85
What do gram-negative bacteria have?
LPS which is the lipid part embedded in the outer leaflet of the outer membrane
86
Mycoplasma sp
Lack a cell wall so to determine the category it has to go through 16S sequencing
87
Peptidoglycan Types
N-acetylglucosamine (NAG), N-acetylmuramic acid (NAM), and tetrapeptide
88
What peptide is only in gram-positive bacteria?
Pentapeptide
89
Tetrapeptide
Link peptides
90
Pentapeptides
Help stack top to bottom to get a thicker peptidoglycan, gram-positive
91
How do gram-negative bacteria connect their peptides?
Through horizontal connections to get a thinner peptidoglycan
92
Lipopolysaccharide (LPS)
Structural component of the outer membrane, a toxin that over-activates the immune response, gram-negative bacteria
93
What part of LPS is toxic?
The lipid portion
94
Are the majority of the gut bacteria gram-positive or gram-negative?
Gram-negative
95
When does LPS have a toxic effect?
It is embedded in the membrane so it has to come out of the membrane to have a toxic effect
96
What removes LPS from the membrane?
Enzymes such as antibiotics, disruption by soaps, or cell division
97
What projects off the surface of the cell?
Carbohydrates are on the outer membrane, O antigen, and core
98
Where are lipids embedded?
Lipids are embedded in the outer leaflet of the outer membrane closer to the fatty acid side
99
Gram Stain Process
Crystal violet, iodine, alcohol, and safranin
100
Crystal Violet Stain
Primary stain added to the specimen smear
101
What effect does crystal violet stain have on cells?
It stains both gram-positive and gram-negative cells purple or blue
102
Iodine Stain
Mordant makes dye less soluble so it adheres to cell walls, helps dye stick better
103
What effect does iodine have on cells?
Cells remain purple or blue
104
Alcohol Stain
Decolorizer/destainer washes away stains from gram-negative cell walls
105
What effect does alcohol have on cells?
Gram-positive cells remain purple or blue. Gram-negative cells are colorless.
106
Safranin Stain
Counterstain/secondary stain which allows dye to adhere to gram-negative cells
107
What effect does safranin have on cells?
Gram-positive cells remain purple or blue. Gram-negative cells appear pink or red.
108
Are acid-fast bacteria gram-negative or gram-positive?
Gram-positive as it has a plasma membrane and layer of peptidoglycan
109
What happens when acid-fast bacteria stain?
It won't stain gram-positive as it has an extra layer called mycolic acid
110
Mycolic Acid
Waxy substance which prevents gram stain dyes to penetrate
111
Acid Fast Stain
Dyes mycolic acid red as it's specific to mycobacterium s.p.
112
Mycobacterium s.p.
Bacteria causing TB and leprosy
113
Glycocalyces
Capsule or slime layer
114
What do glycocalyces help in?
Help bacteria stick to surfaces and aid in biofilm formation
115
Biofilm
Communities of bacteria living together
116
What is the s-layer commonly found in?
Archaea
117
S-Layer
Substitute cell wall
118
Fimbriae
Short bristle-like protein projections off the cell, coat the bacteria
119
Fimbriae Function
Help bacteria adhere to surfaces
120
Pili
Medium-length protein projections, less numerous
121
Pili Function
Help bacteria adhere to surfaces and aid in DNA transfer -> specifically plasmid DNA (conjugation)
122
Flagellum
Longest protein projections
123
Flagellum Function
Aid in movement
124
What are flagellum made of?
The protein flagellin which are eukaryotic flagella made of actin and microtubules
125
Types of Flagella
Monotrichous, amphitrichous, lophotrichous, peritrichous
126
Monotrichous
One flagella
127
Amphitrichous
One flagella at each end, two together
128
Lophotrichous
Several flagella at the same end
129
Peritrichous
Lots of flagella are found everywhere
130
What do gram-positive bacteria have to pass through?
Peptidoglycan and the inner membrane
131
What do gram-negative bacteria have to pass through?
2 membranes with peptidoglycan in the middle
132
What are flagella and cilia made up of?
Actin and tubulin
133
What do flagella and cilia form?
Bundles that project out of the cell
134
What are cilia similar to?
Fimbriae
135
Where are cilia not found?
Not found in prokaryotes
136
How do bacteria move?
Tumbling or running of flagella (like a motor to propel them forward)
137
Tumbling of Bacteria
Clockwise rotation of flagella, causes flagella to splay which will slow down, turn it, or stop it
138
Running of Bacteria
Counter-clockwise rotation of flagella, flagella bundle together, bacteria move forward
139
What do bacteria follow when moving?
Nutrients or other signals
140
Chemotaxis
Moving toward or away from a chemical
141
Bacteria Shapes
Coccus, bacillus, vibrio, coccobacillus, spirillum, and spirochete
142
Coccus Shape
Round
143
Bacillus Shape
Rod-shaped
144
Vibrio Shape
Curved rods
145
Coccobacillus Shape
Short rod, ovalish shape
146
Spirillum Shape
Wave-shape
147
Spirochete Shape
Coil
148
Diplococcus
Pair of 2 cocci
149
Tetrad
Grouping of 4 cells arranged in a square
150
Streptococcus
Chain of cocci
151
Staphylococcus
Cluster of cocci
152
Streptobacillus
Chain of rods
