The Cell Flashcards
1
Q
What are the 4 tenants of cell theory?
A
1, All living things are made of cells.
2. The cell is the basic unit of life.
3. Cells only arise from pre-existing cells.
4. All cells use DNA as their heritable material.
2
Q
What is the primary purpose of the nucleus?
A
contain all necessary genetic information for eukaryotic organisms
3
Q
How is the genetic material of eukaryotic organisms organized?
A
Chromosomes
4
Q
What purpose do nuclear pores serve?
A
Selective permeability
5
Q
What are genes?
A
The coding region of DNA
6
Q
What are histones?
A
The proteins around which DNA is organized
7
Q
Where in the cell will you find DNA?
A
Only in the nucleus
8
Q
Why is DNA compartmentalized?
A
To prevent DNA transcriptase and RNA translation from interacting
9
Q
What is the nucleolus?
A
Subsection of nucleus where rRNA is synthesized
10
Q
How much of the nucleus does the nucleolus comprise?
A
About 25%
11
Q
How can you identify the nucleolus under a microscope?
A
It is the dark spot in the nucleus
12
Q
What is rRNA?
A
ribosomal RNA
13
Q
How many membranes does the mitochondria have?
A
2
14
Q
What are cristae?
A
The inner membrane of the mitochondria
15
Q
What is the function of cristae?
A
To hold enzymes and to create an Electron Transport Chain (ETC) in order to produce energy
16
Q
How do cristae create an Electron Transport Chain?
A
They are highly folded in order to increase surface area
17
Q
What is the space between the mitochondrial inner and outer membranes called?
A
The inter membrane space
18
Q
What is the space inside of the cristae called?
A
The matrix
19
Q
What drives ATP synthase?
A
a Proton Motive Force (PMF)
20
Q
What creates the PMF in mitochondria?
A
The pumping of H+ ions from the matrix through the ETC to the inter membrane space
21
Q
When is the PMF created in mitochondria?
A
During oxidative phosphorylation
22
Q
How do mitochondria replicate?
A
Binary fission
23
Q
The replication of mitochondria is an example of what?
A
cytoplasmic or extranuclear inheritance
24
Q
Why are the mitochondrial enzymes separated from the cytoplasm?
A
They are highly toxic, and upon release trigger apoptosis
25
What is the primary function of lysosomes?
Degrade waste and pathogens
26
How do lysosomes perform their function?
Via the use of hydrolytic enzymes
27
Why must lysosomal enzymes be separated from the cytoplasm?
They are highly toxic and trigger autolysis
28
What does autolysis trigger?
Apoptosis
29
What are the two kinds of endoplasmic reticulum?
Smooth and rough ER
30
How can you differentiate between smooth and rough ER?
Smooth ER lacks ribosomes, whereas the Rough ER is studded with many ribosomes
31
What is the primary function of the smooth ER?
To synthesize lipids and detoxify some drugs and poisons
32
What is the primary function of the Rough ER?
To translate proteins which are secreted directly into the lumen of the RER
33
What is the primary function of the Golgi apparatus?
To modify and repackage cellular products
34
How can the Golgi modify cellular package?
Addition of carbohydrates, phosphates, sulfates, signal sequences, and more to cellular products
35
After modification in the Golgi, what happens to cellular products?
They are packaged in vesicles and sent to their final destination
36
How are cellular products transported to the Golgi from the ER?
Vesicles
37
Which ER sends products to the Golgi?
the RER
38
What do peroxisomes do?
Breakdown Long Chain Fatty Acids
39
How do peroxisomes perform their primary function?
Beta-oxidation
40
What do peroxisomes contain?
Hydrogen peroxide (H2O2)
41
What process do peroxisomes participate in?
Lipid synthesis
42
What pathway are peroxisomes important to and why?
The pentose phosphate pathway, they contain vital enzymes
43
What are the 3 components of the cytoskeleton?
Microfilaments, Microtubules, and Intermediate Filaments
44
What are microfilaments composed of?
Actin polymers
45
What is the primary function of microfilaments?
To protect the cell via resisting compression and fracture
46
What can microtubules interact with and in which process?
Myosin, and in movement via use of ATP
47
What key process are microfilaments involved in?
Mitosis, via formation of the cleavage furrow
48
What is the cleavage furrow?
the ring of microtubules (actin) which slowly pinches two daughter cells apart during mitosis
49
What are microtubules comprised of?
Tubulin proteins
50
Are microtubules hollow?
Yes
51
How are microtubules arranged in the cell?
They radiate out from the center to provide pathways for motor proteins
52
What is the function of motor proteins?
To carry vesicles
53
What comprises cilia and flagella?
Microtubules
54
What is the 9+2 rule?
Every cilia and flagella is composed of 2 rings of microtubules. The outer ring is comprised of 9 pairs of microtubules, and the inner ring is comprised of 2 pairs.
55
Which organisms is the 9+2 rule seen in?
Eukaryotes only
56
What are cilia?
Hairlike projections from cells which aid in movement of materials along the cell
57
Where in the body would you find cilia?
The intestine, any mucous membrane, etc.
58
What is the primary function of flagella?
Cellular movement
59
Where are centrioles found?
Centrisome
60
What is the role of a centriole?
It is an organizing center for microtubules
61
What structure format does a centriole take?
9 triplets of microtubules forming a hollow ring
62
What cellular process are centrioles involved in?
Mitosis
63
How are centrioles involved in mitosis?
They migrate to polar ends of the cell and then extend microtubules to the center of the cell to bind with the chromosomes in order to aid in the separating of chromosomes.
64
What is a kinetochore?
The microtubules-chromosome complex
65
What are the functions of intermediate filaments?
Cell:cell adhesion, maintenance of overall cytoskeleton via increase in rigidity of cell, anchor organelles
66
What are examples of intermediate filaments?
Keratin, desmin, vimentin, lamis
67
What comprise intermediate filaments?
Filamentous proteins
68
What are the 4 tissue types?
1. Epithelial
2. Nervous
3. Muscular
4. Connective
69
What is the function of epithelial tissue?
To protect against pathogen invasion and desiccation by covering body and lining cavities, as well as playing a role in absorption, secretion, and sensation.
70
How are epithelial cells arranged?
They are joined together and to a connective tissue layer
71
What is the basement membrane?
The layer of connective tissue which anchors epithelial cells
72
Define parenchyma
The functional cells of an organ
73
Are epithelial cells usually in the parenchyma or the stroma?
The parenchyma
74
Epithelial cells are often polarized- why?
Epithelial cells are often the linings of tubes or cavities, meaning they need to have one side which is anchored and structured (the basal layer) and one which is facing "inwards" in order to be mucousal, abrasive, absorptive, secretive, or serve other functionalities. The basal surface provides a designated area for blood vessel, hair follicle, and neural integration, whereas the apical surface allows for highly specialized functionality to occur.
75
How are epithelial cells classified?
According to both size and shape
76
What categories are there for epithelial cell shapes?
Cuboidal, squamous, and columnar
77
What categories are there for an epithelial cell's size?
Simple, stratified, and pseudostratified
78
Define simple epithelial cells.
Epithelial cells with one single layer.
79
Define pseudostratified epithelial cells.
Epithelial cells which appear to be multiple layers, but are actually only one layer.
80
Define stratified epithelial cells.
Epithelial cells which occur in layers of multiple cells.
81
Define the squamous cell shape
Scaley and flat
82
Define the columnar cell shape
Taller than wide, often with cilia or protrusion
83
Define cuboidal cell shape
Square shaped
84
What is the primary function for connective tissue?
To provide support and framework for the body's cells
85
Is connective tissue part of the stroma or parenchyma?
Stroma- it is a collection of support cells
86
How is connective tissue supportive?
It provides framework as well as producing and secreting things like collagen and elastin which form the extracellular matrix
87
What is a prokaryote?
The simplest life form, they are single celled life forms without membrane bound organelles.
88
Where is prokaryotic DNA found and in what form?
In the nucleoid region, and in a circular form.
89
What are the 3 domains of life?
Eukaryea, Prokarea, Archaea
90
Define Archaea
Visually similar to bacteria, these life forms are more functionally similar to eukaryotes. They often use alternative sources of energy and most likely have a common ancestor with eukarya.
91
What are extremophiles?
Organisms (almost exclusively archaea) which are found at extreme temperatures, salinity levels, or in the absence or prescence of odd metabolites.
92
What evidence is there that archaea are more closely related to eukarya than bacteria?
They both start translation with methionine, they both wrap their DNA around histones, and they have similar RNA polymerases,
93
What forms of alternative energy sources can archaea use?
Many are photosynthetic, can be chemosynthetic from inorganic molecules like nitrogen and sulfur
94
What 2 things do all bacteria have?
Cell membranes and cytoplasm
95
What is a term for bacterial flagella?
Fimbrae
96
What essential nutrients do bacteria in the human gut provide?
Vitamin K and biotin
97
What vitamin is biotin?
B7
98
Why is vitamin K necessary for human life?
It is necessary for plasma proteins which assist with blood clotting
99
What are common bacterial drug targets?
Cell wall, cell membrane, LPS, ribosomes, fimbrae/flagella
100
What are cocci?
Spherical bacteria
101
What are bacilli?
rod-shaped bacteria
102
What are spirilli?
Spiral-shaped bacteria
103
What are obligate anaerobes?
Bacteria which require no oxygen in order for survival- they are killed by oxygen
104
What are facultative aerobes?
Bacteria which can use oxygen for their metabolism in its presence but which do not require it
105
What are aerotolerant aerobes?
Bacteria which are not killed by the presence of oxygen, but which do not have a metabolic necessity for it
106
What are obligate aerobes?
Bacteria which require oxygen for their metabolism and which will die without it
107
What structure must all prokaryotes have?
Cell walls
108
What is the function of a prokaryotic cell wall?
To provide structure and the outer barrier of a cell, as well as the control of solutes in and out of the cell. It helps to avoid desiccation and detection by the host immune system.
109
What is the next layer inward from the cell wall of a prokaryote?
Cell membrane
110
What 2 layers form the envelope of a prokaryote?
Cell wall and cell membrane
111
What color is a Gram+ cell under a microscope (with proper staining)
Purple
112
What positive stain is used in Gram staining?
Crystal violet
113
What counter stain is used in Gram staining?
Safranin
114
What color is a Gram- bacteria under a microscope? (with proper staining)
pink/red
115
Describe a Gram+ bacteria
Thick layer of peptidoglycan which contains lipoteichoic acid.
116
What is the function of lipoteichoic acid?
Function unknown, may assist in activation of host immune system
117
Describe a Gram - bacteria's cell wall.
Thin layer of peptidoglycan which directly contacts the cell membrane.
118
What do the outer membranes of Gram - bacteria contain?
Lipopolysaccharides (LPS)
119
What does LPS do?
Strongly activates human immune system
120
Which is a stronger immune activator- LPS or Lipotechoic acid?
LPS
121
What is the function of bacterial flagella?
to allow for propulsion and movement
122
Define chemotaxis
The movement towards/away from food/toxins
123
What are the 3 regions of bacterial flagella?
Filament, hook, basal body
124
Describe the bacterial flagella's filament
Hollow tube made of flagellin
125
Describe the bacterial flagella's basal body
Anchor of flagellum into cell membrane, contains motor proteins
126
What is the max frequency of bacterial flagella?
300 hz
127
Describe bacterial flagella's hook.
Connects filament to basal body, translates torque generated by basal body filaments.
128
What are plasmids?
Extrachromosomal genetic information in circular form. Often acquired from the environment, these can include beneficial attributes such as antibiotic resistance and virulence factors.
129
Are plasmids considered part of the genome?
No, because they normally do not integrate.
130
Since prokaryotes lack mitochondria, how do they generate ATP?
Use cell membranes to generate ETC and PMF.
131
What subunits are found in eukaryotic ribosomes?
40S and 60S
132
What ribosomal subunits are found in prokaryotes?
30S and 50S
133
How do prokaryotes reproduce?
Binary fission
134
Define binary fission.
The simplest form of asexual reproduction.
135
Describe the steps to binary fission
1. Attachment of circular chromosome to cell wall. Replication begins. Cell grows rapidly.
2. Cell walls and membranes begin to invaginate and divide into 2 daughter cells. Replicated DNA separates into each cell.
3. Cells separate, 2 daughter cells finished forming.
136
How can genetic recombination take place in prokaryotes?
Transformation, conjugation, transduction
137
What are episomes?
Plasmids capable of integrating into host genome
138
What are virulence factors?
Factors which increase a pathogen's pathogenicity. These can be toxin production, attachment mechanisms, immunoevasion tactics, or more.
139
What is transformation?
The uptake of environmental genetic information
140
What is conjugation?
Bacterial sexual reproduction
141
Describe the steps of bacterial conjugation
1. Formation of conjugation bridge.
2. Physical contact between donor and recipient cells.
3. Transfer of F-plasmid.
4. Synthesis of complementary strand in both donor and recipient.
5. Separation of cells.
142
What is the F factor?
Fertility factor, the most well studied conjugation factor in bacteria. Originally found in E. coli.
143
Can any bacteria form sex pili?
No, it must have the sex factors.
144
What are sex factors?
Genes which allow for the formation of the sex pili, on plasmids.
145
What kinds of genes can be acquired through conjugation?
Almost any- frequently antibiotic resistant genes are conferred.
146
What are Hfr cells?
High frequency of recombination cells. These are cells which have sex factors integrated into their genome, and therefore transfer whole genome during conjugation. This "whole genome" will often break during transfer, leading to high frequency recombination.
147
What is transduction?
Gene transfer requiring a vector- often a virus
148
What is a bacteriophage?
A virus which infects bacteria
149
How can bacteriophages lead to transduction?
Bacteriophages can release host DNA into new host when infecting new host's genome, which can then integrate into hew host genome.
150
What are transposons?
"jumping genes", these are genetic elements which can insert and excise themselves from genomes seemingly at will
151
What kinds of organisms are transposons found in?
All
152
Can transposons have negative effects?
Yes, can disrupt a gene if they "jump" into a coding region
153
Name the bacterial growth phases.
Lag, log, stationary, death.
154
What is the lag phase of bacterial growth?
The phase after bacteria are initiated into a new climate, wherein they are adjusting to the new environmental conditions and the death and growth rate are roughly the same.
155
What is the log phase of bacterial growth?
The phase following the lag phase, wherein bacteria have adjusted to their new environmental conditions and their populations boom, replicating much quicker than they died off. This utilizes nutrients quickly and leads to the next phase.
156
What is the stationary phase of bacterial growth?
The phase immediately following the log phase wherein the bacteria have utilized most of the nutrients, and the population is stabilizing.
157
What is the death phase of the bacterial growth cycle?
The phase in which nearly all nutrients have been utilized and the reproduction rate plummets while the death rate sky rockets.
158
What are viruses?
Non living organisms which are obligate intracellular parasites. They have their own genetic material, but no machinery to exercise the replication or translation of it, as well as no way to make their own energy.
159
What are the 3 components of viral structure?
The genetic material, protein coat, and envelope (sometimes)
160
What form is viral genetic information in?
Can be circular or linear, DNA or RNA based
161
What is a viral capsid?
Viral protein coat
162
Where will the viral envelope go
Outside of the viral capsid.
163
Does the viral envelope aid in protection from host immune system?
No, it is sensitive to immune attack, detergents, and desiccation, often making the virus easier to kill.
164
What kinds of viruses are resistant to sterilization?
Nonenveloped viruses, as they are often resistant to high heat and can live on surfaces for longer.
165
What are virions?
Viral progeny
166
What are bacteriophage tail sheaths?
They act as the syringe for genetic info injection
167
What function do bacterial tail fibers serve?
They help in the virus' bacterial recognition and adhesion, and can even drill pores in the cell wall.
168
Describe negative sense single stranded RNA viruses
Viruses which contain information requiring RNA replicase to synthesize a complementary RNA strand before translation can occur.
169
Describe positive sense single stranded RNA viruses
Viruses which have genetic information in the form of RNA which can be read by host machinery without further work, acts similarly to mRNA
170
What are retroviruses?
Enveloped SSRNA viruses from family REtroviridae.
171
How many copies of the genetic information do retroviruses carry?
2 identical copies of the RNA
172
What is reverse transcriptase and which viruses carry it?
Retroviruses carry reverse transcriptase in order to allow the synthesis of DNA from SSRNA. This DNA then integrates into host genome and is replicated and translated, allowing for indefinite infection.
173
Name the steps of the viral life cycle
Infection, Translation and Protein assembly, Progeny Release
174
Describe Infection in terms of the viral life cycle
Infection requires binding of specific host receptors, and then viral fusion to cell membrane in order to release virions. If the host cell interprets the virus as nutrients, it may bring the virus directly in via endocytosis. Otherwise, tail fibers and sheaths work together to inject the virions.
175
What must occur in the translation and progeny assembly phase of the viral life cycle?
First, translation of genetic material must occur. (If DNA virus, this requires transport to nucleus so that mRNA can be made)
+ sense RNA viruses are translated directly in cytoplasm, - sense RNA viruses are translated in cytoplasm post complementary strand synthesis by RNA transcriptase.
Viruses also use host machinery to build their capsids and replicate their genome, before assembling in the cytoplasm.
