Chapter One: The Cell Flashcards
(122 cards)
1
Q
Four Tenents of Cell Theory
A
1) All living things are composed of cells
2) The cell is the basic functional unit of life
3) Cells arise only from preexisting cells
4) Cells carry genetic information in the form of DNA which is passed on from parent to daughter cell
2
Q
Type of organism that are always single-celled
A
Prokaryotic organisms
3
Q
Type of cell that contain a true nucleus enclosed in a membrane
A
Eukaryotic cells
4
Q
Eukaryotic cells reproduce by
A
Mitosis
5
Q
_________ is the double membrane that separates the nuclear environment from the cytoplasm
A
Nuclear membrane or envelope
6
Q
Coding regions of DNA
A
Genes
7
Q
Linear DNA is wound around organizing proteins known as ________, and is then further wound into linear strands called ________
A
Histones; chromosomes
8
Q
Location of DNA within the nucleus allows for compartmentalization of DNA transcription separate from __________
A
RNA translation
9
Q
Nucleolus is the subsection of the nucleus where _______ is synthesized
A
Ribosomal RNA (rRNA)
10
Q
________ is the powerhouse of the cell
A
Mitochondria
11
Q
Purpose of the outer membrane of the mitochondria
A
Barrier between the cytosol and the inner environment of the mitochondrion
12
Q
Inner membrane of the mitochondria is arranged into ________
A
Cristae
13
Q
Purpose of cristae
A
Increase the surface area available for the electron transport chain
14
Q
Space between the inner and outer mitochondrial membranes
A
Intermembrane space
15
Q
The space inside the inner mitochondrial membrane
A
Mitochondrial membrane
16
Q
Why are mitochondria considered semi-autonomous?
A
They contain some of their own genes, replicate independently of the nucleus via binary fission
17
Q
Define cytoplasmic or extranuclear inheritance
A
The transmission of genetic material independent of the nucleus; as is seen in mitochondrial replication
18
Q
Programmed cell death via release of enzymes from the ETC
A
Apoptosis
19
Q
Membrane-bound structures containing hydrologic enzymes that are capable of breaking down different substrates
A
Lysosomes
20
Q
Membrane-bound organelles that package, transport, and sort cell material travelling to and from the membrane
A
Endosomes
21
Q
Organelle capable of transporting materials to the trans golgi, the cell membrane, or the lysosomal pathway for degredation
A
Endosomes
22
Q
Release of lysosomal hydrolytic enzymes that leads to apoptosis
A
Autolysis
23
Q
Series of interconnected membranes that are contiguous with the nuclear envelope
A
Endoplasmic reticulum
24
Q
Primary purpose of the rough ER
A
Translation of proteins destined for secretion directly into the lumen of the ER
25
Three purposes of the smooth ER
1) Lipid synthesis
2) Detoxification of certain drugs and poisons
3) Transporting proteins from the RER to the Golgi apparatus
26
Stacked, membrane bound sacks that receive materials from the ER, modify them, and deliver them to specific cellular locations
Golgi apparatus
27
Secretion of the contents of a vesicles out of the cell
Exocytosis
28
Contents of peroxisomes
Hydrogen peroxide
29
Primary function of peroxisomes
Breakdown of very long chain fatty acids via beta-oxidation
30
Peroxisomes participate in the synthesis of _______ and contain some enzymes involved in the ________ _________ pathway
Phospholipids; pentose phosphate
31
Purpose of the cytoskeleton
Provides support and shape to a cell; provides a conduit for the transport of materials around the cell
32
Three components of the cytoskeleton
1) microfilaments
2) microtubules
3) intermediate filaments
33
Microfilaments are made up of ________
Actin
34
Actin filaments generate force for movement by....
Using ATP and interactions with myosin, like in a muscle contraction
35
Define cytokinesis
The division of materials between daughter cells
36
During mitosis, the cleavage furrow is formed from ___________
Microfilaments
37
________ are hollow polymers of tubulin proteins
Microtubules
38
Microtubules radiate throughout the cell, providing primary pathway along which motor proteins like ____ and ______ carry vesicles
Kinesin and dynein
39
Define cilia
Projections from a cell that are primarily involved in the movement of materials along the surface of the cell - e.g., respiratory tract cilia move mucous
40
Define flagella
Structures involved in the movement of the cell itself - e.g., movement of sperm through the reproductive tract
41
Cilia and flagella share the same structure known as __________ that is composed of ___ pairs of microtubules forming an outer ring, with ____ microtubules in the centre
9+2 structure
42
Centrioles are found in a region of the cell called the
Centrosome
43
Purpose of centrioles
Organizing centres for microtubules
44
Structure of microtubules
Nine triplets with a hollow center
45
During mitosis, the centrioles migrate to opposite poles of the dividing cell and organize the __________
Mitotic spindle
46
During mitosis, the microtubules emanating from the centrioles attach to the chromosomes via complexes called __________ and exert force on the ___________ ___________ to divide them
Kinetochores; sister chromatids
47
Keratin, desmin, vimentin, and lamins are all examples of ____________ __________
Intermediate filaments
48
___________ ___________ are a diverse group of filamentous proteins involved in cell-cell adhesion and maintenance of the overall integrity of the cytoskeleton
Intermediate filaments
49
Four main types of tissues
Epithelial, connective, muscle, and nervous tissue
50
___________ tissues cover the body and line its cavities
Epithelial tissues
51
Purpose of epithelial tissue
Protection against pathogen invasion and dedication
52
Epithelial cells are joined to the __________ __________, an underlying layer of connective tissue
Basement membrane
53
Define parenchyma
The functional part of the organ; separate from the connective and supportive tissues
54
Epithelium with one layer of cells
Simple epithelial
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Epithelium with multiple layers
Stratified epithelia
56
Epithelium that appear to have multiple layers due to differences in cell heights but are actually only one layer
Pseudostratified epithelia
57
Cube-shaped epithelium
Cuboidal cells
58
Long and thin epithelial cells
Columnar cells
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Flat and scale-like epithelial cells
Squamous cells
60
Purpose of connective tissue
Supports the body and provides a framework for the epithelial cells to carry out their functions
61
Connective tissues are the main contributors to the ______
Stroma
62
Define stroma
The support structure of an organ; composed of connective tissue and vasculature
63
_________ cells primarily constitute the parenchyma
Epithelial
64
Most cells in connective tissues produce and secrete materials like collagen and elastin to form the _______ ______
Extra cellular matrix
65
Prokaryotic DNA is organized in ......
A single circular molecule of DNA
66
Prokaryotic DNA is found in the ___________ ___________
Nucleoid region
67
Bacteria are considered what type of organisms?
Prokaryotes
68
Three overarching domains of life (kingdoms)
Archaea, Bacteria, and Eukarya
69
_________ are single celled organisms that are visually similar to bacteria, but contain genes and several metabolic pathways that are more similar to eukaryotes than bacteria
Archaea
70
Define extremophiles
Organisms found in harsh environments with extremely high temperatures, high salinity, or no light
71
Which methods can archaea use to produce energy?
Photosynthesis and chemosynthesis from inorganic compounds like sulfur- and nitrogen-based compounds like ammonia
72
Structures found in all bacteria
Cell membrane, cytoplasm, and some have flagella or fimbriae
73
Define mutualistic symbiotes
Both parties benefit from the relationship; like with humans and bacteria
74
Define pathogen or parasite
Something that provides no advantage or benefit to the host but rather cause disease
75
Three shapes of bacteria
Cocci (spherical)
Bacilli (rod-shaped)
Spirilla (spiralled)
76
Bacteria that require oxygen for metabolism are called:
Obligate aerobes
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Bacteria that use fermentation or other forms of cellular metabolism that don’t require oxygen are called:
Anaerobes
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Anaerobes that cannot survive in an oxygen-containing environment are called:
Obligate anaerobes
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Why can’t obligate anaerobes survive in environments with oxygen?
Presence of oxygen leads to the production of reactive oxygen-containing radicals, which leads to cell death
80
Bacteria that can toggle between aerobic metabolism if oxygen is present, and anaerobic metabolism if it is not, are called:
Facultative anaerobes
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Bacteria that are unable to use oxygen for metabolism, but are not harmed by its presence in the environment
Aerotolerant anaerobes
82
Prokaryotic cells all have which two structures to protect itself from the environment?
Cell wall and cell membrane —> together, they form the envelope
83
Two main types of cell wall in bacteria
Gram positive and gram negative
84
How to determine the type of cell wall of a bacteria?
Gram staining with a crystal violet stain followed by counter staining with safranin; gram-positive bacteria absorb the crystal violet, and gram-negative bacteria only absorb the safranin counterstain which turns them red-pink
85
Gram-positive cell walls consist of a thick layer of:
Peptidoglycans and lipoteichoic acids
86
What are peptidoglycans?
A polymeric substance made from amino acids and sugars
87
Structure of gram-negative bacteria’s cell walls
Thin cell walls which also contain peptidoglycans but in much smaller amounts
Cell walls are adjacent to the cell membrane, separated by the periplasmic space
Outer membranes contain phospholipids and lipopolysacchardies
88
Immune response to lipopolysaccharides verses lipoteichoic acid - which is stronger?
Inflammatory response to lipopolysaccharides is much stronger than the response to lipoteichoic acid
89
Define chemotaxis
The ability of a cell to detect chemical stimuli and move towards or away from them
90
Composition of a flagella
Filament, basal body, and a hook
91
Structure of filaments in flagella
Hollow, helical structure composed of flagellin
92
Structure and purpose of basal body of flagellum
Complex structure that anchors the flagellum to the cytoplasmic membrane and serves as the motor of the flagellum
93
Structure and function of the hook of flagellum
Connects the filament to the basal body so that, as the basal body rotates, it exerts torque on the filament, which thereby spins and propels the bacteria forward
94
DNA acquired from external sources may be carried on smaller circular structures known as _________
Plasmids
95
__________ carry DNA that is not necessary for survival of the prokaryote (therefore not part of the genome) but which may confer advantages like antibiotic resistance
Plasmids
96
Site of ETC and ATP production in prokaryotes
Cell membrane of prokaryotes
97
Define virulence factors
Traits that increase pathogenicity; carried in plasmids in bacteria
98
Define episomes
A subset of plasmids that are capable of integrating into the genome of the bacterium
99
Define transformation re: bacterial genetic recombination
The integration of foreign genetic material into the host genome
100
Define conjugation re: bacterial genetic recombination
Bacterial form of sexual reproduction/mating where plasmids are transcribed and transferred from a donor to a recipient; after wards, this plasmid can be integrated into the genome via transformation
101
Define transformation re: bacterial reproduction
Integration of plasmid into the host genome
102
Define high frequency of recombination or hfr cells
bacterium with a conjugative plasmid integrated into its genome
103
Define transduction re: bacterial genetic recombination
When a virus is used as a vector to carry genetic material from one bacterium to another
104
Define bacteriophage
Viruses that infect bacteria
105
Define transposons re: genetic recombination
Genetic elements capable of inserting and removing themselves from the genome
106
Define virus capsid
The protein coat around the genetic information of a virus
107
Define virons
The viral progeny produced when a virus infects uses a host cell’s ribosomes to replicate its genetic material
108
Define bacteriophages
Viruses that specifically target bacteria
109
How do bacteriophages infect bacteria?
They use their tail fibres to recognize and connect to the correct host cell, then use their tail sheaths to inject genetic material into the host like a syringe
110
What is the structure of a viral genome?
It can be short, long, single- or double-stranded DNA or RNA
111
Define positive-sense RNA viruses
Viruses where the genome can be directly translated to functional proteins by the ribosomes of the host cell, just like mRNA
112
Define negative-sense RNA viruses
Viruses where the RNA strand acts as a template for synthesis of a complementary strand, which can then be used as a template for protein synthesis. Therefore, they must carry an RNA replicas in their virion
113
Define retroviruses
Enveloped, single-stranded RNA viruses that contain two identical RNA molecules and reverse transcriptase to synthesizes DNA from single-stranded RNA —> this means the virions get integrated into the host cells genome
114
Define lytic phase of bacteriophage replication
Bacteriophage maximizes host cell machinery until the host is swollen with new virons, the cell loses, and other bacteria can be infected
115
Define virulent
Viruses in the lytic phase
116
What initiates the lysogenic phase?
If a virus does not lyse the bacterium, it may integrate into the host genome as a provirus or prophage, initiating the lysogenic cycle
117
Define superinfection
Simultaneous infection
118
Define prions
Infectious proteins that cause disease by misfolding of other proteins
119
How do prions function to be infectious?
They trigger misfolding of proteins, usually through conversion of an alpha-helical structure to a beta-pleated sheet. This reduces the solubility of the protein and the ability of the cell to degrade it, causing protein aggregates that interfere with cell function
120
Define viroids
Small pathogens consisting of a very short circular single-stranded RNA that infect plants
121
How do viroids infect plants?
They bind to a large number of RNA sequences and can silence genes in the plant genome
122
Function of the nucleolus
Ribosomal RNA synthesis
