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Biology Flashcards

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1
Q

4 tenets 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. This genetic material can be passed on from parent to daughter cell
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2
Q

Contain a nucleus enclosed in a membrane

A

Eukaryotic cells

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3
Q

Do not contain a nucleus

A

Prokaryotic cells

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4
Q

Organelles of eukaryotic cells

A

Enclosed in semifluid cytosol

Membrane-bound, allowing for compartmentalization of functions

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5
Q

Cytosol

A

Allows for the diffusion of molecules throughout a eukaryotic cell

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6
Q

Nucleus

A

Contains all genetic material necessary for replication
Where genetic material is encoded
Surrounded by nuclear membrane/envelope

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7
Q

Nuclear membrane/envelope

A

Surrounds nucleus
Double membrane that maintains a nuclear environment separate and distinct from the cytoplasm
Contains nuclear pores

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8
Q

Nuclear pores

A

Located in the nuclear membrane/envelope

Allow selective two-way exchange of material between the cytoplasm and nucleus

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9
Q

Nucleolus

A

Located in the nucleus

Synthesizes ribosomal RNA (rRNA)

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10
Q

Mitochondria

A

Important metabolic functions, ATP production, and apoptosis
Contain inner and outer membranes
Contain their own genes and replicate independently of the nucleus via binary fission

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11
Q

Outer membrane of mitochondria

A

Serves as a barrier between the cytosol and the inner environment of the mitochondrion

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12
Q

Inner membrane of mitochondria

A

Arranged into numerous unfolding called cristae

Contains the molecules and enzymes of the electron transport chain

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13
Q

Cristae

A

Highly convoluted structures that increase the surface area available for electron transport chain enzymes

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14
Q

Intermembrane space

A

The space between the inner and outer membranes of the mitochondria

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15
Q

Mitochondrial matrix

A

The space inside the inner membrane of the mitochondria

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16
Q

Apoptosis

A

Programmed cell death due to release of enzymes

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17
Q

Lysosomes

A

Contain hydrolytic enzymes that are capable of breaking down substrates
Function in conjunction with endosomes
Sequesters enzymes to prevent damage to the cell but the enzymes can be released through autolysis which leads to apoptosis

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18
Q

Endosomes

A

Transport, package, and sort cell material traveling to and from the membrane

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19
Q

Endoplasmic reticulum

A

Series of interconnected membranes that are contiguous with the nuclear envelope
Smooth and rough

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20
Q

Rough ER

A

Studded with ribosomes which permit the translation of proteins destined for secretion directly into its lumen

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21
Q

Smooth ER

A

Lacks ribosomes
Utilized primarily for lipid synthesis, detoxification of drugs and poisons, and transportation of proteins from the rough ER to the Golgi apparatus

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22
Q

Golgi apparatus

A

Packages, modifies, and distributes cellular products

Cellular products are modified by adding a group (carbohydrate, sulfate, etc.) or a signal sequence

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23
Q

Peroxisomes

A

Contain hydrogen peroxide
Breakdown very long chains of fatty acids via B-oxidation
Participate in the synthesis of phospholipids and contain the enzymes involved in the pentose phosphate pathway

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24
Q

Cytoskeleton

A

Provides structure to the cell and helps to maintain its shape
Provides a conduit for the transport of materials around the cell
Components: microfilaments, microtubules, and intermediate filaments

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25
Microfilaments
Composed of actin Resistent to fracture and compression which provides protection for the cell Play a role in cytokinesis
26
Cytokinesis
The division of materials between daughter cells Microfilaments create cleavage furrow as a ring at the site of division, as the actin filaments contract, the ring gets smaller and pinches off the connection between the daughter cells
27
Microtubules
Composed of tubulin Provide the primary pathway along which motor proteins carry vesicles Make up cilia and flagella
28
Cilia
Composed of microtubules | Projections from a cell that are primarily involved in the movement of materials along the surface of the cell
29
Eukaryotic flagella
Composed of microtubules | Involved in the movement of the cell itself
30
How do the structures of eukaryotic and prokaryotic flagella differ?
Eukaryotic: 9 pairs of microtubules with 2 microtubules in the center (9+2 structure) Prokaryotic: made of flagellin and consist of a filament, a basal body, and a hook
31
Centrioles
Found in the centrosome The organizing center for microtubules 9 triplets of microtubules with a hollow center
32
Intermediate filaments
Primary protein depends on cel land tissue type but can be keratin, desmin, vimentin, or lamins Involved in cell-cell adhesion or maintenance of the overall integrity of the cytoskeleton Help anchor other organelles
33
Epithelial tissue
Covers the body and lines its cavities Protects against pathogen invasion and desiccation Can be involved in absorption, secretion, and sensation Constitute the parenchyma
34
Parenchyma
The functional tissues of an organ
35
Simple epithelia
Epithelial tissue with one layer of cells
36
Stratified epithelia
Epithelial tissue composed of multiple layers
37
Pseudostratified epithelia
Epithelial tissue that appears to have multiple layers due to differences in cell height but only have one layer
38
Cuboidal cells
Epithelial cells that are cube-shaped
39
Columnar cells
Epithelial cells that are long and thin
40
Squamous cells
Epithelial cells that are flat and scale-like
41
Connective tissue
Supports the body and provides a framework for the epithelial cells to carry out their functions Main contributors to the stroma Produce and secrete materials such as collagen and elastin to form the extracellular matrix
42
Stroma
The support structure of the organ
43
Archea
Single-called prokaryotes Visually similar to bacteria but contain genes and several metabolic pathways that are more similar to eukaryotes Able to use alternative sources of energy
44
Bacteria
Single-called prokaryotes Contain a cell membrane, cytoplasm, and flagella or fimbriae Analogous structure to eukaryotes
45
Mutalistic symbiotes
Bacteria in which both humans and the bacteria benefit from the relationship
46
Pathogens/parasites
Bacteria that provide no advantage or benefit to the host, but rather cause disease
47
Cocci
Spherical bacteria
48
Bacilli
Rod-shaped bacteria
49
Spirilli
Spiral-shaped bacteria
50
Obligate aerobes
Bacteria that requires oxygen for metabolism
51
Anaerobes
Bacteria that use fermentation or some other form of cellular metabolism that does not require oxygen
52
Obligate anaerobes
Bacteria that cannot survive in an oxygen-containing environment
53
Facultative anaerobes
Bacteria that use oxygen for aerobic metabolism when it is present and use anaerobic metabolism when it is not
54
Aerotolerant anaerobes
Bacteria that are unable to use oxygen for metabolism but are not harmed but its presence in the environment
55
Prokaryotic cell structure
Lack a nucleus and membrane-bound organelles | Single-celled
56
Cell wall
Forms outer barrier of the cell Provides structure send controls the movement of solutes into and out of the bacterium Gram-positive and gram-negative
57
Cell (plasma) membrane
Composed of phospholipids
58
Gram-positive cell wall
Thick layer of peptidoglycan, a polymeric substance made from amino acids and sugars Provides protection from a host organism’s immune system Also contains lipoteichoic acid
59
Gram-negative cell wall
Thin layer of peptidoglycan which is separated from the membrane by the periplasmic space Outer membrane contains phospholipids and lipopolysaccharides Lipopolysaccharides trigger an immune response in human beings much stronger than the response to lipoteichoic acid
60
Prokaryotic flagella
Whip-like structures used for propulsion Used to move toward food or away from toxins and immune cells Composed of a filament, a basal body, and a hook
61
Chemotaxis
The ability of a cell to detect chemical stimuli and move toward or away from them
62
Plasmids
Carry DNA that is not necessary for the prokaryote’s survival This DNA may confer some advantage even though it is not a part of the bacterium’s genome Carry virulence factors
63
Binary fission
A simple form of asexual prokaryotes | Proceeds more rapidly than mitosis
64
Virulence factors
Traits that increase pathogenicity | Carried by plasmids
65
Episomes
A subset of plasmids | Capable of integrating into the genome of the bacterium
66
3 mechanisms of genetic recombination
1. Transformation 2. Conjugation 3. Transduction
67
Transformation
Results from the integration of foreign genetic material into the host genome Gram-negative rods carry out this process
68
Conjugation
Bacterial form of mating | Involves two cells forming a conjugation bridge that facilitates the transfer of genetic material
69
Conjugation bridge
Facilities the transfer of genetic material from the donor male to the recipient female
70
F+ cells vs. F- cells
F+ cells posses the F (fertility) factor plasmid | F- cells do not posses this sex factor plasmid
71
High frequency of recombination cells
Hfr The sex factor is a plasmid but, through transformation, can become integrated into the host genome. When conjugation occurs, the entire genome replicates and the donor cell will attempt to transfer an entire copy of its genome into the recipient. The conjugation bridge breaks before the whole DNA sequence is moved.
72
Transduction
The only genetic recombination process that requires a vector Bacteriophages incorporate a segment of host DNA during assembly. Transferred DNA integrates into the genome and gives the new host additional genes.
73
Vector
A virus that carries genetic material from one bacterium to another
74
Bacteriophages
Viruses that infect bacteria Do not enter bacteria, but inject their genetic material Composed of a capsid, a tail sheath, and tail fibers
75
Transposons
Genetic elements capable of inserting and removing themselves from the genome
76
4 phases of bacterial growth
1. Lag phase 2. Exponential/ log phase 3. Stationary phase 4. Death phase
77
Lag Phase of bacterial growth
Bacteria adapt to the new, local conditions of their environment
78
Exponential/log phase of bacterial growth
As bacteria adapt, the rate of division increases
79
Stationary phase of bacterial growth
As the number of bacteria grows, resources are reduced which slows reproduction
80
Death phase of bacterial growth
Bacteria have exceeded the ability of the environment to support the number of bacteria Depletion of resources
81
Capsid
The protein coat that is one part of what viruses are composed of Surrounded by an envelope made of phospholipids and virus-specific proteins
82
Virions
The viral progeny that viruses produce after replicating | Can be released to infect additional cells
83
Tail sheath
One part of bacteriophages | Acts like a syringe to inject genetic material into the bacterium
84
Tail fibers
One part of bacteriophages | Help the bacteriophages recognize and connect to the correct host cell
85
Positive sense RNA viruses
The genome may be directly translated to functional proteins by the ribosomes of the host cell
86
Negative sense RNA viruses
RNA strand acts as a template for synthesis of the complementary strand which can then be used as a template for protein synthesis Carry an RNA replicase in the virion
87
RNA replicase
Carried by negative sense RNA viruses | Ensures that the complementary strand is synthesized
88
Retroviruses
Enveloped, single-stranded RNA viruses | Carry reverse transcriptase
89
Reverse transcriptase
Carried by retroviruses | Synthesizes DNA from single-stranded RNA
90
Types of progeny release
1. Viral invasion may initiate cell death resulting in the spillage of viral progeny 2. Host cell may lyse as a result of being filled with extremely large numbers of virions 3. Extrusion
91
Extrusion
Virus leases the cell by fusing with its plasma membrane | This process keeps the host cell alive and allows the virus to continue using it (productive cycle)
92
Lytic cycle
Bacteriophages maximize the use of the cell’s machinery with little regard for the survival of the host cell. Once the host cell is swollen with new virions, the cell lyses, and other bacteria can be infected
93
Virulent
Viruses in the lytic phase
94
Lysogenic cycle
The virus is replicated as the bacterium reproduces because it is a part of the host’s genome
95
Provirus/prophage
Viruses in the lysogenic phase
96
Prions
Infectious proteins Nonliving Cause disease by triggering misfolding of other proteins, usually from an a-helical structure to a B-pleated sheet
97
Viroids
Small pathogens consisting of a very short circular single-stranded RNA that infect plants Bind to a large number of RNA sequences and can silence genes, preventing the synthesis of necessary proteins
98
Why are viruses considered obligate intracellular parasites?
Viruses do not contain organelles such as ribosomes. Therefore, in order to reproduce and synthesis proteins, viruses ist infect cells and hijack their cellular machinery

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