Biology Ch. 1: The Cell Flashcards
Num cells in body
37 trillion
Ratio of bacterial to eukaryotic cells
10 to 1
Cell Theory
- All living things are composed of cells
- The cell is the basic functional unit of life
- Cells arise only from preexisting cells
- Cells carry genetic information in the form of DNA, which is passed from parent to daughter cell
Viruses and cell theory
No alive because can only replicate by invading other organisms and genetic material is RNA
Eukaryotic reproduction
Mitosis - two identical daughter cells
Cytosol
Semifluid within cell, allows for diffusion of molecules throughout cell, suspends organelles
Membranes of eukaryotic cells
Both cell membrane and organelle membranes contain phospholipids with hydrophilic interior and exterior and hydrophobic core
Eukaryotic cells
Have membrane bound organelles, a nucleus, and may form multi-cellular organisms
Nucleus
Contains DNA organized into chromosomes, surrounded by nuclear membrane/envelope
Chromosomes
Linear strands of DNA already wound around histones
Nuclear membrane/envelope
Double membrane that contains nuclear pores for two-way exchange or materials between nucleus and cytosol
DNA
Genetic information, coding regions called genes, linear DNA would around histones then wound into chromosomes
Genes
Coding regions of DNA
Nucleolus
Subsection of the nucleus in which ribosomal RNA is synthesized, 25% of nucleus volume, darker spot
Mitochondria
Power plant of the cells, has inner and outer membrane, can divide independently from nucleus with binary fission, can trigger apoptosis by releasing enzymes into cytoplasm
Outer mitochondrial membrane
Forms barrier with cytosol
Inner mitochondrial membrane
Folded into cristae, contains molecules and enzymes for ETC, contains mitochondrial matrix
Mitochondria intermembrane space
Space between inner and outer mitochondrial membranes
Lysosomes
Single membraned and contain hydrolytic enzymes that can break down substances ingested by endocytosis and cellular waste products. When enzymes released, autolysis can occur
Endoplasmic reticulum
Series of interconnected membranes, continuous with nuclear envelope
Rough ER
Studded with ribosomes
Ribosomes
Permit translation of proteins destined for secretion
Smooth ER
Used for lipid synthesis and detoxification, also transports proteins from the RER to Golgi apparatus
Golgi apparatus
Consists of stacked membrane-bound sacs in which cellular products can be modified, packaged, and directed to specific cellular locations
Peroxisomes
Contain hydrogen peroxide and can break down long chain fatty acids via beta-oxidation. Also participate in phospholipid synthesis and the pentose phosphate pathway
Cytoskeleton
Provides stability and rigidity to the overall cell, which also providing transport pathways for molecules within the cell
Microfilaments
Composed of solid polymerized actin, provide structural protection for the cell (to both compression and fracture) and can cause muscle contraction through interactions with myosin. Also help form the cleavage furrow during cytokinesis in mitosis
Actin
Forms microfilaments
Microtubules
Composed of hollow polymers of tubulin, create pathways for motor proteins (kinesin and dynein) to carry vesicles, contribute to structure of cilia and flagella where they are organized in a 9 +2 structure, attach centrioles and chromosomes during mitosis to help pull sister chromatids apart
Tubulin
Forms microtubules
Kinesin and dynein
Motor proteins whose travel is aided by microtubules
Cilia
Projections from a cell that are involved in the movement of materials along the surface of the cell, structure supported by microtubules in 9+2 pattern
9+2 structure
Nine pairs of microtubules in a ring with two microtubules in the center, cilia and flagella structure
Centrioles
Found in centromeres and are involved in microtubule organization in the mitotic spindle - 9 triplets of microtubules with hollow center
Intermediate filaments
Involved in cell-cell adhesion and maintenance of the integrity of the cytoskeleton by increasing rigidity and anchoring organelles (can withstand a ton of tension)
Examples of intermediate filaments
Keratin and desmin
Epithelial tissues
Covers the body and lines its cavities, protects against pathogen invasion and desiccation, some involved in absorption, secretion, and sensation
Parenchyma
Functional parts of the organ, typically formed by epithelial cells
Epithelial cells polarization
Can be polarized with one side facing human or outside world and other facing blood vessels or structural cells
Simple epithelia
One layer epithelial cells
Stratified epithelia
Many layered epithelial cells
Puesdostratified epithelia
Appear to have multiple layers due to differences in cell heights but are actually only one layer
Epithelia layer classifications
Simple, stratified, puesdostratified
Epithelia shape classifications
Cuboidal, columnar, and squamous
Cuboidal cells
Cube shaped
Columnar cells
Long and narrow
Squamous cells
Flat and scalelike
Connective tissue
Supports the body and provides framework for epithelial cells, forms stroma in most organs by secreting materials (collagen and elastin) to form extracellular matrix
Stroma
Support structure generally formed by connective tissues
Connective tissues examples
Bone, cartilage, tendons, ligaments, adipose tissue, and blood
Histones
Organizing proteins that linear DNA is wound around
Cristae
Infoldings in inner mitochondrial membrane, increase SA for ETC
Mitochondrial matrix
Space inside inner mitochondrial matrix, contain protons will be pumped to intermembrane space and then will flow through ATP synthase to generate ATP during oxidative phosphorylation
Cytoplasmic or extranuclear inheritance
Transmission of genetic material independent of the nucleus
Apoptosis
Programmed cell death
Endosomes
Transport, package, and sort cell material traveling to and from the membrane - can transport to the trans golgi, the cell membrane, or the lysosomal pathway for degradation
Autolysis
When lysosomes release enzymes and apoptosis occurs via cellular component degradation
Exocytosis
Secretion where a secretory vesicle merges with the cell membrane and its contents are released
Golgi apparatus product modification
Addition of groups, addition of signal sequences to direct delivery of the product
Three components of cytoskeleton
Mircofilaments, microtubules, and intermediate filaments
Cytokinesis
Division of materials between daughter cells
Flagella
Involved in movement of the cell itself, structure supported by microtubules in 9+2 pattern
Kinetochores
Complexes that attach microtubules to chromosomes to help pull sister chromatids apart
Tissue types
Epithelial, connective, muscle, and nervous
Basement membrane
Layer of connective tissue keeping epithelial cells together
Lumen
Hollow inside of an organ or tube
Prokaryotes
Do not contain membrane-bound organelles, contain genetic material in single circular molecule of DNA located in the nucleoid region
Nucleoid region
Region where single circular molecule of DNA is location in prokaryotes
Three domains of life
Archaea, bacteria, eukarya
Archaea
Often extremophiles, live in harsh environment (temp, salinity, no light), use chemical sources for energy (chemosynthesis); have similarities to both eukaryotes and bacteria
Archaea similarities to eukaryotes
Start translation with methionine, similar RNA polymerases, histones
Archaea similarities to bacteria
Single circular chromosome, divide by binary fission or budding
Bacteria
Similar structure to eukaryotes, complex relationships with humans including mutualistic symbiosis and pathogenesis
Mutualistic symbiosis
Both organisms benefit from the relationship
Pathogenesis
Harm is caused to one organism in the relationship
Eukarya
Only non-prokaryotic domain
Bacteria shape classifications
Cocci, bacilli, spirilli
Cocci
Spherical bacteria
Bacilli
Rod-shaped bacteria
Spirilli
Spiral-shaped bacteria
Bacterial metabolic classifications
Obligate aerobes, obligate anaerobes, facultative anaerobes, aerotolerant anaerobes
Obligate aerobes
Require oxygen for metabolism
Obligate anaerobes
Cannot survive in oxygen-containing environments and only carry out anaerobic metabolism
Facultative anaerobes
Can survive in environments with or without oxygen and will toggle between metabolic processes based on the environment
Aerotolerant anaerobes
Cannot use oxygen for metabolism, but can survive in an oxygen-containing environment
Cell envelope
Made of cell wall and cell membrane, contain movement of solutes into and out of cell to maintain concentration gradient
Gram staining
Bacteria cell wall classification done with a crystal violet stain followed by a counterstain with safranin
Gram positive
Bacteria that turn purple during gram staining; thick cell wall composed of peptidoglycan and lipoteichoic acid
Gram negative
Bacteria that turn pink-red following gram staining; thing cell wall composed of peptidoglycan and an outer membrane containing phospholipids and lipopolysaccharides
Bacteria movement
Possibly have one, two, or many flagella to move bacterium towards food or away from immune cells
Chemotaxis
Chemical stimulus that causes movement response in bacteria
Bacteria flagella
Contains a filament, a basal body, and a hook
Prokayotes ETC
Uses cell membrane
Prokaryotic ribosomes
Smaller than eukaryotic ribosomes
Eukaryotic ribosomes size
40S and 60S
Prokaryotic ribosome size
30S and 50S
Binary fission
Prokaryotes division where chromosomes replicate while the cell grows in size, until the cell wall begins to grow inward along the midline of the cell and divides it into two identical daughter cells, faster than mitosis
Plasmids
Carries extrachromosomal material in prokaryotes, may contain antibiotic resistance or virulence factors, some are episomes, not considered in genome because not necessary for survival
Episomes
Plasmids that can integrate into the genome
Virulence factors
Traits that increase pathogenicity, such as toxin production, projections that allow attachment to certain kinds of cells, or features that allow evasion of the host’s immune system
Bacterial genetic recombination
Increases bacterial diversity, includes transformation, conjugation, and transduction
Transformation
Occurs when genetic material from the surroundings is taken up by a cell, which can incorporate this material into its genome
Conjugation
Transfer of genetic material from one bacterium to another across a conjugation bridge, form of mating (sexual reproduction), unidirectional from donor male+ (must have sex factor plasmid) to recipient female-, can allow for rapid passing of plasmids
Conjugation bridge
Facilitates transfer of genetic information, made of sex pili
Fertility factor conjugation
Fertility plasmid is transferred from F+ cells to F- cells, making them F+cells, can allow for rapid passing of plasmids (ex. antibiotic resistance) because more cells can share plasmids with others
Hfr cells conjugation
When a donor cells with a sex factor attempts to transfer its entire genome into a recipient, but only a a portion of the genome can be transferred before the bridge breaks. hfr - high frequency of recombination
Transduction
Transfer of genetic material form one bacterium to another via a bacteriophage vector
Transposons
Genetic elements that can insert into or remove themselves from the genomee
Bacterial growth phases
Lag phase, exponential (log) phase, stationary phase, death phase
Lag phase
Bacteria adapts to new local conditions
Exponential (log) phase
Growth increases exponentially
Stationary phase
Resources are reduced, growth levels off
Death phase
Resources are depleted, so bacteria die
Virus makeup
Genetic material, a capsid, and sometimes a lipid-containing envelope
Viruses
Obligate intracellular parasites, cannot survive and replicate out of a hose cell
Virions
Individual virus particles/progeny
Capsid
Protein coat of viruses
Host cell
Cell that virus uses to replicate and reproduce
Bacteriophages
Viruses that target bacteria (do not actually enter, just inject genetic material), contain a tail sheath and tail fibers
Tail sheath
Injects genetic material into a bacterium
Tail fibers
Allows bacteriophage to attach to the host cell
Viral genomes
May be composed of DNA or RNA, could be single or double stranded or circular
Single stranded RNA viruses
May be positive sense or negative sense
Positive sense
Single stranded RNA virus that can be translated by host cell
Negative sense
Single stranded RNA that requires a complementary stand to be synthesized by RNA replicase before translation
RNA replicase
-
Retroviruses
Enveloped and contain a single-stranded RNA genome which can create a complementary DNA stand using reverse transcriptase, DNA strand can then be injected into the genome
Reverse transcriptase
Can synthesize DNA from single stranded RNA
Virus cell infection
Attach to SPECIFIC receptors, can enter the cell by fusing with plasma membrane, endocytosis, or injecting genome into cell
Virus reproduction
Replicates and translates genetic material using the host cell’s ribosomes, tRNA, amino acids, and enzymes
Viral progeny release
Can be released via cell death, lysis, or extrusion
Extrusion
A virus leaving a cell by fusing with its plasma membrane
Bacteriophage life cycles
Lytic and lysogenic cycle
Lytic cycle
Bacteriophage products massive numbers of new virions until the cell lyses, viruses termed virulent
Virulent
Viruses who are in the lytic phase
Lysogenic cycle
Virus integrates into the host genome as a provirus or prophage, reproduces along with the cell, can remain in the genome indefinitely or may leave the genome in response to a stimulus and enter the lytic cycle, can potentially take other bacteria genes with them which leads to transduction
Prions
Infectious proteins that trigger misfiling of other proteins, usually converting alpha helical structures to beta pleated sheets, decreases the solubility of a protein and increases its resistance to degradation which interferes with cell function
Viroid
Plant pathogens that are small circles of complementary RNA that can turn off genes, resulting in metabolic and structural changes, and potentially cell death
Chemosynthesis
Energy generation by some Achaea that uses organic compounds including sulfur and nitrogen based compounds such as ammonia
Fimbriae
Similar to cilia, some bacteria have them
Pathogens/parasites
Bacteria that provide no advantage or benefit to the host and cause disease
Prokaryote cellularity
Single-celled organisms so they must perform all functions required for life and must protect themselves from the environment - however, some prokaryotes live in colonies where they can communicate with each other
Cell wall
Forms outer barrier of the cell, provides structure and controls movement of solutes - present in prokaryotes
Bacteria cell membrane
aka plamsa membrane - similar to eukaryote in that it Is made of phospholipids
Peptidoglycan
Polymeric substance made from amino acids and sugars, provides structure and protection from hosts immune system to bacteria - found in both gram positive and gram negative cells but a lot more in gram positive
Lipoteichoic acid
Found in gram positive cell walls, function unclear, may active human immune response
Periplasmic space
Space between inner and outer cell membrane
Lipopolysaccharides
Trigger immune response in gram-negative bacteria which is much stronger than the response to lipoteichoic acid in gram-positive bacteria
Flagella filament
Hollow, helical structure composed of flagellin
Flagella Basal body
Complex structure that anchors flagellum to cytoplasmic membrane and is motor (rotates up to 300 Hz)
Flagella Hook
Connects the filament and basal body
Sex pili
Appendages on a donor male bacteria that create conjugation bridge, bacteria must have plasmid with sex factor to do this
Sex factors
Plasmids that hold necessary genes to create piles and thus conjugation bridge, can be integrated into host genome with transformation
Vector
A virus that carries genetic material from one bacterium to another
Virus envelope
Could be composed of phospholipids and virus-speciic proteins, sensitive to heat, detergents, and desiccation (easier to kill)
Virus replication DNA
Typically must enter nucleus to be transcribed, retroviruses also travel to nucleus to be integrated into genome
Virus replication positive sense RNA
Stays in cytoplasm and is directly translated into proteins by host cell ribosomes
Virus replication negative sense RNA
Requires synthesis of complementary strand of RNA via RNA replicase then can be translated into proteins
Superinfection
Simultaneous infection of a cell, not common because infection with one strain of phage makes the bacterium less susceptible
