The Cell Flashcards
Cell Theory
All living things are composed of cells
Cell is basic fucntional unit of life
cells arise from pre exsiting cells
Cells carry genetic info passed onto daughter cells
Viruses
contain genetic material but cannot reproduce by themselves; hence not living organisms
Eukaryotic Vs Prokaryotic Main Difference
E: Nucleus contained in membrane
P: No nucleus
Purpose of Membrane Bound Organelles
allows for compartmentalization of functions in E cells; phospholipid bilayer
Purpose of phospholipid bilayer
Inside is hydrophobic and outside is hydrophillic allowing for selective barrier
Nucleus is surrounded by….
nuclear membrane/envelope to keep nuclear environment separate from cytosol
Nuclear Pores
Allow for selective two way transport of material between cytoplasm and nucleus
DNA’s Coding Regions
Genes
Nucleolus
subsection of nucleus where rRNA is synthesized
Outermembrane of Mitochondria
barrier between cytosol and inner enviornment of mitochondria
Inner Membrane (Cristae)
contains the molecules and enzymes needed for ETC
also increase the SA for ETC enzymes
Intermembrane Space and Mitochondrial Matrix
pumping of protons from mitochondrial matrix to intermembrane space produces proton-motive force to generate ATP through OXIDATIVE PHOSPHORYLATION
Why are mitochondrion different from other parts of the cell?
Semi-Autonomous: contain thier own genes and replicate independently
Cytoplasmic/Extranuclear Inheritence
transmission of genetic material independent of nucleus
Apoptosis
killing of the cell; can be initiated by enzymes from ETC in mitochondria being released
Lysosomes
contain hydrolytic enezmyes to breakdown substrates; can lead to apoptosis when autolysis occurs
Autolysis
releasing of enzymes from lysosomes into cell leading to apoptosis
ER Rough
studded with ribosomes to allow for protein translation directly into inner lumen
ER Smooth
lacks ribosomes and used for lipid synthesis
Golgi Apparatus
stacked membrane bound sacs
ER -> Golgi to be modified by addition of groups (carbs, phosphates, sulfates, signal seq)
Modified products repackaged in vesicles and sent to correct location
Exocytosis
vesicles merging with cell membrane to release its contents
Peroxisomes
contain hydrogen peroxide to breakdown long fatty acid chains via B-oxidation, synthesis of phospholipids and pentose phosphate pathway
Cytoskeleton
provides structure to the cell and helps maintain its shape while conduiting transport of materials around cell.
Microfilaments, Microtubules, Intermediate Filaments
Microfilaments
- polymerized rods of actin that are resistant to compression and fracture
- (use ATP to generate movement via attaching to myosin)
- also play a role in cytokinesis by forming ring for cleavage furrow that constricts and splits the cell into 2
Microtubules
- hollow tubulin protein polymers
- primary pathway for kinesin and dynein to carry vesicles
Kinesin and Dynein
motor proteins which carry vesicles
Cilia
micortubule that move material along the surface of the cell
Flagella Eukaroytes
microtubule that move cell itself (sperm)
9+2 Structure for Cilia and Flagella
only in eukaryotic organelles of motility
9 microtubules forming ring with two in the center
Centrioles
found in centrosome, migrate to opposite poles of dividing cell to organize mitotic spindle
microtubules from centrioles attach to chromosomes via kinetochores
Intermediate Filaments
cell-cell adhesions, maintenance of integrity of cytoskeleton (rigidness)
anchor other organelles and withstand lots of tension
Epithelial Cell
covers body and lines cavities for protection against pathogens
absorption, secretion and sensation
polarized (one side faces lumen, other with blood)
Basement Membrane
where epithelial cells are tightly joined to an underlyging layer of connective tissues
Parenchyma
functional parts of organs covered by epithelial tissues (nephrons, hepatocytes)
Simple, Stratified, Pseudostratified Epithelia
One layer, multiple, appearance of multiple but only one
Cuboidal, Columnar, Squamous
cube, long and thin, flat and scale like epithelia shapes
Connective Tissue
framework for the epithelia (stroma or support structure)
Produce and secrete collagen/elastin to from extracellular matrix
Bone, cartilage, tendons, ligaments, adipose and blood
Nucleiod Region
area where concentrated DNA of prokaryotes is found
Archae
Prokaroytes
single celled organisms with genes/metabolic pathways similar to eukaryotes
use alternative sources of energy (photo, chemo, inorganic)
Archae similarities to Eukaroyotes
- RNA polymerases, DNA has histones, start translation with methionine
Archae similarities to Prokaroytes
single circular chromosome, divide by binary fission, similar structure to bacteria
Bacteria
Prokaryote
cell membrane, cytoplasm and flagella (sometimes fimbriae which is like cillia)
bacterial/eukaryotic flagella are different which can lead to targetting and of course antibiotics (targeting smaller bacetrial ribosomes)
Mutualistic Symbiotes
both humans and bacteria benefit from relationship
ex: human gut bacteria produce vitamin K and biotin to precent overgrowth of harmful bacteria
Pathogens/Parasites
harm host, no benefits
live intra or extracellularly
Cocci
spherical bacteria
Bacilli
rod shaped bacteria
Spirilli
spiral shaped bacteria
Obligate Aerobes
bacteria that require oxygen for metabolism
Anaerobes
bacteria that do not require oxygen, use fermentation or other methods
Obligate Anaerobes
bacteria that cannot survive in oxygen due to reactive oxygen radicals reacting causing cell death
Facultative Anaerobes
toggle between metabolic processes (depending on if oxygen is present)
Aerotolerant Anaerobes
don’t use oxygen, but are not harmed by its presense
Prokaryotic Cell Wall
forms outer barrier followed by cell membrane within it to form the envelope
structure and controls movement of solutes into/out of bacterium
Gram Positive Cell Wall
deep purple
Thick Layer peptidoglycan to protect from host immune system
Lipoteichoic Acid
Gram Negative Cell Wall
pink red
Thin Layer Peptidoglycan
outer membrane with lipopolysaccharides to trigger inflmatory response
Flagella Prokaroyte
- movement towards or away food/toxins
Filament: bollow, helical structure made of flagellin
Hook: connects the basal body and filament
Basal Body: anchors flagellum to cytoplasmic membrane and is motor
Chemotaxis
ability to move toward or away chemical stimulus
Plasmids
circular DNA seperate from chromosomal DNA that carry DNA not needed for survival but other uses such as antibiotic resistance
How Prokaryotes Produce ATP
No mitochondria, but cell membrane is used for ETC and ATP generation
Ribosomes Prokaryotes
SMaller subunits than Eukaryotes (30 and 50 vs 40 and 60)
Binary Fission
how prokaryotes reproduce (asexual)
Chromosome binds to cell walll and replicates as cell grows in size
Eventually cell wall/membrane grow inward until it splits into 2 cells
very rapid
Extrachromosomal/Extragenomic Material
Plasmids
Virulence Factors
increase how pathogenic a bacterium is, found in plasmids
Episomes
subset of plasmids which integrate into genome of bacteria
Transformation
integration of foreign material into host genome; gram negative rods carry this out
Conjugation
Bacterial mating
Conjugation bridge is formed where donor male (+) gives genetic material to recpient female (-)
allows for rapid antibiotic resistance and virulence factors in colony
Sex Pili
Involved in forming conjugation bridge in conjugation; found in donor male
Formed if bacteria contain sex factors (F Factor)
F Factor
F+ + F- : F+ replicates its sex factor and donates to the recipient F- to also make it F+
sex factor can be integrated into genome and the entire genome can tried to be donated; usually bridge breaks before this
Hfr
High frequency of recombination for cells that go under conjugation
Transduction
only one of Conjugation and transformation to require a viral vector (bacteriphages)
Bacteriophage takes segment of DNA from Host cell when building within it, it can then infect other host cell with the DNA to incorporate into its genome
Transposons
genetic elements found in both prokaryotes and eukaryotes that can insert and remove themselves from the genome ; can disrupt genes if inserted in coding region of the gene
Bacterial Growth
Lag Phase: bacteria adapting to local conditions
Exponential/Log Phase: growth increases and number increases
Stationary Phase: resources reduced slowing reproduction
Death Phase: bacteria have exceeded the ability of the environment to support the number of bacteria
Basic Virus Structure
genetic material, protein coat (Capsid), envelope with lipids
Viral Genetic Material
DS/SS, RNA/DNA, Linear/Circular
Capsid
protein coat around genetic material that can be covered with lipid based envelope (making it easier to kill)
Obligate Intracellular Parasites
Viruses must replicate genetic information within a host cell as they cannot conduct protein synthesis
Virions
viral progeny made within host cells due to virus hijacking genetic machinery
Tail Sheath
injects genetic material into bacteria
Tail Fibers
help virus identify and connect to host cell
Positive Sense Virus
SS RNA virus genome can be directly translated to functional proteins by ribosomes
Negative Sense Virus
SS RNA virus genome requre complementary seq of the genome before protein synthesis occurs
***REQUIRE RNA REPLICASE TO SYNTHESIZE COMPLEMENTARY STRAND
Retrovirus
enveloped, SS RNA
carry reverse transcriptase to turn RNA into DNA to incorporate into host genome DNA and only way to cure it is by killing infected cell (HIV!!)
Process of Infection
viruses only infect specific cells with specific receptors
Enevloped virus will fuse with plasma membrane to allow virion to enter host cell ; sometimes done through endocytosis by host cell as a mistake
Tail sheath can form pores on membrane to allow for transfer of material
Translation and Progrny Assembly
For virus to produce, translation occurs
DNA Virus: go into nucleus to become mRNA then proteins
Positive Sense RNA: stay in cytoplasm for ribosomes to trasncribe
Negative Sense RNA: RNA replicase first forms complementary and then translated to proteins
Retrovirus: RNA becomes DNA via reverse transcriptase and then goes to nucleus
Once protein made (often capsid), then encapture viral genome in the form it initially was (DNA, SS RNA, etc when entering host)
Progeny Release
1) Cell death leading progeny to spill out
2) Host cell lyses due to number of progeny (disadvantageous)
3) Extrusion: fuses with plasma membrane; allows for virus to continually use the host cell
Productive Cycle
Extrusion, where host cell is live and used by the virus
Lytic Cycle/Virulent
bacteriphage makes maximal use of host cell leading to cell lysing; can infect other bacteria.
Lysogenic Cycle
If no lysing occurs, it becomes a provirus/prophage
virus is replicated as bacteria reproduces, will eventually go into lytic phase due to enviornmental factors
Superinfection
simultaneous infection by multiple phages; once a phage infects, bacteria is usually less susceptible to this
Prions
infectious proteins/nonliving things; cause disease by misfolding proteins
often characterized by alpha helical conversion to B pleated sheet
Viroids
pathogens with short, circular SS RNA to infect plants; bind to RNA sequences to silence genes
few human viroids exist (HDV)
