the cell Flashcards
cell theory
all living things are composed of cells, the cell is basic functional unit of life, cell only arise from existing cells
nucleus
contains all genetic material needed for replication of the cell, surrounded by nuclear envelope; nuclear pores allow for selective exchange
nucleolus
subsection of nucleus where ribosomal RNA is synthesized
mitochondria
contain outer membrane, which serves as a barrier, and an inner membrane with many infolds (christae) to increase surface area for ETC; intermembrane space=between the 2 membranes; matrix= inside inner membrane; capable of inducing cell apoptosis
lysosomes
contain hydrolytic enzymes that can break down cellular waste or endocytosed products; contain these enzymes in an organelle to prevent cell damage
smooth ER
lipid synthesis and detoxification of drugs and poisons; transports proteins from RER to golgi in vesicles
golgi
modifies and sorts cellular products, then sends them off to correct location inside the cell
peroxisomes
contain hydrogen peroxide to break down long fatty acid chains; synthesize phospholipids
cytoskeleton
provides structure to the cell and serves as conduit for transporting materials around cell; composed of microfilaments, microtubules, and intermediate filaments
microfilaments
made up of actin rods, which can allow for movement in cell; involved in division of cell materials during cytokinesis
microtubules
polymers of tubulin; provide pathways on which motor proteins (kinesin, dynein) can move
cilia
projections from a cell involved with movement of materials along the cell surface; ex. cilia line the respiratory tract
flagella
involved with movement of the cell itself, such as movement of sperm cells
9+2 structure
found in flagella and cilia or eukaryotic organelles involved with motility; 9 pairs of microtubules in outer ring and 2 microtubules in center
epithelial tissue
covers the body and lines its cavities; tightly joined to each other and to the basement membrane, which lies underneath; makes up the parenchyma/the functional parts of most organs
connective tissue
supports the body, provides framework for epithelial cells to carry out their function; main contributors to the stroma (support structure); produce collagen and elastin to form extracellular matrix; ex. bone, cartilage, tendons, ligaments, blood
nucleoid region
area of prokaryotic cells where the single circular molecule of DNA is located
archaea
single-celled prokaryotes, that contain some similarities to eukaryotes regarding their genes and metabolic pathways; resistant to many antibiotics
bacteria
prokaryotic cells; some are mutualistic symbiotes- and provide benefits to humans, while others are parasites
cocci
spherical bacteria
bacilli
rod-shaped bacteria
spirilli
spiral-shaped bacteria
obligate aerobes
bacteria that require oxygen for metabolism
anaerobes
bacteria that use type of metabolism that doesn’t require oxygen such as fermentation; obligate anaerobes die in presence of O2, facultative anaerobes can use O2 for respiration if present, and aerotolerant anaerobes aren’t harmed but can’t use it
prokaryotic cells
single celled-each cell must perform all functions needed for life; has cell wall to protect itself, which can be gram negative or positive; cell membrane is used for electron transport chain in aerobes; have ribosomes, but subunits are different sizes than eukaryotes
gram positive bacteria
cell wall has thick layer of peptidoglycan, which absorbs violet stain; also has lipoteichoic acid
gram negative bacteria
cell walls are thin, contain much smaller amounts of peptidoglycan, which doesn’t absorb purple stain, so appears pink-red from safranin counterstain; outer membrane has lipopolysaccharides
binary fission
asexual reproduction in prokaryotes; circular chromosome replicates and cell grows in size; plasma membrane and cell wall grow inward at midline to produce two identical daughter cells
plasmids
source of extragenomic DNA in bacteria that may carry beneficial genes such as antibiotic resistance or virulence factors, which increase how pathogenic the bacteria is
transformation
integration of foreign genetic material from the environment into host genome; usually comes from other bacteria which lysed
conjugation
bacterial form of mating/sexual reproduction; two cells form conjugation bridge that allows transfer of genetic material; transfer from donor male (+) to recipient female (-); bridge made from sex pili found on male; male must have sex factor, F (fertility) factor to make pilus; during conjugation, F+ cell will replicate and donate F factor so donor will become F+
transduction
genetic recombination that requires a viral vector (virus that carries genetic info from one bacteria to another)
transposons
genetic elements capable of inserting and removing themselves from the genome; if inserted into coding region, may disrupt gene
bacterial growth curve
Starts with lag phase, bacteria adapts to new environment, no growth; then exponential phase: huge reproduction and increase in number of bacteria; then stationary phase because resources reduced from huge growth; last death phase: depletion of resources, so large reduction, most bacteria die
Viruses
not living, because acellular!; has protein coat (capsid), and genetic material, but requires host cell to replicate and express genetic info; viral progeny produced by host is called virions
bacteriophages
viruses that specifically target bacteria; they inject genetic material, while protein shell doesn’t enter cell; has tail sheath which acts like a syringe and tail fibers which help recognize the host cell and bind
Positive sense RNA virus
genome may be directly translated to functional proteins by ribosomes of host cell
Negative sense RNA virus
require synthesis of rna strand complementary to negative sense strand, which is then used for protein synthesis in host cell
retrovirus
contain reverse transcriptase, to synthesis DNA from RNA, which is then integrated into host genome
lytic cycle
bacteriophage replicates and makes lots of virions; once cell is swollen with virions, cell lyses and other bacteria can be infected
lysogenic cycle
virus replicated as the bacterium reproduces because it is integrated into host genome; at some point environmental factors may cause virus to leave genome and revert to lytic cycle
prions
infectious particles that cause disease by triggering misfolding of other proteins
viroids
small pathogens consisting of short, circular single-stranded RNA that infect plants; can bind to RNA sequences and silence genes in plant genome
