exam 2 - study guide 6 Flashcards
major characteristics of archaea
Never contain peptidoglycan in their cell walls, many proteins. Have membrane lipids with ether linkages between glycerol backbone and sidechains. Unique small subunit rRNA sequences, have histone-like proteins associated their DNA.
Which characteristics do Archaea share/have in common with the other prokaryotic Domain, Bacteria? How do they differ
Have nucleus and membrane-bound organelles; unicellular - possess a single circular chromosome
archaea have a composition of membrane lipids
are any bacteria or archaea non-culturable?
most are unculturable
what are the three major culturable groups of arachea
methanogens, exterme halophiles, thermoacidophiles
methanogens
produce methane as their main metabolic product
extreme halophiles
Found salt lakes, soda lakes, and brines. Can grow in 32% NaCl, require at lease 9%. Produce pigments
thermoacidophiles
Found near deep sea volcanic vents & fissures that release sulfurous gases and hot vapors or found in hypothermal vents in deep sea. Pyrodictium occultom cannot grow below 82C, 105C is optimum. Strain 121 grows at 121 C. Some grow at pH 2, lyse at neutral pH.
Which culturable group of Archaea is most likely to be found in the gastrointestinal tract of humans and animals; as well as in many sediments/water saturated habitats? What gas do they produce?
methanogens, produce methane
are any archaea known to cause disieases of humans, animals, or plants
None are known to
What components are found in all prokaryotic cells? Which components of prokaryotic cells can be found in or on some, but not all, prokaryotic cells?
No peptidoglycan but have a similar molecules: pseudopeptidoglycan
Have cell wall, membrane, protoplasm/cytoplasm, ribosomes, nucleoid
all other organelles vary in occurrence
eukaryote traits
Eukaryotic cells are larger, are more complex, have an abundance of membrane-enclosed organelles, most contain sterols, cytoplasmic ribosomes are 80S.
How does the structure of human and animal cells differ from that of cells of green plants?
Plant cells have rigid cell walls, a large central vacuole, and chloroplasts. Animal cells have centrosomes and lysosomes.
What is mitosis and which type of cells carry it out?
Occurs before cell division, make copies of chromosomes for daughter cells. Occurs in eukaryotes.
which types of cells have cellulose in their walls? Which have chitin in their walls?
Plant cell walls contain cellulose. Fungal cell walls have chitin.
apoptosis
membrane damage leading to leakage of cytochrome c or proteins
necrosis
loss of membrane potential via membrane permeability. Results in fail oxidative phosphorylation and loss of ATP.
mitochondria
Mitochondria generate ATP, double lipid bilayer, contains ccc DNA and 70S ribosomes.
- Endosymbiotic theory – evolved from bacterial cells
nucleolus
region in nucleus where rRNAs are synthesized
chloroplast
Site of photosynthesis found in plants and algae. Harvest sunlight to generate ATP. Contain ccc DNA & 70S ribosomes, double lipid bilayer
- Endosymbiotic theory – evolved from cyanobacteria
actin filaments
allow cell movement, polymer of actin polymerize & depolymeriz
microtubules
– long hollow structures made with tubulin, make up mitotic spindles, framework for organelle and vesicle movement
intermediate filaments
provide mechanical support, made of keratins
what are ligands and receptors
ligand - – a molecule that binds to a specific membrane receptor
receptor - membrane protein that binds to specific molecule, allowing cell to sense & adjust to its environment.
which specific membrane proteins on the surface of some human cells are receptors that are recognized and bound the COVID-19 virus
angiotensin-converting enzyme 2 (ACE2) and transmembrane protease, serine 2
selective toxicity
target/harm pathogens, does not harm host
antifungal drugs
inhibit glycan biosynthesis and chitin synthesis, leading to cell death
includes axoles, polyenes, and allyamines to disrupt the fungal membrane, preventing fungal growth
differences and similarities between pro and euk
Differences: Prokaryotes lack nucleus, their DNA is in the region called the nucleoid. Prokaryotes lacks membrane-bound organelles while eukaryotes have many organelles with major functions. Prokaryotes are simpler and smaller and typically single-celled.
Similarities: Both have a plasma membrane, cytoplasm, ribosomes, and DNA.
Of the 3 domains, which have histone proteins associated with DNA
eukaryotes
What evidence supports the endosymbiotic theory of origin of modern eukaryotic cells
modern eukaryotic cells may be the result of infection of one cell type to another cell type
Which eukaryotic organelles seem most likely to have originated from prokaryotic ancestors; and what is the evidence for this?
Modern eucaryotic cells may be the result of infection of one cell type to another cell type. Mitochondria and chloroplasts seem to have originated from prokaryotes because they carry DNA for some ribosomal proteins, rRNA for 70S ribosomes, nuclear DNA encodes some components of these organellar ribosomes. Double membrane surrounds both, division through binary fission, mitochondrial DNA sequences is comparable to prokaryotic rickettsias
what is eukaryogenesis
event that led to modern eukaryotic cells
What type of prokaryotes currently still alive on Earth are considered to be most closely related to the prokaryotic host cell that was infected by another prokaryote about 2.7 billion years ago, giving rise eventually to modern-day eukaryotic cells that contain organelles?
asgard/asgardarchaeota
symbiosis
living together of 2 dissimilar organisms
