exam 2 - study guide 6

Question 1

major characteristics of archaea

Answer 1

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.

Question 2

Which characteristics do Archaea share/have in common with the other prokaryotic Domain, Bacteria? How do they differ

Answer 2

Have nucleus and membrane-bound organelles; unicellular - possess a single circular chromosome
archaea have a composition of membrane lipids

Question 3

are any bacteria or archaea non-culturable?

Answer 3

most are unculturable

Question 4

what are the three major culturable groups of arachea

Answer 4

methanogens, exterme halophiles, thermoacidophiles

Question 5

methanogens

Answer 5

produce methane as their main metabolic product

Question 6

extreme halophiles

Answer 6

Found salt lakes, soda lakes, and brines. Can grow in 32% NaCl, require at lease 9%. Produce pigments

Question 7

thermoacidophiles

Answer 7

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.

Question 8

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?

Answer 8

methanogens, produce methane

Question 9

are any archaea known to cause disieases of humans, animals, or plants

Answer 9

None are known to

Question 10

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?

Answer 10

No peptidoglycan but have a similar molecules: pseudopeptidoglycan
Have cell wall, membrane, protoplasm/cytoplasm, ribosomes, nucleoid
all other organelles vary in occurrence

Question 11

eukaryote traits

Answer 11

Eukaryotic cells are larger, are more complex, have an abundance of membrane-enclosed organelles, most contain sterols, cytoplasmic ribosomes are 80S.

Question 12

How does the structure of human and animal cells differ from that of cells of green plants?

Answer 12

Plant cells have rigid cell walls, a large central vacuole, and chloroplasts. Animal cells have centrosomes and lysosomes.

Question 13

What is mitosis and which type of cells carry it out?

Answer 13

Occurs before cell division, make copies of chromosomes for daughter cells. Occurs in eukaryotes.

Question 14

which types of cells have cellulose in their walls? Which have chitin in their walls?

Answer 14

Plant cell walls contain cellulose. Fungal cell walls have chitin.

Question 15

apoptosis

Answer 15

membrane damage leading to leakage of cytochrome c or proteins

Question 16

necrosis

Answer 16

loss of membrane potential via membrane permeability. Results in fail oxidative phosphorylation and loss of ATP.

Question 17

mitochondria

Answer 17

Mitochondria generate ATP, double lipid bilayer, contains ccc DNA and 70S ribosomes.
- Endosymbiotic theory – evolved from bacterial cells

Question 18

nucleolus

Answer 18

region in nucleus where rRNAs are synthesized

Question 19

chloroplast

Answer 19

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

Question 20

actin filaments

Answer 20

allow cell movement, polymer of actin polymerize & depolymeriz

Question 21

microtubules

Answer 21

– long hollow structures made with tubulin, make up mitotic spindles, framework for organelle and vesicle movement

Question 22

intermediate filaments

Answer 22

provide mechanical support, made of keratins

Question 23

what are ligands and receptors

Answer 23

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.

Question 24

which specific membrane proteins on the surface of some human cells are receptors that are recognized and bound the COVID-19 virus

Answer 24

angiotensin-converting enzyme 2 (ACE2) and transmembrane protease, serine 2

Question 25

selective toxicity

Answer 25

target/harm pathogens, does not harm host

Question 26

antifungal drugs

Answer 26

inhibit glycan biosynthesis and chitin synthesis, leading to cell death includes axoles, polyenes, and allyamines to disrupt the fungal membrane, preventing fungal growth

Question 27

differences and similarities between pro and euk

Answer 27

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.

Question 28

Of the 3 domains, which have histone proteins associated with DNA

Answer 28

eukaryotes

Question 29

What evidence supports the endosymbiotic theory of origin of modern eukaryotic cells

Answer 29

modern eukaryotic cells may be the result of infection of one cell type to another cell type

Question 30

Which eukaryotic organelles seem most likely to have originated from prokaryotic ancestors; and what is the evidence for this?

Answer 30

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

Question 31

what is eukaryogenesis

Answer 31

event that led to modern eukaryotic cells

Question 32

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?

Answer 32

asgard/asgardarchaeota

Question 33

symbiosis

Answer 33

living together of 2 dissimilar organisms