answers correctly solved (29 pgs)
Dr. Keck studies - correct answer ✔Ichthyology
7 criteria for life - correct answer ✔Organization, Metabolism, Growth,
Homeostasis, Response to Stimuli, Adaptation, Reproduction
How are bacteria, archaea, and eukaryotes are related - correct answer
✔Last Universal Common Ancestor (LUCA)
timeline for early earth: earths formation and the first single celled organisms -
correct answer ✔4.5 bya Earth was formed, 4 bya the crust was solidified,
3.5 bya we find the oldest fossils of microorganisms (all of these are
prokaryotes), prokaryotes dominant between 3.5-2 bya (morphologically they
haven't changed very much)
4 steps leading to cellular life: flow chart and early experiments - correct
answer ✔1. Abiotic synthesis of small organic molecules (monomers) C+H =
organic molecule.2. Monomers joined together to form polymers (proteins,
nucleic acids)3. Origin of self-replicating molecules (inheritance of traits) and
proteins and polynucleic acids4. Packaging of these organic molecules into
protobionts. Aggregrates of abiotically produced molecules that maintain an
internal chemical environment and exhibit some of the properties associated
with life (metabolism, excitability). This goes to the common ancestor of all
known life. Evidence: Energy from lightning, UV radiation, Oparin and
Haldane in 20's: abiotic synthesis of organic molecules in lab. Hypothesis:
conditions on primitive earth favored chemical reactions that synthesize
organic compounds from inorganic precursors. Recreate early environment:
no oxygen but water, methane, and ammonia.
,Where did the four steps leading to cellular life occur? - correct answer
✔Transfer of information: Heritability (early amino acids, early nucleic acids).
RNA world: founder for replication, even simple RNA molecules are catalytic,
contains information: nucleotide bases. Protobionts: organic molecules that
have tendency to aggregate membrane like structures to form easily and even
happen in lab (microspheres form spontaneously and can replicate by
pinching off new spheres). Endosymbiotic theory: cells become more
complete before life really takes off
Prokaryotes vs. Eukaryotes - correct answer ✔Prokaryotes lack membrane
bound organelles, almost all unicellular, lack histones in their DNA, circular
DNA, replication occurs quickly and in cytoplasm.Eukaryotes have membrane
bound organelles, and replication occurs in the nucleus.
Bacteria vs. archaea - correct answer ✔Bacterial cells walls contain
peptidoglycan
Archaeal cells walls do not
Gram staining - correct answer ✔technique used to differentiate 2 large
groups of bacteria based on their cell wall constituents.
Gram positive (cell wall) - correct answer ✔simple, thick cell walls composed
of large amounts of peptidoglycan
gram negative (cell wall) - correct answer ✔layered cell wall with less
peptidoglycan more resistant to host immune system and antibiotics
Bacterial Movement and Reproduction - correct answer ✔1. Flagellum: basal
apparatus rotates the flagellum and propels the cell.2. Corkscrew movement
of spirochete3. Glide over jets of slimy secretion
, RNA world - correct answer ✔contains information (nucleotide bases),
catalytic (they can do some chemical reactions), it is self-replicating
Protobionts - correct answer ✔organic molecules have tendency to
aggregate membrane-like structures form easily and even happen in lab
experiments. microspheres form spontaneously and can replicate by pinching
off new spheres.
Endosymbiosis - correct answer ✔theory: evolutionary theory of the origin of
eukaryotic cells from prokaryotic organisms.
Viruses and life - correct answer ✔are alive but are completely dependent on
hosts
Why is it difficult to identify species of bacteria and archaea? - correct answer
✔limited morphology, hard to sample, hard to culture, lots of gene flow, know
about 10K species but estimated in the millions
The environment of Archaea - correct answer ✔extreme enviornments
Why microbiomes might differ between regions on a body and between
individuals - correct answer ✔kids that don't get out much have small micro
biomes. Diet, hygiene changes micro biomes.
Organisms attempt to grow and reproduce in a given environment as
efficiently as possible. - correct answer ✔Plants and Fungi
The benefits and problems faced in the transition from an aquatic to a
terrestrial environment - correct answer ✔pros: nutrients, less predation,