Zoo- Sep 11

Perceptive integrates grades (evaluation and self/peer scoring) and posts them to Canvas; verify consistency with Canvas; report discrepancies.
Milestone 1 objective: select an endangered species as a team; submit top 3 choices (no duplicates); first-come-first-served selection.
Submission options: text entry or file upload; also upload the team checklist; missing checklist = 50% deduction.
Criteria: species must currently be listed as endangered (USFWS resource provided); helps access funding and research/conservation data.
Timeline: milestone 1 due date set; earlier submission improves chance of getting your top pick; comments will indicate the assigned species.

ATP is the energy currency; mitochondria transform ADP to ATP; ATP is reused.
Cells generate and recycle ATP as energy is required; large-scale organismal energy demands are met via this cycle.
Humans have ~ $3.0\times 10^{13}$ cells, each maintaining ATP turnover continually; energy extraction from food restores ATP.

Enzymes are proteins whose 3D shape dictates function; many enzymes end with the suffix "-ase".
They act as catalysts to lower the activation energy of reactions (activation energy is the energy needed to start a reaction).
Enzymes act on specific substrates at the active site to form an enzyme–substrate complex; bonds rearrange to form products; products are released and the enzyme is free to catalyze again.
Enzymes are reused and remain active across many reaction cycles.
In shorthand: $E<em>a^{with\ enzyme} < E</em>a^{without\ enzyme}$

Substrate binds to a specific active site; this site is complementary in shape.
Formation of the enzyme–substrate complex lowers the energy barrier for the reaction to proceed.
Enzyme action can either join substrates together or split them apart.

Lactase is the enzyme that digests lactose (a sugar in dairy).
Lactose intolerance arises when lactase levels are low, making lactose digestion harder.
This illustrates enzyme specificity and the consequence of enzyme availability on digestion.

Temperature and pH affect enzyme shape; outside optimal conditions, enzymes denature and lose function.
Human body temperature is about $T_{opt} \approx 37^{\circ}C \approx 98.6^{\circ}F$ ; other species have different optima (e.g., dogs closer to $100^{\circ}F$ ).
Enzymes are proteins; their structure is sensitive to environmental conditions.

PETase is an enzyme that can break down PET plastic; it acts like molecular scissors, cleaving polymer chains into monomers.
Early work produced improved versions that digest PET faster (roughly a 20% improvement reported in some studies); newer data suggest faster timelines (weeks to days for degradation under certain conditions).
Important caveat: not all plastics are substrates for PETase; environment and conditions greatly influence efficiency; ongoing research is needed before widespread application.

Pacific Garbage Patch is a large plastic concentration in ocean gyres; plastics break down into microplastics over time.
Marine life is harmed through ingestion and entanglement; plastics can disrupt food webs (e.g., sea turtles mistaking bags for jellyfish).
Plastic takes centuries to degrade; remediation requires reducing input and developing effective degradation strategies.

Enzymes provide examples of how biology can contribute to remediation (e.g., PETase); but real-world deployment requires understanding optimal conditions and ecological impacts.
In studying endangered species projects, consider how conservation strategies intersect with biology (genetics, habitat, funding, policy).

Enzymes lower activation energy and are highly substrate-specific; structure dictates function.
Active site binding forms an enzyme–substrate complex; products released; enzyme reused.
Temperature and pH critically affect enzyme activity; optimal conditions vary by organism.
PETase illustrates enzyme-assisted plastic degradation; efficacy depends on plastic type and environment.
Endangered species selection relies on up-to-date listings and non-duplicative, team-based planning.