Week 5 — Readings & Resources · Energy, Enzymes & Metabolism

Course: Introduction to Biology — General Biology I (BIOL 101) · Silver Oak University (fictional sample) · Prof. Castellano
Objective covered: Objective 4 — Energy & thermodynamics, ATP as the cell's energy currency, and how enzymes lower activation energy and respond to temperature and pH.

How to use this page

Everything here is a link to an external resource — open it in your browser, the same way you'd open a YouTube link. Nothing needs to be downloaded.

This week's load is deliberately light: 2 short videos + 2 short readings, grouped by the ideas from the lecture, plus a couple of optional free references. Watch or read one item per group and you're ready for the quiz; do all of them and you'll be very comfortable. Total time is roughly 35–45 minutes if you do everything, far less if you pick one per group.

Order that matches the lecture: ① energy & ATP → ② enzymes & activation energy → ③ what changes an enzyme's rate (temperature, pH).

A habit to start now: before you trust any biology claim — in these resources or anywhere — ask the questions from class: Does this say a cell "makes" energy (it shouldn't)? Does it claim "hotter is always faster" for an enzyme (it isn't)? Does it treat the enzyme as "used up" (it's reused)?

① Energy, Thermodynamics & ATP

Maps to Lecture Segments 2–3. A cell never makes energy — it captures and transforms it (1st law), always paying an entropy tax (2nd law). The spendable form of that energy is ATP, recharged from ADP.

Reading — "Energy and Metabolism" (OpenStax Biology 2e, §6.1)
🔗 https://openstax.org/books/biology-2e/pages/6-1-energy-and-metabolism
Why it's assigned: the cleanest plain-language version of metabolism, anabolic vs. catabolic pathways, and where ATP fits — the same framing we used in class. Free to read online, no account needed.
⏱ ~10 min

Video — "ATP & Respiration: Crash Course Biology #7" (CrashCourse)
🔗 https://www.youtube.com/watch?v=00jbG_cfGuQ
Why it earns the click: Hank Green explains the "economy" of cellular energy and the role of ATP — watch the first ~4 minutes (through "Adenosine Triphosphate") for this week's ATP idea. (The later glycolysis/Krebs/ETC sections are a perfect head start on next week.)
⏱ ~13 min (first ~4 min are this week's part)

② Enzymes & Activation Energy

Maps to Lecture Segments 5–6. The heart of the week: an enzyme is a reusable protein catalyst that lowers activation energy (the "energy hill"), binding its specific substrate in an active site (lock-and-key → induced fit).

Video — "Enzymes (Updated)" (Amoeba Sisters)
🔗 https://www.youtube.com/watch?v=qgVFkRn8f10
Why it earns the click: a friendly ~6-minute tour of exactly our vocabulary — active site, induced fit, substrate, cofactor/coenzyme — plus how pH and temperature affect enzymes and what denaturation is. It maps onto the board notes almost one-to-one.
⏱ ~6 min

Reading — "Enzymes" (OpenStax Biology 2e, §6.5)
🔗 https://openstax.org/books/biology-2e/pages/6-5-enzymes
Why it's assigned: the plain-language version of how enzymes lower activation energy, the active site and substrate specificity, lock-and-key vs. induced fit, and how temperature and pH (and cofactors) affect them — read down through "Enzyme Active Site and Substrate Specificity." Free to read online.
⏱ ~10 min

③ What Changes an Enzyme's Rate (Temperature & pH)

Maps to Lecture Segment 6. The line to carry out of this week: enzyme rate rises to an optimum (about body temperature for yours) and then crashes when the enzyme denatures — and the same idea holds for pH.

Article — "Enzymes and the active site" (Khan Academy, Biology)
🔗 https://www.khanacademy.org/science/ap-biology/cellular-energetics/enzyme-structure-and-catalysis/a/enzymes-and-the-active-site
Why it's assigned: a short, clear article on the active site, activation energy, and how environment (temperature, pH) shapes enzyme activity — a good written companion to the temperature curve we drew in class.
⏱ ~8 min

Optional one-stop references (free online)

• Khan Academy — "Energy and enzymes" (Biology unit). A free unit with short articles and videos covering free energy, ATP, and enzymes — a good place to return to all term.
  🔗 https://www.khanacademy.org/science/biology/energy-and-enzymes
• OpenStax Biology 2e — "ATP: Adenosine Triphosphate" (§6.4). A focused, free-to-read section on the ATP↔ADP cycle if you want the deeper version of this week's energy-currency idea.
  🔗 https://openstax.org/books/biology-2e/pages/6-4-atp-adenosine-triphosphate

Pick-one quick path (≈16 min total)

In a hurry? Do exactly these two and you'll be ready for the quiz:
1. Watch "Enzymes (Updated)" (group ②).
2. Read the first part of "Energy and Metabolism" §6.1 for ATP (group ①), and skim "Enzymes and the active site" for the temperature/pH effects (group ③).

Heads-up (links rot): these point to outside sites that occasionally move or rename pages. If a link ever fails, tell Prof. Castellano and use the OpenStax or Khan Academy references above in the meantime.