Home / Flashcard library / High school & admissions / IB Biology / Interaction and Continuity

High school & admissions

IB Biology — Interaction and Continuity flashcards

10 of 78 cards free to study here · 2 topics · the whole deck is built into Willys

Themes C (Interaction and interdependence) and D (Continuity and change) of the IB Biology course: enzymes, respiration, photosynthesis, signalling, defence, ecology, DNA, cell division, inheritance, homeostasis, selection and climate change. HL content is tagged HL.

Get the app All IB Biology decks

Learn deck · part of IB Biology · written against: IB Diploma Programme IB Biology subject guide for first assessment 2025 (themes A–D); SL and HL in one deck, HL-only cards under subtopic tags starting HL. Updated 2026-10-10.

Study the free sample

10 cards from the deck as they are. Flip, rate yourself, filter by topic; your progress stays in this browser.

The 10 sample cards as a list
  1. How does the induced-fit model refine the simple lock-and-key picture of enzyme action?
    In induced fit, the active site is not rigid: binding of the substrate causes a small change in the enzyme's shape that grips the substrate more tightly and strains its bonds, lowering the activation energy.
    Interaction and Interdependence › Molecules
  2. Below an enzyme's optimum temperature, why does warming the mixture speed up the reaction?
    Molecules gain kinetic energy, so substrate and enzyme move faster and collide more often, and more of those collisions have enough energy to react.
    Interaction and Interdependence › Molecules
  3. What makes ATP suitable as the cell's immediate energy currency?
    Hydrolysis of ATP to ADP and phosphate releases a convenient, moderate amount of energy in one step; ATP is soluble, moves easily within the cell and is rapidly regenerated by respiration.
    Interaction and Interdependence › Molecules
  4. How does anaerobic respiration in humans differ from anaerobic respiration in yeast?
    Human muscle converts pyruvate to lactate with no CO₂ released; yeast converts it to ethanol and CO₂. Both yield only 2 ATP per glucose from glycolysis.
    Interaction and Interdependence › HL Molecules
  5. How does a simple respirometer measure the rate of respiration of germinating seeds?
    An alkali such as soda lime absorbs the CO₂ given off, so the gas volume falls as oxygen is used; the distance a coloured liquid moves along a capillary tube per minute gives the rate.
    Interaction and Interdependence › Molecules
  6. Why is DNA replication described as semi-conservative, and why does that make copying accurate?
    Each new molecule has one original strand and one new strand; the old strand acts as a template, and complementary base pairing determines which nucleotide is added at each position.
    Continuity and Change › Molecules
  7. Why is PCR so useful for COVID-19 testing and forensic science?
    PCR makes millions of copies of a chosen DNA sequence, so tiny samples (a nasal swab after reverse transcription of viral RNA, or a trace of blood) become enough to detect or profile.
    Continuity and Change › Molecules
  8. Apart from one base, why does an mRNA have the same base sequence as the coding (sense) strand of its gene?
    mRNA is built complementary to the template strand, and so is the coding strand; both therefore carry the same sequence, except that RNA has uracil where DNA has thymine.
    Continuity and Change › Molecules
  9. Why are there 64 codons when only 20 amino acids are coded for?
    Each codon is three bases from four, giving 43=644^3 = 64 combinations. The code is degenerate: most amino acids have more than one codon, and three codons are stop signals.
    Continuity and Change › Molecules
  10. Using the genetic code, which amino acid sequence does the mRNA AUG GCU UGG UAA encode?
    Met–Ala–Trp, then stop: AUG = methionine, GCU = alanine, UGG = tryptophan and UAA is a stop codon.
    Continuity and Change › Molecules

Unlock the whole deck

You are studying a free 10-card sample. All 78 cards of IB Biology — Interaction and Continuity, the other 2 IB Biology decks, and spaced-repetition scheduling are built into Willys. 14-day free trial, then $14.99 a year.

Get the app

In Willys, tap Exam Library at the top of your Decks (or Browse Exam Library… under the + button), find the exam on its shelf or by search, tick it and tap Add.

More IB Biology decks

Unity, Diversity and FormPractice Questions

← All IB Biology decks, with the study guide and topic outline.

About these cards

Review status: Second-reader reviewed, with corrections applied.

Checked against:

  • IB Diploma Programme subject guide (topic outline only; no text copied)
  • Tag order follows the IB Diploma Programme Biology guide for first assessment 2025 (themes A–D across four levels of organisation).
  • OpenStax Biology 2e, consulted as a reference; no text copied.
  • Also checked against the NOAA Global Monitoring Laboratory's monthly Mauna Loa CO₂ record, the US National Park Service's Yellowstone wolf ecology page and Open RN Nursing Fundamentals (CC BY 4.0) (reference only; no text copied).

These are independent study notes written for Willys. They are not official exam material, may contain mistakes, and are no substitute for your course, your teacher or the exam owner's own publications. Found an error? Tell us — corrections ship as a new version of the deck.

International Baccalaureate® is a registered trademark of the International Baccalaureate Organization, which is not affiliated with, and does not endorse, this product.

Use of these pages is covered by our Terms of Use.