Midterm Practice Exam (ungraded) · Weeks 1–7 (Objectives 1–4)

Course: Introduction to Biology — General Biology I (BIOL 101) · Silver Oak University (fictional sample) · Prof. Castellano
What this is: a low-stakes rehearsal for the cumulative midterm. It mirrors the real exam's blueprint — same coverage, item-type mix, length, and concept-, scenario-, and quantitative-pocket difficulty — but is built from fresh item-bank variants and shares none of the live midterm's questions.
Settings: ungraded (0 points) · unlimited attempts · feedback shown after submission · opens before the exam window so you can prepare.

This is the human-readable practice exam with its vetted answer key and feedback (released after submission). The import-ready Classic QTI 1.2 is in O-practice-exam-week-08-qti.xml (generated by a validated Python script — parses with 20 items). The Canvas placement block is at the bottom.

Integrity note for students. Every item here is a fresh variant — a new scenario and wording — with a pre-vetted answer. None of these are the live midterm questions. Working them builds the skill the midterm tests, honestly. The paired live exam is L-midterm-week-08.md.

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Blueprint (mirrors the midterm)

Coverage is proportional to teaching time, matching the real exam: Obj 1 = 3 · Obj 2 = 6 · Obj 3 = 4 · Obj 4 = 7. (The actual midterm items are not listed here — only the shared structure.)

#	Type	Concept	Objective	Week
1	Multiple choice	Characteristics of life (seed vs. flame)	1	1
2	Multiple choice	Levels of organization, smallest → largest	1	1
3	Multiple choice	Controlled experiment — the dependent variable	1	1
4	Multiple choice	pH: which is most acidic? (quantitative)	2	2
5	Multiple choice	Ionic bond (electron transfer)	2	2
6	Matching	Water's properties → everyday observation	2	2
7	Multiple choice	Carbohydrates — structure→function (starch vs. cellulose)	2	3
8	Multiple choice	Nucleic-acid monomers (nucleotides)	2	3
9	Multiple answer	The four macromolecule classes	2	3
10	Multiple choice	SA:V — which cube has the highest ratio? (quantitative)	3	4
11	Multiple choice	Prokaryote vs. eukaryote (the nucleus)	3	4
12	Matching	Membrane-transport term → description	3	4
13	True / False	Plant cells & mitochondria misconception	3	4
14	Multiple choice	Enzymes are reusable catalysts	4	5
15	True / False	Enzyme denaturation at high temperature	4	5
16	Multiple choice	ATP vs. DNA roles	4	5
17	Matching	Photosynthesis part → location/output	4	7
18	Multiple choice	Fermentation in sprinting muscles	4	6
19	Multiple choice	Photosynthesis — where a plant's mass comes from	4	7
20	Multiple answer	Cellular respiration — true statements	4	6

Objective totals: Obj 1 = 3 · Obj 2 = 6 · Obj 3 = 4 · Obj 4 = 7 → 20 items (ungraded; mirrors the 100-point midterm's emphasis). Quantitative items: 2 (Q4 pH pocket; Q10 SA:V pocket).

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Questions, key, and feedback (feedback releases after you submit)

Objective 1 — The Process of Science & Characteristics of Life (Week 1)

Q1 (MC). A gardener argues a dry, dormant seed is not alive because it shows almost no visible activity, while insisting a flickering candle flame is alive because it moves and grows. Applying the characteristics of life correctly, which is true?
- A. The seed is alive (it is cellular and carries DNA); the flame is not alive (no cells, no DNA, no homeostasis) ✅
- B. Both are alive, because both grow
- C. Neither is alive, because neither moves on its own
- D. The flame is alive but the seed is not, because activity is the test for life
Feedback: A dormant seed is alive — it is made of cells, carries DNA, and resumes the full set of life processes when conditions allow. A flame fails the checklist (no cells/DNA/homeostasis). "Activity" or "movement" is never the test — life is the whole set of characteristics.

Q2 (MC). A student lists biological structures from smallest to largest. Which sequence is in the correct order of the levels of organization?
- A. cell → molecule → atom → tissue → organ
- B. atom → molecule → cell → tissue → organ ✅
- C. molecule → atom → organ → tissue → cell
- D. organ → tissue → cell → molecule → atom
Feedback: The levels nest from small to large: atom → molecule → cell → tissue → organ (→ organ system → organism → population → ecosystem). Atoms build molecules, molecules build cells, and so on up. (D is the right items in reverse order.)

Q3 (MC). A researcher tests whether a new plant food increases leaf count. One group of basil plants gets the plant food; an identical group gets none. Everything else is held constant, and after three weeks the researcher counts each plant's leaves. The dependent variable is —
- A. whether a plant received the plant food
- B. the number of leaves measured after three weeks ✅
- C. the type of soil used for every plant
- D. the amount of sunlight, kept the same for all
Feedback: The dependent variable is the outcome you measure — the leaf count. (A is the independent variable, what's changed; C and D are controlled variables, kept the same.) "The result Depends on the treatment."

Objective 2 — The Chemistry of Life & Macromolecules (Weeks 2–3)

Q4 (MC). Four household liquids are tested and give these pH readings: vinegar = 3, black coffee = 5, pure water = 7, and a baking-soda solution = 9. Remembering that each pH unit is a 10-fold change in H⁺ concentration, which liquid is the most acidic?
- A. vinegar (pH 3) ✅
- B. black coffee (pH 5)
- C. pure water (pH 7)
- D. baking-soda solution (pH 9)
Feedback: Lower pH = more acidic, so the lowest reading is the most acidic — vinegar at pH 3. (Quantitative item — pre-verified: min{3,5,7,9} = 3; the baking-soda solution at pH 9 is the most basic, not acidic.)

Q5 (MC). In table salt (NaCl), a sodium atom gives up an electron to a chlorine atom, producing two oppositely charged ions that attract each other. This kind of bond, formed by the transfer of an electron, is a(n) —
- A. covalent bond
- B. hydrogen bond
- C. ionic bond ✅
- D. peptide bond
Feedback: When electrons are transferred (not shared), the result is charged ions that attract — an ionic bond. (Covalent bonds share electrons — the classic mix-up; hydrogen bonds are weak inter-molecular attractions; peptide bonds link amino acids.)

Q6 (Matching). Match each life-supporting property of water to the everyday observation it explains.
| Property of water | Correct observation |
|---|---|
| Cohesion / surface tension | An insect can stand on the surface of a pond |
| High specific heat | Lakes resist sudden temperature swings, moderating climate |
| Ice floats (less dense as a solid) | A frozen pond forms ice on top, insulating fish below |
| Universal solvent | Many substances dissolve in water inside cells and blood |
Feedback: Water's polarity and hydrogen bonding give it these life-giving traits: cohesion (surface tension), high specific heat (temperature buffering), floating ice (insulating lakes), and being a great solvent. Each makes life on Earth possible in a specific way.

Q7 (MC). Glucose can be linked into starch (an energy-storage polysaccharide) or into cellulose (a rigid structural fiber in plant cell walls). This is the clearest illustration that, for macromolecules —
- A. all carbohydrates are simple sugars that taste sweet
- B. the way monomers are arranged determines a molecule's structure and therefore its function ✅
- C. lipids and carbohydrates are the same class of molecule
- D. cellulose is broken down for quick energy just like starch
Feedback: The same monomer (glucose), arranged differently, yields starch (storage) or cellulose (structure) — the spine of the course: structure determines function. (A and D are the "all carbs are sugar/fuel" misconception — cellulose is indigestible structural fiber.)

Q8 (MC). DNA and RNA store and transmit genetic information. The monomer (building block) that makes up these nucleic acids is the —
- A. amino acid
- B. nucleotide ✅
- C. fatty acid
- D. monosaccharide
Feedback: Nucleic acids (DNA, RNA) are polymers of nucleotides. (Amino acids build proteins; monosaccharides build carbohydrates; fatty acids are part of many lipids.) Keep each macromolecule paired with its monomer.

Q9 (Multiple answer — select all that apply). Select all of the following statements about the four classes of biological macromolecules that are true.
- A. Carbohydrates serve in both energy (starch) and structure (cellulose) ✅
- B. Lipids are NOT polymers and are important for energy storage and membranes ✅
- C. Proteins are polymers of nucleotides
- D. Changing a single amino acid can alter a protein's shape and function ✅
- E. Hydrolysis uses water to break polymers into monomers ✅
Feedback: Carbohydrates do double duty (A); lipids are not polymers (B); one wrong amino acid can change a protein (D — think sickle-cell); and hydrolysis adds water to break bonds (E). C is false — proteins are polymers of amino acids, not nucleotides.

Objective 3 — Cell Structure, Membranes & Transport (Week 4)

Q10 (MC). Four model cells are cubes with side lengths of 1, 2, 3, and 4 units. Using surface area = 6s² and volume = s³ (so SA:V = 6/s), which cube has the highest surface-area-to-volume ratio?
- A. the cube with side 1 (ratio 6 : 1) ✅
- B. the cube with side 2 (ratio 3 : 1)
- C. the cube with side 3 (ratio 2 : 1)
- D. the cube with side 4 (ratio 1.5 : 1)
Feedback: SA:V = 6/s, so the smallest cube has the highest ratio: side 1 → 6 : 1. (Quantitative item — pre-verified: 6/1 = 6, 6/2 = 3, 6/3 = 2, 6/4 = 1.5.) Smaller cells exchange materials more efficiently — why cells stay small.

Q11 (MC). A microbiologist distinguishes a bacterial (prokaryotic) cell from an animal (eukaryotic) cell. The single most defining difference is that —
- A. only eukaryotic cells have a cell membrane
- B. prokaryotic cells lack a membrane-bound nucleus, whereas eukaryotic cells have one ✅
- C. prokaryotic cells are always larger than eukaryotic cells
- D. only prokaryotic cells contain DNA
Feedback: The defining split is the nucleus: prokaryotes have no membrane-bound nucleus (their DNA floats free); eukaryotes do. (All cells have a membrane and DNA — A and D are false; prokaryotes are generally smaller, not larger.)

Q12 (Matching). Match each membrane-transport term to its correct description.
| Transport term | Correct description |
|---|---|
| Diffusion | Solutes spread from high to low concentration; no ATP needed |
| Osmosis | Movement of WATER across a membrane down its gradient |
| Active transport | Moves a substance AGAINST its gradient; requires ATP |
| Phospholipid bilayer | The fluid-mosaic structural basis of the cell membrane |
Feedback: Passive transport needs no energy (diffusion of solutes; osmosis of water); active transport spends ATP to push against a gradient. The membrane itself is a phospholipid bilayer (the fluid-mosaic model). Remember: osmosis moves water, not solute.

Q13 (True / False). Plant cells do not contain mitochondria, because they make their own food by photosynthesis and therefore have no need for cellular respiration.
- True
- False ✅
Feedback: False. Plant cells have both chloroplasts and mitochondria — they make sugar by photosynthesis and burn it for ATP by cellular respiration, around the clock. "Plants don't do respiration" is a classic misconception.

Objective 4 — Energy, Enzymes, Respiration & Photosynthesis (Weeks 5–7)

Q14 (MC). A single enzyme molecule in your saliva can break down thousands of starch molecules, one after another. This is because enzymes —
- A. are consumed and destroyed by each reaction they catalyze
- B. are reusable catalysts that are not permanently changed by the reaction ✅
- C. supply the energy that powers the reaction
- D. work only once and then must be rebuilt from amino acids
Feedback: Enzymes are reusable catalysts — they are not used up, so one molecule can act again and again. (A and D are the "used up" myth; C is wrong — enzymes lower activation energy, they don't supply energy.)

Q15 (True / False). At very high temperatures an enzyme can denature, losing its specific shape, which causes its reaction rate to drop sharply.
- True ✅
- False
Feedback: True. Past its optimum, heat denatures an enzyme — its shape unfolds, the active site no longer fits the substrate, and the rate crashes. Enzyme rate rises to an optimum, then falls; "more heat is always better" is false.

Q16 (MC). A student confuses two molecules. Which correctly states the role of ATP versus DNA?
- A. ATP stores genetic information; DNA is the cell's energy currency
- B. ATP is the cell's immediate energy currency; DNA stores genetic information ✅
- C. Both ATP and DNA are enzymes that lower activation energy
- D. ATP and DNA are two names for the same molecule
Feedback: ATP = the cell's energy currency; DNA = the molecule that stores genetic information. (They are different molecules with different jobs — A reverses them; C and D are simply wrong.)

Q17 (Matching). Match each part of photosynthesis to its correct location or output.
| Photosynthesis part | Correct location / output |
|---|---|
| Light-dependent reactions | In the thylakoid membranes; split water and release O₂; make ATP + NADPH |
| Calvin cycle (light-independent) | In the stroma; fixes CO₂ into sugar using ATP and NADPH |
| Chlorophyll | The pigment in chloroplasts that absorbs light energy |
Feedback: The light reactions (in the thylakoids) split water, release O₂, and make ATP + NADPH; the Calvin cycle (in the stroma) uses those to build sugar from CO₂. Chlorophyll is the light-absorbing pigment. The Calvin cycle needs the light reactions' products, so it can't run for long in the dark.

Q18 (MC). During an all-out sprint, a runner's muscles run low on oxygen and begin to burn and fatigue. Which process lets the muscle cells keep making a little ATP without oxygen, and what byproduct builds up?
- A. Aerobic respiration; carbon dioxide
- B. The Calvin cycle; glucose
- C. Lactic-acid fermentation; lactic acid ✅
- D. Photosynthesis; oxygen
Feedback: Without enough O₂, muscle cells switch to lactic-acid fermentation, which keeps a small amount of ATP coming and produces lactic acid (the burn). (Aerobic respiration needs O₂; the Calvin cycle and photosynthesis are plant sugar-building processes.)

Q19 (MC). A skeptic claims a tree gets nearly all of its added mass from the soil. Using photosynthesis, the most accurate correction is that most of a plant's mass comes from —
- A. minerals pulled up from the soil
- B. carbon atoms captured from CO₂ in the air (plus water) ✅
- C. sunlight, which is converted directly into matter
- D. oxygen absorbed through the leaves
Feedback: A tree's mass comes mostly from carbon captured out of the air as CO₂ (combined with water), not from soil. (Light provides energy, not matter — C; soil minerals are needed only in tiny amounts — A.) "A tree is built largely from thin air."

Q20 (Multiple answer — select all that apply). Select all of the following statements about cellular respiration that are true.
- A. The overall process converts glucose and O₂ into CO₂, water, and ATP ✅
- B. Glycolysis occurs in the cytoplasm and does not by itself require oxygen ✅
- C. Cellular respiration is just another word for breathing air in and out
- D. The electron transport chain yields far more ATP than glycolysis does ✅
- E. Both plants and animals carry out cellular respiration ✅
Feedback: The big equation (A), glycolysis starting in the cytoplasm without O₂ (B), the ETC making the most ATP (D), and both plants and animals respiring (E) are all true. C is false — respiration is a cellular chemical process, not the same as breathing.

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Answer key (quick reference)

Q	Answer	Q	Answer
1	A (seed alive; flame not)	11	B (prokaryotes lack a nucleus)
2	B (atom→molecule→cell→tissue→organ)	12	Diffusion→solutes, no ATP / Osmosis→water / Active→against gradient, ATP / Bilayer→fluid mosaic
3	B (leaf count measured)	13	False (plant cells have mitochondria)
4	A (vinegar, pH 3 — most acidic)	14	B (reusable catalyst)
5	C (ionic — electron transfer)	15	True (it denatures)
6	Cohesion→strider / High specific heat→climate / Ice floats→insulates fish / Solvent→dissolves	16	B (ATP currency; DNA information)
7	B (arrangement → structure → function)	17	Light reactions→thylakoid, O₂ / Calvin→stroma, CO₂ / Chlorophyll→pigment
8	B (nucleotide)	18	C (lactic-acid fermentation; lactic acid)
9	A, B, D, E	19	B (carbon from CO₂ in the air)
10	A (side 1 → 6 : 1)	20	A, B, D, E

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Quality gate (H5 — self-checked)

• Mirror check: 20 items, coverage Obj 1 = 3 · Obj 2 = 6 · Obj 3 = 4 · Obj 4 = 7 — matches the midterm blueprint's emphasis and item-type mix (13 multiple-choice + 3 matching + 2 multiple-answer + 2 true/false).
• Single-answer integrity: every multiple-choice and true/false item (Q1–Q5, Q7, Q8, Q10, Q11, Q13–Q16, Q18, Q19) has exactly one correct option; the three matching items (Q6, Q12, Q17) pair one-to-one; the two multiple-answer items (Q9, Q20) key A, B, D, E (C must be left unselected).
• Quantitative gate: PASS. Both quantitative items were re-derived in a Python check: Q4 the most acidic of {3, 5, 7, 9} is pH 3 (lowest pH); Q10 SA:V = 6/s is highest at the smallest cube, side 1 → 6 : 1. Numbers are the pre-verified pH and SA:V values from the course's quantitative pockets (Weeks 2 and 4).
• Factual accuracy: real processes (glycolysis, fermentation, the Calvin cycle, photosynthesis) referenced factually; nothing falls outside the Weeks 1–7 course definitions.
• QTI parse confirmation: O-practice-exam-week-08-qti.xml parses as imsqti_xmlv1p2 with 20 items; every single-answer respcondition sets SCORE = 100 on exactly one option. (In Canvas the placement makes it ungraded with feedback on; the engine still scores attempts so students see what they missed.)
• Integrity vs. the live exam: 0 items are shared with L-midterm-week-08.md — verified by full stem comparison. Where a concept slot overlaps the midterm, this form uses a different scenario (e.g., the midterm's pH item asks "how many times more acidic is pH 4 vs pH 7" → 1000×; here Q4 asks "which of four readings is most acidic" → pH 3; the midterm's SA:V item computes the ratio for side 2 → 3 : 1; here Q10 asks which of four cubes has the highest ratio → side 1).

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Item-bank & coverage note

All 20 items are fresh variants assembled from the Week 1–7 item banks, preferring items not used on the live midterm and authoring fresh scenarios where a concept overlaps. Tagged course=BIOL101 · form=practice-midterm · weeks=1–7 · objectives=1–4 and deposited back into the banks for future per-term ($39) regenerations. Each term's update regenerates fresh practice variants alongside the midterm and continues to share none of the live items.

Canvas placement block

canvas_object             = Quizzes::Quiz
title                     = "Midterm Practice Exam (ungraded)"
assignment_group          = "Practice exercises"
points_possible           = 0
grading_type              = not_graded
allowed_attempts          = unlimited
show_feedback             = true        # released after submission
available_from_offset_days = -3        # opens 3 days before the exam window
due_offset_days           = 6         # on or before the exam due date
published                 = true
shuffle_answers           = true
provenance                = "~ Prof. Castellano's edition · Fall 2026 · built with thecoursemaker.com"