Biology (Grades 9–10) Midterm — Semester 1, Form A
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Free printable Biology midterm (Grades 9–10): 15 multiple-choice questions plus 1 written response covering Biochemistry, Cells & Cell Transport, Photosynthesis & Cellular Respiration. Answer key included — customize it in the Midterm Maker.
Biology (Grades 9–10) Midterm — Semester 1, Form A
Name: Date: Period:
Directions: Read each question carefully and choose the best answer. Answer the written response in complete sentences.
Covers: Biochemistry · Cells & Cell Transport · Photosynthesis & Cellular Respiration
Part 1: Multiple Choice
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Why does an enzyme stop working at very high temperatures?
- A. It gains extra amino acids
- B. Its shape changes, so the active site no longer fits the substrate
- C. Its substrate becomes an enzyme
- D. It turns into a carbohydrate
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Water molecules stick to one another mainly because of which type of attraction?
- A. Peptide bonds between water molecules
- B. Ionic bonds between water molecules
- C. Attraction between nonpolar molecules
- D. Hydrogen bonds between polar molecules
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Simple carbohydrates are made of which elements?
- A. Carbon, oxygen, and phosphorus
- B. Carbon, hydrogen, and nitrogen
- C. Carbon, hydrogen, and oxygen
- D. Nitrogen, oxygen, and sulfur
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What are the monomers (building blocks) of proteins?
- A. Nucleotides
- B. Amino acids
- C. Monosaccharides
- D. Fatty acids
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A solution with pH 3 has how many times more hydrogen ions than a solution with pH 5?
- A. 1,000
- B. 2
- C. 20
- D. 100
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A white blood cell surrounds and takes in a bacterium by folding its membrane around it. What is this process called?
- A. Exocytosis
- B. Endocytosis
- C. Diffusion
- D. Osmosis
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Which organelle modifies, sorts, and packages proteins for transport?
- A. Golgi apparatus
- B. Nucleolus
- C. Lysosome
- D. Mitochondrion
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Which process uses energy to move substances against their concentration gradient?
- A. Simple diffusion
- B. Active transport
- C. Facilitated diffusion
- D. Osmosis
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What is osmosis?
- A. Engulfing of large particles
- B. Pumping of glucose against its gradient
- C. Movement of salt using ATP
- D. Diffusion of water across a selectively permeable membrane
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An animal cell is placed in a solution saltier than its cytoplasm. What happens?
- A. Salt leaves the cell and it bursts
- B. Nothing changes in the cell
- C. Water leaves the cell and it shrinks
- D. Water enters the cell and it swells
-
What are the reactants of photosynthesis?
- A. Oxygen and water
- B. Carbon dioxide and water
- C. Glucose and oxygen
- D. Glucose and carbon dioxide
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Where in the chloroplast does the Calvin cycle take place?
- A. Thylakoid membrane
- B. Stroma
- C. Cytoplasm
- D. Mitochondrial matrix
-
When oxygen is scarce, human muscle cells carry out fermentation that produces what?
- A. Oxygen
- B. Ethanol
- C. Lactic acid
- D. Glucose
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Which stage of aerobic cellular respiration produces the most ATP?
- A. Fermentation
- B. Glycolysis
- C. Krebs cycle
- D. Electron transport chain
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Which are the products of aerobic cellular respiration?
- A. Glucose and carbon dioxide
- B. Glucose and oxygen
- C. Oxygen and water
- D. Carbon dioxide, water, and ATP
Part 2: Written Response
- Explain how an enzyme's structure determines its function. Then predict and explain how changes in temperature and pH could affect an enzyme's activity.
Answer Key — Biology (Grades 9–10) Midterm — Semester 1, Form A
- B — Its shape changes, so the active site no longer fits the substrate Heat denatures proteins by disrupting their folded shape.
- D — Hydrogen bonds between polar molecules Water's polarity allows hydrogen bonding, causing cohesion.
- C — Carbon, hydrogen, and oxygen Sugars such as glucose (C₆H₁₂O₆) contain only C, H, and O.
- B — Amino acids Proteins are chains of amino acids joined by peptide bonds.
- D — 100 Each pH unit is a tenfold change: 10 × 10 = 100.
- B — Endocytosis Endocytosis brings large materials in using membrane vesicles.
- A — Golgi apparatus The Golgi processes proteins received from the endoplasmic reticulum.
- B — Active transport Active transport requires ATP to move from low to high concentration.
- D — Diffusion of water across a selectively permeable membrane Osmosis is specifically the passive movement of water.
- C — Water leaves the cell and it shrinks In a hypertonic solution, water moves out by osmosis.
- B — Carbon dioxide and water 6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂.
- B — Stroma The Calvin cycle uses ATP and NADPH in the stroma to fix carbon.
- C — Lactic acid Lactic acid fermentation regenerates NAD⁺ so glycolysis can continue.
- D — Electron transport chain The electron transport chain drives ATP synthase to make most ATP.
- D — Carbon dioxide, water, and ATP C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP.
Written Response — Look-Fors
- Enzymes are proteins with a specific active site that binds a substrate; lowers activation energy; extreme temperature/pH denatures the enzyme, changing shape so substrate no longer fits; mentions an optimal range.