Biological Science, 7th Edition (Freeman) - 2025/2026 Study
Guide
Unit 1: The Chemical and Cellular Foundation of Life
1. What are the four major classes of biological macromolecules, and what is a
primary function of each?
ANSWER ✓ The four major classes are: 1) Carbohydrates - for energy storage and
structural support; 2) Lipids - for long-term energy storage, membrane structure, and
signaling; 3) Proteins - for catalyzing reactions (enzymes), structure, transport, and
defense; 4) Nucleic Acids - for storing and transmitting genetic information.
2. How does the structure of the plasma membrane relate to its function?
ANSWER ✓ The fluid mosaic model describes the membrane as a phospholipid bilayer
with embedded proteins. This structure provides a selectively permeable barrier,
allowing the cell to control the passage of substances, while the proteins facilitate
transport, signaling, and recognition.
3. What is the fundamental difference between prokaryotic and eukaryotic cells?
ANSWER ✓ The primary difference is that eukaryotic cells have a membrane-bound
nucleus and other membrane-bound organelles, while prokaryotic cells do not.
4. Describe the endosymbiotic theory and the evidence that supports it.
ANSWER ✓ The endosymbiotic theory proposes that mitochondria and chloroplasts
evolved from free-living prokaryotes that were engulfed by a larger host cell. Evidence
includes: their own circular DNA, double membranes, and the ability to replicate
independently of the cell cycle.
5. What is the role of ATP in cellular metabolism?
ANSWER ✓ ATP (Adenosine Triphosphate) is the primary energy currency of the cell. It
stores chemical energy in its phosphate bonds, which is released through hydrolysis to
drive endergonic cellular processes.
6. How do enzymes catalyze biochemical reactions?
ANSWER ✓ Enzymes lower the activation energy of a reaction, thereby speeding up the
rate at which the reaction occurs. They do this by binding to substrates in their active
site, stabilizing the transition state.
, 7. What are the net inputs and outputs of glycolysis?
ANSWER ✓ Net Inputs: 1 Glucose, 2 ATP, 2 NAD+. Net Outputs: 2 Pyruvate, 4 ATP (net
gain of 2 ATP), 2 NADH.
8. Where in the cell does the Citric Acid (Krebs) Cycle occur, and what are its main
products?
ANSWER ✓ It occurs in the mitochondrial matrix. Its main products per acetyl-CoA are: 3
NADH, 1 FADH₂, 1 ATP (or GTP), and 2 CO₂.
9. Describe the process of chemiosmosis in oxidative phosphorylation.
ANSWER ✓ The electron transport chain pumps protons (H+) from the mitochondrial
matrix to the intermembrane space, creating an electrochemical gradient. The potential
energy in this gradient drives protons back into the matrix through ATP synthase, which
uses the flow to phosphorylate ADP into ATP.
10. What is the primary purpose of cellular respiration?
ANSWER ✓ To break down organic molecules (like glucose) to produce ATP, which
powers cellular work.
11. What are the two stages of photosynthesis, and where does each occur in the
chloroplast?
ANSWER ✓ 1) The Light-Dependent Reactions occur in the thylakoid membranes and
convert light energy into chemical energy (ATP and NADPH). 2) The Light-Independent
Reactions (Calvin Cycle) occur in the stroma and use that chemical energy to fix carbon
dioxide into sugars.
12. What is the primary function of the Calvin Cycle?
ANSWER ✓ To fix atmospheric carbon dioxide (CO₂) into organic molecules, specifically
to produce glyceraldehyde-3-phosphate (G3P), which can be used to make glucose and
other carbohydrates.
13. How do mitotic cell division and meiotic cell division differ in their outcomes?
ANSWER ✓ Mitosis produces two genetically identical diploid daughter cells for growth
and repair. Meiosis produces four genetically non-identical haploid gametes (sperm or
egg cells) for sexual reproduction.
14. What are the key checkpoints in the cell cycle and what is their purpose?
ANSWER ✓ The G1 checkpoint ensures the cell is large enough and the environment is
favorable for division. The G2 checkpoint checks for complete DNA replication and any
DNA damage. The M spindle-assembly checkpoint ensures all chromosomes are
properly attached to the spindle.
Guide
Unit 1: The Chemical and Cellular Foundation of Life
1. What are the four major classes of biological macromolecules, and what is a
primary function of each?
ANSWER ✓ The four major classes are: 1) Carbohydrates - for energy storage and
structural support; 2) Lipids - for long-term energy storage, membrane structure, and
signaling; 3) Proteins - for catalyzing reactions (enzymes), structure, transport, and
defense; 4) Nucleic Acids - for storing and transmitting genetic information.
2. How does the structure of the plasma membrane relate to its function?
ANSWER ✓ The fluid mosaic model describes the membrane as a phospholipid bilayer
with embedded proteins. This structure provides a selectively permeable barrier,
allowing the cell to control the passage of substances, while the proteins facilitate
transport, signaling, and recognition.
3. What is the fundamental difference between prokaryotic and eukaryotic cells?
ANSWER ✓ The primary difference is that eukaryotic cells have a membrane-bound
nucleus and other membrane-bound organelles, while prokaryotic cells do not.
4. Describe the endosymbiotic theory and the evidence that supports it.
ANSWER ✓ The endosymbiotic theory proposes that mitochondria and chloroplasts
evolved from free-living prokaryotes that were engulfed by a larger host cell. Evidence
includes: their own circular DNA, double membranes, and the ability to replicate
independently of the cell cycle.
5. What is the role of ATP in cellular metabolism?
ANSWER ✓ ATP (Adenosine Triphosphate) is the primary energy currency of the cell. It
stores chemical energy in its phosphate bonds, which is released through hydrolysis to
drive endergonic cellular processes.
6. How do enzymes catalyze biochemical reactions?
ANSWER ✓ Enzymes lower the activation energy of a reaction, thereby speeding up the
rate at which the reaction occurs. They do this by binding to substrates in their active
site, stabilizing the transition state.
, 7. What are the net inputs and outputs of glycolysis?
ANSWER ✓ Net Inputs: 1 Glucose, 2 ATP, 2 NAD+. Net Outputs: 2 Pyruvate, 4 ATP (net
gain of 2 ATP), 2 NADH.
8. Where in the cell does the Citric Acid (Krebs) Cycle occur, and what are its main
products?
ANSWER ✓ It occurs in the mitochondrial matrix. Its main products per acetyl-CoA are: 3
NADH, 1 FADH₂, 1 ATP (or GTP), and 2 CO₂.
9. Describe the process of chemiosmosis in oxidative phosphorylation.
ANSWER ✓ The electron transport chain pumps protons (H+) from the mitochondrial
matrix to the intermembrane space, creating an electrochemical gradient. The potential
energy in this gradient drives protons back into the matrix through ATP synthase, which
uses the flow to phosphorylate ADP into ATP.
10. What is the primary purpose of cellular respiration?
ANSWER ✓ To break down organic molecules (like glucose) to produce ATP, which
powers cellular work.
11. What are the two stages of photosynthesis, and where does each occur in the
chloroplast?
ANSWER ✓ 1) The Light-Dependent Reactions occur in the thylakoid membranes and
convert light energy into chemical energy (ATP and NADPH). 2) The Light-Independent
Reactions (Calvin Cycle) occur in the stroma and use that chemical energy to fix carbon
dioxide into sugars.
12. What is the primary function of the Calvin Cycle?
ANSWER ✓ To fix atmospheric carbon dioxide (CO₂) into organic molecules, specifically
to produce glyceraldehyde-3-phosphate (G3P), which can be used to make glucose and
other carbohydrates.
13. How do mitotic cell division and meiotic cell division differ in their outcomes?
ANSWER ✓ Mitosis produces two genetically identical diploid daughter cells for growth
and repair. Meiosis produces four genetically non-identical haploid gametes (sperm or
egg cells) for sexual reproduction.
14. What are the key checkpoints in the cell cycle and what is their purpose?
ANSWER ✓ The G1 checkpoint ensures the cell is large enough and the environment is
favorable for division. The G2 checkpoint checks for complete DNA replication and any
DNA damage. The M spindle-assembly checkpoint ensures all chromosomes are
properly attached to the spindle.
