Cell Biology — Complete Study Notes & Exam
Review
A concise, exam-focused study guide covering cell structure, transport, enzymes, respiration, photosynthesis, cell
division, DNA and protein synthesis.
1. Introduction to Cell Biology
Cell biology is the study of cells, their structures, functions, and interactions. The cell is the basic structural and
functional unit of life.
Cell theory: All living organisms are made of one or more cells; the cell is the basic unit of life; cells arise from
pre-existing cells; cells contain hereditary information passed to daughter cells.
2. Types of Cells
Prokaryotic: generally smaller and simpler; no membrane-bound nucleus; DNA is in a nucleoid; usually circular
chromosome; no membrane-bound mitochondria or chloroplasts. Examples include bacteria and archaea.
Eukaryotic: have a membrane-bound nucleus and membrane-bound organelles. Examples include animal, plant,
fungal and protist cells.
3. Prokaryotic vs. Eukaryotic Cells
Prokaryotic: nucleus absent, DNA usually circular, membrane-bound organelles absent, generally smaller.
Eukaryotic: nucleus present, linear chromosomes, membrane-bound organelles present, generally larger.
4. Cell Organelles and Functions
Nucleus: stores most genetic information and regulates many cellular activities.
Nucleolus: produces and assembles ribosomal components.
Ribosomes: protein synthesis.
Mitochondria: major sites of aerobic cellular respiration and ATP production.
Chloroplasts: photosynthesis in plants and many algae; contain chlorophyll.
Rough ER: protein synthesis/processing and transport.
Smooth ER: lipid synthesis, detoxification and calcium storage in specialized cells.
Golgi apparatus: modifies, sorts and packages proteins and lipids.
Lysosomes: intracellular digestion and recycling.
Vacuoles: storage; plant central vacuole helps maintain pressure.
Cell membrane: selectively permeable barrier.
Cell wall: support and shape in plants; mainly cellulose.
Cytoskeleton: shape, transport, movement and cell division.
5. Plant vs. Animal Cells
Plant cells have a cellulose cell wall, chloroplasts and usually a large central vacuole. Animal cells lack chloroplasts
and a cellulose cell wall and commonly contain lysosomes.
6. Cell Membrane Structure
Cell Biology Study Notes • Page 1
, The fluid mosaic model describes a phospholipid bilayer with embedded proteins. Phospholipids have hydrophilic
heads and hydrophobic tails. Membrane proteins can function in transport, signaling, recognition, adhesion and
enzyme activity.
7. Movement Across the Membrane
Diffusion: net movement from higher to lower concentration.
Osmosis: net movement of water across a selectively permeable membrane from higher water potential to lower
water potential.
Facilitated diffusion: passive movement through channel or carrier proteins.
Active transport: movement against a concentration gradient using energy, commonly ATP.
Endocytosis: uptake into the cell in vesicles.
Exocytosis: vesicles fuse with the membrane to release contents outside.
8. Enzymes
Enzymes are biological catalysts that increase reaction rates without being permanently consumed. Most are
proteins. The active site is where substrate binding and reaction occur. Activity can be affected by temperature, pH,
substrate concentration, enzyme concentration and inhibitors. Very high temperatures can denature many enzymes.
9. Cellular Respiration
A simplified equation is: Glucose + oxygen → carbon dioxide + water + energy. Major stages include glycolysis,
pyruvate oxidation, the citric acid cycle and oxidative phosphorylation. Glycolysis occurs in the cytoplasm and
produces pyruvate, ATP and NADH. In eukaryotes, later stages occur in mitochondria.
10. Photosynthesis
A simplified equation is: Carbon dioxide + water + light energy → glucose + oxygen. Light-dependent reactions
occur in thylakoid membranes and produce ATP, NADPH and oxygen. The Calvin cycle occurs in the stroma and
uses carbon dioxide, ATP and NADPH to help produce carbohydrates.
11. Cell Cycle
Interphase includes G1, S and G2. G1 is growth and normal activity; S is DNA replication; G2 is preparation for
division. The M phase includes nuclear division and usually cytokinesis.
12. Mitosis
Stages: Prophase — chromosomes condense and spindle forms; Metaphase — chromosomes align near the cell
middle; Anaphase — sister chromatids separate; Telophase — new nuclei form; Cytokinesis — cytoplasm divides.
Mitosis usually produces two genetically similar daughter cells.
13. Meiosis
Meiosis has two divisions, meiosis I and meiosis II, and produces haploid cells. Genetic variation results from
crossing over and independent assortment, with additional variation from random fertilization in sexual reproduction.
The typical result is four haploid cells.
14. Mitosis vs. Meiosis
Mitosis: one division, usually two daughter cells, chromosome number maintained, usually genetically similar,
growth/repair. Meiosis: two divisions, typically four haploid cells, chromosome number reduced, genetically varied,
Cell Biology Study Notes • Page 2
Review
A concise, exam-focused study guide covering cell structure, transport, enzymes, respiration, photosynthesis, cell
division, DNA and protein synthesis.
1. Introduction to Cell Biology
Cell biology is the study of cells, their structures, functions, and interactions. The cell is the basic structural and
functional unit of life.
Cell theory: All living organisms are made of one or more cells; the cell is the basic unit of life; cells arise from
pre-existing cells; cells contain hereditary information passed to daughter cells.
2. Types of Cells
Prokaryotic: generally smaller and simpler; no membrane-bound nucleus; DNA is in a nucleoid; usually circular
chromosome; no membrane-bound mitochondria or chloroplasts. Examples include bacteria and archaea.
Eukaryotic: have a membrane-bound nucleus and membrane-bound organelles. Examples include animal, plant,
fungal and protist cells.
3. Prokaryotic vs. Eukaryotic Cells
Prokaryotic: nucleus absent, DNA usually circular, membrane-bound organelles absent, generally smaller.
Eukaryotic: nucleus present, linear chromosomes, membrane-bound organelles present, generally larger.
4. Cell Organelles and Functions
Nucleus: stores most genetic information and regulates many cellular activities.
Nucleolus: produces and assembles ribosomal components.
Ribosomes: protein synthesis.
Mitochondria: major sites of aerobic cellular respiration and ATP production.
Chloroplasts: photosynthesis in plants and many algae; contain chlorophyll.
Rough ER: protein synthesis/processing and transport.
Smooth ER: lipid synthesis, detoxification and calcium storage in specialized cells.
Golgi apparatus: modifies, sorts and packages proteins and lipids.
Lysosomes: intracellular digestion and recycling.
Vacuoles: storage; plant central vacuole helps maintain pressure.
Cell membrane: selectively permeable barrier.
Cell wall: support and shape in plants; mainly cellulose.
Cytoskeleton: shape, transport, movement and cell division.
5. Plant vs. Animal Cells
Plant cells have a cellulose cell wall, chloroplasts and usually a large central vacuole. Animal cells lack chloroplasts
and a cellulose cell wall and commonly contain lysosomes.
6. Cell Membrane Structure
Cell Biology Study Notes • Page 1
, The fluid mosaic model describes a phospholipid bilayer with embedded proteins. Phospholipids have hydrophilic
heads and hydrophobic tails. Membrane proteins can function in transport, signaling, recognition, adhesion and
enzyme activity.
7. Movement Across the Membrane
Diffusion: net movement from higher to lower concentration.
Osmosis: net movement of water across a selectively permeable membrane from higher water potential to lower
water potential.
Facilitated diffusion: passive movement through channel or carrier proteins.
Active transport: movement against a concentration gradient using energy, commonly ATP.
Endocytosis: uptake into the cell in vesicles.
Exocytosis: vesicles fuse with the membrane to release contents outside.
8. Enzymes
Enzymes are biological catalysts that increase reaction rates without being permanently consumed. Most are
proteins. The active site is where substrate binding and reaction occur. Activity can be affected by temperature, pH,
substrate concentration, enzyme concentration and inhibitors. Very high temperatures can denature many enzymes.
9. Cellular Respiration
A simplified equation is: Glucose + oxygen → carbon dioxide + water + energy. Major stages include glycolysis,
pyruvate oxidation, the citric acid cycle and oxidative phosphorylation. Glycolysis occurs in the cytoplasm and
produces pyruvate, ATP and NADH. In eukaryotes, later stages occur in mitochondria.
10. Photosynthesis
A simplified equation is: Carbon dioxide + water + light energy → glucose + oxygen. Light-dependent reactions
occur in thylakoid membranes and produce ATP, NADPH and oxygen. The Calvin cycle occurs in the stroma and
uses carbon dioxide, ATP and NADPH to help produce carbohydrates.
11. Cell Cycle
Interphase includes G1, S and G2. G1 is growth and normal activity; S is DNA replication; G2 is preparation for
division. The M phase includes nuclear division and usually cytokinesis.
12. Mitosis
Stages: Prophase — chromosomes condense and spindle forms; Metaphase — chromosomes align near the cell
middle; Anaphase — sister chromatids separate; Telophase — new nuclei form; Cytokinesis — cytoplasm divides.
Mitosis usually produces two genetically similar daughter cells.
13. Meiosis
Meiosis has two divisions, meiosis I and meiosis II, and produces haploid cells. Genetic variation results from
crossing over and independent assortment, with additional variation from random fertilization in sexual reproduction.
The typical result is four haploid cells.
14. Mitosis vs. Meiosis
Mitosis: one division, usually two daughter cells, chromosome number maintained, usually genetically similar,
growth/repair. Meiosis: two divisions, typically four haploid cells, chromosome number reduced, genetically varied,
Cell Biology Study Notes • Page 2
