AP Biology · Unit 2
Cells
In short
Unit 2: Cells in AP Biology covers 10 topics: Cell Structure and Function, Cell Size, Plasma Membrane, Membrane Permeability and 6 more. Open each one for what you need to know, a self-check list and how it is tested on the exam.
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What is in Unit 2: Cells?
Unit 2: Cells
2.1 Cell Structure and Function
- I can describe the composition of ribosomes and explain their role in synthesizing proteins according to mRNA sequences.
- I can identify the components of the endomembrane system and describe how they work together to modify, package, and transport materials.
- I can explain the functions of the rough and smooth endoplasmic reticulum, including their roles in protein synthesis, compartmentalization, detoxification, and lipid synthesis.
- I can describe the structure of the Golgi complex and its functions in folding, chemically modifying, and packaging newly synthesized cellular products.
- I can explain how the double membrane structure of mitochondria, including the highly convoluted inner membrane, enables efficient ATP synthesis.
- I can describe the function of lysosomes in digesting material and their role in programmed cell death (apoptosis).
- I can compare the roles of vacuoles in plant and animal cells, including the maintenance of turgor pressure in plants.
- I can describe the structure of chloroplasts and their function as the location for photosynthesis.
2.2 Cell Size
- I can describe how surface area-to-volume ratios affect a biological system's ability to exchange nutrients, waste, and thermal energy with the environment.
2.3 Plasma Membrane
- I can describe how the hydrophilic phosphate heads and hydrophobic fatty acid tails of phospholipids orient themselves to form a membrane.
- I can explain how the hydrophilic and hydrophobic regions of embedded proteins dictate their position within or on the surface of the cell membrane.
- I can describe the fluid mosaic model and identify the structural framework of phospholipids, proteins, steroids, glycoproteins, and glycolipids.
2.4 Membrane Permeability
- I can state that plasma membranes separate internal and external environments and that selective permeability is due to the hydrophobic interior.
- I can describe how small nonpolar molecules pass freely, while hydrophilic substances require embedded channels and transport proteins.
- I can explain that nonpolar hydrocarbon tails prevent the movement of ions and polar molecules, but small polar uncharged molecules can pass in small amounts.
- I can explain how cell walls in Bacteria, Archaea, Fungi, and plants provide a structural boundary, permeability barrier, and protection from osmotic lysis.
2.5 Membrane Transport
- I can describe passive transport as the movement of molecules from high to low concentration without metabolic energy.
- I can describe active transport as requiring direct energy input to move molecules, often against their concentration gradient.
- I can explain how endocytosis and exocytosis require energy to move large substances into and out of cells via vesicle formation and fusion.
2.6 Facilitated Diffusion
- I can describe how charged ions require transport or channel proteins to move across the membrane, and how this movement can lead to membrane polarization.
- I can explain that facilitated diffusion moves large polar molecules down their concentration gradient without the input of energy.
- I can identify aquaporins as the specific proteins that transport large quantities of water across membranes.
2.7 Tonicity and Osmoregulation
- I can describe the movement of water between hypotonic, hypertonic, and isotonic environments and explain osmosis in terms of water potential.
- I can calculate solute potential and explain how osmoregulation maintains water balance and internal solute composition.
2.8 Mechanisms of Transport
2.9 Cell Compartmentalization
- I can describe the membrane-bound structures found in eukaryotic cells.
- I can explain how membrane-bound organelles compartmentalize metabolic processes and enzymatic reactions.
- I can explain how internal membranes contribute to the compartmentalization of eukaryotic cell functions.
- I can describe how internal membranes minimize competing interactions and increase surface area for cellular reactions.
2.10 Origins of Cell Compartmentalization
Cells: common questions
What is in Unit 2: Cells?
It covers 10 topics: 2.1 Cell Structure and Function; 2.2 Cell Size; 2.3 Plasma Membrane; 2.4 Membrane Permeability; 2.5 Membrane Transport; 2.6 Facilitated Diffusion; 2.7 Tonicity and Osmoregulation; 2.8 Mechanisms of Transport; 2.9 Cell Compartmentalization; 2.10 Origins of Cell Compartmentalization.
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