UNIT 2: Cell Structure & Function Riedell AP Bio Cells Unit webpage
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| Big
Idea |
LO/EK description | ||
| SYI- | 1.D | Describe the structure and/ or function of subcellular components and organelles. |
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| SYI | 1.D.1 | Ribosomes comprise ribosomal RNA (rRNA) and protein. Ribosomes synthesize protein according to mRNA sequence. |
Organelle speed
dating Cell parts organizer |
| SYI | 1.D.2 | Ribosomes are found in all forms of life, reflecting the common ancestry of all known life. | Draw Endosymbiotic theory |
| SYI | 1.D.3 |
Endoplasmic
reticulum (ER) occurs in two forms—smooth and rough. Rough ER is
associated with membrane-bound ribosomes— a. Rough ER compartmentalizes the cell. b. Smooth ER functions include detoxification and lipid synthesis EXCLUSION STATEMENT-Specific funcitons of smooth ER in specialized cells are beyond the scope of the course and the AP Exam |
Organelle speed
dating Cell parts organizer |
| SYI | 1.D.4 |
The Golgi
complex is a membrane-bound structure that consists of a series of
flattened membrane sacs— a. Functions of the Golgi include the correct folding and chemical modification of newly synthesized proteins and packaging for protein trafficking. EXCLUSION STATEMENT: The role of the Golgi in the synthesis of specific phospholipids and the packaging of specific enzymes for lysosomes, peroxisomes, and secretory vesicles are beyond the scope of the course and the AP Exam. ILLUSTRATIVE EXAMPLE- Glycosylation and other chemical modifications of protein that take place witin the Golgi and determine protein function or targeting b Mitochondria have a double membrane. The outer membrane is smooth, but the inner membrane is highly convoluted, forming folds. c. Lysosomes are membrane enclosed sacs that contain hydrolytic enzymes. d. A vacuole is a membrane bound sac that plays many differing roles in plants, a specialized large vacuole serves multiple functions. e. Chloroplasts are specialized organelles that are found in photosynthetic algae and plants. Chloroplasts have a double membrane. |
Organelle speed
dating Cell parts organizer |
| SYI | 1.E | Explain how subcellular components and organelles contribute to the function of the cell. |
Organelle speed
dating Cell parts organizer |
| SYI | 1.E.1 |
Organelles and
subcellular structures, and the interactions among them, support
cellular function— a. Endoplasmic reticulum provides mechanical support, carries out protein synthesis on membrane-bound ribosomes, and plays a role in intracellular transport. b. Mitochondrial double membrane provides compartments for different metabolic reactions. c. Lysosomes contain hydrolytic enzymes, which are important in intracellular digestion, the recycling of a cell’s organic materials, and programmed cell death (apoptosis). d. Vacuoles have many roles, including storage and release of macromolecules and cellular waste products. In plants, it aids in retention of water for turgor pressure." |
Organlle speed dating Cell parts organizer DRAW a MITOCHONDRION |
| SYI | 1.F | Describe the structural features of a cell that allow organisms to capture, store, and use energy. | Organelle speed dating |
| SYI | 1.F.1 | The folding of the inner membrane increases the surface area, which allows for more ATP to be synthesized. |
Draw a Chloroplast DRAW a MITOCHONDRION Draw Photosynthesis (Energentics unit 3) |
| SYI | 1.F.2 | Within the chloroplast are thylakoids and the stroma. | |
| SYI | 1.F.3 | The thylakoids are organized in stacks, called grana. | |
| SYI | 1.F.4 | Membranes contain chlorophyll pigments and electron transport proteins that comprise the photosystems. | |
| SYI | 1.F.5 | The light-dependent reactions of photosynthesis occur in the grana. | |
| SYI | 1.F.6 | The stroma is the fluid within the inner chloroplast membrane and outside of the thylakoid. | |
| SYI | 1.F.7 | The carbon fixation (Calvin-Benson cycle) reactions of photosynthesis occur in the stroma. | |
| SYI | 1.F.8 | The Krebs cycle (citric acid cycle) reactions occur in the matrix of the mitochondria. | |
| SYI | 1.F.9 | Electron transport and ATP synthesis occur on the inner mitochondrial membrane. | |
| ENE | 1.B | Explain the effect of surface area-to-volume ratios on the exchange of materials between cells or organisms and the environment. | |
| ENE | 1.B.1 | Surface area-to-volume ratios affect the ability of a biological system to obtain necessary resources, eliminate waste products, acquire or dissipate thermal energy, and otherwise exchange chemicals and energy with the environment. |
Why Are Cells Small? video SA/volume ratio opener Osmosis Diffusion Lab #1 |
| ENE | 1.B.2 |
The surface area of the
plasma membrane must be large enough to adequately exchange materials— a. These limitations can restrict cell size and shape. Smaller cells typically have a higher surface area-to-volume ratio and more efficient exchange of materials with the environment. b. As cells increase in volume, the relative surface area decreases and the demand for internal resources increases. c. More complex cellular structures (e.g., membrane folds) are necessary to adequately exchange materials with the environment. d. As organisms increase in size, their surface area-to-volume ratio decreases, affecting properties like rate of heat exchange with the environment. ILLUSTRATIVE EXAMPLES - SA/V ratios and Exchange: Root hair cells, Guard cells; Gut epithelial cells ILLUSTRATIVE EXAMPLES- Vacuoles, Cilia, Stomata |
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| ENE | 1.C | Explain how specialized structures and strategies are used for the efficient exchange of molecules to the environment. | |
| ENE | 1.C.1 | Organisms have evolved highly efficient strategies to obtain nutrients and eliminate wastes. Cells and organisms use specialized exchange surfaces to obtain and release molecules from or into the surrounding environment. | |
| ENE | 2.A | Describe the roles of each of the components of the cell membrane in maintaining the internal environment of the cell. | |
| ENE | 2.A.1 | Phospholipids have both hydrophilic and hydrophobic regions. The hydrophilic phosphate regions of the phospholipids are oriented toward the aqueous external or internal environments, while the hydrophobic fatty acid regions face each other within the interior of the membrane. |
Membrane fluidity Phospholipid movement EXPLAIN it to HOMER -Phospholipids Modeling Biomolecules-Lipids (Chemistry of Life unit) |
| ENE | 2.A.2 | Embedded proteins can be hydrophilic, with charged and polar side groups, or hydrophobic, with nonpolar side groups. | |
| ENE | 2.B | Describe the Fluid Mosaic Model of cell membranes. | |
| ENE | 2.B.1 | Cell membranes consist of a structural framework of phospholipid molecules that is embedded with proteins, steroids (such as cholesterol in eukaryotes), glycoproteins, and glycolipids that can flow around the surface of the cell within the membrane. |
Membrane fluidity Phospholipid movement EXPLAIN it to HOMER -Phospholipids Modeling Biomolecules-Lipids (Chemistry of Life unit) |
| ENE | 2.C | Explain how the structure of biological membranes influences selective permeability. | |
| ENE | 2.C.1 | The structure of cell membranes results in selective permeability. |
Organelle speed
dating Cell parts organizer EXPLAIN it to HOMER -Phospholipids |
| ENE | 2.C.2 |
Cell membranes
separate the internal environment of the cell from the external
environment. |
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| ENE | 2.C.3 | Selective permeability is a direct consequence of membrane structure, as described by the fluid mosaic model. | |
| ENE | 2.C.4 | Small nonpolar molecules, including N2, O2, and CO2, freely pass across the membrane. Hydrophilic substances, such as large polar molecules and ions, move across the membrane through embedded channel and transport proteins. |
STOLAF ANIMATIONS Transport desktop concept map Transport comparison |
| ENE | 2.C.5 | Polar uncharged molecules, including H2O, pass through the membrane in small amounts | |
| ENE | 2.D | Describe the role of the cell wall in maintaining cell structure and function. | |
| ENE | 2.D.1 | Cell walls provide a structural boundary, as well as a permeability barrier for some substances to the internal environments. |
Organlle speed
dating Cell parts organizer Make a connection antibiotic opener |
| ENE | 2.D.2 | Cell walls of
plants, prokaryotes, and fungi are composed of complex carbohydrates. |
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| ENE | 2.E | Describe the mechanisms that organisms use to maintain solute and water balance. | |
| ENE | 2.E.1 | Passive transport is the net movement of molecules from high concentration to low concentration without the direct input of metabolic energy. |
Transport desktop concept map Transport comparison |
| ENE | 2.E.2 | Passive transport plays a primary role in the import of materials and the export of wastes. | |
| ENE | 2.E.3 | Active transport requires the direct input of energy to move molecules from regions of low concentration to regions of high concentration. | |
| ENE | 2.F | Describe the mechanisms that organisms use to transport large molecules across the plasma membrane. | |
| ENE | 2.F.1 | The selective permeability of membranes allows for the formation of concentration gradients of solutes across the membrane. |
Transport desktop concept map Transport comparison |
| ENE | 2.F.2 |
The processes
of endocytosis and exocytosis require energy to move large molecules
into and out of cells— a. In exocytosis, internal vesicles fuse with the plasma membrane and secrete large macromolecules out of the cell. b. In endocytosis, the cell takes in macromolecules and particulate matter by forming new vesicles derived from the plasma membrane. |
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| ENE | 2.G | Explain how the structure of a molecule affects its ability to pass through the plasma membrane. | |
| ENE | 2.G.1 |
Membrane
proteins are required for facilitated diffusion of charged and large
polar molecules through a membrane— a. Large quantities of water pass through aquaporins. b. Charged ions, including Na+ and K+, require channel proteins to move through the membrane. c. Membranes may become polarized by movement of ions across the membrane. |
Transport desktop concept map Transport comparison Nerve Muscle Kinds of transport BILL ?'s |
| ENE | 2.G.2 | Membrane proteins are necessary for active transport. | |
| ENE | 2.G.3 | Metabolic energy (such as from ATP) is required for active transport of molecules and/ or ions across the membrane and to establish and maintain concentration gradients. | |
| ENE | 2.G.4 | The Na+/K+ ATPase contributes to the maintenance of the membrane potential. | |
| ENE | 2.H | Explain how concentration gradients affect the movement of molecules across membranes. | |
| ENE | 2.H.1 |
External
environments can be hypotonic, hypertonic or isotonic to internal
environments of cells— a. Water moves by osmosis from areas of high water potential/low osmolarity/ low solute concentration to areas of low water potential/high osmolarity/high solute concentration. |
Transport desktop concept map Transport comparison Water Potential Problems #1 Water Potential Problems #2 |
| ENE | 2.I | Explain how osmoregulatory mechanisms contribute to the health and survival of organisms. | |
| ENE | 2.I.1 | Growth and
homeostasis are maintained by the constant movement of molecules across
membranes. ILLUSTRATIVE EXAMPLES: Contractile vacuoles in protists; Central vacuole in plant cells |
Water potential Elodea osmosis Red onion plasmolysis How can water kill you? video |
| ENE | 2.I.2 | Osmoregulation maintains water balance and allows organisms to control their internal solute composition/water potential. | |
| ENE | 2.J | Describe the processes that allow ions and other molecules to move across membranes. | |
| ENE | 2.J.1 | A variety of processes allow for the movement of ions and other molecules across membranes, including passive and active transport, endocytosis and exocytosis. |
Transport desktop concept map Transport comparison |
| ENE | 2.K | Describe the membrane-bound structures of the eukaryotic cell. | |
| ENE | 2.K.1 | Membranes and membrane-bound organelles in eukaryotic cells compartmentalize intracellular metabolic processes and specific enzymatic reactions. | Draw Mitochondria |
| ENE | 2.L | Explain how internal membranes and membrane-bound organelles contribute to compartmentalization of eukaryotic cell functions. | |
| ENE | 2.L.1 | Internal membranes facilitate cellular processes by minimizing competing interactions and by increasing surface areas where reactions can occur | Draw Mitochondria |
| EVO | 1.A | Describe similarities and/or differences in compartmentalization between prokaryotic and eukaryotic cells | |
| EVO | 1.A.1 | Explain how internal membranes and membrane-bound organelles contribute to compartmentalization of eukaryotic cell functions | POGIL-Prokaryotic/Eukaryotic Cells |
| EVO | 1.A.2 | Prokaryotes generally lack internal membrane-bound organelles but have internal regions with specialized structures and functions. | |
| EVO | 1.A.3 | Eukaryotic cells maintain internal membranes that partition the cell into specialized regions. | |
| EVO | 1.B | Describe the relationship between the functions of endosymbiotic organelles and their free-living ancestral counterparts. |
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| EVO | 1.B.1 | Membrane-bound organelles evolved from previously free-living prokaryotic cells via endosymbiosis. |
Endosymbiotic theory video Draw Endosymbiotic theory |
| The learning targets highlighted below are taken from the CED HEREDITY | |||
| IST | 3.A | Describe the ways that cells can communicate with one another. | |
| IST | 3.A.1 |
Cells
communicate with one another through direct contact with other cells or
from a distance via chemical signaling— a. Cells communicate by cell-to-cell contact. ILLUSTRATIVE EXAMPLES: Immune cells interact by cell-to-cell contact, antigen presenting cells (APCs), helper T cells, and killer cells; Plasmodesmata between plant cells allow material to be transported from cell to cell |
POGIL-Cell Communication |
| IST | 3.B | Explain how cells communicate with one another over short and long distances. | |
| IST | 3.B.1 |
Cells
communicate over short distances by using local regulators that target
cells in the vicinity of the signal-emitting cell — a. Signals released by one cell type can travel long distances to target cells of another cell type. ILLUSTRATIVE EXAMPLES- Neurotransmitters, Plant immune response, Quorum sensing in bacteria, Morphogens in embryonic development |
POGIL-Cell Communication |
| IST | 3.C | Describe the components of a signal transduction pathway. | |
| IST | 3.C.1 | Signal transduction pathways link signal reception with cellular responses. |
MODELING SIGNAL TRANSDUCTION PATHWAYS CUTOUTS |
| IST | 3.C.2 | Many signal transduction pathways include protein modification and phosphorylation cascades. | |
| IST | 3.D | Describe the role of components of a signal transduction pathway in producing a cellular response. | |
| IST | 3.D.1 |
Signaling
begins with the recognition of a chemical messenger—a ligand—by a
receptor protein in a target cell— a. The ligand-binding domain of a receptor recognizes a specific chemical messenger, which can be a peptide, a small chemical, or protein, in a specific one-to-one relationship. b. G protein-coupled receptors are an example of a receptor protein in eukaryotes. ILLUSTRATIVE EXAMPLES- Insulin, Human growth hormone, Thyroid hormone, Testosterone, Extrogen |
MODELING SIGNAL TRANSDUCTION PATHWAYS CUTOUTS |
| IST | 3.D.2 |
Signaling
cascades relay signals from receptors to cell targets, often amplifying
the incoming signals, resulting in the appropriate responses by the
cell, which could include cell growth, secretion of molecules, or gene
expression— a. After the ligand binds, the intracellular domain of a receptor protein changes shape initiating transduction of the signal. b. Second messengers (such as cyclic AMP) are molecules that relay and amplify the intracellular signal. c. Binding of ligand-to-ligand-gated channels can cause the channel to open or close. |
MODELING SIGNAL TRANSDUCTION PATHWAYS CUTOUTS |
| IST | 3.E | Describe the role of the environment in eliciting a cellular response. | |
| IST | 3. E.1 | Signal
transduction pathways influence how the cell responds to its environment ILLUSTRATIVE EXAMPLES- Use of chemical messengers by microbes to communicate with toher nearby cells and to regulate specific pathways in response to population density (quorum sensing); Epinephrine stimulation of glucogen breakdown in mammals |
POGIL-Cell Communication MODELING SIGNAL TRANSDUCTION PATHWAYS CUTOUTS BILL Cell signaling comparison |
| IST | 3.F | Describe the different types of cellular responses elicited by a signal transduction pathway. | |
| IST | 3.F.1 | Signal
transduction may result in changes in gene expression and cell function,
which may alter phenotype or result in programmed cell death
(apoptosis). ILLUSTRATIVE EXAMPLES- Cytokines regulate gene expression to allow for cell replication and division; Mating pheromones in yeast triger mating gene expression; Espression of the SRY gene triggers the male sexual development pathway in animals; Ethylene levels cause changes in the production of different enzymes allowing fruits to ripen. |
MODELING SIGNAL TRANSDUCTION PATHWAYS CUTOUTS BILL Cell signaling comparison |
| IST | 3.G | Explain how a change in the structure of any signaling molecule affects the activity of the signaling pathway. | |
| IST | 3.G.1 |
Changes in
signal transduction pathways can alter cellular response— a. Mutations in any domain of the receptor protein or in any component of the signaling pathway may affect the downstream components by altering the subsequent transduction of the signal. |
Effects of Changes in Pathways |
| IST | 3.G.2 | Chemicals that interfere with any component of the signaling pathway may activate or inhibit the pathway. | |
| ENE | 3.A | Describe positive and/ or negative feedback mechanisms. | |
| ENE | 3.A.1 | Organisms use feedback mechanisms to maintain their internal environments and respond to internal and external environmental changes. |
Homeostatic Loops Homeostasis Hugs |
| ENE | 3.B | Explain how negative feedback helps to maintain homeostasis. | |
| ENE | 3.B.1 | Negative
feedback mechanisms maintain homeostasis for a particular condition by
regulating physiological processes. If a system is perturbed, negative
feedback mechanisms return the system back to its target set point.
These processes operate at the molecular and cellular levels. ILLUSTRATIVE EXAMPLES- Blood sugar regulation by insulin/glucagon |
Positive & Negative Feedback loops |
| ENE | 3.C | Explain how positive feedback affects homeostasis. | |
| ENE | 3.C.1 | Positive
feedback mechanisms amplify responses and processes in biological
organisms. The variable initiating the response is moved farther away
from the initial set point. Amplification occurs when the stimulus is
further activated, which, in turn, initiates an additional response that
produces system change. ILLUSTRATIVE EXAMPLES- Lactation in mammals; Onset of labor in childbirth; Ripening of fruit |
Positive & Negative Feedback loops |