Unit: Cell Communication and Cell Cycle & Mitosis

(reorganized from the College Board AP Biology Curriculum Framework 2012 by David Knuffke)


Jump to Lesson 2: Cell Cycle & Mitosis, Not on the National Exam


Lesson 1: Cell Communication

Essential knowledge 3.B.2: A variety of intercellular and intracellular signal transmissions mediate gene expression.


a. Signal transmission within and between cells mediates gene expression.

To foster student understanding of this concept, instructors can choose an illustrative example such as:

b. Signal transmission within and between cells mediates cell function.

To foster student understanding of this concept, instructors can choose an illustrative example such as:


Learning Objectives:

LO 3.22 The student is able to explain how signal pathways mediate gene expression, including how this process can affect protein production. [See SP 6.2]

Lesson 5: Cell Communication

Enduring understanding 3.D: Cells communicate by generating, transmitting and receiving chemical signals.


Essential knowledge 3.D.1: Cell communication processes share common features that reflect a shared evolutionary history.

a. Communication involves transduction of stimulatory or inhibitory signals from other cells, organisms or the environment. [See also 1.B.1]

b. Correct and appropriate signal transduction processes are generally under strong selective pressure.

c. In single-celled organisms, signal transduction pathways influence how the cell responds to its environment.

To foster student understanding of this concept, instructors can choose an illustrative

example such as:

Use of chemical messengers by microbes to communicate with other nearby cells and to regulate specific pathways in response to population density (quorum sensing)

Use of pheromones to trigger reproduction and developmental pathways

Response to external signals by bacteria that influences cell movement

d. In multicellular organisms, signal transduction pathways coordinate the activities within individual cells that support the function of the organism as a whole.

To foster student understanding of this concept, instructors can choose an illustrative

example such as:

Epinephrine stimulation of glycogen breakdown in mammals

Temperature determination of sex in some vertebrate organisms

DNA repair mechanisms

Learning Objectives:

LO 3.31 The student is able to describe basic chemical processes for cell communication shared across evolutionary lines of descent. [See SP 7.2]

LO 3.32 The student is able to generate scientific questions involving cell communication as it relates to the process of evolution. [See SP 3.1]

LO 3.33 The student is able to use representation(s) and appropriate models to describe features of a cell signaling pathway. [See SP 1.4]

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Essential knowledge 3.D.2: Cells communicate with each other through direct contact with other cells or from a distance via chemical signaling.

a. Cells communicate by cell-to-cell contact.

To foster student understanding of this concept, instructors can choose an illustrative example such as:

Immune cells interact by cell-cell contact, antigen-presenting cells (APCs), helper T-cells and killer T-cells. [See also 2.D.4]

Plasmodesmata between plant cells that allow material to be transported from cell to cell.

b. Cells communicate over short distances by using local regulators that target cells in the vicinity of the emitting cell.

To foster student understanding of this concept, instructors can choose an illustrative example such as:

Neurotransmitters

Plant immune response

Quorum sensing in bacteria

Morphogens in embryonic development

c. Signals released by one cell type can travel long distances to target cells of another cell type.


Learning Objectives:

LO 3.34 The student is able to construct explanations of cell communication through cell-to-cell direct contact or through chemical signaling. [See SP 6.2]

LO 3.35 The student is able to create representation(s) that depict how cell-to-cell communication occurs by direct contact or from a distance through chemical signaling. [See SP 1.1]

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Essential knowledge 3.D.3: Signal transduction pathways link signal reception with cellular response.

a. Signaling begins with the recognition of a chemical messenger, a ligand, by a receptor protein.

Evidence of student learning is a demonstrated understanding of each of the following:

1. Different receptors recognize different chemical messengers, which can be peptides, small chemicals or proteins, in a specific one-to-one relationship.

2. A receptor protein recognizes signal molecules, causing the receptor protein’s shape to change, which initiates transduction of the signal.

To foster student understanding of this concept, instructors can choose an

illustrative example such as:

G-protein linked receptors

Ligand-gated ion channels

Receptor tyrosine kinases

b. Signal transduction is the process by which a signal is converted to a cellular response.

Evidence of student learning is a demonstrated understanding of each of the following:

1. Signaling cascades relay signals from receptors to cell targets, often amplifying the incoming signals, with the result of appropriate responses by the cell.

2. Second messengers are often essential to the function of the cascade.

To foster student understanding of this concept, instructors can choose an

illustrative example such as:

Ligand-gated ion channels

Second messengers, such as cyclic GMP, cyclic AMP calcium ions (Ca2+), and inositol triphosphate (IP3)

3. Many signal transduction pathways include:

i. Protein modifications (an illustrative example could be how methylation changes the signaling process)

ii. Phosphorylation cascades in which a series of protein kinases add a phosphate group to the next protein in the cascade sequence


Learning Objectives:

LO 3.36 The student is able to describe a model that expresses the key elements of signal transduction pathways by which a signal is converted to a cellular response. [See SP 1.5]


Lesson 2: Cell Cycle & Mitosis

Enduring understanding 3.A: Heritable information provides for continuity of life.


Essential knowledge 3.A.2: In eukaryotes, heritable information is passed to the next generation via processes that include the cell cycle and mitosis or meiosis plus fertilization.

a. The cell cycle is a complex set of stages that is highly regulated with checkpoints, which determine the ultimate fate of the cell.

Evidence of student learning is a demonstrated understanding of each of the following:

1. Interphase consists of three phases: growth, synthesis of DNA, preparation for mitosis.

2. The cell cycle is directed by internal controls or checkpoints. Internal and external signals provide stop-and-go signs at the checkpoints.

To foster student understanding of this concept, instructors can choose an

illustrative example such as:

3. Cyclins and cyclin-dependent kinases control the cell cycle.

4. Mitosis alternates with interphase in the cell cycle.

5. When a cell specializes, it often enters into a stage where it no longer divides, but it can reenter the cell cycle when given appropriate cues. Nondividing cells may exit the cell cycle; or hold at a particular stage in the cell cycle.

b. Mitosis passes a complete genome from the parent cell to daughter cells.

Evidence of student learning is a demonstrated understanding of each of the following:

1. Mitosis occurs after DNA replication.

2. Mitosis followed by cytokinesis produces two genetically identical daughter cells.

3. Mitosis plays a role in growth, repair, and asexual reproduction

    4. Mitosis is a continuous process with observable structural features along the mitotic process. Evidence of student learning is demonstrated by knowing the order of the processes (replication, alignment, separation).

    Learning Objectives:

    LO 3.7 The student can make predictions about natural phenomena occurring during the cell cycle. [See SP 6.4]

    LO 3.8 The student can describe the events that occur in the cell cycle. [See SP 1.2]

    LO 3.9 The student is able to construct an explanation, using visual representations or narratives, as to how DNA in chromosomes is transmitted to the next generation via mitosis, or meiosis followed by fertilization. [See SP 6.2]


Untested: Not on the College Board national AP Biology Exam

Knowledge of any one cyclin-CdK pair or growth factor is beyond the scope of the course and the AP Exam.