Due Wednesday, January 3rd

Unit 3 Free-Response Exam Wednesday, January5th

Warm-Ups, CTQs, and ClosuresWeek 15

monday / tuesday / wednesday
ligand / receptor / secondary messenger / phosphorylation / hormone / antibody / antigen / humoral response / cell-mediated response
thursday / friday
action potential / Na+/K+ pump / neurotransmitter / inhibitory/stimulatory / vertebrate

Monday, 12/11

Warm-Up:Explain how an enzyme is specific to a substrate.

CTQ #1:Describe the molecular nature of a chemical signal and explain the key elements of a signal transduction pathway responsible for causing a cellular response. Predict how increasing concentration levels of signal would affect the cellular response. (LO3.31, 3.36, 3.38)

CTQ #2:Signaling pathways are present in every living organism today. However, different signaling pathways arose at different points in our ancestral lineage. Which of the following scientific questions best addresses when during evolution specific signal transduction pathways arose? (LO 3.32)

  1. Which signaling pathways occur only in human brain cells, and which occur in all human cells?
  2. Which domains of life contain the gene encoding a particular ligand?
  3. How many signaling pathways do humans have compared to flies and rodents?
  4. How is the physiological function of plant signaling pathways different from that of mammals?

Closure:Explain how a specific cellular signal can promote production of a specific protein. (LO 3.22)

Tuesday, 12/12

Warm-Up:Create a representation showing a generic cell signaling pathway before and after a ligand binds to a receptor. Show how binding to a ligand regulates gene expression. (LO 3.23, 3.33, 3.35)

CTQ #1:Describe the advantages and disadvantages of an organism using a long-range ligand (such as a hormone) for signal transduction instead of a direct (short-range) signal. (LO 3.34)

CTQ #2:Patients suffering from Type I diabetes are required to take regular insulin injections to maintain low blood sugar levels. Insulin is a hormone ligand that has been proven to reduce the release of glucose from liver cells. Justify the claim that insulin causes liver cells to stop secreting glucose. (LO 3.37)

Closure:Explain how a drug could affect signal reception between cells and, consequently, the entire signal transduction pathway. (LO 3.39)

Wednesday, 12/13

Warm-Up:Explain how low insulin levels lead to increased glucose secretion into the blood in the context of cell communication. Be sure to include a discussion on a change in gene expression. (LO 3.38)

CTQ #1:Explain how cells of the immune system communicate with other cells. (LO 2.43)

CTQ #2:Create a representation (cartoon, diagram, flow map, et cetera) showing how a vaccine prepares the body for a fast immune response to a specific pathogen. (LO 2.29)

Closure: Compare the immune response to cell signaling: which components are analogous to ligands, receptors, and cellular response? (LO 2.43)

Thursday, 12/14

Warm-Up:Explain how proteins are secreted (released) by cells.

CTQ #1:Describe how neurons detect signals and transmit information. (LO 3.45)

CTQ #2:
Researchers investigating the regulation of neurotransmitter release from presynaptic neurons proposed a model (above) in which CDK5, a protein expressed in axon terminals, inhibits the movement of synaptic vesicles to the presynaptic membrane.
Based on the model, which of the following describes the most likely mechanism by which CDK5 regulates neurotransmitter release?

  1. CDK5 adds methyl groups to DNA, altering expression of genes required for synthesis of neurotransmitters.
  2. CDK5 promotes the rearrangement of the lipid molecules of two bilayers into a single membrane.
  3. CDK5 alters the activity of other proteins involved in the movement of synaptic vesicles to the plasma membrane.
  4. CDK5 binds to gated ion channels in the postsynaptic membrane, resulting in diffusion of calcium ions.

Closure:Explain how a neuron receiving neurotransmitters across a synapse produces an action potential.

Friday, 12/15

Warm-Up:Create a representation (cartoon, diagram, flow map, et cetera) to show how the vertebrate nervous system detects transmits information from one neuron to another. (LO 3.49)

CTQ #1:In vertebrates, sensory neurons detect sensations and relay the information to the spinal cord. Neurons in the spinal cord then relay the information to the brain. Explain how a heat sensation detected in a fingertip could result in an inhibitory response in the brain. (LO 3.44, 3.46)

CTQ #2:A natural response to sensing danger is an increased heart rate: for example, when some sees a dangerous animal, the heart starts beating very quickly. Draw and explain the process by which the nervous system senses the bear through the eye, relays and integrates the information within the brain, and produces the heart-rate response. (LO 3.43, 3.47, 3.48, 3.50)

Closure: Actually, the nervous system increases the heart rate in a person by producing adrenaline (epinephrine), which is a hormone produced by the adrenal medulla gland and travels through the bloodstream to the heart. Re-draw your dangerous bear schematic, and explain how adrenaline causes cardiac (heart) muscle cells to start contracting (beating). (LO 3.43, LO 3.47, LO 3.34)

Learning Objectives This Week:

LO 3.22 explain how signal pathways mediate gene expression, including how this process can affect protein production.

LO 3.23 use representations to describe mechanisms of the regulation of gene expression.

LO 3.31 describe basic chemical processes for cell communication shared across evolutionary lines of descent.

LO 3.32 generate scientific questions involving cell communication as it relates to the process of evolution.

LO 3.33 use representations and appropriate models to describe features of a cell signaling pathway.

LO 3.34 construct explanations of cell communication through cell-to-cell direct contact or through chemical signaling.

LO 3.35 create representations that depict how cell-to-cell communication occurs by direct contact or from a distance through chemical signaling.

LO 3.36 describe a model that expresses the key elements of signal transduction pathways by which a signal is converted to a cellular response.

LO 3.37 justify claims based on scientific evidence that changes in signal transduction pathways can alter cellular response.

LO 3.38 describe a model that expresses key elements to show how changes in signal transduction can alter cellular response.

LO 3.39 construct an explanation of how certain drugs affect signal reception and, consequently, signal transduction pathways.

LO 2.29 create representations and models to describe immune responses.

LO 2.43 connect the concept of cell communication to the functioning of the immune system.

LO 3.43 construct an explanation, based on scientific theories and models, about how nervous systems detect external and internal signals, transmit and integrate information, and produce responses.

LO 3.44 describe how nervous systems detect external and internal signals.

LO 3.45 describe how nervous systems transmit information.

LO 3.46 describe how the vertebrate brain integrates information to produce a response.

LO 3.47 create a visual representation of complex nervous systems to describe/explain how these systems detect external and internal signals, transmit and integrate information, and produce responses.

LO 3.48 create a visual representation to describe how nervous systems detect external and internal signals.

LO 3.49 create a visual representation to describe how nervous systems transmit information.

LO 3.50 create a visual representation to describe how the vertebrate brain integrates information to produce a response.