California State University, East Bay

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BIOL

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BIOL-1402

Q4

 17000 Points

Plants undergo phototropism in response to directional blue light that is perceived by the photoreceptor phototropin. Using gene, hormone, enzyme, etc. names, diagram the signaling pathway resulting in phototropism that occurs in cells on the shaded side of a stem based on the information that you learned in class. Begin the pathway with the first component after phototropin is activated.

Answer & Explanation

Phototropin → Starch Degrading Enzyme α-amylase → Auxin Hormone → Auxin Transport Proteins → Auxin-Induced Gene Expression → Actin Cytoskeleton Reorganization → Plant Cell Expansion → Plant Growth Directional Change → Phototropism

Step-by-step explanation

Signaling Pathway for Phototropism

Phototropin Activation: Phototropin is a blue light-sensitive photoreceptor located in the plasma membrane of plant cells. Upon activation by blue light, phototropin triggers a signaling cascade that leads to plant cell expansion and directional growth towards the light source, also known as phototropism.

Starch Degrading Enzyme α-amylase: Once activated, phototropin induces the production of the starch degrading enzyme α-amylase. α-amylase is an enzyme responsible for the breakdown of starch into the simple sugars, glucose and maltose. The production of α-amylase is necessary to provide the energy needed for the cell expansion and directional growth involved in phototropism.

Auxin Hormone: The production of α-amylase also triggers the production of the auxin hormone. Auxin is a plant hormone that is involved in a variety of plant growth and development processes, including phototropism.

Auxin Transport Proteins: Once produced, the auxin hormone is transported across the plasma membrane of the cells involved in the phototropism respons

Q4

 17000 Points

Plants undergo phototropism in response to directional blue light that is perceived by the photoreceptor phototropin. Using gene, hormone, enzyme, etc. names, diagram the signaling pathway resulting in phototropism that occurs in cells on the shaded side of a stem based on the information that you learned in class. Begin the pathway with the first component after phototropin is activated.

Answer & Explanation

Phototropin → Starch Degrading Enzyme α-amylase → Auxin Hormone → Auxin Transport Proteins → Auxin-Induced Gene Expression → Actin Cytoskeleton Reorganization → Plant Cell Expansion → Plant Growth Directional Change → Phototropism

Step-by-step explanation

Signaling Pathway for Phototropism

Phototropin Activation: Phototropin is a blue light-sensitive photoreceptor located in the plasma membrane of plant cells. Upon activation by blue light, phototropin triggers a signaling cascade that leads to plant cell expansion and directional growth towards the light source, also known as phototropism.

Starch Degrading Enzyme α-amylase: Once activated, phototropin induces the production of the starch degrading enzyme α-amylase. α-amylase is an enzyme responsible for the breakdown of starch into the simple sugars, glucose and maltose. The production of α-amylase is necessary to provide the energy needed for the cell expansion and directional growth involved in phototropism.

Auxin Hormone: The production of α-amylase also triggers the production of the auxin hormone. Auxin is a plant hormone that is involved in a variety of plant growth and development processes, including phototropism.

Auxin Transport Proteins: Once produced, the auxin hormone is transported across the plasma membrane of the cells involved in the phototropism respons