Unit 2 Comprehensive Study Guide: Cell Transport, Osmoregulation, and Water Potential

Unit 2 Exam Scope & Topics

• Primary Unit Coverage Areas:

  • Cell Structure and Function
  • Cell Size
  • Plasma Membrane
  • Membrane Permeability
  • Membrane Transport
  • Facilitated Diffusion
  • Tonicity and Osmoregulation
  • Mechanism of Transport
  • Cell Compartmentalization
  • Origins of Cell Compartmentalization

• Progress Check - $31$ Multiple Choice Questions (MCQs):

  • Seating Constraint: Students must stay in assigned seats.
  • Assignment Submission: Due today in class.
  • Review Protocol:
  • Take out class notes.
  • Treat the progress check as a test review exercise.
  • Highlight or annotate notes as corresponding concepts appear in questions.
  • During subsequent class discussion, students must explain their scientific reasoning.

Plant Water Potential & Transport Mechanics

• Water Potential Gradient in Vascular Plants:
  • Vascular plants rely on water potential differences to drive the movement of water from the soil through the plant body to the leaves.
  • Water potential directly influences the water potential gradient established along the path from roots to leaves.
  • Core stages in plant water transport:
  • Water absorption by root systems from soil.
  • Upward travel of water through the vascular system of the plant.
  • Evaporative loss and transpiration from leaf surfaces.

Osmoregulation & Paramecium Contractile Vacuole FRQ

• Free-Response Question (FRQ) Writing Instructions:

  • Read each prompt carefully prior to answering.
  • Write responses in the designated space provided for each question part.
  • All responses must be composed in complete paragraph form.
  • Outlines, bulleted lists, or standalone diagrams alone are not acceptable and will not be scored.
  • Practice timer duration: $20:00$ minutes.

• Biological Context of Osmoregulation in Paramecia:

  • Paramecia are single-celled aquatic eukaryotes capable of surviving in environments with a wide range of salinities.
  • They utilize contractile vacuoles to maintain internal homeostasis under varying environmental salt concentrations.
  • Vacuole mechanism: Contractile vacuoles fill with cytosolic fluid and subsequently contract to pump the excess fluid out of the cell body.

• Scientific Experiment & Data:

  • Objective: Determine the effect of environmental salinity on contractile vacuole activity.
  • Experimental Procedure: Scientists maintained separate groups of paramecia in water with different salinities over a period of one month.
  • Quantitative Metric Measured: The average amount of fluid ejected from the contractile vacuoles in each group each time the vacuoles contracted.

• Table 1. Contractile Fluid Output by Paramecia Adapted to Different Salinities:

  • Salinity of Maintenance Water: $10\,\text{milliosmoles of solute/kg}$ (freshwater environment).
  • Average Fluid Output of Contractile Vacuole: $1.3\,\text{picoliters/minute}$.

Class Agendas & Learning Resources

• Class Agenda for September 29 ($9/29$):

  • Science Starter:
  1. Get laptop.
  2. Find this week's slide deck.
  • Daily Sequence:
  • Science Starter
  • Pressure Potential
  • Blooket Review Game
  • FRQ Practice

• Class Agenda for September 30 ($9/30$):

  • Required Science Starter Supplies:
  • Whiteboard
  • Marker
  • Eraser
  • Daily Sequence:
  • Science Starter
  • Whiteboard Review
  • Look at FRQ
  • Homework: Review for Unit 2 Exam.

• Review Game Access:

  • Blooket URL link: https://play.blooket.com/play?hwld=6abbec21c3da9d7aae2601d6