Week 2 Membrane transport lab PDF

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BIOS251 OL, Week 2 Lab Name: Rachel Wells

OL Lab 2: Cell Membrane and Transport: Learn how transporters keep cells healthy Learning Objectives:     

Describe the plasma membrane structure using the fluid mosaic model Recognize the relative permeability of lipid bilayers to different classes of molecule Compare active and passive transport of molecules Identify the 3 modes of active transport and the different classes of ion channel and carrier molecules Relate the expression of specific transport proteins to the cell’s role

Introduction: A variety of substances move in and out of the cells through the plasma membrane. Membrane transport is vital for cellular activities. The cells need to be healthy for the body to work efficiently. From filtration in the kidneys to the contraction of muscles during exercise, membrane transport contributes to many processes. In this simulation, you will learn about the structure and function of the cell membrane, and discover why membrane transporters are vital for healthy cells and the function of organ systems. In the first part of your mission, you will be introduced to the concepts of selective permeability and the fluid mosaic models of the plasma membrane. You will explore why cells need specialized transporter proteins to transport cargo molecules across their membranes. While some molecules can diffuse across the cell membrane, most molecules require a transporter protein to enter or leave the cell. In the later part of the simulation, you will set up a fluorescence microscopy experiment to learn how the channels, carriers, and pumps that exist in the membrane ensures that only the right molecules enter under the right conditions and help not only to keep the cell healthy but also help organ systems to function.

Part 1: Complete Labster Cell Membrane and Transport

BIOS251 OL, Week 2 Lab Name: Rachel Wells

Part 2: Report and Reflection Purpose: Describe in your own words and in complete sentences, the purpose of this experiment. The purpose of this experiment was to familiarize students with concepts such as selective permeability and understanding the fluid mosaic model of the plasma membrane. After learning the concepts, the lab uses a virtual cell to allow the user to transport it and explore the molecules types that can get through the cell membrane and the necessary transporter proteins. While still exploring the virtual cell, the lab helps to understand and explore the use of different channels, carriers, and pumps. The user looks at each cell condition and chooses the correct transporter proteins, channels, carriers and pumps required for the molecule to get through the cell membrane.

Observations: List 2 observations you have made in this simulation. Two observations I made in this simulation is that ions have the lowest permeability meaning they are least likely to cross the plasma membrane without a transporter protein and hydrophobic molecules can enter the cell without a transporter protein.

Answer all the questions below: 1. In complete sentences and in your own words define the following cellular transport: (2 points) a. Diffusion: Diffusion is the random movement of particles down the concentration gradient from high concentration to low concentration, down a concentration gradient. b. Osmosis: Osmosis is the movement of water molecules down the concentration gradient through a partially permeable membrane. Osmosis moves from a high concentration gradient to a low concentration gradient. The result of osmosis is there is a higher amount of water on ion side of the membrane and an increase in pressure on the higher water content side. Osmosis always moves via passive transport, meaning it does not require energy to move. Water goes in an out of a

BIOS251 OL, Week 2 Lab Name: Rachel Wells

cell at an equal rate, when the outside of the cell has a higher water concentrate than inside the cell, the solution is hypertonic. Hypertonic, diffusion of water out of the cell resulting in the cell shriveling. Hypotonic is the result when the solution on the outside the cell is higher in water therefore there is a diffusion of water into the cell, causing the cell to swell up. c. Facilitated diffusion: Facilitated diffusion is the diffusion of solutes into the plasma membrane by the use of transporter proteins. Molecules move down the concentration gradient from greater concentration to lessor concentration. d. Active transport: Active transport is when solutes move up the concentration gradient from area of low concentration to high concentration. Solutes move up the gradient by pumps and vesicles. An example of a pump is the sodium potassium pump. The sodium potassium pump transports sodium from inside the cell where there are low levels of sodium to outside the cell where they are higher. The sodium potassium pump then brings potassium from extracellular fluid inside the cell where the potassium levels are higher. The other form of active transport are vesiculas, which transport molecules and large particles into the cell by phagocytosis or pinocytosis.

2. Using the figure below, identify the cellular structures and its function. (6 points)

BIOS251 OL, Week 2 Lab Name: Rachel Wells

A

Cell Structure Nuclear envelope

B

Rough endoplasmic reticulum

C

Nucleolus

D

Cytoplasm

E

Nuclear Pores

F

Cell Membrane

G

Mitochondrion

H

Microfilaments

I

Lysosome

Functions A membrane barrier between the cytoplasm and the nucleus containing proteins responsible for gene regulation and chromatin organization. Covered in ribosome and plays an important role in the synthesis of proteins. Responsible for ribosomal RNA. Sending subunits of RNA out into the cell to pair with other subunits to make completed ribosome. This process is important for making proteins in a cell. Cytoplasm is the site of all intercellular activity. Control substance movement between the nucleus and cytoplasm. Protect the cell and monitor the molecules entering and exiting the cell. It maintains the proper channels or molecular transport from one cell to another. The cell’s powerhouse, producing most of the cell’s ATP (energy). Microfilaments keep organelle stationary in a cell and aid cell movement. Contains digestive enzymes that breakdown and destroy worn cell parts, bacteria, and viruses.

BIOS251 OL, Week 2 Lab Name: Rachel Wells

3. What is tonicity and how does it affect the condition of the cell? (1 point) Tonicity is an extracellular fluid that is responsible for water movement in and out of a cell. The tonicity affects a cell by contributing to the cell’s volume, therefore it is responsible for weather a cell is hypotonic or hypertonic. A hypotonic solution will cause a cell to swell and a hypertonic solution will cause a cell to shrink.

4. When is a hypotonic IV solution administered to patients? Why? (1 point) Hypotonic IV solution is administered to a patient when the patient is dehydrated. Hypotonic solution allows extracellular fluid to shift intercellular and aids in the maintenance of homeostasis.

5. Reflection: Reflect on at least 2 key concepts you have learned from this simulation. How would you relate it to the physiological functions of the body? Two key concepts learned in this simulation are specialized transporter proteins are in order for molecules to move in and out of the cell and the process of active cell transport uses pumps and vessels in order to regulate the molecules levels inside and outside the cell. These two concepts relate to physiological functions in the body because they are both extremely important processes that help the body maintain homeostasis.

Grading Rubric:

BIOS251 OL, Week 2 Lab Name: Rachel Wells

Activity

Deliverable

Points

Part 1

Complete simulation

15

Part 2

Complete lab report and answer questions

15

   

Total

Purpose (1 point) Observation (2 points) Questions (10 points) Reflection (2 points)

Complete all lab activities

30...