MOVEMENT ACROSS CELL MEMBRANES Biology 9B - Dickson.

MOVEMENT ACROSS CELL MEMBRANES

Biology 9B - Dickson

Homework: None – have a great weekend!

Silent Do Now (in NB w/ date & title) What is the difference between “regular”

diffusion and facilitated diffusion? What do you think the cell membrane is made

of? What does it mean for the membrane to be

“selectively permeable? What is one thing you learned from doing the

StarLogo computer lab?

Bio 9B: Friday, 12/9/11Title: Movement Across Cell Membranes

Today’s Objectives

Describe how the structure of the membrane helps it to function

Describe and explain the following terms: Lipid Bilayer Selective Permeability Diffusion Osmosis Facilitated Diffusion Active Transport

Agenda: Notes/Discussion Exit Ticket and Hand Back Work / Grades

The cell membrane is made of…

Lipid Bilayer Two layers of lipids that form

the outer membrane of a cell. Flexible Strong Do not Dissolve in water

Proteins in the lipid bilayer Help transport molecules

across the membrane

Cell Membrane Structure

Objectives for Class: Use scientific vocabulary to explain how a cell membrane controls what

enters and leaves a cell

zoom

in

Selective Permeability When a membrane only

allows certain substances to pass across the membrane (and not others)

Based on the size, shape, and charge (+/-/neutral) of the substances

Cell Membrane Function



Diffusion Movement of molecules from a

high concentration (more stuff) to low concentration (less stuff)

Spreading out so all areas have an equal concentration

Osmosis Diffusion of water through a

selectively permeable membrane



Diffusion

Osmosis

Methods for Materials to Enter/Leave the Cell

Facilitated Diffusion When a substance diffuses

through a membrane by going through a protein channel

Regular diffusion goes through the lipid bilayer



Prot

ein

Cha

nnel


Active Transport When a substance is pumped across a

membrane from where there’s a low concentration to where there’s a high concentration (against the concentration gradient)

Opposite of diffusion Requires a pump (made of protein)

and ATP energy!




Homework:Complete pages 3 and 5 of the lab

packet. Silent Do Now:

Complete the worksheet. Today’s Goals: You will be able to:

Form a well-reasoned hypothesis about diffusion across membranes.

Test this hypothesis by following a lab procedure to perform an experiment

Create a data table in order to organize and record your results.

Bio 9B: Monday, 12/12/11Title: Diffusion Lab

Lab:Diffusion Across Cell Membranes

Objectives for Class: Design an experiment by drawing from your knowledge of starch,

glucose, cell membranes, and experimental indicators that test for the presence of starch and glucose.

Water

Model Cell w/ Dialysis Tubing Membrane

Starch & Glucose Solution

Set-up Dialysis Bag Moisten tube and tie one end Add the starch & glucose solution to the tube Tie the top of the tube

Rinse w/ tap water to wash excess solution from outside of bag

Set-up Beaker Fill a 250 ml beaker ¾ of the way with water Add Iodine to water – mixture should be

orange Put dialysis bag into beaker with water

and iodine

Diffusion Lab:Procedure Review – Part 1

Water and Iodine




Starch How do we test for it?

Use Iodine How do we know starch has passed through membrane?

Iodine outside the dialysis bag turns from yellow-orange to purplish- brown

Glucose How do we test for it?

Boil it in Benedicts solution or use a glucose test strip How do we know glucose has passed through the

membrane? Glucose test strip will change color

Diffusion Lab:Procedure Review – Part 3



Expectations for Lab Work

Stay at your own table (no wandering) Talk quietly with members of your own

group Stay focused on the lab! Follow every step of the procedure Stay safe – use materials as instructed,

no messing around

Diffusion, Osmosis and Selective Permeability In Action:

http://zoology.okstate.edu/zoo_lrc/biol1114/tutorials/Flash/Osmosis_Animation.htm

New Vocabulary





Homework:Read pages 956-960. Answer questions on the back of the assignment sheet (write answers in notebook)

Silent Do Now (in notebook w/ title & date) Copy the table on the board into your notebook.

Make it huge (fill the whole page of your notebook). Fill in the first column (Results) by filling in each

box with… Was there a color change? If so, describe!

Take out your lab packet and check your data table on page 4 if you can’t remember the results.

Bio 9B: Thursday 12/15/11Title: Diffusion Lab – Analysis & Conclusions

Today’s Objectives & Agenda:You will be able to:

Explain the results of the diffusion experiment Use the lab report rubric to identify mediocre

versus excellent examples of Background Info sections

Write or improve your own Background Info, Analysis, and Conclusion sections of your lab report

Agenda: Class Discussion of Results, Analysis, and

Conclusions Evaluate examples of Background Info Class discussion & brainstorm for this lab’s

Background Info Time to type! And also to conference w/ Ms.

Dickson about past assignments.

Color Change?

Diffusion Across Cell Membranes:Presenting the Data/ Results



Water and Iodine


Bag Turned Purple/ Black

No Color Change to the Water

Glucose Test Strip changed color

Diffusion Lab: Analysis & ConclusionsRESULTS – Was there a color change? Describe!

ANALYSIS – What does this mean?

CONCLUSIONS Why did this happen? Does it support our hypothesis?

Dialysis Bag

Turned from white to purple

Water in Beaker

No change (stayed orange)

Glucose Test Strip

Turned from green to brown-green

Today’s Objectives & Agenda

Discuss and analyze the results of the diffusion experiment

Use the lab report rubric to identify mediocre versus excellent examples of Background Info sections

Identify the strengths and areas for improvement in your own background info section

Agenda: Quick Class Discussion of Results Evaluate examples of Background Info Class discussion & brainstorm Peer editing

Lab: Diffusion Across Cell MembranesWriting Better Background Information Sections

Objectives for Class:

Use the lab report rubric to identify mediocre versus excellent examples of Background Info sections

Task 1 – Do this silently on your own:• Read the two example Background Information sections from the Denatured Enzyme Lab

• Grade them according to the rubric.• Identify strengths and areas for improvement

Sample Background Info sections

Strengths:

Contains scientific terms and definitions

Things to improve:

Unclear definitions

Missing connections

Awkward wording

Topic sentence

Overall grade: Fair

Strengths:

State purpose

Explains all terms

Good connections & examples

“Because…”

“However…”

Things to improve:

Add more vocabulary

Overall grade: Excellent

Example 1 Example 2

Objectives for Class: Use the lab report rubric to identify mediocre versus excellent examples of Background Info sections

Diffusion Lab Background Info

Turn your lab packet to page 5 Your Tasks in A Small Group:1. Make sure everyone has descriptions of each word2. Make sure everyone has descriptions of two more words3. Fill in the Connections part for each word by writing how

it relates to at least one other word, or to the experiment4. At the bottom of that page, brainstorm some topic

sentences to start off your Background paragraph5. Number each term in the chart based on the order you

think you should introduce it in your Background paragraph

Your goal as a group is to help EVERYONE be ready to write an excellent Background Info paragraph!

Quiet Independent Work Time

Tasks to Work On:Continue writing your lab report (it is due Monday)Do tonight’s HW (book reading & questions)Conference w/ Dickson about past assignments or

help on the lab reportSmall groups will come to work w/ Dickson on the Do

Now from earlier this weekWork quietly and professionally Stay focused

on biology.No internet – it slows down everyone’s laptop!

Homework:Typed & completed lab report due Monday.Silent Do Now – On an index card, not in your

notebook! Find the following definitions in your notebook and write

them on an index card (all definitions on same card): Diffusion Osmosis Facilitated Diffusion Active Transport

Today’s Objective: Apply these vocabulary words to various situations in living things – so that you can accurately identify examples and pictures of each process.

Bio 9B: Friday12/16/11Title: Cell Membrane Vocabulary Application

Instructions

Spend 3 minutes at each station Read the scenario, look at the pictures,

read the questions Mark your answers on the answer sheet

(do not write on the station handouts) Work with your assigned partner (next

slide), talk quietly on with them, and stay focused on the work.

Partners

Justin—Jarred Ritshly—Kira Jenna—Skyeler—Tia Ronica--Naidaliz Sequoia—Steven—

DJ

Cabinet Side of the Room Window Side of the Room

Noah—Priscilla Nicole—Zak—Sara Destinee—Emily Aaron—Emperor Tracey-Natalie-

Elizabeth

Exit Ticket

Work silently on your own to correct or finish your Do Now sheet from Monday

If you don’t get your Do Now sheet back, complete the AP Biology test questions!

MOVEMENT ACROSS CELL MEMBRANES Biology 9B - Dickson.

Documents

cell slide

cell membrane controls

cell methods

cell membranes objectives

cell diffusion osmosis

outer membrane

cell membranes biology

diffusion lab slide