11/18 Biology update and homework due 12/2

 Hi folks,

First off NO CLASS next week due to  the Thanksgiving Break.  Here's wishing you all a safe and tasty Thanksgiving holiday.  Be sure to count all the biological molecules you'll be consuming in the turkey, potatoes and stuffing!!

By the way, take a look at this game if you have a chance.  It's quite a bit of fun and really helps get to know quite a few complicated systems that keep cells healthy.  https://www.kongregate.com/games/cellcraft/cellcraft

Be sure to get me any missing homework!  Email me if you're not sure if or what you're missing.

This week we learned about passive and active transport and diffusion and osmosis. 

Homework due next class is to:

Read Chapter 5 pages 96 - 106

answer questions 5-15 on page 108

Also, Answer the following questions.  (Be sure to check yourself with the answers below.)

1.  Why is active transport important to the cell?

2.  What is the definition of diffusion?

3.  What is the definition of a concentration gradient?

4.  What is the definition of osmosis?

5.  Do materials flow from low to high concentration or from high to low concentration?

6.  What is the definition of hypertonic solution?

7.  What is the definition of hypotonic solution?

8.  With today's potatoes, when they were in the salt solution, were they in a hyper or hypotonic solution?

9.  With today's potatoes, when they were just in water, were they in a hyper or hypotonic solution?

10.  When the potatoes were in the salt, did they swell or shrink?  Why?

11 When the potatoes were in the water, did they swell or shrink?  Why?

12.  Does water tend to flow towards solutes or away from solutes?

13.  Draw a picture of a cell in a hypotonic solution.  Be sure to label where the concentration of solutes is greater and whether water is entering the cell or moving out.

14. Draw a picture of a cell in a hypertonic solution.  Be sure to label where the concentration of solutes is greater and whether water is entering the cell or moving out.

Answers:

1.  It is a way that cells can get nutrients in and waste out.  it's important because many molecules are too large to pass through the cell membrane and because sometime you need to move things agains the concentration gradient. 

2.  Materials spreading out along a concentration gradient.

3.  Things tend to flow from a high concentration gradient to a low concentration gradient.

4.  Diffusion through a membrane.

5.  They flow from high to low naturally.  It takes energy to make them flow the other way.

6.  A solution where the concentration of solutes are high.

7.  A solution where the concentration of solutes are low.

8.  They were in a hypertonic solution.

9.  They were in a hypotonic solution.

10.  They shrank because the water left the cells to go towards the highly concentrated salt.

11.  They swelled because the water in the glass moved into the cells since the concentration of solutes was higher in the cells.

12.  Flows towards solutes.

13 and 14 see pic below.