Aim: How has the electron microscope enabled scientists to see the unseen?

Living Environment HW#10Due Friday 10/8

• Read text pages 184-189

• Pg 186 word origins – answer question

• Pg 186 draw diagram –answer predicting question under fig. 7-18

• Read – How does penicillin work? Summarize and come up with two questions for further research.

Differences between compound, and electron microscopes

Difference in images

The cell membrane helps the cell maintain Homeostasis

Lipid bilayer

Structure of the cell membrane

Outsideof cell

Insideof cell(cytoplasm)

proteinsCell membrane

Protein channel

Lipid bilayer

Carbohydrate

antibiotics that interfere with cell wall synthesis have a high specificity and are low in toxicity to host

organisms

Tagged carbohydrate on the surface of the cell membrane

Aim: How do substances diffuse through a membrane?

Things that move into a cell…

Things that move out of a cell…

Diffusion – molecules of a substance move from areas of higher concentration to areas

of lower concentration

Water molecules

Sugar molecules

Facilitated diffusion

Outsideof cell

Insideof cell(cytoplasm)

proteinsCell membrane

Protein channel

Lipid bilayer

Carbohydrate

Active Transport requires energy

A

B

A molecule is moving across the cell membrane from an area of low concentration with the help of a transport protein

Large molecules pass through the cell membrane by endocytosis and exocytosis

Do Now Summary

Plasma Membranes are Selectively Permeable

• What does this mean?

• What are the ways in which substances can pass through a cell membrane