chapter 7 notes n.
Skip this Video
Download Presentation
Chapter 7 Notes

Loading in 2 Seconds...

play fullscreen
1 / 23

Chapter 7 Notes - PowerPoint PPT Presentation

  • Uploaded on

Chapter 7 Notes . Cell Structure and Function. Cells and Cell Theory. Cell: the basic unit of all forms of life History Robert Hooke (1665) - described the empty chambers of cork as “cells”. 2. Matthias Schleiden (1838) - all plants are made of cells

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about 'Chapter 7 Notes' - dobry

Download Now An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
chapter 7 notes

Chapter 7 Notes

Cell Structure and Function

cells and cell theory
Cells and Cell Theory
  • Cell: the basic unit of all forms of life
  • History
    • Robert Hooke (1665)

- described the empty chambers of cork as “cells”

2. Matthias Schleiden (1838)

- all plants are made of cells

3. Theodor Schwann (1839)

- all animals are made of cells

4. Rudolph Virchow (1855)

- all cells come from preexisting cells

** before this, people believed in spontaneous generation

Cell Theory

1. All living things are composed of 1 or more cells

2. Cells are the basic units of life

3. All cells come from preexisting cells

** exception: viruses?

ii prokaryotes and eukaryotes
II. Prokaryotes and Eukaryotes
  • Prokaryotic cells do not have nuclei

- example: all bacteria

  • Eukaryotic cells have nuclei and organelles

- example: plants, animals, fungi

iii cell structures
III. Cell Structures
  • Cytoplasm: everything between the membrane and nucleus

1. Structure

a. Cytosol: jelly-like mixture consisting of water, proteins, carbohydrates, and other organic compounds

b. Organelles: structures that work like miniature organs, carrying out specific functions in the cell (suspended in the cytosol)

2. Function

a. Biological reactions take place in the cytosol

b. Organelles each have specific jobs within the cell

3. Analogy

- like the body of a person

organelles = organs

cytosol = everything surrounding organs

iv cell shape and size
IV. Cell Shape and Size
  • Maintenance of shape

1. In plants: cell wall

2. In animals: cytoskeleton

  • Cytoskeleton

- consists of 2 types of structures

1. Microtubules: hollow tubes made of tubulin

a. Cilia: short, hair-like projections

b. Flagella: long, whip-like projections

2. Microfilaments: NOT hollow – 2 twisted chains of proteins (like a rope)
  • Size of Cells

- can vary from 1 micrometer (bacteria) to 1 meter (nerve cell)

movement through the membrane
Movement through the Membrane
  • The cell membrane is semipermeable

- only certain molecules can get through

  • Passive transport: no energy required

1. Diffusion: the movement of molecules from a region of high concentration to a region of low concentration

- continues until equilibrium is reached (equal concentrations on both sides of membrane)
- temperature affects diffusion:

higher = faster

- size of particles affects diffusion:

smaller = faster


97% water

100% water

2. Osmosis: the diffusion of water across a membrane from high water concentration to low water concentration

Which way will the water move?


97% water

90% water

Which way will the water move?


95% water

95% water

90% water

98% water

This solution is hypertonic

- water diffuses out of the cell

This solution is hypotonic

- water diffuses

into the cell


95% water

95% water

This solution is isotonic

- no net change

3. Facilitated diffusion: uses protein channels to move molecules from high concentration to low concentration
  • Active Transport: energy required

1. Carrier proteins may act as pumps

-example: sodium-potassium pump

a. Cells continually pump potassium ions into the cell, and sodium ions out



  • Important for muscle contraction and nerve impulse transmission


a. Pinocytosis: membrane encloses a fluid droplet and brings it inside the cell

b. Phagocytosis: membrane encloses a large particle and brings it inside the cell

3. Exocytosis: materials move outside the cell

- wastes and cell products may leave the cell this way