Transcript cell unit part 1

Chapter 7 “Cell Structure &
Functions” Objectives
Students will learn about cell theory and
the scientists who discovered it.
 Students will also learn about the
structure of a cell and its organelles,
important cellular functions and the
basic organization of cells into a living
organism.

Microscope Handling
1.
2.
3.
4.
5.
Carry microscope properly having one
hand beneath the base and the other
hand grasping the arm
Place arm of microscope facing you
Move objectives all the way up
Rotate and lock (clicking sound) low
power objective into position.
Turn on the light
6.
7.
8.
9.
Place slide onto stage, use stage clips to hold
slide in place (make sure that the specimen is
centered)
Move low power objective lens, using the
course adjustment knob, until almost touching
the slide.
Now, looking through the ocular lens, move
the objective (10X) until the image is in focus
Switch to high power carefully, rotate and lock
into place. Use only the fine-adjustment knob,
because you could damage or break the slide
Discovery of Cells
1600s Anton von
Leeuwenhoek - 1st
person to observe &
describe
microorganisms & living
cells.
 1st person to construct
a microscope to view
microorganisms

Robert Hooke


Robert Hooke 1600s
observed dead plant
cells from cork.
In fact, it was Hooke
who coined the term
"cells": the box-like
cells of cork reminded
him of the cells of a
monastery.
1833 Robert Brown
 Observed
that
many cells to
have a dark
structure near the
center of a cell.
We now call this
structure a
nucleus
1838 Matthias Scheleiden
 German
botanist
 Studied plants &
concluded that all
plants are made
of cells.
1839 Theodor Schwann
a German
cytologist and
physiologist
 Concluded that all
animals are made
up of cells.

1855 Rudolf Virchow
 Researched
and
concluded that all
cells arise from
preexisting cells
 example: skin
cells develop into
new skin cells.
Cell Theory


1.
2.
3.
The combined work of these
scientists developed what
we know today as the Cell
Theory.
The cell theory states:
all living things are
composed of cells.
cells are the basic unit of
structure and function in
living things
all cells come from
preexisting cells.
1970 Lynn Margulis


Proposed the idea that
certain organelles were
once free-living cells
themselves.
Ex: Chloroplasts were
once free-living
photosynthetic bacteria
that were incorporated
into plant cells and
formed a symbiotic
relationship.