Transcript 7.1 and 7.2 notes

7.1 and 7.2 notes
DISCOVERY OF CELLS, MICROSCOPES AND
PARTS OF CELLS/FUNCTIONS
The Discovery of Cells
 Before the microscope, scientists were not able to
view cells. They thought that diseases were caused
by spirits but in reality they were caused by bacteria
& viruses.
 The cell is the basic unit of structure and function
of all living things.
 Cells help to carry out life processes.
Microscopes and the History of the Cell Theory
 In the 1500’s eyeglass
makers are working on
lenses.
 1600s Janssen - Made
the first microscope
lens. Magnification
10X- like a basic
“magnifying lens”. This
was the 1st compound
microscope.
Microscopes and the History of the Cell Theory
 First microscope was used by Anton van
Leewenhoek. Called a simple light
microscope.
 1665- Anton van Leeuwenhoek studied pond
water. Observed “animalcules” or single celled
organisms.
Microscopes and the History of the Cell Theory
 Hooke - used the
microscope to view
cork. Called the little
boxes “cells” which
means little “rooms” in
Latin. Reminded him
of the rooms monks
lived in-“cellules”. He
used an early
compound light
microscope.
Microscopes and the History of the Cell Theory
 Compound light
microscope was invented.
 Uses light AND lenses
which helped with
magnifying things in steps.
 Was able to magnify up to
1500X. We use objectives
that magnify only up to 400
X . (Scanning, low, high
powers are what we will
use.) OIL- 1000x (we will
not use this)
Microscopes and the History of the Cell Theory
 1830s- Schleiden observed plants and said that
they were made up of tiny units (wet grass)plants are made up of cells.
 Schwann - (“swan”) observed animal tissue and
stated that cells were the building blocks of
animals in addition to plants.
Microscopes and the History of the Cell Theory
 Virchow - stated that
cells are produced by
other living cells.
 Identified the nucleus
and said that it was
responsible for cell
division.
The Cell Theory
 All living things are composed of one or more cells.
Ex. Amoeba = 1 cell= unicellular and eukaryotic
(eukaryotic means it has a nucleus)
Ex. Humans= multicellular
The Cell Theory
 *The cell is the basic unit of structure and
organization/function of organisms.
 All cells have different functions!
Ex. Cellstissuesorgansorgan systemsorganism
The Cell Theory
 All cells come from preexisting cells.
Ex. Cut skin heals quickly because skin cells divide.
Electron Microscopes – 1930s/1940s
 Resolution - How clear
an image is.
 Electrons are used to
illuminate an object
rather than light;
Magnify up to 106 (which is 1
million)
 Electron microscope
Transmission Electron Microscopes
 Transmission Electron Microscope (TEM) electrons sent through a thin slice of a specimen.
 Shows a cross section.
 2-Dimensional.
 NO LIVING SPECIMENS
Scanning Electron Microscopes
 Scanning Electron Microscope (SEM) bounces electrons off the surface of a specimen.
 SOMETIMES LIVING,
 GIVES 3-Dimensional APPREARANCE
Prokaryotes vs. Eukaryotes
 1) prokaryotes are simple
cells with no defined
nucleus. Ex: bacteria
- They DO have genetic
material it just isn’t
contained in one area.
Prokaryotes vs. Eukaryotes
 2) Eukaryotes are complex cells with a defined
nucleus. Ex: animal and plant cells
 Animal Cells:DO NOT have cell walls
 Plant Cells: Do have cell walls
Compound light microscope parts
Microscope parts by number
1)
2)
3)
4)
5)
6)
7)
Body Tube
Nosepiece
Scanning Objective 4x
Low Power Objective 10x
High Power Objective 40x
Stageclips
Diaphragm
8) Light
9) Eyepiece 10x
10) Arm
11) Stage
12) Coarse Adjustment
13) Fine Adjustment
14) Base
Microscope parts quiz
 In three school days there will be a quiz
that looks identical to the fill in the blank
image worth 18 points.
 1 pt for correct part and 1 pt for correct
magnifications.
 Spelling does count (-1/2 pt for wrong
spelling)
What the parts do!
 Eyepiece: Contains a magnifying lens with a
magnification of 10x
 Arm: Supports the body tube
 Stage: Supports the slide being observed
 Fine Adjustment: Moves the body tube slightly to
adjust the image (can be used with all lenses)
What the parts do!
 Coarse Adjustment: Moves the body tube to focus
the image in LARGE movements (only to be used
with scanning objective and low power).
 Base: Supports the microscope
 Diaphragm: Regulates the amount of light passing
up toward the eyepiece.
 Stage clips: Holds the slide in place
What the parts do!
 High power objective: Provides a magnification of
40x
 Low power objective: Provides a magnification of
10x
 Scanning power objective: provides a
magnification of 4x
What the parts do!
 Nosepiece: Holds the objectives and can be
rotated to change the magnification.
 Body Tube: Maintains the proper distance
between the eyepiece and the objectives
Determining TOTAL magnification
 Eyepiece x Objective = Total Magnification
Try finding the total magnification for all three
objectives in our microscopes.
Rules! Rules! Rules!
You break the microscope you BUY the microscope…
so rather than having to shell out hundreds to
thousands of dollars to replace it follow the rules.
Take a couple of minutes and READ the rules.
7.2 Cell Parts and Functions
Cell Membrane / Plasma Membrane
 Prokaryote or
Eukaryote? Both
 Location: Outside edge
of the cell.
 Also known as the
phospholipid bilayer
Cell Membrane / Plasma Membrane Function:
 Controls what enters and
leaves the cell.
 Has a double layer with
hydrophilic heads
outside and hydrophobic
tails inside.
 Items can move in and
out through protein
channels.
 NOT a cell wall
Cytoplasm
 Prokaryote or
Eukaryote? Both
 Location: Fills the spaces
inside the cell.
Cytoplasm Function:
 Made up of a jelly-like
water.
 Organelles reside in the
cytoplasm
 2/3 of a cell is water, that
water is in the cytoplasm
Nucleus
 Prokaryote or
Eukaryote? Eukaryote
 Location: Inside the cell
Nucleus Function
 Directs cell activities
 Contains the cell’s DNA
(protects the DNA from
being damaged)
 Is only visible when cell is
not dividing
Nuclear Membrane
 Prokaryote or
Eukaryote? Eukaryote
 Location: The shell that
surrounds the nucleus
with the “dimples” in it.
Nuclear Membrane
Function:
 Allows materials the
enter/leave the nucleus
through the pores
(dimples).
Nucleolus
 Prokaryote or
Eukaryote? Eukaryote
 Location: In the nucleus
Nucleolus Function
 Produces ribosomes
Chromosomes/DNA/Chromatin
 Prokaryote or
Eukaryote? Both
 Location: In the nucleus
for a eukaryote, in the
cytoplasm for a
prokaryote.
Chromosomes/DNA/Chromatin Function
Chromosome:
 Looks like an X
 Extremely condensed genetic
info.
DNA:
 Genetic blueprint and has
plans for making proteins
 Double Helix
Chromatin
 Looks like silly string
 Uncoiled DNA inside nucleus
Ribosomes (the black dots)
 Prokaryote or
Eukaryote? Both
 Location: In the
cytoplasm (prokaryotes)
or on the endoplasmic
reticulum (eukaryotes).
Ribosomes Function
 Protein factories
 Made up of RNA
Endoplasmic Reticulum (smooth and rough)
 Prokaryote or
Eukaryote? Eukaryote
 Location: Located in the
cell usually around the
area of the nucleus due
to ribosomes being
created in the nucleus.
Note: the studded is the
rough and the nonstudded is the smooth.
Endoplasmic Reticulum Function
Rough Endoplasmic
Reticulum (RER)
 Fluid filled tunnels
 Studded with ribosomes
 Area of protein production.
Smooth Endoplasmic
Reticulum (SER)
 Fluid filled tunnel
 Where lipids and carb. are
produced.
 Helps with muscle
contractions.
Golgi Bodies/Golgi Apparatus/Golgi Complex
 Prokaryote or
Eukaryote? Eukaryote
 Location: Located
outside of the nucleus
around the cell.
Golgi Bodies/Golgi Apparatus/Golgi Complex
Function
 Looks like stacks of pita.
 Sorts, modifies, and
packages proteins made
in the RER.
 Then it ships proteins
around the cell in
vesicles (bubbles).
Mitochondria
 Prokaryote or
Eukaryote? Eukaryote
 Location: Located
outside of the nucleus
around the cell.
 Cool fact… can contain
its own DNA
Mitochondria Function
 The powerhouse or
engine of the cell.
 Has a double membrane
with the inner folded to
increase surface area and
therefore energy
production.
 Releases energy stored in
food (chemical energy)
through cellular
respiration
Cytoskeleton (microtubules and microfilaments)
 Prokaryote or
Eukaryote? Eukaryote
 Location: Located all
over the cell
 This is NOT a cell wall.
Cytoskeleton Function
 Made of hollow tubes of
proteins
 Helps with keeping
shape and keeping
organelles in place.
 Can be used as a path for
things to travel along.
 Helps with cell division
Vacuole
 Prokaryote or
Eukaryote? Eukaryote
 Location:
Animal cells have many
small ones all over.
Plant cells have one large
central vacuole and many
smaller spread
throughout.
Vacuole Function
 Many small ones spread
throughout cell for water,
waste, or food storage.
 In a plant cell the central
vacuole holds water and
allows the cell to keep its
shape.
Lysosomes (or peroxisomes)
 Prokaryote or
Eukaryote? Eukaryote
 Location: spread
throughout the cell.
Lysosomes (or peroxisomes) Functions
 A bag of enzymes
 Responsible for speeding
up the breakdown of
large food particles,
macromolecules, waste,
and even if need be other
worn out cells.
Centrioles
 Prokaryote or
Eukaryote? Eukaryote
 Location: usually located
near the nucleus
Centrioles Function
 Large bundle of protein
tubules
 Helps with cell division
 Helps to organize the cell
Flagella or Cilia
 Flagella
 Cilia
Flagella or Cilia
 Prokaryote or
Eukaryote? Eukaryote
 Location: on the outside
of a cell
 Not all cells have this
Flagella or Cilia Function
 Made of microtubules
 Help to move an object
(transportation)
Cilia moves by a wave
motion
Flagella moves by a whiplike motion
Chloroplasts (Plastids)
 Prokaryote or
Eukaryote? Eukaryote
 Location: around the cell
Chloroplasts (Plastids) Function
 Runs photosynthesis by
trapping solar energy
(light) and changing it
into glucose (chemical
energy).
 Oval shaped
 Green due to the pigment
chlorophyll.
 Can contain DNA
Cell Wall
 Prokaryote or
Eukaryote? Eukaryote
 Location: around the
outside edge of the cell
Cell Wall Function
 Very rigid structure
made of cellulose
(complex carb.)
 Keeps extra water out of
plant cells.
 Protection/Support
 Keeps cell shape
Path of a protein
1.
2.
3.
4.
5.
6.
Amino acids are linked together to form proteins on
ribosomes (on the RER).
Protein travels along the RER then it buds off in a
vesicle.
Vesicle goes to golgi apparatus.
Protein gets modified for what it is going to be used for
in the cell.
The modified protein is shipped from the golgi
apparatus in a vesicle.
The vesicle either leaves the cell or is used within the
cell.