discovery of cells, microscopes and parts of cells/functions 7.1 and 7.2 notes
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DISCOVERY OF CELLS, MICROSCOPES AND PARTS OF CELLS/FUNCTIONS
7.1 and 7.2 notes
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. Cellstissuesorgansorgan
systemsorganism
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) Body Tube2) Nosepiece3) Scanning Objective 4x4) Low Power Objective
10x5) High Power Objective
40x6) Stageclips7) Diaphragm
8) Light9) Eyepiece 10x10) Arm11) Stage12) Coarse
Adjustment13) Fine Adjustment14) 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 XExtremely condensed
genetic info.DNA:Genetic blueprint and has
plans for making proteinsDouble HelixChromatinLooks 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 non-studded is the smooth.
Endoplasmic Reticulum Function
Rough Endoplasmic Reticulum (RER)
Fluid filled tunnelsStudded with ribosomesArea of protein production.Smooth Endoplasmic
Reticulum (SER)Fluid filled tunnelWhere 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 microtubulesHelp to move an
object (transportation)
Cilia moves by a wave motion
Flagella moves by a whip-like 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 shapedGreen 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/SupportKeeps cell shape
Path of a protein
1. Amino acids are linked together to form proteins on ribosomes (on the RER).
2. Protein travels along the RER then it buds off in a vesicle.
3. Vesicle goes to golgi apparatus.4. Protein gets modified for what it is going to be
used for in the cell.5. The modified protein is shipped from the golgi
apparatus in a vesicle.6. The vesicle either leaves the cell or is used
within the cell.