discovery of cells, microscopes and parts of cells/functions 7.1 and 7.2 notes

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.