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DO NOW … What four characteristics are common to
all living things?
What are cells?
Name different types of cells you know of...
What is a difference between living and non-living things?
Objectives
Describe how cells were discovered and named.
Identify the scientists that discovered and observed cells.
List the 3 parts of the cell theory.
What is a cell?
Basic structural and functional unit of all living organisms!
They come in different shapes + sizes
Who discovered the cell?
ROBERT HOOKE
Observed dead cork cells
Said boxes looked like tiny rooms or jail “cells”.
Used a microscope at 30x magnification
Who else discovered the cell?
ANTON VAN LEEUWENHOEK
Observed pond water
1st to observe “living” cells
Used a microscope at 300x magnification
Fransisco Redi Experiment
Placed meat in both an open container and a closed container to see what happened.
Redi’s Conclusion
Maggots come from flies, NOT the meat!
Life must come from life, which proved that spontaneous generation is not real!
People still did not believe him but he was right.
Louis Pasteur Conclusions
Discovered that cells MUST come from other cells
Disproved “Spontaneous Generation” and said life cannot just appear out of no where.
Helped verify Redi’s research!
Pasteurization
Pasteur came up with the idea of Pasteurization after discovering bacteria could contaminate milk from the air.
This process kills the bacteria so that it does not harm us!
Used in milk, cheese, yogurt, etc.
http://bcs.whfreeman.com/thelifewire/content/chp03/0302003.html
Cell Theory = Every living thing is made of one or
more cells Cells carry out the functions needed
to support life Cells come only from other living
cells
Do Now
What are the differences between prokaryotic and eukaryotic cells?
Why do we need so many more organelles than bacteria do? Explain.
Objectives
Compare and contrast a scanning electron microscope vs. a transmission electron microscope.
Describe prokaryotic and eukaryotic cells.
Section 1.2 - Microscopes
How small are cells?
Unit used = micrometer (um)
One millionth of a meter
Most cells range from 1 um to 1000
um.
Light Microscope
Uses light
Looks at thin specimen
Total Magnification = 40x-100x
Use to see cells, but not detailed organelles
SEM vs. TEM
SEM “Scanning electron microscope”
Beams of electrons bounce of the surface of the coated cell.
Images appear 3D- Outside Specimen
Total Magnification = 100,000x
Must be dead . Specimen coated in metal
TEM “Transmission electron
microscope”
Electrons pass through the think section.
Images appear 2D
Total Magnification = 300,000x
Allows us to see organelles inside the cell
Prokaryotic Cells
Have circular DNA
NO nucleus
Does not have membrane bound organelles ex: snow globe
Most unicellular organisms are prokaryotes
Example: Bacteria
Eukaryotic Cells
Have linear DNA – double helix shape
Has nucleus
Have membrane bound organelles
Most multicellular organisms are eukaryotic cells. Some are unicellular though.
Example: You!
Do Now
What is found INSIDE a cell?
Do plant cells and animal cells have the same stuff inside?
What do plants need to do that animals do not?
Objective
To compare and contrast animal vs. plant cells.
Identify each organelle in a diagram of a cell.
Explain the function of each organelle
To create flash cards for the next test
CELL ORGANELLES
Nucleus
Endoplasmic reticulum
Vesicle
Golgi apparatus All have specific
Lysosome functions!
Mitochondrion
Chloroplast
Central vacuole
THE WALL – protects the internal structures of the cell.
Selective permeability -Determines what comes in and out of the cell
A.K.A- Cell Membrane!
Plasma Membrane
Cytoplasm/Cytoskeleton
Cytoplasm- Clear FLUID that contains the organelles.
Cytoskeleton- Provides the FRAMEWORK for the cell, holds organelles in place.
Nucleus
Nucleus- CONTROLS the cell
Nucleolus- produces ribosomes
Nuclear Pores- Allows things in and out of the nucleus.
Challenge Question
Where do you find the DNA or a eukaryotic cell?
If prokaryotes do not have a nucleus, where is their DNA?
Endoplasmic Reticulum
Rough- Contains ribosomes and synthesizes PROTEINS
Smooth- No Ribosomes, synthesizes LIPIDS (fats)
Cilia and Flagella
Flagella- Used in cells for movement
Cilia- Used in stationary cells for moving substances around the outside of the cell.
Mitochondria
Convert oxygen into ENERGY (ATP)
(we will talk about this more when we do cellular respiration!!)
Central Vacuole
LARGE WATER “bubble” in the plant cell
Maintains the SHAPE of the cell, without it, the plant cell would shrink and the plant would wilt
Stores water, along with ions, nutrients, and waste.
Cell Wall
Supports the cell and maintains its shape
Works with central vacuole to maintain “Turgor Pressure”
Challenge Question!
How can chloroplast, a structure found in plant cells but not in animal cells, provide energy for both plants and animals?
Endosymbiotic Theory
explains the origin of chloroplasts and mitochondria and their double membranes.
Theory: Chloroplasts and Mitochondria were once prokaryotes that were engulfed!!
Theory = Evidence!!
•Have circular DNA like bacteria•Replicates(reproduces) like bacteria separate from the host cell•Make their own proteins•Two membranes (one from the host cell and one from their own cell membrane)
Objectives
Compare and contrast the 3 Domains.
Understand multicellular organization.
Explain the significance of models in science.
Section 1.3 - Domains
3 domains of life: Eukarya – Have a
nucleus. Plants, animals, and fungi.
Bacteria – prokaryotics.
Archaea – “ancient”. Genetically different from bacteria.
Specialization
•Specific cells perform specific functions.
Ex: Blood cells can only be blood cells. Muscle cells cannot be turned into blood cells.
Organization
Organisms are organized:
Cells Tissue Organ Organ System Organism
Plants are Organized too!
Organs Stems Roots Leaves
Tissue and organs
Tissue – group of similar cells that are organized to do a specific job.
Organ – different tissues working together to perform a particular function.
Scientists use models to study cells!
Build models to study small parts. A. How could YOU creatively build a 3-D model of a cell?
B. How would you represent DNA? Rosalind Franklin – used x-rays to produce images of DNAWatson and Crick – put together a 3D model of DNA with
sticks and present it to the world in 1953 (Now it could be done with computers)
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