CellsCells

Cells and their HistoryCells and their History All living things are made of cellsAll living things are made of cells Cells are microscopicCells are microscopic

Unicellular OrganismsUnicellular Organisms Just one cellJust one cell Can still perform functions necessary Can still perform functions necessary

for lifefor life

History of the discovery of cellsHistory of the discovery of cells 1. Robert Hooke observed dead cork 1. Robert Hooke observed dead cork

cells under a simple microscope in cells under a simple microscope in 16651665

2. 1838 Schleiden – proposed plant 2. 1838 Schleiden – proposed plant tissues are composed of cellstissues are composed of cells

3. 1839 Schwann – proposed animal 3. 1839 Schwann – proposed animal tissues are composed of cellstissues are composed of cells

4. 1858 – Cells come from pre-4. 1858 – Cells come from pre-existing cellsexisting cells

Cell TheoryCell Theory Developed from observations of Developed from observations of

Hooke, Schleliden, Schwann and Hooke, Schleliden, Schwann and VirchowVirchow

1. all living things are composed of 1. all living things are composed of cellscells

2. the chemical reactions which 2. the chemical reactions which occur in organisms occur in cellsoccur in organisms occur in cells

3. cells come from pre-existing cells3. cells come from pre-existing cells

Characteristics of all Living ThingsCharacteristics of all Living Things

1. Greater organization than non-1. Greater organization than non-living thingsliving things

2. Reproduce2. Reproduce 3. Grow3. Grow 4. Respond to stimuli/changes in 4. Respond to stimuli/changes in

environment.environment. 5. Homeostatic – try to keep internal 5. Homeostatic – try to keep internal

environment unchangedenvironment unchanged * Must meet all 5 to be alive!* Must meet all 5 to be alive!

How Cells WorkHow Cells Work Cell OrganellesCell Organelles 1. structures within cells that 1. structures within cells that

perform specific functions (like perform specific functions (like organs in animals and humans)organs in animals and humans)

2. 2. CytoplasmCytoplasm is jelly like solution in is jelly like solution in cells where the organelles floatcells where the organelles float

Cell ProcessesCell Processes 1. cells must have ways of eating, 1. cells must have ways of eating,

breathing and reproducingbreathing and reproducing 2. process are the basis for the 2. process are the basis for the

corresponding processes in large corresponding processes in large organismsorganisms

Eating = sugar getting to cells for Eating = sugar getting to cells for cellular respirationcellular respiration

DNADNA DeoxyriboNucleic AcidDeoxyriboNucleic Acid Long molecule which directs Long molecule which directs proteins production cellsproteins production cells Proteins affect cell processes Proteins affect cell processes and how they performand how they perform

Vocab to KnowVocab to Know Aerobe, Anaerobe, Autotroph, Cell Aerobe, Anaerobe, Autotroph, Cell

Cytology, Cytoplasm, Eukaryote, Cytology, Cytoplasm, Eukaryote, DNA, Heterotroph, Organelle, DNA, Heterotroph, Organelle, Prokaryote, UnicellularProkaryote, Unicellular

Types of Unicellular OrganismsTypes of Unicellular Organisms ProkaryotesProkaryotes 1. AKA bacteria1. AKA bacteria 2. evolved before more complex 2. evolved before more complex

class of organisms- eukaryotesclass of organisms- eukaryotes 3. Do not have membrane bound 3. Do not have membrane bound

organellesorganelles 4. DNA is arranged in a circular 4. DNA is arranged in a circular

shape shape

Prokaryotic CellsProkaryotic Cells

Types of Unicellular OrganismsTypes of Unicellular Organisms EukaryotesEukaryotes 1. more complex than prokaryotes 1. more complex than prokaryotes

because they have membrane bound because they have membrane bound organellesorganelles

2. DNA is linear 2. DNA is linear

Types of Unicellular OrganismsTypes of Unicellular Organisms Prokaryotes vs. EukaryotesProkaryotes vs. Eukaryotes Have the following parts in common Have the following parts in common

with Eukaryoteswith Eukaryotes 1. Cell membrane1. Cell membrane 2. DNA material2. DNA material 3. Ribosomes3. Ribosomes 4. Cytoplasm4. Cytoplasm

Eukaryotic CellsEukaryotic Cells

Types of Unicellular OrganismsTypes of Unicellular Organisms Heterotrophs vs. AutotrophsHeterotrophs vs. Autotrophs Get food from elsewhere vs. make Get food from elsewhere vs. make

own foodown food

Aerobes vs. AnaerobesAerobes vs. Anaerobes Organisms that require oxygen vs. Organisms that require oxygen vs.

organisms which don’t need oxygenorganisms which don’t need oxygen