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AREA OF STUDY 1
1.0 Cells : basic units of life on earth
Pete Hamilton Sandringham College

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Cell Intro video
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The Cell Theory
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All living things are made up of one or more cells – cells are very small
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There can be different kinds of cells within living organisms.
(skin cells, brain cells, muscle cells)
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Cells are the functional unit of all living things
This means that they are where all the action happens, they process food, give structure and many other things.
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The Cell Theory
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All cells come from pre-existing cells.
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Cells and organisms vary greatly in size
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Single or multicelled?
Unicellular organisms
: composed of only 1 cell- Microscopic
Euglena 10 microns
Multicellular organisms: composed of many cells, cells specialised - Microscopic to
Macroscopic Hydra 10,000 microns
Units of measurement:
1 micrometer = 1 micron 1 μ m = 1 μ m
1 micrometer = 0.001 millimeter 1 μ m = 0.001 mm
1 micrometer = 0.0001 centimeter 1 μ m = 0.0001 cm
1 micrometer = 1.0 × 10 -6 meter 1 μ m = 1.0 × 10 -6 m
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Cells and Microscopes
There are several types of microscopes, each can allow us to view cells differently and to a different degree.
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Cell Structure
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There are many types of cells and each has its own structure and purpose.
each cell has features that help it carry out its purpose.
(e.g Nerve cells)
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Properties of cells
Despite cells having different functions, all cells have some things in common.
• Plasma or Cell membrane separates the cell from it’s external environment.
• Cytoplasm – Jelly like holds all the organelles, ions, salt, enzymes, nucleus and is 90% water. Cytosol is the fluid part of the cytoplasm.
• DNA- genetic material that directs the cell’s activities.
• Organelles – Components inside the cells cytoplasm that perform different functions.
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Prokaryotes Vs Eukaryotes
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PRO
More primitive cells
Lack membrane bound organelles
Smaller than Eukaryotic cells
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EU
Complex cells
Have membrane bound specialised organelles
Larger than prokaryotic cells
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Prokaryote cells simple cells (example: E. coli)
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 capsule : slimy outer coating cell wall : tougher middle layer cell membrane : delicate inner skin
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Prokaryote cells (example: E. coli)
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 cytoplasm : inner liquid filling
DNA in one big loop pilli : for sticking to things flagella : for swimming ribosomes : for building proteins
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Prokaryote lifestyle
 unicellular : all alone
 colony : forms a film
 filamentous : forms a chain of cells
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Prokaryote Feeding
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Photosynthetic : energy from sunlight
Chemosynthetic : energy from chemicals
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Prokaryote Feeding
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Disease-causing : feed on living things
Decomposers : feed on dead things
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Prokaryote
E. coli bacteria on the head of a steel pin.

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Eukaryotes
DNA is located inside the nucleus as thread like chromosomes
Specialised organelles each performing a specific function
Eukaryotes
Protists Fungi Animals Plants
* Mostly single celled but occasionally multicellular (seaweed)
* Very diverse- include moulds, algae, protozoan
* Some are unicellular but mostly they are multicellular
* Made of thread like filaments call hyphae
* Are heterotrophs
* Do not have flagella or cilia
* Multicellular organisms
* Highly Mobile
* Heterotrophic
* Multicellular
* Autotrophic
* Have a cell wall made of cellulose
*Large fluid filled vacuoles
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Eukaryotes are larger and more complex
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Have organelles
Have chromosomes can be multicellular include animal and plant cells
Animal cells Intro
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Organelles are membrane-bound cell parts
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Mini “organs” that have unique structures and functions
Located in cytoplasm
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Cell Structures
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Cell membrane delicate lipid and protein skin/membrane around cytoplasm found in all cells
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Nucleus a membrane-bound sac evolved to store the cell’s chromosomes
(DNA) has pores: holes
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Nucleolus inside nucleus location of ribosome factory
RNA
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 mitochondrion
Releases the cell’s energy the more energy the cell needs, the more mitochondria it has
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Mitochondria
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Mitochondria

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Ribosomes build proteins from amino acids in cytoplasm may be free-floating, or may be attached to ER made of RNA
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Endoplasmic reticulum may be smooth : builds lipids and carbohydrates may be rough : stores & transports proteins made by attached ribosomes
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Golgi Complex takes in sacs of raw material from ER sends out sacs containing finished cell products
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Golgi Apparatus

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Lysosomes sacs filled with digestive enzymes digest worn out cell parts digest food absorbed by cell
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Centrioles pair of bundled tubes organize cell division
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Cytoskeleton
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 made of microtubules found throughout cytoplasm gives shape to cell & moves organelles around inside.
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Cytoskeleton
 cytoplasmic streaming
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Structures found in plant cells
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Cell wall very strong made of cellulose protects cell from rupturing glued to other cells next door
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Vacuole huge water-filled sac keeps cell pressurized stores starch
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Chloroplasts filled with chlorophyll turn solar energy into food energy
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Chloroplasts
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How are plant and animal cells different?

Structure cell membrane nucleus nucleolus ribosomes
ER
Golgi centrioles cell wall mitochondria cholorplasts
One big vacuole
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Animal cells
Yes
Yes yes yes yes yes yes no yes no no yes
Plant cells yes yes yes yes yes yes no yes yes yes yes
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Advantages of each kind of cell architecture
Prokaryotes Eukaryotes simple and easy to grow fast reproduction all the same can specialize multicellularity can build large bodies
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Examples of specialized euk. cells
 liver cell: specialized to detoxify blood and store glucose as glycogen.

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 sperm cell: specialized to deliver
DNA to egg cell

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Mesophyll cell specialized to capture as much light as possible inside a leaf
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How do animal cells move?
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Some can crawl with pseudopods
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Some can swim with a flagellum
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Some can swim very fast with cilia

Pseudopods
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 means “fake feet” extensions of cell membrane example: amoeba
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Amoboid movement

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Flagellum/flagella large whiplike tail pushes or pulls cell through water can be single, or a pair
Cilia
 fine, hairlike extensions
 attached to cell membrane
 beat in unison
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Cilia & Flagella

Organelles
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Organelles
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Organic and Inorganic compounds
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Compounds are organized into 2 types:
Organic compounds – These are complex chemical compounds which contain
Carbon and Hydrogen.
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Inorganic compounds- These are all non-organic compounds. e.g. water, oxygen, nitrogen.
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Inorganic components
Water- most organisms are 70-90% water
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Surface tension
Heat capacity
Cohesiveness
Oxygen and carbon dioxide
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Oxygen is needed for cells to release energy from food molecules
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Carbon is the key molecule in organic molecules.
Nitrogen
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Nitrogen is needed to make proteins.
Minerals
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Are needed for the structural part of cells, the body and in enzymes and vitamins
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Organic molecules
Carbohydrates
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Important source of energy
Made of carbon, hydrogen and oxygen
Lipids
 fats and oils important for energy stores and some structures.
Proteins
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Vital for all sorts of functions!
Nucleic Acid
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Genetic material for all organisms
Vitamins
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Required for normal functioning.
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Eukaryotic Cells
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Eukaryotic Cells
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Eukaryotic Cells
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Tour of the cell Bozemanscience
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