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Chapter 3

Cellular Structure and Function

Section 1 - Introduction to Cells

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The Cell!

Smallest living unit

We can see cells using a

But, if we use an electron microscope we can see MUCH more!

Worlds Most Powerful Microscope Video

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Organelles - Tiny structures within cells

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Inner Parts of a Cell

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Who saw cells first?

1665 - Robert Hooke

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Soon after, Anton van Leeuwenhoek saw bacteria

Rotifer

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The Cell Theory

States 3 things:

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Why are cells so tiny?

Area to Volume ratio

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Cells have specialized shapes

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ALL cells have:

Plasma (cell) membrane

Cytoplasm

Ribosomes

DNA

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Two broad types of cells

Prokaryotic EukaryoticNo nucleus

No "membrane bound" organelles

Nucleus

Many organelles

Smaller Larger

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1 Tiny structures that make up cells are called

A Organs

B Nucleus

C Organelles

D Sub-units

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2 Which type of microscope allowed us to see organelles inside of cells?

A Light Microscope

B Electron Microscope

C Sonic Microscope

D Telescope

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3 Which two of the following are characteristics of prokaryotic cells?

A Nucleus

B No Nucleus

C Organelles

D No "membrane bound" organelles

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Where does this leave viruses?

Virus = Protein + DNA

No plasma membrane, ribosomes, cytoplasm = Not a cell

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Section 2

Cell Structures

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Plasma Membrane

"wall"

made of lipids

semipermeable

Typical Eukaryotic Cell Parts

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Plasma Membrane

Other molecules are embedded in the membrane

Proteins - Act as passageways

Cholesterol - Strengthens

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Cytosol

water + other molecules

cytosol + organelles = cytoplasm

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Nucleus

Contains DNA

Chromosomes - X shaped, DNA wrapped around proteins

DNA has "instructions" to make proteins

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Ribosomes

Produces rough proteins

"Factory"

Ribosomes are produces in the nucleolus

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Endoplasmic Reticulum

Rough ER vs Smooth ER

Transports products

"Highway"

Proteins Lipids

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Golgi apparatus

"Refinery"

Finishes proteins

Ships them to destination in vesicles

"Post Office"

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Lysosome

Breaks down old molecules & defective proteins

"Scrapyard"

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Mitochondria

Produce energy (ATP) from food

"Powerplant"

Endosymbiosis

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Cytoskeleton

Gives shape and strength to cell

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Flagella - tail-like structure

Cilia - hair-like structures

Movement

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Centrioles

Involved in cell reproduction

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4 The "brain" of the cell is the

A Endoplasmic Reticulum

B Ribosomes

C Nucleus

D Plasma Membrane

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5 Which organelle produces proteins? (is like a factory)

A Endoplasmic Reticulum

B Ribosomes

C Nucleus

D Plasma Membrane

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6 Which organelle provides energy for the cell?

A Nucleus

B Mitochondria

C Golgi apparatus

D Lysosome

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Special Plant Organelles

Cell Wall

Strength & Protection

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Vacuole

Stores water and nutrients

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Plastids

Location of photosynthesis

3 types

Chloroplasts

Chromoplasts

Leucoplasts

Make and store pigments

Store starch

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Section 3

Cell Transport and Homeostasis

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Cells need to move things in and out

Passive TransportNo energy

more concentrated less concentrated

3 Types

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Diffusion

usually small, neutral molecules (O2, CO2)

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Osmosis

Special type of diffusion - referring to water

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Hypertonic Solution - More solutes than cell

Hypotonic Solution - Less solutes than cell

Isotonic Solution - Same

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Facilitated Diffusion

No energy, but special passageways are required

Larger molecules (H2O, C6H12O6)

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Active Transport

Against "concentration gradient" (low to high)

Energy required (ATP)

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Sodium-potassium Pump

Na+ pumped out, K+ pumped in

Important in muscle contractions and neuron activity

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Vesicle Transport

Very large molecules (proteins)

Endocytosis - Bringing into cell

Exocytosis - Out of cell

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7 If a cell is placed into a solution and the cell shrinks, then the solution must be a __________ solution.

A Hypotonic

B Isotonic

C Hypertonic

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8 The movement of water molecules across a semipermeable membrane is called

A Diffusion

B Facilitated Diffusion

C Active Transport

D Osmosis

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9 The picture below represents hydrogen ions being pumped "against the concentration gradient". This is an example of

A Diffusion

B Facilitated Diffusion

C Active Transport

D Osmosis