AP Biology 2007-2008

Tour of the Cell (1)

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Prokaryote bacteria cells Types of cells

Eukaryote animal cells

- no organelles

- organelles

Eukaryote plant cells

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Cell Size

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Why organelles?   Specialized structures

-  specialized functions   Containers

-  partition cell into compartments -  create different local environments (separate pH’s,

or concentration of materials) -  distinct and incompatible functions

  Membranes as sites for chemical reactions -  unique combinations of lipids and proteins -  embedded enzymes and reaction centers

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Cells gotta work to live!   What jobs do cells have to do?

1.  make proteins   proteins control every cell function

2.  make energy   for daily life   for growth

3.  make more cells   growth   repair   renewal

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Proteins do all the work!

cells

DNA proteins

organism Repeat after me…

Proteins do all the work!

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Cells functions   Building proteins

-  read DNA instructions -  build proteins -  process proteins

  folding  modifying

 removing amino acids  adding other molecules  address and transport proteins

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Building Proteins   Organelles involved

  nucleus   ribosomes   endoplasmic reticulum

(ER)   Golgi apparatus   vesicles

nucleus ribosome ER Golgi apparatus vesicles

The Protein Assembly Line

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nuclear pores

nuclear pore

nuclear envelope nucleolus

  contains most of cell’s DNA   Function

-  protects DNA   Structure

-  nuclear envelope   double membrane  membrane fused in spots to create pores which

allow large macromolecules to pass through

Nucleus

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DNA

Nucleus mRNA

nuclear membrane

small ribosomal

subunit

large ribosomal

subunit

cytoplasm

mRNA

nuclear pore

production of mRNA from DNA in nucleus

mRNA travels from nucleus to ribosome in cytoplasm through nuclear pore

1

2

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Nucleolus

  Function −  ribosome production −  build ribosome subunits from rRNA and proteins

  exit through nuclear pores to cytoplasm and combine to form functional ribosomes

small subunit

large subunit

ribosome

nucleolus

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small subunit

large subunit Ribosomes

  Function -  protein production

  Structure -  rRNA and protein -  2 subunits combine 0.08µm

Ribosomes Rough

ER

Smooth ER

AP Biology membrane proteins

Types of Ribosomes   Free ribosomes

-  suspended in cytosol -  synthesize proteins that function

in cytosol   Bound ribosomes

-  attached to endoplasmic reticulum

-  synthesize proteins for export or for membranes

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Endoplasmic Reticulum (ER)   “little net within the cytoplasm”   Functions

-  processes proteins -  manufactures membranes -  synthesis and hydrolysis of

many compounds   Structure

-  membrane connected to nuclear envelope and extends throughout cell

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Types of ER

rough smooth

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Smooth ER functions   Many metabolic processes…

  synthesis -  synthesize lipids (oils, phospholipids, steroids

and sex hormones)   hydrolysis

-  hydrolyze glycogen into glucose (in liver) -  detoxify drugs and poisons (alcohol and

barbiturates) by adding OH groups, making them more soluble and easier to flush from the body

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Rough ER functions   produce proteins for export out of cell

-  secretory proteins are glycoproteins -  packaged into transport vesicles for export

  produce membrane for the cell -  builds new membrance -  membrane buds off and goes to parts of cell that

needs membrane

Which cells have lot of rough ER?

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Synthesizing proteins

cytoplasm

cisternal space

mRNA

ribosome

membrane of endoplasmic reticulum

polypeptide

signal sequence

ribosome

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Golgi Apparatus

transport vesicles

secretory vesicles

  Structure - consists of flattened sacs (cisternae) with a cis and trans

side

  Function -  finishes, sorts, tags and ships cell products -  ships products in vesicles

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Golgi Apparatus

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Vesicle transport

vesicle budding from rough ER

fusion of vesicle with Golgi apparatus

migrating transport vesicle

protein

ribosome

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proteins

transport vesicle Golgi

apparatus

vesicle

smooth ER

rough ER

nuclear pore nucleus

ribosome

cell membrane protein secreted

cytoplasm

Making proteins

Regents Biology

DNA

RNA

ribosomes

endoplasmic reticulum

vesicle

Golgi apparatus

vesicle

protein on its way!

protein finished protein

Making Proteins

TO:

TO:

TO:

TO:

nucleus

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