Chapter Seven A View of the Cell

Cellular Organization

• Cell • Tissue – group of cells functioning

together. • Organ – group of tissues

functioning together. • Organ System – group of organs

functioning together. • Organism – group of organ

systems functioning together.

The History of the Cell

• The Cell – The basic unit of an _______ – Discovery made possible by the invention of the _______

Microscopes and Cells

• 1600’s. – _____________________________ first described living cells as seen through a simple microscope.

Microscopes and Cells

– ____________used the first compound microscope to view thinly sliced cork cells.

• _____________ use a series of lenses to magnify in steps. • Hooke was the first to use the term “_______”.

Microscopes and Cells • 1830’s.

– _______________identified the first plant cells and concluded that all plants

made of cells. - __________________ made the same conclusion about animal cells.

Cell Theory:

• All organisms are made up______________________.

• The cell is the ____________________of all organisms.

• All cells come from ______________________.

_____ Basic Cell Types

1) _________ – Lacks internal compartments.

– No true _________. – Most are single-celled (unicellular) organisms.

– Examples: ________

Two Basic Cell Types 2) Eukaryote

– Has several internal structures (organelles).

– True nucleus. – Either unicellular or multicellular.

unicellular example: yeast multicellular examples: plants and animals

Cell size comparison

Bacterial cell

Animal cell

  micron = micrometer = 1/1,000,000 meter   diameter of human hair = ~20 microns

most bacteria   1-10 microns

eukaryotic cells   10-100 microns

The Parts of The Eukaryotic Cell 1) Boundaries

A) ____________________ -- Serves as a boundary between the cell and its external environment.

-- Allows materials to ________________________________________________

1) Boundaries

B) __________________ -- Surrounds the ____________________ of the cells of plants, bacteria, and fungi. -- Plant cell walls contain _________ while fungi cell walls contain _______.

The Parts of The Eukaryotic Cell: 2) Controls

A) __________ • Regulates cell function. • Surrounded by a double-layered membrane (_______________________) with large pores that allow materials to pass in and out of the nucleus.

• Contains _______ – long tangles of ______.

2) Controls

B) _____________ • Found in the __________ and responsible for ribosome production. Ribosomes are the sites of _________________.

The Parts of The Eukaryotic Cell: 3) Assembly

– ___________ • The ____________ material that surrounds the organelles.

The Parts of The Eukaryotic Cell: 4) Transport

A) ________________________ • Folded membrane that acts as the cell’s delivery system.

• __________________ contains enzymes for lipid synthesis.

• __________________ is studded with ribosomes for ________________.

4) Transport B) ___________________ (or Golgi body)

• A series of flattened sacs where newly made lipids and proteins from the E.R. are repackaged and shipped to the plasma membrane.

The Parts of The Eukaryotic Cell: 5) Storage

A)  ___________

• A sac of fluid surrounded by a membrane used to _______ food, fluid, or waste products.

5) Storage B) ___________________

• Contain ______________. • Can fuse with vacuoles to____________, or can digest worn cell parts.

• Also known as “suicide sacs” because they can also destroy the whole cell.

The Parts of The Eukaryotic Cell: 6) Energy Transformers

A)_______________ Produce the ________

for the cell. Also known as the

“powerhouse of the cell”.

Has a highly folded inner membrane

(cristae).

6) Energy Transformers B) ______________

-- Found in _________ cells and some protists. -- Transforms light energy into chemical energy which is stored in food molecules. -- Contain _______________ – a green pigment that traps light energy and gives plants their green color.

The Parts of The Eukaryotic Cell: 7) Support

– _________________ • A network of thin, fibrous materials that act as a scaffold and support the organelles.

• _____________ – hollow filaments of protein.

• _____________ – solid filaments of protein.

The Parts of The Eukaryotic Cell: 8) Locomotion

1) __________ • Short, numerous, ______________________________________________from the plasma membrane.

• Move with a coordinated beating action.

8) Locomotion

B) ____________

• Longer, less numerous projections from the plasma membrane.

• Move with a ___________ action.

The Parts of The Eukaryotic Cell: 9) Cell Division

___________ – made of protein. – play a role in the splitting of

the cell into two cells. – found in animal and fungi cells.

Composite Animal Cell

bacteria cells

Types of cells

animal cells plant cells

Prokaryote - no organelles

Eukaryotes - organelles

Movement Across the Membrane

•  Establishes Homeostasis •  Occurs through channel proteins •  Can be active or passive

–  ____________transport does not require energy –  ____________transport does require energy

Passive Transport - Diffusion •  Particles in a solution move constantly •  Particles tend to move from an area of

________concentration to _______ concentration

•  When concentration is equal everywhere, it has reached equilibrium

•  Substances diffuse across membranes without requiring the cell to use energy (___________________)

Diffusion

Diffusion- movement from _____ concentration _____concentration

Passive Transport-Osmosis

•  If a substance can diffuse across a membrane, the membrane is said to be _____________ to it and ________________ if it can't diffuse across it

•  Water diffuses easily

•  ______________ is the diffusion of water across a _______________________________ membrane from an area of high concentration to low concentration

Osmosis •  The direction of osmosis is determined by

comparing total solute concentrations –  ________________-more solute, less water –  ISOTONIC- equal solute, equal water –  ________________- less solute, more water

hypotonic hypertonic

freshwater balanced saltwater

Managing water balance •  Cell survival depends on balancing water

uptake & loss

Diffusion through phospholipid bilayer •  What molecules can get through directly?

–  _____ & other lipids

inside cell

outside cell

lipid salt

aa H2O sugar

NH3

 What molecules can NOT get through directly?   _______

molecules   H2O

  ions (charged)   salts, ammonia

  large molecules   starches, proteins Semipermeable

Passive Transport-Facilitated Diffusion Cell membranes have ___________that act

like carriers, making it easier for certain molecules to cross. They "facilitate" the diffusion of molecules.

There are hundreds of different channels that only allow certain molecules to come through.

It will only occur if there is a higher concentration on one side of the membrane. It doesn't require energy. It's passive transport.

Channel protein

Active Transport

•  Cells may need to move molecules ___________ concentration gradient –  protein “pump” –  “costs” energy = __________

How about large molecules? •  Moving large molecules into & out of cell

–  through vesicles & vacuoles –  ____________

•  phagocytosis = “cellular eating” •  pinocytosis = “_____________”

–  exocytosis

exocytosis

Endocytosis

phagocytosis

pinocytosis

receptor-mediated endocytosis

fuse with lysosome for digestion

non-specific process

triggered by molecular signal

Getting through cell membrane •  Passive Transport

–  _______________ •  diffusion of nonpolar, hydrophobic molecules

–  lipids –  _________________ concentration gradient

–  Facilitated transport •  diffusion of polar, hydrophilic molecules •  through a _________________

–  HIGH → LOW concentration gradient

•  Active transport –  diffusion ___________________________________

•  LOW → HIGH –  uses a ________________ –  requires _______________

ATP

Cell Membrane •  Cell membrane establishes

___________________for the cell by controlling what passes in and out of the cell.

•  HOW? 1.  ______________________________creates a

barrier 2.  ___________________ that allow polar

substances through 3.  Glyco-proteins are name tags

Phospholipid Bilayer

Glycoprotein

Integral Proteins

Peripheral Proteins