Bellwork – Introduction to book and course.

Grab a book and read pg. vi

The Parts of the Cell

http://youtube.com/v/u54bRpbSOgs

The Parts of the Cell

The Nucleus 

The Nucleus--nuclear envelope with nuclear pores and nucleoplasm -- chromatin  -->  chromosomes--DNA remains in the nucleus, it sends instructions to the cytoplasm via messenger RNA--RNA directs the synthesis of proteins on ribosomes in the cytoplasm--Nucleolus assembles ribosomes 

Endoplasmic Reticulum -- Transport System endoplasm means "within cytoplasm", reticulum means "little net"

--divides cell into compartments--channels molecules through the cell's interior, like a little highway

Rough ER--has ribosomes which give it its "rough" appearance--functions in protein synthesis--ER transports newly assembled proteins to the Golgi Apparatus

Smooth ER--mostly contains enzymes that unction in lipid synthesis (such as hormones like estrogen and testosterone)

Figure 4.10a

Golgi Apparatus -- Delivery System     

--flattened stacks of membranes--functions in collection, packaging and distribution of molecules made in the cell and used elsewhere-- front end (cis) faces the ER, and the back end (trans) faces the cell membrane

* folded stacks are called cisternae

unprocessed proteins enter the Golgi apparatus from ERproteins are packaged and exported near membrane

Jobs of the Golgi Apparatus              (aka Golgi Complex)

1. separates proteins according to their destinations2. modifies proteins (adds sugar and makes glycoproteins)3. packages materials into vesicles which are exported outside the cell  -  secretion

Lysosomes - Intracellular Digestion Centers

--vesicles that are used to digest--contain high levels of degrading enzymes          (to "lyse" means to dissolve)--recycle old cell parts--"suicide sac" -  apoptosis--digest other particles taken in by phagocytosis--this "food" is stored in food vacuoles, the lysosomes fuse with the vacuoles and release digestive enzymes--found in animal cells

 TAY-SACHS disease – missing an enzyme of the lysosomes that breaks down a fatty substance.  Over time this fat builds up in the brain and nervous tissue, smothering the cells.  Results in degeneration and death.

Ribosomes - Sites of Protein Synthesis

--each is composed of two subunits, one large and one small--mRNA is "read" by the ribosomes and amino acids are assembled into proteins--ribosomes are manufactured by the nucleolus inside the nucleus--polyribosomes – strings of ribosomes in the cytoplasm that work to make a protein

Other Organelles

-- Peroxisomes – result in hydrogen peroxide, broken down by catalase-- Vacuole  --  mainly storage or specific functions (contractile vacuole)

-- Plant cells have a CENTRAL VACUOLE  - used for storage and help to maintain hydrostatic pressure

Hey....remember enzymes?

The Peroxisome

Found in virtually all plant and animal cells, this organelle plays a critical role in normal cell functioning. In human cells, peroxisomes house some sixty enzymes, involved in such metabolic processes as bile acid, cholesterol, and plasmalogen biosynthesis, as well as ß-oxidation 

As a by-product of its normal function, and the reason the organelle is so named, the peroxisome produces hydrogen peroxide. To neutralize this potentially toxic compound, a normally functioning peroxisome imports the hydrogen peroxide-metabolizing enzyme catalase, from the cytosol of the cell. Catalase converts hydrogen peroxide to water and oxygen

Figure 4.12

ENERGY RELATED ORGANELLES

Mitochondria - The Cell's Chemical Furnaces

--contains its own DNA, support for Endosymbiosis Theory--singular is "mitochondrion"--2 membranes, one smooth outer membrane, and an inner membrane folded into layers called cristae--Cristae has two compartments: the matrix and the intermembrane space

--mitochondria divide before cell division, they are not synthesized like other cell parts--function to store energy for cell use. Energy is stored in the form of ATP - adenosine triphosphate

Figure 4.17

Chloroplasts - Where Photosynthesis Takes Place --only found in plant cells--has its own DNA, like mitochondrion

--functions to convert light energy to carbohydrates--carbohydrates then broken down in mitochondria to produce ATP

--consists of grana, closed compartments that are stacked

--thylakoids are the individual disk shaped compartments that make up the grana (stack of thylakoids)--stroma is the fluid surrounded the thylakoids

*Chloroplasts are a type of plastid

Chromoplasts – red, yellow and orange pigmentLeucoplasts – colorless (potatoes)

Cytoskeleton - Support System

Microfilaments (now called actin filaments) – occur in bundles, form tracks within the cell for the movement of organelles,  used to form pseudopods (ameba)

Intermediate filaments  - support membrane, cell to cell junctions

Microtubules -  (little pipe) – regulated by the MTOC (microtubule organizing center), radiate from the centrosome   -  form the spindle during cell division

Centrioles – used during cell division to move and separate chromosomes, only found in animal cell

Pseudopod – extensions of the cell that allow for movement (ameba), depend on actin filaments

Cilia (hair) & Flagella (whip)

--function in movement-- 9+ 2 Arrangement of microtubules

Post - IT  Cell

Write down the names and descriptions of each cell part on a post it and arrange the parts on your table (work with the person sitting next to you).    Your teacher will assign you one of the following cell types

1.  Bacteria Cell (Prokaryote)2.  Plant Cell3.  Animal Cell

*You will have 15 minutes to construct your cell.  GO!*

Random Cell Images

Figure 4.6b

Figure 4.7a

Figure 4.7b

As seen through a Transmission Electron Microscope

Figure 4.12b

TAY SACHS

DISEASE

Figure 4.13

Figure 4.16

Figure 4.17a

Figure 4.18

Figure 4.19b

a.  ________________

b.  ________________

c.  _________________

d.  _________________

e.  _________________

f.  __________________

f.

What is this structure? 

Figure 4.7b

Figure 4.10a

What is this structure?

What is this structure?

Figure 4.11

Describe the processes occurring in this image.

Figure 4.13

Figure 4.16b

What is this structure?

What is this structure?

What is its function?  

Figure 4.19aWhat is this structure?

Find the:

a.  Nucleolus

b.  Centriole

c.  Vesicle

d.  Smooth ER

e.  Lysosome

Watch the video.  Can you name the cell parts and processes shown?