Transcript Chapter 4 (Part A) : Eukaryotic Cells

Chapter 4 (Part A) : Eukaryotic Cells
Eukaryotic cell structures:
•E u k a r y o t e = o r g a n i s m s c o n s i s t i n g o f o n e o r m o r e
complex cells containing organelles
•A n i m a l s , p l a n t s , f u n g i , p r o t i s t s a r e e u k a r y o t i c
Parts -1. Cell walls: animal cells don’t have them; plants, fungi, some protists do
2. Plasma membrane: selectively-permeable barrier to environment;
phospholipids and proteins
3. Nucleus: largest membrane-bound organelle in a cell; contains DNA +
proteins (histones) in the form of chromosomes; covered by a double membrane
with nuclear pores; where the genetic information is stored
4. Endoplasmic reticulum: 2 types – rough (with ribosomes) and smooth
stacks of membranes from nucleus out into cytoplasm “factories” where many
cellular molecules are made
5. Golgi apparatus:“packaging and shipping” areas of the cell; stacks of
membranes with vesicles to the outside of the stacks; molecules are processed,
packaged into vesicles, and moved to correct location in cell
Nucleus  ER  Golgi apparatus
6. Lysosomes: special vesicles that contain digestive enzymes and acid fuse with other
vesicles functions: recycle old molecules and organelles lyse infecting bacteria, etc.;
Mycobacterium tuberculosis prevents fusion of lysosome with vesicle in cell containing the
bacteria; the bacteria then ride along with the immune system cell (macrophage)
bacterium
lysosome
nucleus
Macrophage
Macrophage now presenting bacterial antigens
Ribosomes:
made of RNA and proteins
have no membrane
site of protein synthesis
80S in cells; 70S in mitochondria of cells
Ribosome sculpture at Cold Spring Harbor Laboratory, NY
8. Mitochondria: where aerobic respiration occurs; where much ATP is
made; contains its own DNA and ribosomes (70S like bacteria); it is
believed that mitochondria evolved from bacteria taken in by a bigger cell
9. Chloroplasts:
In plants and some protists
Site of photosynthesis
Evolved from photosynthetic bacteria
10. Cytoplasm: about 75% water, used to absorb heat from many
reactions in a cell; dissolved and suspended molecules in cytoplasm
11. Cytoskeleton: “scaffolding” of cell which holds it into a shape and
attaches this cell to another loss of cytoskeleton components may lead to
cancer– rounding up
Fibroblasts
Microtubule endings labeled
12. Flagella: move in a complex, whip-like motion
13. Cilia: hair-like appendages; move mucus.
Flagella video clip
A SEM of rabbit tracheal airway cilia
http://users.umassmed.edu/michael.sanderson/mjslab/image
Video clip of cilia in respiratory tract beating
http://users.umassmed.edu/michael.sanderson/mjslab/image
The End