1. Notes Ch. 6 part 2

2. Mitochondrion site of cellular respiration
enclosed by 2 membranes: outer is smooth & inner is convoluted (cristae)
between membranes is intermembrane space
interior is called the matrix
contains its own DNA & ribosomes
number in cell is related to cell’s level of metabolic activity

3. Chloroplast site of photosynthesis contains chlorophyll
found in leaf cells & cells of other green organs
enclosed by 2 membranes with a narrow intermembrane space
interior fluid is called the stroma
stroma contains stacks of membranous sacs called thylakoids (a stack of thylakoids is called a granum)
contains its own DNA & ribosomes

4. Peroxisome bound by a single layer of phospholipids
contains enzymes that catalyze oxidation reactions producing hydrogen peroxide (H2O2) as a by-product
additional enzymes break down the H2O2 which is toxic to the cell

5. Cytoskeleton network of fibers extending throughout cytoplasm
provides mechanical support to the cell
maintains the shape of the cell
anchors organelles
involved in cell movement (cilia & flagella)
may also be involved in the regulation of biochemical activities

6. Components of the Cytoskeleton
microtubules
shape & support the cell
serve as tracks for the movement of organelles
separate chromosomes during cell division
“9+2” arrangement and dynein arms cause cilia & flagella to beat
grow out from centrosome (which includes a pair of centrioles in animal cells)
continued

7. microfilaments (actin filaments)
built from molecules of actin
help cell bear tension (pulling forces)
play a role in cell motility
works with myosin to cause muscle cell contraction in animals & cytoplasmic streaming in plant cells
intermediate filaments
help cell bear tension
reinforces shape of cell
helps anchor organelles
make up nuclear lamina (lining on nuclear side of nuclear envelope)

8. Cell Wall protects & maintains shape of plant cell
prevents excessive uptake of water
composed primarily of cellulose in plants & chitin in fungi
perforated by channels called plasmodesmata that connect adjacent cells

9. Extracellular Matrix
consists primarily of glycoproteins (carbohydrate attachments to membrane proteins)
most abundant glycoprotein is collagen

10. Intercellular Junctions
Plant Cells
plasmodesmata = cytoplasmic channels between adjacent plant cells
Animal Cells
tight junctions = bind cells tightly together to prevent fluid from leaking into surrounding tissues
desmosomes = anchoring junctions (fasten cells together)
gap junctions = cytoplasmic channels between adjacent animal cells