LECTURE 2- TOPIC 1 Cont'd (intro to cell biology)
1.according to cell theory, the cell is the structural unit of life (true)
2.membrane bound organelles increase the SA:V ratio of eukaryotic cells allowing them to achieve larger
size than prokaryotic cells (false)'
3.a typical eukaryotic cell is 0.03mm in diameter (true)
4.the cytosol of eukaryotic cells is more complex than that of prokaryotic cells (false)
5. E. coli is a model protist (false)
6. Arabidopsis thaliana is popular as a model species because its genome is small (for a flowering plant)
Membrane bound organelles
the outer layer of the nuclear envelope is continuous with the endoplasmic reticulum. comes in two type:
Rough Endoplasmic reticulum
-have ribosomes attached to it
-serving as a site for protein synthesis.
Smooth endoplasmic reticulum
-serves as lipid and steroid synthesis,
-Liver cells are often rich in smooth endoplasmic reticulum
(often found in places responsible for lipid synthesis, or breaking down occurs)
Proteins synthesized in rough endoplasmic reticulum are sent to the golgi complex (they move through
vesicles). Important site of protein modification. Can involved breaking a small protein, into smaller parts,
tagging them-->sorting them--> and then sending them to the right location. in addition to vessicles, you
have lysosomes, and peroxisomes, which serve a variety of functions in break down or degradation.
Vacuole; temporary storage within animal cell.
Large central Vacuole; when plant is watered the central vacuole is filled, and it exerts a pressure on the
other parts of the cell, this is called turgor pressure, this is what gives you a firm or crisp plant.
Mitochondria & Chloroplasts
-both bounded by a double membrane (unlike E.R. vesicles…1 membrane)
-mitochondria have inner membrane that is highly folded, houses proteins throughout. ATP is synthesized in
mitochondria. (oxidative metabolism)
-Chloroplasts:within double membrane you have thylakoids, the site of chlorophyll, where light energy is
absorbed; role to convert light energy to chemical energy
-Common feature, they have there own DNA (mDNA) (cpDNA) single circle DNA(very little protein/NAKED),
they have ribosome that are smaller and less complex.
-The cell cannot synthesize mitochondria and chloroplasts. They only come from pre-existing, they
reproduce by binary fission
*(similar to prokaryotes; size, DNA, ribosomes are similar, reproduction is similar, and their reproduction)
Slide 18 - Endosymbiont Theory -Prokaryotic cells arose before eukaryotic cells (3bn vs 2bn y/ago)
-chemical similarities suggest they cam from a common ancestor.
-The main differe