Lecture 1, Fall 2014 The structure of the eukaryotic cell, as it relates to cells chemical and biological functions.

There are several important themes that transcends just the chemistry and bring the importance of understanding the cell biological differences between eukaryotes and prokaryotes. These themes are all part of the evolution of eukaryotes. The evolution of internal membrane structures gives rise to the organelles referred to as the cytomembranes, while the other group belongs to the endosymbionts. How they arose and how the endosymbionts evolved has changed greatly since Lyn Margulis origins thesis. What is the advantages of compartmentation? What drove the evolution of compartmentation?

Schematic diagram of an animal cell accompanied by electron micrographs of its organelles. The biochemistry of these organelles are universal. And in many ways similar if not identical to that of prokaryotes.

How do proteins translated on ribosomes from a nuclear mRNA, find the proper cellular site for them to carry out their function?

The model of a cell, but do all cells fit the model? Why do eukaryotes evolve comparmentation of their chemistry into membr bound orangelles? What advantages do these organelles give eukaryotic cells?

Scanning electron micrograph of a fibroblast.

Immunofluorescence micrographs showing cytoskeletal

components, Tubulin.

Immunofluorescence micrographs showing cytoskeletal

components, Actin.

Immunofluorescence micrographs showing cytoskeletal

components, Keratin.

The three types of cytoskeletal filaments: actin filaments, microtubules, and intermediate filaments. Cellular structures can be labeled with an antibody (that recognizes a characteristic protein) covalently attached to a fluorescent compound. The stained structures are visible when the cell is viewed with a fluorescence microscope. (a) Endothelial cells from the bovine pulmonary artery. Bundles of actin filaments called “stress fibers” are stained red; microtubules, radiating from the cell center, are stained green; and chromosomes (in the nucleus) are stained blue.

Simulated cross section of an E. coli cell magnified around one million fold. So, how much free water is there in a cell?

The plasma membranes of cells contain combinations of glycosphingolipids and protein receptors organized in glycolipoprotein microdomains termed lipid rafts. These membr microdomains, compartmentalize cellular processes by serving to organize the assembly of proteins in the membr.

The cell

membrane

; 1. What are the

functions of the

cell membrane?

2. Why is it a

plasma

membrane?

3. What is the origin

of the plasma

membr?

How do you prove that the enzyme you are isolating is present in the organelle you believe it is in?

• EM of fraction

• Purity of fraction

• Marker enzymes

• Monoclonal antibody

Mammalian organisms are complex associations of cells

into tissues and organs. How are they held together?

Antigen Presenting Cell

T Cell CD 4+ CD4

TCR

MHC II

Figure 2

B7

CD28

Antigenic peptide

CD4

Lc

k

Ras Raf-1

MKK

Ras/MAPK

signaling

ERK-1.2

CD3

TCR CD28

fyn

Grb-2 SOS

NFATc

PiP2 InsP3 + DAG

PLC

[Ca2+]

Calcium

signaling

calcineurin

PI3-K p85

p110

PKC

signaling

JNK

PKC

Grb-2

ZAP-70 Lck

p75

3

2 1

I-kβ

NF-kβ

NF-kβ

Differential cytokine genes transactivated

AP-1 NFAT

NFAT Fos/Jun (AP-1)

Shc

Cbl

Vav C3G

p116 Crk1

Separation of functional complexes of the respiratory chain. The outer mitochondrial membrane is first removed by treatment with the detergent digitonin. Fragments of inner membrane are then obtained by osmotic rupture of the mitochondria, and the fragments are gently dissolved in a second detergent. The resulting mixture of inner membrane proteins is resolved by ion-exchange chromatography into different complexes (I through IV) of the respiratory chain, each with its unique protein composition), and the enzyme ATP synthase (sometimes called Complex V). The isolated Complexes I through IV catalyze transfers between donors (NADH and succinate), intermediate carriers (Q and cytochrome c), and O2, as shown. In vitro, isolated ATP synthase has only ATP-hydrolyzing (ATPase), not ATP-synthesizing, activity.