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

Transcription

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

2 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?

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4 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.

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

6 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?

7 Scanning electron micrograph of a fibroblast.

8 Immunofluorescence micrographs showing cytoskeletal components, Tubulin.

9 Immunofluorescence micrographs showing cytoskeletal components, Actin.

10 Immunofluorescence micrographs showing cytoskeletal components, Keratin.

11 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.

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

13 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.

14 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?

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17 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

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19 Mammalian organisms are complex associations of cells into tissues and organs. How are they held together?

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21 Antigen Presenting Cell B7 MHC II Antigenic peptide TCR CD4 T Cell CD 4 + CD28 Figure 2

22 CD4 CD3 TCR CD28 PiP 2 InsP 3 + DAG Raf-1 1 Ras MKK Ras/MAPK signaling SOS Lc k Grb-2 Crk1 C3G fyn p116 Vav Lck ZAP-70 Cbl Shc 2 PLC Grb-2 p75 [Ca 2+ ] Calcium signaling calcineurin PI 3 -K p85 3 PKC signaling JNK p110 PKC NF-kβ I-kβ ERK-1.2 NFAT c NFAT AP-1 NF-kβ NFAT Fos/Jun (AP-1) Differential cytokine genes transactivated

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27 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 ionexchange 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 O 2, as shown. In vitro, isolated ATP synthase has only ATP-hydrolyzing (ATPase), not ATP-synthesizing, activity.