Ch 4 Openstax/6 Campbell: A Tour of the Cell

Cell Types: Prokaryotic Nucleoid: DNA No organelles w/ membranes Ribosomes: protein synthesis, all cells Plasma membrane: semi-permeable, all cells Cytoplasm/cytosol: fluid inside cell, all cells Can also have cell wall/flagella/cilia/etc.

Cell size As cell size increases: Surface area to volume ratio decreases Transport needs increase faster than capability Cell size, therefore, usually remains small

Nucleus Genetic material: Double membrane envelope w/ pores Chromatin: loose DNA/protein Chromosomes: condensed DNA/protein nucleolus: rRNA; ribosome synthesis Double membrane envelope w/ pores Role in Protein synthesis

Ribosomes Protein synthesis Free = cytosol; proteins used in cell Bound = ER; proteins for membranes & export

Endomembrane system, I Endoplasmic reticulum (ER) Continuous w/ nuclear envelope Transport (lumen) Smooth ER no ribosomes, detox makes lipids, metabolize carbs Rough ER w/ ribosomes; secretory protein creation (glycoproteins), membrane production

Nucleus Rough ER Smooth ER cis Golgi Plasma membrane trans Golgi Fig. 6-16-3 Nucleus Rough ER Smooth ER cis Golgi Figure 6.16 Review: relationships among organelles of the endomembrane system Plasma membrane trans Golgi

Endomembrane system, II Golgi apparatus Modify, store, ship ER products Cisternae: flattened membranous sacs trans face (shipping) & cis face (receiving) Transport vesicles

Endomembrane system, III Lysosomes sac of hydrolytic enzymes; digests macromolecules Phagocytosis Autophagy: recycle cell’s organics Tay-Sachs disease: lipid-digestion disorder Animation: Lysosome Formation

Endomembrane system, IV Vacuoles Membrane-bound sacs (larger than vesicles) Food (phagocytosis) Contractile (pump excess water) Central (storage in plants) tonoplast membrane Video: Paramecium Vacuole

Other membranous organelles I Mitochondria quantity linked w/ metabolism; highest in? Aerobic cellular respiration double membrane cristae/matrix intermembrane space contain own DNA

Other membranous organelles II Chloroplast plastid, double membrane thylakoids grana Stroma Has own DNA

Peroxisomes Single membrane Produce H2O2 Metabolism of fatty acids; detox of alcohol (liver) Product = water

Video: Cytoplasmic Streaming The Cytoskeleton Fibrous network in cytoplasm Support, motility, biochemical regulation Video: Cytoplasmic Streaming

Cytoskeletal Elements Centrosome (all) and centrioles (animals) Make fibers for cell reproduction Cilia Many small hair like fiber extensions for movement Flagella Fewer larger fiber extensions for movement

Cell surfaces Cell wall: not in animal cells protection, shape, regulation Cellulose (plants), chitin (fungi), peptidoglycan (bacteria)

ENDOPLASMIC RETICULUM (ER) Nucleolus NUCLEUS Rough ER Smooth ER Fig. 6-9a Nuclear envelope ENDOPLASMIC RETICULUM (ER) Nucleolus NUCLEUS Rough ER Smooth ER Flagellum Chromatin Centrosome Plasma membrane CYTOSKELETON: Microfilaments Intermediate filaments Microtubules Figure 6.9 Animal and plant cells—animal cell Ribosomes Microvilli Golgi apparatus Peroxisome Mitochondrion Lysosome

Rough endoplasmic reticulum Fig. 6-9b Nuclear envelope Rough endoplasmic reticulum NUCLEUS Nucleolus Chromatin Smooth endoplasmic reticulum Ribosomes Central vacuole Golgi apparatus Microfilaments Intermediate filaments CYTO- SKELETON Microtubules Figure 6.9 Animal and plant cells—plant cell Mitochondrion Peroxisome Chloroplast Plasma membrane Cell wall Plasmodesmata Wall of adjacent cell

10 µm Column of tubulin dimers Tubulin dimer   25 nm Table 6-1a

Table 6-1b 10 µm Table 6-1b Actin subunit 7 nm

Fibrous subunit (keratins coiled together) Table 6-1c 5 µm Table 6-1c Keratin proteins Fibrous subunit (keratins coiled together) 8–12 nm

You should now be able to: Distinguish between the following pairs of terms: magnification and resolution; prokaryotic and eukaryotic cell; free and bound ribosomes; smooth and rough ER Describe the structure and function of the components of the endomembrane system Briefly explain the role of mitochondria, chloroplasts, and peroxisomes Describe the functions of the cytoskeleton Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Describe the structure of a plant cell wall Compare the structure and functions of microtubules, microfilaments, and intermediate filaments Explain how the ultrastructure of cilia and flagella relate to their functions Describe the structure of a plant cell wall Describe the structure and roles of the extracellular matrix in animal cells Describe four different intercellular junctions Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings