The Cell—Anatomy & Division Exercise 4 The Cell—Anatomy & Division

What is a cell? Structural & functional unit of ALLLLLL living things Different sizes & shapes Different functions Components may vary but have many common features

Plasma membrane (plasmalemma) Cell Compartments Plasma membrane (plasmalemma) barrier in/out of cell Nucleus “control center” of cell DNA Cytoplasm Fluid AND other organelles

Figure 4.1a Anatomy of the composite animal cell. Nucleus Cytoplasm Plasma membrane 7

Figure 4.1b Anatomy of the composite animal cell. Endoplasmic reticulum Nuclear envelope Nucleus Mitochondria Chromatin Nucleolus 8

Cytoplasmic Organelles Chromatin (in nucleus) DNA + proteins—threadlike form Chromosomes (in nucleus) Before mitosis, chromatin becomes tightly coiled, rod-shaped Nucleolus protein & RNA in nucleus

Figure 4.1b Anatomy of the composite animal cell. Endoplasmic reticulum Nuclear envelope Nucleus Mitochondria Chromatin Nucleolus 10

CHROMATIN NUCLEOLUS Lab Fig. 4-3

Lecture Fig. 3-14

Cytoplasmic Organelles Ribosome Made of RNA Protein synthesis Cytoskeleton (“support beams”) Protein fibers Centrioles: paired cylinders near nucleus Microtubules: thin hollow tubes (transport things in the cell, rigidity) Mitotic spindle forms between centrioles during mitosis

CENTRIOLES RIBOSOMES MICROTUBULES Lab Fig. 4-3

Cytoplasmic Organelles Cytoskeleton (“support beams”) Microfilaments: tiny; cell shape Intermediate filaments: medium, cell-stabilizers

INTERMEDIATE FILAMENTS MICROFILAMENTS INTERMEDIATE FILAMENTS Lab Fig. 4-3

Cytoplasmic Organelles with Membranes Nuclear membrane (envelope) 2-layered Porous: holes for in/out Mitochondria 2-layered membrane with inner folds Powerhouse of cell Food energy ATP energy

NUCLEAR MEMBRANE MITOCHONDRIA Lab Fig. 4-3

Cytoplasmic Organelles with Membranes ER: Canal network continuous with nuclear membrane Smooth endoplasmic reticulum Synthesizes lipids Rough endoplasmic reticulum Ribosomes attached to surface Protein synthesis and transport SMOOTH ER ROUGH ER Lab Fig. 4-3

Cytoplasmic Organelles with Membranes Golgi apparatus Cluster of flattened sacs near rough ER Secretory vesicles Secrete contents out of cell Or Lysosome: digestive enzymes (digest foreign material, old cell parts) Peroxisome: oxidase enzymes (use oxygen to detoxify—free radicals, kidney, liver)

GOLGI APPARATUS SECRETORY VESICLES Lab Fig. 4-3

Figure 4.3 Structure of the generalized cell. Nucleus Chromatin Nuclear envelope Nucleolus Nuclear pore Plasma membrane Smooth endoplasmic reticulum Cytosol Mitochondrion Lysosome Centrioles Rough endoplasmic reticulum Centrosome matrix Ribosomes Golgi apparatus Microvilli Secretion being released from cell by exocytosis Microfilament Microtubule Intermediate filaments Cytoskeletal elements Peroxisome 22

Table 4.1 Summary of Structure and Function of Cytoplasmic Organelles

Cell Membrane Phospholipid bilayer Phospholipids Cholesterol Proteins Hydrophobic tails Hydrophilic heads Cholesterol Lipid, helps stabilize cell membrane Proteins Move around, aid in transport “fluid mosaic model”

FLUID-MOSAIC MODEL PHOSPHOLIPID BILAYER CHOLESTEROL PROTEINS HYDROPHOBIC TAILS HYDROPHILIC HEADS PROTEINS

Figure 4.2 Structural details of the plasma membrane. Extracellular fluid (watery environment outside cell) Polar head of phospholipid molecule Cholesterol Glycolipid Glycoprotein Nonpolar tail of phospholipid molecule Glycocalyx (carbohydrates) Lipid bilayer containing proteins Outward-facing layer of phospholipids Inward-facing layer of phospholipids Cytoplasm (watery environment inside cell) Integral proteins Filament of cytoskeleton Peripheral proteins 26

Cell Division: MITOSIS Interphase Prophase Metaphase Anaphase Telophase Cytokinesis

Microscope slides also

Interphase Early Prophase Late Prophase Figure 4.4 The interphase cell and the events of cell division. (1 of 2) Interphase Early Prophase Late Prophase Polar microtubule Centrosomes (each has 2 centrioles) Plasma membrane Early mitotic spindle Spindle pole Fragments of nuclear envelope Aster Nucleolus Chromatin Chromosome consisting of two sister chromatids Centromere Nuclear envelope Kinetochore Kinetochore microtubule 29

Interphase Early Prophase Late Prophase Figure 4.4 The interphase cell and the events of cell division. (1 of 2) Interphase Early Prophase Late Prophase Polar microtubule Centrosomes (each has 2 centrioles) Plasma membrane Early mitotic spindle Spindle pole Fragments of nuclear envelope Aster Nucleolus Chromatin Chromosome consisting of two sister chromatids Centromere Nuclear envelope Kinetochore Kinetochore microtubule 30

Metaphase Anaphase Telophase Cytokinesis Figure 4.4 The interphase cell and the events of cell division. (2 of 2) Metaphase Anaphase Telophase Cytokinesis Nucleolus forming Contractile ring at cleavage furrow Nuclear envelope forming Spindle Metaphase plate Daughter chromosomes 31

Cell Division: MITOSIS Interphase Normal cell activities PRIOR to division Then it gets the signal to divide Copy DNA Copy organelles Copy centrioles Lab Fig. 4-4

Cell Division: MITOSIS Prophase Chromosomes w/sister chromatids Centrioles separated, spindle Nuclear membrane breaks down Lab Fig. 4-4

Cell Division: MITOSIS Metaphase Chromatids @ middle Lab Fig. 4-4

Cell Division: MITOSIS Anaphase Chromatids split, to opposite ends Lab Fig. 4-4

Cell Division: MITOSIS Telophase Chromatin again Spindle breaks down Nuclear membrane Lab Fig. 4-4

Cell Division: MITOSIS Cytokinesis Division of cytoplasm 2 new cells each genetically IDENTICAL

Review Figure 4.1 38

Review Figure 4.2 39