* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download CYTOLOGY & HISTOLOGY
Survey
Document related concepts
Extracellular matrix wikipedia , lookup
Cell growth wikipedia , lookup
Tissue engineering wikipedia , lookup
Signal transduction wikipedia , lookup
Cell membrane wikipedia , lookup
Cell culture wikipedia , lookup
Cellular differentiation wikipedia , lookup
Cell encapsulation wikipedia , lookup
Cytokinesis wikipedia , lookup
Organ-on-a-chip wikipedia , lookup
List of types of proteins wikipedia , lookup
Transcript
CYTOLOGY & HISTOLOGY Lecture two DR. ASHRAF SAID Review Of the first lecture Concept 1 To study cells, biologists use microscopes and the tools of biochemistry Isolating Organelles by Cell Fractionation Cell fractionation – Takes cells apart and separates the major organelles from one another The centrifuge – Is used to fractionate cells into their component parts Concept 2 Eukaryotic cells have internal membranes that compartmentalize their functions Two types of cells make up every organism – Prokaryotic – Eukaryotic Comparing Prokaryotic and Eukaryotic Cells All cells have several basic features in common – They are bounded by a plasma membrane They contain a semi-fluid substance called the cytosol – They contain chromosomes – They all have ribosomes Eukaryotic cells – Contain a true nucleus, bounded by a membranous nuclear envelope – Are generally quite a bit bigger than prokaryotic cells – The logistics of carrying out cellular metabolism sets limits on the size of cells – Have extensive and elaborately arranged internal membranes, which form organelles Prokaryotic cells – Do not contain a nucleus – Have their DNA located in a region called the nucleoid Start Of this lecture Objectives of lecture two A Panoramic View of the Pro/Eu-karyotic Cells The Nucleus: Genetic Library of the Cell Ribosomes: Protein Factories in the Cell Concept 3 The eukaryotic cell’s genetic instructions are housed in the nucleus and carried out by the ribosomes A animal cell ENDOPLASMIC RETICULUM (ER) Nuclear envelope NUCLEUS Nucleolus Rough ER Smooth ER Chromatin Flagelium Plasma membrane Centrosome CYTOSKELETON Microfilaments Intermediate filaments Ribosomes Microtubules Microvilli Golgi apparatus Peroxisome Figure 1.9 Lysosome Mitochondrion In animal cells but not plant cells: Lysosomes Centrioles Flagella (in some plant sperm) The Nucleus: Genetic Library of the Cell The nucleus – Contains most of the genes in the eukaryotic cell The nuclear envelope Encloses the nucleus, separating its contents from the cytoplasm Figure 1.10 Nucleus 1 µm Nucleolus Chromatin Nucleus Nuclear envelope: Inner membrane Outer membrane Nuclear pore Pore complex Rough ER Surface of nuclear envelope. 1 µm Ribosome 0.25 µm Close-up of nuclear envelope Ribosomes: Protein Factories in the Cell Ribosomes – Are particles made of ribosomal RNA and protein Ribosomes – Carry out protein synthesis Ribosomes Cytosol ER Endoplasmic reticulum (ER) Free ribosomes Bound ribosomes Figure 1.11 Large subunit 0.5 µm TEM showing ER and ribosomes Small subunit Diagram of a ribosome Concept 4 The endomembrane system regulates protein traffic and performs metabolic functions in the cell The endomembrane system – Includes many different structures The Endoplasmic Reticulum: Biosynthetic Factory The endoplasmic reticulum (ER) –Accounts for more than half the total membrane in many eukaryotic cells The ER membrane Is continuous with the nuclear envelope Figure 1.12 Smooth ER Rough ER ER lumen Cisternae Ribosomes Transport vesicle Smooth ER Nuclear envelope Transitional ER Rough ER 200 µm The ER membrane There are two distinct regions of ER –Smooth ER, which lacks ribosomes –Rough ER, which contains ribosomes Functions of ER Smooth The smooth ER – Synthesizes lipids – Metabolizes carbohydrates – Stores calcium – Detoxifies poison Rough The rough ER – Has bound ribosomes – Produces proteins and membranes, which are distributed by transport vesicles