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EUKARYOTE CELL ULTRASTRUCTURE
Primary Cell Structure That which can be seen using the light microscope © P Billiet © 2010 Paul Billiet ODWSODWS
Ultrastructure That which can be observed under the electron microscope
EUKARYOTE CELL ULTRASTRUCTURE 20 nm diameterProtein synthesisRibosome 26 to 56 nm thickSupport, Golgi apparatus synthesis Endoplasmic Reticulum (ER) Cisternae: 0.5µm thick, l-3µm diameter Secretion, reprocessing, lysosome synthesis Golgi apparatus 0.5 to 3.0 µm diameterDigestion, recycling & isolation Lysosome 5 to 10 µm diameterPhotosynthetic pathwaysChloroplast 1.0 to 12.5 µmRespiration pathwaysMitochondrion 10 µm diameterCell division, protein synthesis Nucleus DIMENSIONSMAIN FUNCTIONSORGANELLE © 2010 Paul Billiet ODWSODWS
NUCLEUS (latin kernel) TEM Nucleus of a rat hepatocyte Image Credit: www.sinauer.com
NUCLEUS (pl nuclei) Usually spherical occupying up to 75% of the cell volume 10 µm © 2010 Paul Billiet ODWSODWS
NUCLEUS Chemical composition Protein: Up to 90%, HISTONES rich in basic amino acids. Deoxyribonucleic Acid (DNA) about 20% (acidic) Ribonucleic Acid (RNA) 5 to 20% Nuclei usually contain about 10% CHROMATIN = Histone + DNA = NUCLEOPROTEIN. © 2010 Paul Billiet ODWSODWS
NUCLEUS Functions Main site of DNA in eukaryotic cells Preservation, replication and expression of genetic information It makes RNA for protein synthesis It copies DNA for cell division © 2010 Paul Billiet ODWSODWS
MITOCHONDRION (gk mitos = thread khondrion = granule) Image Credit: University of GeorgiaUniversity of Georgia TEM of mitochondrion from mouse kidney cell
MITOCHONDRION (pl. mitochondria) outer membrane inner membrane Mitochondrial envelope Inter membrane space Cristae Inner matrix 1.0 to 12.5 µm © 2010 Paul Billiet ODWSODWS
MITOCHONDRION Pigments Cytochromes Functions The inner membrane contains the enzyme necessary for the synthesis of Adenosine Triphosphate (ATP) The mitochondria are closely associated with the pathways of respiration These metabolic pathways are divided up and supported by the membranes © 2010 Paul Billiet ODWSODWS
CHLOROPLAST (Gk chloros = green plast = form or shape) Image Credit: University of WisconsinUniversity of Wisconsin TEM chloroplast
CHLOROPLAST outer membrane inner membrane Chloroplast envelope Starch grains Grana Frets Thylakoid membrane Stroma 5 to 10 µm © 2010 Paul Billiet ODWSODWS
CHLOROPLAST Pigments Mainly chlorophylls with carotenoids and others Function: Photosynthesis The metabolic pathways are closely associated with the membranes as in the case of the mitochondrion © 2010 Paul Billiet ODWSODWS
Organelles and evolution Both chloroplasts and mitochondria are double membrane bound They involved in energy reactions They contain extranuclear DNA and characteristic small ribosomes of their own This has led biologists to believe that there may be some similarity in their origins in the cells of eukaryotes. The endosymbiotic theory © 2010 Paul Billiet ODWSODWS
LYSOSOME Image Credit: http://www.biokurs.de/http://www.biokurs.de/
LYSOSOME Not discovered by electron microscopy but by centrifugation and enzyme analysis Some scientists suggest that they are not present in plant cells Structure: Simple, spherical, single membrane bound Lysosomes contain a large number of CATABOLIC enzymes. Catabolic enzymes digest materials by hydrolysis © 2010 Paul Billiet ODWSODWS
Enzymes found in lysosomes ENZYMESUBSTRATE Acid phosphatasePhosphate esters Acid ribonucleaseRNA Acid deoxyribonucleaseDNA GlycosidasesPolysaccharides ProteaseProteins and peptides LipaseLipids PhospholipasePhospholipids More than 40 types of enzymes are known to occur in lysosomes. © 2010 Paul Billiet ODWSODWS
LYSOSOME Function Digestion of compounds taken in by the cell by endocytosis Recycling of material within the cell © 2010 Paul Billiet ODWSODWS
GOLGI APPARATUS Image Credit: International Journal of MorphologyInternational Journal of Morphology
GOLGI APPARATUS Golgi vesicles transport the materials from one cisterna to the next Cisternae are flattened sacs Transport vesicles bring material from the endoplasmic reticulum to the entry face Golgi vesicles take transformed materials from the exit face to their destination © 2010 Paul Billiet ODWSODWS
GOLGI APPARATUS Functions Processing and packaging Synthesising lysosomes to contain the potentially dangerous catabolic enzymes Producing secretory vesicles e.g. mucus Making more plasma membrane © 2010 Paul Billiet ODWSODWS
ENDOPLASMIC RETICULUM (ER) Image Credit: www.lifesci.sussex.ac.uk/www.lifesci.sussex.ac.uk/
ENDOPLASMIC RETICULUM (ER) Rough ER Smooth ER Transport vesicles Lumen which can occupy up to 10% of the cell volume Membranes © 2010 Paul Billiet ODWSODWS
ER Functions Not easy to study the ER is that it is difficult to extract intact ER starts the biosynthetic pathways form many protein and lipid molecules in the cell These continue in the Golgi apparatus Rough ER has ribosomes attached to it as opposed to Smooth ER The proteins are made on rough ER will eventually be secreted outside the cell © 2010 Paul Billiet ODWSODWS
RIBOSOME Image Credit: www.palaeos.com/www.palaeos.com/ Image Credit: British Society for Cell BiologyBritish Society for Cell Biology
RIBOSOME NOT membrane bound Found both in pro- and eukarotes The subunits are synthesised separately in the nucleolus of the nucleus of eukaryotes Large ribosome subunit Small ribosome subunit © 2010 Paul Billiet ODWSODWS
RIBOSOME Distribution in the cytoplasm single free-floating attached to rough ER linked together as a POLYRIBOSOME or POLYSOME Function: Protein synthesis Chemical composition Protein + RNA in other words it is a nucleoprotein © 2010 Paul Billiet ODWSODWS
The relationship between organelles Nucleus ER Golgi apparatus Lysosome Ribosomes Endocytosis Exocytosis © 2010 Paul Billiet ODWSODWS
Function of Cell Organelles. Each cell organelle has a different function All organelles within a cell work together to ensure that the cell functions.
Organelle Structure and function
KEY CONCEPT Eukaryotic cells share many similarities.
What is the primary functions of the nucleus?
Recognise cell structures under the electron microscope Outline the function of the different cell organelles Use the New Biology 1 handout for your.
Cell Ultrastructure Plant and animal cells. Objectives describe and interpret drawings and photographs of eukaryotic cells as seen under an electron.
Cell Organelles Prokaryotic cells lack a nucleus and most internal structures of eukaryotic cells. All cells share certain characteristics. –Cells tend.
The following is a glossary of animal cell anatomy terms.
Protein Synthesis Summary. Protein Synthesis 1. The DNA double helix unwinds to expose a sequence of nitrogenous bases. (A,T,C,G) 2. A copy of one of.
Cells Bio 1 Mr. Hellmer.
Cell Types and Cell Structure
Organization of the Cell
amyloplast - an organelle in some plant cells that stores starch. Amyloplasts are found in starchy plants like tubers and fruits. ATP - ATP is short for.
All organisms are composed of cells Cells are the smallest living unit of living things All cells come from cells The Cell Theory Spontaneous generation.
Chapter 4. Most Cells Are Microscopic Effect of Cell Size on Surface Area.
Cell Structure Electron micrograph of a human embryonic stem cell.
Do Now: Look at the cell organelle sheet
KEY CONCEPT Cells are the Basic unit of life.
Organelle Structure and Function. Review Prokaryotes simple celled organisms No nucleus Eukaryotic cells multicellular organisms Nucleus organelles.
Chapter 4 A tour of the cell. Cell Theory u All living matter is composed of one or more cells. u The cell is the structural and functional unit of life.
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