Eukaryotic Cell

Eukaryotic Cell

1. What are the differences between prokaryotes an eukaryotes

   • Cell division in prokaryotic cell involves binary fission and eukaryotic cell involves mitosis
     • The chromosome in prokaryotic cell is usually single circular chromosomes that lack histones. But for eukaryotic cells, it has multiple linear chromosomes with histones
       • Prokaryotic cells have no nuclear membrane/nucleoli but eukaryotic cells have true nucleus consisting of nuclear membrane and nucleoli
         • Prokaryotic cells lack of membrane bound organelles but eukaryotic cells have organelles such as lysosomes, golgi complex endoplasmic reticulum, mitochondria and chloroplast
           • Plasma membrane of prokaryotic cell have no carbohydrates and lacks sterols but compared to eukaryotic cells have sterols and carbohydrates
             • Size of the prokaryotic cell is 0.2- 2.0 micrometer in diameter but eukaryotic has 10-100 micrometer in diameter

2. External Structures

   • Flagella and cilia
     • Flagella(few and long), Cilia (short and numerous)
     • Anchored to plasma membrane by a basal body
     • Consist of 9 pairs of microtubules arranged in a ring (9+2 array). Microtubules is protein tubulin
     • Movement is wavelike for eukaryotic (flagellum) and rotation (prokaryotes)
   • Cell wall and glycocalyx
     • Eukaryotes may have or may not have cell wall. If they have, more simpler than prokaryotes
     • Major components of algae/plants is cellulose
     • Fungi, chitin
     • Yeasts have glucan and mannan
     • Protozoa have pellicle
     • If no cell wall, plasma membrane as outer covering and NO PEPTIDOGLYCAN

3. Internal Structures

   • Plasma membrane
     • NO GROUP TRANSLOCATION
     • Contain sterols
     • Types of endocytosis
       • Phagocytosis which is extension of pseudopods to engulf and bring particles into cells
       • Pinacytosis is process of plasma membrane folds inwards
       • Exocytosis is mechansims by which cells release secretions
   • Cytoplasm
     • Contain microfilaments, intermediate filaments and microtubules that form the cytoskeleton
     • Cytoskeleton provide support and shape, assisting in transporting substances through cytoplasmic streaming
   • Ribosomes
     • Attached to outer surface of RER. It is site of protein synthesis 80S ribosomes (60S subunit and 40S subunit)
   • Organelles
     • Nucleus
       • Contains all the cells hereditary information. Surrounded by double membrane nuclear envelope. DNA combine with histones
       • When reproducing DNA and histone shorter thicker rodlike called chromosomes. When not reproducing, DNA and histone in threadlike called chromatin
     • Endoplasmic reticulum
       • Rough ER- site for synthesize secretory proteins. Smooth ER- synthesizes phospholipids
     • Golgi complex
       • - Receiving side - Modifies protein
     • Lysosomes
       • -Destruction of foreign material -Digestion of food particles
     • Vacoules
       • Storage of metabolic wastes and provide rigidity
     • Mitochondria
       • ATP production. Consist of double membrane and outer membrane. It is smooth and arranged in series of folds calles cristae
     • Chloroplast
       • Found in green plants and algae. Contains chlorophyll for photosynthesi
     • Peroxisomes
       • Decompose hydrogen peroxide and oxidize toxic substances
     • Centrosomes
       • Center for mitosis process. Consist of pericentriolar material and centriols (9+0 microtubules triplets arrangement

4. Mitosis is process of replacing new cells

   • Produces two daughter cells that are identical to the parent cell
   • Phases in mitosis is interphase, prophase, metaphase, anaphase, telophase G1 interphase and G2 interphase.

5. Meiosis is process of sexual reproduction

   • Meiosis produces daughter cells that have half the number of chromosomes as the parent cell. 2N----->N
     • Involves two divisions which is meiosis 1 and 2, producing total of four daughter cells