Principles of Cellular Biology
آشنایی با مبانی اولیه سلول Biologists are interested in objects ranging in size from small molecules to the tallest trees:
Cell Basic building blocks of life Understanding of cell morphology is critical to the study of biotechnology Smallest living unit of an organism Grow, reproduce, use energy, adapt, respond to their environment
Morphological varieties of cells Amoeba Proteus Plant Stem Bacteria Red Blood Cell Nerve Cell
All cells are Prokaryotic or Eukaryotic
Comparing Prokaryotic and Eukaryotic Cells Are mostly bacteria Prokaryotes Genes usually do not have introns Between 500 and 4000 genes Unicellular Have cell membrane Have DNA Have cytoplasm Hereditary info stored in DNA, transcribed into RNA and then translate into protein Eukaryotes Include all plant and animal cells Have organelles and a nucleus Have membranes surrounding organelles Large genome size Between 6,000 and 30,000 genes Genes have introns Unicellular or multicellular
Prokaryotes and Eukaryotes classification Prokaryotes Bacteria Archaea Eukaryotes Unicellular Protists Fungi Multicellular Animal Plant Ostreococcus is the smallest known free living eukaryote with an average size of 0.8 µm Viruses : Must infect a host cell to grow and reproduce
Prokaryotic cells Simplest organisms - Cytoplasm is surrounded by plasma membrane and encased in a rigid cell wall composed of peptidoglycan. Some use flagellum for locomotion - Threadlike structures protruding from cell surface
Bacterial cell morphology
Examples:
Classification of bacteria Bacteria can be classified on the basis of cell structure, cellular metabolism or on differences in cell components such as DNA, fatty acids, pigments, etc. Gram staining Aerobic/Anaerobic Gram positive Gram negative possess a thick cell wall containing many layers of peptidoglycan and teichoic acid have a relatively thin cell wall consisting of a few layers of peptidoglycan surrounded by a second lipid membrane containing lipopolysaccharides and lipoproteins. Bacterial nutrition Autotrophic Heterotrophic 16S ribosomal RNA
Eukaryote cells Characterized by compartmentalization by an endomembrane system, and the presence of membrane-bound organelles. Central vacuole Vesicles (smaller) Chromosomes - DNA and protein Cytoskeleton (internal protein scaffolding) Cell walls plants and fungi
Animal Cell
Plant Cell
Cell Organelles Organelle= little organ Found only inside eukaryotic cells All the stuff in between the organelles is cytosol Everything in a cell except the nucleus is cytoplasm
What are cell organelles & their functions? Types of Organelles Nonmembranous organelles: no membrane direct contact with cytosol Cytoskeleton Microvilli Centrioles Cilia Robosomes Membranous organelles: covered with plasma membrane isolated from cytosol Nucleus Endoplasmic reticulum (ER) Golgi apparatus Lysosomes Mitochondria
Nucleus
Nucleus
Chromosomes DNA of eukaryotes is divided into linear chromosomes. exist as strands of chromatin, except during cell division associated with packaging histones, packaging proteins nucleosomes
Chromosomes to DNA
Organization of DNA Nucleosomes: -DNA coiled around histones Chromatin: -loosely coiled DNA (cells not dividing) Chromosomes: -tightly coiled DNA (cells dividing)
Mitochondria A. "Powerhouse of the cell" - cellular metabolism B. Structure- outer and inner membranes, cristae C. Have their own DNA
Endoplasmic reticulum Compartmentalizes cell, channeling passage of molecules through cell s interior. Rough ER - studded with ribosomes, synthesize protein Smooth ER - few ribosomes, synthesize lipids and steroids, metabolize carbohydrates and steroids, and regulate calcium concentration, and attachment of receptors on cell membrane proteins.
Ribosomes Ribosomes are RNA-protein complexes composed of two subunits that join and attach to messenger RNA. site of protein synthesis assembled in nucleoli
Chloroplast (in plant cells)
Cytoplasm Microtubules Intermediate filaments Actin
Summary
Extracellular Matrix (ECM) Extracellular components and connections between cells help coordinate cellular activities. Most cells synthesize and secrete materials that are external to the plasma membrane. Although these materials and the structures they form are outside the cell, their study is central to cell biology because they are involved in a great many cellular functions. The Extracellular Matrix (ECM) of Animal Cells
The six life processes require a living thing to: Metabolize. Breakdown nutrients for energy or extract energy from the environment. Be responsive. React to internal and external environmental changes. Move. Whether it is the entire organism relocating within its environment, cells within that organism or the organelles inside those cells. Grow. Increase the size or number of cells. Differentiate. The process where cells that are unspecialized become specialized. (An example would be a single fertilized human egg, developing into an individual). Prokaryotic cells do not differentiate Reproduce. Form new cells to create a new individual.
Cellular metabolism Metabolism is the set of chemical reactions that happen in living organism to maintain life. Catabolism: breaks down organic matter, for example to harvest energy in cellular respiration Anabolism: uses energy to construct components of cells such as proteins and nucleic acids The chemical reactions of metabolism are organized into metabolic pathways, in which one chemical is transformed through a series of steps into another chemical, by a sequence of enzymes.
Energy from organic compounds Proteins Polysaccharides Fats Amino acids Monosaccharides Fatty acids AcetylCoA Citric acid cycle NAD+ NADH ADP Oxidative phosphorylation ATP
Cellular respiration is a series of the metabolic reactions occurs in cells in order to convert nutrients into a small energy molecule called adenosine triphosphate (ATP). Anaerobic vs. Aerobic respiration Glycolysis
Aerobic respiration:
Cell division (cell growth) Growth of cell populations, where one cell (the "mother cell") grows and divides to produce two daughter cells". Prokaryotes Eukaryotes 3 types of cell division
Mitosis
Mitosis A chromosome attached to spindle fibers
Meiosis
Growth curve
Factors affecting cell growth Nutrient PH Temperature Dissolved oxygen Bacteria Thermophils Mesophils Psychrophils Aerobics Anaerobics Osmotic pressure and etc.
Cell growth requirements in nutrients Carbon, hydrogen, oxygen, nitrogen, sulfur, phosphorus, potassium Gel Liquid Growth medium: Prokaryotes (bacteria) or A liquid or gel designed to support the growth of microorganisms. Eukaryotes (animal and plant)