Unit 1

• A SEM microscope gives a 3D image while a TEM one gives a 2D image
• Cell is defined by three key attributes: A small membrane enclosed units that are filled with a concentrated aqueous solution of chemicals and endowed with the extraordinary ability to create copies of themselves by growing and then dividing into two.
• The plasma membrane is semipermeable, It surrounds a cytoplasm, it is able to replicate through mitosis (into 2) or meiosis (into 4)
• Cells can replicate, have a membrane and an aqueous solution inside and can be a part of a unicellular or multicellular organism.
• Robert Hooke: Discovered the cell and the corkscrew structure of the cell. He used a microscope to prove living things are elementary structures made up of cells. His findings were published in Micrographia
• Who proposed the cork screw model of the cell?

  Robert Hooke
• Anton Van Leeuwenhoek was in the textile business and developed a microscope that allowed him to observe some cells such as protozoa (bacteria) and red blood cells
• Who was the first to observe red blood cells and protozoa?

  Anton
• The study of cell biology became field of study with the publications of Matthias Schleiden (botanist) and Theodor Schwann (zoologist). Both studied the structures of plant and animal tissue under a light microscope and came to the conclusion that showed cells were the universal building blocks of all living tissue
• Who encouraged the study of cell biology by studying the tissues of animals and plants?

  Schleiden and Schwann
• Rudolf Virchow: He described the concept of cellular theory, stating each animal is the sum of vital units which contain characteristics of life. He stated that all cells come from other cells. We now know this as mitosis. He also stated diseases appeared on a cellular level as opposed to on an organ/tissue level. Published findings in "Cellular Pathology"
• Who proposed the cellular theory of mitosis and disease being cellular?

  Rudolf Virchow
• Brown: Through studying orchids he found the nucleus structure in eukaryotes
• Who found the nucleus?

  Brown
• Cajal: Spanish, developed silver nitrate staining which stained nerve cells, more specifically neurons. This earned him a nobel prize
• Who developed silver nitrate staining?

  Cajal
• Golgi: Used silver nitrate developed by Cajal to identify Golgi apparatus
• Robertson: described the bilayer structure of plasma membrane using the electron microscope
• Who described the bilayer structure of the membrane?

  Robertson
• Kendrew: First to describe detailed protein structure myoglobin, using x-ray crystallography
• Who was the first to describe protein structure / myoglobin?

  Kendrew
• Singer and Nicolson: developed the fluid mosaic model of the plasma membrane. Using Robertson's discovery of the membrane bilayer, they were able to propose that movements occur within these bilayers. The position of proteins and lipids on the membrane would change suggesting this model
• Who proposed the fluid mosaic model of plasma membrane?

  Sing and Nicolson
• Cellular theory: Made up of three criteria. 1 All living organisms are composed of one or more cells (Schleiden and Schwann) 2 the cell is the basic unit of structure and organization in organisms (Schleiden and Schwann) 3 Cells arise from pre-existing cells (Rudolf Virchow). These are considered postulates
• There are 8 properties of living cells: Organization, Energy, Biomolecules, Cell size & number, Cellular communication, Receptors, Cell adaptation and Self regulation
• Property of Living Organism: Organization, meaning cells are made up of atoms, molecules, polymers, biomolecules. Cells then make up tissue. Energy, cells can produce ATP through glycolysis in the cytoplasm, and the krebs cycle and ETP in the mitochondria. Can also carry out metabolic processes throughout the cell. Biomolecules, contain carbohydrates, lipids, proteins, amino acids and nucleic acids. Cell size & number, these are energy and biomolecule mediated. The more of both that it has the bigger cell size and count will be, eukaryotes are also generally larger than prokaryotes.
• Properties of Living Organism: Cellular communication, the transfer of signals between cells such as the autocrine, paracrine and endocrine systems which need signal receptors. Receptors, cells have surface receptors for recognizing signals such as hormones (Insulin, adrenaline and glucagon).
• Properties of Living Organisms: Cell adaptation, depending on compounds within the cell, different processes take place such as krebs cycle or lactic fermentation when O2 levels fluctuate. Self regulation, there are mechanisms in place that increase or decrease the processes occurring in the cell. An example are the positive and negative effectors of allosteric enzymes which cause slowing or speeding up of reactions
• Lynn Margulis: biologist who proposed the case of endosymbiosis
• Who proposed endosymbiosis?

  Lynn Margulis
• Endosymbiosis: When an organism can live inside of a cell within an organism (host cell) for a mutual benefit. In this case this is an aerobic bacterium (prokaryote) and a photosynthetic prokaryote in an anaerobic pre eukaryote. This leads to a eukaryote with mitochondria and chloroplasts, giving rise to a eukaryotic cell capable of photosynthesis
• The first cell to appear was the?

  prokaryotic
• Prokaryotes do not have their DNA enclosed in a membrane
• The eukaryote appeared after the prokaryote as a result of evolutionary transition. Evolution gave rise to a more complex structure with internal membranous compartments and a cytoskeleton. Later, complete genomes incorporated themselves into the pre eukaryotes giving rise to mitochondria, chloroplast, sexual reproduction, and multicellular organisms
• The combination of a pre eukaryotic cell, aerobic prokaryote and photosynthetic prokaryote gives rise to a?

  Eukaryotic cell capable of photosynthesis
• Proof for endosymbiosis: 1. Similar DNA of entering prokaryotes and the resulting mitochondria and chloroplast 2. Similar shape and structure of prokaryotes and resulting mitochondria and chloroplast 3. Presence of double membrane of previously mentioned cells
• Similarities between eukaryotes and prokaryotes include: Presence of DNA for protein synthesis. Presence of Ribosome in cytoplasm, Common metabolic routes including glycolysis, lipid synthesis and protein synthesis. Both contain selectively permeable cell membranes. Both can have cell walls although they vary in structure. Nuclear region is surrounded by cytoplasm in both
• Eukaryote cell wall is plant cell wall. Prokaryote cell wall is made up of peptidoglycan
• Prokaryote cells hold their DNA in the form of one round chromosome found in the nucleoid. It is not surrounded by a membrane and is weakly associated with protein. The cytoplasm only contains organelle ribosome due to undifferentiated cytoplasm. They are very small, being of similar size of mitochondria and chloroplast in eukaryotes. The cell wall is made up of peptidoglycan ( carbohydrates and proteins). Flagella controls movement.
• In the prokaryote cell the flagella is made up of flagellin