Cell and Molecular Biology

• The endoplasmic reticulum is a network of membranes involved in the synthesis of proteins and lipids.
• Cell and molecular biology is ____

  reductionist
• spectacles were first made in Europe in

  13th century
• first compound (double lens) light microscope was constructed by the

  16th century
• Robert Hooke used cork, examined it with a microscope, and described it as similar to a honeycomb due to its little porous appearance
• _____ constructed simple microscope

  Antonie van Leeuwenhoek
• Antonie van Leeuwenhoek was the first to examine a drop of pond water and called what he saw as 


  animalcules
• First to describe various forms of bacteria

  Antonie van Leeuwenhoek
• Cell Theory 1. All organisms are made up of one or more cells. 2. The cell is the structural unit of life. 3. Cells can only arise from division of pre-existing cells
• Matthias Schleiden concluded that plants were made of cells and that the plant embryo arose from a single cell
• Theodor Schwann concluded that the cells of plants and animals are similar structures and proposed two tenets of the cell theory (no. 1, 2)
• Schleiden and Schwann both agreed that cells could arise from noncellular mate
• Rudolf Virchow proposed the third tenet of Cell Theory
• Cells can be removed from a plant or animal and cultured in a laboratory where they will grow and reproduce
• George and Martha Gey of John Hopkins University began the first culture of human cells
• HeLa cells were obtained from the malignant tumor of Henrietta Lacks
• 9 Properties of Cells

  1. Cells are highly complex and organized
  2. Cells possess a genetic program and the means to use it
  3. Cells are capable of producing more of themselves
  4. Cells acquire and utilize energy
  5. Cells carry out a variety of chemical reactions
  6. Cells engage in mechanical activities
  7. Cells are able to respond to stimuli
  8. Cells are capable of cell regulation
  9. Cells evolve
• DNA duplication occurs with an error rate of <1 mistake every 10 million nucleotides. Most is quickly corrected by a repair mechanism
• Organisms are built according to information encoded in a collection of genes, which are constructed of DNA
• The molecular structure of genes allows for changes in genetic information (mutation) that lead to individual variation
• Cells reproduce by division
• All utilized energy arrives in the form of electromagnetic radiation from the sun. The energy of light is trapped by pigments in the photosynthetic cells
• Cells function like miniaturized chemical plants. All chemical changes in cells require enzymes which greatly increase the reaction rate.
• Metabolism is represented by the sum total of the chemical reactions in a cell
• Many activities in the cell are initiated by changes in the shape of motor proteins
• Motor protein is one of the many types of molecular machines employed by cells for mechanical activities. Ex. Myosin for actin filaments whereas kinesin and dynein for microtubules.
• Cells within a multicellular plant or animal respond to stimuli less obviously than unicellular
• Receptors interact with substances in the environment in highly specific ways and act as a pathway.
• Cells are robust because they are protected from dangerous fluctuations in composition and behavior
• Hans Driesch completely separated the first 2 or 4 cells of a sea urchin embryo and the isolated cells developed into a normal embryo (although smaller)
• Last Universal Common Ancestor (LUCA) is the single, common ancestral cell
• 2 Basic Classes of Cells: Prokaryotic and Eukaryotic
• Prokaryotic and Eukaryotic Cells are distinguished by size and contained organelles or types of internal structures. It represents one of the most fundamental evolutionary divisions in the biological world
• Prokaryotic cells include bacteria
• Eukaryotic cells include protists, fungi, plants, and animals.
• Cyanobacteria almost certainly appeared 2.4 billion years ago when the atmosphere became infused with molecular oxygen (O2) which is a by-product of photosynthetic activity of prokaryotes
• The shared properties reflect the fact that eukaryotic cells almost certainly evolved from prokaryotic ancestors. Both share an identical genetic language, a common set of metabolic pathways, and many common structural features
• Nucleoid is where the genetic material of a prokaryotic cell is present. A poorly demarcated region of the cell that lacks a boundary membrane to separate it from the surrounding cytoplasm
• Nucleus is present in eukaryotic cells. It is a region bounded by a complex membranous structure called the nuclear envelope
• • prokaryotic (pro - before, karyon - nucleus)
  • eukaryotic (eu - true, karyon - nucleus)