BIOL 111 1st EditionExam # 1 Study Guide Lectures: 7-13Lecture 7 (February 6)Cells- Prokaryotic Cell (“before the nucleus”)- The DNA is not contained in a membrane enclosed region, instead it is concentrated in an area called the nucleoid- Cell Wall – maintains structure and protects from outside damage- Fimbriae – attaches the surface of prokaryotes to other prokaryotes- Capsule – jellylike outer coating - Flagella or Cilia – used for locomotion- Eukaryotic Cell (“true nucleus”)- The DNA is contained in a membrane enclosed nucleus - These cells are generally much larger than Prokaryotic cells (and size relates to function)- Endoplasmic Reticulum (smooth ER does not have ribosomes, rough ER has ribosomes)- Golgi Apparatus – sorts and transports proteins - Mitochondria – makes ATP by cellular respiration - Peroxisomes – convert hydrogen into hydrogen peroxide and then to water- Cytoskeleton – reinforces cell’s shape and movement  Unique to animals cells (not in plant cells): Lysosomes, Centrosomes, Flagella- Lysosomes – digestive organelle where macromolecules are hydrolyzed- Centrosomes – occurs in triplets and made of centrioles and microtubules - Flagellum or cilia – used for locomotion Unique to plant cells (not in animal cells): Chloroplasts, Central Vacuole, Cell Wall, andPlasmodesmata- Chloroplasts – where photosynthesis (conversion of light to energy) occurs- Cell Wall – maintains cell shape and protects from mechanical damage- Plasmodesmata – channels that connects cytoplasms of adjacent cells - Central Vacuole – in older plants that use it for storage and waste breakdown- Both Prokaryotic and Eukaryotic Cells- Plasma Membrane – functions as a selective barrier that allows passage of oxygen and nutrients into the cell and waste out of the cell.- Cytosol – a semifluid, jellylike substance in which subcellular components are suspended.- All cells contain ribosomes to make proteins and chromosomes to carry genes in the form of DNA.Endosymbiont Theory- This theory states that an early ancestor of eukaryotic cells engulfed a prokaryotic cell, forming a relationship with the host cell in which it was engulfed, becoming an endosymbiont (a cell living within another cell)- When they split up into single organisms, one eukaryotic cell had a mitochondria and the other eukaryotic cell (that took with it the photosynthetic prokaryote cell) had chloroplasts.- Mitochondria and Chloroplasts display similarities with bacteria- Like prokaryotes, mitochondria and chloroplasts have double membranes, they contain ribosomes and circular DNA attached to the inner membrane, and finally they are autonomous (semi-independent) organelles that grow and reproduce withinthe cell Lecture 8 (February 11)CytoskeletonIt reinforces cell shape, functions in cell movement, components are made of protein- Microtubules- the thickest (hollow tubes) of the three types of cytoskeleton fibers- it is made up of tubulin (a dimer, molecule made up of two subunits)- Functions: maintain cell shape and support the cell, serve as motility (as cilia or flagella, where the microtubules are arranged in a 9+2, 9 doublets forming a ring, and 2 single microtubules at the center), guide secretory vesicles from Golgi apparatus to the plasma membrane, separation of chromosomes during cell division [they grow out of centrosomes and within the centrosome is centrioles (composed of nine sets of triplet microtubules arranged in a ring), before an animal cell divides, the centrioles replicate]- Microfilaments- These are the thinnest of the three cytoskeleton fibers- It is composed of actin (in a twisted double chain) - Functions: Maintains and changes cell shape, responsible for muscle contractions (myosin and actin sliding past one anther), cytoplasmic streaming (circular flow of cytoplasm within cells), cell motility(pseudopodia – cellular extensions), and cell division (cleavage furrow formation)- Intermediate Filaments- Larger than microfilaments, smaller than microtubules (hence “intermediate”)- Composed of Keratin that are supercoiled into thick cables- Functions: Maintain cell shape (tension bearing elements), anchorage of nucleus andother certain organelles, and formation of nuclear lamina (lines the interior of the nuclear envelope)Membrane Structure and Function- The plasma membrane exhibits selective permeability, allowing some substances to cross more easily than others- Nonpolar molecules [i.e. gases (CO2, N2, O2)] are hydrophobic and dissolve easily and cross membranes easily, without any help.- Polar molecules (i.e. glucose) and Ions (i.e. Na+, K+, Cl-) do not pass the membrane easily and therefore require help of transport proteins. - They are made up of phospholipids (lipids and proteins) bilayer (two layers) that are amphipathetic (have a hydrophobic and a hydrophilic region)- Membranes are made up of a mosaic of proteins, the two major ones are:- Integral proteins – (intrinsic) are embedded in the membrane. Most are transmembrane proteins that span the membrane using alpha helices. And serve a variety of functions including transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining, and attachment to the cytoskeleton and extracellular matrix (ECM) - Peripheral proteins – (extrinsic) loosely associated with the membrane or integral proteinsLecture 9 (February 13)Transporting across a Membrane- Passive Transport is diffusion of a substance across a membrane with no energy investment (go with the flow of concentration gradient)- Diffusion – is the tendency of molecules to spread out evenly into the available space(in the absence of other forces, a substance will diffuse from where it is more concentrated to where it is less concentrated)- Facilitated Diffusion – transport proteins speed up the passive movement of molecules across the plasma membrane - Osmosis is the diffusion of water across a membrane - Tonicity is the ability of a solution to cause a cell to gain or lose water - Hypotonic solution – the solute concentration is lower outside the cell than on the inside, therefore a substance will flow to the inside of the cell (turgid), ideal for plants which are protected from bursting (like an animal cell would) by the cell wall - Isotonic solution – the solute concentrations are equal (flaccid), ideal for animal cells- Hypertonic solution – the solute concentration is