A Introduction Part 1

Parts of the Cell Hooke: discovered first cell Anton van Leeuwenhoek: discovered living cell Cell Theory • Matthias Schleiden (plant cells) – living things are made of cells • Theodor Schwann (animal cells) – cells are the basic structure of life • Rudolph Virchow – cells come from pre-existing cells 1. All living things are composed of one or more cells 2. Cells are organisms’ basic units of structure and function 3. Cells only come from existing cells Organelle: cell component that performs specific functions in the shell Eukaryotes: cells that contain a nucleus and membrane-bound organelles Prokaryotes: cells that lack nuclei and membrane-bound organelles Cells • Most roughly spherical or cubodial • Ratio b/w surface area and volume limits size o nutrients and waste have to diffuse through surface o the larger the cell, the larger the surface area needed to maintain it o as a cell grows, the volume increases more rapidly than the surface area 1. Outer Boundary o Cell membrane o Plasma membrane o Cell wall [plants] 2. Interior Substance o Fluid o Cytoskeleton o Organelles 3. Control Centre o Nucleus o Plasmids (free-floating DNA)

Component Ribosome Endoplasmic Reticulum Golgi Apparatus Mitochondrion Lyosomes

Microtubules & Microfilaments Cilia & Flagella

Nucleus

Cell Wall Vacuole(P) & Vesicles(A) Plastid Chloroplast Leucoplasts Cell Membrane

Description Where protein synthesis takes place Membrane system in the cytoplasm; covered with ribosomes; many ribosomes = rough E.R.; few or no ribosomes = smooth E.R. Processing, packaging, and secreting organelle Site of aerobic respiration; where Adenosine Triphosphate (ATP) is formed; have their own DNA; have 2 membranes Contain digestive enzymes; small and spherical; surrounded by single membrane; digest food particles, disease-causing bacteria captured by white blood cells, and worn-out and broken cell parts; aid in early development Long, slender protein tubes (microtubules) and fine protein threads (microfilaments) help to shape and support cells; collectively they form the cytoskeleton; specialized microtubules (spindle fibbers) aid in movement of chromosomes during cell division Structures that extend out from the surface of the cell and function in movement; cilia are short, hair-like extensions that occur in large numbers on the surfaces of some cells; flagella are whip-like, longer than cilia, and occur singly or in pairs Where nucleic acids are synthesized; directs cell activities; surrounded by nuclear envelope (double membrane); has ‘nuclear pores’ through which substances enter and leave; most contain nucleolus which synthesizes ribosomes and partially assembles them Surrounds cell membrane; provides support and protection; primarily made of cellulose; has pores to allow molecules to pass through; secondary wall forms when cell stops growth Stores fluid and waste; store enzymes in plant cells; takes up most of the cell’s volume in plant cells converts solar energy to chemical energy and then stores it Contain green pigment called chlorophyll that absorbs sunlight; synthesize and store pigments Store food such as starches , proteins, and lipids Sometimes called plasma membrane; gives shape and flexibility to the cell; selectively permeable/semipermeable membrane; composed of 2 layers of molecules; each layer made up of a sheet of lipids (a lipid molecule has a carboxyl group as a “head” and a hydrocarbon chain as a “tail”

A or P cells A/P A/P A/P A/P A

A/P

A

A/P

P A/P P P P A/P

Fluid Mosaic Model

Lipid molecules arranged so heads form outside of membrane and tails from inside of membrane

Protein molecules are embedded in the lipid layers Cellular Respiration C6H12O2 + 6O  6CO2 + 6H2O + ATP (glucose) (energy) ATP = Adenosine Triphosphate ADP = Adenosine Diphosphate ATP = ADP + P + energy Photosynthesis Occurs in chloroplast CO2 + H2O 

O2 + C6H2O6

(starch)

light energy

Multicellular Organization Tissue: group of similar cells that carry out a common function Organ: several types of tissue that interact to perform a specific function Organ System: made up of organs that work together to perform a set of related tasks Tissues/Organs/Organ Systems in Plants • Dermal tissue system forms outer layer of plant • Ground tissue makes up the bulk of roots and stems • Vascular tissue is the water transport system of the plant • Organs: roots, stems, leaves Colonial Organisms Group of more or less similar cells that live together in closely connected groups

Cell Transport 1. Passive Transport – doesn’t require ATP 2. Active Transport – uses ATP Homeostasis: biological balance between cells, tissues, organs, organisms and their environment Concentration Gradient: the difference in concentration of a substance across space Equilibrium: state that exists when concentration of a substance is the same throughout a space Turgor Pressure: water pressure within a cell Plasmolysis: the shrinking or wilting of a cell from low turgor pressure Cytolysis: the intake by a cell of so much water that it bursts Contractile Vacuoles: collect excess water and then contract, squeezing the water out of the cell Solute: substance present in lesser quantity in a solution Solvent: substance present in greater quantity in a solution *Direction of osmosis depends on the concentration Passive Transport 1. Diffusion: movement of particles from area of high concentration to low concentration o Selectively permeable membrane chooses what goes through (ex. O2, H2O, fats) 2. Osmosis: movement of water from high to low concentration A) Isotonic -Equal concentration of H2O inside and outside the cell

B) Hypertonic -Inside has more H2O than outside -Cell shrinks – plasmolysis

C) Hypotonic -Outside has more H2O than inside -Cell grows until it explodes -Lysis -Hemolysis (red blood cells) -Plants have cell wall that keeps it from expanding -Turgor pressure -Keeps plant upright

Facilitated Diffusion “Assisted diffusion” for molecules that are too large to pass through the membrane (ex. glucose) 1. Binding

2. Protein Changes Shape

3. Release

Diffusion Through Ion Channels Ion Channels: proteins that transport ions (ex. Na1+, K1+, Ca2+, Cl1-) Active Transport Uses ATP; goes from low concentration to high concentration 1. Cell Membrane “Pumps” o Works just like facilitated diffusion using protein channels 2. Endocytosis o Cell ingests external fluids, macromolecules, large particles, & other cells

o Pinocytosis: transport of solutes or fluids o Phagocytosis: transport of large molecules of cells 3. Exocytosis o Opposite of endocytosis