Unt 4 Cells Flashcards
Hooke
- first to use the word “cell”
- looked at cork
Schwann
-determined that animals are made of cells
Schlieden
-determined plants are made of cells
Brown
-saw the nucleus
Virchow
-found out that al cells come from previous cells
Cell theory
- cells are basic units of structure and function
- cells come from preexisting cells
- cells pass along genetic info (DNA) to future generations
Exceptions to the cell theory
- where did the first cell come from?
- viruses (made of only proteins and DNA/RNA…are not cells)
- mitochondria and chloroplasts contain their own genetic info (DNA)
Function of membranes
- free passage of water
- selective transport of molecules through channel proteins
- reception of information (glycoproteins and glycolipids)
- cell information/identity (glycoproteins and glycolipids)
- cell to cell adhesion (proteins)
- attachment of cytoskeleton (to proteins)
- enzyme activities (proteins in membrane)
Diffusion
- net movement of molecules from a high concentration to a low concentration
- passive process (no energy required)
- balances the concentration gradient
- O2, CO2, Urea (NH2CONH2) go through diffusion
Osmosis
- diffusion on water towards areas of higher solute concentrations
- Solute cannot cross the membrane
- passive process
- salt and water
Facilitated diffusion
- transport thru a membrane, requires a channel protein
- solute goes from high concentration to low concentration
- passive process
- ex. Glucose into a cell
Active transport
- transport across a membrane against a concentration gradient using a protein (low concentration to high concentration)
- requires energy, needs ATP
- proton pump (H+), occurs in mitochondria and chloroplasts
- protons forced to build up on one side of the membrane
- Sodium-Potassium pump - energy is used to pump Na out of K into nerve cells
Endocytosis
- taking particles into a cell
- pinocytosis-the engulfing of dissolved particles (small particles)
- phagocytosis-the engulfing of large particles or entire cells
- particles go into indentation–> bubble forms in cytoplasm –> fuses w/ a lysosome–> molecules broken down into subunits by enzymes, subunits used to build cell structures and gain energy
Exocytosis
-vacuoles fuse with plasma membrane and releases particles (waste or enzymes)
Lysis
-cell membrane ruptures and all of the contents are released
Cytoplasmic streaming (cyclosis)
- movement of the cytoplasm (protein paddles)
- nutrients, enzymes, organelles, etc are not efficient if cells are too large, or if inside of the cell is stationary
- ex. Anacharis (elodea), one large vacuole, cytoplasm, and chloroplasts, chloroplast movement is visible bc of cyclosis
Light microscope
-resolution of image is limited by the size of the light wavelength
Transmission electron microscope
- the wavelength of the election beam is much smaller than the wavelength of light
- better resolution
- specimen needs to be dead
Scanning electron microscope
- scans (with electrons) across the surface
- 3D image
- specimen needs to be dead
Secretory pathway
-DNA to mRNA, mRNA exits nucleus and goes to ribosome, ribosome puts amino acids in order (protein), protein goes to Golgi and gets rearranged/packaged, vesicle takes protein to fell membrane and fuses, the protein is released, exocytosis
Von Leeuwenhoek
Saw microscopicceorod thru simple microscope
