Unt 4 Cells

Question 1

Hooke

Answer 1

• first to use the word “cell”

- looked at cork

Question 2

Schwann

Answer 2

-determined that animals are made of cells

Question 3

Schlieden

Answer 3

-determined plants are made of cells

Question 4

Brown

Answer 4

-saw the nucleus

Question 5

Virchow

Answer 5

-found out that al cells come from previous cells

Question 6

Cell theory

Answer 6

• cells are basic units of structure and function
• cells come from preexisting cells
• cells pass along genetic info (DNA) to future generations

Question 7

Exceptions to the cell theory

Answer 7

• 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)

Question 8

Function of membranes

Answer 8

• 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)

Question 9

Diffusion

Answer 9

• 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

Question 10

Osmosis

Answer 10

• diffusion on water towards areas of higher solute concentrations
• Solute cannot cross the membrane
• passive process
• salt and water

Question 11

Facilitated diffusion

Answer 11

• transport thru a membrane, requires a channel protein
• solute goes from high concentration to low concentration
• passive process
• ex. Glucose into a cell

Question 12

Active transport

Answer 12

• 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

Question 13

Endocytosis

Answer 13

• 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

Question 14

Exocytosis

Answer 14

-vacuoles fuse with plasma membrane and releases particles (waste or enzymes)

Question 15

Lysis

Answer 15

-cell membrane ruptures and all of the contents are released

Question 16

Cytoplasmic streaming (cyclosis)

Answer 16

• 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

Question 17

Light microscope

Answer 17

-resolution of image is limited by the size of the light wavelength

Question 18

Transmission electron microscope

Answer 18

• the wavelength of the election beam is much smaller than the wavelength of light
• better resolution
• specimen needs to be dead

Question 19

Scanning electron microscope

Answer 19

• scans (with electrons) across the surface
• 3D image
• specimen needs to be dead

Question 20

Secretory pathway

Answer 20

-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

Question 21

Von Leeuwenhoek

Answer 21

Saw microscopicceorod thru simple microscope