Biology Chapter 4 Flashcards
Cell Theory?
(1) All organisms derive from pre existing cells
(2) Cell is basic unit of life
(3) All organisms are made form one or more cells
Scanning electron microscopes (SEMs):
Focus a beam of electrons onto the surface of a specimen
Transmission electron microscopes (TEMs):
Focus a beam of electrons through a specimen to study
the internal structure of cells.
Why are cells small?
Most cells are small due to reliance on diffusion of substances in and out of cells
How is Rate is Diffusion affected
– Surface area available – Temperature – Concentration gradient – Distance – Size of diffusing substance
Ratio for maintaining Homeostasis? Hint (High what: to what ratio)
CELLS MUST HAVE A HIGH TO SURFACE AREA TO VOLUME RATIO TO MAINTAIN HOMEOSTATIS
How do cells maintain a high surface area to volume ratio?
Small size
Large but slender (Nerve Cell)
Microvilli (in intestines)
Microvilli
Increase surface area for absorption,
Ribosomes
Made up of large subunit and subunit
Ribosomes assemble amino acids into proteins
Mitochondria
Cellular respiration happens here
“Power house of cell”
Have own DNA
Chloroplast
Contain chlorophyll for photosynthesis
Have own DNA
How does Mitochondria and Chloroplast make energy?
Mitochondria makes energy through Aerobic respiration
Chloroplasts makes energy through photosynthesis
What is Endosymbiotic theory?
Used to be prokaryotic cells that became trapped in evolving eukaryotic cells
Evidence of Endosymbiotic Theory?
Evidence:
Contain plasmid DNA and ribosomes
Size is similar to bacteria
Divide by binary fission
Endomembrane System
Nuclear envelope Endoplasmic reticulum Goldi apparatus Lysosome Vacuoles and vesicles Plasma membrane
