CH 3 SG Flashcards
2 parts of cell theory
(unifying principle of biology/cells are highly organized)
-Every living organism is composed of one or more cells
-All cells living today came from a preexisting cell
Microscope importance
(they allow us to see things that are too small to see with the naked eye)
Men responsible for first discovering / describing cells
-Cells were first observed by Robert Hooke in 1665.
-Working with more refined lenses, Antoni van Leeuwenhoek later described
– blood,
– sperm, and
– organisms living in pond water
Light microscope (LM)
Specimens can be magnified up to 1,500 times the actual size of the specimen (LM limit of resolution ~ 0.2μm)
Cell size
(It’s limited)
• be large enough to house “stuff”
• remain small enough to allow for a surface-to-volume ratio that will allow adequate exchange with
the environment.
Structure and functions of cell membranes (fluid mosaic model)
a flexible, fluid bilayer of phospholipids with various proteins embedded within, creating a mosaic-like appearance where the proteins can move laterally within the membrane, allowing for diverse functions like transport and cell signaling
Importance of compartmentalization in eukaryotic cells
(It is efficient) preventing interference in different biochemical pathways enhancing the cell’s functionality
Chloroplasts structure
have a complex system of stacked, disc-like sacs called thylakoids within their inner membrane
Mitochondria and chloroplasts - Endosymbiotic Theory
(They both have DNA/mitochondria and chloroplast are similar to bacteria in size and structure)(Explanation of the evolution of eukaryotic organelles by phagocytosis of prokaryotes)
The eukaryotic host cell has the ability to utilize oxygen/synthesize organic food when the prokaryote was taken up and not destroyed after the two live together cooperatively
Structure and function of the cytoskeleton
provides structural support, maintains cell shape, organizes organelles, and facilitates cell movement by acting as a track for intracellular transport
magnification
is the increase in the apparent size of an object
resolution
is a measure of clarity (the ability to
show two close objects as separate)
Electron microscope (EM)
Instead of light, EM uses a beam of electrons
• Electron microscopes
– have resolution ~ 50pm
– can magnify up to 10,000,000 times
Scanning electron microscopes
(SEM)
Scans cell surfaces
Transmission electron microscopes
(TEM)
internal cell structure
Surface-area-to-volume ratio
(one big cell is not efficient) ratio of a cell’s outside area to it’s internal volume; the relationship limits the maximum size of a cell
Benefits of multicellularity
(increase the size without its limitations) the ability to grow larger, increased complexity due to cell differentiation, better adaptation to diverse environments, improved predator avoidance, and longer lifespans
Phospholipid molecules structure and properties of cell membranes
-primary building blocks of cell membranes
-forming a lipid bilayer structure due to their amphipathic nature
-a hydrophilic (water-loving) head group containing a phosphate molecule
-two hydrophobic (water-hating) fatty acid tails
Cell Wall
Protects the cell, makes it fim. Provides support and protection, only found in plant cells
Cell Membrane
Seperates the cell from other cells, controls what enters and/or leaves the cell
Vacuole
Storage areas for food, minerals, and waste, mostly filled with water, and helps the plant with support. The plant cell has one.
Nucleus
Body in the center of a cell that contains RNA and DNA. Is the control center of the cell and is responsible for activities like reproduction and growth.
Nucleolus
(dark-staining, spherical body in the nucleus that produces ribosome subunits) In the Nucleus, contains RNA (ribosomal RNA (rRNA))
Chloroplast
Contains chlorophyll, site of photosynthesis
