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BIOLOGY EXAM 2 (CHAPTER 5)
Terms in this set (49)
-cells are the fundamental units of life
-all living organisms are composed of cells
-all cells come from preexisting cells
Two basic types of microscopes?
What is the difference between light and electron microscopes?
electron- resolution is better but only dead cells are visualized
light- you can visualize living cells
This is best observed with an electron microscope. This very thin structure forms the outer surface of every cell, and it has more or less the same thickness and molecular structure in all cells...
what does the plasma membrane consist of ?
-variety of proteins are embedded within bilayer
Roles of plasma membrane
-acts as barrier preventing substances from entering and leaving the cell (non polar molecules cross it more easily)
-allows cell to maintain a constant internal environment(homeostasis)
-communicating with cells and receiving signals
-proteins protruding from it, responsible for binding adjacent cells
Prokaryotic cells don't have...
Eukaryotic cells contain...
plasma membrane is?
-enclosed in the cell
-region where DNA is located
-consist of liquid component, the cytosol (filaments like ribosomes)
-mostly water (dissolved ions)
-complexes of RNA and protein
cell wall located?
located outside plasma membrane
How do some prokaryotic cells swim? & what does this thing do?
flagella: looks like a tiny corkscrew, cause motion of cells
In bacteria, the filament of the flagellum is made up of a protein called...
The flagellum spins like a?
propeller, driving the cell along
capsule does what? and helps cells from?
:protect bacteria from attack by WBC's, help keep cells from drying out
internal membrane contains molecules needed for?
Pili are structures made up of? structure is?
Cytoskeleton is the collective name for protein filaments that play roles in?
cell division or maintaining shape of cell
Ribosomes are factories for...
Function of nucleus in the cell?
-most of cells DNA (DNA replication)
Nucleolus is where______________ begin to be assembled from RNA and proteins
Nucleus is surrounded by integrated structure comprised of two membranes called?
Inside the nucleus, DNA is combined with proteins to form a fibrous complex called? This occurs in the form of exceedingly long, thin threads called?
The Rough ER participates in?
transporting proteins to other locations in the cell
The Smooth ER roles?
-responsible for the chemical modification of small molecules
-site for glycogen degradation
-site where lipids and steroids are synthesized
-stores calcium ions
Golgi A consists of flattened membranous sac called ________ and small membrane enclosed vesicles
Roles of Golgi A?
-receives protein vesicles from Rough ER
-sorts/ packages proteins
-adds carbs to proteins
Primary lysosome originates from? They are sites for the breakdown of ?
Golgi A; food
Primary lysosomes contain_____________ and are the sites where macromolecules are hydrolyzed into their monomers.
Function of mitochondria?
is to harvest the chemical energy of those fuel molecules known as ATP
peroxisomes are small organelles that have single membrane and granular interior containing__________________
Glyoxysomes are found only in plants and its the location where stored__________ are converted into carbs for transport to growing cells
Functions of vacuoles?
Roles of cytoskeleton?
-supports cell and maintain its shape
Three components of cytoskeleton?
Microfilaments have two roles?
-help entire cell or parts of cell move
-determine and stabilize cell shape
microfilaments are assembled from monomers of?
Actin filaments are associated with another protein, the "motor protein" called?
Intermediate filaments have two structural functions that are?
-anchor cell structure in place
-they resist tension
Largest of microfilaments, intermediate filaments, and microtubules are?
Two roles of microtubules?
-form a rigid internal skeleton for some cells
-act as framework along which motor proteins can move structures within the cell
Microtubules are assembled from dimers of the protein__________?
Dimers are made up of two?
Microtubules help control arrangement of the?
cellulose fibers of cell wall
What is the motion of cilia and flagella?
sliding of the microtubule doublets past one another
Dynein moles bind between two?
neighboring microtubule doublets
Another protein _____________, cross links the doublets and appears to limit how far the doublets can slide. this causes the cilium or flagellum to bend
Other motor protein, called __________ carry protein vesicles. These proteins bind to the organelle and "walk" it along the microtubule by a repeated series of shape changes.
Kinisin moves them toward ____________ end and dyne moves them toward ____________ end.
Why is a cell so small?
in order to maintain a large surface area to volume ratio
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