Biology 224, Chapter 4 - Paul Sattler
Terms in this set (74)
3 parts of the cell theory
1. Cells are the fundamental unit of life
2. all organisms are composed of cells
3. all cells come from preexisting cells
Why are cells so small?
Because that means they have a larger surface area.
What does cell volume determine?
What does cell surface area determine?
Rate of transport in and out of the cell
Makes something larger
Makes something clearer (minimum distance between two objects)
Light microscope (definition; resolving power)
Uses light passing through an object to view it; 200 nm
Transmission Electron Microscope (definition; resolving power)
Uses an electron beam passing through an object. (Cells are killed and stained with heavy metals to block the electron beam); 0.2 nm
Scanning electron microscope
Obtains more of a 3D view (coats the surface with heavy metal stains and uses an electron beam to scan the surface); 1 nm
(Eubacteria and Archaebacteria) Lack membrane-bound organelles, have a simple structure, are generally small
Prokaryotic plasma membrane structure and function
(single membrane) and regulates transport
Prokaryotic nucleoid structure and function
(aqueous) and heredity
Prokaryotic cytoplasm structure and function
(aqueous) and biochemical reactions
Prokaryotic ribosomes structure and function
(solid- RNA and proteins) and protein synthesis
Prokaryotic cell wall structure and function
(Peptidoglycan membrane) and protection/support
Prokaryotic capsule structure and function
(polysaccharides) and protection/hydration
Prokaryotic flagella structure and formation
(solid-proteins) and movement
Have membrane-bound organelles, are complex, and larger
Aqueous mixture with proteins and enzymes
Why are enzymes in the cytoplasm important?
they are often first reactions of important metabolic pathways like glycolysis and fatty acid synthesis
Metabolic breakdown of sugar into free energy (ATP)
Series of fibrous organelles that provide an internal skeleton; the fibers are made of protein monomers
Large, long hollow tubes of Tubulin contributing to the cytoskeleton; 25 nm; have a + and - end
What controls microtubule growth?
Centrioles and basal bodies
What are microtubule "roads"? and how do they work?
Vesicles and chromosomes move along roads using molecular "motors" (Kinesin)
How to microtubules move?
With cilia and flagella (locomotion); and mitotic spindle (for moving chromosomes during cell division)
Intermediate filaments (structure)
50+ types; thin, twisted rods of Keratin, found in specialized cells; 8-12 nm
Intermediate filaments (function)
Stable (don't grow and shrink); maintain cellular shape and provide mechanical strength to the cell.
Where are intermediate filaments found?
They line the inside of nuclear membrane to anchor pores
Thin rods of actin proteins (in single filaments, bundles or networks); 7nm
1. cellular movements (muscle contraction, cytoplasmic streaming, and pseudopod formation)
2. Cytoplasmic division (cytokinesis) dividing cells during mitosis/meiosis
3. support plasma membrane; provide shape and strength to cell
Near plasma membrane
Nucleus (structure; function)
double membrane, with thousands of small pores; stores DNA
What surrounds each pore of the nuclear membrane?
8 large protein granules
Nuclear localization signal
a short peptide chain found on the proteins targeted for the nucleus
Consists of genes that code for rRNA
necessary for ribosome construction
The endomembrane system (definition; members)
A group of functionally interrelated organelles; nuclear envelope, ER, Golgi apparatus, lysosomes, plasma membrane, and vesicles that connect these organelles
single membrane; continuous tubes and sacs that contain lumen; up to 10% of the cell's volume
Has ribosomes (which synthesize proteins in the lumen of the ER)
How can the proteins in the ER alter their functions?
The ER can chemically modify them
What does the ER "tag" vesicles with?
short peptide signals for delivery to various organelles
Some proteins from the ER have an oligosaccharide chain that forms what?
What is the function of the rough ER?
Synthesize glycoproteins and membrane-bound proteins, and proteins designed for various organelles
Smooth ER in comparison to the rough ER
lacks ribosomes and is more tubular than flattened sacs (it is in continuous with sections of the rough ER)
Functions of smooth ER
Detoxification (by making poisons more polar and easy to excrete), has enzymes for glycogen and calcium metabolism; synthesizes phospholipids (membranes) and other lipids (including steroids)
Golgi apparatus structure
Flattened sacs; single membrane surrounding central lumen
vesicles transport protein from where (inside the Golgi body)
ER to cis, medial, then trans Golgi body
Golgi apparatus functions
1. Add/modify carbohydrate portion of glycoproteins
2. Proteolysis (proteases cut proteins into smaller, functional proteins)
3. Concentrate, package and sort proteins before being transported to cellular destinations
Golgi body "pouches"
Large vesicles containing digestive enzymes surrounded by a single membrane
Digestion via hydrolytic reactions
Digestive enzymes (via hydrolytic reactions)
Formed by vesicles containing hydrolytic enzymes forming from the Golgi
formed by the fusion of a primary lysosome and a food vacuole (phagosome)
large and solid subunits composed of 1-3 rRNAs and 20-30 proteins
free in cytoplasm, attached to ER, or inside mitochondria and chloroplasts
similar to large vesicles
1. storage of food/waste materials
2. maintain turgor pressure
Contractile vacuole function
excrete excess water
What are contractile vacuoles found in?
Contain enzymes for specific functions
Contain catalase to degrade hydrogen peroxide (toxic in large quantities)
How are peroxisomes made?
Synthesized as vesicles from the ER
Glyoxisomes function and location
Contain enzymes; convert stored lipids into carbohydrates for growth; found in plant seeds
Endomembrane system; surrounds cell and divides it from the outside environment.
Plasma membrane functions
1. membrane transport (protein transporter)
2. cell signaling (hormones)
3. cell adhesion (proteins)
What do protein transporters do?
transport things through the plasma membrane
Mitochondria and chloroplast (they can divide independently of the cell, contain their own DNA and ribosomes)
Double membrane, two spaces, mitochondrial matrix, cristae
Convert energy in organic molecules into ATP (aerobic respiration)