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Chapter 6-7 (Concept 6.4 (Vacuole (Vacuole - large vesicle that has…
Chapter 6-7
Concept 6.4
Endomembrane System
Endomembrane system - carries out many tasks for the cell, including synthesis and transportation of proteins, metabolism and movement of lipids, and detox of poisons
Vesicles - sacs made from the membrane, used to carry proteins
The Endomembrane System includes Nuclear Envelope, ER, Golgi Apparatus, Lysosomes, Vesicles, Vacuole, Plasma Membrane
ER
Endoplasmic Reticulum (cisternae) - network of membranous tubules and sacs within the cytoplasm. Functions of the ER also include synthesis and transportation of proteins, metabolism and movement of lipids, and detox of poisons
Smooth ER
- Lacks ribosomes
- Enzymes are important for synthesis, which include oils and steroids. Sex and steroid hormones are produced in animal cells.
- More enzymes help with detoxing poisons. Usually involves adding hydroxyl to molecules so it can exit the body easier.
- Many drugs include proliferation, which allows a higher rate of detox
- Stores calcium ions and is activated through a muscle cell, which then carries the ions by vesicle
Rough ER
- Ribosome studded on the surface
- Polypeptide chains grow from bound ribosomes, which is threaded into the ER lumen
- Glycoproteins - proteins covalently bonded with carbohydrates
- Transitional ER uses transport vesicles, which are simply vesicles in transit that bring secretory proteins
- Membrane factory for cell
- Grows in size when proteins and phospholipids are added
Golgi Apparatus
Golgi apparatus - transport vesicles travel to the warehouse: receives, sorts, ships, and manufactures products of the ER, such as proteins. The Golgi is built similarly to the ER, but they both function differently
Two faces of the Golgi:
Cis face - receiving side, generally facing the ER to receive proteins through the transport vesicles
Trans face - shipping side, allows vesicles to detach and travel to other parts of the cell
The cisternae in the Golgi functions with the cis and the trans, which carry and modify cargo as they move. Before the vesicles disperse, the Golgi packages the proteins and "labels" them to "mail". Once that process is complete, they are released to their appropriate part of the cell.
Lysosomes
Lysosome - sac of lysosomal enzymes used to digest hydrolytic enzymes such as simple sugars, amino acids, and monomers that will pass the cytosol to become nutrients
Phagocytosis - process amoebas and others use to eat by digesting smaller food particles. A food vacuole is formed to link with lysosomes.
Autophagy - recycling cell's material; damaged organelles pass through membranes to be reused and the cells are able to renew themselves
Vacuole
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Food vacuole - membrane sac where food is stored, broken down, and nutrients is extracted
Contractile vacuoles - regulating water concentration; pumps excess water from the cell through osmoregulation
Central vacuole - found in mature plant cells; develops multiple smaller vacuoles; also absorbs water, generally held for plant cells
Cell sap - solution found in vacuole, which is plant cell's main repository of inorganic ions
Concept 6.2
Prokaryotic Cells
These cells do not have a membrane-bound nucleus, but DNA is concentrated in a nucleoid
Eukaryotic Cells
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Specific functions of a cell's metabolic support includes phospholipid layers attaching to surfaces of proteins. Enzymes also work with mitochondria during cellular respiration
Both Cell Types
All cells are bounded by a cell (plasma) membrane, contain cytosol (plasm) and chromosomes, and protein-making ribosomes
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Plasma membrane - barrier that determines what enters (nutrients and energy) and exits (waste) the cell
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Concept 6.5
Mitochondria
Mitochondria - found in almost all eukaryotic cells; # is based on the metabolic activity cellular respiration, metabolic process used oxygen to form ATP (energy)
Cristae - increases the surface area of the inner membrane, allowing for faster production of ATP because there are more places to perform the process.
Consists of mitochondrion matrix, which is enclosed by the inner membrane. Matrix contains enzymes, ribosomes, and DNA
Movement of Mitochondria:
- Moves around
- Changes shape
- Fuses or divides in two
Chloroplasts
Chloroplast - found in plant cells and algae; photosynthesis - converting solar energy to chemical energy to form glucose (sugar)
Contains chlorophyll - green pigment used with enzymes and other molecules to produce sugar during photosynthesis
- Thylakoids - located inside the chloroplast, connected sacs stacked on one another (poker chips)
- Granum - each individual stack of thylakoids
- Stroma - fluid outside, containing the DNA and enzymes
Photosynthesis is able to happen through these three divided compartments: intermembrane space, stroma, and thylakoid space
Plastids - plant organelles such as amyloplast, which stores starch and chromoplast, which gives objects their pigment
Endosymbiont Theory
Ancestor eukaryotic cells become oxygen-using nonphotosynthetic (absent chloroplast) eukaryotes, which over time then become photosynthetic (present chloroplast)
Concept 6.1
Microscopy
Invented in 1590, microscopes were utilized to examine cells at a higher magnification. In 1665, Robert Hooke discovered cell walls.
Three Important Parameters:
Magnification - ratio of object's image to size to its real size; microscopes can magnify about 1,000 times the real size
Resolution - measures clarity of image
Contrast - difference in brightness of the specimen; methods include staining or labeling
Different Microscopes:
Light Microscope - visible light is passed through the specimen and through glass lenses
Electron Microscope - focuses a beam of electrons through or onto the surface
Scanning Electron Microscope - electron beam used to scan surface that allows signal to transmit through electrons
Transmission Electron Microscope - studies internal structure of cells; enhances electron density
Cell Fractionation
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Centrifuge - used to spins test tubes holding disrupted cells at increasing speed. After this process, cells settle at the bottom of the tubes and are examined separated
Concept 6.3
Nucleus
Nucleus - contains most DNA and information in eukaryotic cells; surrounded by a double membrane nuclear envelope, which separates the nucleus from the cytoplasm
Pore complexes line up at each pore by regulating entry and exit of RNA and proteins, similar to the function of the cell wall
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Chromosomes - structures that carry genetic information, containing one long strand of DNA; formed into an "X" shape
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Nucleolus - fibers joining to chromatin; ribosomal RNA are synthesized. Nucleus directs protein synthesis by mRNA - transporting ribosomes through the cytoplasm
Ribosomes
Ribosomes - made of ribosomal RNAs and proteins, carry out protein synthesis. High rate protein synthesis cells generally have larger #s
"Free ribosomes" are found in the cytosol, while bound ribosomes are attached, mainly to the outside of the rough ER. Free ribosomes are typically made to function within the cytosol and roam freely, while the bound ribosomes link with the rough ER insert into membranes, package proteins, or exit the cell