Cell Structure Flashcards
Define Magnification
The number of times larger an image appears compared to its actual size.
Define Resolution
The ability to distinguish between 2 separate points in an image.
Describe a Laser Confocal Light Microscope
You can use a live specimen.
Has colour and 3D image.
High Depth Selectivity.
Lower magnification and resolution than SEM/TEM [but still quite high]
Disadvantages could be that it is a slow process.
Describe a Scanning Electron Microscope.
100x-100,000x MAG and 3-10nm RES
Electrons are fired at specimens and bounce off the surface. It is then detected by a computer and the image is built up.
Produces a 3D image.
High, but lower mag and res than TEM.
Cant use live specimens.
No colour.
Describe a Transmission Electron Microscope
100x-2,000,000x MAG and 0.2-1.0nm RES
Electrons are fired through the specimen and detected by a computer.
Produces a 2D image.
High mag and res.
Cant use live specimens, or thin ones.
Long process.
No colour produced.
Nucleus
Contains chromatins. [DNA]
Controls the reactions of the cell.
Has a nuclear envelope and nuclear pores.
Nucleolus
Contains ribosomal RNA
Ribosome synthesis.
Ribosomes
Protein Synthesis
Rough Endoplasmic Reticulum
Transports and packages proteins [processes proteins].
Has ribosomes attached to it.
Proteins are produced are used for activities outside that cell.
Smooth Endoplasmic Reticulum
Lipid, phospholipid, steroids synthesis. [cholesterol]
Golgi Apparatus
Modifies and repackages protein into vesicles for them to leave the cell.
Mitochondria
Has a inner membrane fold called cristae.
Matrix formed by cristae contains enzymes needed for respiration.
Has some smaller pieces of DNA.
Produces ATP, involved in aerobic respiration.
Microvilli
Out folding of the plasma membrane.
Increases the surface area for movement of molecules.
Centrioles
Bundles of microtubules.
Produces spindle fibres for cell division
Lysosome
Membrane-bound sac of enzymes.
Hydrolytic enzymes.
Cellulose Cell Wall
Structural support for plant cell.
Vacuoles
Has a membrane called tonoplast.
Helps keep cell turgid.
Chloroplast
Contains chlorophyll which is used for photosynthesis.
Has stack of thylakoids called grana.
Thylakoids contains the chlorophyll.
Plasmodesma [ta]
Allows exchange of water and miracle between cells.
Pores linking plant cells.
Middle Lamella
Contains pectin [glue].
Sandwhiched between cellulose.
Microfilament
Long, thin, flexible threads.
5nm
Made from actin.
Used in cell movement, division and for muscle contraction.
Microtubules
Thick, cylindrical tubes.
25nm
Made from tubulin.
Movement of organelles around cell, requires molar protein and ATP.
9+3 arrangement in centrioles.
Intermediate fibres
“rope-like” proteins that span the cell.
Variable diameter.
Made from Elastin collagen.
Cell scaffolding and mechanical strength.
Prevents cell from collapsing and hold organelles in place.
How are proteins produced?
mRNA [copy of the DNA code] made in the nucleus. mRNA then leaves the nucleus through the nuclear pore, and goes to the ribosomes that are attached to the RER.
Proteins are produced and are then folded and packaged as it moves along the RER. The proteins then leave the RER via vesicles and fuses to the cis-face of the Golgi apparatus, it is then repackaged and modified into vesicles. It then leaves the Golgi via the trans-face, and fuses to the plasma membrane. The materials of the proteins are then released out of the cell. [exocytosis]
