Mod. 2 Cells Flashcards
nuclear envelope
surrounds the nucleus, separating the nuclear material from the cell cytoplasm.
centrioles
found only in animals cells, and are the attachment points for the spindle tubules during cell division. in pairs.
cell wall
in plants only. a complex of cellulose microfibrils running through a matrix of complex polysaccharides providing support to the cell.`
mitochondria
the site of aerobic respiration
lysosome
a.k.a. suicide bags. They are membrane bound sacts that contain digestive enzymes which can be used to break down old organelles or the cell itself.
smooth endoplasmic reticulum
makes and transports lipids and steroids
nucleus
contains the genetic information in the form of DNA
micro villi
increase the surface area of a cell where appropriate. e.g. the gut
golgi apparatus
where polypeptides are packages for export. the protein is modified by the addition of a carbohydrate chain to form a glycoprotein.
rough endoplasmic reticulum
a series of membrane-bound cavities that act as the intracellular transport system. they are studded with ribosomes.
chloroplasts
site of photosynthesis
nuclear pore
a small hole that allows genetic information to pass from the nucleus to the cytoplasm
ribosomes
site of protein synthesis, where amino acids are joined together to form a polypeptide chain
chromatin
DNA combined with histone proteins for efficient packing.
cell membrane
controls the movement of substances in and out of the cell.
nucleolus
a very dense chunk of DNA responsible for the manufacture of ribosomes.
symbiosis theory
one type of prokaryote started living inside another, hence why mitochondria are the same size and shape as bacteria and have a double membrane. Mitochondria are also sensitive to antibiotics, and reproduce like bacteria, as well as having their own plasmid DNA ribosomes the same size as bacteria.
What are the structures in a mitochondria?
- cristae (folds that increase the surface area of the inner membrane)
- inner membrane (studded with stalked particles)
- outer membrane
- ribosomes (contained inside the matrix, for protein synthesis)
- loops of plasmid DNA (for protein synthesis)
- intermembrane space (low pH because contains few H+ ions)
- stalked particles (ATP synthase)
- matrix (inside of inner membrane, high pH because it contains many H+ ions)
what are the structures in a chloroplast?
- outer membrane
- inner membrane
- lamella (bridges between granum)
- stroma (space in the middle)
- granum (stack of thylakoids)
- thylakoids (membrane containing chlorophyl)
- ribosomes
- starch grain
What kind of microscope is most useful in viewing organelles?
- light micoroscope have limited effective magnification because they have a low resolution.
- transmission electron microscopes allow the user to view clear images of the inside of a cell
- scanning electron microscopes only allow the user to see the outside of a cell because the electrons fired at the sample bounce off the outside.
How are glycoproteins such as mucin adapted for their role in the golgi?
- the gene coding for the mucus protein is copied int he nucleus
- the mRNA copy of the mucin gene moves out of nucleus through the nuclear pore
- the mRNA is transported to a ribosome on the rough ER
- the ribosome uses the information on the mRNA to assemble amino acids in the correct sequence for the mucin protein
- the long chain of amino acids (polypeptide chain) is folded in the endoplasmic reticulum to form the mucin protein
- transport vesicles move the mucin protein from the ER to the golgi apparatus
- the mucin protein is slowly moved through the compartments of the golgi apparatus where the carbohydrate chains are attached.
- transport vesicles containing the finished mucin glyco-protein bud from the far end of the golgi apparatus
- the transport vesicles move along the micro tubules of the cytoskeleton to the cell surface membrane
- the membrane of the transport vesicle fuses with the cell surface membrane and the mucus is secreted from the cell.
