Microanatomy

Name 3 functions of the cytoskeleton in the cell.

1. Cell structure

2. Organelle movement and vesicle movement

3. Cell motility

Function of microtubules.
Organelle position & intracelluar transport are a function of which cytoskeleton structure?
Function of intermediate filaments
Mechainical strength is a property of which cytoskeletal structure?
Function of microfilaments.
Cell shape & movement are determined by which cytoskeleton structure?
Which cytoskeletal structure can survive cell death (very strong)?
Intermediate filaments.
Which cytoskeletal structure makes up hair, nails, claws, fur, scales, and other out covering of skin?
Intermediate filaments
Desmosomes link cells together by what means?
Linking Intermediate filaments
How are cells held together?
Intermediate filaments linking to desmosomes.
How can pathologists characterize the origin of a tumor cell that may have metastasized?
Through the identification of intermediate filament type.
What does it mean if a cell is keratinized?
The cell is dead and contains a tough protein called KERATIN.
You biopsy a tumor found in the lymph node under the armpit and find that tumor cells express neurofilaments. Where was the origin of the tumor?
The brain or spinal cord.
Name the 6 types of intermediate filaments. If possible also affiliate cell types & examples.
1. Keratins
2. Vimentin
3. Desmin
4. Gilial fibrillary
5. Neurofilaments
6. Lamins
Where might you find cells with more than one nucleus?
Skeletal muscle cells, they have fused together.
Describe how chromosomes are structurally made up.
DNA wrapped around HISTONES making NUCLEOSOMES which collectively make up CHROMATIN. This makes up chromosomes.
What is the basic unit of DNA packing?
Nucleosome
What makes up a nucleosome?
DNA wrapped around HISTONES H2A, H2B, H3, & H4.
There are approximately __________ nuclear pores in a nucleus.
2000-4000
What are the 3 types of RNA transcribed from DNA?
rRNA, tRNA, mRNA
What is the name for a highly condensed, trascriptionally INACTIVE part of DNA?
Heterochromatin
What is the name for an uncondensed, trascriptionally active part of DNA?
Euchromatin
Where are rRNA, tRNA, and mRNA trascribed?
tRNA and rRNA are transcribed from euchromatin scattered throughout the nucleus. mRNA is transcribed in the NUCLEOLUS.
Where are ribosomes synthesized?
In the nucleolus.
Where are ribosomal proteins made?
In the cytoplasm, they are imported to the nucelous during ribosomal synthesis.
True or false: The large and small subunit are synthesized in the nucleolus and remain associated from then on.
False: The small and large subunits separate after being constructed together and leave separately from the nucleus.
Knobs on chromosomes indicate what?
Knobs indicate the position of genes that code for RNA.
What indicates genes that code for RNA?
Knobs; like on chromosomes 13, 14, 15, 21, and 22
Explain NLS
Nuclear Localization Sequence, signals for nuclear import and usually contains basics amino acids.
Explain NES
Nuclear Export Sequence, singals for nuclear export and contains hydrophobic amino acids usually.
Name two nuclear carriers.
Importin & Exportin
Name the enzyme that regulates nuclear carriers by binding and releasing thier cargo.
Ran – Ras-related Nuclear protein
How many ribosomes are made per minute in a single cell?
7000 ribosomes
Name the process that is highly associated with mRNA export.
Splicing
What does the Greek term -ome mean?
mass
What does the Greek term -oma mean?
body
Name two ways a cell can produce ATP.
1. Oxidative phosphorylation (in the mitochondria)
2. glycolysis in the cytoplasm
How many APTs come from the mitochondrial breakdown of a molecule of glucose?
36 ATP
What organelles can break down fatty acids to produce acetyl-Coa?
Mitochondria & Peroxisomes
What organelles can use acetyl-CoA to produce ATP?
Mitochondria
Human cells have how many mitochondria per cell?
1,000 (100-10,000)
True or False: Mitochondria are rigid structures.
False, they are very plastic and change shape rapidly
Are mitochondria spherical, tubular, or none of the above?
Tubular
What are the foldings in a mitochondria called?
cristae
Where are the only ion pores in human cells found?
Mitochondria, they are called porins
What compartment of the mitochondria has a similar contents as the cells cytosol?
The intermembrane space
How many genes are on the mitochondrial DNA?
37
How does the mitochondria make its proteins?
Most are encoded by the nuclear genome, translated on cytoplasmic ribosomes, and imported post-translationally into mitochondria.
In which compartment of the mitochondria does the DNA reside?
The matrix
How many copies of DNA are in the mitochondria?
2-10 copies
When does the mitochondria replicate for cell division?
It dynamically divides by fission and fuses as needed.
All mitochondria comes from our mother, but if sperm are packed with mitochondria to work the flagellum why don’t we get any from our father?
2 ways: (1) sperm mitochondria are tagged with ubiquitin which taggs them for destruction in the embryo. (2) dilution factor: many more mitochondria in the egg than the sperm.
Where is cytochrome C located?
It is mobile in the intermembrane space.
What is the name of a “double” phopholipid?
Cardiolipin, it has 4 fatty acid tails.
What is the key feature cardiolipin plays in the mitochondria?
It packs tighter in the inner membrane making it stronger to withstand the extreme stress from the proton motive force.
How and where is cardiolipin converted?
The mitochondria imports lipids and performs the conversion.
How is the signal for ubiquination identified?
It is buried deep in the protein structure, when the structure degrades it is exposed.
Name 3 special properties of the lysosome membrane:
1. ATP drivin [H+] pump
2. glycoprotein coat to protect itself
3. transporter channels to move out broken down products.
Name the membrane bound organelle that digest proteins.
Lysosome, proteosome also digest protein specifically but is not membrane bound.
Name the sources of vesicles that contain material bound for lysosomal degradation.
1. Endosomes containing EC molecules
2. Phagosomes, phagocytosed material
3. Autosomes containing expired organelles
Give an example of a lysosomal storage disease.
Tay-Sachs
What is the main function of the peroxisome?
To ride the body of toxins. (hydrogen peroxide, alcohol)
What two organelles are the highest oxygen consumers?
Mitochondria & Peroxisome.
Name the peroxisomal matrix enzyme that uses H2O2 to oxidize other substrates.
Catalase
Describe the B-oxidation reactants and products.
The alkyl chains of fatty acids are shortened to for Acetyl CoA, this is then used in the mitochondria if completed in peroxisomes.
Which organelle is responsible for the synthesis of bile acids from cholesterol made in the smooth ER?
Peroxisomes
What defects cause someone to have the genetic disease, Zellweger’s syndrome?
Defective PTS (Peroxisomal targeting signal) which makes ’empty’ peroxisomes. Peroxisomes make precursors to myelin, so there are neuron complications as well.
Categories: Microbiology