Exam 1 – Lecture 4: Non-membranous Organelles Flashcards
What is the structure of microtubules?
Non-branching and rigid
Hollow tubes of protein polymers
What do microtubules do?
Form microtubular organizing centers (MTOC)
What do MTOCs do?
Form the basis of spindles
What do microtubules have a role in?
Intracellular transport / motion, cell shape, mitosis
What are 2 types of microtubules?
α and β tublin
What moves along micotubules?
Dyneins and kinesins
What do dyneins do?
Carry things to the cell
What do kinesins do?
Carry things away from the cell
Where is actin found?
In all cells
What is the structure of actin?
Helical array
What are the 2 types of actin?
Globular (G) and filamentous (F) actin
What do the actin associated proteins do?
Binding Severing Capping Cross-linking Motor
What are the contractile proteins in muscle?
Actin and myosin
What is the funtion of actin?
Anchor, motion, μvilli
What does anchor mean?
Attach cells to things around it
What are intermediate filaments like?
Highly variable, non-polar polymers
Cable-like structure
What do intermediate filaments do?
Cell-cell and cell-matrix interaction
What are examples of intermediate filaments
Keratins
Vimentin and vimentin-like proteins
Neurofilaments
Laminin
What does non-polar mean?
Non-directional
How does the lowest level of epithelium attach to the basement membrane?
Intermediate filaments
What are intermediate filaments very important in?
Cancer diagnostics
What is keratin prominent in?
Epithelial tissues
What is vimentin prominent in?
Connective tissues
What is the focal point for MTOC?
Centrioles
What are centrioles?
Cylindrical triplets of microtubules
Mitotic spindles
Basal bodies
What are basal bodies?
The attachment centrioles for cilia and flagella
What are inclusions?
Cytoplasmic accumulations
What are examples of cytoplasmic accumulations?
Lipofuscin Hemosiderin Glycogen Lipid droplets Crystalline
What is the yellow of a bruise?
Lipofuscin
What is glycogen?
Where glucose is stored
Why is glycogen not seen on H and E?
It is water soluble
What cannot be seen on H and E? What do they become?
Lipids
Clear spots
What are ribosomes the site of?
Protein translation
What are the 2 types of ribosomes?
40s and 60s
What are ribosomes the target of?
Many antibiotics
What are ribosomes made of?
RNA and protein
What is the nucleus envelope like?
Membrane bound
What is stored in the nucleus of eukaryotes?
Genetic information
Chromatin
What is chromatin?
DNA and protein
What is the substance in a nucleus?
Nucleoplasm
What is euchromatin?
Active, light in microscope
Not electron dense
Spread out and read DNA
What is heterochromatin?
Inactive, dark on microsope
Electron dense
Chromosomes are not very active
What are chromosomes like in the nucleus?
Discrete
Most times not visible (mitosis)
What is the nucleolus?
Site of RNA synthesis
Initial ribosomal assembly
Cell cycle control
