CYTOLOGY Flashcards
Define Cytoplasm
aqueous medium in which various organelles are suspended
What do nuclei contain?
DNA
define endocytosis
(out –> in) uptake of material through the plasma membrane
define exocytosis
(in –> out) removal of material thorugh the plasma membrane
What are the 2 types of endocytosis
- Pinocytosis
- Receptor-mediated endocytosis
define pinocytosis
the ingestion of liquid into a cell by the budding of small vesicles from the cell membrane
define receptor-mediated endocytosis
the molecule interacts with a specific binding protein, a receptor and is then imported
What is the difference between secretion and excretion?
secretion: realease of useful products
excretion: release of waste products
What kind of charge does Eosin dye hold? What charge does it bind to?
holds negative charge. binds to positively charged proteins, i.e. acidophilic proteins (acid loving)
what color does eosin stain cellular structures?
pink/red
What kind of charge does hematoxylin dye hold? What kind of charge does it bind to?
Holds a positive charge. binds to negatively charged DNA and RNA ie. basophilic (base-loving) structures.
What color does Hematoxylin stain cellular structures?
blue/purple
Define chromatin
a complex of DNA and histones (positively charged)
Define euchromatin
What color does it stain with H&E?
Chromatin is spread out- hightly active cells. active transcription.
Stains lightly basophilic (light blue)
Define heterochromatin
What color does it stain with H&E?
Chromatin more condensed. Less active cells. Less active transcription.
Stains strongly basophilic (dark blue)
What are the two types of ribosomes?
- free polyribosomes
- ribosomes bound to RER
What color does the RER stain? Why?
Basophilic due to the presence of rRNA (very negative) bound to ribosomes
What are the 2 main functions of the RER?
- protein synthesis
- post-translational modification of newly synthesized proteins to prep them for export
Proteins that are destined for secretion/export and made on the _?
RER
Identify A, B and C
A. euchromatin
B. nucleolus
C. heterochromatin
Does the smooth ER have ribosomes?
No
What is the name of the light-stained section circles in blue? Why does it stain light?
The Negative Golgi Complex.
Less proteins, more lipids = light stain
What are the 4 main phases of mitosis?
PMAT
(Prophase, Metaphase, Anaphase, and Telophase)
What is happening during prophase of mitosis?
Chromosomes condense into pairs of sister chromatids
