Cell Structure 2 Flashcards
What are some functions of the RER?
- Synthesis of integral membrane and secreted proteins
2. Initial site of post translational modification of proteins/lipids.
What are some functions of the SER?
- Membrane synthesis
- Steroid hormone synthesis
- Detoxification (lipid soluble drugs, metabolic wastes, ingested toxins) using cytochrome p450 system.
- Ca2+ homeostasis (sarcoplasmic reticulum)
How small is a ribosome? Can you use a light microscope to see it?
12 nm wide, 25 nm long. No, light microscope resolution = .25 microns.
T or F. Secreted/transmembrane proteins often have a signal sequence, which helps move translation to the RER.
True. The hydrophobic signal sequence is translated, which halts translation until it reaches the RER, where translation resumes.
What are some functions of the Golgi apparatus?
- Further post translational modifications of proteins (additional sugars, phosphorylated, sulfated etc).
- Assembly of multisubunit proteins
- Sorting and packaging into secretory vesicles.
Which face (cis, medial, trans) is closer to the plasma membrane? To the ER?
- Trans
2. Cis
Label the following in order (Golgi stuff). Medial, ERGIC, Trans, TGN, Cis.
ERGIC, Cis, Medial, Trans, TGN.
(ERGIC = endoplasmic reticulum Golgi Intermediate Compartment)
(TGN = Trans Golgi Network)
What is a lysosome?
Small vesicles filled with acid hydrolases.
Where are lysosomes derived from?
Trans Golgi Network (TGN).
Membranes of the trans Golgi Network contain ______________ receptors that bind lysosomal enzymes.
mannose 6 phosphate receptors.
Listed are 6 types of substrates. Name the corresponding enzyme that breaks them down.
- Proteins
- Nucleic acids
- Polysaccharides
- Organic linked sulfates
- Lipids
- Organic linked phosphates
- Proteases
- Nucleases
- Glycosidases
- Aryly sulfatases
- Lipases/phospholipases
- Phosphatases
Give an example of why a cell would want to go through autophagy?
Get rid of damaged organelle.
Since epithelial cells don’t have an endocytotic pathway, they cannot remove ________.
lipofuscin residual bodies.
Tay Sachs is a deficit of the (1)_______ enzyme. (2)_________ accumulates as a result. (3)________ is most affected by Tay Sachs.
- Hexosaminidase
- Gangliosides
- CNS neurons
Hurler is a deficit of the (1)_______ enzyme. (2)_________ accumulates as a result. (3)________ is most affected Hurler.
- L-Iduronidase
- Dermatan sulfate
- Skeletal system
Niemann Pick is a deficit of the (1)_______ enzyme. (2)_________ accumulates as a result. (3)________ is most affected by Niemann Pick.
- Sphingomyelinase
- Sphingomyelin
- CNS Oligodendrocytes
Pompe is a deficit of the (1)_______ enzyme. (2)_________ accumulates as a result. (3)________ is most affected by Pompe.
- Glucosidase
- Glycogen
- Heart
Peroxisomes contain _______.
Catalase and other oxidative enzymes.
2 functions of peroxisomes include ______.
- Break down of long fatty acid chains to produce Acetyl CoA and hydrogen peroxide.
- Detoxification
How does a peroxisome replicate?
Fission. Enzymes are synthesized in the cytoplasm.
How small is a peroxisome?
0.2 microns.
How big is a mitochodria (diameter, length)?
0.5 microns in diameter, up to 7 microns in length.
What is the function of mitochondria?
Produces ATP via oxidative phosphorylation. Houses ETC enzymes and ATP synthase protein complex.
The matrix space of mitochondria houses ____, ____. ____, ____.
- Enzymes of Kreb cycle.
- Matrix granules (Ca homestasis)
- Circular DNA
- mRNA, tRNA, ribosomes
T or F. Individuals are mosaics of genetically distinct mitochondria.
True.
Is inheritance of mitochondria paternal or maternal?
Maternal.
What is a clinical manifestation of mitochondrial cytopathies?
increased lactic acid levels.
Name 4 examples of inclusions.
- Glycogen granules
- Lipid droplets
- Pigment granules (lipofuscin, melanin)
- Crystalline inclusions
What is the difference between heterochromatin and euchromatin?
Heterochromatin is condensed, inactive and often on the edges of the nucleus. Euchromatin is dispersed, transcriptionally active and not on the edges of the nucleus.
What does the nucleolus do?
Site of RNA synthesis, and assembly of ribosomal subunits.
What is the most basophilic structure in the cell?
Nucleolus
Euchromatin has a diameter less than ______ (approximately).
30 nm.
What does the nuclear pore complex transport?
- Free passage of ions/molecules <60kDa
- Facilitates bidirectional active transport of larger molecules (importins, exportins on molecules help transport in and out of nucleus).
