BIOCHEMISTRY- Cellular Flashcards
Who controls the checkpoints between each transition phase of cell cycle?
Cyclins
Cyclin dependent Kinases
Tumor suppresors
Which phase is the shortest in the cell cycle?
Mitosis
What phases does Mitosis includes?
Profase, Metaphase, anaphase and telophase
Which phases are of variable duration?
G1 and G0
During the Regulation of cell cycle, they constitutive and inactive
CDKs
Are consider regulatory proteins that control cell cycle events; phase specific
Cyclins
In the regulation of cell cycle, this regulatory proteins activate CDKs
Cyclins
True or false… is a requirement that the Cyclin -CDK complexes must be both activated and inactivated for the cell cycle to progress
True
Two examples of Tumor suppressors
p53 and hypophosphorylated RB
What does p53 and hypophosphorylated RB normally do to the cell cycle phases?
inhibit G1 to S progression
What happens if there is a mutation for p53 and hypophosphorylated RB genes?
Results in unrestrained cell division
Which syndrome is characterized by a unrestrained cell division caused by a mutation for p53 and hypophosphorylated RB?
Li-Fraumeni syndrome
What happens during the G phase of the cell cycle?
Gap or Growth
What happens during the S phase of the cell cycle?
Synthesis
This kind of cell types remain in G0, regenerate from stem cells
Permanent
Examples of permanent cells
Neurons, skeletal and cardiac muscle, RBCs
This is the main characteristic for the stable cells
They enter G1 from G0 when stimulated
Another name for the stable cells
quiescent cells
Which ones are example of stable cells?
Hepatocytes, lymphocytes
This cells never go to G0, divide rapidly with short G1
Labile cells
Give example of cells that are most affected by chemotherapy
Bone marrow, gut epithelium, skin, hair follicles, germ cells
Bone marrow, gut epithelium, skin, hair follicles, germ cells… are examples of cells that never go to G0, divide rapidly with short G1, which kind of cells are they?
Labile cells
In the cell, it´s the synthesis site of secretory proteins and of N-linked oligosaccharide adition to many proteins
Rough endoplasmic reticulum
It´s the name given to RER in neurons, they sinthesize peptide neurotransmitters for secretion
Nissl bodies
Which is the function for the free ribosoms?
Site of synthesis of cytosolic and organellar proteins
Which kind of cells are rich in RER
Mucus secreting goblet cells of small intestine and antibody-secreting plasma cells
Where is the site of steroid synthesis and detoxification of drugs and poisons in the cell?
Smooth endoplasmic reticulum
This kind of cells are rich in SER
Liver hepatocytes and steroid hormone-producing cells of the adrenal cortex and gonads
Is consider the distribution center for proteins and lipids from the ER to the vesicles and plasma membrane.
Golgi apparatus
Who modifies N-oligosaccharides on asparagine?
Golgi apparatus
What does the Golgi apparatus adds on serine and threonine?
O-oligosaccharides
In the cell trafficking, what does the Golgi apparatus adds to proteins for trafficking to lysosomes?
Manosse–phosphate
What is the function for the endosome?
They´re sorting centers for material, sending it to lysosomes for destruction or back to the membrane/Golgi for further use
Where do the endosome are localized?
Outside the cell or from the Golgi
What kind of disorder is the I-cell disease (inclusion cell disease)?
Inherited lysosomal storage disorder
Which is the defect in th I-cell disease?
Defect in phosphotranferase
What happens to the Golgi if there is a defect in the phosphotransferase?
Failure of the Golgi to phosphorylate manose resideus on glycoproteins
So… if there is a failure of the Golgi to phosphorylate manose resideus on glycoproteins in the I-cell disease, what happens to the proteins?
Proteins are secreted extracellularly rather than delivered to lysosomal enzymes
Knowing all the pathophysiolgy of the I-cell disease, what are clinical findings?
Coarse facial features, clouded corneas, restricted joint movement, and high plasma levels of lysosomal enzymes
What is the prognosis for the childhood in the I-cell disease?
Fatal
If there is an absent or dysfunctional
Signal recognition particle (SRP), what happens to the proteins in the cytosol?
The proteins accumulate in the cytosol
In the vesicular trafficking proteins, what is the COPI?
It´s a retrograde movement of proteins
What is consider a retrograde movement of proteins in the cell?
Golgi→Golgi;
Golgi→Endoplasmic reticulum
What is the COPII, In the vesicular trafficking proteins?
An anterograde movement of proteins
What is consider an anterograde movement of proteins in the cell?
Golgi→Golgi;
Endoplasmic reticulum→Golgi
Trans Golgi→Lysosomes;
plasma membrane→endosomes
This are a kind of vesicular trafficking proteins
Clathrin
Is the LDL receptor activity an example of receptor mediated endocytosis?
True
What is the composition of the peroxisome?
membrane-enclosed organelle
They´re involved in the catabolism of very-long-chain fatty acids and amino acids
Peroxisome
It´s a barrel-shapped protein complex that degrades damaged or ubiquitin-tagged proteins
Peroxisome
Which disease is implicated in ubiquitin-protesome system defects?
Some cases of Parkinson disease
Which is the structure of the microtubule?
Cyclindrical structure composed of a helical array of polymerized heterodimers
In the microtubules, which are the heterodimers that we can find?
Alfa and Beta Tubulin
Which kind of bound does each dimer has?
2 GTP bound
Where do the microtubules are incorporated?
into Flagella, cilia, mitotic spindles
How do you consider the structur of the microtubules?
Grow slowly, Collapses quickly
How do the microtubules and the neurons are related?
they are involved in slow axoplasmic transport
Which Drugs act on the microtubules?
Microtubules Get Constructed Very Poorly Mebendazole Griseofulvin Colchicine Vincristine/Vinblastine Paclitaxel
Which kind of filament do the Microtubules have?
Protofilaments
This are the two types of molecular motor proteins for the microtubules
Dynein and Kinesin
Which kind of movement does the the Dynein has in the microtubules?
retrograde
Which direction is the retrograde movement of the dynein?
+ → -
Manages the anterograde movement in the microtubules
Kinesin
It has this direction in the microtubule - → +
Kinesin
Which kind of arrangement does the cilia structure has?
9+2 arrangement of microtubules
In the cilia this structure links peripheral microtubules and causes bending of cilium by diferential sliding doublets
Axonemal dynein-ATPase
How many microtubules does the cilia has peripheral?
9 doublets
How many microtubules does the cilia has centrally?
Two
Which syndrome is characterized by ciliary dyskinesia?
Kartagener syndrome
Who in the cilia structure is responsable for the Kartagener Syndrome?
immotile cilia due to a dynein arm defect
Which manifestations do we see in the reproductive aspect in the Kartagener syndrome?
Male and female infertility due to immotile sperm and dysfunctional fallopian tube cilia
What risk do the pregnant women has in the ciliary dyskinesia?
Ectopic Pregnancy
This are other manifestations of the Kartagener syndrome or ciliary dyskinesia
Bronchiectases, recurrent sinusitis and situs inversus
What is the importance of Actin and myosin?
Muscle contraction, microvilli, cytokineses, adherens junctions
Long and structural polymers…Who is it actin or myosin?
Actin
Which form does the myosins have?
dimeric
ATP-driven motor proteins that move along actins
Myosins
They´re responsable of the movement, found in the cilia, flagella, mitotic spindle, axonal trafficking and centrioles
Microtubule
They provide structure. Found in Vimentin, desmin, cytokeratin lamins, glial fibrillary acid proteins (GFAP) and neurofilaments
Intermediate filaments
Which is the composition of the plasma membrane?
Asymetric lipid bilayer
In the structurally composition of the plasma membrane, what does it contains?
Cholesterol, phospholipids, sphingolipids, glycolipids and proteins
What does the Fungal membranes contain?
Ergosterol
In the immunohistochemical stains for intermediate filaments, where do we find Vimentin?
Connective tissue
In the immunohistochemical stains for intermediate filaments, we find this in the muscle?
Desmin
In the immunohistochemical stains for intermediate filaments, we find this in the Neuroglia?
GFAP
Where is located the ATP site in the NA+-K+ ATPase in the plasma membrane?
cytosolic side
What happens next, after each ATP is consumed in the sodium-potassium pump, ?
3 Na+ go out and 2 k+ come in
Which is the effect of the Ouabain if it binds to the Sodio potassium pump?
Inhibits by binding to K+ site
This are Cardiac glycosides that directly inhibit the Na+-K+ ATPase
Digoxin and digitoxin
After the direct inhibition of the Na+-K+ ATPase by the Cardiac glycosides, who is indirect inhibited?
Na+/ Ca2+
If the Na+/ Ca2+ is indirectly inhibited by digoxin and digitoxin, what happens to the calcium and the cardiac contractility?
Increase in calcium levels with increase contractility
Who is the most abundant protein in the human body?
Collagen
Which is the most common collagen type?
Type I
Where do we find Type I Collagen?
Found in the bone, skin, tendon, dentin fascia, cornea, late wound repair
We find this type of Collagen in Reticulin (skin, blood vessels, uterus, fetal tissue, granulation tissue)
Type III
Found in the basement membrane, basal lamina, lens
Type IV
Where do we se Type II collagen?
Cartilage (including hyaline), vitreous body, nucleus pulpose
This collagen is deficient in the uncommon vascular type of EHler-Danlos syndrome
Type III
This collagen is decreased in production in osteogenesis imperfecta type 1
Type I
Which collagen is defective in Alport syndrome?
Type IV
Which collagen is targeted by autoantibodies in Goodpasture syndrome?
Type IV
Inside the Fibroblast, where is the site where the collagen is synthesis and structure?
RER
Name the four phases that occurs inside the fibroblasts to synthesis collagen
Synthesis
Hydroxylation
Glycosylation
Exocytosis
During the collagen synthesis what is the preprocollagen?
Translation of collagen alpha chains
Which are the three main components in the collagen synthesis?
Gly-X-Y
Glycine
Proline
Lysine
From the three main components in the collagen synthesis, which one best reflects collagen synthesis, and becomes 1/3 of collagen?
Glycine
In the collagen shynthesis who´re the ones that suffer hydroxylation?
Proline an lysine residues
Which vitamin its required for the hydroxylation during the collagen shynthesis?
Vitamin C
Name of the disease when there is a Vitamin C deficiency
Scurvy
Who suffers the glycosylation during the collagen shynthesis?
Pro Alpha chain hydroxylisine residues
Who forms the triple helix of 3 collagen alpha chains after the Pro Alpha chain hydroxylisine suffers glycosylation?
Procollagen via hydrogen and disulfide bonds
During the collagen shynthesis, this happens when there is a problem forming tripla helix
Osteogenesis imperfecta
Who suffers exocytosis to the extracellular space after all the inside fibroblast collagen synthesis?
Procollagen
What are the two process that happen outside the fibroblast in order to make collagen
Proteolytic processing
Cross-linking
During the proteolytic process, What happens to procollagen in order to become tropocollagen
Cleavage of disulfide-rich terminal regions of procollagen
During the Cross linking phase in the collagen synthesis, what kind of bonds need to happen to form the collagen fibrils?
Reinforcement of many staggered tropocollagen molecules
What kind of bonds does the tropocollagen molecules have with each other to make the collagen fibrils?
Covalent lysine-hydroxylysine cross linkage (by Cu2+- containing lysyl oxidase)
Which disease has problems with the Cross-linking in the collagen synthesis
Ehlers Danlos
Which is the most common form of osteogenesis imperfecta?
Autosomal dominant
Osteogenesis imperfecta manifestations can include
Multiple fractures with minimal trauma during the birth process
Blue sclerae
Hearing loss (abnormal ossicles)
Dental imperfections due to lack of dentin
Why can we see the blue sclera in the osteogenesis imperfecta?
Due to the translucency of the connective tissue over the choroidal veins
What´s wrong in Ehlers-Danlos syndrome?
Faulty collagen synthesis
Which are the most common findings in Ehlers-Danlos?
Hyperextensible skin, tendency to bleed and hypermobile joints
How many types of Ehlers Danlos can we see?
6+ types
Which other problems can be associated with Ehlers Danlos?
Joint dislocation, berry and aortic aneurysms, organ rupture
From all the Ehlers Danlos types, which is the most common?
Hypermobility type (joint instability)
In Ehlers Danlos, Which collagen is mutated in the Classical type?
Type V collagen
In Classical type of Ehlers Danlos, which are the common symptoms?
Joint and skin symptoms
There is a Vascular type of Ehlers Danlos syndrome associated to vascular and organ rupture, which collagen is affected?
Type III collagen
It consider a connective tissue disease caused by impired copper absortion and transport
Menkes disease
What happens if the copper is affected in Menkes disease?
Leads to decrease activiy of lysyl oxidase (cooper is a necesary cofactor)
In Menkes disease, Whiche are the common findings?
Brittle, kinky hair
growth retardation
hypotonia
Stretchy protein within skin, lungs, large arteries, elastic ligaments, vocal cords, ligamenta flava
Elastin
Which are the main components for Elastin?
Rich in proline and glycine, non hydroxylated forms
Which phase gives Elastin its elastic properties
Cross-linking that takes place extacellulary
Who breaks down the elastin?
The elastase
Who normaly inhibites the elastase?
a1 antitrypsin
This syndrome is caused by a defect in fibrillin
Marfan syndrome
Which glycoprotein forms a sheath around elastin and is affected in Marfan syndrome?
Fibrillin
We know that emphysema can be cause by a antitrypsin deficiency… so who has excess activity in this disease?
Excess Elastase activity
