BIOCHEM--Cellular Flashcards
what are the cell cycle phases?
M
G1/G0
S
G2
M phase includes…
mitosis and cytokinesis
what are the parts of mitosis
prophase prometaphase metaphase anaphase telophase
What is the shortest phase of the cell cycle
M
4 components involved in regulation of the Cell Cycle
- cyclin dependent kinases
- cyclins
- cyclin-CDK complexes
- tumor suppressors
What do cyclin-CDK complexes do?
phosphorylate other proteins to coordinate cell cycle PROGRESSION
What do tumor suppressors do?
p53 induces p21, which inhibits CDK»_space;> stop progression of cycle from G1 to S
What are permanent cells?
Cells that stay in G0
regenerate from stem cells
Examples of permanent cells
neurons
skeletal and cardiac muscle
RBC
What is a stable/quiescent cell?
enters G1 from G0 when stimulated
examples of stable/quiescent cells
hepatocytes
lymphocytes
PCT
periosteal cells
what are labile cells?
never go to G0, divide rapidly with a short G1.
examples of labile cells
bone marrow gut epithelium skin hair follicules germ cells
which type of cells are most affected by chemotherapy?
labile cells
Vesicular trafficking proteins: COP I
Golgi»_space; Golgi (retrograde)
cis-Golgi»_space; ER
Vesicular trafficking proteins: COP II
ER»_space; cis-Golgi (anterograde)
Vesicular trafficking proteins: Clathrin
trans-Golgi»_space;lysosomes
plasma membrane»_space; endosomes
What is Zellweger Syndrome
AR disorder of peroxisome biogenesis
mutated PEX genes
Hypotonia, seizures, hepatomegaly, early death
What is Refsum Disease
AR disorder of alpha-oxidation, so phytanix acid not metabolized to pristanic acid
what 4 processes are peroxisomes involved in?
- beta-oxidation of very-long-chain FA
- alpha-oxidation (a strictly peroxisomal thing)
- catabolism of branched-chain FA, AA, and EtOH
- synthesis of cholesterol, bile acids, and plasmalogens
Adrenoleukodystrophy
x linked recessive
Disorder of beta-oxidation»_space; VLCFA build up in adrenals, white matter of brain, testes
What is a proteasome
a barrel-shaped protein complex that degrades damaged or ubiquitin-tagged proteins.
Defects in the ubiquitin-proteasome system have been implicated in some cases of what?
parkinson’s disease
Microfilaments:
- Function
- Examples
- muscle contractions, cytokinesis
2. actin, microvilli
Intermediate filaments:
- Function
- Examples
- maintain cell structure
2. vimentin, desmin, cytokeratin, lamin, GFAP, neurofilaments
Microtubules:
- Function
- Examples
- movement, cell division
2. cilia, flagella, mitotic spindle, axonal trafficking, centrioles
Describe the structure of a microtubule
cylindrical outer structure made of helical array of polymerized heterodimers of alpha and beta tubulin. Has a (+) and (-) end
Each tubulin dimer has ___ ___ bound.
2 GTP
Microtubules grow ___, and collapse ___.
grow slowly, collapse quickly
Molecular motor proteins travel along microtubules.
Who goes which way?
Dynein travels retrograde to microtubule (+ to -)
Kinesin travels anterograde to microtubule (- to +)
in which direction are microtubules oriented in the cell?
Negative end Near Nucleus
Positive end Points to Periphery
Most abundant protein in the human body
collagen
Collagen types and what they are found in
I: Bone, skin, tendon
II: carTWOlage
III: reticulin
IV: basement membrane
“Be (So Totally) Cool, Read Books”
Collagen is 1/3 ___
glycine
Vit C is required for ___ of proline and lysine residues in collagen.
Hydroxylation
Steps in collagen formation
- synthesis
- hydroxylation
- glycosylation
- exocytosis
- proteolytic processing
- Cross-linking
If can’t form triple helix of 3 collagen alpha-chains, you have what condition?
osteogenesis imperfecta
if you cant cleave the disulfide-rich terminal region of procollagen to create insoluble tropocollagen, what condition do you have?
Ehlers-Danlos
If you cant cross-link to make collagen fibrils, what condition do u have?
Ehlers-Danlos, or menkes disease
Osteogenesis Imperfecta: most commonly caused by which genetic defects?
COL1A1, COL1A2
Osteogenesis Imperfecta: what is the most common form of this disease?
AD with decreased production of NORMAL type 1 collagen
Osteogenesis Imperfecta: Manifestations
multiple fractures w/ minimal trauma
blue sclera
tooth abnormalities
hearing loss
Osteogenesis Imperfecta can be confused with…
child abuse
Osteogenesis Imperfecta: treatment
bisphosphonates to decrease fracture risk
Osteogenesis Imperfecta: “Patients can’t BITE” pneumonic
Bones = multiple fx
I (eye) = blue sclera
Teeth = dental imperfections
Ear = hearing loss
Ehlers-Danlos Syndrome: what is it?
faulty collagen synthesis causing hyperextensible skin, hypermobile joints, and tendency to bleed (easy bruising).
Most common type of Ehlers-Danlos Syndrome
Hypermobility type with joint instability
Ehlers-Danlos Syndrome, classical type: what mutation, and what kind of symptoms
mutation of type V collagen (COL5A1, COL5A2)
joint and skin symptoms
Ehlers-Danlos Syndrome, vascular type: mutation and symptoms
Deficient type III procollagen
fragile tissues incl vessels, muscles, organs that are prone to rupture
Menkes Disease: what is it
X linked recessive CT disease caused by impaired copper absorption and transport bc defective menkes protein»_space;> decreased activity of lysyl oxidase
Menkes Disease: Clin
Brittle “kinky” hair, growth retardation, hypotonia
Marfan Syndrome: mutated gene and inheritence
FBN1 on chr 15, AD
Marfan Syndrome: mutation leads to what?
Defective fibrillin, causing a CT disorder affecting the skeleton, heart, and eyes.
Marfan Syndrome: Clinical findings
Tall w/ long extremities pectus carinatum hyper mobile joints long tapering fingers/ toes cystic medial necrosis of aorta aortic incompetence dissecting aortic aneurysms floppy mitral valve subluxation of lenses upward and temporarily
