final exam Flashcards
where is mitochondria located within the cell?
cytoplasm of both plant and animal cells
how are mitochondrial disease inherited?
maternally
- mitochondria transferred from oocyte
- cytoplasmic inheritance (non-mendelian inheritance)
- all offspring from affected mother will have disease
list mitochondrial disorders
- leber hereditary optic neuropathy
- kearns-sayre syndrome
- myoclonic epilepsy with ragged red fibers
what is the main function of mitochondria?
conducts krebs cycle and ETC to generate ATP via oxidative phosphorylation
where would you find chloroplasts?
plant cells
what are the three filaments of the cytoskeleton?
actin (microfilaments)
intermediate
microtubules
what makes up microtubules?
alpha and beta tubulin
what makes up actin filaments?
globular proteins that can assemble and disassemble within the cell (through polymerization and depolymerization
what makes up intermediate filaments?
bunch of different size polypeptides (fibrous protein subunits), makes a trimer and is more stable than actin and microtubules
what cells and cell structures would you find microfilaments in?
muscle fibers (skeletal muscle cell)
sarcomere (A and I band)
what is the energy source required for the polymerization of tubulin and actin?
tubulin- GTP
actin- ATP
describe the structure of cilia
- bundles of microtubules
- core=axoneme
- 9+2 pattern at axoneme
- basal body where microtubules can grow 9+0 pattern
- dynein present on 9+2 arrangement
explain Kartagener’s syndrome
- autosomal recessive disorder that affects the motor protein dynein in the individuals body.
- recurrent upper respiratory tract infections, chronic sinusitis, and infertility in males (due to the inability of the sperm to travel, situs inversus with dextrocardia
colchicine
- prevents polymerization of microtubules by binding to a tubulin dimer
- halts cell division -> anti-mitotic and anti cancer drug
vincristine and vinblastine
anti-mitotic drug used as anti-cancer cells since they can preferentially kill rapidly dividing cells found in cancer
- affects microtubules
taxol
- prevents depolymerization of microtubules by increasing polymerization by depleting cytoplasmic pool of tubulin
- stabilizes microtubule
- anti-mitotic
cytochalasins
- prevent polymerization of actin by binding specifically to one end of actin filament and preventing addition of more actin molecules to that end
- metabolites released by different molds
phalloidin
- death cap mushrooms
- prevents depolymerization of actin by stabilizing actin filaments
- commonly used as cytoskeletal stain
describe interphase
where the cell grows and spends the most time in to prepare itself to divide
describe G1 phase
- occurs right after mitosis
- acts a gap for cell before needing to replicate its DNA to prepare again for cell division
describe S phase
synthesizes DNA
- cell replicates its DNA in preparation for division
describe G2 phase
second gap of interphase
describe M phase
mitosis
what is G0 phase
becomes senescent during G1 phase
what is the purpose of p53?
- tumor suppressor gene
- caretaker protein “guardian of the genome”
- 50% human cancers have mutations of it
ensures DNA’s integrity is maintained - if it notices any DNA damage, arrests cell in G1/S checkpoint and activates DNA repair mechanisms
- arrests cell through CDK inhibitor p21
- if damage can’t be repaired, activates apoptosis via BAX
what is retinoblastoma?
- childhood cancer that occurs due to a mutation in the Rb gene which is located on chromosome 13
- In order to develop a cancer in this mechanism, both genes must have a loss of function.
- “familial cancer” because most children inherit one defective Rb allele from a parent who is a carrier.
- symptoms of retinoblastoma are leukocoria — which is the abnormal white appearance of the retina upon examination, loss of vision, glaucoma, or cross-eyed vision.
what is mitosis and its purpose?
cell division to create identical daughter cell
prophase
nucleoli breakdown and DNA condenses into chromosomes
prometaphase
nuclear envelopes breaks down and kinetochores attach to microtubules
metaphase
chromosomes lined up on equator of cell
anaphase
chromosomes split into chromatids that travel to opposite ends of cell
telophase
sister chromatids are separated and have arrived at opposite poles and kinetochore microtubules begin to disappear
cytokinesis
cleavage furrow along with contractile rings causes cell to separate into two identical daughter cells
define chemotaxis
directed motion of organism towards chemical signal
define adhering junctions
mechanically hold cell together typically through desmosomes (belt, spot, hemi)
define impermeable junctions
hold cells together and also make seal so molecules can’t pass in between them typically through tight junction
define communicating junctions
allow cells to communicate with each other most commonly through gap junctions and chemical synapses
what is bullous pemphigoid?
- disease characterized by blister formation causing the epithelium to detach from the basal lamina
- caused by an autoimmune attack on different protein components of the hemidesmosome
- pruritic (itchy) skin disease that is common in people over the age of 60.
- presence of bullous pemphigoid blisters can be a side effect of certain drugs like furosemide (Lasix) which is a loop diuretic or Vildagliptin, an antidiabetic drug
What are the fibers and proteins that make up the extracellular matrix?
fibroblasts
collagen
glycosaminoglycans
elastin
what is osteogenesis imperfecta type I?
- caused by a mutation in either of the type I collagen genes: COL1A1 and COL1A2
- long bone fractures in their childhood which occur after minor trauma, mistaken for abuse
- possibility of hearing loss, and will have blue sclera
what is marfan syndrome?
- autosomal dominant disorder that is caused by a mutation in the fibrillin-1 (FBN1) gene on chromosome 16.
- long limbs, arachnodactyly, pectus excavatum, lens dislocation, aortic aneurysm, and abnormal formation of the rib cage.
merocrine secretion
cell secretes signal without damage to itself
- sweat and mammary glands
holocrine secretion
whole cell expelled during secretion and ruptured cell becomes part of secretory product
- sebaceous glands
apocrine secretion
only apical part of cell shed in secretory product
- sweat glands in armpit
