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JH. Histo exam 1 > Cell Structure Questions > Flashcards

Cell Structure Questions Flashcards

0
Q

What are the two faces of membrane upon using freeze fracture?

A

P and E. protoplasmic (on side of cytoplasm) and extracellular.

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1
Q

Tay Sachs disease is defect in what?

A

Ganglioside metabolism. Ganglioisides are glycolipids and when defective they build up in neurons and neurons die.

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2
Q

What are the types of Endocytosis?

A

pinocytosis, receptor-mediated endocytosis, and phagocytosis.

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3
Q

What is one function of clathrin?

A

it drives pinocytosis. build fluid uptake into clathrin coated endocytic vesicles.

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4
Q

what is role of dynamin?

A

it is GTPase protein that drives pinching off of vesicles in pinocytosis.

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5
Q

what is LDL?

A

low density lipoproteins. cholesterol which needs to be taken up by endocytosis –> endosome –> lysosome. otherwise have buildup of cholesterol.

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6
Q

what is example of regulated exocytosis? unregulated?

A

regulated : release of zymogen granules which package digestive enzymes. this is triggered by increased Ca 2+ levels.

unregulated: mucous secretion.

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7
Q

what are the functions of the SER?

A

the smooth endo reticul.

  1. membrane synthesis
  2. steroid hormone synthesis
  3. detox of lipid soluble drugs, metabolic waste and ingested toxins by cytochrome P450 system which deoxid. toxins.
  4. Ca 2+ homeostasis.
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8
Q

what is the size of ribosomes? units?

A

12 nm wide x 25 nm long. consist of small 40s and large 60s subunits. they translate mRNA>

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9
Q

what is the function of the Golgi apparatus? what are thte different parts?

A
  1. post-trans modif. of proteins.
  2. assembly of multisubunit proteins
  3. protein sorting and packaging into secretory vesicles.

parts:
cis forming face, medial intermediate face, trans exit face.

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10
Q

what is the ERGIC?

A

it is the “pre-Golgi that follows the TER (transitional ER) and then comes before the CIS part of the Golgi.

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11
Q

how large are lysosomes?

A

< 1 μm. has acid hydrolases.

primary lysosome + late endosome => secondary lysosome.

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12
Q

what is lipofuscin?

A

it is a pigment that cells may accumulate and can’t get rid of after lysosomal activity. especially impacts terminally differentiated cells.

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13
Q

The accumulation of what causes Pompe disease?

A

Glycogen due to lack of glucosidase enzyme in lysoome. affects the heart. heart needs carbs.

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14
Q

What causes Hurler disease?

A

Deficit in enzyme that causes accumulation f a dermatan sulfate which is in cartilage and bone. this affects skeletal system.

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15
Q

What causes Niemann-Pick disease?

A

the deficit of Sphingomyelinase which causes accumulationo f sphingomyelin and affects CNS Oligdendrocytes.

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16
Q

What is the function of peroxisomes?

A

Peroxisomes are smaller than lysosomes (0.2μm diam) and have CATALASE and other oxid. enzymes.

breaks down long fatty acid chains to make Acetyl CoA and hydrogen peroxide. also detoxificationn.

replicate by fission.

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17
Q

How large are mitochondria? How produce ATP? what is in the different parts of it?

A

0.5μm diam and 7μm length.
produce ATP via oxid phosphor.

matrix space::

  • enzymes of Krebs cycle.
  • Matrix granules which bind Ca 2+
  • circular DNA which make mRNA
  • mRNA, ribosomes, tRNA

Inner mitochondrial membrane
-ATP synthase protein complex
-enzymes of electron transport chain
rich in cardiolipin which is 4 fatty acid chain impermeable to proteins..

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18
Q

What are the clinical manifestations of mitochondrial cytopathies?

A

Generally you have problems in muscles and cognition, since neurons and skeletal muscle cells are terminally differentiated such that there can be no “dilution” or getting slowly rid of the defective ones.

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19
Q

What are some examples of inclusions?

A

Glycogen granules
lipid droplets
pigment granules – lipfuscin, melanin
crystalline inclusions

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20
Q

What are the two different forms of chromatin?

A

Heterochromatin - condensed, inactive.

Euchromatin - dispered, transcriptionally active.

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21
Q

What are the components of the cytoskeleton and contribution to cell function?

A
  1. Actin microfilaments. 7.5 nm diam. supports structure of cell membrane and anchors integral membrane proteins. also bundles as microvilli.
  2. Intermediate filaments. 12 nm diam. have tensile strength since anchored to cell wall bby DESMOSOMES and distributing stress forces. wrap around nucleus.
  3. Microtubules. 23 nm. highways along which vesicular movement occurs. they originate from structure called centrosome/ microtubule organizing center.
  4. Microtubules.
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22
Q

Which cytoskeletal component has actin?

A

Microfilaments. they maintain cell shape and motility.

23
Q

which cytoskeletal component is involved in muscle contraction and with what other molecule?

A

microfilaments which have actin work together with myosin.

24
Q

which cytoskeletal component is responsible for cleavage furrow formation in cell division?

A

microfilaments.

25
Q

What does fascin and fimbrin do?

A

they bundle actin filaments for microvilli.

26
Q

what do spectrin, filamin, adductin do?

A

they cross-link act filaments. for actin cortex in RBC.

27
Q

what does gelsonin do?

A

it severs actin filaments for rearranging.

28
Q

what does tropomodulin do?

A

it is a protein that caps actin and prevents it from dissociation.

29
Q

What are some main functions of intermediate filaments?

A

provide tensile strength for cell shape.
ANCHOR nucleus and other organelles.
form nuclear lamina.

30
Q

What are cytokeratins?

A

they form intermediate filaments in epithelial cells. CLASS 1.

31
Q

what is vimentin?

A

forms intermediate filament in mesenchymal-origin cells like endothelial, myofibroblast, smooth muscle. CLASS II.

32
Q

what is desmin?

A

type of IF found in muscle cells.

33
Q

What is Glial fibrillary acidic protein? (GFAP)

A

IFs found in Glial cells.

34
Q

what cytoskeletal component is responsible for chromosome movement in cell division with the mitotic spindle?

A

the microtubules form the mitotic spindle.

35
Q

what is the supporting structure of cilia and flagella?

A

microtubules.

36
Q

which cytoskeletal component is responsible for resisting compression of cells to maintain shape?

A

microtubules.

37
Q

How do microtubules play a role in organelle movements?

A

Kinesin and dynein which are both ATPases are like motors that move from one end to another (kinesin is anterograde so from - to + end and dynein is retrograde so from + to - end).

38
Q

What is the structure of microtubules?

A

long, straight, rigid cylinders formed by polymerization of α/β tubulin dimers.

the - end is embedded in microtubule organizing center.
polymerization and depolymerization BOTH occur at + end.

39
Q

what are the layers in surface specialization, i.e. in lumen of small intestine?

A

the apical (facing lumen) has microvilli under which are the zonula occludens, zonula adherens, and demosome (macula adherens). then under that is the lateral and then the basal walls.

40
Q

what is the size of microvilli?

A

about 1-2μm long, 80 nm diam.

41
Q

what do cilia do in the human trachea?

A

they move along the mucous over the surface of the epithelium

42
Q

What are the ciliary axoneme?

A

longitudinal microtubules arranged in a 9+2 organization.
anchored to basal body.
motile -> dynein dependent hydrolysis of ATP. DYNEIN arms allow interaction with adjacent microtubules.
move fluids over cell surface

43
Q

What causes Kartegener’s Syndrome?

A

mutation in ciliary dynein. so dynein arms are missing or sparse. respiratory problems since no movement of mucous so piles at bottom of lungs.

44
Q

What are stereocilia?

A

not really cilia. they are long microvilli present only on cells of epididymis and hair cells of cochlear.

45
Q

what are kinocilia.

A

non-motile cilia with 9+0 axoneme. present on hair cells in inner ear.

46
Q

What is the zonula occludens?

A

Tight junctions. complex of proteins including OCCLUDIN and CLAUDIN. which fuse cell membranes together.
prevents passage of water-soluble molecules between cells.
prevents movement of integral membrane proteins. from one side of cell to other.

47
Q

What are the anchoring junctions?

A

HYDROPHILIC adhesive interactions between cells.

  • adherens junctions? - Ca 2+ dependent adhesive interactions mediated by cadherin proteins. actin filaments are anchored by interaxn with CATENIN and VINCULIN.
  • desmosomes. – adhesive interaxn mediated by DEMOGLEIN and DEMOPLAKIN. intermediate filemanted anchored to demoplakin/pakoglobin attachment plaque.
48
Q

which junctions are associated with cadherin proteins?

A

adherens junctions. hydrophobic.

49
Q

which filaments are anchored by interaction with catenin and vinculin?

A

actin filamnets in adherens junctions.

50
Q

what kind of filmanets are anchored to desmoplakin/pakoglobin attachment plaque?

A

intermediate filaments.

51
Q

what are gap junctions?

A

channels formed by aligning connexons in adjacent cell membranes. connexon = 6 connexin subunits.

allows passage of ions and small moelcules between cells.

couples cells ELECTRICALLY and METABOLICALLY.

52
Q

what are the major components of basement membrane and cell-to-extracellular matrix connections?

A

laminin, type IV collagen, entactin, perlecan.

53
Q

What is Pemphigus?

A

autoimmune disease that kills off desmosome and hemidesmosome. causes dpiermal blistering and loss of extracellular fluids.

54
Q

what is Alport’s Syndrome?

A

Inherited defect in structure of Type IV collage - so then you get hematuria - blood in urine leaking.

JH. Histo exam 1 (2 decks)

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