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Flashcards in Oragnelles II Deck (23):
1

Peroxisome

- Membrane bound
- Generates hydrogen peroxide
- performs B-oxidation of long chain fatty acids

2

Peroxisomal Fission

- Different from prokaryote division
- gets larger and larger and splits into two daughter peroxisomes

3

Evidence for Porkaryote Origin of Mitochondria

1. Contains its own small circular chromosome of DNA
2. Originates by fission from pre existing mitochondria
3. Double Membrane- host membrane and symbiotic prokaryote
4. Closest relative is Rickettsia bacteria

4

Proton Pump

- facilitates the synthesis of ATP
- H+ ions cause the rotor to spin. Mechanical energy is converted to chemical energy in the form of synthesis of ATP.
- H+ ions are then pumped back into intermembrane space

5

Melanosomes

membrane bound cytoplasmic inclusions.
- contain melanin
- gives rise to pigmentation of the skin

6

Lipfuscin

Membrane bound cytoplasmic Inclusions
- Lipid containing residues of lysosomal digestion
- residual body (tertiary lysosome)

7

Glycogen

non membrane bound cytoplasmic inclusions
- stores of glucose

8

Lipid

non membrane bound cytoplasmic inclusions
- triglycerides in storage form

9

Microfilaments

- Actin Filaments- globular monomers that assemble in the presence of K and Mg into a double stranded filamentous actin

10

Actin

Functions
- Intracellular movement and muscle contraction by forming stress fibers
- Membrane structures like microvilli and stereocilia
- locomotion (filopodia)

11

Microtubules

- wider than actin
- Heterodimer of alpha and beta subunits.

12

Microtubule Fibers

- individual microtubules
- mitotic spindle of dividing cells
- axons of neurons

13

axoneme

- doublet of microtubules
- core of cilia and the sperm tail

14

centriole

- organization of microtubules into triplets.
- 2 centrioles constitute a centrosome.

15

basal Body

a centriole that nucleates the axoneme of cilia

16

Motile Cilia

Contain a central doublet of microtubules

17

Primary cilia

Lack a central doublet of microtubules.
- nonmotile
- used for sensory function

18

Keratin

Intermediate Filament
- attach to desomosmes to form a framework within the cytoplasm
- expression can be useful in grading tumor cells
- provides barrier to dehydration

19

Zonula occludens

tight junctions
- Form a band encircling the apical end of the cell
- prevent movement between the lumen and intercellular space
- facilitates polarity
- zip lock seal is formed

20

Zonula Adherens

Intermediate Junctions
- directly under tight junctions
- Anchors cells to one another

21

Cadherin proteins

mediate cell adhesion
- bind catenin to actin filaments
- this forms the terminal web that help anchor actin filaments originating from microvilli at the apical pole of epithelial cells

22

Macula Adherens

Desmosomes
- consists of transmembrane proteins, desmoglein and desmocollin that insert into a dense attachment plaque of anchoring proteins that then binds keratin

23

Gap Junctions

- pores between adjacent cells
- rapid communication between cells
- 6 connexin proteins froms a connexon
- 2 aligned connexons froms an open channel between cells