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HIST BIOM > cell organelles > Flashcards

cell organelles Flashcards

1
Q

Since ribosomes contain RNA they are intensely __ Where are they formed in the __

A

Basophillic nucleolus

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2
Q

Cytoplasm of a cell rich rich in ribsomes stain with

A

Basophillic dye which is hematoxylin The structures usually stained are those that contain negative charges, such as the phosphate backbone of DNA in the cell nucleus and ribosomes.

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3
Q

“Basophils” are cells that “love” the blue, and usually show up deep blue under standard staining techniques (H&E).

A

the BLUE, and usually show up deep blue under standard staining techniques (H&E).

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4
Q

Major function of proteins is to stabalize

A

The structure of RNA

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5
Q

Different Types of Ribosome

A

i. rRNA: Small and large subunit. Made of RNA and protein ii. mRNA: specifics the polypeptide sequence iii. tRNA: shuttles in amino acids into the ribosome for nascent (new) protein synthesis. Has an anticodon which is complementary to mRNA codons. Ist codon in AUG.

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6
Q

Ribosome Complex Function

A

translations of mRNA into protein (acts as RIBOZYME)

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7
Q

Polyribozymes

A

single mRNA molecules associted with a number of ribosomes along its length longer mRNA greater # of ribosomes

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8
Q

Free Ribosome ( Polysome)

A

typically synthesize cytosolic and cytoskeletal proteins and proteins for import into the nucleus, mitochondria and peroxisomes.

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9
Q

Protein synthesis continues until

A

until a stop codon is reached

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10
Q

i. Bound to Ribosome :

A

RER, typically synthesize proteins that may require further processing before incorporation into membranes, mRNA determines stored in lysosomes or eventually secreted from the cell.

may require further processing in golgi and other organelles, and many proteins will be secreted

ie glcosylation

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11
Q

What is a signal sequence and a signal recognition particle

A

Signal sequence is the INITAL part of mRNA which is a stretch of 20 to 25 hydrophobic AA Signal recognition particle SRP- recognizes and binds to the signal sequence , SRP blocks further elongation until mrna atacches to RER

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12
Q

Vectoral Discharge

A

Chanel created by protein translocators on the RER bound to ribsomes form a channel where NEW SYNTHESIZE PROTEINS PASS after this signal seq. is clipped off , Inside the RER lumen the signal peptide is removed

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13
Q

i. SRP .

A

releases the signal peptide allowing translation to continue and translocation through the ER membrane.

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14
Q

Smooth ER Functions

A
  1. Carb metabolism and breakdown of glycogen 2. Detoxify drugs 3. Regulate muscle contraction (lumen sequesters Ca2+) Synthesis of phospholipids & cholesterol
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15
Q

Plasma Membrane is a

A

lipid bilar phospholipid molecules Heads-charge polar Tails-long fatty acid chains

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16
Q

Transmembrane proteins aka INTERGRAL functions as

Peripheral Protein

A

proteins function as pores and receptors

membrane proteins act as accessory proteins– can be on the inside or outside

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17
Q

Freeze fracture

A

Crack phosolipid down the middle verticle , if you fold the top layer up thats the E face the Z face is the layer that is inside the bottom

you see and E (outer) and Z (inner) place

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18
Q

Nucleus consisit of

A
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19
Q

Nuclear Membrane Compnents

A
  1. outer: covered with free ribosomes and can be continuous with RER
  2. inner: associated w/ nuclear lamina, bind to chromatin in non divinding cells ( resting state)
  3. Between is the cisternae

Regulates flow of fluid in and out

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20
Q

Nuclear Lamina

A
  1. fibrous matrix (2D network) present immediately beneath the inner membranes of all nuclei. Made of 3 proteins: lamins A,B,C- help organize chromatin w/in nucleus -binds to specific proteins in the membrane and to specific regions of chromatin.
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21
Q

Nucleolus

A
  1. site of RNA transcription. It assembles and disassembles during the cell cycle.
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22
Q

Nuclear Envelope

A

Control flow of fluid/proteins/ions in and out of cell

Large molecules controlled by nucleoporins

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23
Q

what goes In and Out f the nucleous by what of nuclear envelop/pores

A
  1. IMPORTIN: Going in: Chromatin, ribosomal proteins, TF, enzymes
  2. EXPORTIN: Going out: ribosomal subunits & other RNA associated proteins.
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24
Q

Insinde the nucleoulus there is a nucleus organizing region, its parts are

A
  1. pars amorpha: consit of DNA sequences coding for rRNA
  2. Pars fibrosa: consist of primary rRNA transcripts.
  3. Pars granulosa: maturing ribosomal subunits.
  4. NAC: nucleolus associated chromatic

Nucleolonema- pars fibrosa and pars granulosa, but no amorpha

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25
Q

Nucleuolus assembles and disassembles during

A

Cell Cycle

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26
Q

Two types of Chromatin and their color

A
  1. Chromatin: clumps, 2 types Heterochromatin: heavy staining. Euchromatin: unwound, light staining
  2. Components: DNA, protein (histones and non-histone chromosomal prteins TFs)
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27
Q

What are the phases of mitosis? and what happens in each?

A
  1. Interphase: period of growth between mitosis. Cell carries normal functions
  2. Prophase: nucleus disappears and chromatin condenses into chromosomes. Centrosomes migrate to opposite poles from which mitotic spindles forms
  3. Metaphase: chromosomes further condense and align at the equatorial plane.
  4. Anaphase: sister chromosomes move towards spindle poles
  5. Telophase: sister chromosomes arrive at the poles.
  6. Cytokinesis: a cleavage furrow divides the cytoplasm and duplicated chromosomes into 2 daughter cells.
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28
Q

How do prokayotes and Eukaryotes divide

A

Prokaryotes ( including chrolorpast and mitochondria) divide by BINARY FISSION (CLONES)

Eukaryotes Divide by Mitosis and MEiosis ( genetic diversity)

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29
Q

In the Mitoic Cycles cells spend most time

A

Most time in G1 phase, then will divide and go to S phase = but proteins are being mad in mitosis phase

30
Q

Phases of Mitosis are:

A
31
Q

Ribosomes consist of what type of sub units

A

a small and large subunit

trna transfer AA to mrna, as template of aa is put together , nascent protein is made

32
Q

What is the movement of the polypeptide in the RER

A
33
Q

Identify RER and SER

A

RER is in the left corner notice the ribosomes on it smooth ER is where the black arrow are point no ribosomes

34
Q

Aphibians and Plants Have ALOT more DNA than Other organisms becasue

A
  1. Plants are sedientary and need more genes for photosynthesis . They need more genes for their survival because they are sedentary they need to protect them self in case of drought or poison they need more functionality
  2. AMhibians have TWO different lives initially they are aquatic then later they are land (frogs) they transform
35
Q

PRotein folding occurs in RER or SER?

What type of microscope is the ER viewed only

A

Rough ER

ELECTRON MICROSCOPE -TEM

36
Q

What part of the ER are proteins modified ?

A

LUMEN

37
Q

Faces f the GOLGI

A
  1. 2 faces: cis and trans.
    1. Cis: face associated with ER

Trans: outward facing- where mature proteins are released

38
Q

Gogli Function

What is the golgi stained with in order to see it onTEM

A

Golgi: consists of stack of membrane in the cell that modifies, sorts, and packages proteins from the endoplasmic reticulum.

  1. Imaging: silver based stain on TEM
39
Q

Translational ER

A

Specialized region immediately next to the RER , in this region vesicles (cotaining prtoeins) pinch off.

40
Q

Uncoated/Coated Vesicles /Transfer Vesicles

A
  1. COP-II: forward movement FROM RER TO GOLGI
  2. COP-I: retrograde movement. FROM GOLGI BACK TO THE ER -maybe because the protein were misfolded

These vessicles are either coated from ER=COPII:can polarize to form polygonal structure

OR

Coated from other ORganelles=COPI

ON THE THE SURFACE OF THESE VESICLES ARE v-SNARE WHICH DETERMINE WHAT THEY WILL FUSE WITH

Vesicular transport between the RERE and Golgi is regulated by COPs

  1. COP-II: forward movement FROM RER TO GOLGI
  2. COP-I: retrograde movement. FROM GOLGI BACK TO THE ER -maybe because the protein were misfolded so they want to try to correct
41
Q

IDENTIFY THIS SLIDE STUCTURES

A
42
Q

What does KDEL do

A

KDEL is a receptor that mediates retrivel of misfolded proteins from Golgi BACK to the ER

43
Q

Lysozome arrise from the

What specific residue do lysozoe contain

optimmal pH

A

Golgi

Lysozome contain a specific carbihydrate residue –Mannose-6-phosphate -M6P

COntains large number of acid hydrolase which BREAK DOWN A VARIETY OF MOLECULES – Acid hydrolases in primary lysosomes work at pH 5, but are inactive at cytosolic pH 7.2

Optimal enzymatic activity pH is 5

44
Q

Lysozomes

A

​

Purpose is to degrade substances within the cell , Lysosomes: have enzymes that are active at very acidic pH. These enzymes travel through the Golgi with M6P receptors which targets the vesicles for the lysosome.

45
Q

What are the different types of Lysozome

A
  1. Primary: just budded off Golgi and can fuse with other vesicles
  2. Secondary: digestive vacuole, multivesicular body, generalized secondary lysosome, autophagic vacuole. contain ingested substances - small fragments of digested material enters the cytoplasm and can be reused
  3. Tertiary: enzyme activity is complete-stains VERY dark àresidual body àlipofusion
46
Q

Residual bodies

Lipofuscin, their types

A

older lysosomes containing the remnants of digested material are called Residual bodies - in some cells there are large quantities of residual bodies referred to as Lipofuscin

Types

a) digesstive vacuoles (large) - resulting from the phagocytosis of large particles such as bacteria.
c) Autophagic vacuoles - containing intracellular organelles such as mitochondria.
e) Multivesicular bodies - contain numerous vesicles.
3) Endosome – Prior to fusion with lysosomes cells take up material through the process of endocytosis into an endosome\Endosomes then fuse with other vesicular organelles that takes on lysosomal enzymes.

47
Q

Answer

A

residue that is added in the Golgi –Mannose-6-phosphate -M6P

The rest are for ER

48
Q

Perioxisomes

How do they split?

A

carry out the oxidation of various substances - contains a series of enzymes that produce H202, which in turn is utilized by the enzyme Catalase to oxidize various substances - acts to detoxify substances (e.g. ethanol) and breakdown fatty acids

They split by FISSION form daughter peroxisomes ( not the binary one of prokaryote)

49
Q

What do Peroxisomal Enzymes do

A

Peroxisomal enzymes Beta-Oxidation f long fatty acid chains making them mediumm and they got to Mito ( first step of catabolism)

50
Q

Mitochondria

endosymbiotic

A
51
Q

Evidence for Endosymbiotic theory:

A
  1. Each mitochondrion contains its own small circular chromosome of DNA (just like prokaryote organisms), ribosomes, mRNA and tRNA, all similar to corresponding bacterial components.
  2. New mitochondria originate by fission (like prokaryotes) from pre-existing mitochondria (i.e. not by mitosis).
  3. Each mitochondrion has a double membrane, the outer from the ancestral host cell, the inner from the symbiotic prokaryote.
  4. BEST –The closest relatives of mitochondria (genotyping) are the rickettsia bacteria, which are modern-day intracellular parasites of eukaryotic cells.
52
Q

How is mitochondria inherited

A

It is inherited maternally, does not change DNA because divided by fission ( mitochondrial EVE, we all of same origin mito dna)

53
Q

Mitochondira Function/ Parts

A
  • powerhouse of the cell - number vary depending upon the cell type, most numerous in cells requiring large amounts of energy

Outer Membrane - contains channel-forming proteins which make the membrane permeable to small molecules - similar to the endoplasmic reticulum.

Intermembrane Space - chemically equivalent to cytosol with respect to small molecul

Inner Membrane - contains special lipids that make it relatively impermeable to ions and small molecules - highly folded to form Cristae which increase the surface area - shape and number of cristae vary depending upon the cell contains the following elements:

a) Transport proteins to make the membrane selectively permeable to certain substances (e.g. ATP).
b) Proteins of the Electron Transport System (Respiratory Chain).
c) Elementary (or F1) Particles (Fig. 16) - knob-like structures - contain ATP synthetase activity.

Matrix

54
Q
  1. ATP synthesis

How is Energy created

A

most occurs during aerobic respiration. Pyruvate + fatty acids à kreb cycle

carries out Oxidative Phosphorylation (i.e. requires 02) in which NADH produced by various metabolic reactions is converted into ATP - this is done through the Chemiosmotic Mechanism,

55
Q

What is Cyoplasmic Inclusions

A

Pigment Granules

TYPES

  1. Melanosomes: membrane enclosed granules w/melanin. Found I inner pigmented layer of non-neural retina
  2. Lipofuscin: membrane enclosed lipid containing residues of lysosomal digestionàresidual body ( tertiary lysozome
  3. Glycogen: not membrane bound: stores are a source of energy. Glycogenolysis degrades glycogen into individual molecules of glucose
  4. Lipid: not membrane bound. Triglycerides in storage form.
56
Q

Glycogen is stored in the

How is it stained?

A

Liver - stores energy

For light microscopy, glycogen can be stained using the periodic acid-Schiff reagent.

b. Under the electron microscope (after staining with lead), glycogen appears as small, electron-dense granules that have an irregular shape - they are not directly covered with a membrane

57
Q

Lipids (tryglycerides) are stored in

A

Fat

Stained with dark perimeter, look at arrow

58
Q

What are the parts of cytoskeleton

A

Microtubules- tubulin

Microfilaments-actin - smallest

Intermediates

59
Q

Microfilaments (5-7nm) (composition)

Function

A

Actin consists of globular monomers that assemble in the presence of K+ and Mg2+ into a double stranded helix of filamentous actin.

*In pic AF actinfilament is way smaller than MT

Function

  • Intracelularmovement
  • MUSCLE CONTRACTION
  • Membrane Structure( MICROVILLI and SteroCIllia)
  • Locomotion (cortical flow model)
60
Q

Actinfilaments Form

A

Form terminal web attached to zonula adherens underlying the apical cytoplasm.

61
Q

Mictrubules (25nm)

Types

A
  1. Microtubules may exist as individual fibers, grouped as doublets with other proteins in cilia or as a triplets in centrioles.
  2. Fibers:
  3. Axoneme: 9+2
  4. Centriole: organization of microtubules into triplets!
62
Q

What are the two types of cillia

A

Motile Cilia- contain central doublet

Primary cilia - LACK a central doublet of microtubles , NON-MOTILE, they have sensory function

63
Q

Microtubules Fibers

A

Fibers: observed as mitotic spindle of dividing cells also in axons of neurons

  1. Heterodimers of Alpha and beta subunits. Free dimers may polymerize to form a microtubule with a slight spiral organization and polarity ( + and – ends). Microtubules may exist as individual fibers, grouped as doublets with other proteins in cilia or as a triplets in centrioles.
64
Q

axoneme

A
  1. Axoneme: the organization of microtubules into doublets and partial doublets with other proteins to form the core of cilia (flagella) and sperm tail
65
Q

Centriole

A
  1. Centriole: organization of microtubules into triplets! Two orthogonal centrioles constitute a centrosome. Pairs of centrioles are described as microtubule organizing centers (MTOC) in mitotic cells, which nucleate the mitotic spindle.

9+0 pattern– triplets no center

66
Q

Basal Body

A
  1. Basal body: centriole that nucleated the axoneme of cilia. 9+2

Basal bodies are structures that are resemble centrioles . From the basal bodies, cilia and motile flagella grow. Unlike centrioles and basal bodies, ciliary axonemes have nine microtubule doublets and two central microtubule “spokes”.

A basal body\ is a protein structure found at the base of a eukaryotic undulipodium (cilium or flagellum). It is formed from a centriole and several additional protein structures, and is, essentially, a modified centriole.[1] Basal body serves as a nucleation site for the growth of the axonememicrotubules.

67
Q

Intermediate filament

A
  1. Characteristics: keratin filaments attached to desmosomes to form a framework w/in cytoplasm. Keratin consists of at least 30 isoforms which can vary in expression in different grades of tumor cells. Accumulation of keratin in epidermis provides a barrier to reduce dehydration in terrestrial vertebrates.
68
Q

Types of cell Junctions

A
69
Q

Zoca Occludens

what are they made off

A

TIGHT JUNCTIONS , PREVENT movement of molecules between the Lumen and intercellular space = so molecules that are crossing epithliel sheet must pass through a CELL RATHER THAN BETWEEN OR AROUND

MADE OF OCCLUDIN/CLAUDIN-trans mem. proteins

facilitates polaririty

70
Q

Zona Adherins

where are they locatedin comparion to other junctions

What does it form in the cell ?

What is it made of

A

Function is to anchor cells to each other Intermediate Junctions anchoring point for actin fillaments with actin filaments

Located RIGHT BELOW ZONA OCCLUDENS

  1. Actin filaments form the terminal web that help anchor actin filaments originating from microvilli at the apical pole of epithelial cells.

made of caderin protiens

71
Q

Desmosomes

aka

Macula Adherins

A
  1. form spot welds around cell perimeter for cells to attach to each other. Hemi-desmosomes: anchor the basal cytoplasm to the basal lamina of the Basement membrane ( basal lamina + lamina reticularis)
72
Q

Gap Junctions

Communications

A

Mediate rapid coordination of cell rapid communication

made of 6 connexin proteins

  1. Small molecules can pass through channel and mediate signal transduction for coordinated function ( like contraction).

Structure: 6 connexin proteins form a connexon.

HIST BIOM (2 decks)

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