Cell Organelles Flashcards

1
Q

What are the 2 main regions of the cell?

A

cytoplasm + nucleus = protoplasm

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2
Q

What is cytoplasm?

A

jelly like substance that constitutents float in

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3
Q

What are the contents of cytoplasm?

A

organnelles and inclusions

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4
Q

Cytoplasmic ground substance is known as?

A

cytoplasmic matrix

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5
Q

What is an organelle?

A

little organ - memmbrane systems + membrane bound compartments + nonmembranous structural components

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6
Q

What are inclusions?

A

materials that may of may not have a membrane

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7
Q

What are microcompartments and what happens in them?

A

spaces enclosed by membranes in which substrates & products of chemical reactions are segregated or concentrated

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8
Q

What are the membrane bound organelles?

A

plasma membrane, RER, SER, golgi apparatus, mitochondria, lysomes, endosomes, perioxisomes

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9
Q

The roles of the intramembrane system?

A

provide surface area for chemical reactions

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10
Q

What is the cell membrane made of?

A

phospholipid bilayer + glycoproteins + cholesterols

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11
Q

How are phospholipids amphiphatic?

A

they have both hydrophilic (phosphate head) and hydrophobic components (fatty acid tail)

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12
Q

What is the cell coat made of?

A

glycocalyx - glycolipids + glycoproteins

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13
Q

What is a cell membrane?

A

mosaic of protein molecules in a fluid bilayer of phospholipids - it is not static

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14
Q

Function of cholesterol?

A

maintaining fluidity in high and low temps.

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15
Q

Cholesterol function at high temperatures?

A

at high temps. phospholipids move away from each other making the membrane leaky so cholesterol keeps the phospholipids together

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16
Q

Cholesterol function at low temperatures?

A

at low temps. phospholipids pack so closely together making the membrane brittle so cholesterol packs in bettween the phospholipids enhancing fluididty

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17
Q

What enhances fluidity?

A

unsaturated hydrcarbon tails prevent molecules from packing closely together enhancing fluidity

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18
Q

What are functions of membrane proteins? TESCA

A
  1. transportaion of substances - ions channels, carriers 2. enzymatic activity 3. signal transduction 4. cell to cell recognition - receptors 5. adhesion - attachment to the cytoskeleton and extracellular matrix
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19
Q

How do substances pass through the cell membrane?

A
  1. diffusion 2. active transport 3. vesicular transport
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20
Q

What is vesicular transportation?

A

formation of vesicles from membrane or fusion of vesicles with membrane

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21
Q

What is endocytosis?

A

vesicular transport of substances entering the cell

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22
Q

What is exocytosis?

A

vesicular transport of substances leaving the cell

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23
Q

What are the forms of endocytosis?

A

phagocytosis, pinocytosis and facilitated endocytosis

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24
Q

What is the function of the cell membrane?

A

organization and localization of function - compartmentization

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25
What is the endoplasmic reticulum?
a series of interconnected membrane bound flattened sacs called cisternae - has large flattened sheets
26
What is cisternae?
flattened sacs that are interconnected and membrane bound
27
What is present in the RER?
ribosomes - for protein synthesis
28
What is the RER continuous with?
nuclear envelope
29
What are polysomes/polyribosomes?
groups of ribosomes attached to mRNA
30
What is the function of polysomes?
protein synthesis - 1. integral membrane proteins 2. cell proteins 3. proteins for export
31
Free ribosomes synthesize proteins to be used?
within the cell
32
What are the 3 functions of RER?
1. protein biosynthesis 2. initial protein processing 3. quality control 4. form transition vesicles
33
Explain RER initial protein processing?
1. initial glycosylation 2. polypeptide folding 3. assembly of multi-subunit proteins
34
What do transition vesicles do?
shuttle lipids and proteins to golgi apparatus
35
What is the smooth endoplasmic reticulum?
network of membranous sacs, vesicles and tubules continuous with the RER but lacking ribosomes
36
Cells with a lot of SER show what under a light microscope?
acidophilia - may look empty
37
Sacroplasmic reticulum stores what in muscles?
calcium ions
38
What is hydroxylation?
addition of hydroxyl groups to organic acceptor molecules - increases solubility of hydrophobic drugs in water
39
What are the functions of the smooth ER?
1. lipid absorption 2. glycogen metabolism 3. membrane formation & recycling - phospholipids 4. detoxify drugs and other noxious substances (hydroxylation)
40
Where is SER found abundantly?
liver cells - sight of detoxification of drugs and other substances
41
What is the golgi apparatus?
enveloped, disc shaped, slightly curved vesicle system with two sides - system of membranes parallel to each other
42
Does the golgi apparatus stain with H & E?
No
43
What are the faces of the golgi apparatus?
1. forming face/ cis-Golgi 2. maturing face/ trans-Golgi
44
Which side receives transport vesicles from the RER?
forming face/Golgi A
45
What are 3 kinds of proteins that coat vesicles?
1. clathrin 2. COPI 3. COPII
46
What are 7 functions of the Golgi Apparatus?
handles distribution of newly synthesized membranes and their proteins - 1. packaging and shipping 2. modifying glycoproteins and hormone precursors received from the RER 3. sorting of proteins according to their target sequence or attached oligosaccharides 4. recycling of plasma membrane proteins via endocytosis 5. ER-specific protein retrieval through tags e.g. KDEL (Lys-Asp-Glu-Leu) 6. synthesis of lysosomes and their loading of enzymes 7. synthesize polysaccharide and emulsify lipid
47
Explain the SNARE hypothesis?
hypothesis connects coated vesicles and target membranes : SNARE protein - SNAP receptor
48
What are SNARE proteins?
the molecular componnts that facilitate sorting and targeting of vesicles - v-SNARES and t-SNARES
49
Discuss vesicular trafficking proteins?
SNARE proteins - v-SNARES and t-SNARES allow a vesicle to recognize a target organelle
50
What are mitochondria?
powerhouse of the cell
51
What is the structure of mitochondria?
1. outer membrane 2. folded inner membrane - folds are known as cristae 3. matrix
52
Mitochondria is present in all cells but?
red blood cells
53
What are the TEM configurations of mitochondria?
1. orthodox 2. condensed
54
Describe the orthodox configuration?
the cristae is prominent, matrix compartment large and has a low level of oxidative phosphorylation
55
Describe the condensed configuration?
cristae not easily recognizable, matrix concentrated and reduced and has a high level of oxidative phosphorylation
56
Mitochondria is crucial in?
apoptosis - cytoskeletal disintegration, metabolic derangement, genomic fragmentation
57
What are lysomes?
suicide bags with hydrolytic enzymes - isolate digestive enzymes from the rest of the cell
58
What are the functions of the lysosomes?
intracellular digestion
59
What are primary lysosomes?
newly formed lysosomes - not yet acquired the materials to be digested
60
What are secondary lysosomes?
formed by the fusion of the primary lysosome with the substrate to be degraded and have contents in the various stages of degradation 1. phagosomes/heterophagic - substances are of extracellular origin 2. autophagic - with materials of intracellular origin
61
What are tertairy lysosomes?
debris filled vacuole or broken down contents of sec. lysome
62
What are endosomes?
vesicles formed as a result of phagocytosis - receive lysosomal enzymes from clathrin coated transported vesicles
63
Endosomes are subclassified into?
early and late endosomes depending on their stage of maturation
64
Pathway followed by endosomes?
1. it may fuse with lysosome to form phagosome 2. it may fuse with another domain or region of cell membrane to release its product from cell (transcytosis)
65
Late endosomes mature to form?
lysosomes - have inactive enzymes
66
Function of endosomes?
intracellular sorting and transport systems
67
Function of early endosomes?
1. internalize materials from outside the cell via plasma membrane invagination 2. recycle receptors and transport them back to the cell surface membrane 3. can receive vesicles from the golgi apparatus and send them back
68
Function of late endosomes?
fuse with lysosomes and thereby allows for lysosomal degradation of endosomal content
69
What are peroxisomes?
spherical organelles surrounded by a single membrane
70
Function of peroxisomes?
1. degradation of hydrogen peroxide 2. beta oxidation of very long chain fatty acids - starts in the peroxisome and proceeds until carbon chain has been reduced to a length 10 carbons 3. phospholipid exchange 4. bile acid and cholesterol synthesis
71
Name the oxidative enzyme in peroxisomes?
catalase
72
Where are peroxisomes found?
liver and kidney cells