Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BDS1 - Human Body > Subcellular organelles and the cytoskeleton > Flashcards

Subcellular organelles and the cytoskeleton Flashcards

1
Q

describe the plasma membrane

A

-lipid bilayer with extrinsic and intrinsic proteins
-forms continuous barrier that regulates movement of molecules and ions in and out of the cell
-many membrane proteins and lipids are bound to carbohydrates to form glycoproteins and glycolipids
-membrane is fluid bc proteins and lipids can move

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is a lysosome?

A

membrane-enclosed organelle that contains many degradative enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are example of enzymes in a lysosome?

A

-nucleases
-phosphatases
-glycosidases
-proteases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are the functions of lysosomes?

A

-eliminate unwanted cellular materials and recycle their components
-destroy yeast and bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are endosomes?

A

membrane-bound vesicles formed via endocytosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is receptor-mediated endocytosis?

A

specific type of endocytosis where ligands bind to receptors on cell surface and endocytosis is triggered

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

where are the receptors in RME situated?

A

in coated pits on the cell membrane - surface is coated in clathrin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what happens in RME?

A

-when molecules attach to receptors, they are both taken into the cell in a clathrin coated vesicle (early endosome)
-as endosome grows, other vesicles from gb join and provide enzymes
-the endosome is now a lysosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

why is clathrin useful for an endosome?

A

-helps get its rounded shape
-helps it to bud off from membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what does RME help cells to take up?

A

large amounts of molecules that are present in low concentrations in the extracellular fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what happens to clathrin in RME?

A

recycled to cell surface in recycling endosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

why might RME be a bad thing?

A

because virus and bacteria can also gain access to the cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is a peroxisome?

A

small organelle which contains the enzyme catalase and some oxidases and it is similar in size to lysosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what do peroxisomes do?

A

-degrades fatty acids
-convert cholesterol to bile
-synthesise plasmalogens which is a component of myelin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is produced in the reactions bw peroxisomes and bile/fatty acids?

A

-hydrogen peroxide
-this is degraded by a catalase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how are peroxisomal disorders caused?

A

-mutations in peroxisomal enzymes or faults in peroxisomal assembly
-toxic long chain fatty acids accumulate bc they are not being degraded
-causes deficiency of plasmalogens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is autophagy?

A

the degradation of worn, abnormal or malfunctioning cellular components

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is microautophagy?

A

autophagosome fuses with lysosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is macroautophagy?

A

direct engulfment of material into lysosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is an autophagosome?

A

spherical structure with double membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is the keystone pathogen hypothesis?

A

certain low abundance pathogens can bring about inflammatory disease by remodelling a benign microbiota into a dysbiotic one

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is the keystone pathogen hypothesis?

A

certain low abundance pathogens can bring about inflammatory disease by remodelling a benign microbiota into a dysbiotic one

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is P. gingivalis and what does it do?

A

-pathogenic black pigmented anaerobic bacterium
-secretes gingipains which cause damage
-invades oral epithelium by hiding in autophagosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is exocytosis?

A

process of moving materials from within a cell to the exterior of the cell - is a type of active transport bc requires energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
describe basic process of exocytosis
-vesicles containing molecules are transported from within the cell to the cell membrane -vesicle membrane attached to cell membrane -vesicle fuses w membrane so contents are release outside the cell
25
what are the functions of exocytosis?
-allows cells to secrete waste substances e.g. hormones and proteins -used to rebuild the cell membrane by fusing lipids and proteins removed through endocytosis back into the membrane
26
where are exocytotic vesicles derived from?
Golgi body
27
what are extracellular vesicles?
lipid bilayer-delimited particles that are naturally released from cells
28
what are the different classes of extracellular vesicles?
exosomes and microvesicles
29
what are exosomes?
vesicles formed when multivesicular endosomes fuse with plasma membrane
30
how are exosomes formed?
-MVE bud inwards to form internal vesicles containing proteins and RNA -internal vesicles are released as exosomes when the MVE fuse with the cell membrane -MVE can also fuse w lysosome which degrades MVE contents
31
what are microvesicles?
vesicles that bud from plasma membrane
32
what is the Endoplasmic reticulum (ER)
-network of membranous tubules -make up about 10% of cell's total volume -continuous w nuclear membrane -consists of smooth ER and rough ER
33
describe smooth ER
-does not contain ribosomes -contains enzymes for -synthesising lipids -synthesising steroid hormones -metabolising toxins e.g. alcohol -stores calcium
34
describe the rough ER
-studded w ribosomes -site of synthesis of membrane proteins and secreted proteins -can modify proteins by adding carb and adding membrane anchors -passes proteins to Golgi in vesicles for further modification
35
how are ER storage diseases caused?
-by proteins being retained in the ER -usually due to mutations in aa sequence causing misfolding so proteins are not processed properly and cannot be transported from ER to Golgi
36
give examples of er storage diseases
Cystic fibrosis Diabetes insipidus
37
what is the Golgi body?
membrane-bound organelle made up of flattened stacked pouches called cisternae
38
what are the functions of the Golgi body?
-packaging proteins and lipids into vesicles so they can be delivered to target destination -distributed modified proteins to lysosomes, plasma membrane or secretory vesicles
39
what are the three compartments of the GB?
-cis - nearest to ER, facing nucleus -medial - middle layer -trans - furthest from ER, facing plasma membrane
40
how are the cisternae of GB held together?
matrix proteins and whole GB is supported by microtubules
41
how do vesicles from an organelle know where to go?
coated in specific proteins depending on their destination
42
how do proteins travel from ER to cis face of GB?
in COPII coated vesicles
43
what do proteins travel in from GB to plasma membrane?
clathrin coated vesicle
44
how is cholera caused?
-cholera toxin binds to component of COPI and is processed and activated in ER -cholera toxin activates CFTR channel which disrupts Cl- transport in gut -this causes secretion of water, massive diarrhoea and fatal dehydration
45
what is a mitochondrion?
membrane bound organelle that has primary function of generating ATP during oxidative phosphorylation
46
what are secondary functions of mitochondria?
-stores calcium for cell signalling -generates heat -mediate cell growth and death
47
which cells are likely to have a lot of mitochondria and which are likely to have few mitochondria?
-red blood cells have none -liver cells and muscle cells likely to have many
48
does mitochondria contain DNA?
yes
49
what is in the matrix of the mitochondria?
enzymes needed in Kreb's Cycle
50
why are mitochondrial mutations common?
because mitochondria mutate quickly in some tissue
51
what are mitochondrial disease symptoms caused by?
lack of ATP in affected organs esp organs w high energy demands e.g. muscles, CNS, heart
52
what is mitophagy?
autophagy of mitochondria
53
what diseases can mitophagy contribute to the development of?
-Parkinson's disease -dementia -also involved in switch in metabolism in cancer cells e.g. oral cancer
54
what is organelle biogenesis?
creation of cellular organelles in cells by the expansion of existing ones
55
describe the process of organelle biogenesis
The new phospholipids required for this synthesised in smooth ER Newly formed lipids ‘flip’ from inner to outer surface Move to organelles: - in vesicles (Golgi, lysosomes) - using transport proteins (mitochondria) Proteins synthesised in ER or mitochondria
56
what does the cytoskeleton do?
-Network of protein polymers within cells -dictates shape and structure of cells
57
what are the 3 polymers in cytoskeleton? (A.I.M)
-actin filaments -intermediate filaments -microtubules
58
what are cilia and flagella?
-motile structures extending from plasma membrane -present in multicellular and unicellular organisms
59
what are tubules made of in cytoskeleton
Tubules, composed of tubulin, move and position organelles
60
what are Filaments made of in cytoskeleton
Filaments, composed of actin, form a skeleton and interact with tubulin
61
what is the cytoskeleton composed of
It is composed of tubules and filaments
62
what are the functions of cytoskeleton?
-mechanical support for cell -shape and organisation -cell movement -organelle movement
63
describe prokaryotes
-no membrane bound organelles -have nucleoid -have a peptidoglycan cell wall as well as a cell membrane -aerobic bacteria have no mitochondria but generate ATP across cell membrane
64
define cytoskeleton
Network of protein fibers that help the cell maintain its shape and allow it to move
65
Describe actin filaments
-narrow flexible filaments -concentrated just below cell membrane -present in projections e.g. villi form microvilli, lamellipodia and filopodia -involved in contraction and cytokinesis -found in eukaryotic cells
66
describe actin polymerisation
-G (globular) actin is the monomer which joins together to make F (filamentous) actin -G actin goes through nucleation which requires ATP and divalent cations to form F actin through elongation -actin filaments are polarised -actin can form bundles by cross linking
67
describe the actin-myosin interaction
-myosin proteins are actin based molecular motors -use ATP to generate force along actin filaments -change shape depending on if its bound to ADP or ATP -used for muscle power, cell contraction, migration and vesicle transport
68
describe phalloidin
-toxin that targets cytoskeletal proteins -binds to F actin and prevents depolymerisation so actin cannot assemble and disassemble -used in cell imaging
69
describe cytochalasin
-fungal -blocks actin polymerisation -blocks bacterial invasion -blocks endocytosis
70
describe intermediate filaments
-rope like structures so provide mechanical strength -widely distributed -nuclear and cytoplasmic meshwork -high tensile strength -important for tissue structure and function
71
what are examples of intermediate filaments?
-veimentin -keratin -desmin -neurofilaments -lamin
72
describe keratins
-most common intermediate filament -heteropolymer of type I and type II proteins -pairing of type I and type II is tissue specific bc will have diff functions -pairing predictive of epithelial proliferative and differentiation status
73
where can keratin be found?
-skin -hair -nails
74
What is immunohistochemistry?
antibody based staining technique
75
describe the process of immunohistochemistry
-add primary antibody to tissue section which binds to antigen -add secondary antibody which binds to primary antibody -add enzyme linked to secondary antibody which converts substrate to coloured product
76
what are the effects of keratin mutations?
-cell tissue fragility bc keratin does not provide strength -blisters caused when keratin and connective tissue separate
77
what are microtubules?
hollow cylinder polymers of tubulin heterodimers
78
describe the structure of microtubules
-long and straight -one end is attached to centromere -dynamic and polarised
79
what do microtubules do?
provides structural support to cell bc it can resist compression
80
what is the mitotic spindle made up of?
microtubules and microtubule dependent motors
81
what are cilia?
tiny hair-like projections used to move a cell or to move things past a cell
82
what are cilia made of?
long bundles of the microtubule (axoneme)
83
describe the interaction of actin and microtubules
-microtubules and actin work together in cell migration and mitosis -microtubules direct actin assembly and force generation -they can be bound together by linker proteins -indirect signalling
84
name the different cell junctions
-gap junction -tight junction -desmosome -hemidesmosome -actin-linked cell-matrix junction
85
how does paclitaxel/taxol work?
binds and stabilises microtubules to prevent mitosis - used for breast and ovarian cancer
86
how does colchicine work?
causes microtubule disruption and block migration of white blood cells which decreases inflammation - used for gout and oral ulcers
87
what are tight junctions?
seals gap between epithelial cells
88
what are adherens junctions?
connects actin filament bundle in one cell with that in the next cell
89
what are desmosome?
connects intermediate filaments in one cell to those in the next cell
90
what is a gap junction?
allows the passage of small water-soluble molecules from cell to cell
91
what is a hemidesmosome
anchors intermediate filaments in a cell to ECM
92
what is an actin-linked cell-matrix junction?
anchors actin filaments in cell to ECM

BDS1 - Human Body (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions