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
Q

describe basic process of exocytosis

A

-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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what are the functions of exocytosis?

A

-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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

where are exocytotic vesicles derived from?

A

Golgi body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what are extracellular vesicles?

A

lipid bilayer-delimited particles that are naturally released from cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what are the different classes of extracellular vesicles?

A

exosomes and microvesicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what are exosomes?

A

vesicles formed when multivesicular endosomes fuse with plasma membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

how are exosomes formed?

A

-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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what are microvesicles?

A

vesicles that bud from plasma membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what is the Endoplasmic reticulum (ER)

A

-network of membranous tubules
-make up about 10% of cell’s total volume
-continuous w nuclear membrane
-consists of smooth ER and rough ER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

describe smooth ER

A

-does not contain ribosomes
-contains enzymes for
-synthesising lipids
-synthesising steroid hormones
-metabolising toxins e.g. alcohol
-stores calcium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

describe the rough ER

A

-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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

how are ER storage diseases caused?

A

-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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

give examples of er storage diseases

A

Cystic fibrosis
Diabetes insipidus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

what is the Golgi body?

A

membrane-bound organelle made up of flattened stacked pouches called cisternae

38
Q

what are the functions of the Golgi body?

A

-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
Q

what are the three compartments of the GB?

A

-cis - nearest to ER, facing nucleus
-medial - middle layer
-trans - furthest from ER, facing plasma membrane

40
Q

how are the cisternae of GB held together?

A

matrix proteins and whole GB is supported by microtubules

41
Q

how do vesicles from an organelle know where to go?

A

coated in specific proteins depending on their destination

42
Q

how do proteins travel from ER to cis face of GB?

A

in COPII coated vesicles

43
Q

what do proteins travel in from GB to plasma membrane?

A

clathrin coated vesicle

44
Q

how is cholera caused?

A

-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
Q

what is a mitochondrion?

A

membrane bound organelle that has primary function of generating ATP during oxidative phosphorylation

46
Q

what are secondary functions of mitochondria?

A

-stores calcium for cell signalling
-generates heat
-mediate cell growth and death

47
Q

which cells are likely to have a lot of mitochondria and which are likely to have few mitochondria?

A

-red blood cells have none
-liver cells and muscle cells likely to have many

48
Q

does mitochondria contain DNA?

A

yes

49
Q

what is in the matrix of the mitochondria?

A

enzymes needed in Kreb’s Cycle

50
Q

why are mitochondrial mutations common?

A

because mitochondria mutate quickly in some tissue

51
Q

what are mitochondrial disease symptoms caused by?

A

lack of ATP in affected organs esp organs w high energy demands e.g. muscles, CNS, heart

52
Q

what is mitophagy?

A

autophagy of mitochondria

53
Q

what diseases can mitophagy contribute to the development of?

A

-Parkinson’s disease
-dementia
-also involved in switch in metabolism in cancer cells e.g. oral cancer

54
Q

what is organelle biogenesis?

A

creation of cellular organelles in cells by the expansion of existing ones

55
Q

describe the process of organelle biogenesis

A

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
Q

what does the cytoskeleton do?

A

-Network of protein polymers within cells
-dictates shape and structure of cells

57
Q

what are the 3 polymers in cytoskeleton? (A.I.M)

A

-actin filaments
-intermediate filaments
-microtubules

58
Q

what are cilia and flagella?

A

-motile structures extending from plasma membrane
-present in multicellular and unicellular organisms

59
Q

what are tubules made of in cytoskeleton

A

Tubules, composed of tubulin, move and position organelles

60
Q

what are Filaments made of in cytoskeleton

A

Filaments, composed of actin, form a skeleton and interact with tubulin

61
Q

what is the cytoskeleton composed of

A

It is composed of tubules and filaments

62
Q

what are the functions of cytoskeleton?

A

-mechanical support for cell
-shape and organisation
-cell movement
-organelle movement

63
Q

describe prokaryotes

A

-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
Q

define cytoskeleton

A

Network of protein fibers that help the cell maintain its shape and allow it to move

65
Q

Describe actin filaments

A

-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
Q

describe actin polymerisation

A

-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
Q

describe the actin-myosin interaction

A

-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
Q

describe phalloidin

A

-toxin that targets cytoskeletal proteins
-binds to F actin and prevents depolymerisation so actin cannot assemble and disassemble
-used in cell imaging

69
Q

describe cytochalasin

A

-fungal
-blocks actin polymerisation
-blocks bacterial invasion
-blocks endocytosis

70
Q

describe intermediate filaments

A

-rope like structures so provide mechanical strength
-widely distributed
-nuclear and cytoplasmic meshwork
-high tensile strength
-important for tissue structure and function

71
Q

what are examples of intermediate filaments?

A

-veimentin
-keratin
-desmin
-neurofilaments
-lamin

72
Q

describe keratins

A

-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
Q

where can keratin be found?

A

-skin
-hair
-nails

74
Q

What is immunohistochemistry?

A

antibody based staining technique

75
Q

describe the process of immunohistochemistry

A

-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
Q

what are the effects of keratin mutations?

A

-cell tissue fragility bc keratin does not provide strength
-blisters caused when keratin and connective tissue separate

77
Q

what are microtubules?

A

hollow cylinder polymers of tubulin heterodimers

78
Q

describe the structure of microtubules

A

-long and straight
-one end is attached to centromere
-dynamic and polarised

79
Q

what do microtubules do?

A

provides structural support to cell bc it can resist compression

80
Q

what is the mitotic spindle made up of?

A

microtubules and microtubule dependent motors

81
Q

what are cilia?

A

tiny hair-like projections used to move a cell or to move things past a cell

82
Q

what are cilia made of?

A

long bundles of the microtubule (axoneme)

83
Q

describe the interaction of actin and microtubules

A

-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
Q

name the different cell junctions

A

-gap junction
-tight junction
-desmosome
-hemidesmosome
-actin-linked cell-matrix junction

85
Q

how does paclitaxel/taxol work?

A

binds and stabilises microtubules to prevent mitosis - used for breast and ovarian cancer

86
Q

how does colchicine work?

A

causes microtubule disruption and block migration of white blood cells which decreases inflammation - used for gout and oral ulcers

87
Q

what are tight junctions?

A

seals gap between epithelial cells

88
Q

what are adherens junctions?

A

connects actin filament bundle in one cell with that in the next cell

89
Q

what are desmosome?

A

connects intermediate filaments in one cell to those in the next cell

90
Q

what is a gap junction?

A

allows the passage of small water-soluble molecules from cell to cell

91
Q

what is a hemidesmosome

A

anchors intermediate filaments in a cell to ECM

92
Q

what is an actin-linked cell-matrix junction?

A

anchors actin filaments in cell to ECM

BDS1 - Human Body (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions