Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

cell structure and function mid term 1 > Mid term 2 part 2 > Flashcards

Mid term 2 part 2 Flashcards

1
Q

what is the cytoskeleton

A

network of protein filaments that extends though out the cytoplasm

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

what cells have a cytoskeleton

A

eukaryotic cells

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

three types of cytoskeletal components

A

intermediate filaments, microtubules, thin filaments

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

what is the function of the cytoskeleton

A

all three cytoskeleton components: thin filaments, microtubules and intermediate filaments are involved in the formation and maintenance of cell shape and internal organization

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

Structure of intermediate filaments

A

middle size of the cytoskeleton, about 12nm in diameter, made of thousands of protein subunits that assemble into threads, they have great tensile strength

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

size of microtubules

A

largest in size of cytoskeleton about 25nm

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

size of actin filaments

A

smallest unit of cytoskeleton about 7nm

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

what is the function of intermediate filaments

A

provides mechanical strength to areas of the cell

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

what is the function of microtubules

A

provide movement of organelles, vesicles or form appendages to propel motile cells

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

what is the function of actin filament

A

provide movement, motile force for crawling cells and cell shape changes

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

where are microfilaments located

A

form a network though out the cytoplasm of most cells, they are anchored to the plasma membrane of cell cell junctions, they also form the nuclear lamina

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

terminal on the intermediate filaments

A

have a globular n terminal head and C terminal globular tail with an extended alpha helical region connecting the two. Two of the coiled coiled dimers then associate though non covalent bonding to form a tetramer

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

example of function of intermediate filaments

A

intermediate filaments are along the axons of neurons to provide internal reinforcement

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

what cells are intermediate filaments abundant

A

epithelial cells such as the skin

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

what are desmosomes

A

spot welds between adjacent epithelial cells, a desmosome is composed of a protein that extends across the membrane and also interacts with the intermediate filaments of the cytoskeleton of the cell

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

what is primary function of desmosomes

A

cell adhesion

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

4 types of IFs

A

keratin type one and two, vimetin and vimetin related filaments, neurofilaments and nuclear lamins

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

what IFs are cytoplasmic

A

kertains type one and two, vimentin and vimentin related, and neurofilaments

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

what IFs are nuclear

A

nuclear lamins

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

type one and two keratin filaments

A

type one are in epithelial cells, type two are in hair, nails and scales

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

vimetin and vimetin related filaments

A

in connective tissue cells, muscle cells and supporting cells (glial) cells of nervous system

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

nuclear lamins

A

under the nuclear envelope

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

neurofilaments

A

in nerve cells, strengthen axons and regulate nerve impulse speeds and change axon diameter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

connection of keratin filaments

A

most abundant and diverse, they span the cell and are anchored to desmosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
epidermolysis bullosa simplex
autosomal dominant mutations in keratin gene that interferes with the formation of keratin filaments in epidermis which makes skin vulnerable to mechanical injury
26
nuclear lamins
intermediate filaments in the inner surface of the nuclear membrane its a dense fibrillar network of IFs organized into lamins organized as 2D mesh
27
lamins during cell division
they can disassemble and ressemble at cell division, they dissasemble when the nuclear envelope breaks down during mitosis and reforms in each daughter cell
28
how is the assembling and disassembling of lamins done
controlled by phosphorylation and dephosphorylation of lamins by protein kinases
29
phosphorylation of lamins
dissassembly
30
dephosphorylation of lamins
assembly
31
progeria and lamins
defects in nuclear lamin are associated with certain types of progeria which causes premature aging and may impair cell division for tissue repair, mutation in gene on chromosome 1
32
function of nuclear lamina
to strengthen the nuclear envelope and participates in chromatin organization and it anchors the nuclear pore complexes embedded in the nuclear envelope
33
structure micotubules
long stiff hollow tubes that can ripidly assemble and disassemble
34
what are microtubules built from
tubulin subunits
35
types of tubulin
alpha and beta, they are similar globular proteins which form dimers and stack together by non covalent bonding to form protofilaments making the wall of the hollow cylindrical microtubule
36
what is each microtube made of
13 parallel proto filaments with alternating alpha beta tublin
37
polarity of protofilaments
each proto filament has a structural polarity alpha at one end beta at the other, the polarity is the same for all the protofilaments giving structural polarity to the microtubule as a whole
38
where does the minus end of the microtubule come from
the centrosome in a center called the microtubule organizing center and the plus end extends outward to other parts of the cell cytoplasm
39
what are centosomes made of
two centrioles that are aligned perpendicular to each other in the cell cytoplasm
40
what are centrioles made of
cylindrical array of 9 sets of microtubule triplets
41
what end of the microtubule is attached to the centrosome
negative end and the plus end goes toward cell surface
42
what is the centrosome close to when not in mitosis
the nucelus
43
what does each centrosome contain
a pair of centrioles surrounded by a matrix of proteins
44
what is the protein component that is contained in the centrosomes
gamma tubulin that forms a ring shape structure embedded in the matrix and each gamma tubulin ring serves as the starting point or nucleation site for the growth of one microtubule
45
why do microtubules need nucleating sites
it is much harder to start assembly of a new microtubule from scratch than add dimers to a preexisting structure like gamma rings
46
Tracks of microtubules
microtubules create a system of tracks within the cell along which vesicles organelles and other cell parts can move from one location of the cell to another microtubules are responsible for anchoring organelles into a specific cell location
47
example of microtubule functions in the cell
form the spindle fiber and help separate chromosomes during mitosis can form beating cilia and flagella which cause cell movement
48
dynamic instability
switching back and forth between polymerization and depolymerization: ie can grow and shrink from plus end gaining and losing subunits
49
how do microtubules grow and shrink
GTP bound to alpha and beta subunits in each free tubulin dimer when growing both alpha and beta subunits GTP bound, subunits are added to plus end of microtubules then gtp hydrolyzed to gdp in beta subunits making interaction between subunits weaker
50
GTP cap
if polymerization occurs rapidly gtp tubulin subunits keep adding to the end of the microtubule faster than GTP they carry is hydrolyzed forming GTP caps, the growing microtubule will continue to grow in that direction
51
what happens if GTP caps are lost
microtubule shrinks
52
what regulates dynamic behavior
MAPs that bind to plus end of microtubule and control growth, MAP accelerates growth by increasing incorporation of GTP bound tubulin
53
what do clasp proteins do
rescues microtubules from shrinking
54
55
capping protiens
fix microtubules to specific locations in their cell, the binding of capping proteins in their plus end prevent depolymerization
56
transport of vesicles along microtubules
in neurons all microtubules in the axon point in the same direction with plus end toward axon terminal, movement toward the end of axon terminal as well as inward towards the cell body
57
how are movement generated along microtubules
by motor proteins which use energy from ATP hydrolysis to travel along microtubules in a single direction
58
two classes of motor proteins
kinesins and dyneins
59
kinesins
move toward the plus end and away from centromere and cell body
60
dyneins
move toward minus end toward centrosome and cell body
61
structure of motor proteins
two globular ATP binding heads and a tail
62
head of motor proteins
globular Atp binding head that interacts and walks on microtubules
63
stalk of motor domains
coiled coils that hinge to provide flexibility
64
motor protein tail
binds to cell components and determine cargo type

cell structure and function mid term 1 (8 decks)

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