Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biol112 > Week 3 > Flashcards

Week 3 Flashcards

(53 cards)

Start Studying
1
Q

What makes up the cytoskeleton ?

A

Actin microfilaments, intermediate filaments , micro tubules

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

Microfilaments :
What is the structure ?
Diameter ?
Main functions ?

A

2 intertwined strands of actin, each a polymer of actin subunits
7nm
Maintenance of cell shape, changes in cell shape, muscle contraction , cytoplasmic streaming , cell motility , cell division

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

What are cellular extensions driven by ?

A

Actin polymerization

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

what do myosin molecules use to derive their energy to “walk” along actin filaments ?

A

ATP hydrolysis

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

What does the toxin Phalloidin do ?

A

Binds to F-actin preventing disassembly

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

What is the network of actin filaments just below the cell surface called ? What is its role ?

A

The cell cortex
It supports the plasma membrane and facilitates cell movement

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

What is the structure of micro tubules ?
Diameter ?
Protein subunit ?
main functions ?

A

Hollow tubes, wall consists of 13 columns of tubulin molecules
25nm with 15nm lumen
Tubulin , dimmer consisting of a-tubulin and b-tubulin
Maintenance of cell shape , cell motility ( cilia and flagella ) , chromosome movement in cell division , organelle movements

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

What happens when ATP is added to flagella and cilia ?

A

Bending of the flagella , causes motion

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

Which microtubule motors pull chromosomes ?

A

Kinetochores

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

What does ALS affect ? ( amyotrophic lateral sclerosis )

A

Affects nerve cells and spinal cord, affects movements and electrical signals due to alterations to nerve filaments

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

What happens with Epidermolysis Bullosa Simplex?

A

Defect in keratin 14 gene, skin peels at slight touch

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

What is the structure of intermediate filaments ?
Diameter ?
Subunits ?
Main function ?

A

Fibrous proteins supercoiled into thicker cables
8-12 nm
One of several different proteins depending on cell type
Maintenance of cell shape ( tension bearing elements ) , anchorage of nucleus and certain other organelles
Formation of nuclear lamina

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

What’s the difference between G actin and F actin ?

A

G actin is monomeric whereas F actin is the polymeric form that is involved in providing ell support and maintaining cell structure

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

What holds together the 2 lobes of the actin monomer ?

A

ATP

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

How is actin polymerization involved in fertilisation ?

A

The acrosome reaction in echinoderm sperm requires actin polymerization

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

What are the functions of microtubules ?

A

Maintenance of cell shape
Cell motility
Chromosome movement
Organelle movements

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

What does the drug taxol do ?

A

It is a cancer drug , it is used for ovarian cancer , breast cancer and lung cancer which prevents microtubules disassembly and therefore cell division in cancer cells.

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

What is the structure within each microtubule?

A

A core of axonemal microtubules ensheathed in an extension of the plasma membrane
9 doublets arranged in a ring , with 2 central ones connected by radial spokes 9 + 2 arrangement

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

What are doublets connected with in cilia and flagella ? What is its role ? What is the role of the cross links ?

A

Dynein protein which contracts at the expense of ATP forcing the doublets to move relative to each other
The cross links prevent the doublets sliding past each other so that the cilia or flagella bend

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

What are some differences between prokaryotic and eukaryotic flagella ?

A

Prokaryotic flagella are proton driven but eukaryotic flagella are ATP driven
Prokaryotic - rotary movement eukaryotic - bending movement

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

What do kinesin and dynein motor proteins transport along microtubules at the expense of ATP ?

A

They transport membrane bound vesicles , proteins and organelles along microtubules at the expense of ATP

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

What end do kinesins move the cargo ? What about dyneins ?

23
Q

What are the 2 main types of microtubules ?

Study These Flashcards
A

Cytoplasmic - more dynamic and loosely organised found in the cytoplasm
Axonemal - highly organised and stable found in cilia flagella and basal bodies

24
Q

What are impermeable junctions ?

Study These Flashcards
A

Tight junctions

25
What are adhesive junctions ?
Adherens junction and adhesive desmosome
26
What are communicating junctions ?
Passage of small molecules between cells. Gap junctions or chemical synapses
27
What are the functions of tight junctions ?
Fence Function: Separate the apical plasma membrane from the basal plasma membrane, thus allowing them to have different compositions. This also gives rise to cellular polarity. Barrier/gate Function: Prevent molecules from leaking between adjacent cells.
28
What is the importance of tight junctions in the stomach ?
Tight junctions keep the apical membrane components separate from the basal membrane components , in the gut this stops acid being pumped into the bloodstream
29
What are 4 types of tight junction proteins and an example of an affecting protein?
Claudins - Clostrodium difficile Occludin - vibrio cholerae JAM-A - reovirus ZO-1 - Rotavirus
30
What is the main junction protein for adherens junction ?
E-Cadherin
31
What do hemi-desmosomes connect ?
The cell base to the basal lamina
32
Where are gap junctions very abundant ?
Cardiac tissue and muscle tissue
33
Why do unicellular organisms need to divide?
To reproduce
34
Why do multicellular organisms have to divide ?
Growth and cell replacement
35
What are the phases of the cell cycle ?
G1 (growth phase ) S ( synthesis phase ) G2 ( growth phase ) Mitosis Cytokinesis
36
What happens in the G2 phase of interphase ?
-intact nuclear envelope -chromosomes replicated -centrosome replicated -microtubules extend radially forming asters
37
What are the phases of prophase ?
1. Chromatin fibres condense - forming discrete chromosomes 2. Nucleoli disappear 3. Centrosomes move away from each other 4. Mitotic spindle begins to form
38
What are the stages of prometaphase ?
1. Breakdown of nuclear envelope 2. Some microtubules attach to chromosomes at their kinetochores 3. Other microtubules interact with those from opposite poles
39
Stages of metaphase ?
Centrosomes at opposite poles Chromosomes align on the metaphase plate Sister kinetochores attached to microtubules coming from opposites poles
40
What are the stages of anaphase ?
Begins with separation of centromeres Sister chromatids move towards opposite poles of the cell Each chromatid becomes a new chromosome Poles move further apart
41
What are the stages of telophase ?
Elongation of cell by polar microtubules Daughter nucleoli begin to form at poles of cell Nuclear envelopes form Chromatin begins to decondense
42
During telophase what is also happening ?
Cleavage furrow ( protein complex ) forming Cytoplasm splits (cytokinesis )
43
What does the mitotic spindle consist of ?
Tubules Centrosomes Chromatid pairs
44
What are the 3 types of microtubules in the mitotic spindle ?
Astral Kinetochore Non-kinetochore/polar
45
What is the function of the mitotic spindle ?
To organise chromatids along the metaphase plate and then pull sister chromatids apart
46
How do astral motors work ( dynein ) ?
pull astral microtubules towards poles during prophase microtubules de-polymerise and shorten hold astral microtubules in place during metaphase and later
47
What is the role of the kinetochore motors ?
attach chromosomes to microtubules pull on microtubules during anaphase - chromosomes move towards centrosomes microtubules de-polymerise and get shorter
48
What is the role of non-kinetochore motors ?
motors are attached to a microtubule from either side where the polar microtubules overlap motors push the microtubules away in opposite directions during metaphase and anaphase microtubules polymerise and get longer cell elongates
49
What is the pulling force in chromosomal pulling?
Dynein kinetochore motors pull chromosomes towards the centrosome/pole. astral motors pull centrosomes toward inner face of the plasma membrane Both shorten depolymerise microtubules
50
What is the pushing force in separation of chromosomes ?
Kinesin non-kinetochore/polar motors add subunits (polymerises) microtubules to drive the poles of the spindle apart. This elongates the cell to aid telophase/cytokinesis
51
Describe the physical separation of chromosome pairs in anaphase ?
1. Proteins holding sister chromatids together are inactivated 2. Chromatids separate 3. Kinetochore microtubules have motor proteins (dynein) which ‘walk’ a chromosome to the nearest pole 4. Microtubules shorten by depolymerisation at their kinetochore ends Non-kinetochore microtubules elongate whole cell during anaphase Motor proteins (kinesin) attach to microtubules and lengthen them by addition of subunits
52
Describe cytokinesis in animal cells
Microfilaments form a ring at the furrow 2. Ring contracts - owing to interaction between actin and myosin filaments 3. furrow deepens until cell is pinched in two
53
Describe cytokinesis in plant cells
1. Cell plate forms at equatorial plane of the cell 2. Cell wall forms - from plate contents

Biol112 (4 decks)

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