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Cleavage Furrow - Definition and Function

source : biologydictionary.net

Cleavage Furrow – Definition and Function

Cleavage Furrow Definition

A cleavage furrow is an indentation that appears in a cell’s surface when the cell is preparing to divide. It marks the beginning of the cell’s “pinching” its cell membrane and cytoplasm down the middle. Eventually, the cell will pinch itself completely in two, forming two daughter cells.

This furrow is created by the same proteins that allow muscle cells to contract: actin and myosin. These proteins, which have the ability to expand or contract, form a “contractile ring” that begins squeezing the cell along its middle.

The squeezing creates a drawstring effect, by this contractile ring until the opposite ends of the ring meet in the middle of the cell. At this point, the cell membrane fuses shut on either side of the contractile ring – creating the membranes of two new and independent cells.

Cleavage furrows are primarily found in animal cells and some algal cells. Plant cells, which have stiff, inflexible cell walls that cannot be easily bent or “pinched,” use a cell plate instead.

The cell plate grows a new cell wall from the middle of the cell outward to touch the edges, instead of pinching the cell membrane inward until it meets in the middle.

The graphic below shows a comparison of a cleavage furrow to a cell plate:

Function of Cleavage Furrow

Cells reproduce by splitting in two. After successful cellular reproduction, each half of the parent cell becomes a new, independent cell. This “daughter cell” can then grow and divide itself, and this “cell cycle” continues infinitely, or until the cell population becomes too dense.

Cells must undergo many steps to reproduce successfully. Within the cell, DNA and essential organelles must be copied and then equally distributed to the opposite sides of the cell’s cytoplasm that will become its two daughter cells.

Once all of its components have been copied and distributed so that two healthy daughter cells will be produced, the cell must actually divide in two.

Animal and algal cells, like most cells, have a complex network of proteins called a “cytoskeleton,” which controls the shape of the cell. The cytoskeleton includes motor proteins, such as actin and myosin, which can expand or contract to change the cell’s shape.

The cell’s cytoskeleton is called upon when a cell has to change shape. This may be required when a cell wants to form a vesicle from its cell membrane, such as to ingest or excrete a substance. It is also called upon when the cell needs to reproduce by dividing in two.

Cell cycle – The cycle by which cells divide, grow, prepare to divide, and then repeat the process to perpetuate cellular life. Cytoskeleton – A network of proteins that are responsible for the shape of a cell. Mitosis – The process by which eukaryotic cells reproduce, by splitting into two identical daughter cells.

Quiz

1. In which organism would you NOT expect to find cleavage furrows during cell division?A. A catB. Green algaeC. A daisyD. None of the above

Answer to Question #1

C is correct. Cleavage furrows are not found in plant cells, because plant cells have rigid walls that cannot be bent. Instead, plant cells grow new cell walls from the inside using a cell plate.

2. Which of the following proteins is NOT involved in the creation of the cleavage furrow?A. ActinB. DNA polymeraseC. MyosinD. None of the above

Answer to Question #2

B is correct. Actin and myosin are both involved in the tightening of the contractile ring and the creation of the cleavage furrow. DNA polymerase is not involved with this process.

3. Which of the following could be a possible consequence for a cell that produced a nonfunctional actin protein?A. The cell could not reproduce because it could not replicate its DNA.B. The cell would reproduce too quickly because its cell cycle would be accelerated.C. The cell could not reproduce because it was unable to split its cytoplasm into two daughter cells.D. None of the above.

Answer to Question #3

C is correct. A cell without functioning actin might not be able to form a cleavage furrow and ultimately split into two daughter cells.

In this electron micrograph of a cell, the cleavage furrow has nearly...

In this electron micrograph of a cell, the cleavage furrow has nearly… – cleavage furrow — a deepening constriction of the plasma membrane at the equator of a dividing cell, formed by the pinching in of the membrane as the diameter of the contractile ring decreases …cleavage furrow in Community Dictionary. The band of microfilaments during cytokinesis in mobile division that splits both daughter cells' membranes in half. Biology instructors everywhere tend to be…cleavage furrow: The invagination of the cell membrane , at the equatorial plane of the cell, that characterizes the onset of cytokinesis in animal cells .

What does cleavage furrow mean? – AZdictionary – Cleavage Furrow Definition A cleavage furrow is an indentation that appears in a cell's surface when the cell is preparing to divide. It marks the beginning of the cell's "pinching" its cell membrane and…What does cleavage-furrow mean? (biology) The invagination of the cell membrane, at the equatorial plane of the cell, that characterizes the onset of cy…Definition of Cleavage furrow in the Definitions.net dictionary. Information and translations of Cleavage furrow in the most comprehensive dictionary definitions resource on the web.

What does cleavage furrow mean? - AZdictionary

cleavage furrow – definition and meaning – While the term 'cleavage furrow' was initially associated with animal cells, such a structure occurs in many other types of cells, including unicellular protists.Cleavage furrow Definition from Encyclopedia Dictionaries & Glossaries. In cell biology, the cleavage furrow is the indentation of the cell's surface that begins the progression of cleavage, by…In cell biology, the cleavage furrow is the indentation of the cell's surface that begins the progression of cleavage, by which animal and some algal cells undergo cytokinesis, the final splitting of the…

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CellDivision_Mitosis w- Interpreter – In the eukaryotic cell cycle we go through a number of different phases – the first is
interphase this is essentially the rest and growth phase we also look at replication of the DNA only occurring in this phase – G1 is growth this is the start of the entire cycle "S" is synthesis of DNA or replication of the DNA only G2 we look at more growth if we're going to divide a cell in half — it has to
get bigger first so the cell grows and grows
and grows and then we go through mitosis or cell division mitosis is the division of the nucleus cytokinesis is division of the cytoplasm or the cell itself so in this phase that we start so this is our start point we're going to grow go through DNA synthesis or replication we are gonna grow again and then we're gonna divide so mitosis is division of the nucleus and of the cell itself as we mentioned on a 24 hour cycle which is roughly what it
takes for your cell to go through an entire
cycle of cell division or the entire cell cycle as we refer to it this whole process of division takes about 1
hour the rest takes about 23 hours depending on the cell now this might seem like a long time — it's not
particularly a long time because you have got
to remember every cell in your body that is active is going
through this every single day now when we talk to a prokaryotes — that
binary fission — only takes about 20 minutes so the complexity of the cells with growing
and orgtanelles and having to go through a lot more DNA replication and processing takes
much much much longer than we saw in the prokaryotes mitosis has six major stages that we're going to look at prophase – prometaphase – metaphase – anaphase – telophase and
cytokinesis – one of these you already know
all cytokinesis we said is cell division we are going to need it a couple of players in this other than the cell itself we're going to have to produce mitotic
spindles — we've talked about these before
when we talked about cytoskeleton they're made of microtubules and they are
produced by something known as the
centrosomes you're going to have to be very very careful
with the "C" words in this section there on many of them!!
chromosomes, chromatin, chromatid Centrosomes, centromeres! you're going to
need to make yourself a list to kind of give yourself definitions for what is going on these mitotic spindles are required – they are
actually going to be the movers of the
chromosome In interphase this growth synthesis of DNA
and growth that we just looked at starts us
into prophase You see out chromosomes are in the "X" form they are in their sister chromatid – replicated
state.
they better be! we went through DNA
synthesis! so they have to be replicated at this point they are held together by that centromere that
we mentioned here are centrosomes
beginning to build mitotic spindles and this phase I remember as "Plain to see" "P" [in Prophase] "P" [Plain to see] and what I mean is I can clearly see the
chromosomes inside my nucleus remember the purple is the nucleus in prometaphase we're going to break down
the nucleus you see the nucleus has disappeared inside
the cell and then this spindle fibers of these
microtubules are going to reach out and grab on to the centromere in the middle of the chromosomes and you
see they are coming from both sides and the idea is we want and now attach to
separate the sister chromtids so that we can put them
into two new cells metaphase "M" is for middle all of the chromosomes are lined up in the
middle along something known as the
metaphase plate you see they are all quite organized sitting here in the middle oriented all the
same way so that in anaphase we can pull
apart "A" for apart! Pull aparat the sister chromatids and you see as soon as they're no longer
connected we now call them chromosomes we only talk about them being chromatids
when they all are connected together at that
centromere! Telophase – Telophase = two nuclei so the cells are coming going to come apart right here in the middle through cytokinesis and you see these little
purples spots those are pieces of the nuclear envelope that are reforming for that nuclear membrane we talked about
before so they're gonna form to new nuclei and when
that occurs this cleavage furrow — this split in the middle
— is going to squeeze together and actually
literally pinch these two cells apart as the plasma
membrane touches in the middle so this is what looks like is it starts to fold in
during this process of squeezing in and then
separating these two cells it actually occurs like a string on the hood of your hoody — if you
pull it really tight you know how it pinches
together? that's exactly what's happening – there is a
contracting ring of microflimaents that are
going to pinch together and actually pinch the plasma membrane together so that
the cell will then become two separate cells in the end and the
whole idea is to build these two daughter cells with two nuclei and these are perfect copies because we did mitosis so that produces perfect copies of our cells now this process works exactly the same in
plants up to this point you go back to prophase prometaphase
metaphase anaphase telophase all are the same until cytokinesis what do you think the problem is with plants
in cytokinesis?? remember they have a cell wall! this is a problem!! cell wall is not going to
pinch shut the plasma membrane on the inside will! just
like in animals! but … the problem is the cell wall — we actually have
to grow something known as the cell plate that the cell plate will actually start building from the middle and eventually divide the cell
in half so that each new cell will have cell wall and plasma membrane now in this process we look at this cell — these two new daughter cells are
going to be smaller than the original parent
cell because this cell wall has kept them from growing too much larger during
this process and we kind of keep dividing until we get the
smaller cells now that doesn't mean that plant cells will become infinitely small they will take time to grow so now these two
daughters cells will go in to interphase just like animal cells and they'll go through
growth synthesis and growth they just seem to get much smaller during this division
because of that cell wall — just keep that in
mind .

Cell Division: Prokaryotic vs. Eukaryotic – .

CellDivision_Mitosis (cc only) – In the eukaryotic cell cycle we go through a number of different phases – the first is
interphase this is essentially the rest and growth phase we also look at replication of the DNA only occurring in this phase – G1 is growth this is the start of the entire cycle "S" is synthesis of DNA or replication of the DNA only G2 we look at more growth if we're going to divide a cell in half — it has to
get bigger first so the cell grows and grows
and grows and then we go through mitosis or cell division mitosis is the division of the nucleus cytokinesis is division of the cytoplasm or the cell itself so in this phase that we start so this is our start point we're going to grow go through DNA synthesis or replication we are gonna grow again and then we're gonna divide so mitosis is division of the nucleus and of the cell itself as we mentioned on a 24 hour cycle which is roughly what it
takes for your cell to go through an entire
cycle of cell division or the entire cell cycle as we refer to it this whole process of division takes about 1
hour the rest takes about 23 hours depending on the cell now this might seem like a long time — it's not
particularly a long time because you have got
to remember every cell in your body that is active is going
through this every single day now when we talk to a prokaryotes — that
binary fission — only takes about 20 minutes so the complexity of the cells with growing
and orgtanelles and having to go through a lot more DNA replication and processing takes
much much much longer than we saw in the prokaryotes mitosis has six major stages that we're going to look at prophase – prometaphase – metaphase – anaphase – telophase and
cytokinesis – one of these you already know
all cytokinesis we said is cell division we are going to need it a couple of players in this other than the cell itself we're going to have to produce mitotic
spindles — we've talked about these before
when we talked about cytoskeleton they're made of microtubules and they are
produced by something known as the
centrosomes you're going to have to be very very careful
with the "C" words in this section there on many of them!!
chromosomes, chromatin, chromatid Centrosomes, centromeres! you're going to
need to make yourself a list to kind of give yourself definitions for what is going on these mitotic spindles are required – they are
actually going to be the movers of the
chromosome In interphase this growth synthesis of DNA
and growth that we just looked at starts us
into prophase You see out chromosomes are in the "X" form they are in their sister chromatid – replicated
state.
they better be! we went through DNA
synthesis! so they have to be replicated at this point they are held together by that centromere that
we mentioned here are centrosomes
beginning to build mitotic spindles and this phase I remember as "Plain to see" "P" [in Prophase] "P" [Plain to see] and what I mean is I can clearly see the
chromosomes inside my nucleus remember the purple is the nucleus in prometaphase we're going to break down
the nucleus you see the nucleus has disappeared inside
the cell and then this spindle fibers of these
microtubules are going to reach out and grab on to the centromere in the middle of the chromosomes and you
see they are coming from both sides and the idea is we want and now attach to
separate the sister chromtids so that we can put them
into two new cells metaphase "M" is for middle all of the chromosomes are lined up in the
middle along something known as the
metaphase plate you see they are all quite organized sitting here in the middle oriented all the
same way so that in anaphase we can pull
apart "A" for apart! Pull aparat the sister chromatids and you see as soon as they're no longer
connected we now call them chromosomes we only talk about them being chromatids
when they all are connected together at that
centromere! Telophase – Telophase = two nuclei so the cells are coming going to come apart right here in the middle through cytokinesis and you see these little
purples spots those are pieces of the nuclear envelope that are reforming for that nuclear membrane we talked about
before so they're gonna form to new nuclei and when
that occurs this cleavage furrow — this split in the middle
— is going to squeeze together and actually
literally pinch these two cells apart as the plasma
membrane touches in the middle so this is what looks like is it starts to fold in
during this process of squeezing in and then
separating these two cells it actually occurs like a string on the hood of your hoody — if you
pull it really tight you know how it pinches
together? that's exactly what's happening – there is a
contracting ring of microflimaents that are
going to pinch together and actually pinch the plasma membrane together so that
the cell will then become two separate cells in the end and the
whole idea is to build these two daughter cells with two nuclei and these are perfect copies because we did mitosis so that produces perfect copies of our cells now this process works exactly the same in
plants up to this point you go back to prophase prometaphase
metaphase anaphase telophase all are the same until cytokinesis what do you think the problem is with plants
in cytokinesis?? remember they have a cell wall! this is a problem!! cell wall is not going to
pinch shut the plasma membrane on the inside will! just
like in animals! but … the problem is the cell wall — we actually have
to grow something known as the cell plate that the cell plate will actually start building from the middle and eventually divide the cell
in half so that each new cell will have cell wall and plasma membrane now in this process we look at this cell — these two new daughter cells are
going to be smaller than the original parent
cell because this cell wall has kept them from growing too much larger during
this process and we kind of keep dividing until we get the
smaller cells now that doesn't mean that plant cells will become infinitely small they will take time to grow so now these two
daughters cells will go in to interphase just like animal cells and they'll go through
growth synthesis and growth they just seem to get much smaller during this division
because of that cell wall — just keep that in
mind .