#centrioles

[biologist4ever]

Cell Division: Stages of Mitosis

[bpod-bpod]

Centriole Building

The centriole – an organelle vital for the faithful separation into each daughter cell when a cell divides – is composed of an assembly of proteins. Using expansion microscopy, this study correlates the spatial location of 24 of those proteins with structural features of the human centriole, and then models the molecular architecture of the centriole as it assembles (shown here)

Read the published research article here

Video from work by Marine H. Laporte and colleagues

University of Geneva, Department of Molecular and Cellular Biology, Faculty of Sciences, Geneva, Switzerland

Video originally published with a Creative Commons Attribution 4.0 International (CC BY-NC 4.0)

Published in Cell, April 2024

You can also follow BPoD on Instagram, Twitter and Facebook

[sciencesolutions]

[nepenthean-sleep]

lab courses will have you look at the grungiest slide in the universe with no stain on it and ask you to identify the centrioles. like sir that is not happening but i can identify all the floaters in my eye for you instead

[nikoisme]

i've officialy lost it.

[er-cryptid]

Organelles

Nucleus -- located near the center of the cell -- contains the genetic material of the cell (DNA) and nucleoli -- site of ribosome and messenger RNA synthesis

Nucleolus -- located in the nucleus -- site of ribosomal subunit assembly

Ribosomes -- located in the cytoplasm -- site of protein synthesis

Rough Endoplasmic Reticulum -- located in the cytoplasm -- has many ribosomes attached -- site of protein synthesis

Smooth Endoplasmic Reticulum -- located in the cytoplasm -- site of lipid synthesis -- participates in detoxification

Golgi Apparatus -- located in the cytoplasm -- modifies protein structure -- packages proteins in secretory vesicles

Secretory Vesicle -- located in the cytoplasm -- contains materials produced in the cell -- formed by the Golgi apparatus -- secreted by exocytosis

Lysosome -- located in the cytoplasm -- contains enzymes that digest material taken into the cell

Mitochondria -- located in the cytoplasm -- site of aerobic respiration -- major site of ATP synthesis

Microtubule -- located in the cytoplasm -- supports cytoplasm -- assists in cell division -- forms components of cilia and flagella

Centrioles -- located in the cytoplasm -- facilitate the movement of chromosomes during cell division

Cilia -- located on the cell surface with many on each cell -- move substances over the surface of certain cells

Flagella -- located on sperm cells -- one per cell -- propels sperm cell

[cloudcountry]

kinetochores are so weird like why is there a whole other part of the centriole microtubles attach to why cant they just be like "ya centrioles are were the bullshit happens" like what?

[abwwia]

Lezley Irene Saar is an African American artist whose artwork is responsive to race, gender, female identity, and her ancestral history. Her works are primarily mixed media, 3-dimensional, and oil & acrylic on paper and canvas.

Her mother Betye Saar (née Brown), is an African-American assemblage artist. Via Wikipedia

#bornonthisday Lezley Saar

Centrioles Later, 2014

Let's talk of space sadness, 2014

Detail “Not born under a rhyming planet”

Mitochondrial Muses, 2014

All from the Monad Series

Let's read it together again: Betye Saar, Her Daughters, and the House That Never Stopped Making Art

www.harpersbazaar.com/culture/features/a36182098/betye-saar-daughters-in-conversation/

The pioneering artist and her three daughters on family, creativity, and why being able to see beauty, even in difficult times, is the true mother of invention. (2021)

#TracyeSaarCavanaugh #AlisonSaar #BetyeSaar #LezleySaar #artherstory #artbywomen #womensart #palianshow #art #womenartists #femaleartist #artist #daughters

[faer-mulberries]

A Midcellmmer Night’s Dream

Our cell membranes press against each other, and I know I’m in love. Accurate to their name, G2trude is in the G2 phase of the cell cycle. Through their semipermeable cell membrane, I can see enzymes checking that their genetic information is all correct. If I had cheeks and blood to blush with right now, I would. Unlike G2trude, I am only in the G1 phase. I’m still growing, developing organelles, and other things that probably seem super juvenile to G2trude. Hey, someday they’ll be back to where I am though. Kinda. Soon enough, they’ll go into mitosis and after that they’ll be 2 daughter cells in G1. Will they both be G2trude then? Or just one? Or are they completely their own cells? Who really knows, philosopher cells don’t come around these parts. Or any parts, they don’t exist.

It would be easier if we were gametes. We wouldn’t go thru mitosis, and we could be together and be together forever. However, we are skin cells, stuck in the epidermis, stuck in the cell cycle.

We, us, G2trude and Trevor

stuck in cell cycle forever

G1, S, G2, mitosis

believing you love me is psychosis

Something happens! I watch centrioles head to opposite sides of the cell. Oh man, mitosis already? Maybe our phase gap isn’t that bad after all! I watch in silence, for I am a cell and have nothing to make noise with, as G2trude starts prophase. From the centrioles spring forty spindle fibers. The nuclear envelope breaks down, and the chromosomes line up in the middle. I watch in fear and fascination. I can’t believe I’m witnessing this coming of phase. The spindle fibers grab onto the centromeres and pull them apart. I CAN’T WATCH!!! But I do anyway. Oh golly gee, G2trude isn’t their usual shape anymore! They look like two suns, still attached at the side. If only they e could merge together like that! Only gametes merge though. As said before, we are skin cells stuck in the epidermis.

We, us, G2trude and Trevor

stuck in th’epiderm forever

If we were gametes we’d be one

Mr. and Mrs. Trevor, why, that’s fun!

The nuclear envelopes are forming again, around the chromatids. Then, I watch as G2trude is no more. If I had tears to cry with, I would cry. No. SOB. I now know that neither of them is really my G2trude. They’re their own cells. I’ll name them Epinand Dermis.

G2trude isn’t the only one who’s changed however. I’m now in S phase. Synthesizing phase. My DNA is getting replicated into perfect copies. Soon, I’ll be in G2 phase just like G2trude was. Then in M phase: Then G1 again. That’s cell cycle for you. Never ending, never escapable. Predetermined.

This is the story of G2trude and Trevor,

Now it’s time to say cellut forever

[biologist4ever]

Cell Division: Stages of Mitosis

[bpod-bpod]

Centriole Formation

Protein called SAS-6 role in the maintenance of the architecture of centrioles – specialised structures involved in organising cell contents during division – as they form early in embryonic development in cells that generate mouse embryonic stem cells

Read the published article here

Image from work by Marta Grzonka and Hisham Bazzi

Department of Cell Biology of the Skin and Department of Dermatology and Venereology, Medical Faculty, University of Cologne, Cologne, Germany

Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)

Published in eLife, February 2024

You can also follow BPoD on Instagram, Twitter and Facebook

[marie-is-seein-stars]

Mitosis Help- College Biology (AP)

Introduction

What do your intestines, the yeast in bread dough, and a developing frog all have in common? Among other things, they all have cells that carry out mitosis, dividing to produce more cells that are genetically identical to themselves.

Why do these very different organisms and tissues all need mitosis? Intestinal cells have to be replaced as they wear out; yeast cells need to reproduce to keep their population growing; and a tadpole must make new cells as it grows bigger and more complex.

What is mitosis?

Mitosis is a type of cell division in which one cell (the mother) divides to produce two new cells (the daughters) that are genetically identical to itself. In the context of the cell cycle, mitosis is the part of the division process in which the DNA of the cell's nucleus is split into two equal sets of chromosomes.

The great majority of the cell divisions that happen in your body involve mitosis. During development and growth, mitosis populates an organism’s body with cells, and throughout an organism’s life, it replaces old, worn-out cells with new ones. For single-celled eukaryotes like yeast, mitotic divisions are actually a form of reproduction, adding new individuals to the population.

In all of these cases, the “goal” of mitosis is to make sure that each daughter cell gets a perfect, full set of chromosomes. Cells with too few or too many chromosomes usually don’t function well: they may not survive, or they may even cause cancer. So, when cells undergo mitosis, they don’t just divide their DNA at random and toss it into piles for the two daughter cells. Instead, they split up their duplicated chromosomes in a carefully organized series of steps.

Phases of mitosis

Mitosis consists of four basic phases: prophase, metaphase, anaphase, and telophase. Some textbooks list five, breaking prophase into an early phase (called prophase) and a late phase (called prometaphase). These phases occur in strict sequential order, and cytokinesis - the process of dividing the cell contents to make two new cells - starts in anaphase or telophase.

Stages of mitosis: prophase, metaphase, anaphase, telophase. Cytokinesis typically overlaps with anaphase and/or telophase.

You can remember the order of the phases with the famous mnemonic: [Please] Pee on the MAT. But don’t get too hung up on names – what’s most important to understand is what’s happening at each stage, and why it’s important for the division of the chromosomes.

Late G2 phase. The cell has two centrosomes, each with two centrioles, and the DNA has been copied. At this stage, the DNA is surrounded by an intact nuclear membrane, and the nucleolus is present in the nucleus.

Let’s start by looking at a cell right before it begins mitosis. This cell is in interphase (late G\[_2\] phase) and has already copied its DNA, so the chromosomes in the nucleus each consist of two connected copies, called sister chromatids. You can’t see the chromosomes very clearly at this point, because they are still in their long, stringy, decondensed form.

This animal cell has also made a copy of its centrosome, an organelle that will play a key role in orchestrating mitosis, so there are two centrosomes. (Plant cells generally don’t have centrosomes with centrioles, but have a different type of microtubule organizing center that plays a similar role.)

Early prophase. The mitotic spindle starts to form, the chromosomes start to condense, and the nucleolus disappears.

In early prophase, the cell starts to break down some structures and build others up, setting the stage for division of the chromosomes.

The chromosomes start to condense (making them easier to pull apart later on).

The mitotic spindle begins to form. The spindle is a structure made of microtubules, strong fibers that are part of the cell’s “skeleton.” Its job is to organize the chromosomes and move them around during mitosis. The spindle grows between the centrosomes as they move apart.

The nucleolus (or nucleoli, plural), a part of the nucleus where ribosomes are made, disappears. This is a sign that the nucleus is getting ready to break down.

Late prophase (prometaphase). The nuclear envelope breaks down and the chromosomes are fully condensed.

In late prophase (sometimes also called prometaphase), the mitotic spindle begins to capture and organize the chromosomes.

The chromosomes become even more condensed, so they are very compact.

The nuclear envelope breaks down, releasing the chromosomes.

The mitotic spindle grows more, and some of the microtubules start to “capture” chromosomes.

Anatomy of the mitotic spindle. Diagram indicating kinetochore microtubules (bound to kinetochores) and the aster. The aster is an array of microtubules that radiates out from the centrosome towards the cell edge. Diagram also indicates the centromere region of a chromosome, the narrow "waist" where the two sister chromatids are most tightly connected, and the kinetochore, a pad of proteins found at the centromere.

Microtubules can bind to chromosomes at the kinetochore, a patch of protein found on the centromere of each sister chromatid. (Centromeres are the regions of DNA where the sister chromatids are most tightly connected.)

Microtubules that bind a chromosome are called kinetochore microtubules. Microtubules that don’t bind to kinetochores can grab on to microtubules from the opposite pole, stabilizing the spindle. More microtubules extend from each centrosome towards the edge of the cell, forming a structure called the aster.

Metaphase. Chromosomes line up at the metaphase plate, under tension from the mitotic spindle. The two sister chromatids of each chromosome are captured by microtubules from opposite spindle poles.

In metaphase, the spindle has captured all the chromosomes and lined them up at the middle of the cell, ready to divide.

All the chromosomes align at the metaphase plate (not a physical structure, just a term for the plane where the chromosomes line up).

At this stage, the two kinetochores of each chromosome should be attached to microtubules from opposite spindle poles.

Before proceeding to anaphase, the cell will check to make sure that all the chromosomes are at the metaphase plate with their kinetochores correctly attached to microtubules. This is called the spindle checkpoint and helps ensure that the sister chromatids will split evenly between the two daughter cells when they separate in the next step. If a chromosome is not properly aligned or attached, the cell will halt division until the problem is fixed.

Anaphase. The sister chromatids separate from one another and are pulled towards opposite poles of the cell. The microtubules that are not attached to chromosomes push the two poles of the spindle apart, while the kinetochore microtubules pull the chromosomes towards the poles.

In anaphase, the sister chromatids separate from each other and are pulled towards opposite ends of the cell.

The protein “glue” that holds the sister chromatids together is broken down, allowing them to separate. Each is now its own chromosome. The chromosomes of each pair are pulled towards opposite ends of the cell.

Microtubules not attached to chromosomes elongate and push apart, separating the poles and making the cell longer.

All of these processes are driven by motor proteins, molecular machines that can “walk” along microtubule tracks and carry a cargo. In mitosis, motor proteins carry chromosomes or other microtubules as they walk.

Telophase. The spindle disappears, a nuclear membrane re-forms around each set of chromosomes, and a nucleolus reappears in each new nucleus. The chromosomes also start to decondense.

In telophase, the cell is nearly done dividing, and it starts to re-establish its normal structures as cytokinesis (division of the cell contents) takes place.

The mitotic spindle is broken down into its building blocks.

Two new nuclei form, one for each set of chromosomes. Nuclear membranes and nucleoli reappear.

The chromosomes begin to decondense and return to their “stringy” form.

Cytokinesis in animal and plant cells.

Cytokinesis in an animal cell: an actin ring around the middle of the cell pinches inward, creating an indentation called the cleavage furrow.

Cytokinesis in a plant cell: the cell plate forms down the middle of the cell, creating a new wall that partitions it in two.

Cytokinesis, the division of the cytoplasm to form two new cells, overlaps with the final stages of mitosis. It may start in either anaphase or telophase, depending on the cell, and finishes shortly after telophase.

In animal cells, cytokinesis is contractile, pinching the cell in two like a coin purse with a drawstring. The “drawstring” is a band of filaments made of a protein called actin, and the pinch crease is known as the cleavage furrow. Plant cells can’t be divided like this because they have a cell wall and are too stiff. Instead, a structure called the cell plate forms down the middle of the cell, splitting it into two daughter cells separated by a new wall.

When division is complete, it produces two daughter cells. Each daughter cell has a complete set of chromosomes, identical to that of its sister (and that of the mother cell). The daughter cells enter the cell cycle in G1.

When cytokinesis finishes, we end up with two new cells, each with a complete set of chromosomes identical to those of the mother cell. The daughter cells can now begin their own cellular “lives,” and – depending on what they decide to be when they grow up – may undergo mitosis themselves, repeating the cycle.

[ugotcooneycrossed]

challenge: how many cell organelles can you can you name in the pic you posted

golgi apparatus

endoplasmic reticulum (rough and smooth)

lyosomes

centrioles

mitochondria

cell membrane

nucleus

cytoplasm

��

i did anatomy 😎

[greatmountainfloofsquatch]

When I was but a wee little floofsquatch, about two or so, my mother was studying to be a nurse*. This meant that she had to read a lot of books, of course, and spend a lot of time on schoolwork, but I was a very eager young kid who always wanted to do stuff with Mom. In particular, I loved it when she would read me stories.

In an effort to get me to leave her alone, she decided one day that the only "story" she would offer to read me when it was study time would be her anatomy textbook. So, she plopped me down on her lap and started reading from it, and explaining to me about digestive enzymes, since that happened to be the chapter she was on.

Her attempt to bore me into leaving her alone backfired: I was FASCINATED, and wanted her to read me more of the Enzyme Book! She, meanwhile, discovered that explaining human anatomy and physiology to a bright and inquisitive two year old was actually a pretty good way to study, and so kept at it.

When she was done, I knew the bones of the body, the parts of the cell, the way muscles worked, the circulatory system, pretty much the whole works. Couldn't read yet, but I could see a truck go by while we were on the road with rolled up chain-link fences in it and say "IMMA! LOOK! CENTRIOLES!"

When I got to preschool, I remember one day we were given an outline of a person, and they told us to draw the parts of the body and tell what they were. The teacher was expecting eyes, nose, mouth, ears, hair, hands, feet, and so forth.

That is NOT what she got from me.

I remember saying, at one point, "I couldn't add the muscles, they'd cover over everything else." I also remember that the poor teacher had no idea how to spell "xyphoid process". Of course, I was no help, since I couldn't spell it either, or read, for that matter. But she gamely went along with me, looking baffled, and I think she might have suspected I was making things up, until she showed my mother, who burst out laughing and explained to her about the Enzyme Book.

Epilogue: I still remember this stuff, some 40+ years later.

*My mother eventually became a teacher, not a nurse.

[blogpostatron3000]

i think the centrosome is straight up not real and we should just focus on centrioles which are demonsrably present. Like if the centrosome is "present in plant cells" how did we even determine that. It foesnt. Have a membrane. And all it is is a container for the centrioles. Why is it theee.

[ribosome-papers]

The Unkempt RNA binding protein reveals a local translation program in centriole overduplication

bioRxiv: http://dlvr.it/TBFvqK