It's all just talk
the structure of a cell
#mitochondria #nucleus #cytoplasm
https://www.plantyou.com/vegan-black-bean-peanut-butter-brownie-recipe/
#mitochondria #nucleus #cytoplasm
https://www.plantyou.com/vegan-black-bean-peanut-butter-brownie-recipe/
The cells of all animals, plants, and fungi have an impressive complexity, with a variety of compartments specialized in various tasks, like generating energy, digesting proteins, or holding DNA. If you look at bacteria or archaea, however, their interiors are essentially featureless. How did this cellular complexity come about?
A key thing that has limited our understanding here is that we've never gotten a sense of what the ancestors of complex cells looked like. Over the last several years, we've found increasing genetic evidence of the existence of modern descendants of these organisms, but we've never been able to grow them to have a look at them. On Tuesday, however, a paper reports on the success of a decade-long attempt to get one of these to survive in culture. And the resulting microbes look very weird—but weird in a way that hints at how complex cells evolved.
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Complex cells, called eukaryotes, carry a mixture of three types of genes. Some come from the bacteria that were incorporated as mitochondria and chloroplasts. Others seem to have evolved after the origin of complex cells. And yet others seem to have originated in archaea, a distinct type of simple, single-celled organisms that were once classified as bacteria. This provided key support to the idea that complex cells originated when archaea somehow swallowed bacteria and started using them to produce energy. (src) DOI
What's a genome?
BRCA2 gene, DNA repair associated
Is involved in repairing damaged DNA. In the nucleus of many types of normal cells, the BRCA2 protein interacts with several other proteins to mend breaks in DNA. These breaks can be caused by natural and medical radiation or other environmental exposures, and they also occur when chromosomes exchange genetic material in preparation for cell division. By helping to repair DNA, the BRCA2 protein plays a critical role in maintaining the stability of a cell's genetic information.
Researchers suspect that the BRCA2 protein has additional functions within cells. For example, the protein may help regulate cytokinesis, which is the step in cell division when the fluid surrounding the nucleus (the cytoplasm) divides to form two separate cells. Researchers are investigating the protein's other potential activities.
Researchers have identified more than 1,800 mutations in the BRCA2 gene. BRCA2 gene mutations likely reduce the BRCA2 protein's ability to repair DNA. Many of these mutations are associated with an increased risk of cancer. (src)
Proteins are made up of hundreds of smaller units called amino acids that are attached to one another by peptide bonds, forming a long chain. You can think of a protein as a string of beads where each bead is an amino acid. src
When a gene is activated by signals from inside or outside the cell, it makes a molecular message (called an RNA) that contains all the information needed to make whatever that gene makes. We now know that over 95% of our genes can actually make several different types of messages, depending on the needs of the cell.
mitochondria = the structures that produce energy in cells
https://theconversation.com/ageing-in-human-cells-successfully-reversed-in-the-lab-101214
The DNA inside each of your cells is longer than you are, but packs down into a space smaller than you can see.
Stretched DNA length in each human cell is about 2 meters.
All the DNA in all your cells put together would be about twice the diameter of the Solar System. src
Imagine that the network of neurons in the brain is engaged in something like the party game Telephone. Each neuron is covered with proteins and molecular channels that enable it to fire and pass messages. When one neuron fires, it releases a flood of neurotransmitters that excite or inhibit the firing of the next neuron down the line.
https://www.quantamagazine.org/longevity-linked-to-proteins-that-calm-overexcited-neurons-20191126/
The REST protein inhibits the production of some of the proteins and channels involved in this process, reining in the excitation.
Long-lived humans have unusually low levels of proteins involved in excitation.
Our memories and thoughts are the result of patterns of electrical and chemical activity in the brain. A key part of the activity happens when branches of neurons, much like electrical wire, interact at certain junctions, known as synapses. Every 2 or 20 minutes, your synapses are going up or down to the next size. The synapses are adjusting themselves according to the signals they receive. There are 26 categories of sizes of synapses. The waking adult brain generates about 20 watts of continuous power—as much as a very dim light bulb.
Every minute, each human cell constructs up to 7,500 ribosomes — essential intracellular factories that decode instructions from genes to make all the proteins in the body. Ribosomes are assembled from four distinct ribosomal RNA (rRNA) molecules and 80 different proteins, which form small and large subunits, in a complex process involving more than 200 assembly factors.
Skin reproduces about 30,000 to 40,000 cells every minute. (++video)
You may have heard mitochondria referred to as the 'powerhouses' of the cell. It's funny, they do literally run like a dam generating hydroelectric power! - They pump protons (positively charged particles) one way, then use them as they slide back to run a kind of motor that makes a small energetic molecule used by many entities in the cell. One concept that comes up when people talk about mitochondria is 'oxidative stress' - the idea that if molecules are very reactive (say they have oxygen, acquire some extra electrons, and now want to discharge them onto other molecules), they are likely to interfere with a lot of other molecules in the cell that should be left to their own devices.
Weirdly, the story has turned on its head over time. It's true that it is bad to pump an animal full of reactive oxygen species, and that you can make a mouse live longer by increasing the level of proteins that are supposed to clean up mitochondria. But you can also mutate things that should be helping the mitochondria, and end up increasing lifespan! It's counterintuitive, and one hypothesis is that a little bit of stress is good because it forces your cells to put up their defenses and ramp up production of molecules that neuter the reactive oxygen species. But we don't really know. src