Demonstrate how 200 different cells came from a single fertilized ovum ?​

Answer:

Humans are not that different from other animals, but vary in the finer detail.

Indeed most amniotes (terrestrial organisms with fetuses surrounded by membrane) work pretty well along the same principles, and there’s also much in common as far back as you want to go, really, on land or in water.

And my next semi-random thought is to say that cellular differentiation, like real estate (apparently), is all about location, location, location. Where the cells are, or where they came from, seems to matter a lot.

Actually, it’s more about layers. Like an onion. Or a cake. (I can’t believe I’m writing this, and apologies to any Shrek fans out there.)

What I mean to say is that some understanding of developmental embryology will help here. To simplify things enormously, our adult cell types ultimately arise from embryonic stem cells. These stem cells are multi-purpose and programmable, or pluripotent in a sense, and capable of making whatever type or form of cell is requested. They just need to be “told” what to do. And just tiny bits of code do exactly that, flipping switches on or off as required, based on cues like orientation, chemical gradients, and proximity.

Now a quick read of the links above will explain it all, but I’ll press on anyway. Out of that initial programming arises our ‘germ layers’, the mesoderm, the ectoderm and the endoderm. We are, after all, triploblastic. 3 layers, get it?

But you knew that.

In case you didn’t, these layers in effect give you a scaffold or more accurately perhaps a tube comprising an inside, outside, and a middle. Where your cells are hanging out in that tube matters, in that they pick up on their location and auto-magically become functionally relevant to that space. In a sense, I mean. Refer back to location, location, location.

Just knowing that pattern of proximity, gradients, and orientation more than simply sets the scene. Whether you work forwards or backwards from there, you will hopefully see that these “germ layers” derive quite simply from a much earlier differentiation, and then complexify. In that sense you have your answer - a complex set of diverse cell types arises by differentiation from an earlier, simpler differentiation. Which sounds a bit clunky when I write it out, but it gives a general idea.

So how does this complicated process happen?

Well, as I mentioned chemical gradients are probably to blame here. And it actually starts before fertilisation, in that the egg itself is already semi-structured and bathed in chemicals with a high-low gradient of some sort. In that sense it’s giving cellular differentiation a head start (there’s a pun there), by setting up some sort of polarity from the beginning. At the very least we get some ends happening, or a top and a bottom if you like.

Now, again simplifying things enormously, your average fertilised egg, or zygote, has by definition a complete set of your DNA ready and waiting, which contains the code for every protein-making gene, plus transcription factors, plus whatever else gets copied for various reasons, including those we haven’t teased out as yet.

Note that those transcription factors really matter. We may have around 20,000 protein-expressing genes, but we also have some 1,500 transcription factors that seem to switch the genes on, off, or arguably and effectively somewhere in between. Well, they work in combination and by that we get a huge amount of variation in expression, and thus our cellular diversity as well.

And all of that DNA goodness is sitting in that zygote, bathed in chemicals that may vary very slightly from top to bottom and side to side as it were, by concentration and by other traits, like temperature. Several such things interact, including orientation and proximity to neighbours, but let’s assert (based on experiments) that the gradient is important, and that it continues to guide the “differentiation” process as new cells are born.

Which is to say that by this process of reading the DNA and expressing only the genes that are switched on by the helpful and gradient-sensitive (say) transcription factors, we get set up to form those 3-D axes and the scaffolding that will guide our cellular replication strategy. Which then produces a result that with each round of replication becomes subtly different and more diverse. Over time the subtlety gives way to more recognisable layers and specialisation in function.

Perhaps not the neatest, clearest explanation but the quickest and least baffling one I can come up with right now. As always, read the links to get a better grasp.

Answer:

During the development of an organism, cells differentiate into many distinct cell types. How does a single fertilized egg cell develop into so many different types of specialized cells? ... They both cannot produce all cells. Multipotent- limited to replacing cells in the tissue where they are found.

Water availability poses the single greatest limitation to plant life in deserts. The amount of moisture that is available for plants to
use is determined by the unique features of the soil. Which term describes the capacity of the soil to allow fluids to pass through it?
A)
texture
B)
composition
C)
particle size
D)
permeability
Frology Interactions of living

Break question


what pets would you want




(p.s. could you please answer one of my questions)​

Protein synthesis consumes four high-energy phosphate bonds per added amino acid. Transcription consumes two high energy phosphate bonds per added nucleotide. Calculate how many protein molecules will have been made from an individual mRNA at the point when the energy cost of translation is equal to the energy cost of transcription. Assume that the nucleotides in the coding portion of the mRNA constitute 5% of the total that are transcribed.

The image shows a cell placed in an aquatic environment. Using your
knowledge of water tonicity, what type of environment was the cell placed
in, and what effect will this have on the cell?
The environment outside of the cell is hypertonic, and the cell will swell.
The environment outside of the cell is hypertonic, and the cell will shrink.
The environment outside of the cell is hypotonic, and the cell will swell.
The environment outside of the cell is hypotonic, and the cell will shrink.

which are characteristics of epithelial cells? Select two options.( Answer Needed ASAP)​

Cellular Respiration and Energy

PLZ HELP ASAP
MARKING

fertilization of an egg to form a zygote takes place in?

A.urethra
B.uterus
C.cervix
D.fallopain tube​

1.) A person walks 12.5 km in 1.9 h. What is the person's
average velocity in km/h and m/s?

The original source of the matter in food

What observation supports the claim that earth rotates

Which is NOT an example of a fossl fuel
O Coal
O Oll
O Water
O Natural gas
Please help ASAP

competition a type symbiotic relationship is where

plesss help me I'm in die mode right now ples helpp​

The diagram below shows three families. Which set of parents has the highest fitness?

A
the parents of the single child

B
the parents of two children

C
the parents of the big family

this type of consistent adaptation between two species is known as

One species called the naked mole-rat, has some unique differences. They have a social structure similar to that of ants and bees, they are smaller in size and are mostly ectothermic. They live in harsh, dry scrub land habitats and forage mainly on underground tubers which are widely dispersed. Why you think this species evolved back to an ectothermic life style rather than staying endothermic like all other mammals

Which one 1,2,3,4…………………

PLEASE HELP!!!!!!!!!!​

The diagram shows the box for an element in the periodic table.
13
Al
Aluminum
27.0
What is the atomic number of the element shown?

Select the term that best fits the following definition: Tells what elements
a compound contains and the number of those atoms *
O Covalent Bond
O lonic Bond
O Compound
O Chemical Formula

A scientist is observing a new species of organism. She observes that from generation to generation many of the organisms’ offspring have adaptations that their parents did not have. This organism is most likely reproducing through_______.

a. sexual reproduction
b. budding
c. asexual reproduction
d. binary fission

judging from the diagram, tropical cyclones are powered by

Detection of a light is
coming from a car is
and interpreting the light as
Select one:
a. Sensation perception
b. Consciousness: unconsciousness
e Bods: cons
O d. Energy: gestalt​

6. Calculate the kinetic energy of a baseball thrown by Aroldis Chapman, who holds the world record for fastest pitch. The baseball
has a mass of 0.145 kg and velocity of 47.0 m/s.
a. 3.40J
b. 320 J
c. 6.82 J
d. 160J

What is homeostasis?

punnett Square st. Patrick's Day worksheet... did anyone have the answers..ughh... so confusing!!​

Help fast plz!!!
In a population of moths, wing color became darker over time. Which of the
following is the best evidence that the change in wing color was an evolutionary change?
a) The size of the moth population changed.
b) The average length of the moths' dark wings increased.
c) The number of eggs that females laid during each breeding season increased.
d) The frequencies of the alleles for dark wing color in the moth population
changed.

Apply: Suppose a template strand of DNA had the following sequence: T A C G G A T A A C T A C C G G G T A T T C A A What would be the complementary strand of mRNA?

Sexual harassment in the workplace is a crime when committed by anyone, regardless of position, role, or gender. Please select the best answer from the choices provided ОТ OF​