DarthJudie/biosetpart1 · Datasets at Hugging Face

title stringlengths 7 100	text stringlengths 1 16k
Meiosis	There's only one, two, three and over here one, two, three.
Meiosis	So we technically have haploid cells.
Meiosis	They have one of each kind of chromosome.
Meiosis	Like look at this one with the two lines at the top.
Meiosis	They have one of each kind.
Meiosis	So why do we need to divide again?
Meiosis	Why do we need meiosis number two?
Meiosis	Well, because these chromosomes are duplicated.
Meiosis	Because these chromosomes still have twice as much DNA.
Meiosis	So even though they're haploid with only three chromosomes in each cell, they have their sister chromatids attached.
Meiosis	So we need to divide again and go through a second round of division.
Meiosis	So I'm not really showing prophase two.
Meiosis	Basically it's the same like the nuclear envelope breaks down.
Meiosis	And then we move into metaphase two where the chromosomes are going to move to the middle of the cell.
Meiosis	So basically up here we're looking at meiosis two.
Meiosis	This part is very similar to mitosis.
Meiosis	You'll see here the sister chromatids and anaphase two get pulled apart to opposite sides of the cell.
Meiosis	And then you're going to have your telephase two and cytokinesis where we end up with four genetically different haploid cells.
Meiosis	So remember we started with 2N equals six.
Meiosis	And now look, each of these cells have three.
Meiosis	And if you really look at them, they're all different.
Meiosis	We get four genetically different haploid cells at the end.
Meiosis	And the reason they're different is because of that crossing over, creating recombinant chromosomes, but also the way the homologous pairs lined up in the middle of the cell.
Meiosis	So for example, here let me write on this.
Meiosis	So if I had like here one option and then maybe like the homologous pairs, but very easily couldn't have been where maybe like all of the purple ones are on the left.
Meiosis	And then some of them, all of these, like that would create different combinations of chromosomes in the gametes.
Meiosis	So that independent assortment is another source of variation.
Meiosis	Now in males, the next step would be to add tails and make the cells into sperm.
Meiosis	It goes through spermatogenesis.
Meiosis	Now in females though, you might be thinking, or maybe you're not, but in general for human females, we go through meiosis once a month to produce an egg.
Meiosis	But you just learned that in meiosis, we make four cells, four gametes at the end of meiosis.
Meiosis	However, when a female gets pregnant, she doesn't have quadruplets every time.
Meiosis	And that's because in human females during the meiosis process, one of the cells, like the cytoplasm doesn't divide equally.
Meiosis	And basically one of the cells hogs all of the cytoplasm and we're left with one egg or one ovum and three polar bodies.
Meiosis	And the three polar bodies will actually disintegrate and the parts will get reused.
Meiosis	So we get one egg at the end of meiosis and three polar bodies.
Meiosis	So this is just a visual to kind of show that unequal division of the cytoplasm to make that one mature egg.
Meiosis	All right.
Meiosis	I think that's the end of my discussion on meiosis.
Meiosis	So great job.
Chapter 45 Hormones and the Endocrine System	Alright, so chapter 45 is all about the endocrine system and hormones.
Chapter 45 Hormones and the Endocrine System	Hormones, we've talked about previously, they act as your long-distance regulators, the chemical signals that are secreted into your circulatory system and are able to send out messages throughout the body.
Chapter 45 Hormones and the Endocrine System	They are able to reach all parts of the body through your body fluids, but they can only actually interact with cells, the target cells that have receptors for them.
Chapter 45 Hormones and the Endocrine System	There are two systems that are able to coordinate communication throughout your body, your endocrine system and your nervous system.
Chapter 45 Hormones and the Endocrine System	The endocrine system, the hormones are able to go out throughout the whole body, they're more longer-acting responses, they take a little longer to get going, they impact such processes as reproduction, development, metabolism, growth, behavior, while the nervous system uses high-speed electrical signals along neurons which are able to regulate specific cells.
Chapter 45 Hormones and the Endocrine System	So endocrine signaling is one way information is transmitted.
video_title	transcription
Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)	Okay, so in this video I will compare and contrast primary and secondary succession.
Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)	It's really from my EP bio class.
Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)	It's my final video in community ecology, but if you're just watching this to learn about succession, it should work for you as well.
Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)	So in general, ecological succession is basically like the changing or formation of an ecosystem.
Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)	And we're going to look at primary succession first, and primary succession starts out on bare rock.
Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)	So I took this picture in Volcanoes National Park in Hawaii last year.
Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)	So here is some like, like an active volcano, right?
Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)	So about, I don't know how far, 10 minutes, 15 minute drive from this location, here's the crater of a different volcano, and my family, we walked across it.
Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)	So really when we look at primary succession, it starts out like, how do we start with a brand new volcanic island and then eventually end up with biodiversity?
Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)	Like what are the changes that happen in the plant, in animal communities in that region over the hundreds or thousands of years?
Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)	So here's also a picture of Craters of the Moon National Monument in Idaho.
Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)	Yeah, Idaho.
Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)	And you can see like this is lava rock, but you can see that there's small amounts of plants beginning to grow on it.
Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)	So in succession, we're going to start with a discussion of how do you start on bare rock and then end up with a whole forest of biodiversity.
Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)	So oh, one last example is the Galapagos Islands.
Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)	So the Galapagos Islands are volcanic islands, and you can see from this aerial map, the Valdez are like the peaks of the volcanoes that are now underwater.
Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)	But the Galapagos are volcanic rock, and like here is a picture I took from like a cliff top when I was in Galapagos in 2018, and you can see there's plants and life on these islands, enough to support wildlife.
Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)	Here I am with one of the...
Lasseter AP Bio 20 Gene Expression	Alright, so today we're talking about gene expression.
Lasseter AP Bio 20 Gene Expression	Now one really interesting thing in biology is that all the cells from the same organism contain the same genome, the same bulk of DNA.
Lasseter AP Bio 20 Gene Expression	However, they're not going to transcribe all of it to create proteins for every single one of the genes.
Lasseter AP Bio 20 Gene Expression	In fact, in any one of our cells we may only be expressing 10,000 genes of the 20 or so thousand that we actually have.
Lasseter AP Bio 20 Gene Expression	Now part of this is because of differentiation.
Lasseter AP Bio 20 Gene Expression	In all of our cells, so for example think of a liver cell and then think of a neuron and then think of a white blood cell.
Lasseter AP Bio 20 Gene Expression	All these are extremely different in shape and function, but they all have the same genome even though they're totally different cells.
Lasseter AP Bio 20 Gene Expression	So how does this come about?
Lasseter AP Bio 20 Gene Expression	It's basically all about how they are going to make and accumulate different RNA and proteins.
Lasseter AP Bio 20 Gene Expression	So this is all part of gene expression in those different cells and how they're being expressed differently.
Lasseter AP Bio 20 Gene Expression	So what regulates that?
Lasseter AP Bio 20 Gene Expression	A lot of it's going to be on the actual level of initiating transcription.
Lasseter AP Bio 20 Gene Expression	So we'll talk about that in a little bit.
Lasseter AP Bio 20 Gene Expression	Some proteins though are going to be transcribed and produced in all cells.
Lasseter AP Bio 20 Gene Expression	So some proteins are actually housekeeping proteins that are necessary no matter what cell it is, such as RNA polymerase.
Lasseter AP Bio 20 Gene Expression	You're pretty much going to need that one in all of your cells.
Lasseter AP Bio 20 Gene Expression	However, there's a lot of proteins in RNA that are specialized and will only appear in certain cells based on what the cell has to do or how it functions.
Lasseter AP Bio 20 Gene Expression	All right, so moving on.
Lasseter AP Bio 20 Gene Expression	Some of these things that will turn genes on and off are going to be extracellular cues, meaning they're coming from outside of the cell.
Lasseter AP Bio 20 Gene Expression	And a lot of cells that are different can respond differently to the same signal.
Lasseter AP Bio 20 Gene Expression	So our fat cells and our liver cells respond differently based on this glucocorticoid hormone.
Lasseter AP Bio 20 Gene Expression	Our liver cells, for example, will release glucose and now that they no longer need to store it for later on.
Lasseter AP Bio 20 Gene Expression	Now a lot of this regulation is going to be at the level of transcriptional control.
Lasseter AP Bio 20 Gene Expression	So how we're controlling how transcription happens in the cell.
Lasseter AP Bio 20 Gene Expression	Now these can be done through repressors that turn genes off or activators that turn genes on and actually make them transcribe more.
Lasseter AP Bio 20 Gene Expression	And a lot of this was discovered through experimentation with the bacteria E. coli.
Lasseter AP Bio 20 Gene Expression	Now E. coli can be good or bad.
Lasseter AP Bio 20 Gene Expression	There's E. coli that makes you sick and E. coli that lives in your gut.
Lasseter AP Bio 20 Gene Expression	But what they did is they would do a lot of experiments with E. coli and exposing it to different growth media and then seeing how the actual E. coli would have reacted.
Lasseter AP Bio 20 Gene Expression	Now E. coli genes of course are prokaryotic genes because E. coli is bacteria.
Lasseter AP Bio 20 Gene Expression	Bacteria are prokaryotes.
Lasseter AP Bio 20 Gene Expression	And they have something special called operons.
Lasseter AP Bio 20 Gene Expression	Now operons are a set of genes transcribed in a single mRNA.
Lasseter AP Bio 20 Gene Expression	So they might be genes that are very close together and they'll all be transcribed at once.
Lasseter AP Bio 20 Gene Expression	Now E. coli cells really don't have operons.

Meiosis

There's only one, two, three and over here one, two, three.

Meiosis

So we technically have haploid cells.

Meiosis

They have one of each kind of chromosome.

Meiosis

Like look at this one with the two lines at the top.

Meiosis

They have one of each kind.

Meiosis

So why do we need to divide again?

Meiosis

Why do we need meiosis number two?

Meiosis

Well, because these chromosomes are duplicated.

Meiosis

Because these chromosomes still have twice as much DNA.

Meiosis

So even though they're haploid with only three chromosomes in each cell, they have their sister chromatids attached.

Meiosis

So we need to divide again and go through a second round of division.

Meiosis

So I'm not really showing prophase two.

Meiosis

Basically it's the same like the nuclear envelope breaks down.

Meiosis

And then we move into metaphase two where the chromosomes are going to move to the middle of the cell.

Meiosis

So basically up here we're looking at meiosis two.

Meiosis

This part is very similar to mitosis.

Meiosis

You'll see here the sister chromatids and anaphase two get pulled apart to opposite sides of the cell.

Meiosis

And then you're going to have your telephase two and cytokinesis where we end up with four genetically different haploid cells.

Meiosis

So remember we started with 2N equals six.

Meiosis

And now look, each of these cells have three.

Meiosis

And if you really look at them, they're all different.

Meiosis

We get four genetically different haploid cells at the end.

Meiosis

And the reason they're different is because of that crossing over, creating recombinant chromosomes, but also the way the homologous pairs lined up in the middle of the cell.

Meiosis

So for example, here let me write on this.

Meiosis

So if I had like here one option and then maybe like the homologous pairs, but very easily couldn't have been where maybe like all of the purple ones are on the left.

Meiosis

And then some of them, all of these, like that would create different combinations of chromosomes in the gametes.

Meiosis

So that independent assortment is another source of variation.

Meiosis

Now in males, the next step would be to add tails and make the cells into sperm.

Meiosis

It goes through spermatogenesis.

Meiosis

Now in females though, you might be thinking, or maybe you're not, but in general for human females, we go through meiosis once a month to produce an egg.

Meiosis

But you just learned that in meiosis, we make four cells, four gametes at the end of meiosis.

Meiosis

However, when a female gets pregnant, she doesn't have quadruplets every time.

Meiosis

And that's because in human females during the meiosis process, one of the cells, like the cytoplasm doesn't divide equally.

Meiosis

And basically one of the cells hogs all of the cytoplasm and we're left with one egg or one ovum and three polar bodies.

Meiosis

And the three polar bodies will actually disintegrate and the parts will get reused.

Meiosis

So we get one egg at the end of meiosis and three polar bodies.

Meiosis

So this is just a visual to kind of show that unequal division of the cytoplasm to make that one mature egg.

Meiosis

All right.

Meiosis

I think that's the end of my discussion on meiosis.

Meiosis

So great job.

Chapter 45 Hormones and the Endocrine System

Alright, so chapter 45 is all about the endocrine system and hormones.

Chapter 45 Hormones and the Endocrine System

Hormones, we've talked about previously, they act as your long-distance regulators, the chemical signals that are secreted into your circulatory system and are able to send out messages throughout the body.

Chapter 45 Hormones and the Endocrine System

They are able to reach all parts of the body through your body fluids, but they can only actually interact with cells, the target cells that have receptors for them.

Chapter 45 Hormones and the Endocrine System

There are two systems that are able to coordinate communication throughout your body, your endocrine system and your nervous system.

Chapter 45 Hormones and the Endocrine System

The endocrine system, the hormones are able to go out throughout the whole body, they're more longer-acting responses, they take a little longer to get going, they impact such processes as reproduction, development, metabolism, growth, behavior, while the nervous system uses high-speed electrical signals along neurons which are able to regulate specific cells.

Chapter 45 Hormones and the Endocrine System

So endocrine signaling is one way information is transmitted.

video_title

transcription

Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)

Okay, so in this video I will compare and contrast primary and secondary succession.

Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)

It's really from my EP bio class.

Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)

It's my final video in community ecology, but if you're just watching this to learn about succession, it should work for you as well.

Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)

So in general, ecological succession is basically like the changing or formation of an ecosystem.

Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)

And we're going to look at primary succession first, and primary succession starts out on bare rock.

Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)

So I took this picture in Volcanoes National Park in Hawaii last year.

Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)

So here is some like, like an active volcano, right?

Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)

So about, I don't know how far, 10 minutes, 15 minute drive from this location, here's the crater of a different volcano, and my family, we walked across it.

Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)

So really when we look at primary succession, it starts out like, how do we start with a brand new volcanic island and then eventually end up with biodiversity?

Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)

Like what are the changes that happen in the plant, in animal communities in that region over the hundreds or thousands of years?

Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)

So here's also a picture of Craters of the Moon National Monument in Idaho.

Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)

Yeah, Idaho.

Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)

And you can see like this is lava rock, but you can see that there's small amounts of plants beginning to grow on it.

Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)

So in succession, we're going to start with a discussion of how do you start on bare rock and then end up with a whole forest of biodiversity.

Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)

So oh, one last example is the Galapagos Islands.

Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)

So the Galapagos Islands are volcanic islands, and you can see from this aerial map, the Valdez are like the peaks of the volcanoes that are now underwater.

Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)

But the Galapagos are volcanic rock, and like here is a picture I took from like a cliff top when I was in Galapagos in 2018, and you can see there's plants and life on these islands, enough to support wildlife.

Primary vs Secondary Succesion (AP Bio Topic 8.5 Community Ecology Part 4)

Here I am with one of the...