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Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Most transport vesicles, like the ones going from the ER to the cell membrane, stop off
here first. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | The things inside the vesicles, like proteins, are modified and stored, and later sent to
where they need to go. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | The Golgi apparatus consists of a series of stacks, and there is a cisface, usually facing
the ER, where vesicles arrive, and a transface, where vesicles leave. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | In between, molecules will be modified, with sugars removed or substituted, and generally
prepared for their eventual function. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | This is all done piecewise, as the components move from one cisterna to the next, as each
of these sections has its own set of enzymes. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Before sending things off, products are given molecular tags, like phosphate groups, which
is kind of like an address on a piece of mail to target things for various parts of the
cell, and some vesicles also have certain molecules on their surfaces that can be recognized
by specific organelles, which helps target vesicle delivery. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Another organelle is the lysosome. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | This is a sac containing an environment that is much more acidic than the rest of the cell,
and it holds enzymes that digest large molecules via hydrolysis, which is the breakdown of
a compound due to reaction with a water molecule. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | When food enters a cell through a vesicle by a process called phagocytosis, multiple
vesicles fuse to form a vacuole. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Then a lysosome will fuse with the vacuole and break apart the big chunks of food into
smaller bits. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Lysosomes can also digest damaged organelles that need to be dismantled in a process called
autophagy. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | This allows the cell to maintain optimal functionality. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | There are a few organelles that are not part of the endomembrane system, and a crucial
one is the mitochondrion. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | There are hundreds of mitochondria in most eukaryotic cells, and these are the sites
that carry out cellular respiration, which generates most of the energy the cell needs
to go about its business. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Cellular respiration occurs in three steps, glycolysis, the citric acid cycle, and oxidative
phosphorylation, and you can visit the three-part series in my biochemistry tutorials for more
details on how cellular respiration works. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Beyond this, mitochondria also have two membranes. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | The outer membrane is smooth, but the inner membrane makes many folds called cristae. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | The area in between the two membranes is the intermembrane space, while the innermost part
is called the mitochondrial matrix. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | The matrix contains circular DNA molecules called mitochondrial DNA, and ribosomes, as
well as many of the enzymes that carry out cellular respiration. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | While some of these enzymes can be found in the inner membrane itself. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Another organelle that also has metabolic function is the peroxisome. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | This contains enzymes that perform oxidative processes, which make hydrogen peroxide as
a byproduct. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | These work with mitochondria by breaking down fatty acids into smaller components that are
ready for cellular respiration. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | That's all the organelles, so what else is in there? |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Well, the cellular components are typically tethered to something called the cytoskeleton. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | This is a network of fibers that stretch throughout the cytoplasm of the cell, and keep everything
nice and organized. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | These fibers consist of hollow microtubules made of tubulin dimers, microfilaments made
of two intertwined strands of actin, and intermediate filaments made of coiled keratins. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Beyond organization, these also determine and maintain the shape and structural integrity
of the cell. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Sometimes vesicles utilize motor proteins to deliver their contents to their destinations
by moving along microtubules, like from the ER to the Golgi apparatus, or from the Golgi
apparatus to the cell membrane. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | This is a process that requires ATP to power, and two components move sequentially along
the microtubule in an action that looks a lot like walking. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | In animal cells, microtubules grow outwards from a centrosome, which is located near the
nucleus, and consists of a pair of centrioles, which have microtubules arranged in a ring,
nine sets of three to be exact. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Now that we know a bit about the structure and function of each organelle, we can almost
view the cell as a tiny factory, with each component serving a specific purpose. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | The plasma membrane is like the security guard at the gate, deciding what can go in or out. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Once inside, we see the cytoskeleton, which is the system of girders that provides structure,
and the cytoplasm, which is the factory floor. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | The nucleus is the central office, where the boss sits, giving out orders from the genetic
instructions. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | The endoplasmic reticulum is the assembly line, and the ribosomes are the little factory
workers, building all the proteins the cell needs. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | The Golgi apparatus is the sorting and shipping center. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | The lysosomes are the maintenance and disposal workers, while the mitochondria are the furnace
or power plant that powers the whole show. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | Of course this is just an analogy, none of these organelles have any sentience, but it
illustrates how a cell is much greater than the sum of its parts, a living system with
components that cooperate for survival. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | In addition, after learning a bit about organelle structure and function, endosymbiotic theory
should become quite compelling. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | It is now clear that membrane-enclosed organelles like the nucleus, endoplasmic reticulum, and
Golgi apparatus probably originated from deep folds in the plasma membrane, whereas mitochondria,
as well as chloroplasts, which we will get to next, must have begun as completely separate
organisms, since they have their own DNA and membranes that are different from the cell
membrane. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | All of these diverse structures eventually came to serve as compartments for different
cellular activities, which over an immense time span resulted in things as complex as
the plant and animal cells on earth today. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | We still have more to learn about cells, and we are just scratching the surface of their
complexity. |
Eukaryotic Cells Part 1 Animal Cells and Endosymbiotic Theory | But we've now gone from biomolecules to prokaryotic cells to eukaryotic cells, so
let's learn about another type of eukaryotic cell next. |
Lasseter AP Bio 31 Animal Behavior | Hey guys, welcome to our AP Biology video on animal behavior. |
Lasseter AP Bio 31 Animal Behavior | I want to start you off with this first quote. |
Lasseter AP Bio 31 Animal Behavior | This is actually from a psychologist. |
Lasseter AP Bio 31 Animal Behavior | He says, scientists have reported that elephants grieve their dead, monkeys perceive injustice,
and cockatoos like to dance to the music of the Backstreet Boys. |
Lasseter AP Bio 31 Animal Behavior | And while scientists have actually found that that is true, certain parrots and cockatoos
that have some vocal mimicry behaviors can actually dance to the tempo of a song and
will change their dancing as the tempo changes. |
Lasseter AP Bio 31 Animal Behavior | Parrots and elephants can share this ability, just like humans can, this dancing ability. |
Lasseter AP Bio 31 Animal Behavior | People think, and scientists think, that that's actually because they both have the ability
to mimic vocal sounds, which suggests that dancing ability could be an evolutionary byproduct
of the brain circuitry that allows us and parrots to learn to speak. |
Lasseter AP Bio 31 Animal Behavior | So maybe we can dance because we can talk. |
Lasseter AP Bio 31 Animal Behavior | Pretty interesting though. |
Lasseter AP Bio 31 Animal Behavior | Let's talk about our objectives. |
Lasseter AP Bio 31 Animal Behavior | As an AP student, you should be able to do a couple different things within the realm
of animal behavior. |
Lasseter AP Bio 31 Animal Behavior | Justify scientific claims using evidence to describe how timing and coordination of behavioral
events and organisms are regulated by several mechanisms. |
Lasseter AP Bio 31 Animal Behavior | Connect concepts in and across domains to predict how environmental factors affect responses
to information and change behavior. |
Lasseter AP Bio 31 Animal Behavior | And analyze data that indicate how organisms exchange information in responses to internal
changes and external cues and which can change behavior. |
Lasseter AP Bio 31 Animal Behavior | We're going to talk about some different types of animal behavior today to get the content
out of the way, but we're going to practice some of these different objectives in class
later this week. |
Lasseter AP Bio 31 Animal Behavior | What drives animal behavior? |
Lasseter AP Bio 31 Animal Behavior | Animal behavior is regulated. |
Lasseter AP Bio 31 Animal Behavior | The timing and coordination of behavioral events are regulated, which increases fitness
of individuals and the long-term survival of populations. |
Lasseter AP Bio 31 Animal Behavior | Keep that in mind. |
Lasseter AP Bio 31 Animal Behavior | All of these behaviors, natural selection is going to favor them if, of course, they
increase the fitness. |
Lasseter AP Bio 31 Animal Behavior | And the fitness, again, is our organism's ability to survive and reproduce and pass
on its traits to its offspring. |
Lasseter AP Bio 31 Animal Behavior | Let's talk about timing and coordination and behavior. |
Lasseter AP Bio 31 Animal Behavior | Behavior is regulated by several means. |
Lasseter AP Bio 31 Animal Behavior | Individuals can act on information and communicate it to others. |
Lasseter AP Bio 31 Animal Behavior | For example, there's a species of monkey that can notice a predator in its habitat and then
communicate the presence of that predator to other monkeys within the area through certain
vocal noises. |
Lasseter AP Bio 31 Animal Behavior | There's actually a very interesting radio lab episode of this that I encourage you to
go check out if you're curious. |
Lasseter AP Bio 31 Animal Behavior | I'll link it in the bottom of this video. |
Lasseter AP Bio 31 Animal Behavior | Of course, these responses are vital to natural selection. |
Lasseter AP Bio 31 Animal Behavior | Down here we have some gray snow geese, greater snow geese, which I'll talk about in a second
when I talk about migration. |
Lasseter AP Bio 31 Animal Behavior | Responses can be triggered by environmental cues. |
Lasseter AP Bio 31 Animal Behavior | Some of these responses can be hibernation, migration, estivation. |
Lasseter AP Bio 31 Animal Behavior | Some courtship rituals or other visual displays can be dependent on timing as well. |
Lasseter AP Bio 31 Animal Behavior | Of course, photoperiodism in plants, again, not animal behavior, but we talked about that
already. |
Lasseter AP Bio 31 Animal Behavior | These greater snow geese actually migrate to the tundra in the summer. |
Lasseter AP Bio 31 Animal Behavior | They usually live within five miles of the coast near lakes or rivers. |
Lasseter AP Bio 31 Animal Behavior | During migration, what they do is they follow a very narrow quarter of migration every year
to go to this environment during the summer and winter, which is pretty interesting. |
Lasseter AP Bio 31 Animal Behavior | We'll talk more about migration later in the video. |
Lasseter AP Bio 31 Animal Behavior | Along the lines of communication and cooperative behavior, we can see this within or between
populations and it's going to contribute to the survival of individuals and the survival
of the population. |
Lasseter AP Bio 31 Animal Behavior | For example, we can have a change in a resource availability lead to niche partitioning or
niche partitioning, however you want to pronounce it. |
Lasseter AP Bio 31 Animal Behavior | An example of this that you'll see commonly is the warblers. |
Lasseter AP Bio 31 Animal Behavior | These are types of birds that occupy different strata of the same tree within the same habitat. |
Lasseter AP Bio 31 Animal Behavior | These are actually birds that are going to live within certain strata of the tree. |
Lasseter AP Bio 31 Animal Behavior | They're not in competition for habitat space with other species of warbler. |
Lasseter AP Bio 31 Animal Behavior | They're going to be living within the same tree. |
Lasseter AP Bio 31 Animal Behavior | It's pretty interesting. |
Lasseter AP Bio 31 Animal Behavior | Individuals can act on information and communicate it to others. |
Lasseter AP Bio 31 Animal Behavior | Some innate behaviors that organisms have, these are inherited behaviors. |
Lasseter AP Bio 31 Animal Behavior | Remember that they come through, they're passed down from their parents through their
genes. |
Lasseter AP Bio 31 Animal Behavior | An example would be building a bird's nest or a spider knowing how to spin its web. |
Lasseter AP Bio 31 Animal Behavior | Others can also be learned and these are going to occur through interactions with the environment
and other organisms. |
Lasseter AP Bio 31 Animal Behavior | Animals have sensory organs that can detect and process external information. |
Lasseter AP Bio 31 Animal Behavior | Whether this is the photoreceptors in your eyes that are going to detect the light and
then send signals to your brain which are then going to help us send other signals that
are going to release certain hormones and tell us when to react certain ways and help
us direct our circadian rhythms, etc. |
Lasseter AP Bio 31 Animal Behavior | Or it could be an auditory signal that an animal senses the sound of a predator approaching. |
Lasseter AP Bio 31 Animal Behavior | All of these are very important. |
Lasseter AP Bio 31 Animal Behavior | Here's an example of a learned behavior. |
Lasseter AP Bio 31 Animal Behavior | Behavioral imprinting. |
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