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Bacterial and Plant Cells - 1.1
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About the lecture
In the first mini-lecture, we introduce some eukaryotic and prokaryotic cells in topic 1.1. We learn about some of the microscopic structures within bacterial and plant cells that allow them to carry out their various functions, known as organelles. We investigate the cell membrane, cell wall, the nucleus (or lack thereof in bacteria), ribosomes, mitochondria, vacuole, chloroplasts and cytoplasm. In addition we look at some of the extracellular structures bacteria can possess such as a slime coat and tail-like structures called flagella.
About the lecturer
Dr Matthew Ivory is a Lecturer at Cardiff University in the School of Pharmacy and Pharmaceutical Sciences (2016-present). His key expertise is in ex vivo human skin organ culture and histology, human skin immune cell extraction and culture, flow cytometry and pharmaceutical formulation, and his research interests are in the delivery of vaccines and therapeutics into the skin. In addition to this, he is also a qualified pharmacist.
Hi.
00:00:05My name is Dr Matt Ivory and one of the
00:00:06lecturers in the School of Pharmacy and Pharmaceutical Sciences.
00:00:08In the series of talks today,
00:00:11we are going to look at cells so we'll look at pro carry out IQ cells bacteria,
00:00:13and we'll look at the eukaryotic cells of plants and animals and talk
00:00:18about how the cells and structures within them are adapted for their purposes.
00:00:22We also have a look at microscopy,
00:00:27how it's developed and how it can be used to study cells and their structures.
00:00:28So in this first talk we will have a look at the
00:00:33differences and similarities between pro carry out IQ and eukaryotic cells.
00:00:37So all living things on Earth are made up of cells.
00:00:44Some organisms contain just one cell.
00:00:47They're called single celled organisms, or uni cellular,
00:00:49while others contain many cells.
00:00:53So it might be, too, might be more might be billions, maybe trillions,
00:00:55and these are called multi cellular organisms.
00:00:58So, for example, us as humans have on average, over 30 trillion cells within our body
00:01:01and the cells of all the organisms of the
00:01:08world can be classified into one of two groups.
00:01:11So there are eukaryotic cells,
00:01:13and these are distinguishable by their genetic material,
00:01:17which is contained within a membrane bound nucleus.
00:01:20And there are also pro carry attic cells who
00:01:24have their genetic material not in a nucleus,
00:01:26so it just floats free in the cytoplasm of the cell.
00:01:29So organisms composed of eukaryotic cells so with their genetic
00:01:34material inside of a nucleus are called you carry outs,
00:01:37and those composed of pro carry attic cells are called pro carry.
00:01:41It's so eukaryotic cells tend to be larger
00:01:45and more complex than pro Kerry attic cells,
00:01:48and both plants and animals are made up of eukaryotic cells.
00:01:51Poke Marriotts includes bacteria who have smaller and much less complex cells,
00:01:57and both these cell types are both eukaryotic cells and pro carry
00:02:03attic cells have a range of sub cellular structures called organelles,
00:02:06and these allow the cell to perform all of the different processes
00:02:11that it needs to produce energy to survive to excrete waste.
00:02:14Everything that our cell does to stay alive,
00:02:18to grow to reproduce is performed by these organelles
00:02:21and the types of organelles than the number of them within.
00:02:25Each cell will vary slightly differently
00:02:29between animal plant and bacterial cells.
00:02:31So if we start with the smallest and most simple cells, so we start with pro carry its.
00:02:36So if we look at the organelles that are contained within a bacterial cell,
00:02:42so on their outer surface, bacteria will have a cell membrane,
00:02:47and this acts kind of like the skin of the bacterial cell,
00:02:52so it keeps everything in that the bacteria wants to keep in,
00:02:55and it also keeps the external environment out,
00:02:59And this allows the bacteria to have some control over what goes on inside
00:03:03it and control the different levels of substances within it versus the outside.
00:03:07So within the bacteria is a watery gel like substance that's called the cytoplasm,
00:03:13and this is where all of the important chemical reactions inside the Celica
00:03:19and outside of the cell membrane so some bacteria just have a cell membrane.
00:03:23Others will have a bacterial cell wall outside of their cell
00:03:28membrane that is tough and provides support to the cell.
00:03:32And some bacteria will have another layer as well called slime coat,
00:03:36which also provides protection to the bacterial cell
00:03:41and helps it stick to other cells into services.
00:03:44So some bacteria may have a structure called a flagellum,
00:03:46and if they have more than one,
00:03:51then it's flat. Gela, So flagellum is singular.
00:03:53Flotilla is plural,
00:03:56and these are long hair, like a whip like structures that extend from the cell.
00:03:58And they can be spun by the bacterial cell
00:04:04to allow the cell to move within its environment.
00:04:07So if a bacteria just stayed in place or was at the mercy of the elements around it,
00:04:09the movement of water and its environment,
00:04:15let's say it wouldn't have any control over whether it
00:04:17was able to move towards food or away from danger.
00:04:20So by having these flu, Gela
00:04:23bacterial cells can
00:04:25move towards or away from stimuli.
00:04:27This is really important to allow them to survive in order
00:04:30to be able to reproduce and keep their species going.
00:04:33So bacterial cells contain genetic material,
00:04:36and this is contained in chromosomal DNA.
00:04:40So as they are pro carry attic sells,
00:04:44this genetic material isn't contained within a nucleus.
00:04:47Instead,
00:04:50it's floating free in the cytoplasm within the cell of a pro carry attic bacteria,
00:04:51and this chromosome DNA contains the instructions needed to produce things
00:04:57like proteins that help the bacteria undergo all of its normal processes
00:05:02and allowing it to make copies of itself when it undergoes a sexual reproduction
00:05:08as well as chromosomal DNA in the bacterial cell will often contain plasmid DNA.
00:05:14And so plasma Deanna are much smaller loops of genetic material,
00:05:20so little circles of Vienna
00:05:25and these can be used by the bacteria
00:05:27so they get expressed to develop new characteristics.
00:05:29Things like antibiotic resistance
00:05:32and one of the defining features of plasmids
00:05:35is that they can be passed between bacterial
00:05:37cells so it gives bacteria an opportunity to
00:05:39pass on things like antibiotic resistance genes,
00:05:42which helped them to survive and gives the
00:05:45whole species a better chance of survival,
00:05:48Um, and producing more copies.
00:05:50So there are also organelles called ribosomes within bacterial cells,
00:05:54and these are useful machinery for building proteins.
00:05:59Um, and so lots of useful molecules in the bacterial cell are made of proteins,
00:06:03so enzymes that catalyse biological reactions.
00:06:08Parts of the flu Gela are formed of protein, and so by using these ribosomes,
00:06:12they can build all the bits and pieces that you need to form all these useful tools.
00:06:17The chromosomes of bacterial cells are
00:06:22slightly smaller than Eukaryotic ribosomes.
00:06:25But they do the same job, so they're just structurally a little bit different.
00:06:28But the function is the same to produce proteins
00:06:32so moving up in size and complexity now to plant cells so plant cells have a nucleus.
00:06:36And so, unlike bacterial cells,
00:06:44where that nuclear material that Vienna is floating free in the cytoplasm,
00:06:46the genetic material in a plant cell,
00:06:51the chromosomal DNA is contained within the membrane bound nucleus.
00:06:54So a plant cell has a cell membrane on its outside like a bacterial cell did.
00:06:59But it also has a nuclear membrane inside, so two sets of membranes.
00:07:04And this nuclear membrane is important because it keeps the
00:07:10nuclear material the D N A in one place,
00:07:13and it also helps to protect it from damage.
00:07:16So I've mentioned the cell membrane so that allows plant cells
00:07:19to control the entry and exit of substances from the cell
00:07:23and outside of the cell membrane. Plant cell will have a cell wall,
00:07:27and this will similar to bacterial cell, provides support and strengthen the cell.
00:07:31But unlike bacterial cell walls, it'll be made out of cellulose,
00:07:36so bacterial cell walls are made out of different materials.
00:07:40Plant cell walls are all made out of cellulose,
00:07:43so as well as bacterial cells.
00:07:47Plant cells contain ribosomes, so they are bigger, as I said,
00:07:49because they are eukaryotic ribosomes,
00:07:52and they will perform the same function, though expressing the code with Indiana
00:07:56and turning it into peptides and proteins.
00:08:01So plant cells also contain chloroplasts,
00:08:07and these are organelles that contain chlorophyll
00:08:10and chlorophyll is green pigment that absorbs
00:08:13light and allows photosynthesis to occur.
00:08:15And that's where the plant combines carbon dioxide water and
00:08:18the energy from light to make glucose and oxygen.
00:08:23And this is covered in much more detail. In the lecture on photosynthesis,
00:08:26plant cells will also contain mitochondria,
00:08:30and you may have heard the old phrase the powerhouse of the cell.
00:08:33And that is exactly what mitochondria as organelles.
00:08:36So these are the structures where Arabic respiration takes place,
00:08:39and so they break down energy rich molecules like glucose,
00:08:44and they provide the energy for cellular processes so
00:08:48you can think of them as little coal burners
00:08:51that create the energy that is required by the cell to run.
00:08:54And then last but not least,
00:08:59we have a vacuole So this is a large storage structure in the centre of a plant cell,
00:09:01and it's used to store cell sap, which is a weak solution of sugar and salt in water,
00:09:07and the combination of the outward pressure from
00:09:14the vacuole in the middle of the cell
00:09:17and the inward strengthening of the cell wall.
00:09:19That stiffness that exists within the cell wall creates rigidity in plant cells.
00:09:22And this is what land plants rely on to to stay upright, to grow upwards
00:09:27and helps them stand up when they're well watered.
00:09:32And you may have noticed when a plant is short of water that it
00:09:35will lose this rigidity and the whole plant groups because it can't support itself.
00:09:39
Cite this Lecture
APA style
Ivory, M. (2022, October 31). Module 1: Cells as the Basis of Life - Bacterial and Plant Cells - 1.1 [Video]. MASSOLIT. https://massolit.io/options/module-1-cells-as-the-basis-of-life?auth=0&lesson=10237&option=15848&type=lesson
MLA style
Ivory, M. "Module 1: Cells as the Basis of Life – Bacterial and Plant Cells - 1.1." MASSOLIT, uploaded by MASSOLIT, 31 Oct 2022, https://massolit.io/options/module-1-cells-as-the-basis-of-life?auth=0&lesson=10237&option=15848&type=lesson