Video 2-2: Biomolecules

0:06 Where we left off was a little bit of more concrete knowledge about molecular biology and uh calling it molecular bi biology 101 is kind of a a overstatement that seem that's the US terminology for an introductory course but which you do in in first year before you decide you're a major you start studying without selecting the subject. So these are usually very gentle introductions, but they're a full term long and I won't go that deep. We want to see a little bit though uh what the main uh protagonists are that we're dealing with in bioinformatics.

0:43 Um so it's about the the chemical structures and processes that happen there. uh and uh in particular the first thing I want to look at in a bit more detail is what the different types of molecules or uh substances are that occur at that level. And for this uh I'm going to show you this this video from Amoeba Sisters which has a very whimsical style, but I think their um their content is accurate even though it's a little childish in the kind of drawing style. But uh uh I thought it's nice to show different styles. Maybe um one appeals more to others. They have a huge channel with um top videos about a lot of topics uh some much more in-depth than others. And this one is an overview of just the different molecules that that occur in bionformatics. Um, so let me see if the sound is showing.

1:45 Okay, it looks okay, [music] but maybe you need it a bit louder. >> I want you to think for a moment about your favorite food. What is it? We all have different food preferences, but food is a source of large molecules that are needed for life called biomolecules, also known as macroolelecules, carbohydrates, lipids, proteins, and nucleic acids. In different types of food, you might find higher amounts of these biomolelecules. For example, peanut butter can be high in both proteins and lipids. And while we'll mention examples of foods that contain different biomolelecules in this video, this is not a video on nutrition. This is a video on the classes of biomolelecules and their importance to the structure and function of cells and therefore also to the entire organism because organisms consist of these cells. Before we get into details about the four biomolelecules, we need to talk about one very important vocabulary word. The word monomer. A monomer is a building block. If I had >> I wanted to say with all these videos and all this this kind of biology background, there's lots of terminology that comes up. I had this on the slide.

2:48 I'm not going to quiz you about these in exams for this module. Uh it's also hopeless to not to avoid any kind of jargon. So some of them pop up. You're not supposed to memorize them all, but some uh some will just make it make your life easier following some of the content. The exam material is the the computer science part of all of this. Um, but I think you have more fun exploring the latter parts if you know a little bit about the biology part. Okay. Uh, with that said, >> large substance, the parts that make up that substance are called monomers. With each biomolelecule class, we will mention its monomer if it applies. >> We'll start with the biomolelecule class of carbohydrates. Generally, food sources such as bread, pasta, fruit, and vegetables tend to be high in carbohydrates. The monomer of a carbohydrate, remember that means the building block, is the monossaccharide. One example of a monossaccharide is the sugar glucose. Glucose is a pretty big deal considering it's used in cellular respiration to make ATP, an energy currency. If two monossaccharides such as glucose are combined, you get a disaccharide. For example, put these two glucose sugars together and you get the disaccharide moltos. By the way, a lot of sugars have that ose ending. Glucose, moltos, lactose, sucrose, fructose. I could go on. The ending o can be a carbohydrate clue. If you join a lot of monossaccharides together, that can combine to make a polysaccharide, a big carbohydrate. So, how are carbohydrates important to an organism and the structure and function of its cells?

4:35 Well, plants have cell walls of carbohydrates, specifically a large one known [clears throat] as cellulose. Fungi have cell walls of carbohydrates, too, specifically one known as kiten. Fun fact, that carbohydrate kiten is also what makes up the exoskeleton of insects. We mentioned glucose is used to make ATP. That makes carbohydrates a fast source of energy for cells. So that's a big function for carbs, major energy source that cells can access. That energy can be stored in a polysaccharide form. Remember polysaccharide, it's a big carbohydrate, such as starch for plants or glycogen for animals. Next up, lipids. Lipids include fats and oils. Examples of food sources could include butter or olive oil. This is a seriously diverse group, meaning there are a lot of types of lipids. There are triglycerides, there are phospholipids, there are steroids. These are just some examples. Most, but not all, lipids have building blocks of glycerol and fatty acids. One thing though that lipids generally share.

5:37 Generally, they're hydrophobic or at least contain a significant hydrophobic component. That means lipids or at least a major component of them don't like water. Lipids generally won't dissolve in water. And that's interesting is generally the other biomolelecules will. So, how are lipids important to an organism in the structure and function of its cells? Remember how we said all cells, plant cells, animal cells, all cells have membranes? Well, thank you phospholipids for that phospholipid blayer because that's right, lipids make up cell membrane structure. Lipids have a major function of being a source of long-term energy storage. You remember how we said carbohydrates were a fast source of energy? But when those carbs are used up, lipids have a function as long-term energy storage that an organism can use. Lipids are also very important for different types of insulation. The insulation may involve helping a cell carry an electrical impulse. For example, this myelin sheath made of lipids that can be found on many neurons. Or the insulation may involve temperature regulation, so thermal insulation. For example, the blubber on this adult harp seal is made of lipids, helping it conserve heat. Another cool function about lipids, many lipids act as hormones, which are chemical messengers for many different processes.

6:52 Next up, proteins. Protein food sources include beans, meat, nuts, and eggs. The monomer of a protein is an amino acid. Usually, proteins consist of many amino acids bonded together. There are different types of amino acids. So, how are proteins important to an organism in the structure and function of its cells? Structure- wise, tissue like muscle tissue consist heavily of proteins. Proteins can make up all kinds of other structures, hair or collagen, for example. Proteins can also be found embedded in cell membranes as protein channels. And channels are important to that cell membrane structure with functions of letting certain substances pass through. Proteins can also be receptors, which are critical in cell signaling. So cells can coordinate actions together. Most enzymes are made of proteins. Remember enzymes can build up or break down substances in all kinds of metabolic processes. Antibodies which are made by immune cells in your body are proteins and they are involved in protecting your body. And some critical hormones such as insulin are proteins.

7:55 And when we start talking about genes, genes are made of DNA, but many genes do code for proteins. And that brings us to our last one that includes DNA. Nucleic acids. Nucleic acids include DNA and RNA, which we'll get to in more depth when we get to genetics. Nucleic acids have a monomer called a nucleotide. That's going to be an easy one for you to remember because nucleotide sounds like nucleic acid. By the way, you might wonder, are nucleic acids like DNA and RNA found in my food? And the answer would be yes. Whenever you eat something that came from something living, it actually could still have DNA inside it. For example, when you eat a strawberry, you're actually crunching all the cells that made up that strawberry. And in the nucleus of all those strawberry cells is DNA. Any type of life like plants or animals or fungi or bacteria, they must contain nucleic acids like DNA to direct the cell's activities. How are nucleic acids important for your cells? Well, most of your cells contain all of your genetic information in the form of nucleic acids, DNA and RNA. And this is needed for the coding of your traits, traits involved in structure and various functions. Okay, so we just did a very general tour of four biomolelecules.

9:09 Before we go, I just have to marvel at biomolelecule structure because it's absolutely beautiful. So if I arranged them in the order we did, carbs, lipids, proteins, and nucleic acids, how might we remember the major and most common elements in them? There's a popular pneummonic known as cho cho chomp. Although it's chomp with an N to help me remember the C for carbon, H for hydrogen, O for oxygen, N for nitrogen, and P for carbon. We don't really need >> Does that mean you won't find other elements in the biomolelecules? Of course not. But it's important to understand the arrangement of these elements and biomolelecules because the structure of the arrangement greatly impacts their function. You can learn more in our further reading suggestions in the description. Well, that's it for the MIA sisters and we remind you to stay curious.

10:05 >> Okay. Uh we'll I'll spur the rest of the disclaimers. Um there's a lot more in there than we we need. in particular the fats, the lipids and also the uh carbos carbohydrates are not playing such big a role in in our module. Uh when we come back to proteins and of course nucleic acids. Um in particular uh maybe some of the some of the many uh faces help you remember a bit what the components there were like and uh where they're used.