1 00:00:00,660 --> 00:00:01,860 [Instructor] Hi, everybody, 2 00:00:01,860 --> 00:00:06,360 and welcome to DPT 406, Exercise Science. 3 00:00:06,360 --> 00:00:09,933 And today's talk is about bioenergetics. 4 00:00:14,700 --> 00:00:19,200 So if you think of yourself as a living organism, 5 00:00:19,200 --> 00:00:20,250 which you are, 6 00:00:20,250 --> 00:00:24,480 you have the ability to produce, store, and transfer energy. 7 00:00:24,480 --> 00:00:27,390 And basically that's how we survive. 8 00:00:27,390 --> 00:00:31,323 that's how we use foods for fuel for our body. 9 00:00:32,160 --> 00:00:34,650 Energy originates as life from the sun 10 00:00:34,650 --> 00:00:37,350 and it's converted into energy forms 11 00:00:37,350 --> 00:00:39,420 that we utilize for our fuel, 12 00:00:39,420 --> 00:00:42,420 such as carbohydrates, proteins, and fats. 13 00:00:42,420 --> 00:00:44,340 And we get these carbs, proteins, and fats 14 00:00:44,340 --> 00:00:46,950 from animals and plants. 15 00:00:46,950 --> 00:00:50,370 We consume these energy sources, 16 00:00:50,370 --> 00:00:53,340 and through our digestive process, 17 00:00:53,340 --> 00:00:54,900 we break them down 18 00:00:54,900 --> 00:00:59,250 and then we break down these substrates 19 00:00:59,250 --> 00:01:01,680 and our body absorbs them, 20 00:01:01,680 --> 00:01:04,960 assimilating them into our system 21 00:01:05,880 --> 00:01:07,083 for fuel. 22 00:01:09,630 --> 00:01:14,070 We can use this fuel immediately 23 00:01:14,070 --> 00:01:18,480 if we're working out or if our system's been depleted, 24 00:01:18,480 --> 00:01:21,360 or we can store it for later use. 25 00:01:21,360 --> 00:01:23,580 And the form of energy used by our body 26 00:01:23,580 --> 00:01:26,887 is called adenosine triphosphate or ATP. 27 00:01:33,480 --> 00:01:36,450 Some terms that you need to know, 28 00:01:36,450 --> 00:01:40,920 metabolism is the total of all cellular reactions. 29 00:01:40,920 --> 00:01:44,550 So you've probably heard this in regards to yourself 30 00:01:44,550 --> 00:01:46,920 or someone else that they have a slow metabolism 31 00:01:46,920 --> 00:01:48,750 or a fast metabolism. 32 00:01:48,750 --> 00:01:51,030 Anyway, the metabolism is the process 33 00:01:51,030 --> 00:01:53,100 of this cellular reactions 34 00:01:53,100 --> 00:01:58,080 of ingesting and not digesting food, 35 00:01:58,080 --> 00:02:02,340 and then breaking it down into usable fuel sources. 36 00:02:02,340 --> 00:02:06,870 So technically, it's inclusive of the chemical pathways 37 00:02:06,870 --> 00:02:09,570 that result in the synthesis of molecules, 38 00:02:09,570 --> 00:02:11,310 these anabolic reactions, 39 00:02:11,310 --> 00:02:13,703 and we'll talk about some of these pathways in a bit. 40 00:02:15,510 --> 00:02:18,840 So the synthesis is anabolic, building up, 41 00:02:18,840 --> 00:02:21,840 and the breakdown is catabolic. 42 00:02:21,840 --> 00:02:26,840 And bioenergetics is the chemical pathways in the body 43 00:02:28,710 --> 00:02:31,200 that the body uses to convert food 44 00:02:31,200 --> 00:02:34,683 into a biological, usable form of energy. 45 00:02:37,560 --> 00:02:40,680 In our body, there are four different elements 46 00:02:40,680 --> 00:02:45,680 that compose over 90% of us as living beings, 47 00:02:45,780 --> 00:02:50,490 and the majority is oxygen at 65%, 48 00:02:50,490 --> 00:02:55,200 carbon at 18%, hydrogen at 10%, and nitrogen at 3%. 49 00:02:55,200 --> 00:02:56,760 There's also additional elements 50 00:02:56,760 --> 00:02:59,310 that are found in small amounts in our body, 51 00:02:59,310 --> 00:03:01,740 so, like, sodium or iron, zinc, potassium, 52 00:03:01,740 --> 00:03:03,900 magnesium, chloride, and calcium. 53 00:03:03,900 --> 00:03:08,280 And we do need these to have our bodies run efficiently. 54 00:03:08,280 --> 00:03:12,390 These elements are linked by chemical bonds 55 00:03:12,390 --> 00:03:14,793 to form molecules or compounds. 56 00:03:16,380 --> 00:03:19,620 Compounds with carbon are organic, 57 00:03:19,620 --> 00:03:23,433 and compounds without carbon are non-organic. 58 00:03:26,880 --> 00:03:30,420 Again, bioenergetics is the transfer of energy 59 00:03:30,420 --> 00:03:34,830 from the foods we eat into a biologically usable form. 60 00:03:34,830 --> 00:03:38,580 And this process converts chemical energy 61 00:03:38,580 --> 00:03:40,320 to mechanical energy. 62 00:03:40,320 --> 00:03:41,910 And there's a series 63 00:03:41,910 --> 00:03:45,840 of very well-controlled chemical reactions that occur. 64 00:03:45,840 --> 00:03:48,690 So an enderdonic reaction 65 00:03:48,690 --> 00:03:52,230 or sometimes called an endothermic reaction, 66 00:03:52,230 --> 00:03:55,440 requires energy to be added to the reactant 67 00:03:55,440 --> 00:03:57,120 before the reactant can proceed. 68 00:03:57,120 --> 00:03:59,310 So nothing's gonna happen 69 00:03:59,310 --> 00:04:02,190 with an enderdonic or endothermic reaction 70 00:04:02,190 --> 00:04:07,170 until energy or ATP is utilized 71 00:04:07,170 --> 00:04:09,123 to cause that reactant to start. 72 00:04:10,320 --> 00:04:11,610 So it's kinda like putting gas in the car. 73 00:04:11,610 --> 00:04:13,890 The car won't run unless you put some gas in, 74 00:04:13,890 --> 00:04:15,213 and then it can run. 75 00:04:16,240 --> 00:04:21,180 Exergonic reactions or exothermic reactions, 76 00:04:21,180 --> 00:04:24,930 same thing, after these reactions occur, 77 00:04:24,930 --> 00:04:27,900 they give off energy as a result of a chemical process. 78 00:04:27,900 --> 00:04:32,370 So exergonic does not require energy to be added initially. 79 00:04:32,370 --> 00:04:36,420 So an exergonic reaction 80 00:04:36,420 --> 00:04:38,733 doesn't use energy and produces energy. 81 00:04:41,550 --> 00:04:43,500 Five key elements of bioenergetics 82 00:04:43,500 --> 00:04:46,500 are coupled reactions, enzymes, 83 00:04:46,500 --> 00:04:49,500 oxidation-reduction reactions, 84 00:04:49,500 --> 00:04:52,470 understanding substrates and products, 85 00:04:52,470 --> 00:04:53,940 and shuttles and transporters. 86 00:04:53,940 --> 00:04:58,940 So all of these elements are required to produce energy. 87 00:05:00,270 --> 00:05:02,760 So a coupled reaction is a reaction 88 00:05:02,760 --> 00:05:04,690 that releases energy 89 00:05:06,060 --> 00:05:08,613 required for another reaction to occur. 90 00:05:10,680 --> 00:05:12,470 And as we said on the prior slide, 91 00:05:12,470 --> 00:05:15,660 an exergonic reaction releases energy. 92 00:05:15,660 --> 00:05:17,110 And so 93 00:05:18,060 --> 00:05:21,240 this reaction will produce ATP 94 00:05:21,240 --> 00:05:25,110 for an endergonic reaction to occur. 95 00:05:25,110 --> 00:05:29,250 So sometimes you need the energy-producing reaction 96 00:05:29,250 --> 00:05:31,830 to fuel the next reaction 97 00:05:31,830 --> 00:05:34,103 where you're gonna get a bigger bang for your buck. 98 00:05:35,220 --> 00:05:37,680 Enzymes are the catalysts that enhance 99 00:05:37,680 --> 00:05:39,150 the rate of chemical reactions. 100 00:05:39,150 --> 00:05:42,543 So we need these enzymes to kind of get reactions, 101 00:05:43,980 --> 00:05:45,960 to move them along or speed them up. 102 00:05:45,960 --> 00:05:48,813 They facilitate the reaction. 103 00:05:50,130 --> 00:05:52,920 Oxidation and reduction reactions, 104 00:05:52,920 --> 00:05:55,410 we'll talk a little bit more about this 105 00:05:55,410 --> 00:05:56,760 on an upcoming slide, 106 00:05:56,760 --> 00:05:59,373 but these reactions always occur together. 107 00:06:00,480 --> 00:06:05,283 Substrates are molecules that are acted upon by enzymes, 108 00:06:07,170 --> 00:06:09,630 and products are molecules 109 00:06:09,630 --> 00:06:12,573 that are manufactured from the substrates. 110 00:06:14,640 --> 00:06:19,230 There are also different shuttles or transporters 111 00:06:19,230 --> 00:06:24,230 that assist molecules and the molecular movement 112 00:06:24,450 --> 00:06:29,450 across surfaces or membranes from different substrates. 113 00:06:32,190 --> 00:06:34,320 So just some terms, and the book has all of these 114 00:06:34,320 --> 00:06:37,263 and has some pictures too to help show. 115 00:06:38,190 --> 00:06:40,770 But here as an example from the book, 116 00:06:40,770 --> 00:06:42,750 about a coupled reaction. 117 00:06:42,750 --> 00:06:45,090 So as we talked about earlier, 118 00:06:45,090 --> 00:06:46,800 these coupled reactions occur, 119 00:06:46,800 --> 00:06:51,800 so energy is released from one exergonic reaction 120 00:06:52,950 --> 00:06:55,893 to fuel another endergonic reaction. 121 00:07:00,810 --> 00:07:02,550 Oxidation-reduction reaction. 122 00:07:02,550 --> 00:07:06,390 So oxidation is when an electron 123 00:07:06,390 --> 00:07:09,120 is removed from an atom or a molecule, 124 00:07:09,120 --> 00:07:12,620 and reduction is the addition of an electron 125 00:07:12,620 --> 00:07:14,430 to an atom or molecule. 126 00:07:14,430 --> 00:07:17,160 And oxidation and reduction are always coupled reactions, 127 00:07:17,160 --> 00:07:19,390 because a molecule can't be oxidized 128 00:07:20,550 --> 00:07:22,200 or removed an electron 129 00:07:22,200 --> 00:07:25,350 unless it can donate that electron to another atom. 130 00:07:25,350 --> 00:07:28,980 So that reaction won't occur unless there's a place 131 00:07:28,980 --> 00:07:30,900 where that electron can go to. 132 00:07:30,900 --> 00:07:32,253 So basic chemistry. 133 00:07:37,020 --> 00:07:40,740 So this picture is basically showing a bioenergetic process 134 00:07:40,740 --> 00:07:44,617 of nicotinamide adenine dinucleotide turning into NADH, 135 00:07:50,490 --> 00:07:53,490 so having a hydrogen molecule added. 136 00:07:53,490 --> 00:07:56,790 And to do this, 137 00:07:56,790 --> 00:08:00,213 there will be a reductive process. 138 00:08:01,320 --> 00:08:04,380 So NAD is just sitting here 139 00:08:04,380 --> 00:08:09,000 and when it reacts with two hydrogen atoms, 140 00:08:09,000 --> 00:08:14,000 it's going to then receive two electrons. 141 00:08:14,190 --> 00:08:18,060 So remember the oxidative state 142 00:08:18,060 --> 00:08:21,630 is where it can give up electrons, 143 00:08:21,630 --> 00:08:25,473 and the reducted state is when it's receiving electrons. 144 00:08:34,080 --> 00:08:35,013 Whoops. 145 00:08:36,000 --> 00:08:40,260 Okay, so enzymes are, again, technical definition, 146 00:08:40,260 --> 00:08:42,750 proteins that regulate the metabolic pathways. 147 00:08:42,750 --> 00:08:44,010 So as I said, 148 00:08:44,010 --> 00:08:47,250 they control the rate and the speed of a reaction. 149 00:08:47,250 --> 00:08:51,273 So enzymes are really necessary to get reactions going. 150 00:08:52,530 --> 00:08:55,050 They lower the energy of activation 151 00:08:55,050 --> 00:08:58,050 or the energy required to achieve the reaction. 152 00:08:58,050 --> 00:09:01,470 And so having enzymes present increases the probability 153 00:09:01,470 --> 00:09:03,720 that the reaction is going to occur. 154 00:09:03,720 --> 00:09:07,980 So this is a little schematic that kind of shows that. 155 00:09:07,980 --> 00:09:11,280 So you wanna have this reaction occur. 156 00:09:11,280 --> 00:09:13,890 However, there's this barrier here. 157 00:09:13,890 --> 00:09:17,460 Perhaps it's a cell membrane 158 00:09:17,460 --> 00:09:20,730 and there's energy that needs to be utilized 159 00:09:20,730 --> 00:09:23,700 to get this reactant in. 160 00:09:23,700 --> 00:09:26,433 But with an enzyme present, 161 00:09:27,270 --> 00:09:30,570 the energy of activation is lower 162 00:09:30,570 --> 00:09:33,690 and so the reaction has a higher likelihood 163 00:09:33,690 --> 00:09:35,403 that it's going to happen. 164 00:09:39,300 --> 00:09:44,300 So in further breaking down the processes, 165 00:09:45,330 --> 00:09:49,980 we're going to be looking particularly at molecules 166 00:09:49,980 --> 00:09:53,310 that are acted upon by these enzymes. 167 00:09:53,310 --> 00:09:56,430 And so those are termed substrates. 168 00:09:56,430 --> 00:09:58,590 So in the prior picture, 169 00:09:58,590 --> 00:10:03,590 we were looking at a reaction that was utilizing enzymes. 170 00:10:04,410 --> 00:10:06,393 So for those enzymes to work, 171 00:10:10,570 --> 00:10:13,750 they need to act on a molecule or a substrate. 172 00:10:14,640 --> 00:10:19,640 So you can see here, here's a little enzyme molecule 173 00:10:19,710 --> 00:10:22,710 and it's going to attach itself 174 00:10:22,710 --> 00:10:24,930 to these two substrate molecules, 175 00:10:24,930 --> 00:10:28,080 and it becomes a new complex, right here. 176 00:10:28,080 --> 00:10:33,080 So this is a product of the enzyme and the substrates. 177 00:10:36,270 --> 00:10:37,950 It's like a lock and a key. 178 00:10:37,950 --> 00:10:40,560 And so these two substrates are gonna fit 179 00:10:40,560 --> 00:10:43,140 into the shape of the enzyme's active site, 180 00:10:43,140 --> 00:10:47,523 so it's very site specific, forming this product. 181 00:10:48,510 --> 00:10:51,780 The enzyme then, it catalyzes the chemical reaction 182 00:10:51,780 --> 00:10:55,233 to form this new product here. 183 00:10:58,680 --> 00:11:00,990 These reactions 184 00:11:00,990 --> 00:11:03,930 can produce a product, 185 00:11:03,930 --> 00:11:05,910 but then they can be broken back down 186 00:11:05,910 --> 00:11:08,490 into their substrate components 187 00:11:08,490 --> 00:11:10,950 or produce a new product. 188 00:11:10,950 --> 00:11:15,900 So here, were two substrates alone and enzyme acts on them, 189 00:11:15,900 --> 00:11:18,330 it forms a new product, 190 00:11:18,330 --> 00:11:20,730 and then the enzyme can break away 191 00:11:20,730 --> 00:11:24,150 and it has this resultant new product 192 00:11:24,150 --> 00:11:27,660 that's different than the sum of the substrate parts, 193 00:11:27,660 --> 00:11:28,893 if that makes sense. 194 00:11:32,010 --> 00:11:34,473 Enzymes are released from our body. 195 00:11:35,580 --> 00:11:39,600 They're controlled by different processes. 196 00:11:39,600 --> 00:11:42,150 When there's cell damage or disease, 197 00:11:42,150 --> 00:11:43,860 enzymes are released to kind of start 198 00:11:43,860 --> 00:11:46,833 the inflammatory process or the cleanup process. 199 00:11:49,440 --> 00:11:54,210 Often, some laboratory tests will be used 200 00:11:54,210 --> 00:11:56,640 to identify whether enzymes are present or not. 201 00:11:56,640 --> 00:11:59,193 So when someone has a heart attack, for example, 202 00:12:00,420 --> 00:12:03,750 these cardiac enzymes will be released into the system 203 00:12:03,750 --> 00:12:06,210 because there's been a damage to the system. 204 00:12:06,210 --> 00:12:08,520 And if those enzymes are found, 205 00:12:08,520 --> 00:12:10,320 it's indicative that there was in fact, 206 00:12:10,320 --> 00:12:12,540 myocardial infarction. 207 00:12:12,540 --> 00:12:16,293 Enzymes all end in an ase. 208 00:12:17,520 --> 00:12:21,720 So dehydrogenase is an enzyme that removes hydrogen. 209 00:12:21,720 --> 00:12:25,920 So anytime you see an ase at the end of a word, 210 00:12:25,920 --> 00:12:27,720 it is an enzyme. 211 00:12:27,720 --> 00:12:31,110 Enzyme activity is affected by temperature, 212 00:12:31,110 --> 00:12:33,750 so hot and cold, as well as pH levels, 213 00:12:33,750 --> 00:12:36,780 so something's more acidic or alkaline, 214 00:12:36,780 --> 00:12:39,750 and that can either the temperature and acidity, 215 00:12:39,750 --> 00:12:44,240 or pH level can either facilitate or restrict a reaction. 216 00:12:47,670 --> 00:12:49,500 So here's just a schematic, 217 00:12:49,500 --> 00:12:52,530 looking at how body temperature 218 00:12:52,530 --> 00:12:55,800 can affect enzymatic activity. 219 00:12:55,800 --> 00:12:57,760 So the optimal range 220 00:12:58,800 --> 00:13:01,360 is right at about 221 00:13:02,940 --> 00:13:04,623 body temperature. 222 00:13:05,910 --> 00:13:08,160 So anything too hot, 223 00:13:08,160 --> 00:13:10,290 the enzymatic activities going to decrease, 224 00:13:10,290 --> 00:13:12,840 anything too cold, it's going to decrease. 225 00:13:12,840 --> 00:13:16,320 Same thing, the optimal range for the pH 226 00:13:16,320 --> 00:13:19,260 is right around that neutral level, 227 00:13:19,260 --> 00:13:21,447 so, like, a 7.4. 228 00:13:21,447 --> 00:13:24,993 And so anything greater than an 8, 229 00:13:25,860 --> 00:13:28,150 if it's too 230 00:13:30,120 --> 00:13:33,390 alkaline or too acidic, the other direction, 231 00:13:33,390 --> 00:13:38,390 then the enzymatic activity will not be optimal. 232 00:13:38,970 --> 00:13:42,090 So we just talked about some different terminology 233 00:13:42,090 --> 00:13:47,090 necessary to understand bioenergetic processes. 234 00:13:47,970 --> 00:13:49,890 And now let's talk a little bit about the fuels 235 00:13:49,890 --> 00:13:52,323 that are used within these processes. 236 00:13:53,250 --> 00:13:57,840 For any type of physical activity or just existence alone, 237 00:13:57,840 --> 00:13:59,400 our body needs fuel. 238 00:13:59,400 --> 00:14:01,890 And our body uses carbohydrates, fats, 239 00:14:01,890 --> 00:14:03,750 and protein nutrients. 240 00:14:03,750 --> 00:14:07,440 And so these nutrients 241 00:14:07,440 --> 00:14:08,970 provide the energy needed 242 00:14:08,970 --> 00:14:10,920 to maintain all of our cellular functions, 243 00:14:10,920 --> 00:14:12,450 both at rest and during exercise. 244 00:14:12,450 --> 00:14:14,250 So even when you're sitting doing nothing, 245 00:14:14,250 --> 00:14:18,930 your body needs fuel just to maintain 246 00:14:18,930 --> 00:14:21,510 the homeostasis of your body, 247 00:14:21,510 --> 00:14:23,880 your basal metabolic rate 248 00:14:23,880 --> 00:14:25,800 or your resting metabolic rate. 249 00:14:25,800 --> 00:14:29,040 You know, your digestive processes, your heart. 250 00:14:29,040 --> 00:14:30,570 So all of that needs fuel 251 00:14:30,570 --> 00:14:31,980 even when you're not moving. 252 00:14:31,980 --> 00:14:34,110 During exercise or physical activity, 253 00:14:34,110 --> 00:14:36,690 you need even more fuel. 254 00:14:36,690 --> 00:14:39,300 And the primary nutrients for this fuel 255 00:14:39,300 --> 00:14:41,310 are fats and carbohydrates. 256 00:14:41,310 --> 00:14:44,490 Proteins contribute a small amount to the total energy use, 257 00:14:44,490 --> 00:14:46,260 it's mostly fats and carbs. 258 00:14:46,260 --> 00:14:48,780 Carbohydrates, as they're sounding, 259 00:14:48,780 --> 00:14:52,410 are composed of carbon, hydrogen, and oxygen atoms, 260 00:14:52,410 --> 00:14:55,983 and stored carbs within our muscle, or tissues, 261 00:14:56,850 --> 00:14:57,780 or in our blood, 262 00:14:57,780 --> 00:15:00,840 provide the body with a rapid available form of energy. 263 00:15:00,840 --> 00:15:03,873 So carbs are kind of the first thing that we can use. 264 00:15:04,800 --> 00:15:07,140 One gram of carbohydrate 265 00:15:07,140 --> 00:15:12,140 yields about 4 kilo calories of energy or kcals. 266 00:15:12,570 --> 00:15:15,270 It's kind of the equivalent of a calorie. 267 00:15:15,270 --> 00:15:18,960 So this'll be important later on 268 00:15:18,960 --> 00:15:23,960 when we get into determining how much fuel or carbs 269 00:15:24,600 --> 00:15:26,220 someone needs to eat 270 00:15:26,220 --> 00:15:30,930 to do a certain amount of physical activity or output, 271 00:15:30,930 --> 00:15:33,480 or how many carbs they need to not eat 272 00:15:33,480 --> 00:15:35,130 if they're trying to lose weight. 273 00:15:36,390 --> 00:15:38,820 So 1 gram of carbohydrate yields 274 00:15:38,820 --> 00:15:40,773 approximately 4 kcals. 275 00:15:42,000 --> 00:15:47,000 Fats, carbon and oxygen ratio in the fats 276 00:15:47,250 --> 00:15:48,960 is greater than in the carbohydrate. 277 00:15:48,960 --> 00:15:50,590 So there's more energy 278 00:15:53,730 --> 00:15:55,470 in a fat nutrient. 279 00:15:55,470 --> 00:16:00,470 And so 1 gram of fat contains about 9 kcals of energy. 280 00:16:01,200 --> 00:16:05,523 And fatty acids are the primary type of fat used by muscles, 281 00:16:06,420 --> 00:16:09,510 you know, kind of for long endurance-type activities. 282 00:16:09,510 --> 00:16:11,100 Proteins on the other hand, 283 00:16:11,100 --> 00:16:15,930 1 gram contains about 4 kilo cals of energy as well, 284 00:16:15,930 --> 00:16:20,930 but they are not the first choice of fuel 285 00:16:21,240 --> 00:16:22,713 to be used in our body. 286 00:16:26,580 --> 00:16:29,463 So a calorie, just a technical definition, 287 00:16:31,110 --> 00:16:35,850 is the amount of heat or the quantity of heat 288 00:16:35,850 --> 00:16:39,900 required to raise the temperature of 1 kilogram of water 289 00:16:39,900 --> 00:16:42,120 by 1 degree Celsius, 290 00:16:42,120 --> 00:16:47,120 or from 58 degrees Fahrenheit to 60 degrees Fahrenheit. 291 00:16:48,600 --> 00:16:53,600 And so the amount of work that is performed by a human 292 00:16:55,380 --> 00:16:58,350 can be quantified through calories. 293 00:16:58,350 --> 00:17:00,180 And so these calories are abbreviated 294 00:17:00,180 --> 00:17:02,880 as I mentioned, on the other slide, as a kcal. 295 00:17:02,880 --> 00:17:04,360 Or they can also be 296 00:17:06,960 --> 00:17:08,877 defined by kilojoules as well, 297 00:17:08,877 --> 00:17:11,130 but kcals is more familiar or calories, 298 00:17:11,130 --> 00:17:13,950 and you see it on all of our food labels now. 299 00:17:13,950 --> 00:17:18,900 How many calories are embedded 300 00:17:18,900 --> 00:17:20,373 in that fuel if you eat them. 301 00:17:26,340 --> 00:17:29,430 So for our bodies to be able to use 302 00:17:29,430 --> 00:17:33,300 our food fuel sources of carbs and fats, 303 00:17:33,300 --> 00:17:37,440 we need energy to break that down. 304 00:17:37,440 --> 00:17:40,980 And the immediate source of energy for a muscle contraction 305 00:17:40,980 --> 00:17:43,440 is the high-energy phosphate compound 306 00:17:43,440 --> 00:17:48,070 of adenosine triphosphate or ATP and it's 307 00:17:49,860 --> 00:17:53,320 the most important 308 00:17:55,080 --> 00:17:58,530 energy-carrying molecule in the cell. 309 00:17:58,530 --> 00:18:01,860 And without sufficient amounts of ATP, most cells die. 310 00:18:01,860 --> 00:18:04,620 So it's not the only energy-carrying molecule, 311 00:18:04,620 --> 00:18:06,453 but it's the most important one. 312 00:18:11,850 --> 00:18:16,230 So ATP consists of three components, 313 00:18:16,230 --> 00:18:18,660 adenine, which is a nucleobase, 314 00:18:18,660 --> 00:18:20,460 ribose, which is a sugar, 315 00:18:20,460 --> 00:18:23,160 and three phosphate molecules, 316 00:18:23,160 --> 00:18:25,803 so triphosphate 3. 317 00:18:27,120 --> 00:18:32,120 And the two outermost phosphates represent high-energy bonds 318 00:18:33,270 --> 00:18:37,770 that are storing potential energy within this ATP molecule. 319 00:18:37,770 --> 00:18:40,800 So when those bonds are broken, 320 00:18:40,800 --> 00:18:43,020 that's when the energy is released. 321 00:18:43,020 --> 00:18:46,920 So ATP is essential for repeated muscle contraction 322 00:18:46,920 --> 00:18:49,770 and must be rapidly regenerated when work is performed, 323 00:18:49,770 --> 00:18:53,190 because the body only stores small amounts of ATP. 324 00:18:53,190 --> 00:18:57,753 So we need to constantly be reproducing that. 325 00:18:59,940 --> 00:19:01,680 Formation of ATP occurs 326 00:19:01,680 --> 00:19:06,680 by combining adenine diphosphate or two phosphates, ADP. 327 00:19:07,380 --> 00:19:12,380 So it's combining ADP and an inorganic, no carbon phosphate, 328 00:19:13,530 --> 00:19:14,610 so another P. 329 00:19:14,610 --> 00:19:17,700 So you add a P to the ADP, 330 00:19:17,700 --> 00:19:20,883 and you get a TP, triphosphate. 331 00:19:21,720 --> 00:19:26,720 So some of this energy is stored in the chemical bond 332 00:19:27,060 --> 00:19:30,660 that's joining ADP and a P. 333 00:19:30,660 --> 00:19:32,880 This bond is called a high-energy bond. 334 00:19:32,880 --> 00:19:35,760 That's the one that I was talking about in the prior slide. 335 00:19:35,760 --> 00:19:40,760 And when ATPase, if you recall, ase is an enzyme, 336 00:19:40,770 --> 00:19:43,080 breaks that bond, 337 00:19:43,080 --> 00:19:45,090 that two phosphate bond, 338 00:19:45,090 --> 00:19:48,540 energy is released and the energy can be used to do work. 339 00:19:48,540 --> 00:19:53,283 So we need that ATPase, 340 00:19:54,263 --> 00:19:58,860 the enzyme to break the chemical bond 341 00:19:58,860 --> 00:20:02,102 between the adenosine diphosphate 342 00:20:02,102 --> 00:20:03,603 and the inorganic phosphate.