Essential Characteristics of Life — Transcript

Full transcript

1. 0:02[Music]
2. 0:05hi it's Mr Anderson and welcome to
3. 0:07biology Essentials video number five
4. 0:09this is on the essential characteristics
5. 0:11and how they're conserved uh today I'm
6. 0:13going to be talking
7. 0:14about life uh this right here is a tree
8. 0:17of life a circular tree of life and you
9. 0:20can see that this tree of life is going
10. 0:21to Branch over to here these would be
11. 0:23like the
12. 0:24ARA um these would be the
13. 0:27ukaria uh we would be humans would be
14. 0:30right here if I can read that right uh
15. 0:32these are going to be the bacteria that
16. 0:33go over here and so we have this tree of
17. 0:36life that tells us a few things number
18. 0:38one we're more related uh to ARA than we
19. 0:41are to bacteria um but it also shows
20. 0:45that there are certain characteristics
21. 0:46that are shared by all of life in other
22. 0:48words all of life has DNA and so that
23. 0:52must have originated very early in this
24. 0:54tree of life and so today what I'm going
25. 0:56to talk about are essential are
26. 0:58essentially um characteristics essential
27. 1:01characteristics in other words things
28. 1:03that are required for life and how
29. 1:04they're conserved or how they stick
30. 1:06around um through time uh if we kind of
31. 1:09plan this out uh I this is what I want
32. 1:12to talk about I want to talk about three
33. 1:14things and how they're conserved uh the
34. 1:15first one would be the genetic code and
35. 1:17that's DNA uh next thing is the central
36. 1:20dogma and that's uh how DNA eventually
37. 1:23makes um RNA and how RNA make proteins
38. 1:26and then make you and then some
39. 1:27metabolic pathways uh metabolism is the
40. 1:30sum of all chemical reactions inside
41. 1:32life and there are some really
42. 1:33fundamental things that you may not know
43. 1:35that are found within these three groups
44. 1:37so these would be the three domains we
45. 1:39call that bacteria ARA and ukaria and so
46. 1:42all life fits into one of these three
47. 1:45categories and so these three things are
48. 1:48conserved or found in all of life we'll
49. 1:51also find that we move up that tree a
50. 1:53little bit when we get to the ukari
51. 1:55there are going to be characteristics
52. 1:56that are shared within them as well uh
53. 1:59and so as we go farther farther and
54. 2:00farther and farther up that uh tree of
55. 2:02life we find more and more
56. 2:04characteristics and and we get finer and
57. 2:05finer detail as we move our our way up
58. 2:08so uh let me quit talking about what I'm
59. 2:09going to talk about and actually do it
60. 2:12let's start with the first one and that
61. 2:13is the genetic code and that is
62. 2:17DNA so you should be familiar with this
63. 2:20that double helix structure um most
64. 2:22people know what DNA is but they don't
65. 2:24necessarily know what it does um an
66. 2:27example would be this um a jellyfish
67. 2:30right here scientists were able to take
68. 2:32a uh Gene out of a jellyfish that makes
69. 2:35a glowing protein that allows that
70. 2:36jellyfish to do well deep in the ocean
71. 2:39uh they were able to take that DNA and
72. 2:41put it into a bacteria this is a really
73. 2:44cool picture it's a petri dish where a
74. 2:45scientists put different genes inside
75. 2:48the bacteria to make them glow in this
76. 2:49case it's making it grow glow this kind
77. 2:51of a a green color we've also been able
78. 2:55to put it inside fish and make fish that
79. 2:58glow green and so the genetic code is
80. 3:01found in all of life in other words it's
81. 3:03Universal we've never found anything
82. 3:06that doesn't use uh DNA as its genetic
83. 3:08material or RNA uh if we talk about
84. 3:11viruses and so this is found in all of
85. 3:13life and it's also interchangeable which
86. 3:15is cool we can take the DNA back out of
87. 3:17here put it in here put it back we can
88. 3:19put it anywhere and DNA is going to be
89. 3:21Universal and so that suggest that all
90. 3:24life uh comes from this one common
91. 3:26ancestor next thing is the idea of uh
92. 3:29the central Dogma central dogma you may
93. 3:31not be familiar with that but you should
94. 3:33know what it is um Watson and Crick were
95. 3:35the people who got credit for um diso
96. 3:39discovering the structure of DNA but
97. 3:42this guy right here Francis Crick spent
98. 3:44the next then uh 10 years figuring out
99. 3:46well the Machinery behind the DNA and so
100. 3:48what it actually does and so he
101. 3:51summarized it right here and so
102. 3:52essentially what happens is DNA can copy
103. 3:54itself we call that DNA replication it
104. 3:57then through transcription makes RNA RNA
105. 4:00makes proteins and a protein eventually
106. 4:03uh makes you and so every part of you is
107. 4:07made up of proteins and the result of
108. 4:09protein action and so um all life goes
109. 4:13through the same mechanism in other
110. 4:15words in bacteria they have the genetic
111. 4:17material as DNA they make RNA out of it
112. 4:20and then they make Pro proteins now the
113. 4:22way that they do that the ribosomes that
114. 4:24they use are a little bit different but
115. 4:25the mechanism is is going to be exactly
116. 4:27the same and so we've never found life
117. 4:30that doesn't utilize this central dogma
118. 4:32remember you pass your DNA on and then
119. 4:34the cycle can begin uh again and the
120. 4:37last one is metabolism metabolism
121. 4:39remember is how we kind of make use of
122. 4:41the energy that that's given to us and
123. 4:44so it summarizes here in other words we
124. 4:47as humans and fungi and and a lot of
125. 4:49bacteria can take in organic material
126. 4:51and oxygen uh we then make carbon
127. 4:53dioxide and water this is called
128. 4:55cellular respiration and then there are
129. 4:57certain producers that can actually make
130. 5:00that again whereas plants are making
131. 5:02sugar so they can actually break it down
132. 5:05but regardless of all of that there are
133. 5:07a few things that are found in all
134. 5:09living organisms and so if you know what
135. 5:12a DNA is and you know that all life has
136. 5:15it you should also realize that this is
137. 5:17the coinage the energy coinage that all
138. 5:20life uses as well and so if I ever heard
139. 5:22that we discovered life on some other
140. 5:24planet I want to know what's the
141. 5:25hereditary material and then what is it
142. 5:28how is it making its energy what's it
143. 5:29using for metabolism and so the
144. 5:31fundamental ways that we utilize energy
145. 5:33or get energy and make ATP is through
146. 5:36gsis KB cycle and oxidative
147. 5:39phosphorilation so all life uses one of
148. 5:42those and either anerobic or aerobic
149. 5:45respiration and so bacteria fungi
150. 5:48whatever we're making ATP and we're
151. 5:51using the same fundamental metabolic
152. 5:53pathways and what does that suggest
153. 5:55going way back to that tree of life that
154. 5:57it originated very early in the life uh
155. 5:59on our planet and it's been passed down
156. 6:02uh through time but we'll get more into
157. 6:03detail on on respiration photosynthesis
158. 6:06a little bit later now if we go to the
159. 6:09next group um so remember we have if I
160. 6:12were to sketch it out we have the
161. 6:14breakoff of bacteria domain we also have
162. 6:18the branching off of
163. 6:20ARA these ancient life and then finally
164. 6:25we have ukaria and that's what you are
165. 6:28and actually everything on here from
166. 6:31animals all the way over to fungi down
167. 6:34in here to unicellular organism and
168. 6:36plants and all these things are ukari
169. 6:40now they are a different kind of a cell
170. 6:42and so what do you know about a ukari it
171. 6:44actually if I remember right cararo
172. 6:46comes from egg and so the best way to
173. 6:48think about um a eukaryotic cell is that
174. 6:51it has a nucleus so it has a nuclei on
175. 6:54the inside where it stores its DNA but
176. 6:57how did we go from these simple cells
177. 7:00to cells that are eukariotic and have a
178. 7:03division of labor inside the cell itself
179. 7:05well there's actually two ways that we
180. 7:07did that and two characteristics that I
181. 7:08chose to talk about related to UK carots
182. 7:11tell us how we got there so let me clear
183. 7:12that off and get to the endomembrane
184. 7:14system and so the first way that cells
185. 7:17move from very simple cells to more
186. 7:19complex cells well if you think about it
187. 7:21let's say I have one cell this is really
188. 7:23simple but how can I make that more
189. 7:25complex well a really simple way to make
190. 7:27that complex is to have it f in on
191. 7:29itself and if I have it fold in on
192. 7:32itself now I have an increase in surface
193. 7:34area and so I can I can do other jobs
194. 7:37and so we have a number of things so you
195. 7:39know the gogia apparatus endoplasmic
196. 7:41reticulum lomes vesicles all these
197. 7:44things are made we think from the
198. 7:46infolding of this What's called the
199. 7:48endomembrane system or a membrane on the
200. 7:50inside now what's interesting is that we
201. 7:52can actually look at proteins on the
202. 7:54outside of the cell and proteins on the
203. 7:57inside of the cell oops let me go back
204. 7:59for per second and proteins on the
205. 8:01inside of the cell and we find that
206. 8:04they'll actually be reversed in other
207. 8:06words ones that on the outside of the
208. 8:08cell will now be let me get this right
209. 8:10on the outside of this and vice versa
210. 8:13here so we also have some strong
211. 8:15molecular evidence as well to show that
212. 8:17this infolding has occurred and so
213. 8:19that's a common characteristic this
214. 8:20endomembrane system of all eukariotic
215. 8:23cells and then another example would be
216. 8:26uh organel themselves the two specific
217. 8:28ones that I'd like to talk about are the
218. 8:29mitochondria which we use to get energy
219. 8:32out of our uh food to do oxidative
220. 8:34phosphorilation and get as much ATP as
221. 8:36we can and then the chloroplast which is
222. 8:38used in plants and a lot of
223. 8:40photosynthetic UK carots to actually
224. 8:42take energy from the Sun and then use
225. 8:44that fix carbon now what's interesting
226. 8:46about these two is that they are not
227. 8:48formed we don't think by an infolding of
228. 8:51the membrane they're not part of that
229. 8:52endomembrane system so that's not them
230. 8:55these actually were formed by
231. 8:56endosymbiosis and so what we think is
232. 8:59that
233. 8:59the um mitochondria was a bacteria once
234. 9:02on its own it was living in CL close
235. 9:05proximity to these early eukaryotic
236. 9:06cells and then eventually started Living
237. 9:09inside and so it's actually a cell
238. 9:12within a cell now what kind of evidence
239. 9:14do we have because that seems crazy that
240. 9:16this is actually occurring well if you
241. 9:17look inside here we actually have DNA
242. 9:19inside of
243. 9:20mitochondria and and so they're actually
244. 9:22reproducing by binary fision on their
245. 9:24own and they have a lot of properties
246. 9:25that are very similar to um bacteria and
247. 9:28we think Chlor plast got into plant
248. 9:30cells in the same exact way and so
249. 9:32they're kind of hijacking or living
250. 9:33inside of us at this time so it's a cool
251. 9:35way that we can get complex UK carots uh
252. 9:38and so those are some common
253. 9:39characteristics of um of ukari and I
254. 9:43guess the whole General point of this
255. 9:44video podcast is that if you come up
256. 9:47with a solution that solution is going
257. 9:49to be passed up the tree of life there's
258. 9:51no way to we could step back and say hey
259. 9:53let's find a new genetic information
260. 9:55let's use something else that decision
261. 9:57was made billions of years ago and so I
262. 9:59hope that's helpful