Monosaccharides - Glucose, Fructose, Galactose, & Ribose - Carbohydrates — Transcript

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1. 0:01in this video we're going to talk about
2. 0:03carbohydrates
3. 0:05we're going to briefly review
4. 0:07monosaccharides
5. 0:08disaccharides and polysaccharides
6. 0:12let's start with monosaccharides
7. 0:14the word mono means one
8. 0:17so we're going to go over
9. 0:19the simple sugar units
10. 0:22the first one is glucose
11. 0:24i'm going to draw that real quick
12. 0:27glucose
13. 0:28is
14. 0:29a monosaccharide with six carbons
15. 0:34this is
16. 0:35the cyclic form of glucose
17. 0:38it does have a linear form as well
18. 0:45and so this is how it looks like
19. 0:51this is the alpha form of glucose
20. 0:54with the hydroxyl group down on carbon
21. 0:561.
22. 0:57this is carbon one two
23. 0:59three
24. 1:00four
25. 1:01five six
26. 1:04the chemical formula for glucose is
27. 1:06c6h12o6
28. 1:09and it turns out that carbohydrates have
29. 1:12the empirical formula
30. 1:13c1h2o1
31. 1:17thus you can see the word carbon and
32. 1:19hydrate
33. 1:21thus carbohydrates
34. 1:25fructose
35. 1:28forms a five-membered ring in its cyclic
36. 1:31form
37. 1:31but fructose have the same chemical
38. 1:34formula as glucose
39. 1:37and the structure
40. 1:38looks like this
41. 1:53fructose is a keto hexose
42. 1:57in its linear structure it forms a
43. 1:59ketone
44. 2:01a ketone rather functional group
45. 2:03glucose is an aldo hexose
46. 2:06in its straight chain function i mean
47. 2:08straight chain structure rather it forms
48. 2:10an aldehyde functional group
49. 2:13glucose and fructose
50. 2:16are known as isomers of each other
51. 2:20they have the same chemical formula
52. 2:22c6h12o6
53. 2:24but as you can see
54. 2:26they form different structures
55. 2:28another one that you need to be familiar
56. 2:30with is
57. 2:31a monosaccharide called
58. 2:33galactose
59. 2:37glucose and galactose
60. 2:40are very similar
61. 2:42they both form six membered rings
62. 2:45and are both aldo hexoses
63. 2:54notice the key difference between the
64. 2:55two
65. 2:56there's one small difference between
66. 2:58glucose and galactose
67. 3:02do you see what it is
68. 3:06glucose and galactose they differ
69. 3:09at carbon 4.
70. 3:11at carbon 4 the hydroxyl group is
71. 3:13pointed up in galactose
72. 3:15but in glucose it's pointing down
73. 3:18everything else is the same
74. 3:21glucose and galactose are known as
75. 3:23stereoisomers
76. 3:26they have the same chemical formula
77. 3:28their atoms are connected the same way
78. 3:31they have the same functional groups but
79. 3:33the only difference is that the way
80. 3:36their hydroxyl groups are oriented in
81. 3:38space
82. 3:40stereo isomers have the same
83. 3:41connectivity but
84. 3:43different spatial arrangements of the
85. 3:45atoms
86. 3:47so glucose and galactose are
87. 3:49stereoisomers
88. 3:51now galactose is specifically called a
89. 3:54c4 epimer of glucose
90. 3:57because it is that carbon 4 that they
91. 3:59differ
92. 4:02and they only differ at one particular
93. 4:04carbon not two or more carbons
94. 4:06which makes it an epimer
95. 4:09now there are some other monosaccharides
96. 4:11that
97. 4:12you may want to be familiar with
98. 4:18the next one that i'm going to draw
99. 4:20is a sugar called
100. 4:22ribose
101. 4:25ribose
102. 4:26is a five carbon sugar
103. 4:28and it also forms a five-membered ring
104. 4:38so that's the structure of ribose
105. 4:41now ribose
106. 4:44is the sugar that is found
107. 4:46in nucleic acids such as rna
108. 4:49rna stands for ribonucleic acid
109. 4:54now there is another five carbon sugar
110. 4:57that you need to be familiar with
111. 5:00and the one i'm going to draw
112. 5:04is called deoxy ribose
113. 5:08look at the difference between these two
114. 5:09structures what do you notice
115. 5:13notice that the hydroxyl group has been
116. 5:15replaced with a hydrogen
117. 5:17so that's why it's called
118. 5:19deoxy ribose
119. 5:21another five carbon sugar
120. 5:24deoxyribose is found in a different
121. 5:26nucleic acid
122. 5:28called dna which stands for
123. 5:30deoxyribonucleic acid
124. 5:32so those are some other two sugars that
125. 5:34you want to be familiar with
126. 5:36and the simplest sugar
127. 5:38is known as glyceraldehyde
128. 5:41this is
129. 5:42a three carbon
130. 5:44sugar
131. 5:50so that's it for the monosaccharides so
132. 5:53monosaccharides are basically one sugar
133. 5:56units