Lecture 17: Intro to Carbohydrates
BMB 200
Rebecca Morningstar
Objectives:
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Students will be able to classify sugars as monosaccharides, disaccharides,
oligosaccharides, or polysaccharides.
Students will be able to distinguish between aldoses and ketoses.
Students will be able to classify simple sugars as trioses, tetroses, pentoses, hexoses, or
heptoses based on the number of carbons.
Students will be able to assess chirality of simple sugars and classify them as either
D- or L-configuration.
Given a Fischer or Haworth projection of a sugar, students will be able to convert it to
the other format.
Students will be able to differentiate between axial and equatorial bonds and the
stability of sugars with differing structures.
Students will be able to identify common carbohydrates based on given information:
Glucose, Fructose, Lactose, Sucrose, Maltose, Starch, Glycogen, Cellulose, Chitin.
Science Summary:
Carbohydrates are one of the four major classes of biomolecules. They follow a general
formula of CH2O (Carbo-hydrate) and are divided into size classes. Monosaccharides are
the building blocks for all larger carbohydrates and have 3-7 carbons. Disaccharides are
2 monosaccharides joined by a glycosidic bond. Oligosaccharides are a few
monosaccharides joined, and polysaccharides, such as starch and chitin, are many
monosaccharides joined in a chain. Chirality is also important in sugars, as it affects
chemical properties and activity of the sugars. Sugar can take either D- or Lconfigurations, but are typically D- in nature. Sugars can also exist in straight chain or
ring formations, but common sugars such as glucose and fructose, tend to “prefer” the
ring configuration.
Materials:
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Powerpoint/Projector
Organic Model Kit
iClickers
Vocabulary/Key Terms:
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Simple Sugar
Complex Sugar
Monosaccharide
Disaccharide
Oligosaccharide
Polysaccharide
Aldose
Ketose
Triose
Tetrose
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Pentose
Hexose
Heptose
Fischer Projection
Haworth Projection
Chirality
Hemiacetal
Hemiketal
Axial bond
Equatorial bond
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Glucose
Fructose
Maltose
Lactose
Sucrose
Starch
Glycogen
Cellulose
Chitin
Constructivist Activities:
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Dynamic Notebook Activity:
o Tasks outlined on ppt slides. Students complete on their own and then discuss
with neighbors. “If you disagree, convince each other!” Can make corrections
based on discussion with neighbors and turn in on the way out for 5 points.
o Details:
 Part 1: On the TOP HALF of a blank sheet of paper, draw a sugar with the
following characteristics: Pentose, Aldose. We will be adding to this, so
leave room for additions.
 Part 2: Look at the sugar you drew. Is it in D- or L- configuration? Label this on
your drawing and write a one-sentence explanation for how you determined
your answer. Hint: Drawing arrows to specific parts of your diagram may
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help with the explanation.
Part 3: On the bottom half of your paper, draw your sugar in a Haworth
projection.
Part 4: Discuss your drawings and classifications with your neighbor. Do you
both agree with the classifications you’ve made? If not, try to convince each
other of the correct answers!
Possible second activity:
 Given the following monosaccharides, work with your neighbor to draw the
mechanism for glycosidic bond formation and the resulting disaccharide.
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Clicker Questions with time for class discussion
Instruction:
Lesson:
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Carbohydrates- name derivation
Mono/Di/Oligo/Poly-saccharides- naming
Monosaccharides
o Intro
o Aldoses/Ketoses
o Triose-Heptose
o Fischer projections
o CLICKER QUESTIONS
o NOTEBOOK ACTIVITY, Part 1
o Chirality
o NOTEBOOK ACTIVITY, Part 2
o Cyclic structures
o Haworth Projections
o NOTEBOOK ACTIVITY, Part 3
o Hexose conformations
o Bond types/Sterics
o Glucose
o Fructose
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Disaccharides
o Glycosidic Bonds
o NOTEBOOK ACTIVITY?
o Maltose
o Lactose
o Sucrose
o Reducing sugars
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Oligosaccharides
o Stachyose
o Properties
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Polysaccharides
o Intro- Types, Branching, etc
o Starch
o Glycogen
o Dextrans
o Cellulose
o Chitin
o Agar
Homework:
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Answer the six questions in the “Problems” section of the online text for Ch 7. (5 pt)
Read assigned papers (See Syllabus)
Assessment:
Formative:
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Clicker questions
Notebook Activities
Summative:
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Homework
Exam Questions
Diet analysis- Why do dieticians recommend this diet for diabetic patients? (Rubric and
assignment information provided with Lecture #28 Lesson Plans
Sample Assessment Questions:
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Is this sugar:
o A monosaccharide?
o A disaccharide?
o An oligosaccharide?
o A polysaccharide?
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Is this sugar:
o An Aldose
o A Ketose
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Is this sugar:
o A triose
o A tetrose
o A pentose
o A hexose
o A heptose
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Label the Chirality of this sugar (D- or L-)
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Is this an α or β sugar? Label the appropriate carbon on the diagram.
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Draw glucose in both a Fischer Projection and a Haworth Projection.
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IN YOUR OWN WORDS, describe why many polysaccharides are branched. What is the
mechanism by which they become branched?
Notes/Reflection: