2.3: Carbohydrates and Lipids

Terms in this set (30)

Define monosaccharide.



Understanding: Monosaccharide monomers are linked together by condensation reactions to form disaccharides and polysaccharide polymers.
The simplest form of carbohydrate; "one sugar."
Define disaccharide.



Understanding: Monosaccharide monomers are linked together by condensation reactions to form disaccharides and polysaccharide polymers.
The sugar formed when two monosaccharides are joined; "two sugar."
Define polysaccharide.



Understanding: Monosaccharide monomers are linked together by condensation reactions to form disaccharides and polysaccharide polymers.
Long chains of bonded monosaccharides; "many sugars."
List three examples of monosaccharides.



Understanding: Monosaccharide monomers are linked together by condensation reactions to form disaccharides and polysaccharide polymers.
Glucose (C6H12O6)
Ribose (C5H10O5)
Deoxyribose (C5H10O4)
Fructose (C6H12O6)
Galactose (C6H12O6)
List three examples of disaccharides.



Understanding: Monosaccharide monomers are linked together by condensation reactions to form disaccharides and polysaccharide polymers.
Maltose (glucose + glucose)
Sucrose (glucose + fructose)
Lactose (glucose + galactose)
List three examples of polysaccharides.



Understanding: Monosaccharide monomers are linked together by condensation reactions to form disaccharides and polysaccharide polymers.
Starch: polymer of alpha-glucose (amylose and amylopectin)

Cellulose: polymer of beta-glucose

Glycogen: polymer of alpha-glucose
Draw the formation of maltose from two glucose monomers.



Understanding: Monosaccharide monomers are linked together by condensation reactions to form disaccharides and polysaccharide polymers.
Carbon #1 of one glucose binds to carbon #4 of the other glucose
Explain a condensation reaction connecting two monosaccharides in the formation of a disaccharide.



Understanding: Monosaccharide monomers are linked together by condensation reactions to form disaccharides and polysaccharide polymers.
Condensation is a chemical reaction in which two molecules are joined to make a larger molecule with the loss of water.

An -H from the hydroxyl on carbon #1 of one monosaccharide combines with an -OH from the hydroxyl on carbon #4 of the other monosaccharide. The -H and _OH combine to form water. A bond is formed with a C-O-C bridge between the two monosaccharides.
Describe the differences between saturated and unsaturated (mono- or poly-) fatty acids.



Understanding: Fatty acids can be saturated, monounsaturated and polyunsaturated.
Saturated fatty acids have only single carbon-to-carbon bonds (therefore the carbons are saturated with hydrogen atoms)

Unsaturated fatty acids have one ("mono") or more ("poly") carbon-to-carbon double bonds.
Define "isomer."



Understanding: Unsaturated fatty acids can be cis or trans isomers.
Isomers are molecules that have the same molecular formula but a different arrangement of atoms.
Describe the differences between cis- and trans- fatty acids.



Understanding: Unsaturated fatty acids can be cis or trans isomers.
Cis and trans fatty acids have the same molecular formula but different arrangements of H- atoms relative to the C=C.

Trans: H atoms are on the opposite sides of the C=C

Cis: H atoms are on the same side of the C=C.
Outline the difference between fats and oils.



Understanding: Triglycerides are formed by condensation from three fatty acids and one glycerol.
Fats
Solid at room temperature
Typically from animal sources
Contain more saturated fatty acids
examples: butter and lard

Oils
Liquid at room temperature
Typically from plant sources
Contain more unsaturated fatty acids
examples: olive oil
Explain a condensation reaction connecting fatty acids and glycerol to form a triglyceride.



Understanding: Triglycerides are formed by condensation from three fatty acids and one glycerol.
Three molecules of fatty acid combine with one molecule of glycerol with the removal of three molecules of water. The resulting compound is called a triglyceride.
State two functions of triglycerides.



Understanding: Triglycerides are formed by condensation from three fatty acids and one glycerol.
-source of energy
-storage of chemical energy
-thermal insulation
-waterproofing
-protection
State the structural difference between alpha and beta glucose.



Application: Structure and function of cellulose and starch in plants and glycogen in humans.
The only (but significant) difference between alpha and beta glucose is the orientation of the hydroxyl group (-OH) relative to carbon #1 of the molecule.

Alpha glucose: the -OH goes "down"
Beta glucose: the -OH goes "up"
Describe the structure and function of cellulose.



Application: Structure and function of cellulose and starch in plants and glycogen in humans.
Cellulose is a straight chain (unbranched) polymer of beta glucose molecules that forms the plant cell wall. Hydrogen bonds form between cellulose chains.
Describe the structure and function of amylose.



Application: Structure and function of cellulose and starch in plants and glycogen in humans.
Amylose consists of a linear chain of roughly 500 to 20,000 alpha-glucose monomers linked together. Amylose is a energy storage molecule found in plants.
Describe the structure and function of amylopectin.



Application: Structure and function of cellulose and starch in plants and glycogen in humans.
Amylopectin consists of a branching chain of roughly 1-2 million alpha-glucose monomers linked together. Amylopectin is a energy storage molecule found in plants.
Describe the structure and function of glycogen.



Application: Structure and function of cellulose and starch in plants and glycogen in humans.
Glycogen consists of a highly branched chain of alpha-glucose monomers linked together. Glycogen is a energy storage molecule found in animals.
Outline the use of trans-fats in food.



Application: Scientific evidence for health risks of trans fat and saturated fatty acids.
Trans fat, also called trans-unsaturated fatty acids or trans fatty acids, are a type of unsaturated fat that occur in small amounts in nature but became widely produced industrially from vegetable fats starting in the 1950s for use in margarine, snack food, and packaged baked goods and for frying fast food. Use of trans fats in food is now banned in the USA.
Outline the health risks of trans-fats and saturated fats in food.



Application: Scientific evidence for health risks of trans fat and saturated fatty acids.
There is a direct, strong correlation between intake of trans-fats and saturated fats in food and:
1. all causes of mortality
2. cardiovascular disease
3. coronary heart disease
4. stroke
5. type II diabetes
Compare the energy storage of lipids to that of carbohydrates.



Application: Lipids are more suitable for long term energy storage in humans than carbohydrates.
Lipids
Slow release of energy
Able to store chemical energy long term
≈ 2X the energy per gram compared to carbs
Insoluble, so easier to store

Carbohydrates
Fast release of energy
Quickly digested and used
≈ 1/2 the energy per gram compares to lipids
Soluble, so easy to transport by blood
Describe how health claims can be evaluated.



Application: Evaluation of evidence and the methods used to obtain the evidence for health claims made about lipids.
Health claims can be evaluated using a systematic analysis of the claim:

Does scientific research support the claim?
-How strong is a correlection?
-Is a result determined to be statistically significant?
-How much variation is there between people?

What are the limitations of the research?
-Was there a large sample size?
-Were relevant variables controlled?
-How accurate are the measurement techniques?

Are there financial reasons for making a claim?
-Is the claim maker trying to sell a product?
Identify carbon, hydrogen and oxygen atoms by color in molecular visualization software.



Skill: Use of molecular visualization software to compare cellulose, starch and glycogen.
Carbon = black
Hydrogen = white
Oxygen = red
Describe how molecular visualization software is used to compare molecules.



Skill: Use of molecular visualization software to compare cellulose, starch and glycogen.
Molecular visualization software (like Jmol) allows molecule models to be viewed, rotated, zoomed and manipulated.
Outline the use of the body mass index (BMI).



Skill: Determination of body mass index by calculation or use of a nomogram.
The a body mass index (BMI) is a weight-to-height ratio, calculated by dividing one's weight in kilograms by the square of one's height in meters and used as an indicator of obesity and underweight.
Given weight and height, calculate the BMI.



Skill: Determination of body mass index by calculation or use of a nomogram.
BMI = weight / (height X height)

if weight = 77 kg and height = 1.9 m
then BMI = 77 / (1.9x1.9)
BMI = 77 / 3.61 = 21. 3
Given weight and height, use a nomogram to determine the BMI.



Skill: Determination of body mass index by calculation or use of a nomogram.
Connect the weight and height with a straight line. BMI is the point at which the line crosses the center scale.
Outline effects of a BMI that is too high or too low.



Skill: Determination of body mass index by calculation or use of a nomogram.
A high BMI can be an indicator of obesity, which correlates to health problems, including:
- Type II diabetes
- Gallstones
- Hypertension
- Heart disease

A low BMI can be an indicator of malnourishment.

Note, use of BMI has limitations because it doesn't distinguish mass from fat, muscle or bone. Might misclassify healthy people as obese and visa versa.
Describe how the effect of lipids on health can be assessed scientifically.



Nature of Science: Evaluating claims- health claims made about lipids in diets need to be assessed.
The effects of lipids on health can be assessed using scientific investigations, including:

-determining correlations between dietary lipids and health effects using large databases of population statistics

-performing controlled experiments with human volunteers or animal models.
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