2.3 carbohydrates and lipids
Transcript of 2.3 carbohydrates and lipids
2.3 Carbohydrates and Lipids
GuidanceThe structure of starch should include amylose and amylopectin.Named examples of fatty acids are not required.Sucrose, lactose, and maltose should be included as examples of disaccharides produced by combining monosaccharides.
Understandings• Monosaccharide monomers are linked
together by condensation reactions to form disaccharide and polysaccharide polymers
• Fatty acids can be saturated, monounsaturated, or polyunsaturated.
• Unsaturated fatty acids can be cis or trans isomers.
• Triglycerides are formed by condensation reactions from three fatty acids and one glycerol.
Applications/Skills• A: Structure and function of cellulose and
starch in plants and glycogen in humans.• A: Scientific evidence for health risks of trans
fats and saturated fatty acids.• A: Lipids are more suitable for long-term
energy storage in humans than carbohydrates.• A: Evaluation of evidence and the methods
used to obtain the evidence for health claims made about lipids.
• S: Use of molecular visualization software to compare cellulose, starch, and glycogen.
• S: Determination of body mass index by calculation or use of a nomogram.
Carbohydrates
Monosaccharide: one sugar unit
Examples: glucose (C6H12O6)deoxyriboseriboseFructoseGalactose
https://cdavies.wordpress.com/2009/01/27/simple-sugars-fructose-glucose-and-sucrose/
Carbohydrates
Disaccharide: two sugar unitExamples: • Sucrose (glucose+fructose)• Lactose (glucose+galactose)• Maltose (glucose+glucose)
http://www.cheesescience.com/wp-content/uploads/2011/09/glulac.jpg
Polysaccharides
Polysaccharide
Function
Cellulose Provide rigidity and support in plants
Starch Product of photosynthesis; stored as granules in roots/root structures
Glycogen Stored excess glucose in liver and muscle tissue
http://bio.classes.ucsc.edu/bio20L/glossary/struc/starch.gif
All composed of the same monomer (glucose)
1,4 linkages
GlycogenAn insoluble storage molecule in the liver. When blood glucose is high, the pancreas releases insulin, telling the liver to capture blood glucose and combine molecules of glucose to make the polysaccharide glycogen, through condensation reactions.
This stores energy for later.
When blood glucose drops, the hormone glucagon causes the glycogen to be broken down (hydrolysis reactions) to glucose and then released back into the blood.
Liver from: http://en.wikipedia.org/wiki/File:Leber_Schaf.jpg
Fatty Acids
There are two kinds of fatty acids you may see these on food labels:1. Saturated fatty acids: no double bonds (bad)2. Unsaturated fatty acids: double bonds (good)
http://foodscienceacademy.org/wp-content/uploads/2013/06/fat_f2.jpg
Unsaturated Fatty Acids• Monounsaturated
• Only one double bond present
• Animal fats• Usually solid at room temp• Bent shape
• Polyunsaturated• Two or more double bonds
present• Usually from plants• Usually liquid at room temp• Curved shape
Adapted from http://e004777c130eade00234-5ddb36df15af65ab8482e83373c53fe5.r41.cf1.rackcdn.com/images/30.jpg
Cis vs trans fatty acidsTrans Fatty Acids Cis Fatty Acids- Processed foods
- Hydrogenated
- Straightened out
- Ex: hydrogenated oils
- More curved
- Generally considered healthier
- Ex: omega-3
http://www.nutrientsreview.com/wp-content/uploads/2014/12/Trans-cis-fatty-acid.jpg
Triglycerides
Formed by condensation reaction between three fatty acids and a glycerol
http://erichamber.ca/departments/science/dfung/pages/biology/biologic/fatty_acid_glycerol.gif
Lipids for Energy Storage
• Lipids can be hydrolyzed into 2 carbon segments for cell respiration• Twice the energy per gram compared to glucose• Not soluble in water, so won’t disrupt osmotic balance in
cells• Carbohydrates are soluble in water, so water would enter the cell,
causing it to swell.
BMI
• Formula 1 (metric):weight in kg/(height in m)(height in m)
• Formula 2 (imperial): [weight in lb/(height in in)(height in in)] X 703
http://www.vertex42.com/ExcelTemplates/Images/body-mass-index-chart.gif
Homework
Vocab• Triose• Pentose• Hexose• Saturated fatty acid• Monounsaturated fatty acid• Polyunsaturated fatty acid• Omega-3 fatty acid• Triglyceride• Glycogen • BMI
Other• Challenge yourself 3-6• Exercises 6-8• Nature of science (choose
one)