Week 3 Application Questions Flashcards
The spike protein of the SARS- CoV-2 virus is connected to carbohydrates, and therefore often referred to as a glycoprotein.
The building block of these carbohydrates is mannose (C6H12O6, see Fig. 1).
How would you describe the differences between mannose and glucose?
Why are there two forms of Mannose?
What is the technical term for this?
- Structural isomers: same number of C, O, H, functional groups
- Differ in the position of the hydroxyl group at the C2 atom
*
- Are mirror images. Differ in the three dimensional space, e.g. hands and gloves
- Becomes important with regard to substrates for enzymes
*
- Enantiomers
What role do mono- and di-saccharides play in our diet?
– Energy for our cells!
– Absorbed into bloodstream
quickly → causes blood
sugar to spike
– Simple sugars = mono-+ disaccharides
– Complex sugars = long and/or branched carbohydrates
We have enzymes in our digestive system that help us to break down starches.
What is the chemical function of these enzymes?
– Amylase enzymes found in saliva and gut
– Break α-1,4-glycosidic bonds to produce glucose
* Hydrolysis reaction (uses water)
* Releases energy
– Allows us to release sugar from starches in food
Blood sugar is the amount of simple sugar in the blood that is available for cells.
Eating a chocolate bar will cause a rapid increase in blood sugar, while eating a potato will cause a much slower increase in blood sugar. Explain why.
- Sugar absorbed into bloodstream immediately
- Starches must be digested by amylase to release sugars
– Enter bloodstream more slowly
– Produce slower, more even
increase in blood sugar
Cellulose is a major type of fiber in our diet.
Look at the chemical structures of starch and cellulose (in the notes), and predict why we are unable to digest cellulose, even though we are able to digest starch.
Why can cows survive by eating grass, while we can’t?
– We don’t have enzymes to break β-1,4-glycosidic bonds, so no energy (sugar) can be obtained
– Fiber is important!
Promotes digestive health
– Bacteria in cows’ stomachs produce cellulase enzymes to break β-1,4-glycosidic bonds and release glucose
Gold fish. What types of lipids are present on the nutrition label?
Fats = 3.5 g
Saturated fats = 0.5 g
Trans-unsaturated fats = 0 g*
Cholesterol = 5 mg
What are the other 3 g?
Does the food you chose contain trans fats?
What is a trans fat, and where do they come from?
- What are the other 3 g?
- Cis-unsaturated fats
Phospholipids - Trans fats contain double bonds, but do not have a bend
– Behave like saturated fats - Hydrogenated Oils
– Hydrogen synthetically
added to unsaturated fats
to remove double bonds
– Hydrogenation is
incomplete, and some
cis bonds are converted
to trans
What are the reasons that trans fats are added to foods?
– Less perishable
– More solid at room temp.
– Don’t separate
Why is adding trans fats to foods bad for our health?
– Unnatural
– Cannot be digested properly
– Clog arteries
– Cause inflammatory
responses
Imagine that you have a sample of purified phospholipids in a test tube.
a) If you mixed this sample of pure phospholipids with a sample of pure water, what do you think will happen? Explain why this would happen.
– Phospholipids are amphipathic
– Polar heads interact with water on outside
– Non-polar tails hide from water in the inside
Imagine that you have a sample of purified phospholipids in a test tube.
If you mixed a sample of pure fat, rather than phospholipids, with a sample of pure water, what do you think would happen?
Explain why it would be different than what happens with the phospholipids.
- Fats are very hydrophobic (not amphipathic)
- Clump together and separate from water
