Hemoglobin
What is the difference between T and R states of hemoglobin? Does myoglobin experience these shifts as well?
T- tense state, low oxygen affinity, favors oxygen release
R- rest state, high oxyge affinity, favors oxygen binding
NO - myoglobin only has one polypeptide subunit (one oxygen binding site) and does not experience cooperative binding
What are the structural differences between aldoses and ketoses? Give an example of each
Aldose: has an aldehyde group, carbonyl group is usually on carbon 1, ex: glucose
Ketose: has a ketone group, carbonyl group is usually on carbon 2, ex: fructose
Explain the structure of a fatty acid
-carboxyl group
-long hydrocarbon chain
True or false: Cellulose and chitin are polymers of amino acids.
False. Cellulose is made of glucose; chitin is made of modified glucose units called N-acetylglucosamine.
explain the differences between hemoglobin and myoglobin (function, location, struture, oxygen-binding curve)
hemoglobin: oxygen transport from lungs to tissues, found in rbc's, 4 polypeptide subunits, sigmoidal.
myoglobin, oxygen storage in muscles, found in muscle cells, 1 polypeptide subunit, hyperbolic
Compare D vs. L sugars
Compare alpha vs. beta sugars
D: -OH on the right
L: -OH on the left
Alpha: anomeric -OH is down
Beta: anomeric -OH is up
18:1(Δ9)
What enzyme breaks down amylose, and what disaccharide can result from its breakdown?
Amylase, maltose
What is BPG? What does it do?
2,3-BPG
-negatively charged
-binds to positively charged amino acids central pocket of deoxygenated hemoglobin
- binding stabilizes T -state (tense), causes lower oxygen affinity so hemoglobin releases more readily
List the three disaccharides your slides cover and their respecitve monomors, glycosidic linkages, and if they are reducing or non-reducing.
Maltose: glucose + glucose, a(1-4) GL, reducing
Lactose: galactose + glucose, b(1-4) GL, reducing
Sucrose: fructose + glucose, a(1-2) GL, non-reducing
non-saturated: at least one c-c double bond, bendy chain, less tightly packed.
True or false: Cholesterol is a fatty acid.
False. Cholesterol is a sterol.
What happens when oxygen binds to one of hemoglobin's iron atoms?
-heme group becomes flatter
-hemoglobin shifts from T to R state
-the other three heme groups bind more readily (positive coopertativity)
List the four polysaccharides your slides cover and their respective functions and glycodisic linkages.
Amylose: plant energy storage, a(1-4) GL
Amylopectin: plant energy storage, a(1-4) GL
Glycogen: animal energ storage, a(1-4) GL
Cellulose: plant cell wall structural support, b(1-4) GL (we cannot digest these beta GL - no cellulase)
What is the difference between cis and trans fatty acids?
cis: hydrogens around double bond are on same side, chain bends
trans: hydrogens around double bonds are on opposite sides, chain is straighter
Why does lactose intolerance cause diarrhea and intestinal cramping?
Undigested lactose increases the osmotic movement of water into the intestine, and its fermentation by gut bacteria produces gas and other compounds that contribute to symptoms.
Explain the differences between fetal hemoglobin and adult hemoglobin. Why is this so?
HbF - 2 gamma subunits - fewer positively charged amino acids, BPG binds less strongly, less stabilized in T-state, higher oxygen affinity, lower P50
HbA- 2 beta subunits
HbF's higher oxygen affinity allows the fetus to pull oxygen from the mother's blood across the placenta
Of the four polysaccharides you learned about, which two are branched? How often do they branch? What type of GL do the branch points use?
Amylopectin: branches every 24-30 units, a(1-6) GL
Glycogen: branches every 8-12 units, a(1-6) GL, this high branching allows more enzymes to break it down
How does fatty acid length impact melting point?
Longer fatty acid chains have higher melting points because they have stronger overall dispersion forces.
Shorter chains generally have lower melting points.
What is HbA1c?
non-enzymatic
helps with long-term monitoring of blood-glucose levels