LIPIDS: Notes, Homework, Tophat Flashcards
A silicon atom has _____ for an oxygen atom than for another silicon atom, which is why the bond dissociation energy for SiO2 is ____as compared to that of Si-Si
more affinity, greater
In eukaryotes synthesizing a lipid involves ____, and making fatty acids involves _______.
Golgi complex, ER
Are waxes a class of membrane lipid
no
What do glycolipids and triacylglycerols have in common?
both contain amphipathic fatty acids
what is a lipid that is a phospholipid with two acids and a glycerol platform
phosphoglyceride
what is a lipid that is a phospholipid with one fatty acid and a sphingosine platform
sphingolipid
what is the lipid with one fatty acid; found in animal cell membrane
glycosphingolipid
what is the lipid with a glycolipid with two fatty acids; found in plant cell membranes
glycoglycerolipid
T/F: Lateral diffusion is common but transverse diffusion is rare
true
Which of the following is the hydrogen bond?
blue dotted line, water connecting to the open orbitals of the oxygen
Where do you usually start counting if we want to determine a FA’s number designation
By the end with carboxylic acid, double bond connected to carbon
If we wanted to synthesize a lipid with the greatest/ highest possible melting point, we should pick
lauric acid (12:0), more carbons but no double bonds
-we don’t want 12:3, 10:1, 8:0
What do phospholipids and steroids have in common?
both have naturally-occurring membrane lipids
-NOT
-both are polar molecules stored within adipocytes
-both have sphingosine and an alcohol group
-both have cyclic structure with a steroid nucleus
T/F: Membranes are stabilized by covalent bonds between phospholipids
false- noncovalent bonds
Polyphosphoinositides are a type of phospholipid. They comprise about 1% of the inner (cytoplasmic) leaflet of the plasma membrane but are absent from the outer (extracellular) leaflet. This is an example of:
membrane asymmetry
True or false: Molecules moving via simple diffusion require protein transporters.
false
Glycosphingolipid GM3 is found in both the outer (extracellular) and inner (cytoplasmic) leaflets of the malaria parasite’s plasma membrane. GM3’s negative charge is countered by positively-charged sodium ions in the interstitial space, but retained within the cell. This is an example of:
membrane polarity
What is this transport: Polar nucleosides moving with the concentration gradient
Facilitated diffusion
What type of transport: Cardiolipin (a phospholipid) moving from one membrane leaflet to the other
Transverse diffusion
What type of transport: Water moving from low (1%) to high (5%) salt concentration
Osmosis
Biomolecules are ____ based polymers
carbon
What is a polymer?
a large molecule composed of many repeating monomers
monomer must be _____ in a polymer
interlinked/ directly connected to one another
What are the major elements of life
CHNOPS
what are the three molecules that are the majority of atoms in an organism?
carbon, hydrogen, and oxygen
Why is carbon so versatile?
- has an open outer shell, stops at the second shell with 6 electrons
-has an affinity for oxygen/ good bond dissociation
-has a good bond dissociation energy
-decent electronegativity
what are covalent bonds?
sharing of electron pairs between atoms, strong bonds
what are noncovalent interactions?
variations in electromagnetic interactions within a molecule or between molecules, weaker than covalent bonds
compare and contrasts the cell wall/ membrane
cell wall:
- present in all prokaryotic and some eukaryotic cells
-think/ rigid structure, primary made from carbs
membrane:
-present in ALL pro/eukaryotic cells
-thin flexible structure composed of lipids
-important for signal transduction pathway
what is an organelle? what are the made of?
a membrane-bound compartment within a eukaryotic cell, composed primarily of lipids
-allow biochemical functions to be sequestered
Describe the nucleus
-largest organelle
-where DNA is synthesized and stored
-double membrane, outer membrane punctuated with pores
-important in eukaryotic transcription
describe the Mitochondrion
the primary site of ATP generation
-important for cellular respiration
-double membrane, inner membrane, is highly invaginated(folded)
-retains own genome
describe the ER
-resides in the cytoplasm, single membrane
-Unsaturated FA synthesis and translation in eukaryotes
Describe the rough ER
has ribosomes, helps synthesize and process proteins
Describe the smooth ER
lacks ribosomes, helps process exogenous chemicals
describe the Golgi complex
-stacked, flatted membranes in one single membrane
-helps sort and process proteins (carbs may be added here)
-Synthesis of some LIPIDS
-proteins transported into the golgi by transport vesicles
What are the lipid monomers
fatty acids
In clinical trials, the drug Troglitazone has shown promise as an oral medication for people with Type II diabetes. Troglitazone stimulates the phosphorylation of protein kinase B (Akt), thereby lowering blood-sugar levels. Consequently, this drug stimulates the insulin signal transduction pathway by:
activating the pathway’s effector molecule
GLUT4 is classified as an insulin-responsive transporter because it:
only inserts itself in the membrane when the insulin signal transduction pathway is active
The term “lipase” describes enzymes that catalyze the hydrolysis / breakdown of fats. Would it be appropriate to use the term “lipase” if the enzyme cleaved a different biomolecule, like proteins?
No, it would not be.
What do gastric lipase and pancreatic lipase have in common?
Both generate free fatty acids via cleavage.
True or false: Insulin stimulates the adipose tissue to hydrolyze / break apart triacylglycerols.
This is false.
Shortening of the hydrocarbon chain happens In which step of the β-oxidation pathway?
Step 4 (thiolysis by coenzyme A)
True or false: The human body can metabolize unsaturated fatty acids.
This is true.
What do the beta-oxidation pathway and ketolysis have in common?
Both generate acetyl CoA, which enters the citric acid cycle.
What is this type of transport: Lipophilic estradiol moving against the concentration gradient
active transport with a pump
what is this type of transport: Carbon monoxide gas (CO) moving with the concentration gradient
simple diffusion
what is this type of transport: Zinc ions (Zn2+) moving with the concentration gradient
facilitated diffusion with a channel
What do transporters and receptors have in common?
Both are integral membrane proteins that facilitate cellular functions.
The drug Raloxifene is often prescribed to post-menopausal women for the prevention of breast cancer. Raloxifene attaches to the estrogen receptor, thereby preventing the ligand estradiol from binding. Consequently, this drug suppresses the estrogen signal transduction pathway by
Competing with the primary messenger
Shutting down the insulin signal transduction pathway involves dephosphorylating:
The second messenger
Which statement about metabolic pathways is true?
Metabolic pathways share intermediates, but not regulatory enzymes.
True or false: Digestive enzymes break noncovalent bonds within lipid-containing foods.
false
Dietary lipid digestion involves gastric lipase, bile salts, and pancreatic lipase.
For each molecule listed, indicate where in the human body it participates in digestion.
-gastric lipase
-bile salts
-pancreatic lipase
-stomach, small intestine, small intestine
The correct order for the series of repeating reactions in the β–oxidation pathway is:
Oxidation, hydration, oxidation and thiolysis
(even molecule) Metabolizing the fatty acid shown below would involve _______. The final thiolysis products would be ________
peroxisome and mitochondria and two acetyl CoA
Does the β–oxidation pathway involve any coenzymes?
Yes, it involves both NAD+ and FAD.
Glycerol metabolism generates glyceraldehyde 3-phosphate, a product that can enter cellular respiration via _______
glycolysis
Lengthening of the hydrocarbon chain happens In which step of the fatty acid synthetic pathway?
step 1 condensation
True or false: The human body can synthesize trans-unsaturated fatty acids.
this is false
Of the four major classes of lipids, which two can be synthesized by most cells in the human body?
Phospholipid and glycolipid
True or false: The human body can metabolize unsaturated fatty acids.
this is true
What do the beta-oxidation pathway and ketolysis have in common?
Both generate acetyl CoA, which enters the citric acid cycle
True or false: Insulin stimulates the adipose tissue to hydrolyze / break apart triacylglycerols.
false
What do gastric lipase and pancreatic lipase have in common?
Both generate free fatty acids via cleavage.
Shortening of the hydrocarbon chain happens In which step of the β-oxidation pathway?
Step 4 (thiolysis by coenzyme A)
