Week 3 Day 2 Biochemistry Flashcards
Lactose is cleaved into glucose and galactose by which enzyme?
lactase
In going from pyruvate to acetyl CoA, how many molecules of CO2 are generated from 2 pyruvate?
2 CO2
Though we produce some ATP from glycolysis, and some ATP from the kreb’s cycle, where do we ultimately produce the most ATP and how?
The electron transport chain through oxidative phosphorylation
Reduced intermediates, NADH and FADH2, produced from glycolysis, pyruvate oxidation, and the kreb’s cycle, go into the ETC to produce ATP
Is glycolysis an aeorbic or anaerobic process?
Glycolysis is anaerobic. It does not consume any O2 or produce any CO2.
Sucrose is made of which two sugars?
Glucose + Fructose
Between omega 3 and omega 6 fatty acids, which ones will be more fluid in our cell membranes?
Omega 3 fatty acids because the melting point is lower.
How many ATP’s are produced in the Kreb’s cycle?
2
Besides glycolysis, name 3 other fates of glucose.
1. Glucose can be stored as glycogen
2. Glucose can be broken down in to a 3 carbon glycerol to aid in making plasma membranes and storing fat
3. We can pull a carbon off of the glucose to make a pentose. This is the path in which we can synthesize pyrimidines and purines as well make DNA and RNA.
Common name for omega 6 fatty acid
linoleic acid
T or F: D-Ribose is an aldohexose.
False;
D-Ribose is an aldopentose
T or F: In general, saturated fats are solid at room temperature.
True
*Think of bacon grease after cooking, lard*
Is D-Fructose an aldehyde or a ketone?
A ketone, known as a ketohexose
During one turn of the kreb’s cycle, how many CO2s do we lose or kick off?
2
**Remember, this is for ONE turn of the kreb’s cycle, from ONE Acetyl CoA from ONE pyruvate. We generate TWO molecules of pyruvate for every ONE glucose.**
T or F: Fatty acids having one or more C-C double bonds are termed unsaturated.
True
List the products of glycolysis.
For each glucose (6 carbon molecule)
we produce:
Two 3 carbon molecules of pyruvate
2 ATP
2 NADH
Which molecule can we use to restore an oxaloacetate from the citric acid cycle?
pyruvate
What is the purpose of an enzyme?
to speed up reactions
(S) - substrate
(E) - enzyme
(P) - product
S+E → ES → EP → E+P
In the prcosess of glycolysis, glucose (a 6 carbon molecule) splits into two 3 carbon molecules. This can result in 2 pyruvates or 2 ________, which will be very important in making plasma membranes and storing fats.
glycerol - 3 - p
In regards to fatty acids, fatty acids with longer carbon chains will have a higher or lower melting point?
higher
Common name for omega 3 fatty acid
a-linolenic acid
Do trans double bonds cause kinks?
No
*think of fake butter, trans fatty acids/trans fats”
For every ONE glucose molecule, we kick off ___ CO2s from pyruvate to Acetyl CoA, and ___ CO2s during the kreb’s cycle?
2; 4
What is an enzyme?
A catalyst made of protein
T or F: Even though D-Fructose is a ketone, and D-Glucose, D-Mannose, and D-Galactose are aldehydes, all are hexoses.
True;
All 4 molecules are hexoses.
T of F: Enzymes have the ability to change the energetics of a reaction.
False;
Enzymes do not add any energy and do not take energy out of the reaction.
What is the Respiratory Exchange Quotient (REQ) for glucose and palmitate?
CO2 produced/exhaled : O2 inhaled
Glucose: 6/6 = 1.0
Palmitate 16/23 = 0.7
Lactose is made of which two sugars?
Glucose + Galactose
Besides D-Glucose, name 2 additional important aldehydes in our diet.
D-Galactose
D-Mannose
*There are 16 total aldehydes of this kind, 8 D and 8 L. We are only discussing D-Glucose, D-Galactose, and D-Mannose*
Are enzymes regulated?
Yes, enzymes are regulated. They “turn on” or “turn off” based off of what our body needs.
If a fatty acid has no C-C double bonds, is it saturated or unsaturated?
saturated
Can fatty acids enter directly into the TCA cycle?
Not directly, no. A fatty acid chain can be broken down into 2 carbons a time → these can be added to a
Coenzyme A to make an acetyl CoA → which can then enter the Kreb’s cycle.
Is D-Glucose an aldehyde or a ketone?
An aldehyde, known as an aldohexose
Explain how omega 3 and omega 6 FA are named as such.
The carbon chains of the fatty acids are named with the carboxylic carbon as #1. If you count backwards from the end of the chain (omega), the first cis double bond will be either 3rd (omega 3) or 6th (omega 6) from the omega of the chain.
Does this molecule represent an aldohexose or ketohexose?
an aldohexose
How many carbons does D-Ribose have?
5 carbons
T or F: Enzymes catalyze reactions in only one direction.
False;
Enzymes catalyze a reaction in both directions.
For primarily naming sugars and amino acids, we will use ___ and ___ to describe “right” and “left.”
D and L
D (dexter) - right
L (laevos) - left
Where in the cell does the TCA cycle occur?
the mitochondria
D-Glucose is ____ handed structure.
right
the D is for dexter or “right”
What is an active binding site?
The place where a substrate (S) will bind to the enzyme, and where all of the enzymatic activity occurs.
What molecule do we end up with when we reduce NAD+?
we gain a hydrogen, so NADH
Remember OIL RIG acronym
Oxidation is loss (of electrons), reduction is gain (of electrons)
In which part of the mitochondria does the TCA cycle occur?
mitochondiral matrix
Where does glycolysis occur in the cell?
cytoplasm
Would you suspect a lower pH in the inner membrane space or the matrix of the mitochrondria?
Inner membrane space
H+ is pumped out of the matrix into the inner membrane space, contributing to membrane potential.
Why would we ever need to restore an oxaloacetate from pyruvate?
Whenever we take something out of the cycle, we have basically reduced our oxaloacetate and lost a net oxaloacetate.
i.e. Succinyl CoA → porphyrins → heme
a-Ketoglutarate → glutamate → purines
Does this molecule represent an aldohexose or ketohexose?
A ketohexose
Where is fructose primarily processed?
The liver
Sucrsose can be cleaved into glucose and fructose by which enzyme?
sucrase
What does the liver like to do with fructose?
The liver likes to make glycerol out of fructose.
During pyruvate oxidation, 1 carbon is cleaved from pyruvate (3 carbon molecule) to form Acetyl CoA (2 carbon compund). What happens to the cleaved carbon?
This becomes a CO2.
Glycerol is the “backbone” for which type of molecule?
A triglyceride.
A triglyceride has a glycerol backbone with 3 fatty acids
In the citric acid cycle, we add Acetyl CoA (2 carbons) to __________(4 carbons) to form Citrate/Citric Acid (6 carbons).
Oxaloacetate
T or F: Under aerobic conditions, the pyruvate produced from glycolysis is converted to lactic acid.
False;
Under aerobic conditions, each pyruvate is converted into Acetyl CoA to feed into the Kreb’s cycle.
Pyruvate is reduced to lactate under anerobic conditions.
How do enymes catalyze a reaction?
By lowering the transition energy of the reaction, making the reaction go much faster.
Adding double bonds to a fatty acid greatly _________ the melting point.
reduces
The more cis double bonds, the more kinks in the fatty acids, the less tightly the FA chains can be packed together.
When glucose enters the cell for glycolysis, it is immediately phosphorylated to make _______________.
glucose 6 phosphate
In the Michaelis Mentin equation, what is Km<span>?</span>
Km is the substrate concentration at which the reaction rate is at half maximum
Km = VMax/2
In the Michaelis Mentin equation, what is Vmax?
Vmax is the maxmimal velocity (rate) a reaction can achieve at an infinite concentration of substrate.
*The enzyme is completely saturated with substrate*
Is the Kreb’s cycle anabolic, catabolic, or amphibolic?
Amphibolic
Michaelis Menten equation
V = Vmax * S / Km + S
