CHO Flashcards
What is the role of glucagon in the liver?
To stimulate gluconeogeneis
What is the role of insulin in the liver?
To stimulate glycolysis
The reaction catalyzed by PFK-1 is what important step in the glycolytic pathway?
The rate-limiting reaction
What is metabolism?
The ability to harness energy from various sources and channel it into biological work
What are triglycerides converted to in the blood?
Fatty acids and glycerol
T or F: Most of the carbons of glucose, fatty acids, glycerol, and AA from food are ultimately converted to Acetyl CoA
T
Polydipsia is?
Extreme thirst
What is ketoacidosis?
Excess levels of ketones in the blood
Diabetes type 1 is?
No insulin in blood due to pancreas stopping making it
What is the universal currency of free energy in biological systems?
ATP
Why is energy released in the hydrolysis of ATP?
Energy is released byecause the charge repulsion, resonance and hydration effects make cleaved ATP->ADP is really energetically favorable. ATP is really willing to lose Phosphate group
T or F: The Ribose on ATP is deoxygenated
F (ribose)
What is catabolism?
Breaking down of things
What is anabolism?
Building up of things
Which is more energetic: Glucose 6 phosphate or Glycerol 3 phosphate?
Glucose-6-phosphate
List these in order from high energy to low: Phosphoenolpyruvate, 1,3-BPG, Phosphocreatine
Phosphoenolpyruvate, 1,3-BPG, Phosphocreatine
What shifts the equilibrium of coupled reactions energetically?
ATP hydrolysis
What is the approximate release of free energy for the hydrolysis of ATP to ADP?
7.3 kcal per mole
Electron donating molecules are also known as?
Reducing agents (it itself gets oxidized)
Electron accepting molecules are also known as?
Oxidizing agent (it itself is reduced)
What are the three ways electrons are transferred biologically?
Directly as an electron, in the form of an H atom (two of them), in form of a hydride ion (along with a proton)
Biological oxidation of carbon atoms are also known as?
Dehydrogenation
Describe NAD and FAD in terms of redox
NAD to NADH is promiscuous and very water soluble, transient. Found in B3 (niacin). FAD to FADH2 is usually tightly bound and associated with enzymes in a long lasting way.
What is pellegra?
Niacin deficiency (NAD def.) 4 D’s: dementia, diarrhea, dermatitis, and sometimes death
What is a futile process?
A reaction that uses the product it creates
What are the three general ways metabolic pathways are regulated?
Amounts of enzyme, catalytic activity (feeback inhibition / allosteric / hormonal), and accessibility of substrate
What is rate-limiting and how does it relate to enzymes?
Like highways, dependent on the step before it, reaction is only as fast as slowest step.
Where does fatty acid synthesis happen?
Liver, fat cells
Where does gluconeogenisis occue?
Liver kidney
Where does heme synth happen?
Bone marrow
The HMP shunt occurs where?
Liver, fat, adrenal cortex, mammary gland
AA synthesis and breakdown occurs where?
Liver
Urea synthesis happens where?
Liver
Cholesterol synthesis happens where?
Liver
Steroid hormone synthesis occurs where?
Adrenal cortex, gonads
T or F: Protein synthesis occurs in mature RBC
F
T or F: Krebs and ETC occur in mature RBC
F
What is hormonal regulation?
Chemical messengers are released from one tissue and affects processes in another tissue
What is a keto group?
C-C=O
C-
What is an aldehyde group?
H-C=O
C-
What is a carbohydrate?
Contain an aldehyde or ketone group and a number of hydroxyl groups
Generic names for 3 carbon to 7 carbon sugars
Triose, Tetrose, Pentose, Hexose, Heptose
What is an isomer?
Same chemical formula with different structure
What is an enantiomer?
Mirror image isomers
What is the most common form of glucose?
D-glucose also called dextrose
How do we determine enantiomer type (D or L) for a sugar?
Furthest chiral carbon from the ketone or aldehyde group and if hydroxyl is on left it is L and on right it is D (Lewis structure)
T or F: Glucose and Fructose are isomers
T
What is an epimer?
Only difference is that the position of a hydroxyl group around asymmetric carbon (chiral)
T or F: Glucose and Galactose are epimers
T
T or F: Glucose and Mannose are epimers
T
T or F: Fructose is a ketose
T
What is a reducing sugar?
When an oxygen on an anomeric carbon is not attached to another structure, it can react with other reagents to become oxidized up to carboxylic acid
How do we number carbons in a sugar?
Carbon one is the top carbon in a linear projection, it is the first carbon clockwise from the O group in the ring
What is the anomeric carbon?
The carbon at which the directionality of the hydroxyl group changes the configuration of the ring (usually on the C1 and active reducing carbon)
What is alpha and beta in relation to the anomeric carbon?
Alpha is when the OH is below the ring, Beta is when the OH is above the ring
What type of bonds make carbohydrate chains?
Gylcosidic bonds
What is a gylcosidic bond?
Hydroxyl group on anomeric carbon of monosaccaharide reacts with hydroxyl or amino group of another compound.
What are the two types of glycosidic bonds?
O and N
What is a sugar alcohol?
Lacks an aldehyde or ketone
What is a sugar acid?
The aldehyde at C1 or OH at C6 is oxidized to a carboxylic acid
What is an amino sugar?
An amino group substitutes for a hydroxyl. The amino group may be acetylated.
What do plants store polysaccharides as?
Amylose or amylopectin
Glucose in starch and glycogen are stored with what linkages?
Alpha linkages (1,4 and 1,6)
Amylose has what type of links only?
Alpha 1,4 bonds only
Cellulose has what type of bonds?
Beta 1,4 bonds, cannot be digested
Alpha-amylase breaks what type of bonds?
Alpha 1,4 glucosidase
The pre-form of an enzyme is called a?
Zymogen
Where are 1,6 alpha bonds broken?
In the gut by isomaltase, glucoamylase, lactase, sucrase and so on
What are the two types of simple diffusion?
Direct across membrane or with a channel protein
What is faciliated diffusion?
Co-transport or the like where proteins help to passively move across boundary of cell
Active transport requires?
ATP to move against gradient
T or F: CHOs are moved across the intestinal epithelium
T
T or F: Glucose is more concentrated in the cell than it is in the lumen
T
Describe the process of moving CHOs (glucose) into a cell and out into the extracellular fluid
Glucose is co-transported into cell with Sodium (Sodium is moving from high to low and glucose is moving from low to high). Sodium-potassium ATPase then moves Na back out and allows K into the cell. Glucose can then be transported into EC space
What protein is used in secondary transport of glucose into cells?
SGLT1 (sodium glucose transporter 1)
T or F: Fructose is more concentrated in the lumen than in cells
T (just follows gradient into cells)
Glut 1 is?
In most cells
Glut 2 transports?
Galactose, glucose, and fructose with a low affinity but high capacity
T or F: Glut 2 is a high affinity low capacity tranporter
F, it is low affinity and high capacity
What is the primary function of Glut 2?
Maintain glucose homeostasis and blood sugar levels
Glut 3 is?
High affinity and basal transporter for sugar. Highly concentrated in neurons
T or F: Fructose uses SGLT1
False, Fructose uses Glut 5 exclusively
What glut transporter is insulin dependent? Where is it commonly found?
Glut 4, muscle and adipose
What is Glut 5?
High affinity for fructose
What type of polysac is amylose? glycogen?
Linear, branched
T or F: Polysacs are broken down into monosaccharides before being absorbed
T
What is lactose intolerance? How is it gained?
Hereditary, acquired (insult epithelial cells and temporarily lose ability to digest). Results in bacteria digesting it leading to H2, Lactic acid, Co2, and acetic acid being made leading to bloating, diarrhea and dehydration
How is lactose intolerance tested
Give controlled amount and measure plasma glucose and galactose levels over time. No spike = no lactase = lactose intolerant
Monosaccharide transport is dependent on what enzyme?
Na/K ATPase
Where does glycolysis tend to happen?
Cytosol, but in cells without mitochondria. Exclusively occurs in brain.
What are the two different enzymes responsible for taking glucose to glucose-6-P?
Hexokinase and Glucokinase
Where is hexokinase located?
Most cells
Where is glucokinase found?
Liver and beta cells
Which has a higher affinity for glucose: hexokinase or glucokinase?
Hexokinase
What has a higher Vm: hexokinase or glucokinase
Glucokinase
Compare and contract properties of glucokinase and hexokinase
Hexokinase has high affinity but low max velocity. Glucokinase has low affinity but high max velocity. Basically glucokinase only really works in very high glucose concentrations
What are the three effects of phosphorylating in phys setting?
Net negative charge taps the molecule in cells, Conserves energy in that it is stored in the P bond, marks the molecules for further metabolism (committed to pathway)
