Bio-Biochem Flashcards
(29 cards)
Where is Glut1 express?
Throughout body, esp common in fetal tissue and RBC.
It is also upregulated in cancer cells.
Function of Glut1
Low-level baseline glucose intake
- Upregulated in low blood sugar level
- Downregulated in high blood sugar level
Where is Glut2 expressed?
Liver cells, pancreatic beta cells, kidney cells
Function of Glut2
Bidirectional transporter, necessary for cells carrying out gluconeogenesis.
What hormone do pancreatic beta cells secrete?
Insulin; to monitor blood glucose levels.
Which type of glucose receptor do pancreatic beta cells express?
Glut2
Where does Glut3 express?
Neurons and placenta
Function of Glut3
High-affinity transporter, transporting glucose effectively when blood glucose levels are low.
Prioritize providing glucose for important area (nervous system, fetus)
Where does Glut4 express?
Non-smooth muscle (skeletal and cardiac muscle) & adipose tissue
Function of Glut4
Store glucose in skeletal muscle, cardiac muscle and adipose tissue when a surplus of glucose is present in blood.
Which hormone regulates Glut4?
Insulin, secreted by pancreatic beta cells.
Insulin upregulates the expression of Glut4 in plasma membrane, increasing glucose uptake into cells and reducing blood sugar levels.
Diabetes type 1 vs type 2
Diabetes type 1:
Autoimmune rnx destroying the pancreatic beta cells -> cannot secrete insulin
Diabetes type 2:
Insulin resistance
Frequent high blood glucose levels lead to frequent insulin spikes, causing the cells to be desensitized toward insulin.
2 strategies through which glucose provides energy (synthesizing ATP)
- Substrate-level phosphorylation
- Oxidative phosphorylation (electron transport chain)
Shifting oxygen-hemoglobin dissociation curve
Right shift: Hemoglobin has less affinity for oxygen
Left shift: Hemoglobin has greater affinity for oxygen
2 forms of hemoglobin
Taut/ Tense (T) form: low affinity for oxygen
Relaxed (R) form: high affinity for oxygen
Bohr effect on hemoglobin
Increase in CO2 leads to higher concentration of H+ because CO2 reacts with H2O to form H2CO3, which then dissociates into HCO3- and H+. This decreases pH.
H+ favors T form of hemoglobin, causing it to have less affinity for oxygen, shifting oxygen-Hb dissociation curve to the right.
Types of enzymes
Isoenzyme / Isozyme
Different forms of enzymes that catalyze the same rnx but with varying efficiency.
They can be distinguished by their electrophoretic mobilities.
Glycoglysis
Converts glucose into pyruvate through a series of enzymatic rnx.
The average molecular weight of an amino acid
110 Dalton
T/F
There is no viable autosomal monosomy.
True
Name some viable autosomal trisomies
Trisomy 21: Down syndrome
Trisomy 18: Edward syndrome
Trisomy 13: Patau syndrome
Surfactant
Amphipathic molecules that reduce the surface tension of a liquids.
- Detergents belong to surfactants. Their amphipathic structure allows them to denature proteins (SDS).
Pulmonary surfactant
Its absorption to the water-alveolar interface reduces surface tension in alveoli, allowing them to remain inflated when the lung is compressed during respiration.
