Bio-Biochem

Question 1

Where is Glut1 express?

Answer 1

Throughout body, esp common in fetal tissue and RBC.
It is also upregulated in cancer cells.

Question 2

Function of Glut1

Answer 2

Low-level baseline glucose intake
- Upregulated in low blood sugar level
- Downregulated in high blood sugar level

Question 3

Where is Glut2 expressed?

Answer 3

Liver cells, pancreatic beta cells, kidney cells

Question 4

Function of Glut2

Answer 4

Bidirectional transporter, necessary for cells carrying out gluconeogenesis.

Question 5

What hormone do pancreatic beta cells secrete?

Answer 5

Insulin; to monitor blood glucose levels.

Question 6

Which type of glucose receptor do pancreatic beta cells express?

Answer 6

Glut2

Question 7

Where does Glut3 express?

Answer 7

Neurons and placenta

Question 8

Function of Glut3

Answer 8

High-affinity transporter, transporting glucose effectively when blood glucose levels are low.

Prioritize providing glucose for important area (nervous system, fetus)

Question 9

Where does Glut4 express?

Answer 9

Non-smooth muscle (skeletal and cardiac muscle) & adipose tissue

Question 10

Function of Glut4

Answer 10

Store glucose in skeletal muscle, cardiac muscle and adipose tissue when a surplus of glucose is present in blood.

Question 11

Which hormone regulates Glut4?

Answer 11

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.

Question 12

Diabetes type 1 vs type 2

Answer 12

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.

Question 13

2 strategies through which glucose provides energy (synthesizing ATP)

Answer 13

1. Substrate-level phosphorylation
2. Oxidative phosphorylation (electron transport chain)

Question 14

Shifting oxygen-hemoglobin dissociation curve

Answer 14

Right shift: Hemoglobin has less affinity for oxygen
Left shift: Hemoglobin has greater affinity for oxygen

Question 15

2 forms of hemoglobin

Answer 15

Taut/ Tense (T) form: low affinity for oxygen

Relaxed (R) form: high affinity for oxygen

Question 16

Bohr effect on hemoglobin

Answer 16

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.

Question 17

Types of enzymes

Answer 17

Question 18

Isoenzyme / Isozyme

Answer 18

Different forms of enzymes that catalyze the same rnx but with varying efficiency.
They can be distinguished by their electrophoretic mobilities.

Question 19

Glycoglysis

Answer 19

Converts glucose into pyruvate through a series of enzymatic rnx.

Question 20

The average molecular weight of an amino acid

Answer 20

110 Dalton

Question 21

T/F
There is no viable autosomal monosomy.

Answer 21

True

Question 22

Name some viable autosomal trisomies

Answer 22

Trisomy 21: Down syndrome
Trisomy 18: Edward syndrome
Trisomy 13: Patau syndrome

Question 23

Surfactant

Answer 23

Amphipathic molecules that reduce the surface tension of a liquids.

• Detergents belong to surfactants. Their amphipathic structure allows them to denature proteins (SDS).

Question 24

Pulmonary surfactant

Answer 24

Its absorption to the water-alveolar interface reduces surface tension in alveoli, allowing them to remain inflated when the lung is compressed during respiration.

Question 25

What cells produce sperm and where?

Answer 25

Sperm is produced by Sertoli cells of seminiferous tubules.

Question 26

T/F
Estrogen inhibits bone resorption.

Answer 26

True

Question 27

Succinyl-CoA synthetase

Answer 27

Catalyze the reversible conversion of succinyl-CoA to succinate.

Question 28

Large amounts of protein are found in the urine of a patient. Based on this info, which portion of the nephron is most likely malfunctioning?

Answer 28

Glomerulus.
Because in healthy people, the structure of glomerular capillaries prevents the entry of large molecules (such as protein) into the filtrate.

Question 29

The order in which filtrate passes through the tubular regions of a nephron.

Answer 29

Bowman’s capsule -> proximal tubule -> loop of Helen -> distal tubule -> collecting duct