Biochemistry week 13 Flashcards
What is the chemical formula of Carbohydrates
Cn(H2O)n
What are carbohydrates composed of
Monasacharide building blocks
Name the 4 types of Carbohydrates
- Monosaccharides
-Disaccharides
-Oligosaccharides
-Polysaccharides
What are oilgomonasacchardies made of
- 3-10 monosaccharides
What are polysaccharides made of
- Long chains of monosaccharides conected by glycosisidc bonds
Name 3 monosaccharides
- Glucose
-Galactose
-Frcutose
Name 2 disaccharides
-Sucrose
-Lactose
Name 3 polysaccharies
- Cellulose,starch,glycogen
What do simple carbohydrates consists of
-Monosaccharides and disaccharides
What does comples carbohydrates consists of
- Polysaccharides
What are Aldoses
- Carbohydrates with an aldehyde group as the most oxidized functional group.
What are Ketoses
-Carbohydrates with a ketone group as the most oxidized functional group.
What is the first step of Carbohydrate digestion(Digestion of Polysaccharides and Disaccharides)
- ## Breaking down the polymers into simpler soluble form
Where does digestion of carbohydrates start
- In the mouth .
Where the saliva has a slighly acidic pH of 6.8 and contains salivary amylase
What is the overview name of the 2nd step of carbohydrate metabolism
- Conversion to monosaccharides
Explain how the Di + polysaccharides are converted to Monosaccharides
+ examples of enzymes
- Enzymes in the intestine break down the di + polysaccharides to monosaccharides by intestinal saccharides.
Maltases: Hydrolyze di- and trisaccharides.
Specific Disaccharidases:
Sucrase-isomaltase: Breaks sucrose and isomaltose.
Lactase (β-galactosidase): Breaks lactose.
Trehalase: Breaks trehalose.
What is the final step of digestion of carbohydrates
- They are absorbed in the intestine via
-Passive diffusion
-Facilitated diffusion
-Active transport
What is the name of the 2 intestinal transportors for glucose uptake
-Sodium Dependent (SGLT1)
-Sodium independent (GLUT2)
Explain the sodium-depenedent (SGLT1) transporter for glucose
Sodium-Dependent (SGLT1):
Primary transporter for glucose and galactose from the small intestine.
Uses sodium (Na⁺) gradient for active transport
Explain the sodium independent (GLUT2) transporter for glucose uptake
- Transports glucose into intestinal cells during glucose-mediated translocation
- Plays a role in glucose uptake into the portal circulation
How is fructose absorbed in the intestine
Via GLUT5, which is a specialised transported with a high affinity for fructose
What is the mechanism of SGLT1( sodium dependent) for the absorption of Na:
-The role of Na gradient
-Maintaining the Na gradient (pump)
- Role of Na⁺ Gradient:
The intestinal lumen has a higher Na⁺ concentration compared to epithelial cells, enabling Na⁺-dependent glucose transport.
Maintaining the Na⁺ Gradient:
A Na⁺, K⁺-ATPase pump on the basolateral membrane actively removes Na⁺ from epithelial cells into the extracellular space, preserving the Na⁺ gradient.
Glucose Absorption:
After uptake via SGLT1, glucose is transported into the bloodstream.
What is the function of GLUT transporters
Facilitate passive diffusion of glucose and fructose from areas of higher to lower concentration.
Explain the model for transport and how GLUT glucose transportes work
Binds glucose on one side of the membrane, undergo a conformational change , and then release it on the other side of the membrane
Where is GLUT 1 found
various tissues especially erythrocytes
Where is GLUT 2 found
- Intestine,pancrease,liver and kidney
Where is GLUT 3 found
- Neurons and itestine
what type of transporter is GLUT 4 and where is it found
Insuline-sensitive receptor
- In skeletal muscles and adipose tissue
What type of transporter is GLUT 3
- High-affinity glucose transporter
Where is GLUT 5 found
- intestine
-kidney
What is the purpose of SGLT inhibitors
- They are drugs used to lower blood glucose levels in patients with type 2 diabetes
Explain the mechanism of SGLT inhibitors
These drugs inhibit the Na+-coupled glucose transporter SGLT2 in the kidneys.
This prevents the reabsorption of filtered glucose, causing glucose to be excreted in the urine.
Where does the Pentose Phosphate Pathway occur
- In cytoplasm
What is the name of the 2 phases that the pentose phosphate pathway consits of
- Oxidative phase
-Non-oxidative phase
Explain what happens in the oxidative phase
- Irreversible reactions
-Producing 2 NADPH , ribulose-5-phospahte and CO2 per glucose-6-phosphate
Explain what happens in the Non oxidative phase
+ what it requires
-Reversible reactios:
That converts 5 carbon sugars into intermediates of glycolysis or gluconeogenesis
- Requires transketolase, which depends on thiamine
What is NADPH required for
- Fatty Acid and cholesterol biosynthesis
-Steroid hormone biosynthesis
What are the 4 sites of the Pentose Phosphate pathway
- Liver,adipose tissue, RBCS, adrenal cortex
If NADPH acts as an inhibitor what does it inhibit in the PPP
- Inhinits glucose-6-phosphate dehydrogenase
What does thiamin deficiency lead to in the PPP
- Abnormal transketolase activity
What is the definition of the reactive oxygen species
- Where oxygen can accept single elctrons to form reactive oxygen species including:
-Superoxide
-Hydrogen peroxide
-Hydroxyl radical
What type of damage can Reactive oxygen species do
- ROS can cause damage to lipids,proteins leading to free radical damage
What can help to protect against Reactive oxygen species
-Enzymes
-Vitamins such as C and E which protect against radical damage
How does the structure of NADPH differ from NADH
- The presence of a phosphate group
What are the primary uses of NADPH
- Biosynthesis
-Phagocytosis
-Defense againts the reactive oxygen species - Antioxidant defense(Hydrogen Peroxide reduction)
What is G6PD deficiency
- It is a hereditary condition causing hemolytic anemia due to the inability to detoxify oxidizing agents
Whos is G6PD deficicency most common in
Males
What may G6PD deficiency provide protection against
Malaria
Name the 4 main roles of G6PD in RBC
-Produces NADPH,
-Decreased NADPH
-Oxidative damage forms Heinz bodies
Rigid RBCs are removed by macrophages in the spleen and liver.
Name the 3 precipitating factors in G6PD deficiency
-Oxidant Drugs
-Favism
-Infections
What are symptoms of G6PD deficiency
- May present as dark urine
-Recurrent hemolysis after exposure to triggers
Give examples of Oxidant drugs as a precipitating factors
- Antibitoics
-Antipyretics
What is producing NADP important for as a role of G6PD deficiency
- Maintaining reduced glutathione
What does decreasing NADPH as a role of G6PD do
- Reducsed detoxification of free radicals and peroxides
