CPPS 303_Coupling of Nutrient Digestion & Absorption_March 5 & 7 2025 Flashcards
What are the three macro-nutrients that require digestion?
Carbohydrates, proteins, and lipids
What is the primary role of digestive enzymes in nutrient absorption?
To break down macro-nutrients into manageable sizes before absorption
Where is iron and folate actively absorbed in the GI tract?
Duodenum
Which macro-nutrients are absorbed in the small intestine?
Carbohydrates, proteins, and lipids
Where is calcium absorbed at the highest rate in the small intestine?
Duodenum
What is the role of the apical Na/bile-salt transporter (ASBT)?
To actively reabsorb bile acids in the terminal ileum
True or False: Cobalamin (vitamin B12) is absorbed in the ileum.
True
What is required for vitamin B12 absorption in the ileum?
Binding of vitamin B12 with intrinsic factor
What type of digestion do proteins require?
Luminal and brush border digestion
What are the end-products of luminal carbohydrate digestion?
Maltose, maltotriose, α-limited dextrins
Fill in the blank: α-amylase cannot digest plant fiber because it is connected by _______ linkages.
β-1,4
What types of carbohydrates are composed of two monosaccharides?
Disaccharides
What are the main components of sucrose?
Glucose and fructose
What are the three integral membrane brush border proteins involved in carbohydrate digestion?
Lactase, glucoamylase (maltase), and sucrase-isomaltase complex
What transporter is required for the apical absorption of glucose and galactose?
SGLT1
What is the primary function of brush border proteases in protein digestion?
To digest oligopeptides into smaller peptides and amino acids
Which transporter is used for the absorption of tripeptides and dipeptides?
H/oligopeptide co-transporter named PepT1
What is the predominant form of dietary lipid in the human diet?
Triacylglycerols
What is the key step in lipid digestion that occurs in the duodenum?
Emulsification
What proteins mediate fatty acid uptake during lipid absorption?
Fatty acid translocase (CD36), intestinal Fatty Acid Binding Protein (FABP), Fatty Acid Transport Protein (FATP)
How are chylomicrons secreted into the body after lipid absorption?
They are secreted into the interstitial space and move toward the lymphatic system
What is the role of Niemann-pick C-1 like 1 (NPC1L1) protein?
To mediate the absorption of cholesterol
True or False: Short chain fatty acids are packaged in chylomicrons.
False
