Seminar 1 Flashcards
(12 cards)
Name the essential amino acids
Histidine
• Isoleucine
• Leucine
• Lysine
• Methionine
• Phenylalanine
• Threonine
• Tryptophan
• Valine
Name the essential fatty acids
Linoleic acid (omega-6)
Alpha-linolenic acid (omega-3)
Can you summarise the full digestion of a polysaccharide into monosaccharides? Include all the locations and the enzymes that break down polysaccharides into monosaccharides.
Mouth:
• Enzyme: Salivary amylase
• Breaks starch into maltose and smaller polysaccharides.
• Stomach:
• Acidic pH inactivates amylase; no carbohydrate digestion.
• Small Intestine (duodenum):
• Enzyme: Pancreatic amylase
• Breaks remaining polysaccharides into disaccharides.
• Small Intestine (brush border enzymes):
• Maltase → maltose → 2 glucose
• Lactase → lactose → glucose + galactose
• Sucrase → sucrose → glucose + fructose
Can you summarise the full digestion of a protein into an amino acid? Include all locations and enzymes.
Stomach:
• Enzyme: Pepsin (activated by HCl from pepsinogen)
• Breaks proteins into polypeptides.
• Small Intestine:
• Pancreatic enzymes:
• Trypsin, chymotrypsin – cleave into short peptides
• Carboxypeptidase – cleaves terminal amino acids
• Small Intestine (brush border):
• Aminopeptidase, dipeptidase – complete digestion into individual amino acids
Can you summarise the full digestion of fat into it’s final structure ready to be absorbed? Include all locations and enzymes involved and other factors.
Mouth: Minimal digestion by lingual lipase.
• Stomach: Gastric lipase starts fat breakdown.
• Small Intestine:
• Bile salts (from liver/gallbladder) emulsify fats into smaller droplets.
• Pancreatic lipase breaks triglycerides into:
• Monoglycerides + 2 free fatty acids
• These form micelles with bile salts for absorption.
What is the basic biochemical structure of a monosaccharide
Basic unit of carbohydrates.
• General formula: C₆H₁₂O₆.
• Contains carbon (C), hydrogen (H), and oxygen (O).
• Has a carbon backbone (usually 5–6 carbons), with hydroxyl groups (-OH) and a carbonyl group (C=O).
What is the basic biochemical structure of a triglyceride
Triglyceride (fat molecule):
• Made of 1 glycerol + 3 fatty acids.
• Glycerol: 3-carbon alcohol (C₃H₈O₃).
• Fatty acids: long hydrocarbon chains with a carboxylic acid group (-COOH).
• Contains C, H, O atoms.
What is the basic structure of an amino acid
Amino Acid:
• Basic unit of proteins.
• Structure: central carbon (C) attached to:
• an amino group (–NH₂)
• a carboxyl group (–COOH)
• a hydrogen atom
• a unique side chain (R group)
• Contains C, H, O, N.
Summarise the absorption of monosaccharides into the SI
Monosaccharides:
• Glucose & Galactose:
• Absorbed via SGLT1 (sodium-glucose co-transporter)
• Fructose:
• Absorbed via GLUT5 (facilitated diffusion)
Summarise the absorption of amino acids into the SI
Active transport via Na⁺-dependent transporters
Summarise the absorption of fatty acids and monoglycerides into the SI
Diffuse into enterocytes from micelles
• Reassembled into triglycerides
• Packaged into chylomicrons for lymphatic transport
Can you identify at least three different types of surgery to help with weight loss by impacting on digestion and absorption and can you explain the surgical process and how the intervention leads to weight loss (i.e. liposuction doesn’t count)?
Gastric Bypass (Roux-en-Y)
• The surgeon creates a small pouch at the top of the stomach and connects it directly to the small intestine, bypassing most of the stomach and part of the intestine.
• This limits how much you can eat and reduces calorie absorption.
• It is a major procedure, usually for those with a BMI over 35–40 and weight-related health conditions.
Sleeve Gastrectomy (Gastric Sleeve)
• About 80% of the stomach is removed, leaving a narrow, tube-shaped “sleeve.”
• The smaller stomach restricts food intake and makes you feel full sooner.
• It is irreversible and now the most popular bariatric surgery in the UK and US.
Gastric Banding (Adjustable Gastric Band)
• An inflatable silicone band is placed around the upper part of the stomach, creating a small pouch above the band.
• The band can be adjusted to control the size of the opening, limiting food intake.
• It is less invasive and reversible, but generally results in slower weight loss compared to other procedures.
