Video Notes Flashcards: Organic Molecules, Membrane Transport & Digestion

Vocabulary flashcards covering organic molecules, membrane transport, and digestion as described in the notes.

Carbohydrates

Organic compounds of C, H, O in a 1:2:1 ratio; functions include quick energy, storage (glycogen, starch), and structure (cellulose, chitin).

Monosaccharides

Simple sugars that are the building blocks of carbohydrates (e.g., glucose, fructose, galactose).

Glucose

A common monosaccharide; primary energy source for cells.

Fructose

A monosaccharide found in fruit; part of the disaccharide sucrose.

Galactose

A monosaccharide component of lactose.

Disaccharides

Carbohydrates formed by two monosaccharides (e.g., sucrose, lactose).

Sucrose

Disaccharide composed of glucose + fructose.

Lactose

Disaccharide composed of glucose + galactose.

Polysaccharides

Long polymers of monosaccharides; include starch, glycogen, cellulose, chitin.

Starch

Plant storage polysaccharide.

Glycogen

Animal storage polysaccharide stored in liver and muscles.

Cellulose

Plant structural polysaccharide that strengthens cell walls.

Chitin

Polysaccharide in insect exoskeletons and fungal cell walls.

Glycogen storage disease

Impaired glycogen breakdown causing blood sugar drops between meals and fatigue.

Lipids

Hydrophobic, nonpolar molecules rich in carbon and hydrogen; fewer oxygens than carbohydrates.

Triglycerides

Glycerol bound to three fatty acids; main long-term energy storage form.

Saturated fats

Fatty acids with no double bonds; typically solid at room temperature.

Unsaturated fats

Fatty acids with one or more double bonds; typically liquid at room temperature.

Phospholipids

Lipids with a polar phosphate head and two nonpolar fatty acid tails; amphipathic and form cell membranes.

Amphipathic

Molecule with both hydrophilic and hydrophobic parts.

Bilayer

Double layer of phospholipids forming the foundation of cell membranes.

Cholesterol

Sterol lipid; stabilizes membranes and is a precursor to steroids, vitamin D, and bile salts.

Prostaglandins

Fatty acid derivatives that act as local signaling molecules in inflammation, pain, and fever.

Proteins

Macromolecules made of amino acids; perform structural, catalytic, transport, and regulatory roles.

Amino acids

Monomers of proteins; contain amino group, carboxyl group, a central carbon, and an R-group.

Primary structure

Linear sequence of amino acids in a protein.

Secondary structure

Local folding stabilized by hydrogen bonds; includes α-helices and β-sheets.

Alpha-helix

Right-handed helical secondary structure common in proteins.

Beta-pleated sheet

Sheet-like secondary structure formed by hydrogen bonding.

Tertiary structure

Three-dimensional folding of a protein due to R-group interactions.

Quaternary structure

Assembly of multiple polypeptide subunits into a functional protein.

Enzymes

Proteins that act as biological catalysts to accelerate reactions.

Collagen

Structural protein providing strength to connective tissues.

Keratin

Structural protein in hair, nails, and skin.

Actin

Cytoskeletal protein involved in movement and muscle structure.

Myosin

Motor protein that interacts with actin for muscle contraction.

Hemoglobin

Oxygen-carrying protein in blood.

Membrane carriers

Proteins that transport specific substances across membranes via shape changes.

GLUT transporters

Glucose transport proteins; mediate facilitated diffusion of glucose across membranes.

GLUT4

Insulin-dependent glucose transporter in adipose tissue and muscle.

Insulin

Hormone that lowers blood glucose by promoting cellular glucose uptake.

Glucagon

Hormone that raises blood glucose by promoting liver glucose release.

Nucleic Acids

DNA and RNA; store and transmit genetic information.

Nucleotide

Monomer of nucleic acids; sugar + phosphate + nitrogenous base.

DNA

Deoxyribonucleic acid; double-stranded genetic material.

RNA

Ribonucleic acid; usually single-stranded; guides protein synthesis.

ATP

Adenosine triphosphate; cellular energy currency.

Purines

Double-ring bases: Adenine (A) and Guanine (G).

Adenine

Purine base; pairs with Thymine in DNA and Uracil in RNA.

Guanine

Purine base; pairs with Cytosine.

Pyrimidines

Single-ring bases: Cytosine (C), Thymine (T), Uracil (U).

Cytosine

Pyrimidine base; pairs with Guanine.

Thymine

Pyrimidine base in DNA; pairs with Adenine.

Uracil

Pyrimidine base in RNA; replaces Thymine.

Channel proteins

Tubelike openings that diffuse ions or small molecules down their gradient.

Carrier proteins

Proteins that bind specific molecules and move them via conformational change.

Osmosis

Diffusion of water across a semipermeable membrane via aquaporins.

Aquaporins

Water channel proteins that accelerate osmosis.

Hypertonic

Solution with higher solute concentration; causes cell shrinkage.

Hypotonic

Solution with lower solute concentration; causes cell swelling.

Isotonic

Solution with equal solute concentration to inside cells.

Isotonic saline

0.9% NaCl; IV solution that prevents red blood cell lysis.

Mouth

Site of mechanical digestion (mastication) and chemical digestion (salivary amylase, lingual lipase).

Mastication

Chewing that mechanically breaks down food.

Salivary amylase

Enzyme in saliva that begins starch digestion.

Lingual lipase

Lipase active in the stomach that digests lipids.

Esophagus

Tube conveying food via peristalsis; contains skeletal and smooth muscle regions.

Lower esophageal sphincter

Muscular valve preventing reflux into the esophagus.

Stomach

Sac where mechanical digestion and chemical digestion occur; acidic environment.

Pylorus

Distal region of the stomach regulating emptying into the small intestine.

Rugae

Folds in the stomach mucosa allowing expansion.

Parietal cells

Stomach cells that secrete HCl and intrinsic factor.

HCl

Hydrochloric acid; creates acidic gastric environment and activates enzymes.

Intrinsic factor

Gastric protein essential for vitamin B12 absorption.

Chief cells

Stomach cells that secrete pepsinogen.

Pepsinogen

Inactive enzyme activated to pepsin by acidic pH.

Pepsin

Active protease in the stomach that digests proteins.

Mucus cells

Cells that secrete alkaline mucus to protect the stomach lining.

Enteroendocrine cells

Hormone-secreting cells in stomach and intestine.

Small intestine

Primary site of digestion and nutrient absorption; features include circular folds, villi, and microvilli.

Brush border enzymes

Digestive enzymes located on microvilli that finish digestion in the small intestine.

Goblet cells

Mucus-secreting cells in the intestinal lining.

Crypts of Lieberkühn

Glands in the intestine that secrete intestinal juice and house stem cells.

Liver

Organs that produce bile, process nutrients, detoxify, and store vitamins.

Gallbladder

Stores and concentrates bile; releases bile into the small intestine.

Bile salts

Amphipathic molecules that emulsify fats to form micelles for digestion.

Micelles

Aggregates formed during fat digestion to increase surface area for lipase.

Pancreas

Gland that secretes bicarbonate and digestive zymogens into the small intestine.

Bicarbonate

Neutralizes stomach acid in the small intestine.

Zymogens

Inactive enzyme precursors activated in the small intestine.

Trypsinogen

Pancreatic zymogen activated to trypsin in the small intestine.

Chymotrypsinogen

Pancreatic zymogen activated to chymotrypsin in the small intestine.

Procarboxypeptidase

Pancreatic zymogen activated to carboxypeptidase in the small intestine.

Activation in the small intestine

Process by which pancreatic zymogens become active digestive enzymes.

Pancreatic duct blockage

Blockage that prevents enzyme release, leading to severe malnutrition.