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CHEM 100 Hybrid - Lecture 11 - FULL

Justin Gatewood・2 minutes read

Unit 11 focuses on lipids and proteins, discussing their structures, functions, and roles in the body. Lipids, like fats and oils, have unique characteristics, while proteins have primary, secondary, tertiary, and quaternary structures essential for their functions, such as catalysis, movement, and defense in the body.

Insights

Lipids are a diverse group of substances from living organisms that do not dissolve well in water, encompassing fats, oils, phospholipids, and steroids with variations based on fatty acid composition.
Fatty acids, essential for various bodily functions, can be saturated or unsaturated, with unsaturated fats causing kinks and liquids at room temperature, while saturated fats are solids.
Proteins, essential for catalysis, structure, defense, and more, have primary, secondary, tertiary, and quaternary structures, with disruptions in these structures impacting protein function, as seen in diseases like sickle cell anemia.

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Recent questions

What are lipids composed of?
Lipids are diverse substances from living organisms.
How are fatty acids represented?
Fatty acids can be represented numerically based on structure.
What is the role of essential fatty acids?
Essential fatty acids must be obtained from the diet.
What are triacylglycerols?
Triacylglycerols store energy efficiently in the body.
How are proteins structured?
Proteins have primary, secondary, tertiary, and quaternary structures.

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Summary

00:00

Unit 11: Lipids, Proteins, and Carbohydrates Summary

Lipids and proteins are the focus of Unit 11, following the previous discussion on carbohydrates.
Carbohydrates have specific structural features and bonding patterns, unlike lipids which are defined by their function and solubility in nonpolar solvents.
Lipids encompass a diverse group of substances from living organisms that do not dissolve well in water.
The lipid class includes fats, oils, phospholipids, and steroids, with variations based on the composition of fatty acids esterified to glycerol.
Fatty acids are characterized by long hydrocarbon chains with carboxylic acid functional groups, with the number of carbons in the chain typically being even.
Saturated fatty acids lack carbon-carbon double bonds, while unsaturated fatty acids have double bonds that determine their saturation level.
Fatty acids can be represented by a numerical system indicating the total number of carbons in the chain and the number of double bonds.
Unsaturated fatty acids predominantly exist in the cis form due to steric hindrance, with trans forms being less favored in nature.
Saturated fatty acids have straight chains, while unsaturated fatty acids with double bonds exhibit kinks in their structure.
Essential fatty acids must be obtained from the diet as they cannot be synthesized by the body, while nonessential fatty acids can be produced internally.

16:54

"Triacylglycerols: Fatty Acid Energy Storage and Structure"

The portion to the right of oxygen is known as an acyl group, referred to as triacylglycerols or triglycerides.
Triacylglycerols are formed by esterifying OH groups on a glycerol molecule with fatty acid chains.
Mono and diacylglycerols exist but are in low concentrations compared to triacylglycerols.
Fatty acid chains in triacylglycerols can be saturated or unsaturated, with unsaturated ones causing kinks and resulting in liquids at room temperature.
Saturated fatty acids in triacylglycerols can pack tightly together, making them solids at room temperature.
Trans fats are structurally similar to unsaturated fats but are as harmful as saturated fats.
Triacylglycerols are hydrophobic and are stored in adipose tissue as long-term energy reserves.
Triacylglycerols store more energy efficiently than glycogen, with 9.3 kilocalories per gram compared to 4.1.
Fats provide insulation and are good for waterproofing, as seen in ducks' feathers.
Triacylglycerols can be broken down into glycerol and fatty acids through hydrolysis, saponification, and hydrogenation reactions.

33:23

"Essential Biochemical Molecules in Brief"

Waxes are esters with long carbon chains on both sides, used in products like lip balms.
Waxes consist of esters with long carbon chains on both sides, such as long chain alcohols and fatty acids.
Phospholipids or phosphoglycerides contain glycerol with fatty acids esterified to two OH groups and a phosphate group.
Phospholipids also have an alcohol attached to the phosphate group, often an amino alcohol.
Steroids, like cholesterol, have a characteristic four-fused ring system and play essential roles in the body.
Cholesterol is crucial for hormone production, vitamin D synthesis, and membrane structure.
Hormones like progesterone, testosterone, and estradiol are derived from cholesterol precursors.
Amino acids are the monomeric units of proteins, with 20 standard amino acids commonly found in proteins.
Amino acids have a basic structure with an alpha carbon differentiating their side chains.
Amino acids can be represented by one or three-letter designations based on the characteristics of their side chains.

51:48

Amino Acids and Protein Structure Basics

Amino acids can be classified based on their groups, such as polar, acidic, or basic.
Most amino acids have four different groups attached to the alpha carbon, making them chiral.
Amino acids, except for glycine, have stereo isomers called enantiomers.
Proteins are formed through dehydration reactions, such as peptide bond formation.
Peptide bonds, also known as amide linkages, link adjacent amino acids in proteins.
Once amino acids are linked, they are referred to as residues.
Proteins have various functions, including catalysis, structure, movement, defense, regulation, and transport.
The hierarchy of protein structure includes primary, secondary, tertiary, and quaternary structures.
Primary structure refers to the sequence of amino acids in a protein.
Secondary structures like alpha helices and beta-pleated sheets are stabilized by hydrogen bonding along the main chain.

01:09:33

Protein Structures: Beta Sheets to Quaternary Interactions

Beta-pleated sheets are like pleats, with two types: parallel and antiparallel, determined by the peptide's direction.
Peptide direction is discerned by the amino and carboxyl terminals, with N, C alpha, and C carbonyl indicating the peptide's path.
Antiparallel strands run in opposite directions, while parallel strands run in the same direction, represented by arrows.
Beta sheets can be multiple layers thick, with hydrogen bonding between carbonyl oxygens and amino hydrogens.
Antiparallel strands are stronger due to straighter hydrogen bonds, while parallel strands are weaker.
Tertiary structures are functional proteins with unique configurations, influenced by R-group interactions.
Tertiary structures are governed by hydrophobic, electrostatic, hydrogen bonding, and covalent interactions.
Primary, secondary, and tertiary structures are crucial in protein formation, with quaternary structures being interactions of tertiary structures.
Quaternary structures, like hemoglobin, are stabilized by the same forces as tertiary structures.
Disruption of these forces can impact a protein's function, as seen in examples like sickle cell anemia caused by a single mutation.

01:27:24

Proteins: Structure, Denaturation, and Digestion

Proteins have a primary structure with three-letter designations, secondary structures like alpha helices and beta sheets, and tertiary structures with interacting beta sheets and alpha helices. Hydrolyzing proteins involves splitting water and breaking down proteins into amino acids through protein digestion.
Denaturing proteins results in a permanent loss of activity, such as when cooking an egg denatures the egg albumin irreversibly. Denaturing can be caused by disrupting forces like hydrophobic, electrostatic, covalent, or hydrogen bonding, influenced by factors like organic solvents, pH, heavy metal ions, and temperature changes that can lead to protein destabilization and potential harm to the body.

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