From: Andrew Lorimer <andrew@lorimer.id.au>
Date: Mon, 9 Sep 2019 09:51:21 +0000 (+1000)
Subject: [chem] proteins
X-Git-Tag: yr12~37
X-Git-Url: https://git.lorimer.id.au/notes.git/diff_plain/3e6f607c1f4a8c60052585e65c2f8399313ae4a7

[chem] proteins
---

diff --git a/chem/food.pdf b/chem/food.pdf
index abbf0f1..dbbe738 100644
Binary files a/chem/food.pdf and b/chem/food.pdf differ
diff --git a/chem/food.tex b/chem/food.tex
index f3c17fe..26d12f1 100644
--- a/chem/food.tex
+++ b/chem/food.tex
@@ -22,7 +22,118 @@
   \date{}
   \maketitle
 
-  \subsection*{Carbohydrates}
+  \section{Vitamins}
+
+  \subsection*{Fat-soluble vitamins}
+
+  \begin{itemize}
+    \item Carbon and hydrogen
+    \item Non-polar (few or no polar groups)
+    \item Soluble in other non-polar solvents e.g. fats, oils
+    \item Can be synthesised endogenously
+  \end{itemize}
+
+  \subsection*{Water-soluble vitamins}
+  
+  \begin{itemize}
+    \item Absorbed directly into bloodstream
+    \item Catalyse cellular reactions
+    \item Excreted through kidneys in urine
+    \item Must be obtained from food
+  \end{itemize}
+
+  \section{Proteins}
+
+  \begin{itemize}
+    \item All proteins contain C, H, O, N
+    \item Plants make proteins from inorganic compounds, animals cannot
+    \item Built from monomers called \textbf{amino acids}
+  \end{itemize}
+
+  \subsection*{Aminio acids}
+
+  \begin{itemize}
+    \item Contains amino (\ce{-NH2}) and carboxyl (\ce{-COOH})
+    \item Most have four groups bonded to central atom
+    \item May be polar or non-polar (amphoteric), acidic or basic
+    \item \textbf{Essential amino acids} - cannot be synthesised, must be supplied in diet
+    \item Amino acids (except glycine) are enantiomers due to chiral centres
+    \item Must be correct chirality to act as a biological catalyst
+  \end{itemize}
+
+  % amino acid general structure (see Jacaranda p.328)
+
+  \chemfig{\color{red}N(-[:135]H)(-[:225]H)-[:-45]C(-[:-90]\color{yellow}\textit{R})(-H)-[:45]\color{blue}C(=[:90]O)-OH}
+
+  \subsection*{Zwitterions}
+
+  \begin{itemize}
+    \item Zwitterion = \textit{dipolar ion}
+    \item Behaves as a base in acidic environments: \ce{-COOH- + H+ -> -COOH}
+    \item Behaves as an acid in basic environments: ammonium group loses \ce{H+} \(\implies\) anionic form
+  \end{itemize}
+
+  % Zwitterion structural equation (Jacaranda p.330)
+
+  \[ \ce{$\underset{\text{acid form}}{\ce{^+H3N-CH2-COOH}}$ <=>[+H+] $\underset{\text{zwitterion form}}{\ce{^+H3N-CH2-COO-}}$ <=>[-H+] $\underset{\text{basic form}}{\ce{H2N-CH2-COO-}}$} \]
+  \[ \text{cationic} \hspace{12cm} \text{anionic} \]
+
+  \subsection*{Formation of proteins}
+
+  \[ \text{Amino acid} \rightarrow \text{peptide} \tag{polymerisation} \]
+
+  Peptide group (amide): \ce{-C=ONH} (condensation reaction produces \ce{H2O})
+
+  Amino acid \textit{residue} - product of peptide formation reaction
+
+  Large polypeptides are called \textit{proteins}
+
+  \subsection*{Protein structure}
+
+  \begin{enumerate}
+    \item \textbf{Primary structure} - order of amino acids in peptide chain
+    \item \textbf{Secondary structure} - coils/pleats/folds in polymer
+    \item \textbf{Tertiary structure} - three-dimensional structure, e.g. H-bonding, ionic bonding
+    \item \textbf{Quaternary structure} - arrangement of multiple protein molecules
+  \end{enumerate}
+
+  % diagram of structural levels (Jacaranda p.332)
+
+  \subsection*{Enzymes}
+
+  \begin{itemize}
+    \item Biological catalysts (lowers \(E_A\))
+    \item Names usually end in \textit{-ase}
+    \item Every enzyme has a unique 3D shape
+    \item Rate of reaction \(\propto\) concentration up to \textit{saturation point}
+    \item \textbf{Substrate} - reactant molecule
+    \item \textbf{Active site} - destination of substrate
+  \end{itemize}
+
+  % enzyme catalyst diagram (Jacaranda p.334)
+
+  \subsubsection*{Lock and key model}
+
+  Reactants and enzymes must have complementary shapes
+
+  \subsubsection*{Indicued fit model}
+
+  Active site may change to fit subtrate
+
+  \subsection*{Coenzymes}
+
+  "Helper" molecules to enzymes. Non-protein molecules. Temporarily forms a loose bond with protein molecule to form active enzyme. Coenzymes are not specific to the substrate (different to enzymes).
+
+  \section*{Digestion of protein}
+
+  Proteins are hydrolysed by the \textit{pepsin} enzyme (\(\implies\) addition of \ce{H2O}).
+
+  \begin{description}
+    \item [Hydrolysis:] breaking of strong covalent (peptide) bonds
+    \item [Denaturation:] breaking of weak bonds (dispersion, H-bonds)
+  \end{description}
+
+  \section{Carbohydrates}
 
   \subsubsection*{Monosaccharides}