Biological Chemistry - Week 22-23 Flashcards
What type of molecule are sugars?
Organic molecules with a lot of hydroxyl (OH) groups.
Also called (mono/poly) saccharides or carbohydrates.
What is the relationship between the linear and cyclic form of glucose?
Groups on left are up in cyclic form
Groups on right are down in cyclic form
What is an enantiomer?
When everything has flipped sides.
What would C-3 epimer mean?
The 3rd carbon (carbon 3) has flipped sides.
What is a glycoside linkage?
bond formed between two monosaccharides.
Forms a stable acetal between two sugar molecules
What type of reaction forms a glycoside linkage?
a condensation reaction because it produces a molecule of water
Where are glycoside linkages found?
Found in cellulose, chitin and lactose.
Used for branches in glycogen and other polysaccharides.
Found in main backbone of a polysaccharide
What is the difference in a reducing vs a non-reducing sugar?
Reducing sugars can revert back to linear form and be oxidised.
What conditions are needed to reduce a carbonyl to an alcohol?
D-Glucose —-> D-glucitol
formation of sugar alcohols (alditols)
=NaBH4
What are the 2 types of nucleic acids?
Deoxyribonucleic acid (DNA)
Ribonucleic acid (RNA)
What are the 2 categories of nucleic bases?
Purines and Pyrimidines
What are the purine bases?
Adenine and Guanine
What are the pyrimidine bases?
Thymine, Cytosine, Uracil
What bases pair and how many bonds from between them?
A and T/U —-> 2 bonds
G and C —> 3 bonds
What is the complementary DNA and RNA strand for: 5’-AGC CGA AGC AGA CTT-3’
Complementary DNA:
5’-TCG GCT TCG TCT GAA-3’
Complementary RNA:
5’-UCG GCU UCG UCU GUU-3’
What position are nucleic bases attached to nucleosides?
On the 2 position of the sugar
Where are phosphates attached on nucleotides?
One or more phosphates are attached at the 5’ position of the sugar.
What are the 3 types of RNA?
messenger RNA (mRNA)
ribosomal RNA (rRNA)
transfer RNA (tRNA)
What is the difference between mRNA and tRNA?
for generic RNA give the mRNA sequence, tRNA will be different
tRNA is the complementary sequence of mRNA.
What are amino acids the building blocks of?
building blocks of peptides and proteins
What determines the type of amino acid present?
Amino acids contain a minimum of two groups with acid-base character.
Their net charge determines pH.
What are the three different forms of amino acids possible?
Acidic, basic or neutral amino acids.
What is the isoelectric point (pl)
the pH at which an amino acid is in its zwitterionic form
5.5 - 6.0 for neutral amino acids
What is the formula for isoelectric point?
pl = (pKa1 + pKa2) / 2
