The Patient Semester 1 Flashcards
Which amino acid has the following side chain?
Glycine
Which amino acid has the following side chain?
Methionine
Which amino acid has the following side chain? -CH2-CH2-CH2- Forming a cyclic peptide
Proline
Which amino acid has the following side chain?
Alanine
Which amino acid has the following side chain?
Valine
Which amino acid has the following side chain?
Isoleucine
Which amino acid has the following side chain?
Lysine
Which amino acid has the following side chain?
Arginine
Which amino acid has the following side chain?
Histidine
Which amino acid has the following side chain?
Aspartate/Aspartic Acid
Which amino acid has the following side chain?
Glutamate/Glutamic Acid
Which amino acid has the following side chain?
Tyrosine
Which amino acid has the following side chain?
Phenyl Alanine
Which amino acid has the following side chain?
Threonine
Which amino acid has the following side chain?
Serine
Which amino acid has the following side chain?
Cysteine
Which amino acid has the following side chain?
Aspargine
Which amino acid has the following side chain?
Glutamine
Which amino acid has the following side chain?
Tryptophan
Which amino acid has the following side chain?
Leucine
Which amino acid has two chiral centres?
Isoleucine
How many amino acids are in a chain before it is considered a protein?
50 or more
Approximately how many different proteins does one cell contain?
>10,000
What percentage of dry cell weight do proteins account for?
>50%
Which of the -L or -R isomers exist naturally in amino acids?
Only the -L form
Spelling out CORN in a clockwise direction when the hydrogen is drawn as a forward wedge.
What rotation an occur aroud the alpha-carbon atom and what are the torsion angles known as?
Free rotation is possible around the alpha-carbon.
C-N by the phi angle
C-O by the psi angle
Favoured rotations leave the R groups in trans configuration
What kind of reaction joins two alpha-amino acids together?
Condensation- removal of water
In which part of the cell do amino acids join together to form a peptide?
The ribosomes
In what direction is a polypeptide sequence written?
From the N-terminus to the C-terminus
How long should a single C-N bond measure?
1.49 angstrom
How long should a double C=N bond measure?
1.27 angstrom
What is the actual length of a C-N bond within a peptide? And why?
The actual length is 1.32 angstrom.
This is because C-N behaves partially like a double bond due to resonance stabilisation.
Why is the peptide bond planar?
Due to restricted rotation around the C=O bond.
Which two amino acids have non-polar side chains?
Methionine
Proline
Which three amino acids have basic side chains?
Lysine
Arginine
Histidine
Which two amino acids have acidic side chains?
Aspartate
Glutamate
Which three amino acids have aromatic side chains?
Tyrosine
Phenylalanine
Tryptophan
Which five amino acids have hydrophillic side chains but are neutral?
Serine
Threonine
Asparagine
Glutamine
Cysteine
Which amino acid can form S-S bonds? And where can they form?
Cysteine can form S-S bonds interchain and intrachain, altering the overall protein shape.
What are the two most common secondary structures of amino acids?
Alpha-helixes
Beta-strands
Approximately how long is a hydrogen bond within a protein structure?
~2.2-3.5 angstrom
What torsion angles give an alpha-helix?
phi- 57
psi- 47
How many residues are there per turn in an alpha-helix?
3.6
Which -NH does the -CO of an amino acid form a hydrogen bond with?
The -NH of the 4th residue ahead
What are the four main features of an alpha-helix?
R groups extend on the outside
It twists clockwise
Peptide bonds are planar
Peptide bonds are trans
How are polypeptide coils formed?
Alpha-helices wind around eachother, they are extremely stable
How many amino acids must be present to form a Beta sheet?
At least 5
What are the three main observations in parallel Beta-sheets?
R groups point up and down
Strands are held together by Hydrogen bonding between strands
Both strands run from the N-terminus direction
What makes antiparallel B-sheets different to parallel ones?
In antiparallel sheets, the strands run in opposite directions
How many types of Beta turns are there? And what are they used for within a peptide?
There are two types and they are used to change direction
What are the two types of turn within a polypeptide and what are their characteristics?
Loops- contain hydrophillic residues in stretches
Used to connect alpha-helices and beta-sheets
No regular structure
Found on the surface of proteins
Turns- less than five residues
Better defined than loops
What are the three levels of structrure complexity?
Motifs- arrangement of two of more secondary structural elements
Domain- many folded motifs giving stable, self contained structure
Subunit- combining many domains
What are the features of a disulphide bond?
Covalent and occur via oxidation
2.2 angstroms in length
167kJ/mol in strength
What is the strength of a hydrogen bond inside protein?
2-7kcal/mol in strength
What is the formula for Gibbs Free Energy? What does it measure?
A negative delta G means that it is stable.
What is the strength of the van der Waals forces in each C-H within a hydrocarbon?
8.4kJ/mol
What is the average strength of a hydrophobic bond within a protein?
4kJ/mol
What is the main driving force for protein binding/folding in aqueous solution?
The increased entropy of water as hydrophobic groups bury inside
What is glycolysis?
Anaerobic degradatin of glucose to produce ATP and pyruvate, occurs in the cytosol
What is the size of a prokaryotic cell?
1-5 micrometers in diameter
What is the size of a eukaryotic cell?
10-100 micrometers in diameter
How do ribosomes vary from prokaryotes to eukaryotes?
In eukaryotes they are 80S in size
In prokaryotes they are 70S in size
In eukaryotic organelles they are 70S
What is the thickeness of a membrane?
6-10nm
What is the basic structure of a phosphoglyceride?
What are phosphogylcerides derived from?
Glycerol or sphingosine
Define monounsaturated.
Contain only one double bond
How are fatty acids stored?
As triglycerides
What are glycolipids?
Sugar containing lipids with a sphingosine backbone
What 2 things alter the melting point of a fatty acid chain?
The number of carbons in the chain increases the melting point
The number of double bonds reduces the melting point
What are eicosanoids?
Chemical mediators (such as prostaglandins and thromboxanes) within the body derived from omega-3 and omega-6 fatty acids
