Introduction Flashcards
What is entropy?
disorder
Is free energy change positive or negative in exergonic reactions?
negative
In endergonic reactions, is total free energy of products more or less than in reactants?
more
Which type of reactions, exergonic or endergonic, can occur spontaneously?
exergonic
What happens to free energy released as you move closer to equilibrium?
increases
In readily reversible reactions (those close to equilibrium) what is the free energy change value?
close to zero
Which free energy change values are good in reactions which are control points?
large negative values
What type of free energy change value does conversion of ATP to ADP have?
large negative
Does the forward reaction of Glucose-6-phosphate into glucose-1-phosphate have a positive or negative value for free energy change?
positive
Is water polar or non polar?
polar
What are water molecules like?
bent, form a dipole, tetrahedral shape
What charge does hydrogen have?
partial positive charge
What shape are hydrogen bonds?
linear
In micelle formation what do the balls represent?
hydrophilic heads
In micelle formation what do the zag zag lines represent?
hydrophobic tails
What are the bonds between amino acids?
peptide
From which terminal to which does the direction go in the peptide chain?
N terminal to C terminal
What is the character and shape of peptide bonds?
partial double bond character
Peptide bonds are planar
Peptide bonds are strong and rigid
-important for folding of proteins
Are acids proton donors or acceptors?
donors
What is pH?
Measurement of the amount of protons in a solution
What do amino acids without charged side groups exist as in neutral solution?
zwitterions with no net charge
How many titratable groups do zwitterions have?
2
What is the isoelectric pH?
The pH at which a molecule has no net charge
Can the ends of proteins be ionised?
Yes
Can proteins act as buffers?
Yes e.g. haemoglobin
What is primary structure?
the sequence of amino acid residues
What is secondary structure?
localised conformation of the polypeptide backbone
What is tertiary structure?
the three-dimensional structure of an entire polypeptide, including all its side chains
What is quaternary structure?
spatial arrangement of polypeptide chains in a protein with multiple subunits
What break alpha helixes?
proline residues
What component of bone and connective tissue is the most abundant protein in vertebrates?
collagen triple helix
What can lack of collagen cause?
bleeding gums, scurvy etc
Which are soluble in water, fibrous or globular proteins?
globular
What are examples of fibrous proteins?
keratin, collagen
Where do amino acids with hydrophobic side-chains tend to cluster?
centre of globular proteins
What change occurs in sickle cell anaemia?
Single nucleotide sequence change
in coding region of the b chain of haemoglobin A
Results in altered protein
-valine in stead of glutamic acid
Which proteins sometimes aid the folding process?
chaperones
What is prion disease an example of?
folding polypeptide disease
What does haemoglobin consist of?
four subunits
two alpha and two beta chains
each contains a haem group
