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BCM210-BioChemistry > Top2-Ch2-P46-54Reverse > Flashcards

Flashcards in Top2-Ch2-P46-54Reverse Deck (22)
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22
Q

CO2, O2, N2

A

What are three biologically important gases that are non-polar and therefore not soluble in water.

23
Q

mixed polar and non polar character

A

Amphipathic molecules have

24
Q

poor

dissolve

chloroform and benzene,

A

Non-polar solvents are poor/good solvents for polar molecules, but easily dissolve/don’t dissolve non-polar molecules.

Name two non-polar solvents

25
Q

hydration (A process in which water molecules are attracted to and form weak bonds with the soluble species.)

This occurs when hydrophilic compounds dissolve in water.
Formation of hydration spheres stabilise ions or dipoles

A

Water as ionic solvent.

The attractive/ repulsive forces between charged compounds is partially neutralised by _____

26
Q
  1. H-bonds
  2. Ionic interactions
  3. Hydrophobic interactions
  4. Van der Waals interactions
A

Name the four types of noncovalent (weak) interactions among biomolecules in aqueous solvent.

27
Q

weaker

A

Are noncovalent interactions weaker or stronger than covalent bonds?

28
Q
  1. 3D shape of proteins are influenced by these interactions
  2. Binding of hormone to cellular receptor protein is the result of multiple weak interactions
A

Noncovalent (‘Weak’) interactions are continually forming and breaking, as strength of solute-solvent (water) is nearly as favorable as solute-solute.

The cumulative effect can be very significant. Give two examples.

29
Q

Forces that hold nonpolar regions together

Minimising ordered water molecules surrounding compound (water cage) to achieve greater thermostability (higher entropy)
Consider the behaviour of amphipathic molecules in water

See diagram below where: The hydrophobic portions of amphipathic molecules (a fatty acid here) interrupt the H-bonded molecular structure of water.

The decreased entropy (stable ordering of water at the margin) is energetically unfavourable

A

Hydrophobic interactions are?

Explain a bit.

30
Q
A

Watercages picture.

31
Q

group together in water

A

In order to achieve greater thermodynamic stability, and minimise the amount of hydrophobic area exposed to the polar solvent non-polar, hydrophobic regions of amphipathic compounds (e.g. fatty acids or membrane lipids) tend to

32
Q

micelles

micelles

Micelles are shaped with the non-polar regions tending to group together leaving the polar regions on the outside

A

Clusters of lipids condense into _____?
These, _____ are energetically more favourable because no ordered “water cages”. Explain how these clusters are shaped.

33
Q

a state in which a chemical system is neither consuming or releasing heat energy.

A

Thermodynamic stability is

34
Q
  1. hydration
  2. “fit”, example is e.g. binding substrates to enzymes displaces water
A
  1. In H-bonding between polar molecules the binding of polar molecules reduces _____.
  2. Non covalent interactions must provide a good _____ . give an example of this bonding.
35
Q
  1. Very simply, the attraction of opposite charges for each other.
  2. the cube of the radius (volume), so that distance is important in bond strength (must be a good ‘fit’)
A
  1. Ionic/electrostatic interactions are?
  2. The attraction decreases with
36
Q

London forces

Description:

  • Weak transient dipole attractions
  • surrounding electron clouds influence each other
  • Counter-balanced by repulsive forces of 2 electron clouds, to give final van der Waals radius
  • These are extremely close proximity between atoms.
  • i.e. require exact fit of surfaces
A

Van der Waals interactions are also called ?

Describe these forces?

37
Q

Yes

A

Do all the noncovalent bonds in water involve electrical charges. yes or no?

38
Q

Van der Waals interactions

A

Which are the weakest of all non-covalent forces?

39
Q

H2O

H3O+ and OH

ionisation

A

Not all water molecules are in the form ___. A small degree of ionisation occurs in water so there are some ___ and ___ as well. This is called the _____ of water.

40
Q
  1. About 1 in one ten million
  2. equilibrium
A
  1. What numbers of water molecules are ionised?
  2. These ions are in _____ with the water molecules
41
Q

Hydronium ions H3O+

A

H+ free protons do not exist in solution even though we usually show it. Instead what type of ions exist?

42
Q

electrical conductivity.

A

Ionisation of water is measured by its?

43
Q

H3O+, OH-

A

Pure water carries electrical current as ____ migrates toward the cathode and _____ toward the anode.