Biochemistry: Amino Acids, Proteins, Water and PH - Lecture 3 Flashcards

1
Q

If something dissolves in water what is it said to be?

A

Hydrophilic

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2
Q

Why is water a dipolar molecule?

A

Due to electronegative oxygen and unequal sharing of electrons

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3
Q

What does Dipolar mean?

A

Dipolar means that it is more charged on one side than the other

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4
Q

What shape does water have?

A

Has a tetrahedral shape.

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5
Q

What are the interactions of water?

A

Ion to dipole interactions

Dipole to dipole interactions

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6
Q

What shape are H-bonds?

A

These bonds tend to be linear

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7
Q

How do Non-polar substance react in water?

A

Non polar substance are insoluble in water - hydrophobic

Powerful attraction between water molecules - water molecules push non-polar molecules
together.

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8
Q

What effect is shown when water reacts with oil?

A

Hydrophobic effect

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9
Q

What are Amphipathic Molecules?

A

Have domains that are either hydrophobic/hydrophilic

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10
Q

What are Micelles?

A

lipids that have a hydrophilic head and a hydrophobic tail form in water - Heads on the Outside, tails in the inside

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11
Q

What is the general structure of an amino acid?

A

Amino Group - C(H)R - Caroxylic acid group

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12
Q

What type of carbon is at the centre of an amino acid?

A

An Alpha carbon

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13
Q

What will Hydrophobic amino acids react with?

A

They will react with lipid and other non polar substances. Common in
membrane spanning parts of the protein.

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14
Q

What will Polar uncharged Amino Acids react with?

A

These amino acids are able to hydrogen bond with water therefore are partially soluble

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15
Q

What are Acid/Basic Amino acids used?

A

Useful as a buffer

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16
Q

How is peptide bond formation catalysed?

A

Catalysed by peptidyl transferase

17
Q

What shape are Peptide bonds?

A

Planar

18
Q

What types of molecules are acids?

A

Acids are molecules that donate a proton

19
Q

What types of molecules are bases?

A

Bases are proton acceptors

20
Q

What is the equation for Ka?

A

Ka=[H+][A−]/[HA]

21
Q

What is the equations for pH?

A

pH=−log[H+]

pH= pKa + log[A-]/[HA]

22
Q

What does Ka measure?

A

The numerical value of Ka is used to predict the extent of acid dissociation. A large Ka values indicates stronger acids (more of the acid dissociates) and small Ka values indicates weaker acids (the reaction does not go to completion).

23
Q

What is a buffer?

A

A buffer is a solution to control the pH of a reaction mixture -amino acids are work as a buffer

24
Q

Why do amino acids have two pKa values?

A

Two Titratable groups
Amino group postivie
Carboxyl group negative

25
Q

What is a Zwitterion?

A

A Neutral amino acid, with a positive and negative charge