P3.1. Amino Acids Flashcards
Amino Acid is an organic compound that contains both an ____ and ____ attached to the ____ carbon atom.
- AMINO GROUP
- CARBOXYL GROUP
- SAME
The position of carbon atom is ____.
Alpha (a)
-COOH and -NH2 groups were attached at the ____.
alpha (a) carbon atom
-R group or the side chain varies in?
there are 7 s s c a f h c
- size
- shape
- charge
- acidity
- functional groups present
- hydrogen-binding ability
- chemical reactivity
there are ____ amino acids known.
> 700
the 20 standard amino acids have common ____.
R groups/ side chains
they are the ones who distinguishes what type of amino acid is present.
@ a pH of 7.4:
1. -COOH ____ Hydrogen Ions
2. -NH2 ____ Hydrogen Ions
- looses
- receives
- they are HYDROPHOBIC [water-fearing] Amino Acids.
- SUBTYPES: Alkyl, Aromatic
Non-Polar Amino Acids
3 AROMATIC Non-polar Amino Acids:
- Phenylalanine
- Tryptophan
- Tyrosine
there are ____ out of 20 Non-Polar Amino Acids.
8
- they are HYDROPHILIC [water-loving] Amino Acids.
- SUBTYPES: Neutral, Acidic, Basic
Polar Amino Acids
There is no ____ inside proteins.
polarity
R groups are ____.
Polar
Three types of Amino Acids:
- Polar-neutral
- Polar acidic
- Polar basic
- contains polar but neutral side chains
- 6 amino acids belong in this category
- they can interact w/ water
- capable of forming hydrogen bonds
they contain HYDROXY AMINE ACIDS due to the alcohol group express in their chains.
Polar-Neutral
- Serine
- Threonine
- contain carboxyl group as part of the side chains.
- 2 amino acids belong to this category
Polar Acidic
- Contain amino group as part of the side chain
- 3 amino acids belong to this category
- ionic amino acids
Polar Basic
4 Classification of Amino Acids:
- R group/ Side chain & ring structure present
- Reaction in solution or charge
- Number of amino or carboxyl groups present
- Nutritional Importance
7 components under R group/ Side chain & ring structure present:
- Aliphatic side chain
- Hydroxyl groups
- Sulfur atoms
- Acidic groups or their amides
- Basic groups
- Aromatic rings
- Imino acids
w/ ALIPHATIC SIDE CHAINS:
GLYCINE
ALANINE
VALINE
LEUCINE
ISOLEUCINE
w/ HYRDROXYL GROUPS
Serine
Threonine
w/ SULFUR ATOMS
Cysteine
Cystine
Methionine
w/ ACIDIC GROUPS/AMIDES
Asparagine
Glutamine
Aspartic Acid
Glutamic Acid
w/ BASIC GROUPS
Histidine
Lysine
Hydroxy Lysine
Arginine
w/ AROMATIC RINGS
Phenyalanine
Tryptophan
Tyrosine
w/ IMINO ACIDS
Proline
Hydroxy Proline
the reaction in solution or charge:
a. acidic: aspartic acid & glutamic acid
b. basic: arginine, lysine & histidine
c. neutral
the number of amino and carboxyl groups present:
Mono-amino mono-carboxylic acid (Glycine)
Mono-amino dicarboxylic acid (Glutamate)
Nutritional Importance of Amino Acids:
Essential Amino Acids
Non-essential Amino Acids
- amino acids that are not synthesized in our bodies.
its examples:
Essential Amino Acids
methionine
arginine
tryptophan
- amino acids that are synthesized in our bodies.
Non-essential Amino Acids
Properties of Amino Acids:
- Optical Isomerism
- Acid-base or Charge Properties of Amino Acids
- Standard Amino Acid that is not optically active
- its R group is Hydrogen
Glycine
Chiral centers exhibit ____.
enantiomerism (left- and right-handed forms)
TRUE or FALSE
Each of the 19 amino acids exist in left and right handed forms.
TRUE
- preferred form when it comes to AMINO ACIDS
- preferred from when it comes to CARBOHYDRATES
- L-isomers/ type
- D-isomers/ type
rules for drawing Fischer projection formulas for amino acid structures:
1) -COOH = TOP
2) -R group = BOTTOM
3) -NH2 = LEFT [L-somer] or RIGHT [D-isomer]
Three different species in an AMINO ACID solution:
ZWITTERION
Positive Ion
Negative Ion
Equilibrium shifts when there is a change in ____.
pH
- pH at which the net charge is zero
- net charge is zero
Isoelectric point (pI)
Different amino acids have ____ isoelectric points.
different
At isoelectric point - amino acids are ____ towards an applied electric field because their ____.
- not attracted
- net charge is zero
Cysteine is the only amino acid with a ____ group.
SULFHYDRYL GROUP (-SH group)
imparts cysteine a chemical property unique among the standard amino acids.
sulfhydryl group
this amino acid when in the presence of mild oxidizing agents dimerizes to form a cystine molecule
DIMERIZES: combine with a similar molecule to form a dimer.
Cysteine
Cystine - two cysteine residues linked via a ____.
covalent disulfide bond
3 TYPES PEPTIDES:
Dipeptide: bond between two amino acids
Oligopeptide: bond between 10 - 20 amino acids
Polypeptide: bond between large number of amino acids
Every peptide has an ____-terminal end and a ____-terminal end
- N
- C
contain the same amino acids but present in different order are different molecules (constitutional isomers) with different properties
ISOMERIC PEPTIDES
length of the peptide chains increases…
number of isomeric peptides increases [rapidly]…
small peptides that are biochemically active
Hormones
Neurotransmitters
Antioxidants
Best-known peptide hormones
OXYTOCIN
VASOPRESSIN
Oxytocin and Vasopressin:
1. are produce in?
2. stored in?
- hypothalamus
- posterior pituitary gland
Hormones are:
____ with six of the residues held in the form of a loop by a ____ formed between two cysteine residues
- nonapeptide (nine amino acid residues)
- disulfide bond
- are pentapeptide neurotransmitters produced by the brain and bind receptor within the brain
- reduces pain.
Enkephalins
Best-known enkephalins:
Met-enkephalin
Leu-enkephalin
Met-enkephalin: Tyr–Gly–Gly–Phe–Met
Leu-enkephalin: Tyr–Gly–Gly–Phe–Leu
