Biochemistry Flashcards
What are the building blocks of proteins?
Amino acids
There are roughly 20 amino acids that serve as the building blocks of proteins.
How many amino acids are typically found in human proteins?
Roughly 20
These amino acids are used in human peptides and proteins.
What are some functions of proteins?
Functions of proteins include:
* Transport
* Structure
* Regulatory roles
* Catalyzing reactions
Proteins serve a multitude of different functions in the body.
How many of the 20 amino acids are considered essential?
Ten
Essential amino acids cannot be synthesized by the human body.
What are essential amino acids?
Amino acids that cannot be synthesized by the human body and are required for normal functioning
Essential amino acids must be acquired through food.
How can non-essential amino acids be produced in the body?
They can be fabricated from carbohydrate sources via:
* Tricarboxylic acid cycle
* Glycolysis
* Pentose phosphate shunt
Non-essential amino acids are not required to be obtained from the diet.
List some non-essential amino acids.
Non-essential amino acids include:
* Alanine
* Asparagine
* Aspartate
* Cysteine
* Glutamate
* Glutamine
* Glycine
* Proline
* Serine
* Tyrosine
These amino acids can be synthesized by the body.
List some essential amino acids.
Essential amino acids include:
* Arginine
* Isoleucine
* Leucine
* Lysine
* Methionine
* Phenylalanine
* Threonine
* Tryptophan
* Valine
* Histidine
The classification of essential vs non-essential may vary between sources.
What is the basic structure of an amino acid?
The basic structure includes:
* Hydrogen atom
* Carboxyl group
* Amino group
* R side chain
The R side chain is specific to each amino acid and determines its properties.
What determines the properties of an amino acid?
The R side chain
The R side chain varies among different amino acids, influencing their polarity and other properties.
True or False: All amino acids are essential for human functioning.
False
Only essential amino acids cannot be synthesized by the body.
What is the primary structure of proteins?
Chains of individual amino acids linked together via peptide bonds
The order or sequence of amino acids determines the final structure of the protein.
How are polypeptide chains formed?
By three or more amino acids joined together by a covalent bond between the amino group of one amino acid and the carboxyl group of another amino acid
This forms a backbone in a repeating pattern of - N - C - C - N - C - C - N -.
What characterizes the secondary structure of proteins?
Folding chains of amino acids into a helix or sheet
Stabilized by hydrogen bonds.
What are the two main types of secondary structures?
- Helices
- Beta sheets
Helices have R side chains facing away from the center, while beta sheets can be parallel or anti-parallel.
What stabilizes secondary structures in proteins?
Hydrogen bonds
These bonds form between the backbone of the amino acids.
What is the tertiary structure of proteins?
The final, overall three-dimensional shape of the protein
It results from bonding between the side chains.
What types of bonding can occur in the tertiary structure of proteins?
- Hydrogen bonds
- Hydrophobic interactions
- Disulfide bonds
- Salt bridges
Electrostatic forces are also involved, attracting positively and negatively charged groups.
What are disulfide bonds?
Strong, covalent bonds that form when the sulfhydryl groups of cysteine become oxidized
They play a critical role in stabilizing the structure of proteins.
True or False: The primary structure of proteins is stabilized by hydrogen bonds.
False
The primary structure is determined by the sequence of amino acids, not stabilized by hydrogen bonds.
What are quaternary proteins classified as?
Globular or fibrous
What characterizes quaternary proteins?
Oligomeric (created through the bonding of several peptide units)
What are the general characteristics of globular proteins?
Compact, water-soluble, and ball-shaped
What is the primary function of most globular proteins?
They are enzymes
Give an example of a globular protein.
Hemoglobin
What are the characteristics of fibrous proteins?
Elongated, strong, and not water-soluble
What is the primary function of fibrous proteins?
They tend to serve a structural function
Give an example of a fibrous protein.
Collagen
What are acids regarded as?
Proton donors
What are bases considered?
Proton acceptors
What happens to strong acids in solution?
They completely ionize
What happens to weak acids in solution?
They only partially ionize
What does the ionization of an acid depend on?
Ka value (acid dissociation constant)
What is the formula for Ka?
Ka = [H+][A-]/[HA]
What does a higher Ka value indicate?
A greater amount of ionized acid
What is the relationship between Ka and pKa?
Inversely related
What is the formula for pKa?
pKa = -log(Ka)
What indicates a stronger acid, higher Ka or lower pKa?
Higher Ka or lower pKa
What does pH measure?
The concentration of hydrogen ions in a solution
What does a higher pH correspond to?
A more basic solution
What is the formula for pH?
pH = -log[H+]
