Amino Acids and Proteins Flashcards
What are amino acids?
The basic structural units (molecules) of proteins
What is the basic structure of an amino acid?
An amino group
A carboxylic group
A distinctive R (side) chain
All bonded to a carbon atom
The R-group side chain defines which amino acid is which
How are amino acids classified?
Amino acids can be classified as:
- Essential
- Conditionally essential
- Nonessential
These classifications directly relate to whether or not an amino acid is synthesised by the body or taken from an outside source.
What are the qualities of essential amino acids?
- They are not synthesised by the body
- Sourced from diet eg eggs, meats, legumes, and beans
What are the qualities of conditionally essential amino acids?
Produced / synthesised by the body, except in times of illness or stress
-Backbone sourced form carbohydrates and fats, nitrogen sourced from other proteins
What are the characteristics of nonessential amino acids?
Produced / synthesised entirely by the body
Backbone sourced form carbohydrates and fats, nitrogen sourced from other proteins
What are peptides and how are they classified?
Short strings of 2 - 50 amino acids
Classified by the number of amino acids in a chain
- Dipeptide (2 amino acids)
- Tripeptide (3 amino acids)
- Polypeptides (More than 10 amino acids)
What are peptide bonds?
Peptide bonds link amino acids to form polypeptide chains
What are mutations of genetic code and what kinds are there?
Malfunctioning or absence or protein
Point mutations = silent, nonsense, and missense
Frame shift mutations = insertion/deletion of a number of bases that is NOT a multiple of three
What is a protein?
Molecules that consist of more than 50 amino acids and one or more polypeptide chain
What are signs of amino acid deficiency?
Loss of muscle mass Blood sugar fluctuation Weight gain Fatigue Frequent infection Hair loss Anxiety Depression Slow wound healing
What is the central dogma / the flow of genetic information?
Replication of DNA
Transcription to mRNA
Translation to protein made of amino acids
What are the components of translation?
mRNA Amino acids tRNA (adpater molecules) Ribosomes (action stations) Enzymes and energy
How is RNA written to reflect a protein?
Initiation = start codon AUG Elongation = addition of amino acids by peptide bonds Termination = stop codon UAA, UAG, UGA
What are the four levels of protein stucture?
Primary structure
Secondary structure
Tertiary structure
Quaternary structure
What is a protein’s primary structure?
A defined sequence of amino acids in a polypeptide
What is a protein’s secondary structure?
Regular, recognisable conformations observed in the polypeptide such as an alpha-helix
What is a protein’s tertiary structure?
Three dimensional structure of entire folded protein
Polypeptide chain
What is a protein’s quaternary structure?
Assembled subunits into a protein complex
Only in proteins with more than 1 polypeptide chain
What is denaturation?
Any alteration / mild disruption in the sturcture that changes the biological, chemical, and physical properties of the protein
Primary structure remains unchanged by denaturation
What is the difference in the functions of enzymes and hormones?
Enzymes speed up reactions in the body eg digestive enzymes
Hormones direct specific activities such as regulating blood glucose levels (insulin)
What are the functions of antibodies?
Involved in immune system to defend the body from antigens
How do proteins provide structural and mechancial support?
Provide strength and flexibility to body tissues essential for the ongoing maintenance of the body
How do proteins affect carriers and transport nutrients?
Shuttle substances such as oxygen, nutrients, and waste products through the blood and out of cells
How do proteins help with fluid balance?
Ensure that body fluids are evenly dispersed in the blood and inside / outside cells
How do proteins help with acid base balance?
Acts as buffers to help keep the pH of body fluids wihtin a tight range
What is the function of proteins regarding energy?
Provides calories, can be used as energy when necessary
What are the specialised roles of amino acids?
- Chemical messengers (neurotransmitters)
- Potent local mediator of allergic reactions eg histamine
- Thyroid hormone
- Intermediates in various metabolic processes
