Proteins B1.2 Flashcards
What is the basic amino acid structure?
amine group (-NH2) on the left, carboxyl group (-COOH) on the right, both bonded to the alpha carbon in the middle. The alpha carbon is also bonded to a hydrogen and R-group on the top and bottom.
The amine group of an amino acid and what does it do?
can become protonated to form NH3+. is basic because of accepting protons
The carboxyl group of an amino acid and what does it do?
can donate protons and is acidic because of that.
joins with the amine group of another amino acid in condensation to form peptide bond.
Amino acids are the what of proteins?
monomers
Condensation of amino acids
-OH of carboxyl group combines with the -H of the amine group of another amino acid to form a C-N peptide bond and water.
Oligopeptide?
anything 3-20 amino acids in a chain. polypeptide is more than 20
Protein is a what?
combination of polypeptides
What are essential amino acids?
can’t be synthesized by the body and must be obtained through food.
What are non-essential amino acids?
can be made from other amino acids.
What are conditionally essential amino acids?
are usually not essential + can be synthesized but in times of illness and stress will be unable to make and need it.
How many of the amino acids is essential? Where do they come from?
9/20
animals and dairy products
Vegan diets and amino acids?
vegan diets require attention to ensure essential amino acids are consumed because plants often do not have the same amino acids needed in one go
How are amino acids made?
the amino acid sequence of each polypeptide is store in a coded form in the base sequence of a gene (DNA). Goes through transcription and translation to create the RNA to which tRNAs bring the amino acids to.
Transcription in protein synthesis
copying the DNA code into an mRNA molecule
Translation in protein synthesis
changing mRNA sequence (codons) into amino acids (tRNA brings)
Where is the ribosome (to which the synthesis happens) in the cell?
located freely in cytoplasm OR membrane bound and associated with the rough ER.
What is the unique shape of every protein caused by?
the type of amino acid and the R-group. structure is determined by the base sequence
What does R-groups say about the amino acid?
it’s polarity
Haemoglobin
in red blood cells to transport oxygen
Immunoglobin
antibodies that bind to antigens (foreign) bacteria or pathogens to defend against them
Rhodopsin
absorbs photons of light and has light sensitive pigment to see in eyes.
Collagen
structural component of teeth, bones, and tendons. rope like, abundant
Keratin
found in hair has high tensile strength used as structural building block
Digestive enzymes
break down macromolecules to their monomers
Insulin
reduces glucose concentration in blood
Denaturation of proteins by?
heat and pH change
What type of interaction does the 3D structures of protein have with each polypeptide?
hydrogen bonds which are weak or interactions between the R groups.
- easily broken via heat or pH
Denaturalization via heat
vibrations in molecule break the bonds that make the polypeptide chains unfold and change shape.
Denaturalization via pH
changes in pH means changes in attraction between R groups of the polypeptide/protein. the attractions are important for the shape of the protein
Albumen in egg white
added heat break hydrogen bonds in egg making it cross-linked between sulfur R groups since water is trapped inside structure make INSOLUBLE.
Denaturation is?
permanent and forms insoluble precipitate
