Lecture 1 Flashcards
Biochemistry
-Definition
It is the science of the chemical basis of life. It describes in molecular terms: structures, mechanisms, chemical processes shared by all organisms.
Prokaryotes
- Lack defined nucleus or internal membrane structures.
- Unicellular.
- Variety of shapes, sizes and living conditions.
- DNA is a single circular strand in nucleoid region.
Eukaryotes
- The nucleus consists of nuclear material enclosed within a double membrane.
- Single cell organisms or multicellular.
Covalent bond
It is a chemical bond that involves the sharing of electron pairs between atoms.
- Non- polar covalent bond
- Polar covalent bond
- Ionic bond
- Bonding electrons share equally between atoms. No charge.
- Bonding electrons share unequally between atoms. Partial charge.
- Complete transfer of one or more valence electrons. Full charge.
Functional roles of proteins
- Enzymes.
- Signalling.
- Gene regulation.
- Structural.
- Transport.
General structure of an amino acid
- Alpha carbon.
- Carboxyl group.
- Amino group.
- Side chain.
Non-polar amino acids
Polar amino acids
- Glycine, leucine, isoleucine, valine, tryptophan, methionine, proline, alanine, phenylalanine.
- Serine, threonine, tyrosine, cysteine, asparagine, glutamine.
Positively charged (basic).
Negatively charged (acidic).
- Histidine, lysine, argigine.
- Glutamic acid, aspartic acid
Chiral / Chiriality
An object that cannot be superimposed on its mirror image
- When can enatiomers occur?
- Which amino acid CANNOT occur in two isomeric forms?
- Only when there is 4 different attachments on the alpha carbon
- Glycine.
Which type of amino acids are manufactured in cells? D or L form?
L form.
What are essential amino acids? Give three examples.
They are essential in a diet and are not synthesized in the human body.
Ex: valine, leucine, lysine, histidine, isoleucine.
Amino acids are weak
Polyprotic acids
At neutral pH, amino acids are present as..
Zwitter ions
The strong prositive charge on the amino group induces…
a tendency for the carboxylic acid group to lose a proton.
Isoelectric point
pH value at which the net charge of a compound is zero.
Non- polar side chain
- Characteristics
- Name all of them (9)
-Hydrophobic, do not gain or loose protons, do not participate in hydrogen or ionic bonds.
GAVE YOU LIP PTM
Glycine, Alanine, Valine, Leucine, Isoleucine, Proline, Phenylalanine, Tryptophan, Methionine
Hydrophobic interactions
- Important for…
- In a hydrophobic environment, nonpolar side chain are located….
- Stabilizing the protein.
- Outside
Proline differs from other amino acids because…
- It has a five- membered ring.
- It contains a secondary amino group.
- Referred to as imino acid.
The polar hydroxyl group of serine, threonine, tyrosine and the carbonyl and amide group of asparagine and glutamine contribute to the formation of…
Hydrogen bonds
Disulfide bonds form when..
The -SH group of two cysteine undergo oxidation and form a S-S
Amino acids with uncharged polar side chains (6)
GIULIA AMA COMER TAPIOCA SEM TOFU
Glutamine, cysteine, threonine, tyrosine, serine, asparagine
Amino acids with acidic side chains (2)
- Name
- Characteristics.
-Aspartic and glutamic acid.
- Negatively charged at physiological pH.
- Proton donors
