1A Biological Molecules Flashcards
Proteins
Polymers made up of the monomers amino acids.
Structural levels of proteins
Primary
Secondary
Tertiary
Quaternary
What is the primary structure determined by?
The order of bases in a gene determine the sequencing of amino acids in a polypeptide chain.
Where do the hydrogen bonds in the secondary structure of a protein form?
Between the negatively charged C=O of the carboxyl group of one amino acid and the positively charged H of the amino group of another amino acid.
Tertiary structure
- the further folding of the secondary structure
- to form a unique 3D shape
- held in place by ionic, hydrogen and disulfide bonds
Where do the bonds in the tertiary structure form?
Between the R groups of different amino acids.
Disulfide bonds only occur between two sulfur atoms in the R group (cystein)
Quaternary structure
A proteins made up of more than one polypeptide chain.
e.g. Hb
What happens if a protein is denatured?
The bonds which hold the tertiary and secondary structure in shape break, and therefore the unique 3D shape is lost.
This 3D shape is critical to a proteins function.
What can cause a protein to denature?
• too high temperature
• changes in pH
ionic - changes in pH
hydrogen - heat, acidity
Prosthetic group
The molecule incorporated in a conjugated protein
Conjugated protein
Protein molecule joined with another molecule called a prosthetic group
Lipoproteins
Conjugated proteins with a lipid prosthetic group
Glycoprotein
Conjugated proteins with a carbohydrate prosthetic group
Proteases
protein-digesting enzymes
Peptide bond
The bond formed by condensation reactions between amino acids
Compare the energy storage capabilities of lipids and carbohydrates
Lipids (especially triglycerides) can store about 3x as much energy as the same mass of carbohydrates
What type of protein is collagen?
Fibrous protein
Where in the human body is collagen found?
• skin
• matrix of bones
• tendons
In what body structures is keratin found?
Hair
Nails
anion
a negative ion
cation
a positive ion
ionic bonds
bonds formed when atoms give or receive electrons; they result in charged particles called ions
covalent bond
bonds formed when atoms share electrons; covalent molecules may be polar if the electrons are not shared equally
dipole
the separation of charge in a molecule when the electrons in covalent bonds are not evenly shared
polar molecule
a molecule containing a dipole
dissociation
splitting of a molecule into smaller molecules, atoms, or ions, especially by a reversible process
hydrogen bonds
weak electrostatic intermolecular bonds formed between polar molecules containing at least one hydrogen atom
monomer
a small molecule that is a single unit of a larger molecule called a polymer
polymer
a long-chain molecule made up of many smaller, repeating monomer units joined together by chemical bonds
macromolecule
a very large molecule often formed by polymerisation
monosaccharide
a single sugar monomer
disaccharide
a sugar made up of two monosaccharide units joined by a glycosidic bond, formed in a condensation reaction
polysaccaride
a polymer consisting of long chains of monosaccharide units joined by glycosidic bonds
triose sugar
a sugar with 3 carbon atoms
pentose sugar
a sugar with 5 carbon atoms
ribose
a pentose sugar that is part of the structure of RNA
deoxyribonucleic acid
a nucleic acid that is the genetic material in many organisms
deoxyribose
a pentose sugar that is part of the structure of DNA
ribonucleic acid
a nucleic acid which is the genetic material in some organisms and is involved in protein synthesis
hexose sugar
a sugar with 6 carbon atoms
isomers
molecules that have the same chemical formula, but different molecular structures
glycosidic bond
a covalent bond formed between two monosaccharide units
reducing sugar
sugars that react with blue Benedict’s solution and reduce the copper(II) ions to copper(I) ions giving an orangey-red precipitate
non-reducing sugar
sugars that do not react with Benedict’s solution
oligosaccharides
molecules with between 3 and 10 monosaccharide units
ATP
adenosine triphosphate, the molecule that acts as a universal energy supply molecule in all cells
amylose
a complex carbohydrate containing only alpha glucose monomers joined together by 1,4-glycosidic bonds so the molecules form long unbranched chains
end products
the final products of a chemical reaction
amylopectin
a complex carbohydrate made up of alpha glucose monomers joined by 1,4-glycosidic bonds with some 1,6-glycosidic bonds so the molecules branch repeatedly
ester bonds
bonds formed in a condensation reaction between the carboxyl group (-COOH) of a fatty acid and one of the hydroxyl groups (-OH) of glycerol
glycogen
a complex carbohydrate with many alpha glucose units joined by 1,4- glycosidic bonds with many 1,6-glycosidic bonds, giving it many side branches
saturated fatty acid
a fatty acid in which each carbon atom is joined to the one next to it in the hydrocarbon chain by a single covalent bond
unsaturated fatty acid
a fatty acid in which the carbon atoms in the hydrocarbon chain have one or more double covalent bonds in them
monounsaturated fatty acid
a fatty acid with only one double covalent bond between carbon atoms in the hydrocarbon chain
polyunsaturated fatty acid
a fatty acid with two or more double covalent bonds between carbon atoms in the hydrocarbon chain
esterification
the process by which ester bonds are made
dipeptide
two amino acids joined by a peptide bond
collagen
a strong fibrous protein with a triple helix structure
denaturation
the loss of the 3D shape of a protein (e.g. caused by changes in temperature or pH)
describe 2 structural features of insoluble proteins
- long chains of amino acids
- repeating sequences of amino acids
- parallel chains held with cross links / by hydrogen bonds
Which type of fatty acids has more hydrogen atoms?
the more hydrogen atoms a fatty acid has the more saturated it is
which fatty acids are bad for health?
saturated (single bonds only)
describe the structure of collagen
• fibrous protein
• composed of three polypeptide chains (triple helix)
• held by hydrogen bonds between the chains
• repeating sequence of glycine (every third amino acid is glycine)
describe the structure of collagen
• fibrous protein
• composed of three polypeptide chains (triple helix)
• held by hydrogen bonds between the chains
• repeating sequence of glycine (every third amino acid is glycine)
three types amino acids found in collagen
- glycine
- proline
- hydroxyproline
what type of proteins is soluble in water?
globular proteins
what type of protein is insoluble in water?
fibrous proteins
what is the most common structural protein found in animals?
collagen
what type of protein is Hb?
globular protein
when does water reach its max. density?
at 4*C
what type of bonds joins monosaccharides?
glycosidic bond
ester bond
bond formed in a condensation reaction between a glycerol molecule and a fatty acid
peptide bond
bond formed in a condensation reaction between two amino acids to form a dipeptide
examples of fibrous proteins
collagen
keratin
elastin
examples of globular proteins
haemoglobin
insulin
lysozyme
condensation reaction
when two molecules join together with the formation of a new chemical bond and the release of a water molecule
hydrolysis reaction
a reaction that breaks the chemical bond between monomers using a water molecule
what monosaccharides is sucrose made of?
glucose
fructose
what monosaccharides is lactose made of?
glucose
galactose
what monosaccharides is maltose made of?
two alpha glucose monomers
give 3 monosaccharides
glucose, galactose, fructose
give 3 disaccharides
lactose, maltose, sucrose
give 3 polysaccharides
glycogen, starch, cellulose
draw the general structure of an amino acid
draw the general structure of a fatty acid
