Semmelweis Entrance Exam Study Questions
With Complete Solutions
There are two patterns To be familiar with for secondary structure first pattern = alpha
helix; the Hydrogen bonds just run up and down this , Stabilizing this coiled structure
Second pattern = beta sheet; stabalized by hydrogen bonds.
parallel beta sheet : If you have the amino ends and the carboxyl ends line up
Anti parallel configuration: if you have a single polypeptide that wraps upon itself and have the
hydrogen bondsd stablizing, then you have the amino ends coming around and lining up with the
carboxyl end
Tertiary structure: higher order of folding within a polypeptide chain. Think of it as the
many folds within a polypeptide which then fold upon each other again.
This depends on distant group interaction so distant interactions.
Just like secondary structure, it is stabalized by hydrogen bonds but you can also have some
other interactions that come in to play such as van der waals interaction
There is also hydrophobic packing and also disulfide bridge formation.
hydrophobic packing: for example lets say we have a folding up polypeptide or protein, and this
protein is found within the wateryb polar environment of the interior of the cell
,Semmelweis Entrance Exam Study Questions
With Complete Solutions
So if we have water on the exterior of this protein then we will find all of the polar groups on the
exterior iterating with this water
Then on the interior you would find the nonpolar or hydrophobic group hiding from the water
disulfide bridge: describe an interaction that happens only between cystines
Cystines a type of amino acid (aa) that have a special thiol group as part of its side chain.
This thiol group has a sulfer atom that can become oxidized. when this oxidation occurs you get
the formation of a covalent bond between the sufler groups.
The formation of a dissulfide bridge happens on the exterior of a cell and you tend to see the
formation of separate thiol groups on the interior of a cell and that is because the interior of the
cell has antioxidants which generate a reducing environment
Since the exterior of a cell lacks these antioxidants you get an oxidizing environment
So if we were to ask you which environment favours the formation of disfulide bridges, you
would say the extracellular space does
quaternary structure: describes the bonding between multiple polypeptides.
The same interactions that determine tertiary structure play a role in quaternary
Example: lets say I have one folded up polypeptide, two folded up polypeptides and a third and a
fourth. The quaternary structure is described by the interactions between these four polypeptides.
,Semmelweis Entrance Exam Study Questions
With Complete Solutions
Within the completed protein structure, each individual polypeptide is termed a subunit.
Since this protein has four subunits, it is called a tetramer
If we were to have two subunits, it would me called a dimer
Three would be called a trimer
An anything above four is called a multimer
So the term for a completely properly folded up protein is called the proper conformation of a
protein and to achieve the proper confirmation you must have the correct primary structure,
secondary structure tertiary structure and quaternary structure and id any of these levels of
protein structure were to break down then yous start to have misfolding which can then
contribute to any of a number of disease states
Allostery The allosteric, or "other", site is the active site of an adjoining protein subunit.
The binding of oxygen to one subunit induces a conformational change in that subunit that
interacts with the remaining active sites to enhance their oxygen affinity
A classical example of allosteric control in protein kinases is cyclin binding to cyclin-dependent
kinases (CDKs), where cyclin binding induces a reformation of the ATP binding site [18].
The term allostery refers to the fact that the regulatory site of an allosteric protein is physically
distinct from its active site
Allostery in proteins influences various biological processes such as regulation of gene
transcription and activities of enzymes and cell signaling.
, Semmelweis Entrance Exam Study Questions
With Complete Solutions
Watch a video
Starch (Polysaccharides) found in plants, role to store energy, example found in potatos
2 kinds of plant strach:
1- amylose: made up of glucose monomers, forms a straght chain of glucose monomers, bond
that connects the glucose monomers is an alpha 1 4 glycosidic bond CH2OH
2 amylopectictin: contains branch structures, still has a straight chain but ocasionally , youll have
chains that will branch off from the main chain
Bonds in amylopectin: straight chain has the alpha 1,4 bond , the branch part has an alpha 1, 6
bond
So amylopectin contains two types of glycosidic bonds
alph and the beta forms of glucose. Alpha: form the OH group on the carbon 1, its facing
the downward direction
Beta form of glucose: has the OH group pointing up
glycogen An extensively branched glucose storage polysaccharide found in the liver and
muscle of animals; the animal equivalent of starch.
With Complete Solutions
There are two patterns To be familiar with for secondary structure first pattern = alpha
helix; the Hydrogen bonds just run up and down this , Stabilizing this coiled structure
Second pattern = beta sheet; stabalized by hydrogen bonds.
parallel beta sheet : If you have the amino ends and the carboxyl ends line up
Anti parallel configuration: if you have a single polypeptide that wraps upon itself and have the
hydrogen bondsd stablizing, then you have the amino ends coming around and lining up with the
carboxyl end
Tertiary structure: higher order of folding within a polypeptide chain. Think of it as the
many folds within a polypeptide which then fold upon each other again.
This depends on distant group interaction so distant interactions.
Just like secondary structure, it is stabalized by hydrogen bonds but you can also have some
other interactions that come in to play such as van der waals interaction
There is also hydrophobic packing and also disulfide bridge formation.
hydrophobic packing: for example lets say we have a folding up polypeptide or protein, and this
protein is found within the wateryb polar environment of the interior of the cell
,Semmelweis Entrance Exam Study Questions
With Complete Solutions
So if we have water on the exterior of this protein then we will find all of the polar groups on the
exterior iterating with this water
Then on the interior you would find the nonpolar or hydrophobic group hiding from the water
disulfide bridge: describe an interaction that happens only between cystines
Cystines a type of amino acid (aa) that have a special thiol group as part of its side chain.
This thiol group has a sulfer atom that can become oxidized. when this oxidation occurs you get
the formation of a covalent bond between the sufler groups.
The formation of a dissulfide bridge happens on the exterior of a cell and you tend to see the
formation of separate thiol groups on the interior of a cell and that is because the interior of the
cell has antioxidants which generate a reducing environment
Since the exterior of a cell lacks these antioxidants you get an oxidizing environment
So if we were to ask you which environment favours the formation of disfulide bridges, you
would say the extracellular space does
quaternary structure: describes the bonding between multiple polypeptides.
The same interactions that determine tertiary structure play a role in quaternary
Example: lets say I have one folded up polypeptide, two folded up polypeptides and a third and a
fourth. The quaternary structure is described by the interactions between these four polypeptides.
,Semmelweis Entrance Exam Study Questions
With Complete Solutions
Within the completed protein structure, each individual polypeptide is termed a subunit.
Since this protein has four subunits, it is called a tetramer
If we were to have two subunits, it would me called a dimer
Three would be called a trimer
An anything above four is called a multimer
So the term for a completely properly folded up protein is called the proper conformation of a
protein and to achieve the proper confirmation you must have the correct primary structure,
secondary structure tertiary structure and quaternary structure and id any of these levels of
protein structure were to break down then yous start to have misfolding which can then
contribute to any of a number of disease states
Allostery The allosteric, or "other", site is the active site of an adjoining protein subunit.
The binding of oxygen to one subunit induces a conformational change in that subunit that
interacts with the remaining active sites to enhance their oxygen affinity
A classical example of allosteric control in protein kinases is cyclin binding to cyclin-dependent
kinases (CDKs), where cyclin binding induces a reformation of the ATP binding site [18].
The term allostery refers to the fact that the regulatory site of an allosteric protein is physically
distinct from its active site
Allostery in proteins influences various biological processes such as regulation of gene
transcription and activities of enzymes and cell signaling.
, Semmelweis Entrance Exam Study Questions
With Complete Solutions
Watch a video
Starch (Polysaccharides) found in plants, role to store energy, example found in potatos
2 kinds of plant strach:
1- amylose: made up of glucose monomers, forms a straght chain of glucose monomers, bond
that connects the glucose monomers is an alpha 1 4 glycosidic bond CH2OH
2 amylopectictin: contains branch structures, still has a straight chain but ocasionally , youll have
chains that will branch off from the main chain
Bonds in amylopectin: straight chain has the alpha 1,4 bond , the branch part has an alpha 1, 6
bond
So amylopectin contains two types of glycosidic bonds
alph and the beta forms of glucose. Alpha: form the OH group on the carbon 1, its facing
the downward direction
Beta form of glucose: has the OH group pointing up
glycogen An extensively branched glucose storage polysaccharide found in the liver and
muscle of animals; the animal equivalent of starch.
