types of protein Flashcards
state some features of globular proteins
-soluble in water
-spherical shape
-complementary to a specific molecule
-hydrophilic R groups on the surface
-irregular amino acid sequence
-contain prosthetic grouups-conjugated proteins
- have a functional role-in cellular processes
-temperature ,pH sensitive
state features of fibrous proteins
-insoluble in water
-elongated shape, form long strands
-regular amino acid sequence
-have structural functions,provide strength and support to tissues
-strong and tough
-unreactive
-flexible
what are the two types of protein
-globular proteins
-fibrous proteins
describe how globular protein fold into their tertiary structure
when a protein folds into their tertiary structure ,the hydrophobic R group clumb together on the inside of the protein,away from the aqueous environment and hydrophilic R groups are pushed on the outside of the protein,allowing globular protein to be soluble in water
state 3 example of globular proteins
-catalase
-haemoglobin
-insulin
state 3 examples of fibrous proteins
-collagen
-elastin
-keratin
what is a conjugated petein
-its a globular protein that contains a non-protein component known as a prosthetic group
what is a prosthetic group
a non-protein component that forms a permanent feature of a protein
what are the 3 different types of prosthetic groups
-lipids and carbohydrates can acts as prosthetic groups,they combine with proteins to form lipoproteins and glycoproteins
-metal ions like iron ions in haemoglobin
-molecules deprived of vitamins can act as prosthetic groups
what is a cheat code for how you compare proteins
SSAFES
-S for shape
-S for structure
-A for amino acid sequence
-F for function
-E for examples
-S for solubility
compare fibrous and globular proteins
shape:
globular proteins have a spherical shape whereas fibrous proteins have an elongated shape,form long strands
function:
globular proteins are water soluble,allowing them to perform functions within the body such as enzymes, transport proteins and hormones,whereas fibrous proteins are insoluble in water so pervorm more structural roles in the body ,providing strength and support to tissues
-amino acid sequence ; regular amino acid sequence in fibrous proteins and irregular in globular proteins
examples:
haemoglobin,catalase and insulin for globular VS collagen,elastin and keratin for fibrous
solubility:globular proteins are water soluble,whereas fibrous protein are not
how does the structure of globular proteins affect their function
the spherical shape allows them to bind to complementary molecules and perform specific functions like catalysing a reaction
how does the structure of fibrous proteins affect their function
-elongated shape,forming strong and tough strands allows them to provide strength and support to tissues
compare haemoglobin and elastin
haemoglobin is a globular protein whereas elastin is a fibrous protein
shape:
haemoglobin has a spherical shape whereas elastin has an elongated shape and it forms long strands
structure:
haemoglobin is a quaternary protein ,it consists of 4 polypeptide chains,2 sets of 2 identical subunits,2 alpha and 2 beta subunits
-haemoglobin is also a conjugated protein,it contains 4 prosthetic haem groups,one for each of its subunits
Elastin is also a quaternary protein,but it is not a conjugated protein and does not contain prosthetic haem group.Elastin is made of stretchy molecules called tropoelastin.They make elastin flexible and give it the ability to streach and recoil to its original size.
Elastin also has cross-linked structure which makes it very strong
amino acid sequence:
elastin has regular amino acid sequence whereas haemoglobin does not
function:
haemoglobin is water soluble so its function is of a transport protein,it binds to ,carries and transports oxygen molecules from the lungs to each cell in the body via the bloodstream- the Fe2+ ions within the haem group bind reversible with oxygen molecules to form oxyhaemoglobin,allowing the oxygen to be transported around the body
Elastin on the other hand is not water soluble so has a more structural role in the body.It is contained within arterial walls to provide it with strength and support, and flexibility ,allowing them to stretch and recoil to its original size without breaking
elastin also present in aleveoli in lungs
solubility:
haemoglobin has hydrophilic R groups on its surface so its soluble whereas elastin is insoluble due the many hydrophobic R groups
compare keratin and insulin
insulin is a globular protein whereas keratin is a fibrous protein
shape
insulin has a spherical shape,complementary to specific cell-surface receptors
whereas keratin has an elongated shape,form long strong ,tough inflexible strands
structure: insulin is made of 2 polypeptide chains,held together by disulphide bonds
keratin also contains many disulphide bonds between Rgroups containing sulfur,this makes it strong and inflexible
amino acid sequence: insulin has an irregular amino acid sequence whereas keratin has a regular amino acid sequence, large part of it consisting of cysteine amino acids
function: insulin is soluble in water,allowing to have an important role as a hormone,(as hormones are transported in the blood which is largely mad of water)it is involved in the regulation of blood glucose concentration in the body
whereas keratin has a more external structural role, Keratin strengthens and provides support to hair,nails and skin
keratin can be flexible ,but in the skin,not in the hair and nails ,there its inflexible
solubility: insulin is soluble in water as has hydrophilic R groups on its surface,whereas keratin is insoluble due the many hydrophobic R groups