Proteins (2) Flashcards
Globular protein examples and function
Enzymes, haemoglobin and hormones are globular proteins and their function is metabolic.
What do globular proteins do and are they soluble
Globular proteins are soluble and they fold into a 3D shape
Why are globular proteins soluble
Globular proteins are soluble because the r groups are hydrophilic as they are polar so they react with water.
Fibrous proteins examples and function
Fibrous proteins examples include keratin and collagen in hair and nails. Their roles are structural.
Fibrous proteins characteristics
Fibrous proteins are insoluble and the strands lay side by side.
How many polypeptide bonds does collagen have
Collagen has 3 polypeptide bonds and it has many H bonds
What is the difference in structures of fibrous and globular proteins
Globular proteins have an irregular sequence whereas fibrous proteins have a repetitive amino acid structure and form long polypeptide chains, cross links occur between polypeptide chains
What is the structure of haemoglobin
Structure of haemoglobin is:
Haemoglobin is a globular protein.
Haemoglobin is soluble so it can be easily transported in the blood. It is soluble because of the hydrophilic R groups on outside.
Conjugated protein as it has 4 haem groups containing iron which can bind to 02
What is collagen structure
Collagen structure is:
Collagen is fibrous protein
It has a repetitive sequence of amino acids in primary structure
Collagen molecule consists of 3 polypeptides chains in a loose helix held by peptide bonds.
Chains are coiled around each other and cross linking occurs between chains
Strong protein with high tensile strength forms connective tissue in animals.
What are peripheral protein
Peripheral proteins are proteins which are loosely attached on outside surface of the membrane
What are integral proteins
Integral proteins are proteins which care fully embedded within phospholipids, some span both layers.
How does primary structure affect protein shape
Primary structure affects protein shape because Sequences of bases in DNA determines sequence of bases in mRNA codon produced which determines which tRNA molecule which is brought to ribosome which affects amino acid added to polypeptide chain. Determines sequence of amino acids and R groups present. R groups determine bonding which determines folding and tertiary structure.
Function of a carrier protein in a cell membrane
Function of carrier protein in cell membrane is:
Carrier proteins aid facilitated diffusion because polar and large molecules cannot travel through membrane.
Carrier proteins are also needed in active transport where they use ATP to move substances against a concentration gradient.
What are similarities and differences between an enzyme and collagen
Similarities are:
Both chains of amino acids joined by peptide bonds
Both have bonds involved in holding molecule in 3D shape
Differences
Enzyme is folded in tertiary structure whereas collagen has long chains with cross links
Enzymes have hydrophilic groups on surface whereas collagen doesn’t
