Proteins

Question 1

what are polypeptides

Answer 1

chains of amino acids that are made through condensation reactions that happen in the ribosome
main component of proteins

Question 2

what is a lysozyme

Answer 2

enzyme composed of only one polypeptide chain found in nasal mucous and tears

Question 3

what is integrin

Answer 3

membrane protein with 2 polypeptides

each has a hydrophobic portion embedded in the membrane

Question 4

what is collagen

Answer 4

composed of 3 polypeptides

Question 5

what determines the conformation of a protein

Answer 5

aa sequence of its polypeptides

2 mains shapes -> fibrous and globular

Question 6

what is the primary structure of a polypeptide chain

Answer 6

the number and sequence of aas determined by base sequence in DNA

Question 7

what is the secondary structure of a polypeptide chain

Answer 7

regular repeated structures in chain of aas

• -> beta-pleated sheets
• -> alpha helices

Question 8

what is the tertiary structure of a polypeptide chain

Answer 8

3D shape of one polypeptide chain stabilised by intermolecular bonds

Question 9

what is the quaternary structure of a polypeptide chain

Answer 9

linking together 2 or more polypeptides or linking of polypeptide chain with a prosthetic group (haemoglobin)

Question 10

list functions of proteins

Answer 10

catalysis
muscle contraction
tensile strengthening
transports of nutrients and gases
membrane transport
hormones
immunity

Question 11

what is a proteome

Answer 11

all of the proteins produced by a cell/tissue/organism

different cells make up different proteins so it varies over time

Question 12

what is a genome

Answer 12

all of the genes of a cell/tissue/organism (all cells have same genes)

Question 13

what is denaturation

Answer 13

a change in the confirmation of the protein

- shape of molecule

Question 14

what makes proteins denature

Answer 14

effect of temperature

effect of pH

Question 15

how does substrate concentration affect the activity of enzymes

Answer 15

at low substrate concentration: random collisions between substrate and active site are rare
high substrate concentration: active sites are all occupied so increasing concentration has little effect on activity

Question 16

how are amino acids linked

Answer 16

peptide bonds forming a long chain

Question 17

list 3 key examples of protein function

Answer 17

rubisco (ribulose bisphosphate carboxylase: catalyses fixing of carbon dioxide providing it to cells for photosynthesis and found in large concentrations in leaves/algal cells

insulin: hormone secreted in pancreas and transported by blood
immunoglobulins: Y-shaped and have two antigen bonding sites (one on each arm) specific to the antigens on the corresponding pathogen while the other parts cause a response (marker for phagocytotic engulfing)