Lecture 3 - Proteins Intro

Question 1

Proteins are

Answer 1

non-branching polymers

that form macromolecules about 50 - 100 Å in size (1Å = 10-10 m).

Question 2

Each protein is composed of

joined together how

Answer 2

specific sequence of amino acids joined together by chemical bonds called peptide bonds.

Question 3

How many amino acids are used to make proteins?

Answer 3

20 different amino acids

Question 4

ways to determine protein structures are

Answer 4

Protein crystallography
Electron cryo-microscopy
NMR spectroscopy

Question 5

Ways to depict a chemical structure

Answer 5

Skeletal
Ball & Stick
Space-Filling

Question 6

Protein functions

Answer 6

• Cell signalling - hormone (Insulin)
• Metabolism & Digestion (Alcohol dehydrogenase & Hexokinase)
• Oxygen transport - metabolism (haemoglobin)
• Protein digestion (Trypsin)
• Immune protection
• Membrane proteins - Energetics (ATP Synthase)
• Replication & Maintenance (DNA polymerase & RNA Polymerase)

Question 7

Cell signalling - hormone

Answer 7

After a meal insulin is generated

binds to insulin receptor to signal cells to take up glucose.

Question 8

Metabolism and Digestion

Answer 8

Alcohol Dehydrogenase

Hexokinase

Question 9

Alcohol dehydrogenase

Answer 9

enzyme that helps to metabolise ethanol.

Enzymes catalyse biochemical reactions.

Metabolism

Question 10

Hexokinase

Answer 10

enzyme that adds a phosphate to glucose,
after glucose is taken up by the cell.

Kinases are enzymes that usually add phosphate to molecules

Digestion

Question 11

Oxygen transport - metabolism

Answer 11

Haemoglobin binds oxygen in the lungs and carries

it in the blood to tissues for use in metabolism

Question 12

Protein Digestion

Answer 12

Trypsin is an enzyme that breaks down proteins during digestion.

Enzymes that breakdown proteins are called proteases

Question 13

Immune protection

Answer 13

Antibodies bind to cellular invaders (bacteria and viruses) to help protect the body from infection.

Question 14

Membrane proteins - Energetics

Answer 14

ATP synthase is a membrane protein that generates ATP for use in cellular functions.

Question 15

DNA polymerase

Answer 15

binds to one strand of DNA and adds the complementary strand to it.

Replication & Maintenance

Question 16

RNA polymerase

Answer 16

creates a single strand of RNA that is complementary to one of the strands of duplex DNA

Replication & Maintenance

Question 17

Structure helps us understand

Answer 17

how proteins work

Question 18

HIV Protease

Answer 18

Viruses and bacteria make proteins. They use the same amino acid building blocks. HIV makes a protease that is essential for HIV replication.

May include a bound inhibitor.

Question 19

What are proteins polymers of?

Answer 19

Amino acids

Question 20

How many different standard amino acids are there?

Answer 20

20

Question 21

What is the name of the bond that links amino acids in the polypeptide chain?

Answer 21

Peptide bonds

Question 22

Does each protein have an unique sequence of amino acids? Explain.

Answer 22

Yes, Determines the protein primary structure and helps us understand their function.