Lec 4. Macromoluecules II: proteins and nucleic acids

Question 1

Protein

What are the steps in which proteins are built from

Answer 1

One or more polypeptides with a specific 3-D conformation

Amino Acids to polypeptides to proteins

Question 2

What are proteins responsible for?

Answer 2

support, storage, transport, signaling, receptors, movement, catalysis, defense

Question 3

Amino Acid structure

Answer 3

1) (Alpha) carbon
2) Hydrogen
3) Carboxyl group
4) Amino group
5) R group

Question 4

How are polypeptides formed?

Answer 4

AA are joined by dehydration reactions called peptide bonds (covalent)

H from amino group and OH from carboxyl group are removed to form a bond

Bond is between the C (C terminus) and N (N terminus)

Question 5

Primary structure

Answer 5

The AA sequence

Proper folding is crucial!

Question 6

Secondary Structure

Answer 6

Hydrogen bonding between atoms in the polypeptide

Composed of A helix (COILS) and B pleated sheets (FOLDS)

Question 7

Tertiary Structure

What are some weak/strong bonds between R groups

Answer 7

The overall structure/shape of polypeptide made by R group interactions

W: H bonds, ionic, Van der wals
S: Covalent (disulfide)

Question 8

Quatenary Structure

Why do some proteins not have this?

Answer 8

Overall protein structure resulted form combined poplypeptides (2 or more polypeptides)
Also stabilized by R group interactions

Some proteins only have 1 polypeptide chain

Question 9

What is protein conformation (overall shape of protein) influenced by?

Answer 9

• Chaperone proteins promote proper folding by providing a good environment
• pH, high salt concentration, temperature

Question 10

What happens to damaged/unusable/misfolded proteins (Process)
What is the result of an abnormal proteasome?

Answer 10

1. tagged with ubiquitin (kiss of death)
2. Tagged proteins delivered to proteasomes (PROTEIN GARBAGE CAN)
3. Proteasomes chop proteins into short peptides for recycling

Abnormal proteosomes= cancer, cycstic firbrosis, neuro. diseases

Degraded proteins hydrolyzed back to amino acids which can be reused (google)

Question 11

Nucleic acids

Function, structure, types

Answer 11

AKA polynucleiotide
Function: store and transmit heriditary info
Strcture: polymers of nuceiotide monomers WHICH INCLUDE Nitrogenous base, phopshate group (backbone), 5’ (pentose) sugar
Types: DNA, RNA

Question 12

Purines/pyramidines

Which of the bases are pyrmadines/purines

Answer 12

Purines: 2 carbon rings (A,G)
Pyramidines: 1 carbon ring (C,T,U)

Question 13

Explain how sugar-phosphate backbone of nucleic acids work

Answer 13

• Sugar connected to phosphate group of adjacent nucleiotide and linked by phosphodiester bonds
• Side chains include nitrogenous bases (Purines, and pyramidines)

Question 14

Proteins are constructed from same __________

Answer 14

20 amino acids

Question 15

R group

Answer 15

Variable side chain of amino acids (20 types for 20 different amino acids)

Question 16

Deoxyribonucleic acid vs ribonucleic acid

Answer 16

Ribose contains a hydroxyl (OH) at position 2 whereas deoxyribose has a H at position 2

deoxy=without an oxygen