Lecture 11 - Introducton to Proteins

Question 1

some prokaryotes use ________ for _________ which are ______-_____ structures protruding from the cell surface

Answer 1

flagellum

locomotion

thread-like

Question 2

why does the smooth ER look smooth and what is it rich in and for what?

Answer 2

because it lacks ribosomes, it is rich in enzymes for metabolic processes

Question 3

ribosome composition:

Answer 3

composed of two subunits that combine to attach to messenger RNA (mRNA) and carry out protein synthesis

Question 4

Cell types that synthesize large quantities of proteins have:

Answer 4

large numbers of ribosomes and prominent nuclei

Question 5

lysosomes:

Answer 5

membrane-bound vesicles containing digestive enzymes

Question 6

average protein molecule size:

Answer 6

1-5 nm

Question 7

the word “Protein” is derived from the Greek word:

Answer 7

proteios which means “of the first rank” in order to emphasise the importance of this class of molecules

Question 8

how many amino acids are there?

Answer 8

20

Question 9

Transcription:

Answer 9

conversion of information from DNA to mRNA

Question 10

Translation:

Answer 10

conversion of information from RNA to protein

Question 11

protein chains always begin with:

Answer 11

Met (AUG)

Question 12

generic zwitterion structure:

Answer 12

+H3N—CHR—COO-

Question 13

each “r-group” has a different:

Answer 13

chemical property - large, small, positive, negative, hydrophobic, hydrophilic

Question 14

that does the fact that R-Groups either want to be near or far from one another drive?

Answer 14

the affinity and repulsion of different interacting R-Groups drives protein folding

Question 15

what can protein strands form?

Answer 15

helices, strands & coils

Question 16

the diverse functions of protein:

Answer 16

enzymatic catalysis, transport, storage, mechanical support, immune protection, generation and transmission of nerve impulses, control of growth and differentiation, toxins, cascade proteins, antifreeze, GFP & adhesives

Question 17

types of protein structure:

Answer 17

transmembrane, globular, fibrous & natively unfolded

Question 18

globular proteins:

Answer 18

largest type of proteins

• Enzymes
• Immune system proteins
• Cell adhesion proteins
• DNA-binding proteins
• Carrier proteins

Question 19

natively unfolded:

Answer 19

signalling peptides - neurotransmitters

Question 20

representing protein structure:

Answer 20

• polypeptide chain - a chain of amino acids folds into a compact structure
• made up of distinct structural motifs

Question 21

all amino acids exist as:

Answer 21

zwitterions

Question 22

three forms of protein modelling:

Answer 22

(1) carbon backbone only

(2) + all side-chains

(3) Van De Waals- space filling

(4) secondary structure

Question 23

all protein images are programmed via:

Answer 23

• a coordinate file from the “Protein DataBank” [PDB file]
• looks like a spreadsheet filled with data that is processed by an algorithm to build a three dimensional structure
• some column titles being: type no, atom acid, atom, amino acid, amino, x, y, z, occupancy & b-factor

Question 24

how do proteins accomplish so many functions?

Answer 24

through forming a multitude of shapes, interacting with other molecules with high specificity