Proteins

Question 1

What are some functions of proteins?

Answer 1

-Enzymes to catalyze synthesis of carbohydrates in mitochondria
-Structure of an organism
-Structures that move individual cells, large cargo, or molecules within cells
-Cell-cell signalling
-Antibodies to destroy viruses and bacteria

Question 2

What is the nucleus

Answer 2

Contains DNA, has a double membrane

Question 3

What is the nucleolus

Answer 3

produces and assembles ribosomes and transcribes rRNA

Question 4

Describe the nuclear envelope

Answer 4

-Non fluid
-Contains nuclear pore complexes to move material in and out (RNA, enzymes, DNA building materials)
-Double membrane

Question 5

Where are ribosomes located

Answer 5

-In cytosol
-Attached to endoplasmic reticulum

Question 6

How do amino acids bond to form polypeptides

Answer 6

-Formed by condensation or broken by hydrolysis
-Peptide bonds between carboxyl and amino groups of 2 amino acids

Question 7

What determines amino acid properties and 3D folding shape

Answer 7

Side chains

Question 8

What is a primary structure

Answer 8

Simple sequence infromation

Question 9

What are the 2 secondary structures

Answer 9

Alpha helix
-Amino and carboxyl groups attached by peptide bonds
-Coiled by hydrogen bonds between carbonyls and carboxyls

Beta Pleated Sheet
-Parallel protein strands with hydrogen bonds between carboxyl and amino groups of adjacdent strands

Question 10

What is a tertiary structure

Answer 10

3D shape formed by bonds between R groups

Shape formed by secondary structures and side chain interactions

Contains hydrogen bonds, van der waal interactions, covalent and ionic bonds, disulfide bonds, hydrophobic interactions

Question 11

What assists with protein folding

Answer 11

Molecular chaperones
-Bind to hydrophobic regions and prevent incorrect folding

Chaperonins
-Molecule complexes that act as isolation chambers for a forming polypeptide

Question 12

What is a quaternary structure

Answer 12

Assembly of polypeptide subunits that form the final functional protein

Question 13

What is found in the endomembrane system

Answer 13

Nuclear envelope, endoplasmic reticulum, lysosomes, gilgi apparatus

Question 14

How does a polypeptide enter the endoplasmic reticulum lumen

Answer 14

-Sequence causes ribosome to attach to ER
-It binds a signal recognition particle which then binds to a SRP receptor in the ER membrane
-The polypeptide then goes through a channel into the lumen

Question 15

What is glycolysation

Answer 15

The addition of carbohydrate chains which helps with protein stability, folding, and cell-cell recognition

Question 16

Which proteins end up in the cell membrane

Answer 16

porins and receptors

Question 17

Which proteins exit the cell

Answer 17

Antibodies, hormones, enzymes

Question 18

How do proteins get to their destinations

Answer 18

Tags allow them to be transported a certain way (often by transport vesicles) and released

Question 19

What are plasmids

Answer 19

Circular Prokaryotic DNA containing 1 or 2 genes that replicate independently and transfer between cells

Question 20

Describe Fred Neufeld experiment

Answer 20

Observed virulent (S) and non-virulent (R) strains of streptococcus pneumoniae, s-strain produces a smooth carbohydrate coating that masks the bacteria from the immune system and r-strain does not

Question 21

Describe Frederick Griffith experiment

Answer 21

Heated and exploded virulent bacteria leaving macromolecules intact, mixed exploded s-strain with r-strain and it resulted in death. Therefore, r-strain transformed into virulent strain

Question 22

Desccribe Avery McCarty, MacLeod experiment

Answer 22

Made heat killed virulent strain samples, added r-strain to each with a different enzyme that would destroy a particular molecule.
By process of elimination, mouse lived when DNA was destroyed therefore DNA is the hereditary material

Question 23

What defines non-polar side chains

Answer 23

-Hydrophobic
-Includes hydrocarbon chains or benzene
-Ex. Alanine, valine, leucine, isoleucine, methionine, phenylalanine, tryptophan, tyrosine

Question 24

What defines a polar side chain

Answer 24

-Hydrophilic
-Can form H-bonds
-ex. lysine, arginine, histidine, aspartic acid, glutanic acid, asparagine, glutamine, serine, threonine

Question 25

What is a monogenic disease

Answer 25

Caused by a mistake in 1 gene (ex. cystic fibrosis)

Question 26

Symptoms of cystic fibrosis

Answer 26

-cough
-wheezing
-thick mucus
-respiratory infections
-constipation
-salty sweat
-Impacts lungs and digestion

Question 27

DIfference between healthy and CF airways

Answer 27

Healthy: movement, pink colour, cartilage, clear mucus, capillaries

CF: Inflammed capillaries, narrow airways, thick yellow mucus (must be removed through aspiration to prevent infection)

Question 28

What causes cystic fibrosis symptoms

Answer 28

Incorrect unbalanced transport of ions and water across the cell membranes, resulting in maany ducts being compromised

Question 29

How do ciliated cells work

Answer 29

Sweep in the same direction, covered by airway surface liquid, undercurrent sweeps mucus upwards. ASL must be the height of the cilia

Question 30

What is the genetic cause of cystic fibrosis

Answer 30

-Deletion mutation in CFTR protein causing frameshift
-Protein can not fold, should be a protein channel but sometimes does not make it out of ER to function in cell membrane

Question 31

What is the cystic fibrosis transmembrane conductance regulator protein

Answer 31

-Channel protein
-Moves chloride ions across epithelial membranes into ASL and regulates Na ions brought into cell
-Creates balanced ASL liquid height
-If built incorrectly, ER holds it back