YEAST SCREENS

Question 1

EUKARYOTIC CELLS NEED MEMBRANE TRAFFICKING BECAUSE A FEATURE OF EUKARYOTES IS …………………………

Answer 1

COMPARTMENTALISATION

Question 2

COMPARTMENTALISATION ALLOWS MORE ………………………….

Answer 2

COMPLEXITY

Question 3

CERTAIN ENZYMES REQUIRE CERTAIN …………………….. TO FUNCTION IN SUCH AS …………

Answer 3

ENVIRONMENTS

PH

Question 4

WHAT ARE THE MAJOR FEATURES OF TRAFFICKING PATHWAYS

Answer 4

1. PROTEIN SYNTHESIS ON BOUND RIBOSOMES - COTRANSLATIONAL TRANSPORT OF PROTEINS INTO/ACROSS ER MEMBRANE
2. BUDDING/FUSION OF ER - GOLGI VESICLES FORM CIS GOLGI
3. CISTERNAL PROGRESSION OR RETROGRADE GOLGI TO ER TRANSPORT
4. RETROGRADE FROM LATER TO EARLIER GOLGI CISTERNAE
5. CONSTITUITIVE SECRETION
6. REGULATED SECRETION
7. SORTING TO LYSOSOMES
8. ENDOCYTOSIS

Question 5

MODEL SYSTEMS FOR MEMBRANE TRAFFICKING REQUIRE WHAT

Answer 5

SIMPLE CELLULAR SYSTEM

A SYSTEM THAT HAS THE FUNCTION BEING STUDIED.

Question 6

WHAT ARE THE ADVANTAGES OF YEAST AS A MODEL

Answer 6

ENTIRE GENOME KNOWN
CAN GROW AS HAPLOID/DIPLOID
CHEAP AND EASY TO GROW IN LARGE AMOUNTS
LIMITED GENE DIVERSITY
FUNDAMENTAL PATHWAYS CONSERVED

Question 7

WHAT ARE THE DISADVANTAGES OF YEAST AS A MODEL

Answer 7

LIMITED CELL-CELL CONTACT THEREFORE CANNOT STUDY MULTICELLULARITY
SMALL SO MICROSCOPY DIFFICULT
CELL WALL WHICH CAN MAKE SOME STUDIES DIFFICULT

Question 8

WHO IDENTIFIED THE GENES OF THE SECRETORY PATHWAY

Answer 8

NOVICK AND SCHEKMAN 1980

Question 9

WHAT WAS THE RATIONALE BEHIND THE INDENTIFICATION OF GENES IN THE SECRETORY PATHWAY

Answer 9

IF CELLS ARE SECRETORY DEFICIENT THEN THE CELL WOULD INCREASE IN DENSITY AS THE VESICLES CARRYING THE PROTEINS ACCUMULATE

Question 10

WHAT ARE DEFINED SECRETORY MUTANTS

Answer 10

THOSE THAT FAIL TO EXPORT ACTIVE INVERTASE AND ACID PHOSPHATASE BUT CONTINUE TO SUNTHESISE PROTEIN

Question 11

HOW MANY GENES WERE IDENTIFIED BY GROUPING MUTANTS BY PHENOTYPE IN MUTANT SECRETORY PROTEINS

Answer 11

23

Question 12

ALPHA FACTOR IS GLYCOSYLATED AND …………………………….. CLEAVED AT DIFFERENT STAGES IN THE SECRETORY PATHWAY. BY FOLLOWING ITS PROCESS WE CAN LOCATE THE POSITION OF THE ……………………
THE SIZE OF THE PROTEIN (SHOW BY ………………………. BLOT) CAN SHOW WHICH STAGE OF ………………………….. ALPHA FACTOR GO TO.

Answer 12

PROTEOLYTICALLY
MUTATION
WESTERN
MODIFICATION

Question 13

WHERE IS THE DECISION MADE AS TO WHETHER SOMETHING IS TRAFFICKED TO THE MEMBRANE OR TO A LYSOSOME

Answer 13

THE TRANS GOLGI NETWORK

Question 14

HOW MANY CLASSES DO THE 23 MUTANT GENES IN THE SECRETORY PART OF THE PATHWAY FALL INTO

Answer 14

5

Question 15

WHAT ARE THE CLASSES OF SEC MUTANTS

Answer 15

CLASS A: ACCUMULATION IN CYTOSOL
CLASS B: ACCUMULATION IN RER
CLASS C: ACCUMULATION IN ER TO GOLGI VESICLES
CLASS D: ACCUMULATION IN GOLGI
CLASS E: ACCUMULATION IN SECRETORY VESICLES

Question 16

IN THE NOVICK SCHEKMAN EXPERIEMENTS WHAT ARE THE REASONS NOT EVERYTHING WAS IDENTIFIED

Answer 16

ONLY IDENTIFIED TEMPERATURE SENSITIVE MUTANTS
ONLY CONSIDERED THE SECRETORY PATHWAYS TO THE MEMBRANE SO DEFECTS IN ENDOSOME/VACUOLE WOULD NOT BE IDENTIFIED
REDUNDANT FUNCTIONING GENES (OVERLAP) WOULD NOT BE IDENTIFIED

Question 17

WHAT ARE THE TYPES OF SCREENING THAT CAN BE DONE IN MEMBRANE TRAFFICKING

Answer 17

SEC SCREENS
END SCREENS
VPS SCREENS

Question 18

WHAT IS ENDOCYTOSIS

Answer 18

PLASMA MEMBRANES INVAGINATE RESULTING IN A VESICLE THAT CAN FUSE WITH ENDOSOMES

Question 19

WHAT IS THE IMPORTANCE OF ENDOCYTOSIS

Answer 19

RETRIEVAL OF MOLECULES FOR RECYCLING
DOWN REGULATION OF SIGNALS
REMODELLING OF CELL SURFACE COMPOSITION
MEANS OF ENTRY BY TOXINS/PATHOGENS

Question 20

WHAT IS THE NAME OF ENDOCYTOTIC MUTANTS IN THE TRAFFICKING PATHWAY

Answer 20

END-

Question 21

HOW DO YOU DETECT END - MUTANTS

Answer 21

CANNOT INTERNALISE A FLUID PHASE MARKER SUCH AS LUCIFER YELLOW
IN WILD TYPE, WOULD LIGHT UP IN THE MIDDLE

Question 22

HOW MANY GENES HAVE BEEN DETECTED AS END - MUTANTS

Answer 22

7

Question 23

OF THE SEVEN END - MUTANTS, HOW MANY ARE DIRECTLY INVOLVED IN MEMBRANE INVAGINATION AND SCISSION

Answer 23

5

Question 24

WHAT IS THE FUNCTION OF A LYSOSOME

Answer 24

DEGRADES EC MATERIAL TAKEN UP BY ENDOCYTOSIS AS WELL AS SOME IC COMPONENTS

Question 25

WHY DO LYSOSOMES EXIST

Answer 25

ENZYMES MUST BE CONTAINED WITHIN THEIR OWN COMPARTMENT

Question 26

CARBOXYPEPTIDASE Y IS NORMALLY TRANSPORTED FROM .................... TO LYSOSOME. GENERATION OF MUTAGENISED CELLS AND MICROSCOPY IDENTIFIED OVER .............. VPS GENES. MANY OF THESE GENES WORK IN ........................ LIKE ALPHA FACTOR, CPY IS ........................ AND CLEAVED AND THIS CAN HELP IDENTIFY WHERE THE DEFECT HAS OCCURED.

Answer 26

GOLGI 60 COMPLEXES GLYCOSYLATED

Question 27

VACUOLAR MUTATANT ARE DIVIDED INTO CLASSES DEPENDING ON THE STAGE OF BLOCKAGE. WHAT ARE THESE

Answer 27

1. EARLY GOLGI 2. LATE GOLGI 3. EARLY ENDOSOME 4. LATE ENDOSOME 5. MVB 6. LYSOSOME

Question 28

AT WHICH STAGE DO VACUOLAR MUTANTS OCCUR MOST

Answer 28

BETWEEN LATE ENDOSOME AND MVB

Question 29

MOLECULAR DETERMINANTS TELL US WHERE THE PROTEIN NEEDS TO GO. FROM THE TGN THERE ARE FOUR POSSIBLE DESTINATIONS. WHAT ARE THEY

Answer 29

PLASMA MEMBRANE EARLY ENDOSOME LATE ENDOSOME/MVB VACUOLE

Question 30

HOW DO PROTEINS GET TO WHERE THEY NEED TO GO

Answer 30

IF THERE IS NO OR A DISRUPTED SIGNAL THEN CONTENTS WILL BE TRAFFICKED TO THE MEMBRANE

Question 31

WHAT IS THE CPY TRAFFICKING PATHWAY

Answer 31

CPY RECOGNISED BY RECEPTOR VPS10 THIS COMPLEX RECOGNISED BY CLATHRIN, GGA1/2 THIS SIGNALS THAT THIS WILL BE GOING TO THE LATE ENDOSOME VPS10 DISSOCIATES FROM CPY AT THE LATE ENDOSOME VPS10 IS RETRIEVED TO THE LATE GOLGI BY YSSL CPY IS TRANSPORTED TO VACUOLES.