BLOCK B

Question 1

WHAT IS A METAZOAN

Answer 1

TWO TYPES OF EUKARYOTIC ORGANISMS
-PROTISTS=SIMPLEST, SINGLE CELL EUKARYOTES, BUT STILL CARRY OUT LIFE FUNCTIONS AND SHOW DIVISION LABOUR AMONG THE VARIOUS CELL STRUCTURES
-METAZOANS=MULTICELLULAR ANIMALS THAT HAVE CELLS SPECIALISED FOR PARTICULAR FUNCTIONS

Question 2

WHAT TYPE OF SYMMETRY HAS EVOLVED

Answer 2

RADIAL AND BILATERAL

Question 3

WHAT IS BILATERAL SYMMETRY ASSOCIATED WITH

Answer 3

CEPHALISATION, THE DIFFERENTIATION OF A HEAD:
-NERVOUS SYSTEM, SENSE ORGANS, AND OFTEN THE MOUTH ARE LOCATED IN THE HEAD
ADVANTAGES FOR ORGANISMS MOVING HEAD FIRST= DIRECTIONAL MOVEMENT
-ELONGATION ALONG ANTEROPOSTERIOR AXIS

Question 4

HOW MANY GERM LAYERS DO WE HAVE THAT CONTRIBUTE TO DIFFERENT TISSUES AND PARTS OF THE BODY

Answer 4

3

Question 5

WHAT IS THE INTERNAL LAYER

Answer 5

ENDODERM
-LUNG CELLS
-THYROID CELLS
-DIGESTIVE CELLS

Question 6

WHAT IS THE MIDDLE LAYER

Answer 6

MESODERM
-CARDIAC MUSCLE CELLS
-SKELETAL MUSCLE CELLS]
-TUBULE CELLS OF THE KIDNEY
-RED BLOOD CELLS
-SMOOTH MUSCLE CELLS

Question 7

WHAT IS THE EXTERNAL LAYER

Answer 7

ECTODERM
-SKIN CELLS OF EPIDERMIS
-NEURON ON BRAIN
-PIGMENT CELLS

Question 8

WHAT FEATURES ARE IMPORTANT FOR EVOLUTION OF BODY CAVITY

Answer 8

-ISOLATION OF ORGANS FOR PHYSIOLOGICAL INDEPENDENCE: KIDNEY FUNCTION DIFFERENT FROM LIVER
-FLEXIBILITY WHEN MOVING: ORGANS DONT RIP APART
-SEPARATE ORGANS CUSHIONED AGAINST DAMAGED BY FLUID-DILLED CAVITY
-PREVENTS ORGANS FROM STICKING TO EACH OTHER:CELLS LIKE TO INTERMINGLE

Question 9

WHAT ARE COELOMATES

Answer 9

HAVE BODY CAVITY ENTIRELY WITHIN THE MESODERM
CALLED COELOM

Question 10

HOW DO OUR BODIES FORM IN THE WAY THEY DO ?

Answer 10

THROUGH THE PROCESSES OF EMBRYONIC DEVELOPMENT

Question 11

WHAT DOES FERTILISATION RESTORE

Answer 11

DIPLOID GENOME
-IT ALSO BEGINS THE PROCESS OF WIPING OUT MEMORY OF OUR PARENTS

Question 12

WHAT IS CLEAVAGE

Answer 12

2-CELL,4-CELL8-CELL
-CLEAVAGE IS THE DIVISION OF CELLS IN THE EARLY EMBYRO
-UNDERGOES RAPID CELL DIVISIONS WITH NO SIGNIFICANT GROWTH
-PRODUCE A CLUSTER OF CELLS THE SAME SIZE AS THE ORIGINAL ‘ZYGOTE’

Question 13

WHAT IS THE BLASTOCYST

Answer 13

A STRUCTURE CONSISTING OF 128 CELLS
INNER CELL MASS=(EMBRYOBLAST) GOES ON TO FORM THE EMBYRO PROPER
OUTER CELL MASS= (TROPHOBLAST) THIS GOES ON TO FORM THE PLACENTA

Question 14

WHAT IS PLURIPOTENT CELLS

Answer 14

THEORETICALLY CAN GIVE RISE TO EVERY CELL TYPE IN THE ANIMAL BODY PROPER
-PROLIFERATE INDEFINITELY
-FIRST RECOGNIE IN TERATOCARCINOMAS (FORM OF CANCER)
-THINKING IT IS DEVELOPING CELLS

Question 15

WHAT IS IMPLANTATION

Answer 15

-PROVIDES DIRECTION
-THE BLASTOCYST ‘HATCHES’ BY SHEDDING POUTER LAYER
-HATCHING EXPOSES THE BARE TROPHOBLAST CELLS TO THE UTERINE WALL (DAY 7)
-THE UTERINE WALL IS PREPARED FOR IMPLANTATION EACH MONTH UNDER HORMONAL CONTROL
-THE TROPHOBLAST BEGINS TO THICKEN AS IT BEGINS TO IMPLANT AND FORM PLACENTA
EMBRYO IS FULLY EMBEDDED AFTER 10 DAYS

Question 16

WHERE IS AMNIOTIC CAVITY FORMED

Answer 16

INNER CELL MASS PULLS AWAY FROM THE TROPHOBLAST FORMING A HOLLOW AMNIOTIC CAVITY

Question 17

WHAT ARE THE TWO CELL LAYERS

Answer 17

EPIBLAST=DORSAL,NEXT TO AMNIOTIC CAVITY
HYPOBLAST=VENTRAL, FACING YOLK SAC

Question 18

WHAT DOES THE ICM FORM

Answer 18

A FLAT DISC WITH TWO LAYERS

Question 19

WHAT HAPPENS ON DAY 9

Answer 19

AMNIOTIC CAVITY
EPIBLAST (GREY AREA)
HYPOBLAST (PURPLE AREA AFTER YELLOW)
ANATOMICAL DIRECTIONS DEFINED AND SYMMETRY BROKEN

Question 20

WHAT IS GASTRULATION MOVEMENT

Answer 20

-SOME EPIBLAST (ECTODERM) CELLS BEGIN TO MIGRATE INWARDS TOWARDS THE PRIMITIVE STREAK
-THEN THEY MOVE THROUGH THE LAYER TOWARDS THE HYPOBLAST (PRIMITIVE ENDODERM) THE FIRST CELLS THROUGH BECOME THE DEFINITIVE ENDODERM
-THE NEXT CELLS THROUGH FORM AN INTERMEDIATE LAYER CALLED MESODERM
-MOVEMENT PROGRESSES TAIL TO HEAD (CAUDAL TO CRANIAL)

Question 21

WHAT ARE THE THREE GERM TISSUES

Answer 21

ECTODERM AND ENDODERM ARE EPITHELIAL TISSUE (FORMS SHEETS FROM TISSUE_
MESODERM IS A MESENCHYMAL TISSUE (STAR SHAPED AND DO NOT ATTACH TO ONE ANOTHER, MIGRATE FREELY)

Question 22

WHAT DOES EPIBLAST MIGRATE THROUGH

Answer 22

PRIMITIVE PIT FORMING A LINE TOWARDS THE HEAD

Question 23

WHAT IS NOTOCHORD MATURATION

Answer 23

IT IS A ROD DEFINING THE BOYD AXIS AND IS THE FUTURE SIZE ODF THE VERBAL COLUMN

Question 24

WHAT IS NEURULATION

Answer 24

-HOW THE BRAIN AND SPINE FORM
-THE NOTOCHORD INDUCES A FOLD IN THE OVERLYING EPIBLAST/ECTODERM
-PINCHES OFF TO FORM A NEURAL TUBE

Question 25

WHAT DOES NOTOCHORD SIGNALLING DO

Answer 25

-CONVERTS THE OVERLYING ECTODERM -TO BECOME NEURAL PLATE -NEURAL PLATE TO NEURAL GROOVE TO NEURAL TUBE:PINCHED OFF INTO BODY -NEURAL GROOVE FORMATION -ASSOCIATED NEURAL CREST CELLS -MESODERM BEGINS TO DIFFERENTIATE NEXT TO NOTOCHORD THREE REGIONS -CLOSURE OF NEURAL TUBE:BEGINS AT END OF WEEK 3: COMPLETE BY END OF WEEK 4 -ZIPPED CRANIALLY (EVENTUALLY BRAIN) AND CAUDALLY (EVENTUALLY SPINE) -NEURAL CREST CELLS FORM SENSRY NERVE CELLS AND OTHER STRUCTURES

Question 26

WHAT IS SPINABIFIDA

Answer 26

-CONDITION CAUSED BY INCOMPLETE NEURAL TUBE CLOSURE -MOST EFFECTIVE WAY TO PREVENT SPINA BFIDA IS TO TAKE FOLLIC ACID/FOLATE SUPPLEMENTS BEFORE AND DURING PREGNANCY

Question 27

WHAT IS CELL DIFFERENTIATION

Answer 27

-CELLS IN ISOLATION -STARTED AS PLURIPOTENT STEM CELLS IN THE BLASTOCYST BUT OVER TIME BECAME MORE SPECIALISED UNTIL THEY REACH THEIR TERMINALLY DIFFERENTIATED FORM: HEART MUSCLE, NEURON, LIVER CELL -THERE IS PROGRAMMED PATHWAYS TO SPECIFIED FORM/FATE=ONE WAY ROAD

Question 28

CELL DIFFERENTIATION EARLY DEVELOPMENT

Answer 28

1.EACH SINGLE CELL HAS ALL THE INFO AND ABILITY TO BECOME THE ADULT ORGANISM 2.TRANSPLANTED CELLS ADOPT FORM APPROPRIATE FOR THEIR NEW HOME 3.CELLS TAKEN FROM DIFFERENT PARTS OF EMBRYO REMEMBER WHERE THEY CAME FORM AND DIFFERENTIATE ACCORDINGLY: THEY HAVE ALREADY BECOME 'SPECIFIED'

Question 29

WHAT SHOULD BE OCCURRING IN CELL

Answer 29

-LOCAL CELLULAR INTERACTIONS THAT ORGANISE TISSUES -LONG-RANGE SIGNALS THAT DETERMINE THE ORIENTATION OF THE EMBRYO AND ITS SPECIFIC REGIONS -CELLULAR RESPONSE TO THESE TWO TYPES OF SIGNALS THAT CAUSE MIGRATION AND SPECIFIC DIFFERENTIATION PROCESSES TO BE IRREVERSIBLY STARTED

Question 30

WHAT IS CELL INTERACTIONS

Answer 30

-CAN ORGANISE THEMSELVES LOCALLY 1.MIXTURES OF DIFFERENT CELL TYPES ORGANISE INTO REGIONAL EMBRYO-LIKE STRUCTURE SORTING OF CELLS LIKE-WITH-LIKE CELL ADHESION=OFTEN DRIVES THIS:PROTEINS EXPRESSED ON THE SURFACE OF CELLS THAT LIKE TO STICK TO THE SAME MOLECULES ON OTHER CELLS: HOMOPHILIC INTERACTIONS

Question 31

WHAT IS THE MORPHOGEN GRADIENTS

Answer 31

-MORPHOGEN IS SECRETED MOLECULE THAT INDUCES CELL FATE DECISIONS IN RECIPIENT CELLS IN A CONCENTRATION GRADIENT-DEPENDENT LONG-RANGE MANNER

Question 32

WHAT IS REQUIRED FOR MORPHOGEN GRADIENT

Answer 32

-PRODUCTION FROM A POINT SOURCE -LONG-RANGE DISTRIBUTION -RECEPTION AND INTERPRETATION BY CELL -INTERPRETATION IS CONTEXT-DEPENDENT

Question 33

WHAT ARE NODAL AND LEFTY

Answer 33

TWO GENES THAT SHOW UNEQUAL EXPRESSION BETWEEN THE LEFT AND RIGHT SIDES OF THE EMBRYO

Question 34

WHAT DO MORPHOGEN RECEPTORS DO

Answer 34

SIGNAL TO THE NUCLEUS TO INITIATE APPROPRIATE DIFFERENTIATION PROGRAMS WITHIN THE CELL

Question 35

WHAT ARE HOMEOTIC GENES

Answer 35

-MUTATION, THAT CAUSES TRANSFORMATION OF AN AREA OF THE BODY INTO ANOTHER AREA

Question 36

WHAT HAPPENS BY THE END OF THE 2ND TRIMESTER

Answer 36

HUMAN DEVELOPMENT IS COMPLETE

Question 37

WHAT HAPPENS BY THE END OF THE 1ST TRIMESTER

Answer 37

EARLY CELL DIVISIONS, ESTABLISHMENT OF GERM LAYERS, BEGINNING OF ORGANOGENESIS

Question 38

WHAT ALSO HAPPENS IN 2ND TRIMESTER

Answer 38

ORGANOGEMNESIS COMPLETE

Question 39

WHAT HAPPENS IN 3RD TRIMESTER

Answer 39

FEATAL GROWTH, ORGAN SYSTEMS FUNCTIONAL

Question 40

WHAT IS SRY

Answer 40

GENE ON THE Y CHROMOSOME THAT CONTROLS MALE CHARACTERISTICS -PROMOTES DEVELOPEMNT OF MALE REPRODUCTIVE ANATOMY -SUPPRESSES DEVELOPMENT OF FEMALE REPRODUCTIVE ANATOMY