Developmental / Embryology

Question 1

Alveolar cells arise from
A endoderm
B mesoderm
C ectoderm
D ecto and endodrrm

Answer 1

Answer is endoderm
Why? Endoderm is epithelial lining of the respiratory system
Mesoderm does the cartilidge, smooth muscle and endothelium

Question 2

what happens in the Cortical reaction?

Answer 2

Exocytosis of cortical granules to release digestive enzymes on Zona pellucida preventing more sperm from binding
> hardens ZP, removed the ZP3 which has the recognition membrane

Question 3

Gastrualation

Answer 3

movement of germ layers relative to one another e.g. forming animal and vegetal poles, and patterning

Question 4

What does the acrosome of sperm contain?.... 
A lysozymes
B hyaluronidase
C proteases
D abscasic acid

Answer 4

B
Contact with the zona pellucida triggers acrosomal reaction (release of enzymes via calcium mediated exocytosis)
> GALT recognises NAG on ZonaP3

Question 5

What is the correct order for animal development stages?
A fertilisation, gastrulation, cleavage, neurulation, organogeneis

B fertilisation, cleavage, gastrulation, neurulation, organogeneis

C fertilisation, cleavage, neurulation, organogeneis, gastrulation

D fertilisation, cleavage, neurulation, gastrulation, organogeneis

Answer 5

Fcgno
Option B
Cleavege from blastula,

Question 6

Role of cytoplasmic determinants
A prevent additional implantation of egg
B produce polar and nonpolar daughter cells
C determine the components of embryonic cell cytoplasm
D influence gene expression therefore affect the developmental fate of cell

Answer 6

D
Helps to make daughter cells different to each other, crucial for development
E. G. Emergence of pattern, morphogenesis, growth and potency

Question 7

What potency is a zygote
A pluripotent 
B totipotent
C unipotent
D oligopotent

Answer 7

B

Can make the extra embryonic tissues (placenta)

Question 8

What type of molecule is GSK-3 binding protein?
A transcription factor 
B TGFbeta signalling factor 
C kinase inhibitor
D homeobox gene

Answer 8

C
It inhibits protein kinase GSK-3 which allows beta-catenin to be stabilised in dorsal cells (as part of Wnt signalling)
> beta catenin can activate target gene expression
> GSK3b KINASE degrades beta catinin unless inhibited!

Question 9

In spematogensis, what stage of the cell cycle are primordial germ cells arrested /frozen in?

Answer 9

G1
after birth, diploid spematoGOnia mitosis to spematoCYTES and meiosis to TIDS
and then differentiate to mature ZOA/sperm
> meosis before differentiation

Question 10

In oogenesis, what stage of the cell cycle are primordial germ cells arrested /frozen in?
A G2
B mitosis anaphase
C meiosis prophase 1
D meoisis anaphase 1
E meosis metaphase 2

Answer 10

Prophase of meiosis 1 as primary oocytes
as adult they get larger and mature and in ovulation completed meosis 1!
> secondary oocyte frozen in metaphase 2 and in fertilisation meosis 2 is completed!

Question 11

the nervous system arises from which germ layer?

Answer 11

the ectoderm layer! (so does the skin)

Question 12

what is meant by ‘‘growth by accretion’’?

Answer 12

this means bone or shell is growing as the embryo grows. other ways of developmental growth are
> cell proliferation
> cell enlargement

Question 13

what would hapen if the embryo (with apical surfaces) undegoes tangential divison?

Answer 13

the daughter cells would be differet. one polarised and one not

Question 14

embryo name changes

Answer 14

blastomere(8 cells) to morula (3 days) to a blastocyst with a fluid filled cavity (blastocoel)

Question 15

sperm name changes

Answer 15

spermatoagonia
spermatocyte
spermatotid
spermatazoa ( mature sperm)

Question 16

egg name changes

Answer 16

oogonia / primordial oocyte??…
primary oocyte
secondary oocyte
ovum/egg + 2 polar bodues

Question 17

what does the trophectoderm and inner cell mass create?

Answer 17

T = extra embryonic tissue
ICM = embryo proper/ main body == embryoblast

Question 18

What is importance of calcium in cortical reactiob

Answer 18

Degrades cyclin - - > Metaphase 2 lifted in secondary oocyte in ovulation
this allows meosis of oocyte complete!!
> essential for intitiating embryo developement

Question 19

what triggers the cortical reaction?

Answer 19

the (2nd) recognition event of transmembrane proteins
Izumo + Juno transmembrane proteins that recruits oocyte protein CD9 allowing membranes to fuse
>sperm entry triggers the calcium ossilations release –> exocytosis of cortical granule

Question 20

what is the first fluid filled cavity to form during embryoinci delevopemnt
A amniotic cavity
B blastomere
C archenteron
D blastocoel
E epiblast

Answer 20

OPTION D

blastomere is a single cell

the primary gut that forms during gastrulation in the developing zygote is known as the archenteron/ digestive tube. It develops into the endoderm and mesoderm of an animal

Question 21

the muscle is from which germ layer?

Answer 21

the Mesoderm

> m for muscle haaha

Question 22

what does the inner cell mass split into?

Answer 22

epiblast - embryo proper/3 germ layers

hypoblast - furthur extraembryonic structures

Question 23

What does the endoderm develop into in vertebrates
A Gut, lungs and liver
B Muscles, blood and hearth
C Nervous system and epidermis
A Skeleton and kidney

Answer 23

OPTION A

The endoderm develops into the gut, lungs and liver in vertebrates, and just the gut in insects.

Question 24

Which of these statements is incorrect in fertilisation?
A Hyaluronidase activity on sperms head allows it to penetrate the cumulus layer
B Change in membrane potential opens voltage gated calcium channels, increasing intracellular Ca2+, triggering the acrosome reaction
C Sperm protein ‘Izumo’ recognises oocyte protein ‘juno’ recruiting CD9, causing the the plasma membranes to fuse
D Sodium release within the oocyte triggers completion of the second meiotic division and the cortical reaction
E Lytic enzymes from the cortical granules partially digest ZP2, and remove carbohydrate from ZP3, hardening the zone pellucid, preventing polyspermy

Answer 24

OPTION D

> calcium not sodium release (activates kinase that degrades cyclin lifting metaphase 2)

Question 25

The morula is formed from compaction of blastomeres. How many blastomeres from the morula?
6
7
8
9
10

Answer 25

8!

The morula is made of 8 compacted blastomeres.

Question 26

How long after fertilisation does the primitive streak form?
1 week

2 weeks

3 weeks

4 weeks

Answer 26

2 weeks
The primitive streak forms on the surface of the epiblast, 2 weeks after fertilisation.
this will be the posterior of embryo that epiblast cells wiill migrate towards leading to gastrualtion

Question 27

which proteins allow the embryo to stick and implant into the uterine wallq

Answer 27

lamin and fibronectin interacts with tropoblast integrin. occurs on DAY6 of fertilisation