Human Development and Cancer (16,17,18,19,20,21) Flashcards
What is involved in cell division?
a. Cells maintain their size during cleavage due to the G1 and G2 phases
b. An original cell divides into many cells and each daughter cell receives a full copy of the genome
c. Cleavage does not occur until after differentiation and determination
d. The embryo remains the same size during later cell divisions due to the absence of the G1 and G2 phase
b. An original cell divides into many cells and each daughter cell receives a full copy of the genome
What does not occur during differentiation?
a. All genes are expressed to the same degree in all cells
b. Internal structure and outward appearance of cells is established
c. Cells can become polarised
d. Differential gene expression occurs
a. All genes are expressed to the same degree in all cells
How do drosophila neural stem cells divide?
a. GMCs divide into daughter neuroblasts
b. Symmetric division due to secretion of wingless
c. Asymmetric division due to the localisation of prospero
d. By inhibiting the BMP signalling pathway
c. Asymmetric division due to the localisation of prospero
Which is not a common signalling pathway?
a. TGFB/BMP
b. Hedgehog
c. FGF (MapK)
d. Hippo/Yorkie
d. Hippo/Yorkie
What is involved in morphogenesis?
a. Apoptosis is not a normal part of morphogenesis
b. Cells develop through cell divisions due to cleavage and growth
c. Once morphogenesis begins, cells cannot migrate
d. Morphogenesis only involves MET
b. Cells develop through cell divisions due to cleavage and growth
What is not an example of collective cell behaviour?
a. Epithelial folding
b. Convergent extension
c. Cleavage and Growth
d. Epithelial branching
c. Cleavage and Growth
What does twist do?
a. It is a determinant in the neuroblasts of drosophila during asymmetric division
b. It regulates genes for epithelial folding, EMT and migration
c. It causes MET of cells in the drosophila embryo
d. It is expressed in the dorsal side of human embryos to regulate many genes at once
b. It regulates genes for epithelial folding, EMT and migration
What is not a benefit of drosophila as a model organism?
a. It has a large genome like humans
b. Cultivation is short and easy
c. The embryo is easy to visualise
d. Ready access to genetic resources
a. It has a large genome like humans
What accurately describes a benefit of a specific model organism?
a. Flies can be frozen and kept alive to be studied at a later date
b. Worms can be genetically manipulated via mRNA injections to the zygote (Frog)
c. The cell linage of chicks has been determined
d. Zebrafish have a clear embryo and are genetically tractable vertebrates
d. Zebrafish have a clear embryo and are genetically tractable vertebrates
• To form the blastocyst, the morula must escape the zona pellucida in order to contact the uterus epithelium.
T
• Cell division of B and T lymphocytes and sperm cells results in daughter cells receiving a full copy of the genome.
F
• Cells in the presumptive eye region in drosophila are determined at the gastrula stage.
F neurala)
• In propspero mutants, GMCs are transformed into self-renewing neural stem cells.
T
• There is no G1 and G2 stage during cleavage.
T
• EMT involves the formation of a polarise epithelium and MET involves the formation of migratory cells.
F
• Most cases of achondraplasia result from a glycine to arginine mutation in the FGFR3 gene.
T
• Cancer can develop when regulatory genes are mutated and cells escape the strict controls of development.
T
What correctly describes the events from ovulation to implantation?
a. The morula forms in the ovary
b. First cleavage occurs in the uterus
c. Fertilisation occurs in the fallopian tube
d. The blastocyst develops in the ovary
c. Fertilisation occurs in the fallopian tube
What occurs during fertilisation?
a. When a spermatozoa contacts the zona pellucida, the egg release proteolytic enzymes to break down the zona pellucida. (sperm does)
b. A spermatozoa contacts the oocyte after the second meiotic division and creation of the 2nd polar body and female pronucleus
c. Once the sperm pronucleus is delivered into the oocyte, the egg releases enzymes that modify the surface and prevent more sperm from entering
d. The male and female pronuclei fuse to form the first haploid cell known as the zygote
c. Once the sperm pronucleus is delivered into the oocyte, the egg releases enzymes that modify the surface and prevent more sperm from entering
What is a feature of the morula?
a. It describes the embryo at the 8 cell stage
b. It develops following cleavage and rapid G1 and G2 cycles
c. It describes the embryo at the 16 cell stage
d. It develops following cleavage of the blastocyst
a. It describes the embryo at the 8 cell stage
Epithelial cells:
a. Are polarised along the dorsal-ventral axis
b. Are detached from neighbour cells
c. Have tight junctions to prevent molecules and water passing between them
d. Have gap junctions for adhesion
c. Have tight junctions to prevent molecules and water passing between them
What happens during compaction?
a. E-cadherin is down-regulated in cells
b. The first epithelium is formed
c. Cells lose polarity in order to maximise contact
d. Microvilli can be restricted to the basal surface
b. The first epithelium is formed
How does the inner cell mass form?
a. Through symmetric divisions within the morula
b. During cleavage and compaction of the blastocyst
c. From the unpolarised inner cell that results from asymmetric division in the morula
d. When E-cadherin expression is turned off in the morula
c. From the unpolarised inner cell that results from asymmetric division in the morula
How do the first major cell linages split?
a. Outer cells in the morula express Oct4
b. Oct4 and Cdx2 mutually activate one another
c. Inner cells in the moruala express Cdx2
d. Mutual repression of Cdx2 and Oct4 stabilises cell differentiation
d. Mutual repression of Cdx2 and Oct4 stabilises cell differentiation
How do the epiblast and hypoblast develop?
a. Epiblast cells express nanog which represses GATA6
b. Hypoblast cells lack GATA6 expression
c. FGF4 directly activates nanog expression in epiblast cells
d. Hypoblast cells express nanog in order to up-regulate GATA6
a. Epiblast cells express nanog which represses GATA6
What is not a feature of gastrulation?
a. It is the first event of morphogenesis and involves body axes being defined
b. The Primitive streak forms in a region where epiblast cells undergo EMT and enter the space between epiblast and hypoblast layers
c. Cells exit the primitive streak and intercalate in outer hypoblast layer to form endoderm
d. The endoderm only contains epiblast cells
d. The endoderm only contains epiblast cells
What is a feature of the germ layers?
a. Epiblast cells coming through the primitive streak take on a mesodermal fate
b. The mesoderm can give rise to the gut and lungs
c. Endoderm forms from epiblast cells that don’t go through the primitive streak (ectoderm)
d. Ectoderm gives rise to muscle and connective tissue
a. Epiblast cells coming through the primitive streak take on a mesodermal fate
What occurs during mesodermal cell migration?
a. Ecad is up regulated to encourage a MET transition
b. FGF4, FGF8 are expressed in the primitive streak
c. FGFR1 interactions lead to Ecad expression via Snail
d. FGFR1 mutants demonstrate repressed Ecad expression
b. FGF4, FGF8 are expressed in the primitive streak
What occurs through the FGF pathway?
a. It leads to Brachyury expression in mesodermal cells
b. It signals for sperm to release proteolytic enzymes upon contact with the zona pellucida
c. Snail is repressed so that Ecad can be expressed
d. It represses Brachyury which is a regulator of endodermal cell fate
a. It leads to Brachyury expression in mesodermal cells
• Ecadherin (epithelial cadherin) is the major cell-cell adhesion molecules in adherens junctions.
T
• Cancer metastasis can result when epithelial cell polarity factors are lost.
T
• During blastocyst formation, the blastocyst appears to pulse as water is pumped out of the morula.
F
• The zona pellucida must be intact for the blastocyst to make contact with the uterine wall epithelium.
F
• Embryonic stem cells are derived from the hypoblast of the inner cell mass.
F
• The amniotic cavity forms within epiblast cells and the primitive yolk sac forms within hypoblast cells.
T
• During gastrulation, the ectoderm is the first germ layer to form.
F (endoderm)
What defines the body axes and determines the body plan?
a. The neural tube
b. Epidermis/Mesoderm junctions
c. The primitive streak
d. Presomitic mesoderm
c. The primitive streak
What occurs in neurulation?
a. The neural tube forms the neural plate
b. Epithelial folding of the neural plate leads to the formation of the neural tube
c. A region of mesoderm thickens to form the neural plate
d. The neural tube results from convergent extension
b. Epithelial folding of the neural plate leads to the formation of the neural tube
What is a feature of neural tube defects?
a. An open anterior neuropore results in spina bifida
b. They affect 1 in 100 pregancies (1 in 1000)
c. An open posterior neuropore results in ancephaly
d. They can involve mutations in genes in the PCP pathway
d. They can involve mutations in genes in the PCP pathway
What is not a pathway associated with neural tube defects?
a. Wnt/B-catenin pathway
b. PCP pathway
c. Hedgehog pathway
d. TGFB/BMP pathway
a. Wnt/B-catenin pathway
What is not a feature of neural crest cells?
a. They undergo SLUG dependent EMT
b. They arise from the region between the neural plate and epidermis
c. They form epithelial cells which insulate the spinal cord
d. They are called the “fourth germ layer” due to their ability to differentiate to many cell types
c. They form epithelial cells which insulate the spinal cord
What is false about Waardenburg Syndrome?
a. The phenotype is hypo-pigmentation and deafness
b. Mutations to the MITF gene are dominant negative
c. The mutation can be mapped to the long arm of chromosome 3 or 13
d. The white forelock arises due to a failure in melanocyte migration
c. The mutation can be mapped to the long arm of chromosome 3 or 13