exam 1 prs Flashcards
The embryonic stage of cleavage is characterized by: Rapid mitotic divisions Embryonic growth Sperm and egg fusion Cellular rearrangements
A.
What embryonic stage results in the three germ layers? Fertilization Cleavage Gastrulation Organogenesis
C
The Ectoderm, or outer layer, of the embryo gives rise to: Blood Bone Kidneys Brain
D
Epithelial cells are \_\_ while mesenchymal cells are \_\_. Mesoderm, endoderm Dividing, growing Tightly connected, unconnected Unconnected, tightly connected
C
six basic events of embryogenesis
Fertilization- egg and sperm meet to form zygote
Cleavage- fast divisions, no growth
Gastrulation- folding of tissue, formation of germ layers
Organogenesis- creation of organs from germ layers
Metamorphosis-period of growth and development after hatching
Gametogenesis- formation and maturation of germ cells
On your own: In general, histone methylation ______ gene expression and DNA methylation _______ gene expression.
activates or represses
represses
What protein binds to the promoter but not to the enhancer? RNA Polymerase II DNA Polymerase I Pax6 Crystallin
RNA Polymerase II
\_\_\_\_\_\_\_\_ methylation can be inherited through genomic imprinting. DNA Histone Pax2 Crystallin
DNA
A single base-pair change in an enhancer of the lactase gene is likely responsible for lactose tolerance. Which of the following does this mutation likely affect? Binding of_______.
- RNA Polymerase II
- Mediator
- Tissue-specific Transcription factor
- TFIID
- TATA Binding Protein
c
The molecules involved in (alternative) splicing do NOT include U1 sRNA U2AF SF2 Maskin
d
RNAs for which of the following molecules is NOT likely to be stored in an unfertilized amphibian oocyte? Tubulin Cyclin Myostatin Actin Histone H2A
c
Which of the following is NOT a mechanism used by miRNAs to control mRNA translation? Blocking initiation factors Cleaving mRNA Unwinding miRNA Recruiting endonuclease
c
Which of the following is NOT a mechanism of cytoplasmic mRNA localization?
- Active transport along cytoskeleton
- Localized protection
- Initiation block
- Diffusion and local anchoring
c
The protein Dicer performs which of the following functions during miRNA processing?
- Exporting miRNA from cytoplasm
- Unwinding the hairpin loop
- Assembling the RISC
- Generating single-stranded miRNAs from the pre-miRNA hairpin loop
b,c,d
An in situ hybridization (ISH) uses a labelled _____ molecule as a probe to locate _______ expression in an embryo.
RNA, RNA
Holtfreter dissociated then mixed different tissue types together and observed different aggregation patterns. Which of the following is NOT a conclusion based on his findings?
- Re-aggregated cells became spatially segregated
- The final positions reflect embryonic positions
- Different tissues bind with different affinities
- Affinities remain the same over the course of development
d
Which of the following does NOT describe a property associated with cadherin molecules?
- They are a transmembrane molecule
- Sodium ions play a role in cadherin-cadherin binding
- Adhesion strength is related to the quantity of cadherin molecules
- Not all cadherin sub-types can bind each other
B
Which of the following describes permissive induction?
- Alters gene expression in the responding cell.
- Without the inducing cell, the responding cell is not capable of differentiating (in that particular way)
- The tissue is already specified
- The tissue is not already specified
a and c
When foot dermal mesenchyme of a chicken is transplanted to wing epidermal epithelium, it causes the overlying epithelium to generate scales. Is this an example of permissive or instructive induction?
instructive
During kidney development, the ureteric bud induces nephrogenic mesenchyme to become mesonephric tubules. Mesenchyme needs a signal to grow, but can’t become anything except kidney tissue. Is this instructive or permissive induction?
permissive
Mouse mammary gland tissue begins to express proteins specific to mammary gland tissue upon contact with basal lamina in culture. Is this an example of permissive or instructive induction?
permissive
When non-optic vesicle tissue is transplanted below the head ectoderm, or when the optic vesicle is removed, no lens forms. Is this an example of permissive or instructive induction?
instructive
What would the basic RTK pathway look like when FGFR3 is constitutively active?
- High levels of phosphorylated Ras, Transcriptionally active
- High levels of phosphorylated Ras, Not transcriptionally active.
- Low levels of phosphorylated Ras, Transcriptionally active
- Low levels of phosphorylated Ras, Not transcriptionally active
a
Which of the following is NOT a component of the extracellular matrix?
Laminin
Fibronectin
proteoglycans
Phospho-ERK
d
