HBIO 370 FINAL EXAM QUESTIONS AND ANSWERS WITH VERIFIED
SOLUTIONS 100%
2 stages of development
embryonic, post embryonic
embryonic development
from fertilization to 8 weeks post fertilization, major organ systems established from
3 primary germ layers, basic body plan emerges
Post embryonic development (fetal period)
weeks 9-38 (birth), organs grow in size and complexity, refinement of systems
5 processes of development
1. cell proliferation
2. cell growth
3. cell differentiation
4. pattern formation
5. morphogenesis
Cell proliferation
process of increasing cell numbers by mitotic divis
T/F: in mature organisms the cell number is not in equilibrium
False - cell number is maintained in dynamic equilibrium and maintained constant
thru apoptosis and proliferation/differentiation of progenitors
Development of our hands
apoptosis occurs in between our hand tissue, giving us our fingers
Cell growth
,Proliferating cells undergo cycles of cell division and growth (during which they
synthesize macromolecules and prepare for the next division)
In which stage of the cell cycle is folate important?
S - DNA synthesis bc folate needed to make 3/4 nucleotides
Hypertrophy vs hyperplasticity
hypertrophy = increase in cell size, these cells eat more
hyperplasia = increase in cell number
Cell Differentiation
progenitor cell receives stimuli from environment and responds by acquiring new
morphological, structural, and functional characteristics --> new cell identity
T/F: Cell differentiation is unidirectional
True - once a cell has differentiated it can't go back (very rare!)
Terminal differentiation
final stage of a cell in which it is highly specialized; can no longer divide and make
more cells
What is cell identity affected by?
transcription factors (clarify!)
What cell types are easier to transdifferentiate?
cells that are developmentally close such as hepatocytes to exocrine pancreas cells
are easier to differentiate
Pattern Formation
cells become organized into tissues, organs, and organ systems to give rise to
functional organism, initially form body plan and then develop detailed structures
Body plan symmetry
,Bilateral symmetry with respect to craniocaudal axis
Left-right axis defined by organs that are asymmetric
Morphogenesis
development of morphological characteristics - finger development, 4 chambers of
the heart
- differential cell prolif., selective cell-cell adhesion, changes in cell shape/size,
apoptosis involved in this
Milestones in Embryonic Development
2 weeks: initial divisions
Day 14: Gastrulation
Days 19-21: Neurulation
Days 21-24: Future head, neck, mouth, nose
Weeks 3-8: Beginning or organ formation
Week 8: Fetus formed
Gastrulation
3 distinct tissues begin to form, no more embryonic stem cells, occurs around day 14
Neurulation
beginning of future nervous system, formation of neural tube
Ovulation
ovum (egg) is released from ovary at day 14 of cycle
Fertilization
occurs in the fallopian tube - head of sperm fuses with oocyte membrane and its
pronucleus enters cytoplasm, pronuclei initially separated but then fuse to become
zygote and undergoes rapid cell division
Implantation
, zygote has become blastocyte, now arrives at the uterus and implants into uterine
lining
Morula
loosely packed ball of cells that forms a few days after fertilization, cells then start
differentiating
Compaction
cells transition from a loose arrangement to tightly packed arrangement, first
differentiation in mammalian development - involves separation of trophoblast from
inner cell mast, regulated by membrane polarization
- results in external polarized cells and internal non polarized cells
When does compaction occur
at 16 cell morula stage
External polarized cells
trophoblast (will give rise to the outer layer membrane and placenta) with tight
junctions to seal the inner cells off
Internal non polarized cells
inner cell mass (will give rise to the embryo) with gap junctions to exchange
substances
Cavitation
formation of blastocyte at 32 cell stage, involves formation of blastocoele and non
polarized cells form inner cell mass (ICM gives rise to the embryo)
Blastocoele
fluid filled cavity in blastocyst
When does the blastocyte implant to the uterine wall?
Day 6-7 of development
SOLUTIONS 100%
2 stages of development
embryonic, post embryonic
embryonic development
from fertilization to 8 weeks post fertilization, major organ systems established from
3 primary germ layers, basic body plan emerges
Post embryonic development (fetal period)
weeks 9-38 (birth), organs grow in size and complexity, refinement of systems
5 processes of development
1. cell proliferation
2. cell growth
3. cell differentiation
4. pattern formation
5. morphogenesis
Cell proliferation
process of increasing cell numbers by mitotic divis
T/F: in mature organisms the cell number is not in equilibrium
False - cell number is maintained in dynamic equilibrium and maintained constant
thru apoptosis and proliferation/differentiation of progenitors
Development of our hands
apoptosis occurs in between our hand tissue, giving us our fingers
Cell growth
,Proliferating cells undergo cycles of cell division and growth (during which they
synthesize macromolecules and prepare for the next division)
In which stage of the cell cycle is folate important?
S - DNA synthesis bc folate needed to make 3/4 nucleotides
Hypertrophy vs hyperplasticity
hypertrophy = increase in cell size, these cells eat more
hyperplasia = increase in cell number
Cell Differentiation
progenitor cell receives stimuli from environment and responds by acquiring new
morphological, structural, and functional characteristics --> new cell identity
T/F: Cell differentiation is unidirectional
True - once a cell has differentiated it can't go back (very rare!)
Terminal differentiation
final stage of a cell in which it is highly specialized; can no longer divide and make
more cells
What is cell identity affected by?
transcription factors (clarify!)
What cell types are easier to transdifferentiate?
cells that are developmentally close such as hepatocytes to exocrine pancreas cells
are easier to differentiate
Pattern Formation
cells become organized into tissues, organs, and organ systems to give rise to
functional organism, initially form body plan and then develop detailed structures
Body plan symmetry
,Bilateral symmetry with respect to craniocaudal axis
Left-right axis defined by organs that are asymmetric
Morphogenesis
development of morphological characteristics - finger development, 4 chambers of
the heart
- differential cell prolif., selective cell-cell adhesion, changes in cell shape/size,
apoptosis involved in this
Milestones in Embryonic Development
2 weeks: initial divisions
Day 14: Gastrulation
Days 19-21: Neurulation
Days 21-24: Future head, neck, mouth, nose
Weeks 3-8: Beginning or organ formation
Week 8: Fetus formed
Gastrulation
3 distinct tissues begin to form, no more embryonic stem cells, occurs around day 14
Neurulation
beginning of future nervous system, formation of neural tube
Ovulation
ovum (egg) is released from ovary at day 14 of cycle
Fertilization
occurs in the fallopian tube - head of sperm fuses with oocyte membrane and its
pronucleus enters cytoplasm, pronuclei initially separated but then fuse to become
zygote and undergoes rapid cell division
Implantation
, zygote has become blastocyte, now arrives at the uterus and implants into uterine
lining
Morula
loosely packed ball of cells that forms a few days after fertilization, cells then start
differentiating
Compaction
cells transition from a loose arrangement to tightly packed arrangement, first
differentiation in mammalian development - involves separation of trophoblast from
inner cell mast, regulated by membrane polarization
- results in external polarized cells and internal non polarized cells
When does compaction occur
at 16 cell morula stage
External polarized cells
trophoblast (will give rise to the outer layer membrane and placenta) with tight
junctions to seal the inner cells off
Internal non polarized cells
inner cell mass (will give rise to the embryo) with gap junctions to exchange
substances
Cavitation
formation of blastocyte at 32 cell stage, involves formation of blastocoele and non
polarized cells form inner cell mass (ICM gives rise to the embryo)
Blastocoele
fluid filled cavity in blastocyst
When does the blastocyte implant to the uterine wall?
Day 6-7 of development
