Hematology Progress Exam
(125 Items) - 1/3 fully solved &
updated (graded A+)
One chromosome breaks off and becomes attached to a different
chromosome:
a. Addition
b. Deletion
c. Inversion
d. Translocation - answer D. TRANSLOCATION
CHROMOSOMAL CHANGES
TRANSLOCATIONS
Most common type of DNA change that can lead to leukemia.A translocation
means that a part of one chromosome breaks off and becomes attached to a
different chromosome.
The point at which the break occurs can affect nearby genes—for example, it
can turn on oncogenes or turn off genes that would normally help a cell to
mature.
DELETIONS
Occur when part of a chromosome is lost.
This may result in the cell losing a gene that helped keep its growth in check,
for example, a tumor suppressor gene.
INVERSIONS
Occur when part of a chromosome gets turned around, so it is now in reverse
order.
,This can result in the loss of a gene (or genes) because the cell can no longer
read its instructions in protein translation.
ADDITION
An extra chromosome or part of a chromosome is gained.
This can lead to too many copies of certain genes within the cell.
This can be a problem if one or more of these genes are oncogenes.
The most versatile type of stem cell, can develop into any human cell type,
including development from embryo into fetus:
a. Totipotential Stem Cells
b. Multipotential Stem Cells
c. Pluripotential Stem Cells - answer A. TOTIPOTENTIAL STEM CELLS
TYPES OF HUMAN STEM CELLS
Functionally, three types of human stem cells exist:
1. Totipotential stem cells
These cells are present in the first few hours after an ovum is fertilized.
Totipotential stem cells, the most versatile type of stem cell, can develop into
any human cell type, including development from embryo into fetus.
2. Pluripotential stem cells
These cells are present several days after fertilization.
Pluripotent stem cells can develop into any cell type, except they cannot
develop into a fetus.
3. Multipotential stem cells
These cells are derived from pluripotent stem cells.
They can be found in adults, but they are limited to specific types of cells to
form tissues.
, For example, bone marrow stem cells can produce all types of blood cells,
bone cartilage, and adipose (fat) cells.
The promyelocyte stage lasts about:
a. 4 hours
b. 12 hours
c. 15 hours
d. 24 hours
e. 4.3 days - answer D. 24 hrs
PROLIFERATIVE PHASE
Myeloblast: 15 hours
First identifiable cell in the granulocytic series
Constitute approximately 1% of the total nucleated bone marrow cells
Stage lasts approximately 15 hours
Promyelocyte: 24 hours
Constitutes approximately 3% of the nucleated bone marrow cells
This stage lasts about 24 hours
Myelocyte
Approximately 12% of the proliferative cells existing in this stage
Myelocyte to metamyelocyte lasts an average of 4.3 days
Once the metamyelocyte stage has been reached, cells have undergone four
or five cell divisions and the proliferative phase comes to an end
MATURATION-STORAGE PHASE
Metamyelocytes 45%
Band 35%
(125 Items) - 1/3 fully solved &
updated (graded A+)
One chromosome breaks off and becomes attached to a different
chromosome:
a. Addition
b. Deletion
c. Inversion
d. Translocation - answer D. TRANSLOCATION
CHROMOSOMAL CHANGES
TRANSLOCATIONS
Most common type of DNA change that can lead to leukemia.A translocation
means that a part of one chromosome breaks off and becomes attached to a
different chromosome.
The point at which the break occurs can affect nearby genes—for example, it
can turn on oncogenes or turn off genes that would normally help a cell to
mature.
DELETIONS
Occur when part of a chromosome is lost.
This may result in the cell losing a gene that helped keep its growth in check,
for example, a tumor suppressor gene.
INVERSIONS
Occur when part of a chromosome gets turned around, so it is now in reverse
order.
,This can result in the loss of a gene (or genes) because the cell can no longer
read its instructions in protein translation.
ADDITION
An extra chromosome or part of a chromosome is gained.
This can lead to too many copies of certain genes within the cell.
This can be a problem if one or more of these genes are oncogenes.
The most versatile type of stem cell, can develop into any human cell type,
including development from embryo into fetus:
a. Totipotential Stem Cells
b. Multipotential Stem Cells
c. Pluripotential Stem Cells - answer A. TOTIPOTENTIAL STEM CELLS
TYPES OF HUMAN STEM CELLS
Functionally, three types of human stem cells exist:
1. Totipotential stem cells
These cells are present in the first few hours after an ovum is fertilized.
Totipotential stem cells, the most versatile type of stem cell, can develop into
any human cell type, including development from embryo into fetus.
2. Pluripotential stem cells
These cells are present several days after fertilization.
Pluripotent stem cells can develop into any cell type, except they cannot
develop into a fetus.
3. Multipotential stem cells
These cells are derived from pluripotent stem cells.
They can be found in adults, but they are limited to specific types of cells to
form tissues.
, For example, bone marrow stem cells can produce all types of blood cells,
bone cartilage, and adipose (fat) cells.
The promyelocyte stage lasts about:
a. 4 hours
b. 12 hours
c. 15 hours
d. 24 hours
e. 4.3 days - answer D. 24 hrs
PROLIFERATIVE PHASE
Myeloblast: 15 hours
First identifiable cell in the granulocytic series
Constitute approximately 1% of the total nucleated bone marrow cells
Stage lasts approximately 15 hours
Promyelocyte: 24 hours
Constitutes approximately 3% of the nucleated bone marrow cells
This stage lasts about 24 hours
Myelocyte
Approximately 12% of the proliferative cells existing in this stage
Myelocyte to metamyelocyte lasts an average of 4.3 days
Once the metamyelocyte stage has been reached, cells have undergone four
or five cell divisions and the proliferative phase comes to an end
MATURATION-STORAGE PHASE
Metamyelocytes 45%
Band 35%
