Introduction to cytology Flashcards
Branch of Genetics which study the cell specifically the chromosome. It is developed from two separate sciences: cytology and genetics.
Cytogenetics
Cytogenetics is developed from two separate sciences
Cytology and genetics
It deals with the composition and structure of the chromosome and its role in hereditary and development of related disease.
Cytogenetics
concern with the transmission of genes from parent to offspring or from one generation to another and the outcome of the offspring’s trait.
Transmission genetics(hereditary).
study of how genetic works at the molecular level (DNA and RNA), this include gene replication, expression, regulation and mutation.
Molecular genetics.
genetic variation within a given population and the role of the environment (epigenetics) in the outcome of a trait.
Population genetics.
Fields of Genetics
Transmission genetics(hereditary).
Molecular genetics.
Population genetics.
Clinical application of Cytogenetics
Diagnosis, prognosis and monitoring
Therapeutic management
DNA finger printing (DNA profiling)
Diagnosis leukemia and solid tumor
(cancer cytogenetics).
identifying the specific location, arrangement and structure of gene in a chromosome.
Gene mapping
This may help in the diagnosis of genetic diseases.
Gene mapping
Can be determine who is at risk of genetic condition among family members
Gene mapping
treatment and management
Gene therapy
DNA finger printing (DNA profiling)
Paternity testing
Forensic
Augustinian friar, scientist.
Father of Genetics.
He studied Hereditary through the experiment of pea plants.
GREGOR MENDEL
German biologist
Founder of Cytogenetics.
Discovered mitosis.
WALTHER FLEMMING
German biologist
He developed the chromosomal theory of inheritance.
THEODORE BOVERI
Described the structure of DNA as double helix.
The discovery give rise to Modern Molecular biology
JAMES WATSON AND FRANCIS CRICK
The DNA is the hereditary materia according to
OSWALD AVERY, COLIN MCLEOD, MACLYN MCARTHY.
Discovered the Genetic code these are information that is encoded in genetic material
MARSHAL NIRENBERG AND HEINRICH MATTHAEI
Discovered the Polymerase Chain Reaction (PCR)
Which enable DNA or RNA to be reproduced in vitro.
KARY MULLIS
was launched, an international research project in 1990
HUMAN GENOME PROJECT
Provide a complete and accurate DNA base pairs that make up a human genome
HUMAN GENOME PROJECT
To identify an estimated 30, 000 genes of human.
HUMAN GENOME PROJECT
The research outcome has a major impact on the development in the field of medicine, biotechnology, and life sciences
HUMAN GENOME PROJECT
became the 1st genetic disease to be treated using gene therap in 1993
Cystic fibrosis
the 1st bacterial genome sequence in 1995
Haemophilus influenza
the completion of human genome in the year?
2000 2003
whole organs grow in culture in the year
2010
single cell organism with out nucleus
e.g. bacteria and archaea.
PROKARYOTES
more complex cell with nucleus and many organelles.
e.g. human, plants, animals and fungi.
EUKARYOTES
All cells of the body except sex cells.
SOMATIC CELLS
SEX CELLS/GAMETES
Sperm cell and ova.
There are ___ types of somatic cells in the bodys
200
A cycle in dividing cell which leads to cell division.
CELL CYCLE
A series of events that take place on a cell in preparation for cell division.
CELL CYCLE
2 Major stages of cell cycle
INTERPHASE
MITOTIC or M PHASE
similar activity with G1
G2 (gap 2)
The resting stage of cell cycle.
Constant production of protein and increasing in size.
INTERPHASE
constant synthesis of RNA to produce protein, increase in size of the cell.
G1 (gap 1)
synthesis or duplication of DNA to ensure daughter cells receive full set of DNA as of parent cell.
S phase
cessation of cell division either temporarily ( liver cells) or permanently (neurons).
G0
Types of cell division.
Mitosis
Meiosis
chromatin condense to form chromosomes
nucleolus disappear
centrioles migrates to opposite poles of the cell
spindle fibers network form.
PROPHASE
spindle fibers attach to chromosomes via kinetochore near the centromere.
chromosome align on the metaphase plate.
METAPHASE
spindle fibers shorten, kinetochore separates
chromatids (daughter chromosomes) are pulled apart and begin moving to either side of cell poles.
ANAPHASE
the daughter chromosomes arrive at respective poles.
spindle fibers disappear.
TELOPHASE
divides the nuclei, cytoplasm, organelles and cell membrane into 2 cells.
CYTOKINESIS
Is a type of cell division (eukaryotes) that produces haploid sex cells or gametes.
MEIOSIS
Also known as reduction division.
MEIOSIS
reduction of chromosomes from diploid (2n) to haploid (n)
Meiosis I
the same as in mitosis, producing 4 haploid cells.
Meiosis II
Chromosomes become visible
Crossing over of homologous chromosomes
Prophase I
Chromosomes align at the center
METAPHSASE I
homologous chromosomes separates but sister
chromatids are still attached
ANAPHASE I
Production of 2 haploid (n) daughter cells
TELOPHASE I and cytokinesis
Homologous chromosomes pair up to form tetrads ( 4 chromatins).
Prophase I
a pair of chromatins similar in size and genetic content.
Homologous chromosome
(crossing over)- homologous chromosomes exchange genetic materials to create 4 unique chromatids.
Genetic recombination
Consist of prophase II, anaphase II, metaphase II and telophase II
Meiosis II
The process is the same as mitosis.
Meiosis II
At the end of the this cell cycle, 4 genetically different daughter cells are produced.
Meiosis II
G1 -__ hours
S phase- __ hours
G2 phase-__
M phase- __
G1 - 9 hours
S phase- 10 hours
G2 phase-four and one-half hours
M phase- one-half hour
regulated by external and internal event.
Initiation and inhibition of cell division
a hormones that promotes cell division.
Human growth hormone (HGH)
overcrowding cells inhibit cell division
Space
Internal event of regulation of cell division
Cell cycle checkpoints
External event of regulation of cell division
Human Growth Hormone
Space
Size of the cell
a. Ensures if the size of the cell is ready for cell division.
b. Ensures if necessary proteins are made for cell division.
c. Ensures that DNA is error free before it will be copy.
G1 checkpoint
If the cells failed to meet the requirement it will proceed to __ until it is ready.
G0
DNA synthesis checkpoint
G2 checkpoint
a. Checks whether DNA is replicated correctly (no mutations)
b. If not, it stops the progression to correct the problem by the action of DNA repair system.
c. If the DNA is beyond repair the cell will undergo apoptosis or programmed cell death.
G2 checkpoint
Ensures that the cell’s spindle fibers are properly aligned in metaphase before the chromosomes are separated in anaphase.
Mitosis checkpoint (during metaphase)
Promotes cell cycle
Positive regulation
Stops cell cycle
Negative regulation
- Transcription factor (MYC)
- Cyclin –dependent kinases (CDKs)
- EGFR- epidermal growth factor receptors
Proto-oncogenes
Tumor suppressor genes
Negative regulation
result to uncontrolled cell growth and proliferation (malignancy).
oncogenes
lead to uncontrolled cell growth and eventually malignant condition.
Mutation of tumor suppressor genes
Proto-oncogenes
- Transcription factor (MYC)
- Cyclin –dependent kinases (CDKs)
- EGFR- epidermal growth factor receptors
p53 located in chromosome 17 (short arm). 50 % of cancer cases is due to p53 mutation.
e.g. breast cancer, colorectal, liver and ovarian.
Tumor suppressor gene
Repair damage DNA before replication.
When DNA damage is beyond repair, it stimulates cell apoptosis.
p53 functions
