These Condensed Chromosomes Observed Biology Essay

The image was taken from the slide prepared during practical category. These condensed chromosomes observed were stained utilizing a Cytogenetics technique called Giemsa stria that reveal structural characteristics of the chromosomes ; the figure above shows different types of chromosome. Point ( A ) as shown on the figure represent the longest chromosomes observed on the metaphase spread, ( B ) represent the metacentric chromosome, ( C ) Submetacentric chromosome and ( D ) is the acrocentric chromosome. The chromosome were observed at 100X magnification

Fig 2: longest chromosome

Q arm

P arm



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Sister Chromatids

Centromere in the center of chromosome keeping two sisters chromatids together is represented in the above figure ( 2 ) , the P arm is the shortest and the Q arm is the longest arm besides are seeable. Telomeres are located in the terminal caps and protect the chromosomes against homologous and non-homologous recombination.

Question 2: Draw an acrocentric, metacentric and submetacentric chromosome including the G-banding form. ( 1 points )

Figure: 3 chromosome construction and G- stria form

( C ) Chromosome acocentric

( B ) Chromosome submetacentric

( A ) Chromosome metacentric

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Q arm

The above figure ( 2 ) was drawn by me. Letter A represent the metacentric chromosome where the kinetochore is placed in the center of chromosomes into two weaponries with about equal length. B is the submetacentric chromosomes in which the kinetochore is a small off from the centre and hence chromatid of one side are somewhat longer than the other chromatid. The last type of chromosome represented in this image is called acrocentric as the kinetochore is d closer to one side of the chromatid go forthing the chromatid on the opposite side is really longer than the other side.

Question 3: Count the mean figure of chromosomes in 10 cells – demo your workings. ( 1point )

Fig 4: The mean figure of chromosomes in the cells

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Interphase karyon

Interphase karyon


Chromosomes in metaphase spread

This figure shows Tree one-fourth of the field of position observed in the microscope. The figure of the chromosomes was counted in brace as a diploid being is comprised of 2 transcripts of every chromosome. To number the figure of these chromosomes is besides depending from the species to species. In fact the human nucleus comprises of 22 brace of autosomal, and 2 brace of sex chromosomes. Particularly 82 figure of chromosomes were about counted from each metaphase spread observe in this field of position incorporating Hela cells. So in entire 210 chromosomes were observed in the field of position. This peculiar image as observed at 40 X magnification

Question 4: Why is Giemsa set staining of chromosomes used in cytogenetics research labs? ( 1 point )

Condensed chromosome during metaphase spread could be stained with Giesma banding which is a utile analytical method in Cytogenetics to bring forth a seeable karyotype. Routine G banding with trypsin in Cytogenetics is utile as it gives each chromosome a distinctive banded form that enable a clear designation of isolate or distinct parts all along each chromosome and the chance to analyze for chromosomal instability by standard microscopic. In the clinical scene, the technique is utile to measure for any chromosomal instability in a broad scope of patients.

Question 5: Describe the disease that the patient whose cells were used to do the cell line had. ( 2 point )

The Hela cells taken from Henritta Lack tumour had malignant neoplastic disease. She suffered from cervical malignant neoplastic disease. Cervical malignant neoplastic disease is the most common types of malignant neoplastic disease that affect adult females ‘s generative variety meats. This malignant neoplastic disease originates in the lower, narrow portion of the womb. The disease is characterized by malignant tumors ( the aberrant growing ) from cervical cells. Most cervical malignant neoplastic diseases arise in the squamous epithelial cells run alonging the neck. It has been proven that the Human Papilloma virus ( HPV ) is the cause of the bulk of different type of cervical malignant neoplastic diseases as all Hela cells contain HPV.

Question 6: During which phase of mitosis is the chromosomes in their most condensed province and best for karyotyping? ( 1 point )

Methaphase is the best phase of cell division ( mitosis ) where Chromosomes can be easy seen with a light microscope in their condensed signifier observed at 1000 ten to transport out the karyotyping.

Question 7: Name two beginnings of cells typically used for karyotyping in a hospital-based Cytogenetics research lab. Explain why these types of cells are used. ( 1 point )

Normally, in the infirmary -based Cytogenetics research lab, the two beginnings of cells used for Karyotyping are peripheral blood lymph cell cells and foetal tegument cells originated from the placenta or amnionic fluid. Lymphocyte cells are good beginnings as they can quickly proliferate and supply a really accessible beginning of metaphase cells that is utile for Cytogenetics. Amniotic fluid cells are besides appropriate for karyotyping as these cells can be easy grown in tissue civilization for chromosome analysis. For case, down syndrome which is genetic sciences defects status can be detected by karyotyping method from the cells obtain from the amnionic fluid.

Question 8: Imagine you are shortly to be a new parent. The physician has explained to you the consequences of your amniocentesis trial. Your 15-week old fetus has Down ‘s Syndrome caused by an unnatural figure of chromosomes.

How is an amniocentesis trial performed? ( 1 point )

Amniocentesis is the most common antenatal trial used to name chromosomal and familial birth defects by everyday cytogenetic analysis. During the process, an ultrasound image is used as a usher. With the syringe, a little sample of amnionic fluid is removed from the amnionic pouch surrounded the foetus and send to the research lab for analysis. The fluid contains all the familial brand of the unborn babe.

Describe the karyotype that typifies a Down ‘s Syndrome kid. ( 0.5 points )

The karyotype of a kid contains a three chromosomes in the 21st place, where at that place should merely be two.

Pull the affected chromosome after G-banding. ( 1 point )

Fig 6: The affected chromosome with Down syndrome after G-banding

Extra unnatural chromosome

P arm

Normal Chromosome 21

Normal Chromosome 21

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G-Banded karyotype of chromosome 21. On the right, is shown the 2 braces normal chromosomes 21 ; on the right, an extra chromosome added doing 3 transcripts of chromosomes ( trisomy )

What are the typical symptoms your kid will hold? ( 2 points )

Down syndrome symptoms differ from kid to child and can run from benign to malignant. Children with Down syndrome have some typical recognized physical visual aspect. They have craniofacial characteristics which can include an anterior and posterior flattened caput. Their unit of ammunition faces with molded eyes as a consequence of epicanthal creases, dysplastic low set of ears, little and level nose ; most of these kids have smaller caput than normal caput form. In add-on, their oral cavity is little with a stick outing lingua and dental abnormalcies every bit good as short and wide cervix. Besides their facial and physical visual aspect, kids affected with Down syndrome are at higher hazard of developing many medical conditions. Research suggests that the bulk of kids with Down syndrome have a status called hypotonus which is characterized by low musculus tone. Meaning that their musculuss appear floppy therefore are weak. Their Motricity is compromised due to their Hypotonicity ( Hecht and Hook,1994 ) .

Which diseases are your kid more likely to develop and at what age? ( 1 point )

The excess chromosome 21 that cause Down syndrome in kids affects about every organ system in the organic structure and has a annihilating effects phenotypically, every bit good as dangerous conditions. About half of kids with Down syndrome are born with inborn bosom defects Freeman et al. , ( 2008 ) . As the immune system of kids affected by Down syndrome are compromised and besides as they are exposed to autoimmune disease, they are being much more susceptible to infective diseases, such as pneumonia or hypothyroidism. Clogging sleep apnea is besides one of the status that these kids suffer, as there are soft and their skeleton is altered ensuing in the airway obstructor. Children with Down syndrome are at greater hazard of developing leukemia than normal kids. This status affected kids in detaining their physical growing, their ripening, the development of their bone, and their dental eruption. Children with trisomy have decreased buffering of metabolic reactions that lead to to hyperuricemia and increased insulin resistance.diabetes mellitus is common among them

The exact age that that most of the disease occurs can non be determined as it topic of the person.

What is the forecast for your kid? ( 2 points )

The forecast for a kid with Down syndrome depends with the underlying medical and developmental conditions. Most of the wellness jobs related with trisomy can be treated efficaciously. The life anticipation for people with Down syndrome are now double to 55 old ages since 1983.

Abnormalities in chromosome figure are damaging and normally deadly. Speculate as to why this is non the instance in Down ‘s Syndrome. ( 1 point )

Down syndrome is the most common familial upset that affects human chromosome but it is non deadly as others chromosomal status. There is a scope of fluctuation in the phenotype of the disease besides even thought there is non a remedy for the status, medical intervention to decrease the symptoms of this disease is good known and proven to be effectual.


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