Question

1.1. List the major parts of a chromosome.
1.2. List the types of chromosomes based on centromere position.
1.3. Describe ways that chromosomes are obtained, prepared, and detected
1.4. Explain how atypical chromosome numbers arise.
1.5. Describe syndromes associated with incorrect chromosome number.
1.6. Explain how a typical chromosome structures arise.
1.7. Describe syndromes associated with specific variants of chromosome structure.
1.8. Explain how a person could inherit both copies of a DNA sequence from one parent.
1.9. Describe how inheriting both copies of DNA from one parent can affect health.

please help me to answer this question and please if i could get the reference in apa format. thank you in advance!

Answer 1

1.1. The major parts of a chromosome are: chromatids, centromere , satellite, chromonemata, telomere, secondary and primary constrictions and satellite.

1.2. Depending on the position of the centromere, the types of chromosomes are :
Telocentric - centromere is at one end
Metacentric - centromere is in the middle
Submetacentric- centromere is a bit above than being in middle
Acrocentric - no centromere present

1.3. Chromosomes can be obtained from blood sample or from bone marrow sample. They are prepared on slides or special kits that are meant for chromosmal assays. The ways in which they can be studied are either by karyotyping or my chromosomal microarray techniques or by comb method .

1.4. Atypical chromosomes are the chromosomes that have some or the other disorder like structure or number. These abormalities in the chromosomes arise due to abnormal meiotic divisions or segregations or duplication ,translocations, inversions, deletions etc. of the chromosomes that produce increasing or decreasing number of chromosomes.

1.5. Syndromes associated with incorrect chromosomal numbers :

• Monosomy - only one pair of chromosomes are formed. Can lead to diorders like Turner's syndrome where the female have one X chromosome causing webbed neck, short neck, hairline receeding etc
• Trisomy - More number of chromosomes are formed like XXY, XXXY or XYY. These lead to disorders like Down's syndrome, Klinefelter's syndrome, Edward's syndrome etc.

1.6. A typical chromosome is found in the nucleus of the cell. The DNA gets packaged in a compact form via the chromatin formation and the histone proteins. The DNA that are tend to form the chromosomes wrap around the histones to form the nucleosomes. These then condense to form chromatin structures that further condense and gets packaged to form chromosomes.

1.7. Same as the answer in 1.5.

1.8. Normally, a person could inherit both copies of the chromosomes DNA sequence from both parents  by the process of meiosis. In meiosis there is a step called crossing over that occurs in the pachytene stage of prophase I of  meiosis I . Here the two non sister chromatids of homologous chromosomes each belonging to the mother and father cross over one another by an arm and share the DNA sequences giving rise to the offsprings. But in certain cases, the crossing over might not occur and the entire DNA is transferred from one parent itself. This gives rise to extra copies of the same chromosome that produces anomalies in very few cases

1.9. Generally this does not affect the health.