HEREDITY
CROSSOVER
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Chromosomes (pairs 1-22) are arranged by size
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Sex chromosomes are found at the end
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A normal karyotype has 46 chromosomes or 23 pairs
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Having missing or extra chromosomes does not indicate a disorder
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Detailed explanation-1: -Answer and Explanation: The statement (b) All eukaryotic karyotypes contain 46 chromosomes is not true.
Detailed explanation-2: -But if meiosis doesn’t happen normally, a baby may have an extra chromosome (trisomy), or have a missing chromosome (monosomy). These problems can cause pregnancy loss. Or they can cause health problems in a child. A woman age 35 years or older is at higher risk of having a baby with a chromosomal abnormality.
Detailed explanation-3: -A change in the number of chromosomes can cause problems with growth, development, and function of the body’s systems. These changes can occur during the formation of reproductive cells (eggs and sperm), in early fetal development, or in any cell after birth.
Detailed explanation-4: -So, the correct statement is ‘A karyotype is an arrangement of chromosomes from a cell based on their shape, size, and position of their centromeres’.