Trisomy 21,or Down Syndrome,occurs When There Is a Normal Diploid

question 28

Multiple Choice

Trisomy 21,or Down syndrome,occurs when there is a normal diploid chromosomal complement but one (extra) chromosome 21.Although fertility is reduced in both sexes,females have higher fertility than males.Van Dyke et al.(1995; Down Syndrome Research and Practice 3[2]:65-69) summarize data involving children born of Down syndrome individuals.Given the fact that conceptuses with 48 chromosomes (four chromosome 21s) are not likely to survive early development,what percentage of surviving offspring would be expected to have Down syndrome if both parents have Down syndrome?

• A)One-third of the surviving offspring would be expected to have Down syndrome.
• B)All the children would be expected to have Down syndrome.
• C)None of the surviving offspring would be expected to have Down syndrome.
• D)Two-thirds of the surviving offspring would be expected to have Down syndrome.
• E)One-half of the surviving offspring would be expected to have Down syndrome.

Comprehend the concept and calculation of conditional probability.

Analyze the independence of events through probability.

Utilize Venn diagrams and tree diagrams for visual representation of event relationships.

Understand the concepts of experiments and sample spaces.

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Definitions:

Spatial-Relations Intelligence

The ability to visualize and manipulate objects and space in one's mind, a key component of Howard Gardner's theory of multiple intelligences.

Naturalist Intelligence

The ability to recognize, categorize, and draw upon certain features of the environment, as one of Howard Gardner's multiple intelligences.

Heuristics

Problem-solving strategies that use a practical, less precise method for making immediate decisions or finding satisfactory solutions.

Algorithms

Precise, step-by-step procedures or sets of rules to be followed in calculations or problem-solving operations, often used in mathematics and computer science.