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

question 34

Essay

Trisomy 21,or Down syndrome,occurs when there is a normal diploid chromosomal complement of 46 chromosomes plus one (extra)chromosome #21.Such individuals therefore have 47 chromosomes.Assume that a mating occurs between a female with Down syndrome and a normal 46-chromosome male.What proportion of the offspring would be expected to have Down syndrome? Justify your answer.

---

Definitions:

Antagonist

A substance that blocks or dampens a biological response by binding to and blocking a receptor rather than activating it.

Neurotransmitter

Compounds responsible for transmitting signals between neurons through synapses within the nervous system.

Agonist

An agonist is a chemical or drug that binds to receptors in the brain and activates them, mimicking the effects of naturally occurring substances and potentially influencing physiological and psychological processes.

Autonomic Neuron

A nerve cell that governs function in the autonomic nervous system, responsible for involuntary body functions like heart rate and digestion.