Exam 3: Heredity and Environment

When the 23 pairs of chromosomes duplicate and form two complete sets of the genome, this process is referred to as "duplication."

The most common extra-chromosome condition is fragile X syndrome.

Eyeballs change shape at typical stages of development, including puberty and middle adulthood. This makes it more likely that _____ will increase at puberty, and _____ will decrease during middle adulthood.

Almost every trait is polygenic, which means it is affected by many genes.

Fraternal twins are also called _____ twins.

An allele is a variation that makes a gene different in some way from other genes for the very same characteristic.

_____ cells are able to produce any other cells.

Research indicates that alcoholism is caused by _____.

Define genotype and phenotype, explain the impact of both on an individual's traits, and give an example of each.

_____ are more likely to be carriers of X-linked traits, and _____ are more likely to express them.

Justin and Jacob are identical twins. They are the result of _____.

Approximately once in every _____ births, a newborn survives with 45, 47, or even 48 or 49 chromosomes instead of the usual 46.

An individual's inherited biochemistry reacts to alcohol in different ways, causing various reactions in humans, including all the following EXCEPT _____.

Consultation and testing by trained experts that enable individuals to learn about their genetic heritage, including harmful conditions they could pass along to any children they might conceive, is referred to as "_____."

Genes and alleles for alcoholism have been found exclusively on the Y chromosome.

Jenny learned in her high school science class that a female has a(n) _____ on the 23rd pair of chromosomes.

Eight-year-old Joe has no difficulty seeing things near him but sometimes struggles to see things in the distance. Joe gets his eyes checked and is told that he does not yet need corrective lenses for nearsightedness. Instead, drawing on current research, the ophthalmologist advises that he _____.

The general term for the techniques designed to help infertile couples conceive and then sustain a pregnancy is _____.

_____ refers to a trait that is affected by many factors, both genetic and environmental, that enhance, halt, shape, or alter the expression of genes, resulting in a phenotype that may differ markedly from the genotype.

Describe the difference between monozygotic and dizygotic twins, including how each type of twin is conceived.