Chapter 19 Human Biology

In human gamete production there is an average of _____ crossover events per chromosome pair

2-3

What is the probability that a woman who is a carrier for the red-green color-blindness allele and a man who is color blind will have a child who is NOT color blind?

50%

Consider the hypothetical X-linked recessive gene M. Suppose a woman expresses this gene. So does her husband. What are the chances that a child of theirs will NOT express this gene?

All of the children will express the trait.

Which of the following could be detected by preparing a karyotype?

Klinefelter syndrome

Which of the following statements accurately describes melanin's function?

Lighter skin has less of the dark-brown eumelanin that protects cells from UV damage

What tool is used to determine the probabilities of different genetic outcomes from various crosses?

Punnett square analysis

What is the function of a spliceosome?

RNA processing

Testosterone is responsible for the development of the male reproductive system, and it is produced by the testes. The development of the testes depends on the presence of a Y chromosome. What might occur if the Y chromosome is present, but the testes are unable to produce testosterone?

The testes would be present, but further male development would be arrested

What can we say about the frequency of X-linked recessive traits?

X-linked recessive traits are more common in males than in females

What would provide an EXCEPTION to Mendel's law of independent assortment?

adjacent genes on the same chromosome

A recessive phenotype will be expressed when __________

both alleles present are recessive

In the human ABO blood-typing system, an individual with A and B alleles will express both A and B phenotypes on his or her red blood cells. This is an example of __________

codominance

Which of the following results in the separation (or unlinking) of linked genes?

crossing-over during meiosis I

In eukaryotic cells DNA has the appearance of a ____

double helix

Genes provide the information needed to produce _____ in the cell

enzymes

A female is diagnosed with hemophilia, a condition caused by an X-linked recessive gene. While checking her medical history, the doctor will most likely discover that ________

her father had hemophilia but her mother did not have the disorder

Dominant alleles that cause disease are especially dangerous because _________

heterozygous individuals will develop the disease

Female autosomes plus a pair of sex chromosomes are sometimes called __________

homologous chromosomes

Nondisjunction in meiosis I results in failure of _________

homologous chromosomes to separate

When a straight-haired parent and a curly-haired parent have a wavy-haired child, this is an example of _________

incomplete dominance

Homologous pairs of chromosomes are lined up independently of other such pairs during _____

metaphase I

Which of the following events or processes can result in Patau syndrome, Turner Syndrome, or Klinefelter syndrome

nondisjunction

Crossing over, resulting in an increase in genetic variation, occurs between ____

nonsister chromatids of homologous chromosomes

DNA is composed of building blocks called ____

nucleotides

How many different kinds of gametes (with respect to a particular gene locus) are formed by an individual who is homozygous at that locus?

one

How many enzymes are typically produced from a single gene?

one

When continuous variation occurs in a phenotypic trait, the trait is likely due to _________

polygenic inheritance

The Genetic Information Nondiscrimination Act (GINA) __________

prevents insurance companies from denying coverage to healthy individuals based on the results of genetic testing

Enzyme complexes that break down protein are called _____

proteasomes

Protein-phosphorylating enzymes' role in the regulation of gene expression involves _____

protein activation

The nuclear membrane's role in the regulation of gene expression involves _____

regulating the transport of mRNA to the cytoplasm

Baldness is a sex-influenced trait. Women must inherit both recessive alleles to be bald, while men need only inherit one recessive allele. This occurs because _________

testosterone stimulates the expression of the baldness allele

Alterations in chromosomal structure or number that occur during mitosis or meiosis are seldom seen because _________

the altered genes are crucial to development and the organism does not survive to birth

True or false. X-linked recessive disorders are more commonly expressed in males than in females because males have only one copy of the X chromosome

true