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