How many genes are believed to constitute the human genome?
During which meiotic division is the number of chromosomes halved?
|A)||during meiosis I|
|B)||during meiosis II|
|C)||prior to meiosis I, during the S phase|
|D)||after meiosis II|
Choose the recessive human trait from the list that follows.
During which phase of meiosis does the phenomenon called crossing-over occur?
Homologous chromosomes are separated during _______________.
Which of these does not contribute to genetic variability?
|C)||having children with a close relative|
|D)||having children with someone who is not a relative|
Several variant forms of a gene for a given trait are called ______________.
A person who can pass either a widow's peak or straight hairline to the next generation is said to be _______________ for the hairline trait.
If a recessive trait, such as hemophilia, occurs more often in males than in females, it is because the gene for the trait is most likely carried on ________________.
|A)||the X chromosome|
|B)||the Y chromosome|
|C)||a mutant allele|
If Chris, who carries the gene for cystic fibrosis but does not have the disease, fathers a child with Rhonda, who also carries the cystic fibrosis gene but does not have the disease, what is the likelihood that their first-born will have cystic fibrosis?
What is an example of a codominant trait in humans?
|A)||sickle cell disease|
|C)||ABO blood groups|
Traits that are controlled by one or more genes and influenced by the environment are said to be _________________.
The fact that a woman cannot generally grow a beard is because beard growth is a(n) ________________ trait.
The normal chromosome number is referred to as _____________.
The last pair of 23 chromosomes is referred to as the _____.
In Down's syndrome, there is an extra chromosome number _____.
Which chromosomes indicate a normal male fetus?