Biology - Genetics Part 1

What is a result of crossing over during meiosis?

• genetic variation

• extra chromosomes formed

• loss of chromosomes

• production of gametes

Which best describes polygenic traits?

• traits that are always dominant to other traits

• traits that are always masked by any other traits

• traits that skip generations and appear in the offspring of later generations

• traits that are determined by a combined effect of more than one pair of genes

Examine the Punnet square below.

What is the most likely phenotype of the two parents?

• type A and B

• type A and O

• type A and AB

• type O and AB

Which best describes a Punnett square that is used to make predictions about one trait?

• dihybrid

• monohybrid

• pedigree chart

• independent assortment

The diagram below shows a change that occurred in a pair of chromosomes during meiosis.

After fertilization, the alteration that occurred will most likely

• change the number of chromosomes found in each body cell.

• be passed on to every body cell that develops from the gamete.

• increase the number of body cells that make up the embryo.

• inhibit the growth and development of the developing embryo.

Human height, eye color, weight, and skin color are examples of which type of trait?

• dominant

• polygenic

• recessive

• sex-linked

Two children were born at the same time in a hospital. However, the identification bracelets on the children became mixed up. If Baby #1 is blood type O, what are the genotypes of the parents who produced Baby #1?

• IBi and IAIB

• IAIA and ii

• IAi and IBi

• IAIB and ii

Hemophilia is a sex-linked disorder. If a man has hemophilia and a woman is a carrier of the disorder, what percent of the offspring will have hemophilia?

• 25%

• 50%

• 75%

• 100%

Which best explains why a trait visible in one generation skips the next generation and reappears in the third generation?

• The trait is caused by a dominant allele.

• The trait is caused by a recessive allele.

• A mutation occurs in the third generation.

• A mutation occurs in the second generation.

In which way does meiosis most likelyincrease genetic variation?

• It prevents crossing over from occurring.

• It divides the maternal and paternal chromosomes.

• It proceeds at a slower rate and allows for more mutations.

• It keeps the maternal and paternal chromatids together in a cell.