Genetics Review

What do you call a section of DNA that codes for a specific trait?

• nucleus
• chromosome
• gene
• DNA

How many chromosomes are found in human egg and sperm cells?

• 20
• 23
• 26
• 46

Which of the following is the genotype for a homozygous recessive trait?

• gg
• Gg
• GG

What is one or more alternative forms of a gene?

• chromosome
• genotype
• phenotype
• allele

The punnett square shows a cross between two flowering plants. One parent has pink flowers (Pp) and the other parent has white flowers (pp). What percentage of pink flowers will you have? 

• 0
• 25
• 50
• 75

^{_{Scientists learned that the allele for long eyelashes (L) is dominant to the allele for short eyelashes (l), and the allele for strong eye muscles (M) is dominant to the allele for weak eye muscles (m). The Punnett square below show a cross between two of these organisms. What fraction of the offspring will most likely have long eyelashes with weak eye muscles?}} 

• 3/16
• 9/16
• 1/16
• 0/16

The cross of a plant with white flowers (WW) and a plant with Green flowers (ww) is shown in the Punnett square below. What would be the genotype and phenotype of the offspring from this cross?

• Ww - white
• Ww - green
• WW - white
• ww - green

B-blue skin b-green skin E-big ears e-small ears
 The phenotype for a boy smurf is homozygous dominant for both traits above. What is his genotype?

• BBEE
• bbee
• BBEe
• BbEe

Which of the following is a phenotype?

• Aa
• red hair
• heterozygous genes
• mutated DNA

In a heterozygous genotype, the ___________ allele takes over in the phenotype.

• recessive
• dominant
• lower case letter
• both