Genetics Review

Modern dogs are direct descendants of the gray wolf. They first appeared about 130,000 years ago. Today, there are about 150 different breeds of domestic dogs. The great variety of modern dogs can best be explained by 

• Selective breeding over many years
• natural selection favoring wolves over dogs
• the cloning of domestic dogs
• genetic alterations in gray wolves alive today

In rats, black coat color is dominant over white coat color. If some of the offspring of a cross between a black rat and a white rat are white, the black rat must have been

• a polyploid
• a mutation
• heterozygous
• homozygous

Which cell process occurs only in organisms that reproduce sexually?

• Mitosis
• Meiosis
• Replication
• Mutation

In the early 1900s, experiments were conducted on two caterpillar species. The members of the two species were divided into two groups. One group of each species was placed under red light, while the other group of each species was kept in the dark. When the caterpillars developed into butterflies, their wings showed extreme color differences. Exposure to the red light resulted in intensely colored wings, while those kept in the dark had paler wing colors. The color differences were most likely due to

• Mutations in the color-producing genes
• The caterpillars in the red light producing more DNA
• The caterpillars in the dark evolving less than those in the light
• Gene expression being affected by the environment

Which statement best describes the relationship between cells, DNA and proteins?

• Cells contain DNA that controls the production of proteins
• Cells are linked together by proteins to make different kinds of proteins
• DNA is composed of proteins that carry coded information for how cells function
• Proteins are used to produce cells that link amino acids together

Which sequence best describes the steps in genetic engineering?

• Identify the gene --> insert the gene into a bacterium --> remove the gene --> extract the enzyme
• insert the gene into a bacterium --> identify the gene --> remove the gene --> extract the enzyme
• identify the gene --> remove the gene --> insert the gene into the bacterium --> extract the enzyme
• remove the gene --> extract the enzyme --> identify the gene --> insert the gene inot the bacterium

In down syndrome, a person has an extra

• protein
• chromosome 21
• amino acid
• enzyme

Which best indicates the correct process for each event indicated?

• Formation of Egg- mitosis;

  Formation of Sperm - mitosis;

  Growth of Embryo - meiosis
  

• Formation of Egg - mitosis;

  Formation of Sperm - meiosis;

  Growth of Embryo - mitosis
  

• Formation of Egg - meiosis; Formation of Sperm - mitosis; Growth of Embryo - meiosis

• Formation of Egg - meiosis

  Formation of Sperm - meiosis

  Growth of Embryo - mitosis
  

When an organism reproduces asexually, it usually has

• only one parent and half as much DNA
• two parents and twice as much DNA as either parent
• one parent and the same chromosome number as the parent
• two parents and the same chromosome number as each parent

In gel electrophoresis, the fragments at the lower end of the gel are

• larger and move faster
• larger and move slower
• smaller and move faster
• smaller and move slower