Question

1. is the following sentence true or false? many human genes have become known through the study of genetic disorders.

match the genetic disorder with its description.
description genetic disorder

1. nervous system breakdown caused by an autosomal recessive allele a. phenylketonuria (pku)
2. a form of dwarfism caused by an autosomal dominant allele b. tay - sachs disease

c. achondroplasia

1. a buildup of phenylalanine caused by an autosomal recessive allele d. huntington’s disease
2. a progressive loss of muscle control and mental function caused by an autosomal dominant allele

from gene to molecule

1. what is the normal function of the protein that is affected in cystic fibrosis?
2. a change in just one dna base for the gene that codes for the protein causes sickle - shaped red blood cells.
3. what is the advantage of being heterozygous for the sickle cell allele?
4. what makes an allele dominant, recessive, or codominant?

Explanation:

• 15: Many human genes have indeed been discovered through the study of genetic disorders. For example, the gene for cystic fibrosis was identified by studying patients with the disorder.
• 16: Tay - Sachs disease is a genetic disorder that causes a breakdown of the nervous system. It is caused by an autosomal recessive allele.
• 17: Achondroplasia is a form of dwarfism caused by an autosomal dominant allele.
• 18: Phenylketonuria (PKU) is a disorder in which there is a buildup of phenylalanine. It is caused by an autosomal recessive allele.
• 19: Huntington's disease is a progressive disorder that causes a loss of muscle control and mental function. It is caused by an autosomal dominant allele.
• 20: The protein affected in cystic fibrosis is the cystic fibrosis transmembrane conductance regulator (CFTR). Its normal function is to regulate the flow of chloride ions across cell membranes.
• 21: A change in just one DNA base for the gene that codes for the protein hemoglobin causes sickle - shaped red blood cells.
• 22: Being heterozygous for the sickle cell allele provides some resistance to malaria.
• 23: An allele is dominant if it masks the effect of a recessive allele. An allele is recessive if its effect is masked by a dominant allele. An allele is codominant if both alleles are expressed equally in the phenotype.

Answer:

1. True
2. b
3. c
4. a
5. d
6. The normal function of the protein affected in cystic fibrosis (CFTR) is to regulate the flow of chloride ions across cell membranes.
7. Hemoglobin
8. Being heterozygous for the sickle cell allele provides some resistance to malaria.
9. An allele is dominant if it masks the effect of a recessive allele. An allele is recessive if its effect is masked by a dominant allele. An allele is codominant if both alleles are expressed equally in the phenotype.