3.1 Genes Flashcards
What is a gene?
A gene is a heritable factor that consists of a length of DNA and influences a specific characteristic.
What occupies a specific position on a chromosome?
A gene occupies a specific position on a chromosome.
Define alleles.
Alleles are the various specific forms of a gene.
How do alleles differ from each other?
Alleles differ from each other by one or a few bases.
What is the genome?
The genome is the whole of the genetic information of an organism.
How are new alleles formed?
New alleles are formed by mutation.
What causes mutations?
Mutations can be caused by errors in DNA replication, exposure to radiation, and contact with certain chemicals known as mutagens.
What is a base-substitution mutation?
A base-substitution mutation is a mutation that changes one nitrogenous base in a sequence.
What was the aim of the Human Genome Project?
To determine the complete sequence of the human genome and identify every gene it contains.
Describe the outcome and significance of the Human Genome Project.
The project mapped and sequenced the human genome, facilitating advances in medicine, genetics, and anthropology.
Explain the cause of sickle cell anemia.
Sickle cell anemia is caused by a specific base substitution mutation, changing the sixth amino acid in the beta hemoglobin polypeptide from glutamic acid to valine.
What is the genetic inheritance pattern of sickle cell anemia?
Sickle cell anemia is inherited in an autosomal recessive pattern.
How can databases be used in genetics?
Databases can be used to study genomes and determine differences in the base sequence of a gene in two species.
What is an example of a database used for comparing genetic sequences?
The NCBI’s GenBank database is a widely used resource for comparing genetic sequences.
Compare the number of genes in humans with other species.
Humans have about 20,000 protein-coding genes, less than some plants like rice with about 35,000, but more than some animals like the fruit fly with about 14,000 genes.
