3.1 Notes
Download as DOCX, PDF1 like1,150 views
This document provides notes on IB Biology Chapter 3, focusing on genes, their definitions, and related concepts such as alleles, mutations, and the human genome project. It covers the structure and functions of genes, the types of mutations including base substitution and frameshift, and various specific attributes such as gene locus and the formation of new alleles. The chapter additionally addresses comparisons of gene numbers across species and the implications of mutations on conditions like sickle cell anemia.
3.1 Notes
- 1. IB Biology Chapter 3 Notes: Genes (3.1) NAME: Word Definition Gene A heritable factor that controls specific characteristic. It is also a section of DNA that codes for a polypeptide. Allele Different forms or variants of a specific gene. Genome The whole of the genetic information of an organism. Gene mutation When the nucleotide base letter sequence of the DNA is changed. Base substitution mutation (point mutation) When a single letter in the DNA sequence is replaced with a different letter. Frameshift mutation When a single letter in the DNA sequence is added or deleted. Gene Locus A specific position of a gene on a chromosome. Human Genome Project An international research project that led to the mapping/sequencing of the entire genetic material of a human being.
- 2. 3.1.1 A gene is a heritable factor that consists ofa length of DNA and influences a specific characteristic. 3.1.9 Comparison of the number of genes in humans with other species. 3.1.2 A gene occupies a specific position (locus) on one type of chromosome. 3.1.3 The various specific forms of a gene are alleles. 3.1.4 Alleles differ from each other by one or a few bases only. 3.1.10 Use of a database to determine differences in the base sequence of a gene in two species. 3.1.5 New alleles are formed by mutation. 3.1.8 The causes of sickle cell anemia, including a base substitution mutation, a change to the base sequence of mRNA transcribed from it, and a change to the sequence of a polypeptide in hemoglobin. 3.1.6 The genome is the whole of the genetic information of an organism. 3.1.7 The entire base sequence of human genes was sequenced in the Human Genome Project. Which types of organisms have the fewest genes? Identify two organisms with more genes than humans: What is the ‘locus’ of a gene? What is an allele? What does it mean to have ‘multiple alleles’ for a trait? How do scientists determine sequence differences in two species for a gene and why is this done? What is a base substitution mutation? What gene is mutated in Sickle Cell Anemia? What base change occurs in the DNA? What amino acid change occurs in the polypeptide? Describe the effects of Sickle Cell Anemia: Describe the Human Genome Project (HGP) and its outcomes: