Back to the full dot-point answer
VICBiologyQuick questions
Unit 2: How does inheritance impact on diversity?
Quick questions on Genes, alleles and the genome: VCE Biology Unit 2
10short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is gene?Show answer
A gene is a length of DNA at a specific location (a locus) on a chromosome that codes for a functional product. Most genes code for a polypeptide (a protein or part of one) by being transcribed to mRNA and translated. Other genes code for functional RNAs (tRNA, rRNA, microRNAs).
What is allele?Show answer
An allele is a variant of a gene. Most genes exist in two or more allelic forms in a population because of historical mutations.
What is genome?Show answer
A genome is the complete set of DNA in a cell, including:
What is genotype and phenotype?Show answer
Two more essential terms that build on the above.
What is why the distinction matters?Show answer
Sloppy use of "gene" when you mean "allele" is the single most common mistake in VCE genetics responses.
What is saying "she has the gene for cystic fibrosis"?Show answer
Everyone has the CFTR gene. Carriers and affected individuals have specific disease-causing alleles of the CFTR gene.
What is confusing locus and allele?Show answer
A locus is a position; an allele is one of the variants found at that position.
What is mixing up "homologous chromosomes" and "sister chromatids"?Show answer
Homologous chromosomes are a pair (one from each parent), with the same genes but possibly different alleles. Sister chromatids are two identical copies of one chromosome, joined at the centromere after DNA replication.
What is treating the genome as just genes?Show answer
Genes are about 2% of the human genome; the other 98% is non-coding regulatory and structural DNA.
What is saying "genotype = phenotype"?Show answer
Genotype is the genetic make-up; phenotype is the observable trait. Many genotypes can give the same phenotype (PP and Pp both produce purple flowers), and one genotype can produce different phenotypes in different environments.