What you’ll learn12 learning objectivesChoose one objective for a focused lesson, or study the complete topic.17.1.1Chromosomes are made of DNA, which• State that chromosomes are made of DNA, which contains genetic information in the form of genesSyllabus objective17.1.2Gene as a length of DNA that codes• Define a gene as a length of DNA that codes for a proteinSyllabus objective17.1.3Allele as an alternative form• Define an allele as an alternative form of a geneSyllabus objective17.1.4Inheritance of sex in humans• Describe the inheritance of sex in humans with reference to X and Y chromosomesSyllabus objective17.1.5Sequence of bases in a gene determines• State that the sequence of bases in a gene determines the sequence of amino acids used to make a specific protein (knowledge of the details of nucleotide structure is not required)Syllabus objective17.1.6Different sequences of amino acids• Explain that different sequences of amino acids give different shapes to protein moleculesSyllabus objective17.1.7DNA controls cell function• Explain that DNA controls cell function by controlling the production of proteins, including enzymes, membrane carriers and receptors for neurotransmittersSyllabus objective17.1.8Protein is made• Explain how a protein is made, limited to: • the gene coding for the protein remains in the nucleus • messenger RNA (mRNA) is a copy of a gene • mRNA molecules are made in the nucleus and move to the cytoplasm • the mRNA passes through ribosomes • the ribosome assembles amino acids into protein molecules • the specific sequence of amino acids is determined by the sequence of bases in the mRNA (knowledge of the details of transcription or translation is not required)Syllabus objective17.1.9Most body cells in an organism contain• Explain that most body cells in an organism contain the same genes, but many genes in a particular cell are not expressed because the cell only makes the specific proteins it needsSyllabus objective17.1.10Haploid nucleus as a nucleus• Describe a haploid nucleus as a nucleus containing a single set of chromosomesSyllabus objective17.1.11Diploid nucleus as a nucleus• Describe a diploid nucleus as a nucleus containing two sets of chromosomesSyllabus objective17.1.12Diploid chromosome pairs• State that in a diploid cell, there is a pair of each type of chromosome and in a human diploid cell there are 23 pairsSyllabus objective