Genetics

DNA and Genes

• Know that deoxyribonucleic acid (DNA) is a molecule found in the nucleus of our cells

• Know that DNA stores coded instructions for the production of proteins

• Know the basic structural components of DNA is are nucleotides (each contains one of four bases (A, T, C, G) a phosphate and sugar)

• Know that the bases are specific (Adenine always binds with Thymine and Cytosine binds with Guanine)   

• Know that a section of DNA that codes for a specific protein is called a gene 

• Know that DNA carries the code that specifies the structure and function of cells  

• Understand that different genes are responsible for different characteristics

• Know that human body cells contain 23 pairs or 46 chromosomes – threadlike structures  containing many genes

• Know that mitosis is used in the growth and repair of new body cells, while meiosis is used in the production of sex cells (sperm and ova)

• Know the processes by which mitosis produces diploid cells and meiosis produces haploid cells

• Identify and describe the stages of mitosis: prophase, metaphase, anaphase, telophase

Variation 

• Understand that the similarities and differences in how you look compared to your relatives is due to chance

• Know some characteristics that are inherited (eye colour, widows’ peak, some personality traits)

• Know that the alternative forms or expressions of a gene are called alleles – for example, blue, brown, green etc. are different alleles for the eye colour gene

• Understand the environment can impact on gene expression

Genotypes and Phenotypes  

• Know that in complete dominance, there are dominant and recessive traits

• Understand that if one allele is dominant to the other, it will always be expressed or shown, where as a recessive allele is only expressed or shown then the dominant allele is not present

• Understand that the combination of the letters described above is called a genotype – for example BB

• Know that the actual appearance of how the trait is expressed is called the phenotype – for example, blue eyes or brown eyes

• Know that if the two alleles for a particular trait are the same – for example, BB or bb – the individual is said to be pure breeding or homozygous for that trait

• Know that if the two alleles for a particular trait are different – for example, Bb – the individual is said to be a hybrid or heterozygous for that trait

• Know that the term carrier refers to someone who is heterozygous and carries the recessive allele for a particular trait

Punnett squares

• Know that possible combinations of gametes with particular alleles can be shown in a grid called a Punnett square (monohybrid cross)

• Be able to draw up Punnett squares and calculate the chances (ratio and percentage) of possible combinations

Changes to genes

• Know that uneven sharing of chromosomes and other chromosomal errors can occur during cell division and that changes to genes and chromosomes are called mutations

• Know that inherited gene and chromosomal abnormalities result in genetic disorders. These can be identified in a karyotype analysis

• Know that pedigrees are a useful tool for tracking genetic disorders in a family over a series of generations 

Biotechnology

• Provide examples of biotechnology

• Describe advantages and disadvantages of biotechnology

• Describe some social and ethical considerations related to the use of biotechnology