Learn: B1 You and Your Genes

Welcome!Today, we'll explore the fascinating topic of B1 You and Your Genes from the OCR Twenty First Century Science Biology B Specification. Let's learn how genetics shapes who we are!

What is the genome?A genome is the complete set of genetic material in an organism. It contains all the information needed for growth, development, and functioning. In humans, the genome is found in the nucleus of cells.

Where is genetic material found?In eukaryotic cells, genetic material is located in the nucleus. In prokaryotic cells, it is found in the cytoplasm as circular DNA and plasmids. This difference is key to understanding cell types.

What are chromosomes?Chromosomes are long DNA molecules that carry genes, which are sections of DNA responsible for specific traits. Humans have 23 pairs of chromosomes in each cell nucleus.

Understanding DNADNA (Deoxyribonucleic Acid) is a polymer made of nucleotides. It forms two strands twisted into a double helix. DNA contains the instructions for building and maintaining an organism, using a code made up of four bases: A, T, C, and G.

Alleles and GenesAn allele is a variant form of a gene. For example, the gene for eye colour can have alleles for blue, brown, or green eyes. The combination of alleles determines traits.

Protein synthesisProtein synthesis is the process of making proteins in cells. DNA provides the instructions, which are copied into mRNA (messenger RNA). The mRNA helps ribosomes build proteins using amino acids.

Mutations and Genetic VariantsMutations are changes to the DNA sequence. They are the source of genetic variants, which can affect an organism's traits. Some mutations are harmless, while others can lead to diseases.

Review Time!Great work! You've learned about genomes, DNA, chromosomes, alleles, protein synthesis, and mutations. Let's test your understanding with a few final questions.