Genetics

Label the Structures Word Bank: Nucleus, DNA, Cell, DNA, Chromosome, DNA, Gene, Genes Cell Nucleus Chromosome DNA DNA Gene Genes DNA Matching Replication Copying DNA Genome All the DNA for an organism Genes Sections of DNA Deoxyribonucleic acid Genetic molecule in a double helix Nucleotide A nitrogen base, sugar and phosphate Chromosome Packed up DNA Literacy Article for Basic Genetics After trying the answers above, use this literacy article to help you check and correct your answers.Genes, DNA and our health are always in the news. This section will help it all make sense.We all began life as a single cell. It was your genes that guided that cell to divide in two, and then into four and so on until you developed all the tissues, organs, and systems that make you.But the role your genes play in shaping who you are doesn’t end at birth.Your genes are constantly interacting with the environment around you. They influence everything from your health to your appearance, your behavior and your personality.Chromosomes, genes and DNAInside almost every one of the 38 trillion or so cells that our bodies contain is a tiny organelle called the nucleus which acts like the control center of the cell. The nucleus carries the instructions as DNA code packed into chromosomes.ChromosomesInside the nucleus of a human cell are 46 chromosomes—the complete genome for humans. Each one is made up of a strand of DNA (deoxyribonucleic acid) – an incredibly long molecule which carries the code for all your genetic information.It's estimated that if a strand of DNA was stretched out, it would be around three meters long, even though the average cell is smaller than a pinhead.Chromosomes are inherited in pairs: 23 from your mother and 23 from your father. Before cells divide chromosomes make identical copies of themselves--which is why they’re often shown as ‘X’-shape. Making an exact copy of DNA is called DNA replication.GenesThe strand of DNA which makes up each of your chromosomes is arranged into sections called genes which are coded instructions for making proteins. Proteins carry out most of the work of cells to perform life functions.Almost every cell in your body (with the exception of red blood, egg and sperm cells) contains a complete set of around 25,000 genes – known as your genome.But the cell only uses the genes it needs to carry out its role. For example, a heart cell will use different genes than a lung cell or a nerve cell.DNADNA (deoxyribonucleic acid) is a very long double-stranded molecule, tightly coiled into a ‘double helix’ shape which looks like a twisted ladder. Nitrogen molecules called nucleotides (a nitrogen base, sugar and phosphate) make up DNA. The sugar and phosphate molecules on the sides of the DNA molecule are always the same for all living things, so when scientists write out the DNA code, they write only the sequence of the pairs of nitrogenous bases in the center (i.e., on the rungs) of the ladder-like DNA molecule. The ‘rungs’ of the ladder are made up of pairs of interlocking bases. The first letters A (adenine), T (thymine), C (cytosine) and G (guanine) are used to represent the bases. Nucleotides form bonds to hold the nucleic acids together. ‘A’ always pairs up with ‘T’, and ‘C’ with ‘G’.These letters spell out three letter ‘words’, called codons, which in turn form sentences, or ‘genes’. So a ‘gene’ is a sequence of nucleotides (ATTCAGCGA etc.) which encodes the instructions for making proteins – the building blocks for everything that makes you YOU!