Author Capstone Axis

Transcription – Quick-Grasp Notes 🧬 1. Big Picture ✨ Transcription copies genetic info from one DNA strand into RNA. Complementary base-pairing still rules, but adenine now pairs with uracil (A–U). Unlike replication (which copies the whole DNA), transcription targets only one strand of a specific segment :contentReference[oaicite:0]{index=0}. 2. Why Use Only One DNA Strand? 🤔 […]

DNA Replication 🧬 Think of the double-helix as a clever zipper. When it “unzips,” each old strand guides the building of a brand-new partner strand. After the job is done, every daughter DNA holds one parental strand + one fresh strand. Scientists call this neat trick semiconservative replication.:contentReference[oaicite:0]{index=0} 1. Watson & Crick’s Big Hint 💡

1. Big Picture 🌍🧬 Scientists agree that RNA appeared before DNA and served as the very first genetic material. :contentReference[oaicite:0]{index=0} It didn’t just store information—it also sped up key reactions, acting like an enzyme. Because of this two-in-one role, researchers call the early stage of life the “RNA World.” :contentReference[oaicite:1]{index=1} 2. Why RNA Took the

🧬 The Search for Genetic Material 1. A Quick Historical Snapshot 📜 Mendel had linked heredity to “factors,” and by the early 1900s scientists knew these factors lived on chromosomes. But which molecule carried the instructions? This mystery drove the classic experiments below — each shining new light on life’s instruction manual. :contentReference[oaicite:0]{index=0} 2. Griffith’s

DNA 🧬 – The Cell’s Master Blueprint DNA (deoxyribonucleic acid) is a super-long chain of deoxyribonucleotides. Scientists measure its length by simply counting the nucleotides (or base pairs). For instance, the tiny bacteriophage φ×174 carries 5 386 nucleotides, whereas a single human gamete contains 3.3 × 109 bp! :contentReference[oaicite:0]{index=0} 1. Building a Polynucleotide Chain 🔗

Genetic Disorders 🧬 1. Pedigree Analysis 🧑‍🤝‍🧑 Geneticists draw a family tree (pedigree) to see how a trait travels through the generations. Squares stand for males, circles for females; a filled symbol marks someone who shows the trait. By reading the pattern you can spot whether the trait is dominant / recessive and whether it

Mutation 🧬 What is a mutation? A mutation happens when the DNA sequence changes, creating new versions of genes and, in turn, new traits in an organism. These changes, alongside recombination, add fresh variety to DNA and explain why individuals differ from each other. :contentReference[oaicite:0]{index=0} How do mutations occur? 🔄 One DNA strand in each

Sex Determination — How Chromosomes Decide 🌟 Why do some babies grow up to be boys and others girls? The secret lies in tiny packages of DNA called sex chromosomes. Let’s explore! 🔬🧬 :contentReference[oaicite:0]{index=0} 1. Early Clues Henking’s discovery (1891): He noticed an “X body” during insect sperm formation; only half the sperm had it.

Pleiotropy 🧬 – One Gene, Many Faces Sometimes a single gene can shape several visible traits in an organism. Genes with this super-power are called pleiotropic genes. When a pleiotropic gene changes, different body features change together because the gene influences shared metabolic pathways that branch out to many traits.:contentReference[oaicite:0]{index=0} How It Works 🔄 One

Polygenic Inheritance 🌈 Some traits don’t fit neatly into “either–or” boxes. Instead of just purple vs. white flowers or tall vs. short people, we see a smooth spread of possibilities—think of all the different human heights you notice every day. These smoothly varying traits are usually polygenic, meaning they’re guided by three or more genes