Blog topic
Biology articles
The largest archive: photosynthesis, DNA copying, natural selection, the immune system, kidneys, circulation, neurons, cells and genetics. Each article follows one process from start to finish, so the vocabulary arrives attached to a job rather than as a list.
56 explainers, newest first. Each one ends with real questions from the unit that teaches it, so you can read the explanation and then check whether it stuck.
These are the readable companion to the Biology track, which holds 18 units and 2,067 practice questions. If you are starting the subject rather than looking something up, the study guide is the better place to begin.
What Is Diabetes? Sugar, Insulin and the Two Diseases That Share a Name
Diabetes is the failure to control blood sugar, because the body has stopped making insulin or responding to it. The two types, the damage, and the treatments.
September 15, 20265 min readWhat Are Fungi? Neither Plant Nor Animal, and Closer to Us Than to Trees
Fungi are a kingdom of their own: organisms that digest food outside their bodies and grow as networks of threads. What a mushroom is, and what fungi do for us.
September 15, 20264 min readWhat Is Cholesterol? The Molecule Every Cell Needs and Every Artery Fears
Cholesterol is a fat the body makes and cannot do without, carried by particles whose balance sets the risk of heart disease. What the numbers mean.
September 15, 20265 min readWhy Do We Get a Fever? The Body Turning Up Its Own Thermostat
A fever is not the infection overheating the body but the brain raising its set point on purpose. What triggers it, why heat helps, and when to bring it down.
September 15, 20264 min readWhat Are Parasites? Life at Someone Else's Expense
A parasite lives on or in another organism and feeds on it without killing it outright. The main kinds, how some steer their hosts, and why they are so many.
September 15, 20265 min readHow Does Alcohol Affect the Body? From the First Sip to the Hangover
Alcohol is a small molecule that reaches every organ in minutes and is cleared by the liver at a fixed rate. What it does to the brain, and what a hangover is.
September 15, 20265 min readWhat Happens in the Brain When You Sleep?
Sleep is not the brain switching off. It cycles through distinct stages every ninety minutes, files the day's memories, clears waste and.
September 14, 20265 min readWhy Do We Have Blood Types? A, B, O and the Rhesus Factor Explained
Blood types are sugars on the surface of red cells and the antibodies that attack the ones you lack.
September 14, 20265 min readHow Do Antibiotics Work, and Why Do Bacteria Stop Responding?
Antibiotics attack structures bacteria have and human cells do not. What the main kinds target, why they fail against viruses, and how resistance spreads.
September 14, 20265 min readWhat Is a Virus? A Particle That Runs on Borrowed Cells
A virus is a package of genes in a protein coat with no metabolism of its own. How it hijacks a cell, why it is hard to call alive, and where viruses came from.
September 14, 20265 min readHow Does Caffeine Work? The Molecule That Blocks Sleepiness
Caffeine keeps you awake by jamming the receptor that tells the brain it is tired. How it works, how long it lasts, and why the effect fades with habit.
September 14, 20265 min readWhat Are Vitamins? The Thirteen Molecules the Body Cannot Make
Vitamins are small organic compounds the body needs in tiny amounts and cannot make itself. What each does, how they were discovered, and whether pills help.
September 14, 20264 min readWhat Is Cancer? When a Cell Stops Obeying the Rules
Cancer is a cell's own descendants growing without limit after mutations disable the brakes on division. How it starts, why it spreads, and how it is treated.
September 14, 20265 min readHow to Use Punnett Squares to Predict Genetic Traits
Learn how to use Punnett squares to predict possible offspring genotypes and phenotypes, with simple steps for alleles, crosses, and probability.
August 17, 20266 min readWhat Is a Biome? Climate, Plants, Animals, and Large Ecosystems
Learn how climate, vegetation, soils, and living communities shape major regions such as deserts, grasslands, forests, and tundra.
August 17, 20266 min readWhat Are Stem Cells? How They Grow, Divide, and Specialise
Learn how these unusual cells can make more stem cells, become specialised cells, and support growth, repair, and research.
August 17, 20265 min readWhat Is an Ecosystem? Living Things and Their Environment
Learn how organisms interact with each other and with nonliving factors such as water, soil, light, temperature, and nutrients.
August 17, 20265 min readWhat Is Apoptosis? How Programmed Cell Death Protects the Body
Learn how programmed cell death removes damaged or unneeded cells and helps tissues develop, renew, stay balanced, and protected.
August 17, 20265 min readHow Do Reflex Arcs Work? From Stimulus to Rapid Response
Learn how receptors, sensory neurons, the spinal cord, motor neurons, and effectors produce fast automatic responses.
August 17, 20265 min readWhat Is the Lymphatic System? A Simple Biology Guide
Learn what the lymphatic system is, how lymph vessels and nodes move fluid, support immune defences, and help return excess tissue fluid to the bloodstream.
August 17, 20265 min readWhat Is the Endocrine System? A Simple Guide to Hormones
Learn how glands and hormones coordinate growth, metabolism, stress, reproduction, and other body functions clearly.
August 14, 20265 min readWhat Is a Chromosome? DNA Packaging Explained Simply
Learn how DNA wraps around proteins, how chromosomes carry genes, and why their number and shape matter during cell division.
August 14, 20265 min readHow Do Vaccines Work? A Simple Biology Guide
Learn how immune memory develops, why antigens matter, and how vaccination helps your body respond faster to later infections.
August 14, 20265 min readWhat Is Diffusion in Biology? How Particles Move
Learn how particles move down a concentration gradient and why diffusion matters in cells, lungs, leaves, and tissues.
August 14, 20265 min readDominant and Recessive Alleles: What the Terms Really Mean
Dominant and recessive alleles describe how gene variants affect a trait in a heterozygote. Learn genotype, phenotype, and common genetics mistakes.
August 14, 20266 min readWhat Is a Gene? How DNA Instructions Help Cells Work
Learn how genes are sections of DNA, how they help make functional products, and how different gene versions can affect traits.
August 14, 20266 min readWhat Is Cell Differentiation? How Cells Become Specialised
Learn how cells with the same DNA become specialised, how gene activity changes, and why differentiation matters.
August 14, 20266 min readHow Transpiration Works: How Water Moves Through a Plant
How transpiration works becomes clear when you follow water from roots to leaves. Learn about xylem, stomata, evaporation, and environmental factors.
August 14, 20266 min readWhat Is Protein Synthesis? How Cells Build Proteins
Follow transcription, mRNA, ribosomes, and translation to see how cells turn genetic instructions into useful proteins.
August 14, 20266 min readWhat Is a Genetic Mutation? How DNA Changes Can Affect Traits
Learn how DNA changes happen, the main mutation types, and why their effects can be harmful, helpful, or neutral.
August 14, 20266 min readWhat Is Mitosis? Cell Division Explained Simply
Learn how one cell separates copied chromosomes into two nuclei and why mitosis matters for growth, repair, and cell replacement.
August 13, 20265 min readHow the Digestive System Works from Mouth to Intestine
Learn how the digestive system works as food is broken down, nutrients are absorbed, and waste moves through the body from mouth to large intestine.
August 13, 20265 min readParts of a Plant Cell: What Each Structure Does
Learn the parts of a plant cell, what each structure does, and how the nucleus, chloroplasts, vacuole, membrane, and cell wall work together.
August 13, 20265 min readHow Symbiosis Connects Different Species
Symbiosis describes close relationships between different species. Mutualism, commensalism and parasitism show that living things can help, ignore or harm one another while sharing the same ecosystem.
August 8, 20265 min readHow the Liver Processes Nutrients and Waste
The liver receives nutrient-rich blood from the digestive system and performs many chemical jobs. It stores fuel, processes amino acids, makes important proteins and helps remove harmful substances.
August 8, 20265 min readHow Homeostasis Keeps Body Temperature Stable
Your body works best within a narrow temperature range. Homeostasis uses sensors, the brain and effectors such as skin blood vessels and sweat glands to keep internal temperature close to a useful level.
August 8, 20265 min readHow Bacteria Grow and Reproduce
Most bacteria reproduce by binary fission, a simple process in which one cell copies its DNA and divides into two. Growth depends on nutrients, temperature, water and other environmental conditions.
August 8, 20265 min readHow Bones and Joints Create Movement
Bones provide support, joints allow movement and muscles pull on the skeleton through tendons. Understanding how these parts work together makes everyday actions easier to explain.
August 5, 20265 min readHow Meiosis Creates Genetic Variety
Meiosis makes sex cells with half the usual number of chromosomes. Shuffling and separating genetic material during the process helps produce variation between offspring.
August 4, 20265 min readHow Plant Tropisms Guide Growth
Plants cannot walk towards light or water, but they can change how they grow. Tropisms are directional growth responses that help roots and shoots reach useful conditions.
August 4, 20265 min readHow Osmosis Moves Water Through Cells
Osmosis is the movement of water across a partially permeable membrane. It helps cells control their water balance and explains why plant and animal cells respond differently to dilute and concentrated surroundings.
July 29, 20265 min readHow Pollination Helps Flowering Plants Make Seeds
Pollination moves pollen to the female part of a flower. It begins a sequence that can lead to fertilisation, seed formation and the growth of fruit.
July 29, 20265 min readHow Enzymes Speed Up the Reactions of Life
Enzymes are biological catalysts that help cell reactions happen quickly enough to support life. Their shape, temperature and surroundings affect how well they work.
July 29, 20265 min readHow Your Lungs Exchange Oxygen and Carbon Dioxide
Your lungs move oxygen into the blood and carbon dioxide out of it. Tiny air sacs, thin surfaces and constant blood flow make this rapid exchange possible.
July 29, 20265 min readHow Neurons Send Messages Through Your Body
Neurons carry information using electrical changes and chemical signals. Following one message from start to finish makes the nervous system much easier to understand.
July 26, 20265 min readHow Muscles Turn Signals into Movement
Muscles move when nerve signals release calcium inside muscle fibres. Calcium, actin, myosin and ATP then work together in a repeating cycle that shortens the muscle.
July 26, 20265 min readHow Antibodies Help Defend Your Body
Antibodies are proteins that recognise particular targets and help the immune system respond. Their shape, memory and teamwork make later encounters with the same threat easier to handle.
July 26, 20265 min readHow Cellular Respiration Releases Energy from Food
Cellular respiration transfers energy from glucose into ATP, a form cells can use. The process happens through several stages rather than one sudden burst.
July 26, 20265 min readHow Photosynthesis Feeds the World
Photosynthesis is how plants turn light into stored food. Follow the journey from sunlight to sugar, and see why nearly every food chain begins with a green leaf.
July 24, 20265 min readFood Webs Show How Ecosystems Connect
A food chain follows one route through an ecosystem, but real feeding relationships form a web. That web helps explain both stability and sudden change.
July 24, 20265 min readHow Your Body Blocks Germs Before You Feel Sick
Your immune system does not wait politely for an infection to settle in. Skin, mucus, fast-acting cells, and inflammation form layers of defence that begin working immediately.
July 24, 20265 min readHow DNA Copies Itself Before a Cell Divides
Before a cell can divide, it must make a careful copy of its DNA. The process uses matching base pairs, helper enzymes and several rounds of checking.
July 24, 20265 min readHow Your Kidneys Keep Water and Salts in Balance
Your kidneys filter blood, return useful materials and adjust how much water leaves your body. This steady balancing act is a clear example of homeostasis.
July 24, 20265 min readHow Blood Circulation Keeps Your Body Supplied
Your heart, lungs and blood vessels form two connected loops. Together they deliver oxygen and nutrients, carry away wastes and help every part of your body keep working.
July 24, 20265 min readHow Natural Selection Changes Populations Over Time
Natural selection happens when inherited differences affect survival and reproduction. Over many generations, helpful traits can become more common in a population.
July 24, 20265 min readA Gentle Beginner's Guide to Learning Biology
Biology can feel like a mountain of long words. Start small, follow the story of life, and it becomes one of the most rewarding subjects there is.
July 9, 20266 min read