TEAS 7 Science Study Guide

Cardiovascular system

Blood flows from the body into the right atrium, through the right ventricle to the lungs, back to the left atrium, then out of the left ventricle to the body. The left ventricle is the thickest chamber because it pumps against systemic pressure.

Learn the circuit as a loop rather than a list. Most questions ask what comes next, not what a part is called.

Respiratory system

Air travels nose to pharynx, larynx, trachea, bronchi, bronchioles and alveoli, where gas exchange happens across a single cell layer. The diaphragm contracts and flattens to draw air in.

Inhalation is active and exhalation at rest is passive, driven by elastic recoil.

Nervous system

The central nervous system is the brain and spinal cord; the peripheral nervous system is everything else. The peripheral system divides into somatic voluntary control and autonomic involuntary control, which splits again into sympathetic and parasympathetic.

Sympathetic is fight or flight, parasympathetic is rest and digest. Expect at least one question distinguishing them.

Digestive system

Mechanical and chemical digestion run from mouth to oesophagus, stomach, small intestine and large intestine. Most absorption of nutrients happens in the small intestine; the large intestine reabsorbs water.

Skeletal system

Bone supports the body, protects organs, stores calcium and produces blood cells in red marrow. The axial skeleton is skull, spine and ribs; the appendicular skeleton is the limbs and girdles.

Muscular system

Skeletal muscle is voluntary and striated, cardiac muscle is involuntary and striated, and smooth muscle is involuntary and non-striated. Muscles pull rather than push, so they work in opposing pairs.

Endocrine system

Glands release hormones into the bloodstream to act on distant targets, which makes endocrine signalling slower and longer-lasting than nervous signalling. The pituitary directs several other glands.

Insulin lowers blood glucose and glucagon raises it. That pair appears more than any other.

Lymphatic and immune system

The lymphatic system returns fluid to the bloodstream and filters it through lymph nodes. Immunity is innate and non-specific or adaptive and specific, with the adaptive arm producing memory.

Integumentary system

Skin, hair and nails form the body's first barrier. Skin also regulates temperature through sweating and vessel dilation, and synthesises vitamin D. Its layers are epidermis, dermis and hypodermis.

Urinary system

Kidneys filter blood, balance fluid and electrolytes, and produce urine that passes through the ureters to the bladder and out via the urethra. The nephron is the functional unit.

Male and female reproductive system

Expect structures and their functions, gamete production, and the hormonal control of the menstrual cycle by oestrogen and progesterone.

Cell structure, function and organization

Mitochondria produce ATP, ribosomes build proteins, the nucleus holds DNA, and the Golgi packages material for transport. Prokaryotes have no nucleus or membrane-bound organelles; eukaryotes have both.

Plant cells add a cell wall and chloroplasts. Animal cells have neither.

Cell transport

Passive transport needs no energy and moves substances down a concentration gradient by diffusion or osmosis. Active transport uses ATP to move them against it.

Osmosis is specifically the movement of water. Cells swell in a hypotonic solution and shrink in a hypertonic one.

Genetics and DNA

DNA is a double helix in which A pairs with T and C with G. Genotype is the genetic makeup, phenotype the observable trait, and alleles can be dominant or recessive.

Mendel's law of inheritance

Mendel's laws of segregation and independent assortment underpin the Punnett square. A cross of two heterozygotes gives the familiar 3:1 phenotype and 1:2:1 genotype ratios.

Draw the square rather than reasoning it out. It takes fifteen seconds and removes the guesswork.

Structure and function of macromolecules

Carbohydrates supply quick energy, lipids store energy and build membranes, proteins do structural and enzymatic work, and nucleic acids carry genetic information. Each is built from its own monomer.

Role of microorganisms in disease

Bacteria, viruses, fungi and parasites cause disease by different mechanisms, which is why antibiotics treat bacterial infections and do nothing against viruses.

Atomic structure and the periodic table

Protons and neutrons sit in the nucleus and electrons orbit it. Atomic number is the proton count and defines the element; mass number is protons plus neutrons. Groups run down the table and periods across.

Chemical reactions and chemical bonding

Ionic bonds transfer electrons between a metal and a non-metal; covalent bonds share them between non-metals. Balanced equations must carry the same number of each atom on both sides.

Acids and bases

The pH scale runs 0 to 14, with 7 neutral. Acids donate hydrogen ions and sit below 7; bases accept them and sit above. Each whole step is a tenfold change in concentration.

Human arterial blood is held between 7.35 and 7.45, which is slightly alkaline. That range appears often.

Physical properties and states of matter

Solids, liquids and gases differ in particle arrangement and energy. Physical changes such as melting alter form only; chemical changes produce a new substance.

Scientific reasoning

This covers experimental design, variables, controls, hypotheses and evaluating evidence. A valid experiment changes one variable at a time and holds the rest constant.

The control group is the untreated comparison. Without it an experiment shows nothing, and questions often hinge on spotting its absence.