Human Biology Exam

What is a cell?

The basic structural and functional unit of life that carries out all essential life processes.

What is a tissue?

A group of similar cells working together to perform a specific function

What is an organ?

A structure made up of two or more tissue types that perform a specific function.

What is an organ system?

A group of organs working together to carry out a major body function

What is the hierarchy of organisation in the body?

Cells → Tissues → Organs → Organ Systems → Organism.

What is the cell membrane?

A selectively permeable barrier that controls movement of substances into and out of the cell.

What is the cytoplasm?

Jelly-like material where most cellular reactions occur.

What is the nucleus?

The control centre of the cell that contains DNA.

What are ribosomes?

Organelles that synthesise proteins.

What are mitochondria?

Organelles where aerobic respiration occurs and ATP is produced.

What is the rough ER?

Endoplasmic reticulum with ribosomes that modifies and transports proteins.

What is the smooth ER?

Endoplasmic reticulum involved in lipid synthesis and detoxification.

What is the Golgi body?

Modifies, packages and secretes proteins and lipids.

What are lysosomes?

Organelles containing digestive enzymes that break down waste and old cell structures.

What are centrioles?

Structures that help organise spindle fibres during cell division.

What is cellular respiration?

The process by which cells release energy from glucose to produce ATP.

What is ATP?

Adenosine triphosphate, the usable energy currency of cells.

Word equation for aerobic respiration?

Glucose + Oxygen → Carbon Dioxide + Water + Energy (ATP).

Chemical equation for aerobic respiration?

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy.

What is the fluid mosaic model?

A model describing the cell membrane as a phospholipid bilayer containing proteins that move freely.

What is diffusion?

Movement of particles from high concentration to low concentration without energy.

What is osmosis?

Movement of water across a selectively permeable membrane from high water concentration to low water concentration.

What is facilitated diffusion?

Passive movement through membrane proteins down a concentration gradient.

What is active transport?

Movement of substances against a concentration gradient using ATP.

What is endocytosis?

Uptake of materials into the cell using vesicles.

What is exocytosis?

Release of substances from the cell via vesicles.

What is epithelial tissue?

Tissue that covers body surfaces and lines organs and cavities.

What is connective tissue?

Tissue that supports, protects, binds and connects other tissues.

What is muscular tissue?

Tissue specialised for contraction and movement.

What is nervous tissue?

Tissue specialised for transmitting electrical impulses.

What is metabolism?

The sum of all chemical reactions occurring in a cell or organism.

What is an anabolic reaction?

A reaction that uses energy to build larger molecules from smaller ones.

What is a catabolic reaction?

A reaction that releases energy by breaking large molecules into smaller ones.

What is an enzyme?

A biological catalyst that lowers activation energy and speeds up chemical reactions.

What is a substrate?

The reactant upon which an enzyme acts.

What is an active site?

The region of an enzyme where the substrate binds.

What is the lock-and-key model?

A model where only a specific substrate fits a specific enzyme's active site.

What is denaturation?

Permanent alteration of an enzyme's shape causing loss of function.

What affects enzyme activity?

Temperature, pH, inhibitors, co-factors, co-enzymes and substrate concentration.

What is a carbohydrate?

An organic molecule containing C, H and O that is the body's main source of energy.

What is a protein?

A molecule made of amino acids used for structure, growth, repair and enzymes.

What is a lipid?

An energy-rich compound made of glycerol and fatty acids.

What is a vitamin?

An organic nutrient required in small amounts for normal metabolism.

What is a mineral?

An inorganic nutrient required for normal body functions.

What is the function of the respiratory system?

To exchange oxygen and carbon dioxide between the body and environment.

Pathway of air through the respiratory system?

Nose → Pharynx → Larynx → Trachea → Bronchi → Bronchioles → Alveoli.

What are alveoli?

Tiny air sacs where gas exchange occurs.

What is inspiration?

Breathing in as the diaphragm contracts and thoracic volume increases.

What is expiration?

Breathing out as the diaphragm relaxes and thoracic volume decreases.

Adaptations of alveoli?

Large surface area, thin walls, moist lining and rich blood supply.

What is the function of the circulatory system?

To transport substances around the body.

What is systole?

Contraction phase of the heart.

What is diastole?

Relaxation phase of the heart.

What is cardiac output?

The volume of blood pumped per minute.

Cardiac Output formula?

Cardiac Output = Heart Rate × Stroke Volume.

What is an artery?

A blood vessel carrying blood away from the heart.

What is a vein?

A blood vessel carrying blood toward the heart.

What is a capillary?

A microscopic vessel where exchange occurs between blood and tissues.

What is plasma?

Liquid portion of blood that transports dissolved substances.

What are erythrocytes?

Red blood cells that transport oxygen.

What are leucocytes?

White blood cells that defend against disease.

What are platelets?

Cell fragments involved in blood clotting.

What is phagocytosis?

The process where phagocytes engulf and destroy pathogens.

What is tissue fluid?

Fluid that surrounds cells and allows exchange of materials.

What is lymph?

Excess tissue fluid found within lymphatic vessels.

Function of the lymphatic system?

Returns excess tissue fluid to the bloodstream and helps defend against disease.

What is mechanical digestion?

Physical breakdown of food into smaller pieces.

What is chemical digestion?

Enzymatic breakdown of large molecules into smaller molecules.

What does amylase digest?

Carbohydrates.

What does protease digest?

Proteins.

What does lipase digest?

Lipids.

What is bile?

A substance that emulsifies fats to increase surface area for digestion.

What is peristalsis?

Wave-like muscle contractions that move food through the digestive tract.

Function of villi?

Increase surface area for nutrient absorption.

Function of microvilli?

Further increase absorptive surface area.

What is the sliding filament theory?

Muscle contraction occurs when actin and myosin filaments slide past each other.

What is a sarcomere?

The functional contractile unit of skeletal muscle.

Role of ATP in muscle contraction?

Provides energy for cross-bridge cycling and muscle movement.

What is an antagonistic muscle pair?

Two muscles that create opposite movements.

Example of an antagonistic pair?

Biceps and triceps.

What are the functions of the skeleton?

Support, protection, movement, mineral storage and blood cell production.

What is cartilage?

Flexible connective tissue that cushions joints and supports structures.

What is a tendon?

Connective tissue attaching muscle to bone.

What is a ligament?

Connective tissue attaching bone to bone.

What is osteoporosis?

A condition where bone density decreases, increasing fracture risk.

What is osteoarthritis?

Degeneration of joint cartilage causing pain and stiffness.

What is flexion?

Decreasing the angle at a joint.

What is extension?

Increasing the angle at a joint.

What is abduction?

Movement away from the body's midline.

What is adduction?

Movement toward the body's midline.

What is circumduction?

Circular movement of a limb.

What is excretion?

Removal of metabolic waste products from the body.

What is elimination?

Removal of undigested food from the digestive tract.

What is deamination?

Removal of the amino group from amino acids in the liver.

What is urea?

Nitrogenous waste produced by the liver and excreted by the kidneys.

Why is urea produced?

To safely remove toxic ammonia from the body.

What is a nephron?

The functional unit of the kidney that filters blood and forms urine.

Main function of the kidneys?

Remove wastes while regulating water and salt balance.

What is the ABO blood group system?

A blood classification system based on the presence of A and B antigens.

What is the Rh factor?

A blood antigen that determines whether blood is Rh positive or Rh negative.