Structures and organisms

• Organelles


  Specialised subcellular structures found within living cells.
• Cells


  Basic structural unit of a living organism.
• Tissues


  Group of cells with similar structures, working together to perform the same function.
• Organs


  Group of tissues, working together to perform specific functions.
• Organ systems


  Group of organs with similar functions, working together to perform body functions.
• Nucleus


  Contains the genetic material, which codes for a particular protein, enclosed in a nuclear membrane.
• Cytoplasm


  Liquid substance in which chemical reactions occur, containing enzymes and organelles.
• Cell membrane


  Contains receptor molecules to identify and selectively control what enters and leaves the cell.
• Mitochondria


  Where aerobic respiration reactions occur, providing energy for the cell.
• Ribosomes


  Where protein synthesis occurs, found on the rough endoplasmic reticulum.
• Chloroplasts


  Where photosynthesis takes place, providing food for the plant, containing chlorophyll pigment.
• Permanent vacuole


  Contains cell sap, found within the cytoplasm, improves cell's rigidity.
• Cell wall


  Made from cellulose, provides strength to the cell.
• Specialised cells


  Cells that have developed certain characteristics to perform particular functions.
• Differentiation


  Process that involves the cell gaining new sub-cellular structures suited to its role.
• Stem cells


  Undifferentiated cells which can undergo division to produce many more similar cells.
• Sperm cells


  Specialised to carry the male's DNA to the egg cell for successful reproduction.
• Nerve cells


  Specialised to transmit electrical signals quickly from one place in the body to another.
• Muscle cells


  Specialised to contract quickly to move bones or squeeze, causing movement.
• Root hair cells


  Specialised to take up water by osmosis and mineral ions by active transport from the soil.
• Xylem cells


  Specialised to transport water and mineral ions up the plant from the roots to the shoots.
• Phloem cells


  Specialised to carry the products of photosynthesis to all parts of the plants.
• Embryonic stem cells


  Form when an egg and sperm cell fuse to form a zygote, can differentiate into any type of cell.
• Adult stem cells


  Found in bone marrow, can form many types of cells but not any type like embryonic stem cells.
• Meristems in plants


  Found in root and shoot tips, can differentiate into any type of plant throughout the life of the plant.
• Carbohydrates


  Made of carbon, oxygen and hydrogen, polymers that break down into simple sugars.
• Proteins


  Made of carbon, oxygen, hydrogen, sulfur, nitrogen and phosphorous, polymers broken down into amino acids.
• Lipids


  Made of carbon, oxygen and hydrogen, large polymers broken down into 3 fatty acids and a glycerol molecule.
• Glucose Test


  Uses Benedict's solution to detect glucose presence.
• Benedict's Solution


  Reagent that turns brick red in glucose presence.
• Starch Test


  Uses iodine solution to identify starch presence.
• Iodine Solution


  Turns blue-black when starch is present.
• Protein Test


  Uses Biuret solution to detect protein presence.
• Biuret Solution


  Turns purple in the presence of protein.
• Fat Test


  Uses ethanol and distilled water to detect fat.
• Milky White Emulsion


  Indicates fat presence in a solution.
• Enzymes


  Biological catalysts that speed up reactions.
• Active Site


  Region where substrate binds on an enzyme.
• Lock and Key Hypothesis


  Describes enzyme specificity based on shape.
• Optimum Temperature


  Ideal temperature for enzyme activity, around 37°C.