AQA Biology Study Notes

Definition: A group of specialised cells with a similar structure and function.
Terms: Organism, system, tissue, organ.
Definition: Site of protein synthesis is the Ribosomes.
Options: Mitochondria, Lysosomes, Golgi Apparatus.
Definition: Cells on the surface of plant roots that grow into long "hairs" to stick out into the soil contribute to a larger surface area for absorbing water and minerals.
Term: Root hair cells.
Definition: A membrane that allows the free diffusion of some small solute molecules but not others is referred to as a Partially permeable membrane.

Definition: The organ system where food is digested and absorbed is known as the Digestive system.
Definition: The large blood vessel that takes deoxygenated blood from the right ventricle of the heart to the lungs is the Pulmonary artery.
Definition: Produces and secretes chemicals like enzymes and hormones is the Glandular tissue.

Definition: The non-living transport tissue in plants that transports water from the roots to the leaves and shoots is called Xylem.
  - Characteristics:
    - One-way only.
    - Has thick, stiffened walls with lignin.
Definition: The vascular tissue through which food moves in some plants is called Phloem.

Definition: The process by which plants make food using carbon dioxide, water, and light is called Photosynthesis.
Definition: The breakdown of molecular structure of a protein so it no longer functions is termed as Denaturation.

Definition: Enzymes that speed up the digestion of starch into sugars is Amylase.
Definition: Molecules that contain carbon, hydrogen, oxygen, and nitrogen and are made of long chains of amino acids used for building cells and tissues and forming enzymes are Proteins.
Definition: The breakdown of glucose in the absence of oxygen to produce lactic acid in animals or ethanol and carbon dioxide in plants and yeast is referred to as Anaerobic respiration.

Definition: Agents that cause cancer or significantly increase the risk of developing cancer are called Carcinogens.
Definition: A growth of abnormal cells that are contained and do not invade other tissues is known as Benign tumours.
Definition: The end product of anaerobic respiration in animal cells is Lactic acid.
Definition: Disease caused by pathogens that can be passed from one organism to another is known as a Communicable disease.
Definition: A medicine that does not contain the active drug being tested, used in clinical trials of new medicines is termed a Placebo.

Definition: Biological catalysts that usually are proteins are termed as Enzymes.
Definition: The smallest blood vessels are Capillaries.
- Function: They enable the exchange between blood and cells.
Definition: The clear yellow-liquid part of the blood that carries dissolved substances and blood cells is known as Plasma.

Definition: A change in the genetic material of an organism is called a Mutation.
Definition: The part of the cell cycle where one set of new chromosomes is pulled to each end of the cell forming two identical nuclei during cell division is called Mitosis.
Definition: Stem cells from an early embryo that can differentiate to form the specialised cells of the body are referred to as Embryonic stem cells.

Definition: The movement of sugars from the leaves to the rest of the plant through the phloem is termed Translocation.
Definition: The loss of water vapor from the leaves of plants through the stomata during gas exchange is referred to as Transpiration.
Definition: The upper layer of mesophyll tissue in plant leaves is called the Palisade mesophyll, made of closely packed cells with chloroplasts for photosynthesis.

Definition: Energy source for photosynthesis is referred to as Light.
Definition: The term for carbohydrate stored in animals is Glycogen.
Definition: A small carbohydrate unit such as glucose is called Simple sugars.

Definition: Blood vessels that carry blood away from the heart are known as Arteries.
- Characteristic: They usually carry oxygenated blood and have a pulse.
Definition: Blood cells involved in the immune response by engulfing pathogens are classified as White blood cells.

Definition: The responses to exercise include heart rate increase, breathing rate increase, and glycogen in muscles being converted to glucose.
Definition: The extra oxygen that must be taken into the body after exercise to complete lactate breakdown is termed Oxygen debt.
Definition: It involves taking in oxygen and releasing carbon dioxide, referred to as Gas exchange.
Definition: The part of the heart that receives deoxygenated blood from the body is the Right atrium.

Definition: The process of taking oxygen in and carbon dioxide out is known as Respiration.
Definition: The three-stage process of cell division resulting in two identical daughter cells is called the Cell cycle.