unit 2

• Allele


  A form of a gene.

  
• Alveoli


  Tiny sacs in lungs that form the gas exchange surface.

  
• Anther


  Organ within a flower that produces pollen grains.

  
• Aorta


  Main artery that carries oxygenated blood away from the heart in mammals.

  
• Artery


  General name for a blood vessel that carries blood away from the heart.

  
• Atria


  Upper chambers of the heart, which receive the blood from veins.

  
• Brain


  Organ of the central nervous system of mammals where vital functions are coordinated.

  
• Capillaries


  Tiny blood vessels with walls one-cell thick where exchange of materials occurs.

  
• Cartilage


  Flexible tissue forming C-shaped rings in the trachea to keep the airway open.

  
• CNS


  Part of the nervous system made up of the brain and spinal cord.

  
• Cerebellum


  Part of the brain that controls balance and coordination of movement.

  
• Cerebrum


  Large folded part of the brain that controls conscious responses, memory, thought, intelligence and emotions.

  
• Cilia


  Hair-like structures lining the trachea that move mucus with trapped bacteria away from the lungs.

  
• Coronary


  Referring to the heart and blood vessels that serve the heart tissues.
• Digestion


  Breakdown of large, insoluble food molecules into smaller, soluble ones.

  
• discontinuous


  Alternative term for discrete variation
• Discrete


  Variation that is clear cut and observable as categories.
• Dominant


  Form of a gene that is expresses in the phenotype, whether homozygous or heterozygous.

  
• Endocrine gland


  Gland that produces and release a hormone directly into the blood.

  
• family tree


  Diagram that shows the inheritance of a genetic condition in a family.

  
• Fertilisation


  The fusion of gametes.

  
• Gamete


  Sex cell containing the haploid chromosome number.

  
• Genetic counselling


  Medical procedure in which individuals can receive advice and information about an inherited condition.
• Genotype


  The alleles that an organism has for a particular characteristic, usually written as symbols.

  
• Glucagon


  Hormone produced by the pancreas, responsible for triggering the conversion of glycogen into glucose in the liver.

  
• Glycogen


  Animal storage carbohydrate located in the liver and muscle tissues.

  
• Guard cells


  Found on either side of a stomata; they control gas exchange in leaves by controlling opening and closing of the stomata.

  
• Haemoglobin


  Pigment in red blood cells that transports oxygen as oxyhaemoglobin.

  
• Heart


  Muscular organ that pumps blood around the body.

  
• Heterozygous


  Describes a genotype in which the two alleles for the characteristic are different.

  
• Homozygous


  Describes a genotype in which the two alleles for the characteristic are the same.

  
• Insulin


  Hormone produced by the pancreas that triggers the conversion of glucose into glycogen in the liver.

  
• Lacteal


  Central vessel in the villi responsible for the absorption of fats.

  
• Lifestyle choice


  Decisions on lifestyle that impact on an individual's health.

  
• Lignin


  Carbohydrate material lining the xylem vessels and providing strength and support.

  
• Liver


  Large organ with many important functions including a role in blood glucose control.

  
• Lungs


  Organs responsible for gas exchange in mammals, birds, reptiles and amphibians.

  
• Lymph

  Liquid that circulates within a mammal's body, transporting the products of fat digestion from the lacteals.

  
• Medulla


  Part of the brain controlling breathing, heart rate and peristalsis.

  
• Meristem


  Localised region of actively dividing cells in plants.