Biology Paper 1

• Cells can be classified into two main types - prokaryotic (bacterial) and eukaryotic (plant/animal).
• Chloroplasts contain chlorophyll pigments which absorb light energy used in photosynthesis.
• Aorta: the main artery of the body, supplying oxygenated blood to the circulatory system. In humans it passes over the heart from the left ventricle and runs down in front of the backbone.
• Vena cava

  The main vein that takes deoxygenated blood back to the heart from the body
• Capillary

  A very thin blood vessel used for the exchange of substances
• Pulmonary Artery


  the main artery that takes deoxygenated blood away from the heart to the lungs
• Valves

  Found in veins and only allows the blood to flow in one direction
• Heart

  organ that pumps blood around the body in a double circulatory system
• vein

  a blood vessel that carries blood at a low pressure back to the hear
• Pulmonary Vein

  the main vein that takes oxygenated blood back from the heart to the lungs
• Blood

  a tissue containing red blood cells, white blood cells, platelets and plasma
• Artery

  A blood vessel that carries blood at a high pressure away from the heart
• what are red blood cells

  biconcave cells that have haemoglobin and carry oxygen
• Ethanol food test

  1 Add a few drops of ethanol to the food solution. 2 Shake the test tube and leave for one minute. 3 Pour the ethanol into a test tube of water. 4 If the solution turns cloudy, the food contains lipids.
• Iodine food test 1. Put some of the food sample into a test tube. 2. Add a few drops of iodine solution to the food sample using a pipette. 3. If starch is present, the solution turns from brown to blue-black. Note any colour change in a table of results
• carboyhydrase (amylase)


  an enzyme produced in the salivary glands and pancreas that breaks carbohydrates down into simple sugars
• lipase

  an enzyme that is produced in the pancreas that breaks down lipids into fatty acids and glycerol
• Protease


  an enzyme produced in the stomach and pancreas that breaks down proteins into amino acids
• Biuret Reagent

  1. Add a few drops of Biuret’s reagent (sodium hydroxide and copper (II) sulphate) to the food sample in a test tube. 2. Shake the solution to mix and wait for a few minutes. 3. If protein is present, the solution turns from blue to purple.
• Benedicts Reagent

  1. Add an equal volume or excess of Benedict’s solution to the food sample in a test tube. 2. Place in a hot water bath for a few minutes. 3. If reducing sugar is present, a brick red precipitate is formed. If reducing sugar is absent, the solution remains blue. Note any colour change in a table of results.
• Digestion

  the process of breaking down food
• Embryonic Stem cell

  A type of stem cell that can differentiate into most types of human cells
• fertilisation

  the action or process of fertilising an egg of a female animal or plant, involving the fusion of male and female gametes to form a zygote
• meristem 


  a type of stem cell that can differentiate into any type of plant cell
• stem cell

  an undifferentiated cell that can divide to produce many specialised cells of the same type
• Differentiation

  the process where a cell becomes specialised to its function
• ribosomes

  an organelle which has the function of protein synthesis
• bone marrow (adult stem cells)

  a type of stem cell that can form a limited number of cells, mostly the different components of blood
• Mitochondria

  an organelle in both animal and plant cells, the site of cellular respiration
• roots and shoots

  roots are anything below the ground and the shoots are anything above the ground. these 2 contain the meristems
• diffusion

  the random net movement of particles from an area of high concentration to an area of low concentration
• theraputic clone

  producing an embryo that has the same genes as a patient
• micrometre

  one millionth of a metre
• organelle

  a specialised structure found within a cell
• osmosis

  the random net movement of water particles from an area of high concentration to an area of low concentration across a partially permeable membrane
• active transport

  the movement of substances from a low concentration to a high cocentration (against a concentration gradient) with the use of energy from respiration
• Plasmid

  loops of DNA found in the cytoplasm of prokaryotic cells
• chromosomes

  DNA structures found in the nucleus made of genes
• Mitosis

  A stage in the cell cycle when the nucleus divides
• Cell cycle

  A series of stages in the life cycle of a cell