Biology Paper 1

• What are eukaryotic and prokaryotic cells?

  A eukaryotic cell: a complex cell (e.g. a plant or animal cell)

  A prokaryotic cell: a small, simple cell
• What is the purpose of the fine adjustment knob on a light microscope?

  It is used to focus the lens until a clear image of what’s on the slide appears
• In which sub-cellular structures do most of the reactions of aerobic respiration take place?

  Mitochondria
• Do electron microscopes have a higher or smaller magnification and resolution than light microscopes?

  Electron microscopes have a higher magnification and resolution than light microscopes
• What does resolution mean?

  The ability to distinguish between two points
• Which cells in plants are specialised for absorbing water and minerals from the soil?

  Root hair cells
• What is the function of a sperm cell?

  To transport male DNA to the female DNA in eggs for reproduction
• In human body cells, are chromosomes normally found in pairs or triplets?

  In pairs (one comes from the mother and one from the father)
• What do chromosomes contain?

  Genes: chromosomes are coiled up in lengths of DNA, which carry a large number of genes
• What is Mitosis? What is it used for?

  Mitosis is the stage of the cell cycle when the cell divides; organisms use mitosis to grow or replace cells that have been damaged
• What is a stem cell?

  A stem cell is an undifferentiated cell which has the ability to become one of many different types of cell or more stem cells
• What type of plant tissue contains stem cells?

  Meristem tissue (this is where growth occurs)
• Where can stem cells be found in an adult human? What do they do?

  Bone Marrow; they turn into specific cells, such as blood cells
• Name a gas molecule that can diffuse through cell membranes.

  Oxygen and carbon dioxide
• What type of membrane is needed for osmosis to happen?

  A partially permeable membrane (it has holes in it, so tiny molecules can pass through)
• What is active transport?

  The movement of substances from a lower concentration to a higher concentration, using energy from respiration
• How does the size of an organism affect its surface area to volume ratio?

  The larger an organism is, the smaller its surface area to volume ratio
• Can single celled organisms with a large surface area to volume ratio easily exchange substances with the environment, without adaptions?

  Yes; enough substances can be exchanged across their cell membrane to supply the needs of the cell
• Name three gases that are exchanged in a leaf.

  Oxygen, water vapour and carbon dioxide
• What is the function of the alveoli?

  Alveoli allows the efficient/rapid transfer of oxygen to the blood and the removal of waste carbon dioxide from the blood
• How does the concentration gradient affect the rate of diffusion?

  The bigger the concentration gradient, the faster the rate of diffusion
• What is a group of organs working together to perform a particular function called?

  An organ system
• How do enzymes affect the rate of a reaction?

  Enzymes increase the rate of reaction
• What is an active site of an enzyme?

  The active site is the part of the enzyme that substrate fits into
• Which type of molecule is broken down into amino acids?

  Proteins are broken down into amino acids
• What are the products of lipid digestion?

  Glycerol and fatty acids
• What type of food molecule can be identified in a sample using the Benedict’s test?

  Sugars
• What is the iodine test used to test for?

  Starch
• Name the structures in the lungs where gas exchange takes place.

  Alveoli (there are millions of these tiny air sacs in the lungs)
• Name the structure that changes the surface area of the lungs during breathing.

  The diaphragm
• Name the blood vessel which carries blood into the right atrium of the heart.

  Vena Cava
• Which side of the heart pumps deoxygenated blood to the lungs?

  The right side of the heart
• What is the function of white blood cells?

  White blood cells defend the body against infection
• What is plasma?

  Plasma is the liquid that carries everything in blood
• What is a stent?

  A stent is a tube that is inserted inside an artery
• How do stents reduce the risk of heart attacks?

  Stents keep coronary arteries open, so oxygenated blood can flow to the heart muscle
• How do statins help to treat cardiovascular disease?

  Statins reduce cholesterol in the blood, slowing down the rate of fatty deposit formation
• True or false? Communicable diseases can be spread between people, or between animals and people.

  True; communicable diseases are contagious
• Give two examples of non-communicable diseases.

  Asthma and cancer
• What is meant by the term ’carcinogen’?

  Something that causes cancer