Biology Paper 1

• What are the two types of cells? Eukaryotic (plants and animals) Prokaryotic (bacteria)
• What are the differences between a eukaryotic and prokaryotic cells? Prokaryotic cells are much smaller than eukaryotic cells. Eukaryotic cells contain membrane bound-organelles and a nucleus containing genetic material, while prokaryotic don't.
• What is the prokaryotic cell wall composed of? Peptidoglycan
• How is genetic information stored in a prokaryotic cell? Found free within the cytoplasm as: - Chromosomal DNA (single large loop circular DNA) - Plasmid DNA
• What are plasmids? Small, circular loops of DNA found free in the cytoplasm and separate from the main DNA. They also carry genes that provide genetic advantages e.g. antibiotic resistance.
• List the components of both plant and animal cells. - Nucleus - Cell Membrane - Cytoplasm - Mitochondria - Ribosome
• List all additional components found in plant cells. - Chloroplast - Cell Wall - Permanent vacuole
• Other than storing the genetic information, what is the function of the nucleus? Controls cellular activities.
• Describe the structure of the cytoplasm. - Fluid components of the cell. - Contains organelles, enzymes and dissolved ions and nutrients.
• What is the formula for magnification? Magnification = Size of image/Real size of image
• What are chromosomes? Chromosomes carry genetic information in a molecule called DNA
• How many chromosomes does each human body have? 46 chromosomes arranged into 23 pairs
• What are female chromosomes referred to as? XX
• What are male chromosomes referred to as? XY
• When do cells divide? - When an organism grows - When an organism gets damaged
• What does the first stage of the cell cycle involve? The first stage of the cell cycle involve cell growth, then synthesis of DNA.
• What is mitosis? Mitosis is when two daughter cells are produced, each identical to the parent cell.
• What are stem cells? Stem cells are cells that have not undergone differentiation.
• What can a embryonic stem cells differentiate to? Any cell type
• Where can you find adult stem cells? - Brain - Eyes - Blood - Heat - Liver - Bone Marrow - Skin - Muscle
• Can adult stem cells differentiate into any cell? No. Differentiation for adult stem cells is very limited.
• Where does cell division happen in plants? Meristems
• Can cells of the meristem differentiate to produce all types of plant cells at any time during the life of the plant? Yes
• Where can you find the main meristems? - At the tip of the shoot - At the tip of the root
• What are the Palisade mesophyll cells specialised to do? Carry out photosynthesis
• What are Phloem cells specialised to do? Transport products of photosynthesis including sugars and amino acids, from the leaf to where they are needed.
• What are Xylem cells specialised to do? Transport water and dissolved minerals from the roots, up the plant.
• What are Meristem cells specialised to do? Produce new cells as they divide
• Why are stem cells useful? Stem cells are useful because they can be transplanted into patients to treat medical conditions and diseases. They could be used to replace cells that have been damaged or destroyed.
• Why are people against using embryonic stem cells? They may believe everyone has the right to live, and may have ethical and religious obligations against it.
• What can bone marrow stem cells be used to treat? - Leukaemia and Lymphoma - When blood cells have been destroyed by cancer treatment.
• Why do patient's use their own stem cells? [2] - Genetically identical so it won't not be rejected by the patient's immune system - Adults can give consent
• What is Therapeutic cloning? Therapeutic cloning produce stem cells with the same genetic make-up as the patient.
• What are the benefits with using stem cells? It allows doctors to treat patients with untreatable conditions, growing organs for transplants and research.
• What are the disadvantages associated with the use of stem cells in medicine? [2] - There is no guarantee how successful these therapies will be. - There is difficulty in finding suitable stem cell donors.
• What is diffusion? Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration.
• Give an example of diffusion in the human body. An example of diffusion within the human body is the exchange of Oxygen and Carbon Dioxide in the lungs.
• What is a solute? A solute is the substance that dissolves to make a solution.
• What is a solvent? A solvent is the substance that does the dissolving – it dissolves the solute.
• What 3 factors can affect the rate of diffusion? - Concentration Gradient - Temperature - Surface area of the cell membrane separating the different regions