biology

• What is the focus of AQA GCSE biology paper 1?

  Cells, organization, infection, and bioenergetics
• What types of biology does the AQA GCSE cover?

  Higher, foundation, double combined, and triple biology
• What can we see with a normal light microscope?

  Cells and possibly the nucleus
• What does an electron microscope allow us to see?

  Finer details of organelles
• How do we calculate the actual size of a cell?

  Image size divided by magnification
• What are the two main groups of cells?

  Eukaryotic and prokaryotic cells
• What do eukaryotic cells contain?

  A nucleus with DNA
• What do prokaryotic cells lack?

  A nucleus
• What is the function of the cell membrane?

  It keeps everything inside the cell
• What is a semi-permeable membrane?

  It allows certain substances to pass through
• What do plant cells and most bacteria have that provides structure?

  A cell wall made of cellulose
• What is cytoplasm?

  The liquid that makes up the cell
• Where does respiration take place in a cell?

  In the mitochondria
• What is the function of ribosomes?

  Where proteins are assembled
• What do chloroplasts contain?

  Chlorophyll for photosynthesis
• What is stored in the permanent vacuole of plant cells?

  Sap
• How do bacteria multiply?

  By binary fission
• What technique is used to produce a culture on agar?

  Aseptic technique
• Why do we lift the lid of the dish towards a flame?

  To move microbes away and destroy them
• What do we use to hold the lid on the petri dish?

  A few bits of tape
• What happens if the dish is sealed completely?

  Bacteria will respire anaerobically
• At what temperature do we incubate the culture?

  25 degrees Celsius
• How do we calculate the area of the culture?

  Using $\pi r^2$ or $\frac{\pi d^2}{4}$
• What do eukaryotic cell nuclei contain?

  DNA stored in chromosomes
• How many pairs of chromosomes do humans have?

  23 pairs
• What are diploid cells?

  Cells with 23 pairs of chromosomes
• What are haploid cells?

  Gametes with 23 single chromosomes
• How do new cells form for growth and repair?

  By duplicating through mitosis
• What happens during mitosis?

  Genetic material is duplicated and divided
• What are stem cells?

  Cells that haven't specialized yet
• Where are stem cells found in humans?

  In embryos and bone marrow
• What can stem cells be used for?

  To combat conditions like diabetes and paralysis
• What is cloning used for in plants?

  To prevent extinction and produce specific crops
• What is diffusion?

  Movement from high to low concentration
• What is osmosis?

  Diffusion of water across a membrane
• What happens when there is a higher concentration of glucose outside a cell?

  Water moves out, decreasing cell mass
• How can the rate of diffusion and osmosis be increased?

  By increasing concentration difference, temperature, or surface area
• What is the practical for osmosis using potatoes?

  Weigh cylinders in varying sugar solutions
• How do we calculate percentage change in mass?

  Final mass minus initial mass divided by initial mass times 100
• What does a negative change in mass indicate?

  The potato lost mass due to osmosis