AQA GCSE- biology p1

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

  Cells, organization, infection, and bioenergetics
• What types of cells can be observed with a light microscope?

  Normal cells and possibly the nucleus
• What advantage does an electron microscope have over a light microscope?

  It reveals finer details of organelles
• How can you calculate the actual size of a cell?

  Divide image size by magnification
• What are the two main groups of cells?

  Eukaryotic and prokaryotic cells
• What characterizes eukaryotic cells?

  They have a nucleus containing DNA
• Where is DNA found in prokaryotic cells?

  In a ring called a plasmid
• What is the function of the cell membrane?

  It keeps everything inside the cell
• What is the role of the cytoplasm?

  It is where most chemical reactions occur
• Where does respiration take place in a cell?

  In the mitochondria
• What is the function of ribosomes?

  They assemble proteins
• What do chloroplasts contain and what is their function?

  They 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 is the purpose of incubating the culture at 25°?

  To allow bacteria to grow
• What formula is used to calculate the area of circles?

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

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

  23 pairs
• What are gametes and how many chromosomes do they have?

  They have 23 chromosomes, not pairs
• What process do new cells undergo for growth and repair?

  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
• How can stem cells be used in medicine?

  To combat conditions like diabetes and paralysis
• What is diffusion?

  Movement from high to low concentration
• What is osmosis?

  Diffusion of water across a membrane
• How can the rate of diffusion be increased?

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

  Weigh, place in sugar solutions, and measure mass change
• What does a negative change in mass indicate in osmosis?

  The cell has lost water
• What is active transport?

  Movement against a concentration gradient using energy
• What is a tissue?

  A group of similar cells working together
• What do organs do?

  They perform specific functions in an organ system
• What is the role of bile in digestion?

  Neutralizes stomach acid and emulsifies fats
• What are enzymes?

  Biological catalysts that speed up reactions
• What is the lock and key principle in enzymes?

  Substrate fits into the enzyme's active site
• What happens to enzymes at high temperatures?

  They can denature and lose function
• How do you determine the optimum temperature or pH for an enzyme?

  By plotting times against temperature or pH
• What does iodine test for?

  Presence of starch