cell biology

• 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 allows us to see finer details
• 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 distinguishes eukaryotic cells from prokaryotic cells?

  Eukaryotic cells have a nucleus
• What is the function of the cell membrane?

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

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

  Mitochondria
• What do ribosomes do?

  Assemble or synthesize proteins
• What is the function of chloroplasts in plant cells?

  Photosynthesis occurs in chloroplasts
• What is a permanent vacuole in plant cells used for?

  Storing 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 during culturing?

  To move microbes away and destroy them
• What is the purpose of incubating the culture at 25°?

  To allow bacteria to grow
• How do we calculate the area of a circle in this context?

  $A =$$\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 in terms of chromosome number?

  They have 23 chromosomes
• What process do new cells undergo for growth and repair?

  Mitosis
• What happens during the mitosis process?

  Genetic material is duplicated
• 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
• What is diffusion?

  Movement from high to low concentration
• What is osmosis specifically?

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

  By increasing concentration difference
• What is the practical method for osmosis using potatoes?

  Weigh, place in sugar solutions, and reweigh
• What is active transport?

  Movement against a concentration gradient
• What do similar cells form when organized together?

  A tissue
• What do tissues form?

  Organs
• What is the role of enzymes?

  They act as biological catalysts
• What does amylase do?

  Breaks down starch into glucose
• 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
• What is the optimum temperature for enzyme activity?

  The temperature at which activity is highest
• What does iodine test for?

  Presence of starch
• What does Benedict's solution test for?

  Presence of sugars
• What does biuret reagent test for?

  Presence of proteins