The Whole of Paper 1

• What is the basic unit of all forms of life?

  Cells
• How do structural differences between types of cells affect their functions?

  They enable cells to perform specific functions
• What controls the differences in cells?

  Genes in the nucleus
• What process do cells undergo to divide and grow?

  Mitosis
• What happens when cells are isolated at an early growth stage?

  They can grow into different cell types
• What technology has developed from the ability of early-stage cells to differentiate?

  Stem cell technology
• How does stem cell technology benefit medicine?

  It allows repair of damaged organs
• What do plant and animal cells have in common?

  Cell membrane, cytoplasm, nucleus
• What is a key difference between eukaryotic and prokaryotic cells?

  Eukaryotic cells have a nucleus
• What is the genetic material structure in bacterial cells?

  A single DNA loop and plasmids
• What are the main parts of most animal cells?

  Nucleus, cytoplasm, cell membrane
• What additional parts do plant cells have compared to animal cells?

  Chloroplasts and a permanent vacuole
• What strengthens plant and algal cells?

  Cell wall made of cellulose
• Why is it important to estimate sizes of sub-cellular structures?

  To judge their relative size or area
• What is the required practical activity for observing cells?

  Use a light microscope to observe cells
• What is cell specialization?

  Cells adapting to perform specific functions
• Name three specialized animal cells.

  Sperm, nerve, muscle cells
• Name three specialized plant cells.

  Root hair, xylem, phloem cells
• What is the importance of cell differentiation?

  It allows formation of different cell types
• How do most animal cells differentiate?

  At an early stage of development
• How do many plant cells differentiate?

  They retain the ability throughout life
• What is the main purpose of cell division in mature animals?

  Repair and replacement of cells
• How do bacteria multiply?

  By binary fission
• What conditions allow bacteria to multiply quickly?

  Enough nutrients and suitable temperature
• What are two methods to grow bacteria?

  Nutrient broth solution and agar gel plate
• Why are uncontaminated cultures important?

  For investigating disinfectants and antibiotics
• What is aseptic technique?

  A method to prepare uncontaminated cultures
• Why must Petri dishes and culture media be sterilized?

  To prevent contamination
• Why should inoculating loops be sterilized?

  To prevent contamination of cultures
• Why should Petri dish lids be secured and stored upside down?

  To prevent contamination from airborne particles
• At what temperature should cultures generally be incubated in schools?

  25°C
• What is the formula for calculating magnification?

  Magnification = size of image / size of real object
• What is the role of electron microscopy?

  To study cells in finer detail
• What do chromosomes contain?

  DNA molecules
• How are chromosomes arranged in body cells?

  Normally found in pairs
• What is the cell cycle?

  A series of stages for cell division
• What happens to genetic material during the cell cycle?

  It is doubled and then divided
• What must a cell do before it divides?

  Grow and increase sub-cellular structures
• What occurs during mitosis?

  Chromosomes are pulled to each end of the cell
• What is the final step of cell division?

  Cytoplasm and cell membranes divide