Topic 1 - B1

• What are eukaryotic cells + example?


  A type of complex cell (animal and plant cell)
• What is a prokaryotic cell + example?


  A type of small simple cell (bacteria)
• What is a small ring of DNA called?

  Plasmids
• What makes up cell sap?


  Weak solution of sugar and salts
• Where does photosynthesis occur?


  Chloroplasts
• What does chlorophyll do?

  Absorbs the light needed for photosynthesis
• What is the equation of magnification?


  magnification = image size / real size
• What is differentiation?


  A process by which a cell changes to become specialized for its job
• How does a cell become specialised?

  Cells develop different subcellular structures which allows them to carry out specific functions
• What is a sperm cell specialised for?

  Reproduction
• What is a nerve cell specialised for?

  Rapid signalling
• What are muscle cells specialised for?


  Contracting quickly
• What are root hair cells specifised for?

  Absorbing water and minerals
• What are the phloem and xylem cells specialised for?

  Transporting substances:

  • phloem

  -> food

  • xylem

  -> water
• How are sperm cells specialised for reproduction?


  • long tail + streamlined head

  -> help swim to egg

  • lots of mitochondria

  -> provide energy needed

  • carries enzymes

  -> to digest through egg cell membrane
• How are nerve cells specialised for rapid signaling?

  • long

  -> cover more distance

  • branched connections

  -> to form a network throughout body
• How are muscle cells specialised for contracting quickly?

  • long

  -> so they have space to contract

  • lots of mitochondria

  -> to generate energy needed for contraction
• How are root hair cells specialised for absorbing water and minerals?

  • big surface area (from "hairs")

  -> help absorb water and minerals from soil
• How are the phloem an xylem cells specialised for transporting substances?

  • Phloem

  -> very few subcellular structures (food - sugar - can flow through)

  • Xylem

  -> hollow in centre (water and minerals - can flow through)
• What happens during the growth and DND replication stage of the cell cycle?

  (1) DNA spreads out in long strings

  (2) cell grows and increases amount of subcellular structures (mitochondria and ribosomes)

  (3) cell duplicates DNA
• What happens during the mitosis stage if the cell cycle?

  (1) chromosomes line up in centre of cell and cell fibres pull them apart

  (2) membranes form around each sets of chromosomes -> becomes nuclei of two cells as nucleus has divided

  (3) cytoplasm and cell membrane divide
• How do prokaryotic cells replicate?

  Binary fission
• What is the proccess of binary fission?

  (1) circular DNA and plasmids replicate

  (2) cell becomes bigger and circular DNA strands move to opposite poles

  (3) cytoplasm begins to divide and new cell walls form

  (4) cytoplasm divides
• Where are stem cell found in the body?


  • embryo (early stage of baby growning)

  • bone marrow
• Where in a plant are stem cells found?

  Meristems
• What is the definition of diffusion?

  The spreading out of particles from an area of high concentration to an area of lower concentration
• What is the definition of osmosis?


  The movement of water molecules across a semi permanable membrane from a region of high water concentration to a region of lower water concentration
• PRACTICAL: how does sugar solutions affect plant tissue?

  INV- concentration of sugar solution

  DV- chip mass

  CV- volume of solution, temperature, time, type of sugar

  (1) cut up potatoes and fill beakers with different sugar solutions (pure water, 1 mol/dm³, 0.6 mol/dm³, 0.2 mol/dm³)

  (2) measure mass of potato then place into different beakers

  (3) leave for 24hrs

  (4) take potato out, dry then measure mass again

  (5) calculate percentage change in mass
• What is the definition of active transport?


  The movement of particles against the concentration gradient (from an area of lower concentration to an area of higher concentration) using energy transferred during respiration
• Where is active transport used in a plant and in the body?

  • Plant

  -> minerals going from soil into root hair cells

  • Body

  -> glucose and amino acids going from gut to blood
• How does oxygen water vapour and carbon dioxide move in and out of a leaf?

  Diffusion
• What does the stomata do?


  Allows CO2 into the leaf and oxygen water vapor out of the leaf