knowledge questions (b1) !!

• What are common features of plant and animal cells (eukaryotes)?

  Nucleus, cell membrane, mitochondria, cytoplasm
•  Which are bigger; bacterial cells (prokaryotes) or eukaryotes? 

  Eukaryotes
• True or false? “Prokaryotic cells have a cell wall.”

  True (but not all do)
• True or false? “Prokaryotic cells have a nucleus.”

  False
• In what form is the genetic material in a prokaryotic cell?

  A single DNA loop in the cytoplasm
•  Name five common parts of animal and plant cells.

  Cell membrane, cytoplasm, mitochondria, ribosomes and nucleus
• Name two further features of a plant cell.

  permanent vacuole and cell wall
• Describe the function of the nucleus.

  Controls the activities of the cell (e.g growth and metabolism) and carries the genes
• Describe the cytoplasm and its function

  A jelly like substance where organelles are suspended and where most chemical reactions take place
•  Describe the function of the cell membrane.

  To control the substances that enter and leave the cell (e.g glucose, oxygen and mineral ions)
• Describe the mitochondria and its function

  Structures in the cytoplasm where aerobic respiration takes place, releasing energy for the cell. They are very small (around 1μm long and 0.5μm wide).
• Describe the function of the ribosomes.

  The site of protein synthesis, making all the proteins needed in the cell.
• Describe the function of the chloroplasts.

  These contain the green substance chlorophyll, which absorbs light for photosynthesis. They are around 3-5μm long.
•  Describe the function of the permanent vacuole.

  A space filled with cell sap in the middle of a cell, it keeps the cell rigid to support the plant.
• Which strong material is the cell wall of plant and algal cells made from? 

  Cellulose - It strengthens the cell and provides support
• What is the definition of a cell? 

  the smallest unit that can live on its own and makes up all living organisms and tissues of the body
• What is the definition of a tissue?

  A group or layer of cells that work together to perform a specific function
• What is the definition of an organ? 

  A structure made up of groups of different tissues, working together to perform specific functions
•  What is the definition of an organ system?

  A group of organs with related functions, working together to perform certain functions
• Describe a specialisation of a sperm cell.

  Fertilization of the female egg cell - long, slender tails called flagella that allow them to swim towards the egg cell.
• Describe a specialisation of a nerve cell.

  They are thin, and can be more than one metre long in your spinal cord. This means they can carry messages up and down the body over large distances very quickly
• Describe a specialisation of a muscle cell.

  Muscle cells contract and relax, allowing different types of movement and contain filaments of protein that slide over each other to cause muscle contraction.
• Describe a specialisation of a root hair cell.

  Root hair cells. are adapted for taking up water and mineral ions by having a large surface area to increase the rate of absorption.
• Describe a specialisation of a xylem cell.

  The xylem is specialised to transport water up the stem of a plant and into the leaves and they contain a substance called lignin that strengthens the cell walls of xylem cells.
• Describe a specialisation of a phloem cell.

  The phloem is specialised to transport food products to parts of the plant where they are needed. The end walls of phloem cells contain small holes to allow food products to move up and down the phloem vessels.
•  What is “cell differentiation”?

  The process of cells becoming specialized in their structures and function and performing a certain job in the body
• When do most animal cells differentiate?

  In the early stages of life, as the organism develops
• What is different about plant cells’ differentiation?

   The ability to differentiate is never lost.
• In mature animals, what is cell differentiation used for?

  The development of creating new cell types
• What are the two advantages of electron microscopes over light microscopes? 

  They have a higher range of magnification and higher resolution
• What is the “resolution” or “resolving power” of a microscope?

  How much detail you can see on an image
• What are the three forms of equation used to calculate magnification (M), the image size (I) or the actual  size of an object (A)? 


  • Magnification = Image ÷ real
  • Image = Magnification X real
  • Real = Image ÷ Magnification
• What is 1340000 nm expressed in standard form? 

  1.34 × $10^6$
• What is 0.0000001 µm expressed in standard form?

  1 ×$10^-7$
• By what process do bacterial cells divide?

  Binary fission
• If provided with enough nutrients and a suitable temperature, how often can bacterial cells divide?

  Every 20 minutes
• What is a “contaminant”?

  a substance that pollutes, spoils, or poisons something
• What should you do with Petri dishes and culture media before use?

  Sterylise them
• How do you sterilise inoculating loops?

  Pass it at an angle through the flame of a gas burner until the entire length of the wire becomes orange from the heat
• How should a Petri dish be stored in school? 

  Invert the plate and store it upside down