biology

• is a plant cell a prokaryotic or a eukaryotic cell?

  eukaryotic
• what is the difference between a eukaryotic cell and a prokaryotic cell? 


  a eukaryotic cell is a complex cell e.g plant or animal cells but a prokaryotic cell is a small simple cell e.g bacterium cell
• In which sub- cellular structures do most of the reactions of aerobic respiration take place 


  mitochondria
• Describe the main similarities between bacterial cells and plant cells 


  they both have a cell membrane, cell wall and cytoplasm
• what are the main differences between plant cells and bacterial cells 


  plant cells have chloroplast and a mitochondria but bacterial cells do not. Plant cells also have a true nucleus but bacterial cells have a singular strand of DNA that floats freely in cytoplasm. Bacterial cells may also contain small rings of DNA called plasmids.
• what does the cell membrane do? 


  This holds the cell together and controls what enters and leaves.
• what does the nucleus do 


  This contains the genetic material that controls the activities of the cell.
• what does the cytoplasm do

  This is a gel-like substance where chemical reactions take place. It contains enzymes that control these reactions
• what is the purpose of the fine adjustment knob on a light microscope? 


  It is used to focus the lens until a clear image is formed of what is on the slide A
• what is resolution 


  the ability to distinguish between two points
• what is magnification 


  the process of making something look bigger
• How has electron microscopy increased biologists understanding of cells 


  Electron microscopes let us study cells in much finer detail than light microscopes. This has enabled biologists to see and understand more sub-cellular structures, such as ribosomes and plasmids, and the internal structures of mitochondria and chloroplasts.
• why do we stain cells on slides? 


  Iodine is a stain. It is used to highlight objects in the cell by adding colour to them so they are easier to see
• magnification = image size/real size
• Which cells in plants are specialised for absorbing water and minerals from the soil? 


  Root hair cells - found on the surface of of plant roots
• what is the function of a sperm cell 


  to transport male DNA to female DNA in eggs for reproduction
• how does the ability to differentiate differ between plant cells and animal cells? 


  The ability to differentiate is lost at an early stage in most animal cells but many plant cells don't lose this ability
• what is the function of a zylem cell 


  to transport water and minerals up plants
• how are zylem specialised for their function? 


  the cells are long and are joined end to end, forming hollow tubes. This means substances can flow through them.
• what is the function of a nerve cell 


  It carries electrical impulses - signals - From one part of the body to another
• How is a nerve cell adapted for its function? 


  The cell is long and has branched connections at its ends to connect to other nerve cells and form a network throughout the body. This allows for rapid signaling
• Exocrine acinar cells function to produce lots of digestive enzymes which are then secreted from the pancreas . Suggest one way that these cells may be specialised for their function 


  E.g the cells may contain a large number of ribosomes for th synthesis of the digestive enzymes