topic 1 biology edexcel

• Eukaryotic cells have a nucleus whereas prokaryotic cells do not. eukaryotic cells are animal and plant cells where as prokaryotic cells are simpler and smaller e.g bacteria.
• The nucleus contains genetic material and controls activities of the cell.
• The cytoplasm is where the chemical reactions take place.
• cell membrane controls what goes in and out of the cell.
• Mitrochondria releases energy
• Ribsome where protein synthesis is made
• Only animal cells have a vacule and this contains cell sap.
• Chloroplast is where photosynthesis occours.
• In a bacteria cell there are two types of DNA the first being chromosomal DNA this controlls the cells activities.Plasmid DNA contains genes for things like drug resistance.
• Bacteria cells have a cell membrane(allows for things to leave and enter the cell) they also have ribosome(for protein synthesis)and a flagellum that rotates to move away from harmful substances like toxins.
• Egg cells are specialised as they have a cell membrane that changes structure in order for no sperm cells to enter after fertilistation.Egg cells also have a cytoplasm that carries nutrients to feed the embryo.Egg cells also have a haploid nucleus in order for there to be a dipliod amount of chromosones after fertilisation.
• sperm cells are specialised as they have a long tail meaning they can swim to the egg cell.Sperm cells are also specialised as they have a diploid number of chromosomes so after fertilisation the zygote has a diploid number of chromosomes. It also has an acrosomes at the head this is an enzyme meaning it can digest the cell membrane of the egg cell.It also has a lot of mitrochondia in order for the sperm cell to have energy and swim to find the egg cell.
• what direction do cilliated cells move substances?

  in one direction along the surface of the tissue.
• whats resolution?


  being able to distinguish two points and for it to be seen in more detail.
• whats special about electron microscopes?


  they have a higher magnification and a higher resolution
• whats a disadvantage of the electron microscope


  the organisms have to be dead
• whats an advantage of the light microscope

  living organisms can be seen
• whats a disadavntage of using light microscopes?


  not as high of a resolution and magnification as the electron microscope
• How would you prepare an onion to be placed on alight microscope?

  1. Peel a thin layer. 2.stain the cell. 3. Place a cover slip without any airbubbles 3.clip the slide onto the stage
• How would you adjust the magnification of the microscope 


  place x40 objective lens,makesure the slide is furthest down and slowly bring it higher, make sure the eyepiece is on the smallest one
• how would you draw a scientific drawing of a specimen 


  use a sharp pencil draw the outlines, dont include shadings,lable the features on the diagram with a straight line
• what the conversions 


  milli,micro,nano,pico times by a thousand to get each one
• explain the lock and key thoery


  The subsrate is complementry to the active site this means they form enzyme substrate complex if it doesnt fit it wont be catalysed
• what happens to the rate of the enzyme if the temperature changes 


  as the temp increases so does the rate of reaction but after it reaches the optimum the enzyme then denatures damaging the active site meaning enzyme active site changes shape
• pH effects enzymes 


  As the ph increases so does the rate of reaction after it reaches the optimum pH the enzyme active site also changes shape meaning no more enzyme subsrate complex forms
• subsrate conc


  higher the conc the higher the rate of reaction is faster but after the optimum the enzyme begins to denature
• starch


  amylase sugar
• protease

  protein amino acids
• lipease

  lipids and fatty acids
• diffusion


  the movement of particles from an area og high conc to an area of low conc
• osomosis


  the movement of water molecules from an area of high conc to an earea of low conc across a partially permable membrane
• active transport 


  the movement of particles from an area from an area high conc to an area of low conc across the concentration gradient