bio paper 1

• antibodies are proteins that protect you when an unwanted substance enters your body. how it works: circulates in the blood, recognises foreign substances like bacteria and viruses and neutralizes them.
• antigens 


  antigens: molecules often proteins are located on the surface of the cell tat trigger a specific immune response
• antigen vs antibody 


  antigens allow your body to create a defence against future invaders, antibodies circulate in your body once created to identify, attack and destroy the same type of antigens if they enter the body again
• meiosis 


  is a type of cell division that produces four daughter cells, each with half of the chromosones.
• cell wall gives..


  structure & support
• chloroplasts 


  is where photosynthesis takes place, full of chlorophyll
• vacuole 


  is where water and cell sap is stored
• ribosomes


  is where protein is made
• nucleus 


  stores dna
• cell membrane 


  controls what goes in and out of the cell
• cytoplasm


  where chemical reactions take place
• mitochondria 


  releases energy
• white blood cells


  part of the bodies immune system, help fight infection and other diseases
• lymphocytes 


  help fight viruses and make antibodies
• red blood cells


  carry oxygen from lungs and deliver it throughout the body
• pathogens 


  a micro organism with the potential to cause harm in the form of an infectious disease
• diffusion 


  natural movement of particles from an area of higher concentration to an area of lower concentration
• examples of diffusion

  • carbon dioxide diffuses into a leaf through the stomata
• osmosis in potatoes 


  results: percentage change in mass of each potato, slice is calculated and recorded, indicating whether mass was gained or lost
• osmosis in potatoes 


  conclusion: results show that when the solution is very dilute, water enters the potato cells due to osmosis
• stem cells

  are cells that divide to produce many types of cell
• embryonic stem cells 


  are taken from embryos at a very early stage of division
• adult stem cells


  are found in differentiation tissue, such as bone or skin- they divide to replace damaged cells
• meristems 


  plants have meristems that are found in rapidly growing parts of the plant
• chromosone 


  a structure found inside the nucleus of a cell, made up of proteins and dna
• pathogen 


  a micro organism with the potential to cause harm in the form of an infectious disease
• gametes


  sex cells
• haploid 


  half of the chromosomes
• diploid 


  full set of chromosomes
• homozygous 


  both alleles are the same
• heterozygous 


  both alleles are different
• antibodies 


  proteins that protect you when and unwanted substance enters your body
• antigens


  molecules often proteins located on the surface of cells that trigger a specific immune response
• antigen vs antibody


  antigens allow your body to create a defence against future invaders, antibodies circulate in your body to identify attack and destroy the same type of antigens if they enter the body again
• specialised cells in animals

  • red blood cells
  • egg and sperm cells
  • nerve cells
  • bone cells
  • smooth muscle cells
• specialised cells in plants

  • xylem, phloem
  • root hair cells
  • stoma cells
• mitosis stage 1


  interphase: at the end of interphase chromosomes become more visible, dna has already been copied
• mitosis stage 2


  prophase: each chromosome consists of two chromatids
• mitosis stage 3 


  metaphase: nuclear membrane breaks down, chromosomes line up along the middle of the cell
• mitosis stage 4 


  anaphase: chromatids separate and one chromatid from each pair is pulled to each pole of the cell