jan 2023

• Describe how a molecule of messenger RNA (mRNA) is made in the nucleus of a cell (3)

  RNA polymerase binds to DNA

  
  

  RNA nucleotides base paired with DNA template strand
• organelle where translation happens

  ribosome
• anticodon function


  specific for a particular amino acid and binds to mRNA
• Explain what happens to the body during an asthma attack (3)

  airways become narrow

  
  

  smooth muscle contracts

  
  

  less oxygen available to cells

  
  

  increased mucus production
• treatment for asthma attack

  inhaler
• 2 symptoms of Dermatitis

  rash

  
  

  itchiness
• Explain the effects of hyperplasia

  cell numbers increase

  
  

  uncontrolled cell division

  
  

  growth of tumours
• advantage of using chemotherapy for autoimmue disorders

  damages dividing cells

  
  

  FEWER WBC to attack body
• disadvantage of using chemotherapy for autoimmue disorders

  weakened immune system (immunocompromised)

  
  

  more likely to be infected by pathogens
• antigen binding site function

  -complimentary in shape to antigen

  
  

  -so antibody is specific for antigen/pathogen
• hereditary mutation


  can be passed on to offspring + affects germ line

  
  

  change in gamete
• acquired mutation


  not passed on to offspring

  
  

  change in single somatic cell later in life
• amniocentesis


  needle inserted through abdomen into uterus

  
  

  guided by ultrasound

  
  

  sample taken from amniotic fluid and karyotype produced
• vitamin D


  needed for healthy bone development
• vitamin K


  helps blood clot during injury
• mineral used to carry oxygen in haemoglobin

  iron
• cholesterol_______cell membrane fluidity


  regulates/controls
• glycoprotein func's


  cell signalling/stabilises membrane structure by forming hydrogen bonds with water
• oxygen


  non polar small molecule

  simple diffusion

  transported directly across membrane
• amino acids


  large not lipid soluble

  
  

  use of carrier proteins
• Exocytosis is a bulk transport process that releases substances from the cell. Explain how (3)

  substances packaged into vesicles

  
  

  vesicles transported to membrane

  
  

  vesicles fuse with membrane

  
  

  process requires ATP
• Explain how lack of oxygen can cause the cell to swell (4)

  lack of oxygen means cells cannot respire aerobically

  
  

  Less ATP produced

  
  

  sodium ions not pumped out of cell

  
  

  water potential of cell decreases (osmotic potential increases)

  
  

  water moves into cell by osmosis
• c ring cartillage

  to hold open the airway/allows air into lungs
• Explain how blood loss is stopped when the skin is cut