Biology

• What is meant by an enzyme being denatures

  when its active shaoe changes shape
• explain why the structure of the egg cell membrane changes after fertilisation

  to prevent further sperm from entering the egg ehich makes sure the offspring has the correct amount of DNA
• What is active transport?

  the movement of particles across a membrane against a concentration gradient
• what is an embryonic stem cell?

  an undifferentiated cell found in early human embryos that has the potential to differentiate into any kind of cell
• describe how electrical impulses are transferred from neurone to neurone

  electrical impulses are transferred from neurone to neurone by neurotransmitters which diffuse across the synapse
• Give a risk of selective breeding

  The population may have an increased susceptibility to disease
• how is antibiotic resistance evidence for the theory of natural selection

  it makes the bacteria betteradapted to the environment in which anyibiotics are present. Antibiotic resistance becomes more common over time.
• What is genetic engineering?

  The modification of the genome of sn organism to introduce desirable characteristics