Biology

• Enzyme


  A substance. that breaks down large molecules into smaller molecules.

  
  

  They are biological catalysts.

  
• Lipase


  An enzyme that breaks down fat molecules into smaller molecules called fatty acids.
• Amylase


  An enzyme in saliva that breaks down starch into sugar.

  
  

  Starch is a type of carbohydrate.

  
• Carbohydrase


  An enzyme that breaks down starch into sugar. There different examples of this enzyme, such as the one that is found in saliva.
• Small intestine


  The part of the digestive system where most digestion takes place.

  
• Stomach


  This part of the digestive system only digests protein.
• Tissue


  Group of cells that work together to perform a similar function
• Organ


  A collection of tissues that carry out a specialized function of the body

  
• Cell


  The basic unit of structure and function in living things
• Organ system


  A group of organs that work together in performing vital body functions.

  
• The two types of digestion

  Mechanical and chemical
• Mechanical digestion


  The type of digestion that uses teeth.

  
  

  It increases the surface area of food so that it can be broken quicker by enzymes.

  
• Chemical digestion


  The type of digestion that uses enzymes.

  
  

  Enzymes break down large molecules such as carbohydrates into smaller molecules.
• Substrate


  The substance that is broken down by an enzyme..

  
• Protease


  An enzyme that breaks down protein molecules into smaller amino acid molecules.

  
• Molar teeth


  The type of teeth that grind food.

  
• Incisor teeth


  The type of teeth that cut food

  
• Canine teeth


  The type of teeth that tear food.

  
• Ligaments


  Connect bone to bone

  
• Tendons


  Connect muscle to bone

  
• Cartilage


  A connective tissue that is more flexible than bone and that protects the ends of bones and keeps them from rubbing together.

  
• Iodine test


  Test for starch.

  
  

  The colour of iodine solution goes from pale yellow to black if starch is present.

  
  

  There is less or no black colour if the starch has been mixed with the enzyme amylase, because the starch has been broken down. In other words, the iodine remains a yellow colour.

  
  

  There is a black colour if the starch is mixed with the enzyme protease. This is because protease doe not break down starch, only protein. The starch causes the iodine to go blue-black.

  
• Large intestine


  The part of the digestive system where water is absorbed.

  
  

  Diarrhoea is caused by water not being absorbed in this part of the body, leading to dehydration.

  
• Fertilisation


  Joining of the nucleus of a male gamete with the nucleus of a female gamete.

  
• Gamete


  Sex cell
• Male gamete


  Sperm cell

  
• Female gamete


  Egg cell

  
  

  Also known as an "oocyte".

  
  

  It has a thick outer wall that must be broken down by enzymes of the sperm cell, if fertilisation is to take place.

  
• Chromosome


  A large molecule of DNA.

  
  

  There are 23 chromosomes from the egg cell of mum and 23 from the sperm cell from dad, in humans. This gives 46 chromosomes in total for each cell of the body.

  
  

  Chromosomes are known as "hereditary material" as they are responsible for the features that we inherit from mum and dad.

  
  

  It is essential that cells have exactly 46 chromosomes. Cells that have too many or too few chromosomes cannot survive.

  
• The only cell in the human body that does not contain DNA

  Red blood cell.

  
  

  It does not have a nucleus.
• Testis


  Male reproductive organ that produces sperm cells and hormones.

  
  

  It is kept at a temperature of 35 degrees C.

  
  

  If this organ is too hot, sperm cells can be damaged.

  
• Uterus


  Female reproductive organ where the fetus develops to become a baby.

  
• Sexual reproduction


  A reproductive process that involves two parents that combine their genetic material to produce a new organism, that differs from both parents.
• Asexual reproduction


  A reproductive process that involves one parent producing genetically identical offspring.

  
  

  This is also known as "cloning".
• Advantage for a species of sexual reproduction

  The genetically different offspring that are produced may be able to survive in a changing environment.
• Advantages for a species of asexual reproduction

  The offspring are produced without the need to find a mate.
• Disadvantage for a species of sexual reproduction

  A mate needs to be found.
• Disadvantage for a species of asexual reproduction

  The offspring are identical and may not be able to survive in a changing environment.
• Implantation


  The process by which the zygote attaches to the wall of the uterus.

  
• Ectopic pregnancy


  A pregnancy outside of the womb, usually in one of the fallopian tubes.

  
• Oviduct


  The tube that connects the ovary to the uterus.

  
  

  Also known as the "fallopian tube".