inheritance, variation and evolution

• DNA is a ........... made up of ................strands forming a ..................helix

  DNA is a polymer made up two strands forming a double helix
• in what subcellular structure is DNA found in plant and animal cells

  nucleus
• how many chromosomes do humans have?

  23 each pair
• Give the definition of a gene

  a short section of DNA that codes for a particular code of amino acids that are put together to make specific protein
• how many different amino acids are there?

  20
• what is the genome of an organism

  the entire genetic material of an organism
• what is the human genome project

  the human genome project was a project where scientist found all the genetic material in humans
• Explain how knowing the genome of individuals can help with the medication and treatment given to individuals with certain genes

   By knowing the genomes of individuals, we can make more informed decisions as to the most effective way to treat a particular individual with certain genes. This can be with respect to the type of drugs, the dosage, the type of treatment etc.
• another benefit of the human genome project

  tracing the migration patterns of humans over time
• Give two drawbacks of scanning the DNA of individuals to see if they have an increased risk of developing certain diseases.

  increased stress or anxiety

  may lead to gene-ism where individuals that have certain genetic disorders or certain genes may feel like they shouldn’t have children so that they do not pass on their faulty genes.
• how many individuals involved in sexual reproduction

  2
• what are gametes

  sex cells
• how many chromosomes do gametes have?

  23
• in animals what is the name of male gametes

  sperm
• what is the name of female gametes

  eggs
• what is the name of the cell division that produces gametes

  meiosis
• This question is referring to humans. A male gamete fertilises a female gamete. How many chromosomes will the cell produced have?

  46
• Is the genetic material for the offspring from sexual reproduction identical or different to the parent(s)? And does this mean that we have variation in the offspring?

  The offspring will be genetically different to the parents, which means that we will have variation in the offspring
• Give an advantage of sexual reproduction. Explain your advantage.

  Sexual reproduction brings variation into the population. Variation allows species to adapt to new or changing environments, which may give them a survival advantage. Also, variation in the offspring may mean that diseases are less likely to affect an entire population because the population is genetically different
• Give 2 disadvantages of sexual reproduction


  1. it takes time and energy to find mates
  2. sexual reproduction is a longer process than asexual
• how many individual are there in asexual reproduction

  1 individual
• Is the genetic material for the offspring from asexual reproduction identical or different to the parent(s)? And does this mean that we have variation in the offspring?

  The offspring are genetically identical to the parent, which means that there is no variation in the population
• name of the cell division in asexual reproduction

  mitosis
• two advantages of asexual reproduction

  • It is a very quick process so organisms can rapidly increase their population
  • Only 1 parent is needed so you do not need to waste time and energy to find a mate. You can also reproduce if you are in isolation
• Give a disadvantage of asexual reproduction explain your reason

  • There is no genetic variation in the offspring/ population as all of the offspring are genetically identical. This means that the species may be only suited to one habitat/ less able to cope with different environments. Also, the population may be more susceptible to a disease, which could wipe out/ affect the entire population
• what are gametes give names of the male and female gametes

  Gametes are sex cells, the male gamete is sperm and female is egg
• 1. Gametes are produced by a process known as meiosis.What happens to the genetic material at the start of the meiosis process?

  the genetic material is copied/duplicated
• b) how many cell divisions take place in meiosis

  2 cell division
• describe what happens during fertilisation

  fertilisation is where the sperm cells and eggs cells fuse together
• Scientists working on the ‘Human Genome Project’ have now mapped the entire genetic code of humans. Explain one way this could be important for people in the future

  identifying genes that causes inherited genes