Genetics

Question 1

Outline the steps of Gene Transfer

Answer 1

1. identify gene of interest within the DNA
2. identify vector, the plasmid of prokaryotic DNA
3. Use restriction enzymes to extract gene from DNA and cut space for DNA to go into the plasmid. The enzyme will create sticky ends within the DNA and vector, ensuring easy insertion.
4. Employ ligase enzyme to join vector and gene together and fuse complimentary sticky ends together.
5. Introduce recombinant construct into host cell. Now it can produce designated substance.

• many times used to produce proteins, such as insulin

Question 2

Outline the steps for Gel Electrophoresis

Answer 2

• used to separate DNA based on mass/size/ charge
  1. restriction enzymes used to chop DNA into fragments
  2. fragments placed in wells on one side of gel substance
  3. electrical current passed through gel
  4. fragments light in mass and charged will move faster towards the positive charge

Question 3

Where does genetic variation come from?

Answer 3

• random/ independent assortment during Metaphase I and II of Meiosis
• random fertilization
• crossing over during prophase I of meiosis

Question 4

What is the human genome project used for?

Answer 4

• compare genetic makeup of populations
• track ancestry
• track migrations of populations

Question 5

Describe base substitution of sickle cell anaemia

Answer 5

• substitution of valine for glutamic acid in hemoglobin bases
• causes sickle shape of red blood cell instead of biconcave
• affects ability of red blood cells to carry oxygen
• substitution also causes haemoglobin to crystallize inside of red blood cell, leading red blood cells to become less flexible so they get stuck in capillaries
• resistant to Malaria, a beneficial adaptation in Africa

Question 6

Outline steps of Karyogram

Answer 6

1. stain cell and place under light microscope
2. take picture of condensed chromosomes during Metaphase
3. cut out chromosomes from pictures
4. sort them according to size, banding pattern, shape into homologous chromosomes

Question 7

Outline steps of Autoradiography

Answer 7

• used as a way to get images of DNA so their lengths can be measured
  1. DNA is inserted with radioactive form of thymidine
  2. DNA left in dark for a period of time
  3. DNA placed under electron microscope
  4. black dots appearing on DNA represent the radioactively decaying atoms

Question 8

Different ways to acquire cells for karyotyping

Answer 8

1. Extract cells from amniotic fluid
   - using hypodermic needle
2. Extract cells from villus tissue of placenta

Question 9

Outline Plant cloning

Answer 9

• vegetative propagation- small pieces can grow independently
• due to meristematic tissue- totipotent stem cells
• occurs in garlic and onion bulbs, and strawberry runners
• produce genetically identical plants

Question 10

Outline the different methods of Animal Cloning

Answer 10

BLACK BEARS FART POOP

1. Binary Fission- parent organism divides into 2 genetically identical daughter organisms. Eg bacteria
2. Budding- cells split off from parent organism, forming daughter organism. Ex yeast
3. Fragmentation- new organisms grow from fragments of parent organism. Starfish
4. Parthenogenesis- organisms grow from unfertilized ovum. ex frogs

Question 11

Outline the 2 different methods of Human Cloning

Answer 11

• monozygotic- 2 identical twins are produced from a fertilized zygote splitting into 2 cells
• dizygotic- 2 non-identical twins are produced from unfertilized egg splitting into 2 cells, and fertilized from 2 different sperm cells

Question 12

Outline steps of PCR (Polymerase Chain Reaction)

Answer 12

1. add nucleotides and DNA
2. Heat to 90 degrees Celsius. The heat acts as Helicase, breaking Hydrogen bonds in DNA and exposing bases
3. Low temperature to 55 degrees Celsius, and primers anneal.
4. Heat to 75 degrees Celsius, the optimum temperature for the thermostable polymerase III. This enzyme speeds up the annealing of primers