| how does sickle cell anemia form? what are its effects? | It forms upon a base substitution where instead of glutamic acid, valine is made as an amino acid. The red blood cells life span decreases and theyre less effective at carrying oxygen |
| what are some benefits of diploid cells? | More likely to avoid a recessive allele disease, and it adds hybrid vigor |
| when do chromosomes reach their minimum length? | metaphase |
| Compare chromosomes in eukaryotes and prokaryotes | Eukaryotes: two or more types of chromosome, associated to histone proteins, they have no plasmid, and it is linear DNA
Prokaryotes: only one type of chromosome, naked DNA, plasmid often present, and it is circular DNA |
| Discuss the idea that the more complex an organism the more chromosomes it has | It doesn't hold up when you compare a plant with an animal (plant in theory shouldnt have more), or also when you compare two animals of the 'same' complexity but they have an unequal amount of chromosomes. However it does make sense that the worm, arguably the least complex of all, has the smallest amount of chromosomes |
| Define the size of the genome | the amount of DNA molecules present in ONE chromosome of a species |
| What is autoradiography and how did John Cairns use it? | Autoradiography shows where radioactive atoms decay, and it can be used to show the position and length of DNA. John Cairns cultivated E. coli in radioactive thymine. He placed them on a membrane digested their cell walls so their DNA would spill into the membrane. He coated the membrane with photographic film and left it for two months. He was then able to see where its DNA was and he noticed it was circular |
| When and where does crossing over happen? | It happens in prophase I at the chiasma, which is where the non-sister chromatids exchange genetic information. |
| How many different combinations are possible during random orientation? | 2^23 |
| what factors promote genetic variation? | meiosis, fusion of gametes in sexual reproduction, and mutation |
| How does a trisomy occur, for example? | It happens due to non-disjunction, when chromosomes are or aren't pulled away so you have more, or less than you should. it could cause Down Syndrome or Klinefelter's |
| How do you retrieve cells for inspection in a karyogram? | through amniocentesis, or CVS sampling (placental tissue) |
| list some ways to know if a disease is autosomal, sex-linked, recessive or dominant | To see if it's sex-linked check the distribution pattern. If it is, it's dominant when it's passed down from father to daughter and recessive when it's from mother to son. If it's autosomal, it's recessive if the trait skipped generations, or if there are affected children with unaffected parents (means theyre carriers) |
| How is TAQ DNA polymerase prepared for PCR? | It's heated up to separate the DNA strands, then cooled down again so primers can bind next to the sequence to be copied, and then heated up again so taq polymerase can replicate the strands and make two copies from them |
| How is DNA profiling possible? what is STR | You replicate a sample of SRT through PCR and then visualize the pattern of that individual's DNA using gel electrophoresis. STRs are short repeated sequences of bases in a person's chromosome |
| How was Dolly made? | Somatic nuclear cell transfer. They took the nucleus out of an unfertilized egg and fused it with an udder cell of another sheep, then placed it in a surrogate mother. Dolly was identical to the sheep that gave the udder cell |
| Describe the procedure to make a recombinant plasmid | You extract mRNA de un pancreatic exocrine cell. Using reverse transcriptase you make a DNA copy of it, and sticky ends (G nucleotides) are added. Plasmid is cut open with restriction endonuclease and sticky C nucleotide ends are added to it. The DNA of both pancreatic cell and plasmid fuse through complementary base pairing. Ligase then seals the nicks in the recombinant plasmid and the latter is absorbed by the E. coli cell. E. coli is cultured in a fermenter and finally it starts producing human insulin which is then extracted |
| List pros and cons of Bt maize | Economic: (pro) higher crop yield (con) not all farmers would have access to the new technology and big companies would take over
Ecological: (pro) less land used for livestock, could be used for wildlife conservation (con) toxins could kill non-pest insects by falling on nearby plants
Human: (pro) less pesticide used, better for human health (con) some could be allergic to Bt maize |
