BIO 243 LAB FINAL EXAM- UNIVERSITY OF
CALGARY WINTER 2024 WITH COMPLETE
SOLUTION
What is DNA? Ans✔✔- DNA is a biomolecule which contains the genetic blueprint for all living organisms.What is the DNA chain made of? What are the parts? Ans✔✔- The DNA chain is made of deoxyribonucleotides. The three parts are N-bases, sugar, and phosphate group(s).Name the pyrimidines. How many ring structures do they have? Ans✔✔- Thymine and Cytosine. They are single ring structures.Name the purines. How many ring structures do they have? Ans✔✔- Adenine and Guanine. They are double ring structures.How many hydrogen bonds does adenine and thymine have? Ans✔✔- Two How many hydrogen bonds does cytosine and guanine have? Ans✔✔- Three Through which bond are the P-group and the N-base bonded to the sugar? and on which carbon?Ans✔✔- Through covalent bonding. For the N-base, it bonds onto the C-1' and for the P- group, it bonds onto the C-5'.Which bond joins the two strands of DNA together? Ans✔✔- Hydrogen bonds What does one nucleotide consist of? Ans✔✔- A sugar, one base, and a phosphate group.What is the phosphodiester bond? Characteristics? Direction? Ans✔✔- It is when deoxyribonucleotides get joined together through covalent bonds. It goes from 5'-3', and you add new nucleotides to the 3' 1 / 2
end of the previous nucleotide present in the DNA chain. It is important for DNA replication to start, and is catalyzed by DNA polymerases.What is the external structures of the DNA responsible for? Ans✔✔- DNA synthesis, gives a framework for supporting the overall structure of the DNA molecule.What is the internal structures of the DNA responsible for? Ans✔✔- Storage of genetic information in the N bases, central dogma.What does the DNA polymerase do? Ans✔✔- Takes a single nucleotide from the template strand and creates complementary nucleotides.How is the antiparallel nature of DNA made? Ans✔✔- It is a result of the hydrogen bonding interactions between the nitrogen bases. It occurs when a base has to pair itself with another base at the 3' end, which is opposite.What is the anti conformation of DNA? Ans✔✔- When the rotation around the covalent bond between the nitrogen base and sugar cause the nitrogen base to lie flat, instead of being upright.How does DNA fit into a nucleus in eukaryotes? Ans✔✔- It wounds itself around positively charged histone proteins and helps fold DNA into chromatin.In order to extract the DNA from the strawberry, we added detergent (NaCl). Why? Ans✔✔- The detergent consists of Na+ and Cl-. The Na+ reacts with the negatively charged DNA, whereas the Cl- reacts with the positively charged histones to neutralize that interaction, and release the DNA.Why was isopropanol added to the solution, containing strawberry and detergent? Ans✔✔- Since the DNA was present at the same time as sodium, and since both are highly soluble in water (both being polar), it was added to decrease that polarity (make it less soluble in water), making DNA easier to extract.Why did we use strawberries in the lab? Ans✔✔- They contain many copies of chromosomes; polyploidy (more than two paired homologous chromosomes), compared to humans that are diploid.Also, the more amount of DNA makes it easier to extract.
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