- Explain the Structure of DNA
Deoxyribonucleic Acid (DNA) is made out of sugars which are called deoxyribose, phosphates and nitrogen bases. this structure was founded in 1953 by Francis Crick and James Watson. DNA has 2 backbones, both formed by bonded sugar phospahte sections of adjacent nucleotides. the nucleotide bases face into a ladder which have rungs formed by H- bonds formed between base pairs. These base pairs are always found bonded with the same partner, purine bonds with pyrimidine, Adenine bonds with thymine and Guanine bonds with Cytosine. There are two strands in DNA, they are known as, Antiparallel and complimentary. Antiparallel strands are read in opposite directions and complimentary strands can give the same message.
2. How does this activity help model the structure of DNA? what changes could we make to improve the accuracy of this model?
I think this activity helps us understand what parts make up DNA strands and instead of just looking at a picture the model gives us a better understanding and a good visual. I think this activity was a good representation of DNA strands so I don’t think any changes would be needed.
3. when does DNA replication occur?
DNA replication is the process when a DNA strand duplicates itself. This occurs prior to cell division in a semi conservative process, each new strand contains one backbone from the original strand of DNA. Most importantly DNA replication occurs during mitosis, DNA is replicated during the Synthesis phase of interphase.
4. Name and describe three steps involved in DNA replication. Why dose this process occur differently on the “leading’ and “lagging” strands.
The three main steps include:
- Unwinding ans unzipping
- the helix unwinds
- the 2 strands unzip and h- bonds between the base pairs break
- DNA helicase enzyme causes unwinding
- Complimentary base pairing
- Nucleotides are always in the nucleus
- they move into place and form H- bonds with their partner strand
- this process is facilitated by DNA polymerase
- Joining
- on the new strand the nucleotides form covalent bonds
- leading strand: continuous DNA unzips
- Lagging strand: fragments form as DNA unzips DNA ligase glues the fragments together
This process occurs differently on the leading and lagging strands because they each have very different jobs the leading strand is continuous while the lagging strand is “picking up the pieces” and involves DNA ligase
5. What did you do the to the model to show the process better? In what ways was it inaccurate?
while making this model we twisted the DNA strand clockwise to represent an actual strand a bit better but overall it won’t look exactly because in real life they are much smaller and more put together since we only used pipe cleaners
