Chapter 3: Nucleic Acid Structure and Function Flashcards
What is a genome?
The collection of genes in an organism
How condensed are chromosomes in interphase vs mitosis
Chromosomes are less condensed in interphase
Most condensed in mitosis for proper segregation
What is Euchromatin and heterochromatin and what are their functions
Euchromatin: Gene rich regions that need too be loose to allow access
Heterochromatin: regions of non coding DNA usually packed together
Describe the structure of a prokaryote gene
A promoter that binds a RNA polymerase through coding sequences resulting in RNA that can be used to make one(monocistronic) or many (polycistronic) proteins
Describe the structure of a eukaryote gene
- A promoter binds a RNA polymerase that starts at a 5’ UTR and goes toward the 3’ UTR and makes a transcript
- The transcript then has a 5’ cap and poly(A) tail added and the introns are removed
- The mature RNA then is translated by a ribosome making a protein
What is Alternative splicing and what is its purpose
When an RNA transcript is partially translated by different ribosomes meaning not all exons are included in the mRNA synthesis. This results in proteins that serve a similar function
What is HGPS?
A mutation resulting in rapid aging in children that is not inherited as the child dies too early to pass it on. 1 in 4 mil. is caused by a base change resulting in lamina build up on membrane which results in premature cell death
What is a plasmid?
- A self replicating piece of circular DNA
- Carry genetic info not found in chromosomal DNA
- Found in prokaryotes and Eukaryotes
- Can be cloned, conjugated, transformed, or transduced
What is cDNA and how is it made
DNA made complimentary to mRNA using reverse transcriptase
1. Primer added to mRNA poly A tail
2. Reverse transcriptase
3. Ribonuclease denatures mRNA
4. DNA poly used to make complimentary
5. DNA ligase fills in primers
What is the Sanger technique and how was it used
Uses fluorescent labeled ddNTPs, DNA primer, DNA poly, and DNA strand to sequence DNA. ddNTPs are added at the 3’ end and then detected by a laser that analyzes fluorescence
What is PCR? At what rate does it work? What are the Phases and what materials are needed?
-Polymerase Chain Reaction
- 2^n each cycle
- Denature, Anneal, Elongation
- Target DNA, Primers, NTP’s, DNA polymerase
What is CRSPR-Cas9? How does it work?
A form of adaptive immunity against bacteriophage viruses that targets specific DNA
- Cas9 introduced via plasmids
- Cas9 cleaves target DNA
- Non homologous end joining
- Gene knockout
- Homology directed repair causes gene knock-in
- Can contain auto florescent protein to make identifying specific strand easier
Draw a deoxyribose and ribose sugar
What are the similarities and differences between DNA and RNA
DNA only:
- Double helix (antiparallel strands)
- Thymine
- Deoxyribose
- Stable
- Long lived
RNA only:
- Single stranded
- Uracil
- Ribose
- Ribozymes
- Unstable (due to cleaving)
- Short lived
Both:
- Adenine, Cytosine, Guanine
- Structure is nucleotides, phosphorus and sugar
- 5’ to 3’
What structural differences are there between A, B, and Z DNA
A:
- Right handed
- Helical structure
- Tightly packed
B:
- Right handed
- Helical structure
- Most stable
Z:
- Left Handed
- Zig-Zag arrangement
