Chapter 16 Flashcards
1
Q
RNAi
A
- RNA interference
- Process whereby the expression of a gene is silenced by the presence of small double stranded RNA
2
Q
3 stages of gene expression
A
- replication
- transcription
- translation
3
Q
Replication
A
- the DNA replicates its information in a process that involves enzymes
4
Q
Transcription
A
- DNA codes for the production of messenger RNA (mRNA)
- In eukaryotic cells, the mRNA is processed and migrates from the nucleus to the cytoplasm
5
Q
Translation
A
- mRNA carries coded information to ribosomes
- Ribosomes “read” this information and use it for protein synthesis
6
Q
DNA to RNA
A
- transcription
- located in nucleus
7
Q
RNA to Protein
A
- translation
- located in the cytoplasm
8
Q
Stages- replication
A
- DNA duplicates
9
Q
Stages- Transcription
A
- RNA synthesis
10
Q
Stages- translation
A
- Protein synthesis
11
Q
Discovery of RNAi
A
- aim: overexpress Chalcone synthase (CHS)
- Method: incubated wild type petunias with plasmid DNA
- result: 42% of plants had leaves that were completely white or contained white patterns with purple
12
Q
Applications of RNAi
A
- biotechnology
- interrupt expression of specific genes
- therapeutic or medical applications
13
Q
Biotechnology
A
- RNAi can be used to create allergen free plants and fruits
- allergen free tomato generated by RNAi
14
Q
RNAI therapy
A
- used to treat diseases
- any disease or infection caused by: overproduction of a normal protein, production of an abnormal protein
15
Q
Diseases that benefit from RNAi
A
- Huntington’s disease
- Breast cancer
- ovarian cancer
- Frederick ataxia
16
Q
Obstacles faced by RNAi therapy (Know 3)
A
- delivery
- Stability
- specific targeting to disease response
- Activation of interferon response
- Saturation of RISC
- Persistence of silencing effects
17
Q
Administering RNAi for therapy
A
- extract stem cells
- genetically alter them with RNAi and then put them back in patients
- inhaling them for respiratory infections
- Inject directly to affected tissue
18
Q
Posttranscriptional Regulation
A
- Introns are spliced out of pre-mRNAs to produce the mature mRNA that is translated
- Alternative splicing recognizes different splice sites in different tissue types
- Mature mRNAs in each tissue posses different exons, resulting in different polypeptide products from the same gene
19
Q
Alternative Splicing
A
- many primer transcripts can be spliced in different ways to give rise to multiple mRNAs
20
Q
RNA editing
A
- creates mature mRNA that are not truly encoded by the genome
21
Q
Zinc finger motif
A
- DNA binding motif
- Location: Eukaryotic regulatory and other proteins
- Characteristics: Loop of amino acids with zinc at base
- Binding site of DNA: Major groove
22
Q
Leucine Zipper motif
A
- DNA binding motif
- Location: Eukaryotic transcription factor
- Characteristics: Helix of leucine and a basic arm
- Binding site: Two adjacent major grooves
23
Q
Helix loop helix motif
A
- DNA binding motif
- Location: Eukaryotic proteins
- Characteristics: Two alpha helices separated by a loop of amino acids
- Binding site in DNA: Major groove
24
Q
Eukaryotic DNA is packaged into
A
Chromatin
25
Q
How to control gene expression post transcriptionally?
A
- RNA interference
- alternative splicing
- RNA editing
- mRNA degradation
26
Q
two main types of RNAi
A
- microRNA (miRNA)
- Small interfering RNA (siRNA)
27
Q
siRNA
A
- targets specific gene
28
Q
miRNA
A
- rogue (target gene other than designed for)
29
Q
RISC
A
- RNA reduced silencing complex
30
Q
Similarity between miRNA and siRNA
A
- Same size (21-25 nucleotides)
