Lecture 8 and 9: DNA and RNA

Question 1

Aneuploidy

Answer 1

• presence of one or more extra chromosomes or the absence of one or more chromosomes.
• can occur by mitosis or meiosis or crossover during metaphase

Question 2

Karyotypes

Answer 2

-is a test to identify and evaluate the size, shape, and number of chromosomes in a sample of body cells. Extra or missing chromosomes, or abnormal positions of chromosome pieces, can cause problems with a person’s growth, development, and body functions

Question 3

DNA Ligase

Answer 3

seals DNA (okazaki) fragments on lagging strand
-repairs and joins together two DNA strands

Question 4

DNA polymerase

Answer 4

repairs gaps between Okazaki fragments

• responsible for DNA replication
• needed so the cells DNA can duplicate
• Deoxynucleotide polymerization

Question 5

DNA primase

Answer 5

Initiates synthesis of RNA primers

Question 6

Topoisomerases

Answer 6

relieves torsional strain that results from helicase

Question 7

Helicase

Answer 7

unwinds dna strands which forms replication fork( two DNA strands ripped apart)
-ATP driven

Question 8

Synthesis of a new DNA strand is written in which of the following direction

Answer 8

B. 5’ to 3’

Question 9

Types of DNA Damage

Answer 9

Replication-Natural

Question 10

Trisomy 21

Answer 10

• Extra chromosome on 21

- Down syndrome

Question 11

Diploid

Answer 11

Two sets of genetic info
- one maternal, one paternal
23 sets-> 46 chromosomes

Question 12

RNA

Answer 12

• ribose sugar
• has uracil
• single stranded
• is a complementary copy of DNA
• made in shorter units than DNA

Question 13

Cyclic nucleotides

Answer 13

play an important role in cell signaling

Question 14

ATP

Answer 14

Adenosine 5 Triphosphate

Question 15

Purines

Answer 15

• Have two rings

- A and G

Question 16

Pyrimidine

Answer 16

• Have one ring

- C, G and U

Question 17

Nucleoside

Answer 17

Base+Sugar

Question 18

Nucleotide

Answer 18

Base+Sugar+Phosphate

Question 19

Which of the following statement is correct? Ribose and deoxyribose are present in mammals in a:
A. D‐beta configuration?
B. L‐beta configuration?C. D‐alpha configuration?
D. L‐alpha configuratio

Answer 19

A. D‐beta configuration?

D-sugars are in the body

Question 20

Transcription

Answer 20

DNA -> RNA

-carried out by RNA polymerase

Question 21

tRNA

Answer 21

Transfer RNA

Links mRNA to amino acid

Question 22

miRNA

Answer 22

inhibit/modulates translation

–Transcribed from DNA

Question 23

snRNA

Answer 23

intron removal

Question 24

RNA Polymerase

Answer 24

• Starts copying template strand
• no proofreading
• DOES NOT participate in mRNA splicing

Question 25

Translation

Answer 25

mRNA to protein

Question 26

Splicing

Answer 26

Introns are removed and exons are spliced together

Question 27

Rifamycin group

Answer 27

inhibit RNA synthesis by targeting RNA polymerase

Question 28

Coding Strand

Answer 28

5' to 3'

Question 29

Template Strand

Answer 29

3' to 5'

Question 30

IncRNA

Answer 30

regulate mRNA and gene | transcription via RNA Pol II

Question 31

DMD

Answer 31

Exon is deleted which is a mutation that abolishes expression of dystrophin which is an essential protein that maintains muscle fiber integrity

Question 32

Ribose

Answer 32

ribonucleic acid

Question 33

Deoxyribose

Answer 33

deoxyribonucleic acid | - lacks oxygen on the 2' carbon

Question 34

In DNA A pairs with____ | and G pairs with ____

Answer 34

T C

Question 35

How many copys of genetic info do we have?

Answer 35

two

Question 36

Is all DNA in one linear strand?

Answer 36

No we have chromosomes

Question 37

How do we go from meters of DNA to microns?

Answer 37

Histones → nucleosomes

Question 38

DNA replication – S phase

Answer 38

- Requires several origins of replication -Occurs from ssDNA template - Requires RNA primer to initiate replication - is directional - Requires ligation of individually copies and re-condensation into chromatin structure

Question 39

Okazaki fragments

Answer 39

- Lagging ( 3' to 5') | - Leading strands ( 5' to 3')

Question 40

Polymerase can only make new DNA

Answer 40

in the 5’-3’ direction from a 3’-5’ template

Question 41

DNA replication in eukaryotic cells

Answer 41

1. Binding of initiator proteins 2. Binding of DNA Helicase 3. Loading DNA Helicase onto DNA strand 4. DNA helicase unwinds the DNA double strand 5. RNA primer syntheis enables DNA polymerase to start first DNA chain 6 Formation of replication forks

Question 42

Single-strand binding proteins (SSBs)

Answer 42

- Prevent premature reannealing of daDNA

Question 43

Spontaneous/endogenous DNA damage

Answer 43

– Deamination – Oxidation (ROS) – Methylation

Question 44

Exogenous DNA damage

Answer 44

– UV radiation – Ionizing radiation – Drugs and environmental exposure

Question 45

In RNA

Answer 45

no primer is needed compare to in DNA replication | - no proofreading

Question 46

Coding strand ATGATCTCGTAA -> mRNA

Answer 46

AUGAUCUCGUAA

Question 47

Coding strand ATGATCTCGTAA -> template strand

Answer 47

TACTAGAGCATT

Question 48

Endogenous

Answer 48

having internal cause or origin

Question 49

Endogenous RNA

Answer 49

miRNA snRNA IncRNA

Question 50

Rifamycin group: Rifampin, Rifabutin, Rifapentine

Answer 50

Inhibit RNA synthesis by targeting RNA polymerase.

Question 51

Transcription begins when

Answer 51

RNA polymerase binds to a so-called promoter sequence on the DNA molecule - They express genes at different times -> development, differentiation, adaptation

Question 52

Mechanisms regulating gene expression

Answer 52

* Gene amplification * Gene rearrangment * RNA processing * Alternate mRNA splicing * Transport of mRNA from nucleus to cytoplasm * Regulation of mRNA stability * Compartmentalization * ncRNA silencing and activation

Question 53

mRNA processing and splicing – Intron removal

Answer 53

1. Primary transcript 2. Nucleophilic attack at 5' end of intron 3. Lariat formation 4. Cut at 3' end of intron 5. Ligation of 3' end of exon 1 to 5' end of exon 2

Question 54

Which of the following statement about RNA polymerase complex is false? RNA polymerase A. binds to the promotor region on the DNA strand B. participates in mRNA transcription C. participates in mRNA elongation D.participates in mRNA splicing

Answer 54

D.participates in mRNA splicing

Question 55

From a gene to a protein | • mRNA → proteins through

Answer 55

* Initation * Elongation * Termination Requires: • mRNA • tRNA • rRNA

Question 56

What would be the anticodon for the start codon AUG?

Answer 56

UAC

Question 57

Codon is read | Anti-codon is read

Answer 57

5' to 3' AUG mRNA | 3' to 5'. UAC

Question 58

Translation initiation

Answer 58

``` - mRNA must associate with rRNA • Location “start” codon (AUG) = codon • Matched to AUC on tRNA = anticodon • Attached to methionine • Amino acid chain begins ```

Question 59

Elongation

Answer 59

* “Read” mRNA in sets of 3 NA = codon * Growing chain in P-site; amino acid added in A site, then shift down * Repeat until reach codon with “empty” anti-codon/tRNA

Question 60

Termination

Answer 60

• Chain elongation will stop when tRNA associating lacks an amino acid

Question 61

miRNA are also transcribed from

Answer 61

DNA (specific genes encoding for miRNA)

Question 62

Transcription takes place in ____ where translation takes place in ____

Answer 62

Nucleus | RIbosome

Question 63

Which of the following statements about miRNA is correct? A. miRNAs are transcribed from RNA B. miRNAs are transcribed from DNA C. miRNAs are involved in mRNA splicing D. miRNAs are involved in DNA transcription

Answer 63

B. miRNAs are transcribed from DNA

Question 64

Duchenne Muscular Dystrophy (DMD)

Answer 64

an X-linked genetic disease and one of the most severe form of muscular dystrophy - 1 in 5,000 male births - is due to missense mutations in the dystrophin gene abolishing expression of the dystrophin, an essential protein that maintains muscle fiber integrity

Question 65

Phosphorodiamidate Morpholino Oligomer (PMO) | A Promising Drug to Treat DMD

Answer 65

exon skipping therapy - In frame – mRNA translated, Truncated protein product