Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Genetic > Genetic Expression > Flashcards

Genetic Expression Flashcards

(71 cards)

Start Studying
1
Q

What is the building block of DNA?

A

Nucleotides

Ribose sugar+ nitrogenous base and phosphate group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Nucleotides are linked together by ——- bond

A

5’-3’ phosphodiester bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

——— and ——— outside structure and ——- stay inside

A

Sugar and phosphate ——> outside

Nitrogenous base

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Adenine and thymine pairs with ——— bond
Guanine and cytosine with ———

A

Two hydrogen bonds

Three hydrogen bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How does packaging of DNA in eukaryotes and prokaryotes take place ?

A

Eukaryotes - histone-DNA complex ( nucleosides )+ linker DNA between the nucleosomes

Prokaryotes - supercoiling the DNA

1 turn of the helix- normal 10 base pairs

Prokaryotes may underwound- more than 10 base pairs in 1 turn of helix

Prokaryotes may overwound- less than 10 base pairs in 1 turn of helix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

In the ——phase, DNA is the most compact

A

Metaphase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Euchromatin and heterochromatin

A

Euchromatin- less dense regions on the chromosomes

Heterochromatin- more dense regions such as centrosomes and telomere

Euchromatin allows the transcription processes from DNA to mRNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

DNA replicate in ——- manner

A

Semiconservative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

DNA replication stages

A

1 helicase breaks the DNA strand
2. SSB proteins keep the stands separated
3. To poison erase prevents overcoiling
4. Primase adds to the DNA strand to direct DNA polymerase
5. DNA polymerase constructs the DNA in 5’ to 3’ direction. So 3’—-> 5’ strand is the leading strand. 5’—>3’ strand is the lagging strand
6. Lagging strands require many primase enzymes to initiate the replication again and again——> result DNA fragments called Okazaki fragments are obtained.
7. Ligand enzyme filling the gaps between the Okazaki fragments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Every nitrogenous base contains———

A

Nitrogen. The more common one is 14N which is slightly lighter than the 15N

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

In prokaryotic replication, how many DNA polymerase are there ?

A

Two

Polymerase 3——> adds nucleotide to the growing strand
Polymerase 1- ——> replace the RNA primer with the DNA segments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Prokaryotic DNA replication starts at ———

A

Replication origin , proceeds in bidirectional

1 strand 3’——> 5 ‘ leading strand

Another direction ———> 5’ to 3’ ——-> lagging strand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Prokaryotes have multiple replication origin. T or F

A

False single only

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the function of topoisomerase in the prokaryotic division?

A

Prevent the supercoiling of DNA ahead of the replication.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

DNA polymerase 1 and ligase have the same func. T or F

A

False. DNA polymerase 1 ——> removes primers and replace it with DNA

Ligase——> Okazaki fragments on the lagging strands——. Filled with DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the func of sliding camp. Their shape?

A

Present on both leading and lagging strands. They hold DNA polymerase 3 as they are replicating . Keeps DNA polymerase from floating off. Sliding camp are the ring shaped proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Eukaryotes have multiple replicating origins. What are the differences compared to prokaryotes?

A

Prokaryotes —-> single circular chromosome
Eukaryotes —> multiple linear chromosome so can have multiple replicating origin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Why do telomere shorten as we age?

A

Telomerase enzymes are present only in germ cells and adult stem cells but not in somatic cells. So, there is a loss of DNA sequences in some regions as the cell divides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How many DNA polymerase enzymes are present in eukaryotes and prokaryotes

A

Eu- 14
Pol alpha, beta, gamma, delta and epsilon ko tone tl

Pro- 5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Are telomerase present in both prokaryotes and eukaryotes?

A

No , present only in eukaryotes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

RNA primer removal is carried out by ? In pro and eu

A

Eu-RNAase
pro-polymerase 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Major enzyme of DNA replication in eu and pro

A

Eu-leading - pol delta Lagging - pol epsilon
Pro- polymerase 3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Sliding camp is present only in prokaryotes

A

True, in eu an enz called PCNA is present

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Nucleoside is

A

The same structure with nucleotide but without phosphate group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
When DNA is replicated , how is it made sure to avoid mistakes to prevent from mutation?
1. DNA polymerase 3 proofread the complementary synthesized strand every time 2. Proofreading only after the whole process of replication ——> mix-match repair
26
Mutation may be ——— or ———
Spontaneous- naturally occurring in the body or induced- happens bcuz of the chemicals and external factors and UV light
27
Three types of mutation
Point mutation Silent mutation Substitution - transition - purine with purine pyrimidine with pyrimidine replacement - tranversion- purine with pyrimidine , pyrimidine with purine
28
Each amino acid can only represented by one codon
False. Each codon can represent one amino acid But amino acid eg, proline can be encoded by CCU, CCA, CCG, CCC
29
HIV has ——— enxyme
Reverse transcriptase enzyme RNA ——> DNA ——> mRNA ——> protein
30
Adenine on DNA is read ——— on RNA
Uracil
31
Stop codon
UGA, UAG , UAA U gyee ag U ag gyee U ag ag
32
Start codon is ——— and A/A is ———
AUG ——> methionine
33
Three properties of genetic code
1 universal ——> both eu and pro——> same codon= same amino acid 2. Degenerate or redundancy ——> only 20 A/A . But 64 codons present so, each amino acid can be represented by more than 3 codons 3. Ambiguous- each codon however can represent only one amino acid
34
Since genetic code is redundant, some amino acid can be represented by the same codon with a change in the last nucleotide ( eg, CCC——> CCG)- still represents proline.
True
35
AUG codon is near the ——- end 5’ or 3’
5’
36
DNA to mRNA is transcribed by ——— enxyme
RNA polymerase.
37
Both DNA replication and transcription of prokaryotes proceed in bidirectional?
False Replication- 2 directions Transcription - 1 strand of mRNA only used template strand ( 3’—>5’ stand ) bcuz RNA polymerase direction 5’—-> 3’ only
38
———- are the core of the RNA polymerase enz
Two alpha, beta and beta prime All the other subunits are known as holoenxymes
39
Promotor sequence where and what happens in prokaryotes
Promoter sequence —-> upstream of initiation start site They determine whether the transcription is happening all the time, some time or frequently Various promotor sequences may exist ——> most common are at -35 and 10 regions -35===> sigma binds and transcription is initiated (TTGACA sequence) -10====> DNA unwinds and mRNA’s phosphodiester bonds are made (TATAAT)
40
Elongation of prokaryotic DNA begins when ———
Sigma subunit released RNA polymerase transcribe the mRNA from DNA in 5’——> 3’ direction 40 nucleotides per second DNA has to be unwounded for the transcription to take place. This is done by RNA polymerase of prokaryotes . Base pairing between the template and new RNA strands are not strong enuf. So RNA polymerase acts as a stable linker so that elongation is not interrupted prematurely
41
Termination of prokaryotic transcription
2 types: rho dependent and rho independent Rho dependent——> mRNA encounters long run G nucleotides in the DNA template strand and it stalls the transcription + rho dependent tracks along and meet the former region===> termination Rho independent RNA polymerase encounters A-T rich regions on DNA so, it forms C-G rich regions on the new strand, —> as it elongates ——> hair pin like loop ——> stalls the transcription and begins to transcribe A-U rich region. Since A-U rich region weaker-===> it induces the core enz to break away and new strand is obtained
42
After the termination in prokaryotes ——— proceeds
mRNA degradation , translation occurs spontaneously bcuz there is no membrane bound nucleus in prokaryotes
43
The number of RNA polymerase and subunits in pro and eu
Pro——> one RNA polymerase ——> five subunits 2 alpha beta beta prime and sigma Eu——>3 RNA polymerase ——> subunits more than 14 Eu require transcription factors to initiate transcription
44
RNA polymerase —— the major transcription enzyme
2 They have transcription factors ( D, A, B ,F, E ,H)
45
Each eukaryotic mRNA is ——-, meaning they specify a single protein
Monogeni C
46
Eukaryotes require ——— to bind the RNA polymerase to the promoter region and to initiate transcription
Transcriptional factors
47
Promoter sequences are on ——— 1 DNA 2 RNA
1 DNA
48
Location and role of RNA polymerase 1, 2 and 3
RNA polymerase 1 Present in nucleolus Synthesize rRNA for ribosomes synthesis . They transcribe all the rRNA except 5S rRNA Polymerase 2 Located in the nucleus ——> responsible for transcribing pre-mRNAs Polymerase 3 Found in the nucleus ——> responsible for transcribing 5S rRNA, small nuclear RNAs
49
Func of small nuclear RNAs
Splicing of the introns fro pre mRNA——> mature mRNA
50
3 RNA polymerase in eukaryotes and their sensitivity to mushroom sensitivity
RNA pol 1- insensitive RNA pol 2- very sensitive RNA pol 3- moderately sensitive
51
The promoter sequence for eu RNA pol 2
TATA box located on the upstream and downstream of transcription start site
52
What are transcription factors and why are they needed?
Regulate the gene transcription Basal transcription factors func—> assemble the RNA polymerase 2 on the promoter sequence
53
Promoter sequence in RNA pol 1 and 3 TATA as pol 2?
No Pol1 ——> two C- G rich sequences in the -45 to -120 initiate the transcription but sequences from -180 to -105 upstream further enhance initiation Pol3—> upstream promoter or promoters within the genes transcribe mRNA
54
Termination of transcription in eu
Pol 2—> elongation takes place 1000- 2000 nucleotides beyond by the end of the gene being transcribed ——> for pol A tail which is removed during mRNA processing Pol1——> requires termination signals Pol 3—> hair pin like loop like rho independent termination
55
After the mRNA is transcribed in eukaryotes, the following process is ———
mRNA processing Transcription ends——> pre-mRNA RNA processing requires three steps 1. 5’ capping 2. 3’ Poly A tail 3. Splicing First mRNA is equipped with RNA stablizing proteins to prevent it from breakdown during the processing
56
What is 5’ capping
Adding the 7 methyl guanosine to the 5’ end Func- to initiate the translation and for the ribosomes to recognize translation start site
57
What is pre mRNA splicing ?
Pre mRNA after transcription contains introns + exons Only exons express and encode the functional proteins Introns must be removed all of them. If one remains——> it will disrupt in the protein synthesis ===> dysfunctional protein Splicing is carried out by spliceosomes,+ Small nuclear RNAs and complex proteins
58
Splicing occurs after mRNA leaves the nucleus . T or F
False. RNA is still in the nucleus
59
TRNA is synthesized in the ———
Nucleus
60
Pre rRNA and pre tRNA requires splicing like mRNA?
Yes. The only thing difference is that pre mRNA is bound with RNA stablizing proteins. Whereas tRNA and rRNA are bound with methyl group to prevent the breakdown
61
———- starts at AUG sequence
Translation
62
Protein synthesis requires energy
True Bcuz apart from water, protein ——> second major composition of the body
63
Ribosomes presence site in both eu and pro
Ribosomes can be in the cytoplasm, nucleus ( nucleolus) chloroplast, mitochondria , rough ER
64
Small subunits of pro and eu
Eu - 30S+50S = 70S Pro - 40S + 60S= 80S
65
TRNA needs——— to pair with correct amino acid
Aminoacyl tRNA synthase At least one aminoacyl tRNA synthase is present on the each amino acid Action of amino acyl tRNA synthase ATP——-> hydrolysis ——> AMP + P+P AMP-A/A===> activated amino acid——> tRNA expelled ——> activated amino acid is then transferred to tRNA
66
During the eukaryotic transcription elongation, how are chromosomes unwinded from his tone protein ?
FACT Facilitate chromatin transcription protein pull away the pre mRNA for transcription and reform nucleosomes afterwards
67
How is the translation initiated in bacteria?
Bacteria ‘s mRNA presents the Shine Dalgano sequence which the tRNA with the methionine binds and translation begins Small ribosomal subunit arrives first on the shine dalgano sequence which afterwards the large ribosomal subunit comes bind Sine dalgano sequence codes the start of each gene sequence , making the right Start codon of each gene
68
How does eukaryotic translation begin?
The complex of small rRNA and tRNA recognized the 5’ capping and find the AUG codon on the mRNA. It may not start translation at the first AUG sequence it sees. AUG codon must appear around a gene coding “ 5’gccRccAUGG” translation starts at the AUG sequence near the similar to that gene coding
69
Elongation of protein synthesis
Each 3 codons= 1 amino acid
70
How is the protein elongation terminated?
By three codons UGA, UAG, UAA Stop codons are recognized by proteins called release factors, they add water molecule to the last amino acid in a chain. This reaction separates chain from the tRNA and the newly made protein is released.
71
Post transitional modifications
Carboxyl end of amino acid—-> like a train ticket direct the translated proteins to targeted destination. The signalling molecule is usually clipped off after the transport

Genetic (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions