cell biology transcription

Question 1

the expression of genes into proteins involves 2 processes:

Answer 1

transcription and translataion
( the regulation occurs at each step as:
1- chromatin structure
2- transcription initiation
3- mRNA stability
4- trasncriptiing processing )

Question 2

when cell needs to produce certain proteins , it activates the region of the genome encoding for that protein and produces —- copies of that dna in the form of —–

Answer 2

• multiple
• mRNA

Question 3

multiple copies of —- are used to translate the genetic code into protein aka the photocopy portion of the cell through the action of the cells protein manufacturing machinery called —-

Answer 3

• mRNA
• ribosomes

Question 4

—– expands the quantity of a given protein and it gives an important control point for regulating when and how much proteins gets made

Answer 4

mRNA

Question 5

• important for copying the genetic info from dna ( primary a storage form of the genome )
• contributes to the formation of ribosomes ( ribosomes are particles important for the sythesis of new proteins )
• help assemble new polypeptides by bringing individuals amino acids ( tRNA )
  are all fucntions for —–

Answer 5

RNA

Question 6

rna is — stranded of 2/3degree structure and is found in —— and the sugar is —- while dna is only found in —-

Answer 6

• single stranded
• nucleas and cytoplasm
• ribose sugar
• nucleas

Question 7

—– is a type of rna that codes for proteins when produced by transcprtion , is translated m contains instruction for protein scythes and is found in nucleus and cytoplasm

Answer 7

mrna

Question 8

—- is a type of rna that form a basic structure of the ribosome and catalyse protein sythesis

Answer 8

rRNA

Question 9

—- is a type of rna by which it function in variety of nuclear process including splicing the pre-mrna

Answer 9

snRNA ( small nuclear rna )

Question 10

—- type of rna that function in variety of diverse cellular process including regulation of gene expression , x- chromosome inactivation and protein transport

Answer 10

ncRNA ( non coding rna)

Question 11

transcription begins at the —- at the end of the —- region , trancrption ends at the —– site

Answer 11

• transcription start site ( TSS)
• promoter region
• termination site

Question 12

—- are regions of the dna upstream of the TSS which lead the initiation of transcpriton , each gene has a unique one and the 2 different types are:

Answer 12

• promotors
• basal promotor and enhancer element

Question 13

—- recognised by the proteins that will aid transcription ( aka transcription factors )

Answer 13

enhancer

Question 14

— bound by a key transcriptional enzyme rna polymerase II and basal transcription factors required ( which is required for rna pol II bidding )

Answer 14

basal

Question 15

—– essential for trancpriton of all genes and fucntions recruit in RNA pol II , binds basal/general trancripton factors first and these once are bound to en pol II will bind . example:

Answer 15

• basal promotor
• TATA box which is common ( 20-30 base pairs from transcriptional start site and can bind basal Tfs and RNA pol II )

Question 16

—- is a process by which the info in a strand of dna is copied into a new molecule of messenger rna ( mRNA )

Answer 16

transcpriton
( process:
1- transcription by which exons are protein coding and introns are non coding
2- trancirption processing
3- splicing
4- protein transaltion )

Question 17

transcpriton is catalysed by —- which this enzyme transcribes just one of the 2 dna strands of the gene reading the template —- direction and making and rna copy —- direction
it incorporates ——- when creating mrna copy of the dna

Answer 17

• rna polymerase II
• 3’-5’
• 5’-3’
• NTP ( nucletodietriphosphate aka a,g,u,c )

Question 18

three stages of tracnription :
1- in initiation the —– binds to the dna and unwind 17-18 bp segment of the —–
2- in elongation the —– moves along the — sytheisinf dna until it reaches the ——- . during this phase an area of the dna under the rna poly II remains — this —– moves along the dna
3-in termination the transcription continues beyond the —– , it recruits the —– enzyme that cleaves mRNA which is 20 bases —- beyond the sequence

Answer 18

• rna polymerase II
• promoter aka the open complex
• rna poly ii
• template
• termination region
• unwound
• transcription bubble
• protein encoding region 3’UTR ( untranslated region )
• endonuclease
• downstream

Question 19

true or false:
in termination most eukaryotic mRNA precursors have the motif AAUAAA within the transcribed sequence = polyadenylation signal sequence

Answer 19

true

Question 20

in post transcriptionl mrna processing:
the rna molecule sythesies by the rna pol II is called —- and the collection of these precursors molecules is known as —-
extensive modification in:

Answer 20

-primary 1 degree transcript
-heterogeneous nuclear rna ( hnRNA)
- 5’ capping and 3’ poly A tail

Question 21

—- is the addition of the 6-methyl-guanosine residue .
the function of this capping is the protection of the mRNA from degradation of the exonuclease , promotes nuclear export and aids recognition by the translational machinery

Answer 21

• 5’ capping

Question 22

after the polyadenylation signal sequence has been —- which is the —- , —- is recruited and cleave —- , then the poly A polymerase then add 40-250 adenine residues to the cleaved —– end

Answer 22

• recognised
• AAUAAA
• endonuclease
• mrna
• 3’end

Question 23

mRNA from different genes have their longevity encoded within them the — sequence determines the stability of the mRNA and the destabilizing of this sequence target for —— and the — protects from the degradation

Answer 23

• 3’ UTR
• endoculease
• 5’cap

Question 24

—— confers mRNA stability

Answer 24

poly A tail

Question 25

gene transcribed to produce mRNA with both --- and ---- the ---- only encode the protein coding region of the mrna must be processed before translated

Answer 25

- exons and introns - exons

Question 26

the main areas of post transcprtional regualtion are:

Answer 26

- mrna stability - differential mrna splicing

Question 27

the non coding intronic sequence are not presented in ---- they are spliced/cut our and adjacent --- are joined together,

Answer 27

- mature rna - exons

Question 28

1-the splicing is Carrie out by molecular machine known as ---- as its a large complex consisting od ------ 2- small nuclear RNA combine w number of proteins to form ---- which facilitate splicing by recognising and interacting w specific sequence at each end of the intron , cutting and rejoining the rna 3- splicing occurs releasing the ---

Answer 28

- splicisomes - proteins and rna - snRNA - introns

Question 29

we need to turn genes on and off to genrate ---- as every cell has the same dna content bu differentiate into different cells

Answer 29

- specify

Question 30

---- genes are involved in metabolism/dna repair , regulating transcription and translation and they are always being made

Answer 30

- constitutive gene

Question 31

----- are only syethsied when required and it determines the development and tissue specificity and allows the cells to respond to the environment as: hormones m cytokines , cell-cell interaction

Answer 31

inducible gene

Question 32

1- transcpriton can be activated in a ----- 2- ---- always on and level of gene expression is determined by how many ---- and how much --- around 3- --- turned on when needed and determines the tissue specificity

Answer 32

- constitutive or inducible - consitive - binding sites - tf - inducible

Question 33

---- are proteins that bind specific dna sequence in the gene promoter , it controls the --- of the transaction , 100s of different transcpriton factors each recognise unique dna sequence , it also interacts w rna pol II

Answer 33

- transaction factors - rate

Question 34

the number of ------ for the transcrption factor in the promoter region determines the --- of the transcprion

Answer 34

- binding sites - rate

Question 35

---- allows only genes that are required to be switched on , allows rapid and dynamic response to stimulus , specific regulation of adjoining regions of dna

Answer 35

inducible tf

Question 36

----- are small strands of rna that regulate dene expression (20-25 nucleotide ) , transcribed from the dna but non coding aka they don't make proteins , partially complimentary to the number of mRNA aka the protein coding ones , primary function is to down regulate gene expression

Answer 36

microRNA , miRNA

Question 37

how does miRNA block gene expression ? 1- promotes rna --- and binds complementary sequence in the ---- UTR which induces degradation 2- binds --- and blocks ----

Answer 37

- degradation - 3' - mrna - translation

Question 38

true or false: - non coding dna is known as junk dna - only 2% of human genome makes protien - 205 is the elements required for gene expression as introns , promoters , enhancers

Answer 38

- true - false , 1% - true