Gene expression

Question 1

What is RNA processing?

Answer 1

Introns are removed then a Poly-A tail is added onto the 3’ while a methyl cap is added onto the 5’.

Question 2

What is the translation process?

Answer 2

The ribosome reads the mRNA 3 base pairs at a time called codons. tRNA brings in amino acids to produce a polypeptide chain.

Question 3

Protein synthesis

Answer 3

Once a polypeptide chain is made it is transferred to the endoplasmic reticulum where it is folded. From there it is transported via transport vesicles and moved into the Golgi apparatus, final protein modifications are then made such as attaching lipids to the protein.

Question 4

What is exocytosis?

Answer 4

In exocytosis, proteins are packed into secretory vesicles, which then fuse with the plasma membrane, they then release the proteins to the exterior of the cell.

Question 5

Properties of DNA

Answer 5

DNA contains the genetic codes for protein synthesis, genetic code is a universal triplet code that is degenerate, universal refers to the fact that all known organisms use the same generic code. Triplet refers to the fact that a sequence of three base pairs will code for one amino acid, and degenerate refers to the fact that one amino acid can code for more than one codon.

Question 6

What is the primary structure?

Answer 6

Is the specific sequence of amino acids as determined by the genetic code

Question 7

What is the secondary form?

Answer 7

The localised coiling and pleating, which is categorised into alpha helix, beta pleated sheeted and random coiling. The secondary structure comes from the interactions of the side chains of the amino acids (R group), the side chains have differing charges thus why interact differently.

Question 8

What is the tertiary form?

Answer 8

The overall folding (3D shape) of the polypeptides.

Question 9

What is the quaternery form?

Answer 9

Only a quaternary structure and a quaternary structure involve multiple polypeptide chains joining together to make a single functioning protein.

Question 10

Amino Acid Structure

Question 11

What happens when amino acids bond?

Answer 11

When amino acids bond with each other they produce h20 this is because the hydrogen and oxygen are lost from the carboxyl group, and then the amino and carboxyl groups are called peptide bonds.

Question 12

Prokaryotic

Answer 12

They have the identifying feature of lacking a nucleus, instead, they store their DNA in the cytosol and because of this transcription and translation can occur simultaneously which allows for the regulation of genes/operons.

Answer 13

Prokaryotes organise their DNA into operons, operons have an operator region a promoter region a leader region and multiple structural genes, and when being transcribed and translated all the structural genes in the operation are transcribed and translated together, the structural genes in operons do not have introns and exons because transcription dn transcription occurs simultaneously, therefore there is no time for the mRNA to undergo RNA processing, instead they have operating and leader region to have an alternate form of regulation of the genes. These f

Question 14

Benefits to regulation

Answer 14

Benefits of regulation include saving energy, producing different products at different stages, and producing different products based on organisms.

Question 15

What happens when you regulate with a repressor protein when theres high tryptophan in the enviroment?

Answer 15

Tryptophan binds to a repressor protein, then the active repressor protein binds to the operator region of the operon. The repressor prevents RNA polymerase from binding to the promoter. No gene expression occurs during this process because there is no initiation of transcription.

Question 16

What happens when you regulate with repressor protein when there is low tryptophan in the environment?

Answer 16

The repressor becomes inactive because it is no longer bound to the operator. Thus this allows for RNA polymerase to bind to the promoter which causes transcription of the operon to occur, this is when gene expression happens.

Question 17

What happens when you regulate via attenuation and there are high levels of tryptophan?

Answer 17

It stops the completion of transcription, this is a mechanism used to reduce the expression of the trp operon. High tryptophan leads to fast translation, and then a terminating hairpin forms, after RNA polymerase detaches causing transcription to stop.

Question 18

What is step one in the transformation of bacteria?

Answer 18

Identify, isolate and amplify, primers are designed to attach top the ends of the gene of interest, thus allowing for that part of the DNA to be amplified. Restriction enzyme cut sites can be added on to the end of the gene of interest to allow complementary cuts sites to match plasmids.

Question 19

What happens when you regulate via attenuation and there are low levels of attenuation?

Answer 19

Low tryptophan causes a slow translation, an anti-terminator hairpin then forms and transcription continues thus causing the operon to be translated.

Question 20

What is step 2 in transformation of bacteria?

Answer 20

Create a recombinant plasmid, cut the gene of interest with restriction enzymes and cut the plasmid with the same restriction enzyme. Works best with two different enzymes (this ensures correct orientation fo gene), sticky ends also improve the efficiency, this also allows for natural complementary base pairing. Plasmid must contain an antibiotic resistance gene and may contain reporter gene for selection of colonies. Then you add DNA ligase to create phosphodiester bonds between the sugar-phosphate backbone of the gene of interest and the plasmid.

Question 21

What is step 3 in transformation of bacteria?

Answer 21

Calcium chloride, transformation is when plasmids are moved into the bacteria. Calcium chloride binds to the membrane and is positively charged, plasmids that are negatively charged are attracted to the positive charge and move towards the membrane of the bacteria.

Question 22

What is step 4 in transformation?

Answer 22

The heat shock step opens pores in bacterial plasma membrane and allows plasmids to enter, then you incubate it on ice to close pores in bacterial membrane keeping the plasmids inside.

Question 23

What is the final step in transformation?

Answer 23

Plate the bacteria onto agar plates, then we allow them to recover and then once they have been growing for long enough we will conduct screening and selection of successful transformants, these are the bacteeria that have taken up the plasmids of interest we do that by using antibiotics and out reporter genes.

Question 24

DNA structure

Answer 24

Sugar phosphate backbone
Double-stranded
Deoxyribose sugar
A,T,C,G

Question 25

RNA structure

Answer 25

Single-stranded
Ribose sugar
Sugar phosphate backbone
A,U,G,C
mRNA
rRNA
tRNA

Question 26

What is mRNA

Answer 26

Messenger RNA, is a molecule that carries genetic information from the DNA in the cell nucleus to the ribosomes in the cytoplasm.

Question 27

What is rRNA

Answer 27

This is a type of RNA molecule that forms an integral part of the ribosome, the cellular organelle responsible for protein synthesis.