Central Dogma of Molecular Biology

Question 1

What is a gene ?

Answer 1

The recipe to make a protein

Question 2

Where are genes found ?

Answer 2

They are found in DNA

Question 3

What is a chromosome ?

Answer 3

A full length DNA molecule

Question 4

What is a chromatid ?

Answer 4

DNA stored in a highly compact state

Question 5

What is a species’ genome ?

Answer 5

The complete set of all its chromosomes

Question 6

What are “house-keeping genes” ?

Answer 6

Genes that encode proteins needed in all cells (such as actin and tubulin)

Question 7

What are histones ?

Answer 7

Sphere-like, positively charged proteins found in the nucleus

Question 8

What is the role of histones ?

Answer 8

To help sort out DNA

To maintain an organised structure

Question 9

Where are proteins produced ?

Answer 9

In the cytosol

On the rougth ER

Question 10

What concepts form the Central Dogma of Molecular BIology ?

Answer 10

Transcription
Translation
Replication

Question 11

What is transcription ?

Answer 11

The production of mRNA by using a DNA template

Question 12

What is mRNA ?

Answer 12

An intermidiate copy of a gene that can be taken out of the nucleus

Question 13

What is RNA polymerase ?

Answer 13

An enzyme that catalyses the formation of phosphodiester bonds between nucleotides

Question 14

In what direction are phosphodiester bonds formed ?

Answer 14

Only in a 5’-to-3’ direction

Question 15

In what direction does RNA plolymerase move along the template strand ?

Answer 15

In a 3’-to-5’ direction

Question 16

What is the template strand ?

Answer 16

The DNA strand on which the RNA polymerase attaches

Question 17

What is the terminator region ?

Answer 17

The transcription end site, where RNA polymerase will stop transcription

Question 18

What is the promoter region ?

Answer 18

A part of a DNA molecule that allows RNA polymerase to arrive and begin transcription more quickly

Question 19

What is the enhancer and repressor regions ?

Answer 19

Regions in the DNA that help or deter the recruitment of RNA polymerase

Question 20

What changes does the mRNA must undergo before being allowed to leave the nucleus ?

Answer 20

The addition of a 5’ cap and a 3’ polyA tail

Splicing

Question 21

What is splicing ?

Answer 21

The removal of introns

Question 22

What are introns ?

Answer 22

Unnecessary regions of the mRNA (consistuted of non-coding nucleotides)

Question 23

What is alternative splicing ?

Answer 23

When an intron is left behind

When some of the coding part of the mRNA is removed

Question 24

What is the consequence of alternative splicing ?

Answer 24

Different mRNA are produced from the same gene, which leads to different proteins being made

Question 25

What is a mature mRNA ?

Answer 25

A mRNA that is ready to leave the nucleus

Question 26

What is translation ?

Answer 26

The process of changing from nucleotide "langage" to amino acid "langage"

Question 27

What is a codon ?

Answer 27

A set of three nucleotides that is translated into a single amino aicd

Question 28

What is one of the challenges of translation ?

Answer 28

There are only four nucleotides, but 20 amino acids

Question 29

What is the redundancy or degeneracy of the genetic code ?

Answer 29

The fact that different codons can code for the same amino acid

Question 30

What does the tRNA (transfer RNA) ?

Answer 30

It is responsible for linking a specific codon to the corresponding amino acid

Question 31

What is a charged tRNA ?

Answer 31

A tRNA attached to the right amino acid

Question 32

What does aminoacyl tRNA synthesase ?

Answer 32

It attaches the amino acid to the tRNA

Question 33

What does the ribosome during translation ?

Answer 33

It catalyses the formation of peptide bonds It regulates when translation of a specific mRNA is needed It determines where on the RNA translation must take place

Question 34

Of what is made the ribosome ?

Answer 34

``` Proteins Ribosomal RNA (rRNA) ```

Question 35

What are the three steps of translation ?

Answer 35

Initiation Elongation Termination

Question 36

What is initiation?

Answer 36

THe step at which translation is the mos carefully reviewed and regulated (Happens BEFORE translation starts)

Question 37

What is elongation ?

Answer 37

The systematic occurance of translation (the actual process)

Question 38

What sites does the ribosome have ?

Answer 38

The A-site (amino acid site) THe P-site (polypeptide site) THe E-site (exit)

Question 39

WHat is the A-site ?

Answer 39

The site where the charged tRNA arrives

Question 40

What is the P-site ?

Answer 40

The site where a tRNA with a full chain of the polypeptide "rests"

Question 41

What is the E-site ?

Answer 41

The site where the empty tRNA is ejected

Question 42

What is termination ?

Answer 42

The recruitment a of release factor to end translation

Question 43

WHat is a release factor ?

Answer 43

A protein that is similar to tRNA that is recruited when a codon for "stop" is read.

Question 44

What are the differences between prokaryotes and Eukarytoes for those two processes ?

Answer 44

In prokaryotes: Transcription and translation take place in the cytosol No changes made to the mRNA after transcription Polycistronic

Question 45

What does polycistronic mean ?

Answer 45

A mRNA that has more than one gene on it. (by comparison, eukaryotes are monocistronic)

Question 46

What is replication ?

Answer 46

The process during which DNA produces a complete copy of itself

Question 47

What is DNA polymerase ?

Answer 47

The enzyme that catalyses the formation of a new copy of DNA

Question 48

In what direction does DNA polymerase move ?

Answer 48

In a 3'-to- 5' direction

Question 49

Why is replication called a "semi-conservative model" ?

Answer 49

Because after the passage of DNA polymerase, the two DNA strands won't reattach. They both will be paired up with a new strand (daugther strand)

Question 50

What is the replication fork ?

Answer 50

The point at which the two DNA stands separate

Question 51

What is the leading strand ?

Answer 51

The continuous "round " of replication

Question 52

What is the lagging strand ?

Answer 52

The discontinuous "round " of replication