LESSON_ CENTRAL DOGMA PROTEIN SYNTHESIS

Question 1

Describes the flow of genetic information in cells from DNA to
messenger RNA (mRNA) to protein. It states that genes specify the sequence of mRNA molecules, which
in turn specify the sequence of proteins. Because the information stored in DNA is so central to cellular
function, the cell keeps the DNA protected and copies it in the form of RNA. An enzyme adds one nucleotide to the mRNA strand for every nucleotide it reads in the DNA strand. The translation of this
information to a protein is more complex because three mRNA nucleotides correspond to one amino acid in the polypeptide sequence.

Answer 1

Central Dogma of Molecular biology

Question 2

Meaning of DNA

Answer 2

Deoxyribonucleic (Sugar component) acid

Question 3

Is the genetic material of all organisms on Earth from microbes
to plants and human beings. An organism’s complete set of DNAs, including all its genes is called the genome.

Answer 3

DNA (Deoxyribonucleic acid)

Question 4

Contains a complete set of information which determines inherited physical characteristics
such as height, skin, eye, and hair color and many others.

Answer 4

genome

Question 5

The DNA is a thin long molecule found in the cell’s nucleus which is made up of ____________

Answer 5

Nucleotides

Question 6

Basic structure of Nucleotides

Answer 6

Phosphate Group
Sugar
Nitrogenous base

Question 7

4 types of nucleotides base and its pairs

Answer 7

adenine- thymine
guanine- cytosine

Question 8

DNA molecules fold in paired packages called ___________ that are stored in the nucleus of the Cell.

Answer 8

Chromosomes

Question 9

Worked out that DNA is a double helix which appears like a staircase

The sides of the double helix structure are the sugar phosphate backbones,

and the steps are the base pairs

Answer 9

James Watson and Francis Crick

Question 10

The process of DNA duplication from an existing DNA.

Is important for the growth repair and reproduction of cells of an organism.

This process occurs in the nucleus
of eukaryotic cells before a cell divides by mitosis of meiosis.

When a cell divides, each resulting cell keeps a copy of all your chromosomes.

Answer 10

DNA Replication

Question 11

The major key players in DNA Replication are the Enzymes…

Answer 11

helicase
primase
DNA polymerase
ligase

Question 12

The unzipping enzyme

Unzips the two stands of DNA in the double helix through the hydrogen bond that holds the two base pairs together

Answer 12

Helicase

Question 13

Will initialize the process and directs the DNA polymerase for it to figure out where it gets to start.

Answer 13

Primase

Question 14

The starting point for DNA
synthesis.

Are made of RNA (Ribonucleic Acid).

Its major role is to act as a messenger
carrying instructions from DNA for controlling the synthesis of proteins.

Answer 14

Primer

Question 15

Is the builder enzyme which replicates DNA molecules in order to build a new strand of DNA.

Answer 15

DNA polymerase

Question 16

Is the gluer.

Which helps glue DNA fragments together to form the new strand of DNA.

Answer 16

Ligase

Question 17

Three major steps of DNA replication

Answer 17

Initiation
Elongation
Termination

Question 18

DNA replication starts at the Origin of Replication.

The unzipping enzyme Helicase causes the DNA strand separation, which leads to the formation of the replication fork.

It breaks the hydrogen bond between the base pairs to separate the strand, thus separating the DNA into individual strands.

Answer 18

Initiation

Question 19

DNA Polymerase III makes the new DNA strand by reading the nucleotides on the template strand and binding one nucleotide after the other to generate a whole new complementary strand.

It helps in the proofreading and repairing the new strand.

DNA Polymerase is able to identify and back track any mis-paired nucleotides and correct it immediately.

The bases attached to each strand then pair up with the three nucleotides found in the cytoplasm. If it finds an Adenine (A) on the template, it will only add a Thymine (T). If it finds a Guanine (G) on the template, it will only add a Cytosine (C).

Answer 19

Elongation

Question 20

In the previous steps of DNA replication, at the Origin, a Primer helps the DNA Polymerase to
initiate the process.

As the strand is created, the primer has to be removed.

This is when DNA Polymerase It comes into the picture to replace the RNA nucleotides from the Primer with DNA nucleotides to make sure
it is DNA all the way through.

When DNA Polymerase III adds nucleotides to the lagging strand and forms Okazaki fragments, it leaves a gap or two between the fragments.

These gaps are filled by the enzyme
ligase and make sure that everything else is connected.

Answer 20

Termination

Question 21

The Replication Process is considered complete

Answer 21

Once all the Primers are removed and Ligase has filled in all the remaining gaps between the Okazaki Fragments.

Question 22

Name of your ORIGINAL and REPLICATE DNA

Answer 22

Template DNA and Complement DNA

Question 23

Meaning of RNA

Answer 23

Ribonucleic Acid

Question 24

RNA falls into three major categories

Answer 24

Messenger RNA (mRNA)
Transfer RNA (tRNA)
Ribosomal RNA (rRNA)

Question 25

Copies the genetic code from the DNA into a form that can be read and used to make proteins.

Transmits genetic information from the nucleus to the cell’s cytoplasm.

Answer 25

Messenger RNA (mRNA)

Question 26

Is situated in the cytoplasm of a cell, where we can find the ribosomes.

Leads the translation of mRNA
into proteins.

Answer 26

Ribosomal RNA (rRNA)

Question 27

Transfers amino acids to the ribosome that matches each three-nucleotide codon of rRNA.

The amino acids then can be combined and processed to make polypeptides and proteins.

Answer 27

Transfer RNA (tRNA)

Question 28

Is the process where RNA is made from the DNA by copying the base sequence of the double stranded DNA into a piece of a single stranded nucleic acid.

This process is catalyzed by the enzyme RNA Polymerase.

Answer 28

Transcription

Question 29

Takes place in the cell’s nucleus. This process uses DNA as a model to make an RNA (mRNA) molecule.

During transcription, a strand of mRNA is made that corresponds to a strand of DNA.

Just like DNA replication, this process also occurs in three major steps: initiation, elongation, and termination.

Answer 29

Transcription

Question 30

Is the start of transcription. It transpires when the enzyme RNA polymerase binds to a specific region of a gene which is called the promoter with the help of proteins called ‘transcription factors’.

This signals the DNA double strand to unwind and open so the RNA polymerase enzyme can read the bases found in one of the DNA strands.

With the open strands, one is considered as the template strand (anti-sense strand) and this will be used to generate the mRNA.

The other is called the non-template strand (sense strand).

After reading the bases, the RNA polymerase enzyme is now ready to make a strand of mRNA with a complementary sequence of bases.

Answer 30

Transcription: Initiation

Question 31

Is the adding of nucleotides to the mRNA strand. RNA polymerase reads the opened DNA strand and forms the mRNA molecule with the use of complementary base pairs.

There is a short time during this process when the newly formed RNA is bound to the opened DNA.

During this process , an adenine (A) in the DNA binds to an uracil (U) in the RNA. RNA polymerase does not need a
primer during this process. It simply initiates the mRNA synthesis from the starting point and then moves
downstream reading the anti-sense strand from 3’ to 5’ and generating the mRNA from the 5’ to 3’ end as it goes.

Unlike helicase enzymes in DNA replication, RNA polymerase zips DNA back up as it goes keeping only 10-20 bases exposed one at a time.

Answer 31

Transcription: Elongation

Question 32

Is the last step of the transcription process. This happens when RNA polymerase enzyme reaches a stop or termination sequence in the gene.

When the stop sequence or stop codon is reached, the enzyme detaches from the gene. The mRNA strand is now produced, and it detaches from DNA.

It carries with it the information encoded in the gene.

Answer 32

Termination

Question 33

Is the final process of protein synthesis that takes place in the cytoplasm.

The genetic information of the DNA is used as the origin to form messenger RNA (mRNA) by the transcription process.
The single stranded mRNA then serves as a template during translation.

Ribosomes are the facilitators of the translation process in the cytoplasm. Ribosomes induce the binding of complimentary transfer RNA (tRNA) anticodon sequences to the mRNA. The tRNAs contain particular amino acids linked together by the
ribosome.

During this process, the mRNA sequence is decoded to produce a specific amino acid chain called the polypeptide. Folding of the polypeptide produces an active protein which is able to perform important functions within the cell.

Answer 33

Translation

Question 34

Proteins may generally have globular or fibrous structure depending on its
particular role in the bodily functions

Answer 34

Protein Structure

Question 35

Spherical, compact and soluble protein’s

Answer 35

globular Protein

Question 36

Elongated and insoluble

Answer 36

Fibrous protein

Question 37

Protein building block

Answer 37

Amino Acids

Question 38

The Amino acids are grouped as:

Answer 38

Essential and Non- Essential

Question 39

Are those which the human body is capable of synthesizing

Answer 39

Non- essential amino acids

Question 40

Must be obtained from the diet

Answer 40

Essential amino acids

Question 41

Proteins are synthesized in the human body through a process called translation.

Occurs in the cytoplasm and involves converting genetic codes into proteins.

Genetic codes are assembled during
DNA transcription, where DNA is decoded into RNA.

Cell structures called ribosomes then help transcribe RNA into polypeptide chains that need to be modified to become functioning proteins.

Answer 41

Translation

Question 42

Key components required for translation

Answer 42

mRNA, tRNA, ribosomes and aminoacyl tRNA synthetases

Question 43

Is a complex organelle, present in the cytoplasm, which serves as the site of action for protein synthesis.

It provides the enzymes needed for peptide bond formation. The nucleotide sequence in mRNA is recognized in triplets, called codons.

Moves along the single strand mRNA, and when a complimentary codon sequence belonging to amino acid bearing tRNA bonds with the mRNA, the amino acid is added to the chain.
The mRNA possesses a stop codon, a sequence of three nucleotides that indicates that translation is complete.

Upon reaching the stop codon, the ribosome ceases translation and releases the mRNA and
newly generated polypeptide.

Answer 43

Ribosome

Question 44

Is used to convey information from DNA to the ribosome. It is a single strand molecule, complimentary to the DNA template, and is generated through transcription.

Strands of mRNA are made up of codons, each of which signifies a particular amino acid to be added to the polypeptide in a certain order.

Must interact with ribosomal RNA (rRNA), the central component of ribosomal machinery that recognizes the start and stop codons of mRNA, and transfer RNA (tRNA), which provides the amino acid once bound with a complimentary mRNA codon.

Answer 44

Messenger RNA (mRNA)

Question 45

This is a single strand of RNA composed of approximately 80 ribonucleotides.

Each tRNA is read as a ribonucleotide triplet called an anticodon that is complementary to an mRNA codon.

Carries a particular amino acid, which is added to the growing polypeptide chain if complimentary codons bond.

Answer 45

Transfer RNA (tRNA)

Question 46

These are enzymes that link each amino acid to their corresponding tRNA with the help of a two-step
process.

Each amino acid has a unique synthetase and the active site of each enzyme fits only one specific
combination of the amino acid and tRNA.

Answer 46

Aminoacyl tRNA synthetases