central dogma

Question 1

It outlines how DNA is transcribed into RNA, which is then translated into proteins, forming the basis for cellular function and heredity.

Answer 1

The Central Dogma of Molecular Biology

Question 2

○ Process by which DNA makes a copy of itself before cell division.
○ Involves enzymes like DNA polymerase.
○ Ensures genetic information is passed to daughter cells.

Answer 2

DNA Replication

Question 3

○ The process of synthesizing RNA from a DNA template.
○ RNA polymerase binds to the promoter region of a gene.
○ Produces messenger RNA (mRNA) that carries genetic information to
ribosomes.

Answer 3

Transcription

Question 4

○ The process where ribosomes synthesize proteins using mRNA as a template.
○ Involves transfer RNA (tRNA) bringing amino acids to the ribosome.
○ Codons on mRNA correspond to specific amino acids, forming polypeptide
chains.

Answer 4

Translation

Question 5

○ Includes folding, cleavage, phosphorylation, and glycosylation.
○ Essential for protein functionality and regulation.

Answer 5

Post-Translational Processing

Question 6

Translation Process (5)

Answer 6

1. initiation
2. elongation
3. translocation
4. termination
5. post-translation modifications

Question 7

○ Ribosome assembly on mRNA.
○ Start codon recognition (AUG).
○ tRNA carrying methionine binds to the start codon.

Answer 7

Initiation

Question 8

○ Sequential addition of amino acids to the growing polypeptide chain.
○ tRNA molecules bring specific amino acids to the ribosome based on
codon-anticodon pairing.
○ Peptide bonds form between adjacent amino acids.

Answer 8

Elongation

Question 9

○ Movement of the ribosome along the mRNA strand.
○ The ribosome shifts to expose the next codon for tRNA binding.
○ This process requires GTP as an energy source.

Answer 9

Translocation

Question 10

○ Occurs when a stop codon (UAA, UAG, UGA) is reached.
○ Release factors bind to the ribosome, prompting the release of the completed
polypeptide.
○ Ribosomal subunits disassemble from the mRNA

Answer 10

Termination

Question 11

○ Chemical modifications of the newly synthesized protein.
○ Includes phosphorylation, glycosylation, methylation, and cleavage.
○ These modifications are crucial for protein functionality, stability, and
localization.

Answer 11

Post-Translation Modifications

Question 12

Post-Translation Modifications (4)

Answer 12

1. phosphorylation
2. glycosylation
3. methylation
4. cleavage

Question 13

• synthesizes proteins by translating messenger RNA (mRNA) into polypeptide chains
• It consists of two subunits, each made up of ribosomal RNA (rRNA) and proteins, which work together during protein synthesis

Answer 13

Ribosome Structure

Question 14

In eukaryotes, the large subunit is ____ and the small subunit is ____; together
they form an ____ ribosome.

Answer 14

60S, 40S; 80S

Question 15

In prokaryotes, the large subunit is ___ and the small subunit is ___; together
they form a ___ ribosome.

Answer 15

50S, 30S; 70S

Question 16

○ The site where incoming aminoacyl-tRNA binds during translation.
○ Responsible for accepting new amino acids to be added to the growing
polypeptide chain.

Answer 16

A Site (Aminoacyl Site)

Question 17

○ The site where the tRNA carrying the growing polypeptide chain is located.
○ Facilitates the formation of peptide bonds between amino acids.

Answer 17

P Site (Peptidyl Site)

Question 18

○ The site where empty tRNA molecules exit the ribosome after their amino acid has been added to the polypeptide chain.
○ Plays a role in recycling tRNA for future rounds of translation.

Answer 18

E Site (Exit Site)

Question 19

• first step in gene expression, where a specific segment of DNA is copied into RNA by the enzyme RNA polymerase.
• involves several key elements and steps that ensure accurate synthesis of messenger RNA (mRNA) from the DNA template.

Answer 19

Transcription Process

Question 20

○ A specific DNA sequence located upstream of the gene.
○ Serves as the binding site for RNA polymerase and transcription factors.
○ Determines the start point for transcription.

Answer 20

Promoter Sequence

Question 21

○ Proteins that bind to specific DNA sequences near the promoter.
○ Help recruit RNA polymerase to the promoter region.
○ Regulate the efficiency and rate of transcription initiation.

Answer 21

Transcription Factors

Question 22

○ Formed when RNA polymerase binds to the promoter with the help of
transcription factors.
○ Marks the beginning of transcription.
○ Involves unwinding of the DNA double helix to expose the template strand.

Answer 22

Initiation Complex

Question 23

○ Specific sequences in the DNA that signal the end of transcription.
○ Causes RNA polymerase to detach from the DNA and release the newly
synthesized RNA molecule.
○ Ensures proper length and integrity of the mRNA transcript

Answer 23

Termination Sequence

Question 24

○ Modifications made to the primary RNA transcript before it becomes mature
mRNA.
○ Includes capping (addition of a 5’ cap), polyadenylation (addition of a poly-A
tail), and splicing (removal of introns).
○ Essential for stability, transport, and translation of mRNA.

Answer 24

Post-Transcriptional Processing

Question 25

• the biological process of producing two identical replicas of DNA from one original DNA molecule.
• essential for cell division and occurs in a highly regulated manner to ensure genetic fidelity.

Answer 25

DNA Replication

Question 26

Transcription Process (5)

Answer 26

1. Promoter Sequence
2. Transcription Factors
3. Initiation Complex
4. Termination Sequence
5. Post-Transcriptional Processing

Question 27

DNA Replication (6)

Answer 27

1. Prereplication Complex
2. Unwinding and Separation
3. Replication Bubble
4. Prevention of Tangling
5. Priming and Creation
6. Joining and Termination

Question 28

○ Formation of a complex at the origin of replication.
○ Involves various proteins that prepare the DNA for unwinding.

Answer 28

Prereplication Complex

Question 29

○ Helicase enzymes unwind the double helix structure.
○ Single-strand binding proteins stabilize separated strands to prevent
re-annealing.

Answer 29

Unwinding and Separation

Question 30

○ The area where the DNA strands are separated, creating a bubble-like structure.
○ Allows for simultaneous replication on both strands

Answer 30

Replication Bubble

Question 31

relieve torsional strain ahead of the replication fork

Answer 31

Topoisomerases

Question 32

Prevents supercoiling and tangling of DNA strands during replication

Answer 32

Prevention of Tangling

Question 33

○ RNA primers synthesized by primase provide starting points for DNA synthesis.
○ DNA polymerases extend the primers to create new DNA strands.

Answer 33

Priming and Creation

Question 34

In joining and termination, ______ fragments on the lagging strand are joined by DNA ligase.

Answer 34

Okazaki

Question 35

○ Replication terminates when the entire DNA molecule has been copied,
ensuring complete and accurate duplication

Answer 35

Joining and Termination