Genes and Protein Synthesis

Question 1

Central Dogma of Biology

Answer 1

This principle explains the flow of genetic information within a biological system. It describes the sequential process: DNA -> RNA -> Protein.
DNA is transcribed into RNA, and RNA is translated into proteins.

Question 2

Transcription

Answer 2

It occurs in the nucleus.
During transcription, RNA polymerase binds to a DNA template strand and synthesizes a complementary RNA molecule (mRNA) using nucleotides.

Question 3

Translation

Answer 3

This takes place in the cytoplasm on ribosomes.
During translation, ribosomes read the mRNA sequence, and tRNA molecules bring amino acids to the ribosome according to the codons on the mRNA, creating a polypeptide chain that forms a protein.

Question 4

mRNA (Messenger RNA)

Answer 4

Carries the genetic information from DNA to the cytoplasm/ribosome.

Question 5

rRNA (Ribosomal RNA)

Answer 5

Forms the structure of ribosomes and facilitates protein synthesis.

Question 6

tRNA (Transfer RNA)

Answer 6

Carries amino acids to the ribosome and matches them to the coded mRNA sequence during translation.

Question 7

Initiation

Answer 7

RNA polymerase binds to the promoter region of DNA, and the DNA strands unwind.

Question 8

Elongation

Answer 8

RNA polymerase moves along the DNA template, synthesizing mRNA by adding complementary RNA nucleotides.

Question 9

Termination

Answer 9

RNA polymerase reaches a terminator sequence, and transcription stops. mRNA is released.

Question 10

Processing

Answer 10

Pre-mRNA undergoes modifications like capping, splicing, and polyadenylation to form mature mRNA.

Question 11

Direction of Transcription

Answer 11

DNA → RNA is read in the 3’ to 5’ direction
RNA → Protein is read in the 5’ to 3’ direction

Question 12

Nucleotides

Answer 12

letters of the alphabet

Question 13

Codons

Answer 13

words (made of three letters, always)

Question 14

Ribosome Sites

Answer 14

Ribosomes move along mRNA, reading codons (sequences of three nucleotides). As the ribosome moves one codon, tRNA molecules bring amino acids corresponding to the codons.

Question 15

Anticodon

Answer 15

It’s a sequence of three nucleotides on tRNA that pairs with the mRNA codon during translation.

Question 16

Wobble Hypothesis

Answer 16

It suggests that the mRNA codon’s third base and the tRNA anticodon’s first base can exhibit some flexibility in base pairing, allowing one tRNA to recognize multiple codons.

Question 17

Lac Operon

Answer 17

In the presence of lactose, the lac operon allows the transcription of genes responsible for lactose metabolism. This happens because the lac repressor protein cannot bind to the operator due to lactose.

Question 18

Tryp Operon

Answer 18

It regulates the production of enzymes involved in tryptophan (amino acid) synthesis. When tryptophan levels are high, it binds to the repressor, activating it and preventing transcription.

Question 19

Small-Scale Gene Mutation

Answer 19

Point mutations (substitution, insertion, deletion) affecting one or a few nucleotides. (codons are made of three nucleotides)

Question 20

Large-Scale Gene Mutation

Answer 20

Deletions, duplications, inversions, or translocations affecting larger segments of DNA

Question 21

Identification

Answer 21

Mutation diagrams/examples can reveal changes in nucleotide sequences or chromosomal structures.

Question 22

Mutation Effects

Answer 22

Not all mutations are deleterious; some may be neutral or beneficial. However, mutations can lead to genetic disorders, cancers, or evolutionary changes.