Biology: DNA and Protein Synthesis Quiz

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Questions and Answers

What is the role of the start codon AUG in protein synthesis?

It pairs with the tRNA anticodon to bring the correct amino acid to the ribosome.

It codes for the amino acid methionine and signals the start of protein synthesis. (correct)

It helps to break down the mRNA strand after protein synthesis is complete.

It signals the end of protein synthesis.

What is the function of transfer RNA (tRNA) during translation?

tRNA carries the genetic code from the DNA to the ribosome.

tRNA acts as a template for protein synthesis.

tRNA helps to break down the mRNA strand after protein synthesis is complete.

tRNA brings the correct amino acid to the ribosome based on the mRNA codon. (correct)

What is the name of the process where the genetic information from DNA is copied into a new molecule of messenger RNA (mRNA)?

Transcription (correct)

Mutation

Replication

Translation

What is the main difference between gene mutation and chromosomal mutation?

Gene mutation involves changes in the DNA sequence of a single gene, while chromosomal mutation affects the structure or number of chromosomes. (D) Signup and view all the answers

Which of the following is NOT a type of chromosomal mutation?

Replication (B) Signup and view all the answers

What is the specific chromosomal abnormality that causes Cri du chat syndrome?

Deletion in the part of the short arm of chromosome 5 (C) Signup and view all the answers

What is the name of the syndrome that is characterized by a deletion in the terminal portion of chromosome 11q?

Jacobsen Syndrome (C) Signup and view all the answers

What is the chromosomal abnormality associated with Klinefelter's Syndrome?

XXY (A) Signup and view all the answers

Which of the following is NOT a common characteristic of Down Syndrome?

Increased muscle tone (B) Signup and view all the answers

Which of the following syndromes is associated with a bleeding disorder called Paris-Trousseau syndrome?

Jacobsen syndrome (C) Signup and view all the answers

What is the chromosomal basis of Turner's Syndrome?

XO (C) Signup and view all the answers

Which of the following is an example of a mutagen?

Sunlight (B) Signup and view all the answers

Which of the following best describes the process of translocation in chromosomal mutations?

A section of DNA is moved to a different chromosome. (B) Signup and view all the answers

In the context of DNA replication, what is the main function of RNA polymerase?

It synthesizes a new RNA strand complementary to the template DNA strand. (A) Signup and view all the answers

What is the function of the stop codons UAG, UAA, and UGA in protein synthesis?

They signal the end of protein synthesis. (A) Signup and view all the answers

What is the difference between a codon and an anticodon?

A codon is a sequence of three nucleotides in mRNA, while an anticodon is a sequence of three nucleotides in tRNA. (D) Signup and view all the answers

What is the primary function of RNA polymerase in transcription?

Creating a copy of the DNA sequence in mRNA (C) Signup and view all the answers

Which of the following best describes the process of DNA replication?

Two identical copies of the DNA molecule are produced. (D) Signup and view all the answers

What is the role of Helicase in DNA replication?

Unwinding the double helix of DNA (D) Signup and view all the answers

Why is DNA replication referred to as semi-conservative?

Because only half of the original DNA molecule is used in the new strand. (D) Signup and view all the answers

Which nitrogenous base is found in RNA but not in DNA?

Uracil (A) Signup and view all the answers

Which of the following is NOT a type of RNA?

hnRNA (A) Signup and view all the answers

What is the main difference between DNA and RNA?

DNA is a double helix, while RNA is single-stranded. (D) Signup and view all the answers

What is the central dogma of molecular biology?

The flow of genetic information from DNA to protein. (C) Signup and view all the answers

Study Notes

DNA and Protein Synthesis

DNA and RNA are the two main genetic materials in living organisms.
DNA is a double helix composed of deoxyribonucleotides, while RNA is single-stranded.
RNA types include mRNA (messenger), rRNA (ribosomal), and tRNA (transfer).
DNA base pairs: Guanine (G) with Cytosine (C), Adenine (A) with Thymine (T).
RNA base pairs: Adenine (A) with Uracil (U), Guanine (G) with Cytosine (C).
DNA holds the genetic information for all biological structures and functions.
The Central Dogma explains the flow of genetic information in biological systems (DNA to RNA to protein).

DNA Replication

DNA replication is the process of making identical copies of a double-stranded DNA molecule.
It ensures genetic information is passed on.
Steps of replication:
- DNA strands separate (Helicase breaks hydrogen bonds).
- RNA primers bind to the DNA strands.
- DNA nucleotides are added to the template strands (using DNA Polymerase).
- Two identical DNA molecules are formed (semiconservative).

Transcription

Transcription is the process of copying a DNA segment (gene) into mRNA.
mRNA carries the genetic information from the nucleus to the cytoplasm.
Steps of transcription:
- RNA polymerase binds and unzips the DNA.
- RNA polymerase adds RNA nucleotides complementary to the DNA strand.
- mRNA separates from the DNA, which reforms.
- mRNA moves to the cytoplasm.

Translation

Translation is the process of converting the mRNA sequence into a protein.
Ribosomes read mRNA in codons (3 bases at a time).
Each codon codes for a specific amino acid.
Steps of translation:
- mRNA binds to a ribosome.
- tRNA molecules, carrying amino acids, approach the ribosome.
- tRNA anticodon pairs with mRNA codon (initiation complex).
- Amino acids are linked together by peptide bonds.
- The process continues until a stop codon is reached.
- Polypeptide chain (protein) is released.

Mutations

Mutations are changes in DNA sequence.
Mutations can affect organism growth and development.
Mutagens (e.g., harmful chemicals, radiations) cause mutations.
Mutations can be in reproductive (heritable) or somatic cells.
Types of mutations:
- Gene mutations (changes within genes):
  - Deletion (loss of DNA segment).
  - Duplication (extra copies of gene/chromosome).
  - Translocation (chromosome segments exchange position).
  - Inversion (chromosome segments reverse position).
- Chromosomal mutations (changes in chromosome structure).

Examples of Chromosomal Disorders

Cri du chat syndrome: Deletion in chromosome 5; high-pitched cry, characteristic facial features, intellectual disability.
Down syndrome (Trisomy 21): Extra copy of chromosome 21; decreased muscle tone, heart defects, intellectual disability.
Edward syndrome (Trisomy 18): Extra copy of chromosome 18; severe intellectual and motor disability, multiple congenital anomalies, short lifespan.
Jacobsen syndrome (11q deletion): Rare disorder; variable intellectual ability, speech problems, bleeding disorder.
Klinefelter syndrome (XXY): Male disorder; underdeveloped sexual characteristics, tall stature, possible speech delay.
Turner syndrome (XO): Female disorder; underdeveloped sexual characteristics, short stature, low hairline, possible heart and kidney problems.

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Description

Test your knowledge on DNA and protein synthesis, including the structure of DNA and RNA, their respective functions, and the process of DNA replication. This quiz covers fundamental concepts such as the Central Dogma and the roles of different RNA types in genetic information flow.