Molecular Biology Quiz: Chromatin and DNA

<p>The winding of DNA around histone proteins. (A)</p> Signup and view all the answers

<p>Histone H5 (A)</p> Signup and view all the answers

<p>To serve as the genetic material for inheritance (B)</p> Signup and view all the answers

<p>They identified nucleic acid as the cause of transformation. (B)</p> Signup and view all the answers

<p>It must be stable over time and faithfully replicated. (D)</p> Signup and view all the answers

<p>They demonstrated that DNA is responsible for transferring genetic information. (A)</p> Signup and view all the answers

<p>Its high molecular weight and acidity. (D)</p> Signup and view all the answers

<p>To provide a stable structure for gene storage. (D)</p> Signup and view all the answers

<p>They address fundamental societal issues requiring genetic solutions. (D)</p> Signup and view all the answers

<p>Professor of Human Immunogenetics (A)</p> Signup and view all the answers

<p>West African and Finnish populations (B)</p> Signup and view all the answers

<p>Double helix (D)</p> Signup and view all the answers

<p>Ribose (B)</p> Signup and view all the answers

<p>The polarity of the strands (D)</p> Signup and view all the answers

<p>Sugar and base (D)</p> Signup and view all the answers

<p>Sugar-phosphate groups (C)</p> Signup and view all the answers

<p>Hydrogen bonds (D)</p> Signup and view all the answers

<p>It highlighted genetic variations lacking representation in earlier studies. (A)</p> Signup and view all the answers

<p>Antiparallel to each other (C)</p> Signup and view all the answers

<p>20 Å (D)</p> Signup and view all the answers

<p>Hydrogen bonding between complementary bases (D)</p> Signup and view all the answers

<p>She used X-ray crystallography to study the structure of DNA. (C)</p> Signup and view all the answers

<p>His comments regarding race and intelligence (D)</p> Signup and view all the answers

<p>Thymine (B)</p> Signup and view all the answers

<p>Two (D)</p> Signup and view all the answers

<p>Adenine and Thymine (C)</p> Signup and view all the answers

<p>X-ray crystallography (D)</p> Signup and view all the answers

<p>In a male-dominated lab (C)</p> Signup and view all the answers

<p>Hydrogen bonds between complementary base pairs (B)</p> Signup and view all the answers

<p>Adenine and Thymine (C)</p> Signup and view all the answers

<p>It ensures that base pairing is complementary and stable (D)</p> Signup and view all the answers

<p>It is carried in the sequence of nitrogenous bases (D)</p> Signup and view all the answers

<p>3 hydrogen bonds (B)</p> Signup and view all the answers

<p>It consists of four possible bases (D)</p> Signup and view all the answers

<p>Able to control metabolic processes (A)</p> Signup and view all the answers

<p>To maintain structure and stability (B)</p> Signup and view all the answers

<p>It involves the disruption of hydrogen bonds between base pairs (B)</p> Signup and view all the answers

<p>Controlled changes in genetic sequences (D)</p> Signup and view all the answers

<p>DNA contains deoxyribose, which is more stable than ribose (A)</p> Signup and view all the answers

<p>It removes non-coding sequences from pre-mRNA (A)</p> Signup and view all the answers

<p>It describes the flow of genetic information as DNA to RNA to protein (C)</p> Signup and view all the answers

<p>By using protein complexes that bind to RNA molecules (D)</p> Signup and view all the answers

<p>Exposure to radioactive uracil (A)</p> Signup and view all the answers

<p>RNA is composed of ribonucleotides containing ribose sugar (D)</p> Signup and view all the answers

<p>The recruitment of ribosomal subunits and the formation of the start codon complex (D)</p> Signup and view all the answers

<p>Small nuclear RNA molecules (A)</p> Signup and view all the answers

<p>Same gene producing multiple mRNA transcripts (B)</p> Signup and view all the answers

<p>To mark mature and intact mRNA for export (A)</p> Signup and view all the answers

<p>95% (B)</p> Signup and view all the answers

<p>They are broken down and nucleotides are reused (B)</p> Signup and view all the answers

<p>Transport genetic instructions to ribosomes (D)</p> Signup and view all the answers

<p>DNA is transcribed into RNA (B)</p> Signup and view all the answers

<p>Uracil replaces thymine in base pairing (C)</p> Signup and view all the answers

<p>The synthesis mechanism of RNA and DNA (A)</p> Signup and view all the answers

<p>RNA contains ribose, whereas DNA contains deoxyribose (D)</p> Signup and view all the answers

<p>It allows selective expression of genes for protein production (D)</p> Signup and view all the answers

<p>mRNA serves as the template for protein synthesis, while tRNA brings amino acids to the ribosome (C)</p> Signup and view all the answers

<p>Translation of mRNA into protein (C)</p> Signup and view all the answers

<p>DNA polymerase and RNA polymerase (A)</p> Signup and view all the answers

<p>RNA contains ribose with a 2' OH group. (B)</p> Signup and view all the answers

<p>RNA is largely single-stranded but may form base pairs. (A)</p> Signup and view all the answers

<p>mRNA (D)</p> Signup and view all the answers

<p>RNA Polymerase II (C)</p> Signup and view all the answers

<p>Catalyzing biochemical reactions. (D)</p> Signup and view all the answers

<p>It is a major component of ribosomes. (D)</p> Signup and view all the answers

<p>Its single-stranded nature allowing base pairing. (D)</p> Signup and view all the answers

<p>It helps in the assembly of amino acids into proteins. (C)</p> Signup and view all the answers

<p>RNA contains a 2' OH group while DNA does not. (B)</p> Signup and view all the answers

<p>The presence of ribose sugar. (C)</p> Signup and view all the answers

<p>5’ to 3’ direction (B)</p> Signup and view all the answers

<p>Ribonucleotide triphosphates (D)</p> Signup and view all the answers

<p>Capping with an atypical nucleotide (D)</p> Signup and view all the answers

<p>To enhance mRNA stability (A)</p> Signup and view all the answers

<p>Adding a 3' cap with a conventional nucleotide (D)</p> Signup and view all the answers

<p>Phosphodiester bonds between nucleotides (B)</p> Signup and view all the answers

<p>It is lost as energy is released (B)</p> Signup and view all the answers

<p>Non-coding sequences in genes (B)</p> Signup and view all the answers

<p>One strand runs 5’ to 3’ and the other runs 3’ to 5’ (D)</p> Signup and view all the answers

<p>It catalyzes the formation of phosphodiester bonds (D)</p> Signup and view all the answers

<p>3 nucleotides (C)</p> Signup and view all the answers

<p>Transcription (A)</p> Signup and view all the answers

<p>It is universal across all organisms. (A), It consists of continuous sequences without punctuation. (C), It is triplet-based and degenerative. (D)</p> Signup and view all the answers

<p>He identified the order of nucleotides in nucleic acids. (A)</p> Signup and view all the answers

<p>They require less time and resources to develop. (B), They do not involve the traditional methods of vaccine development. (D)</p> Signup and view all the answers

<p>Khorana and Nirenberg (C)</p> Signup and view all the answers

<p>Translation (C)</p> Signup and view all the answers

<p>Insufficient combinations exist. (C)</p> Signup and view all the answers

<p>To decipher the codons of mRNA (B)</p> Signup and view all the answers

<p>E-site (B)</p> Signup and view all the answers

<p>It consists of codons that specify amino acids (C)</p> Signup and view all the answers

<p>It plays a role in the initiation and regulation of translation (A)</p> Signup and view all the answers

<p>It combines with proteins to form the structural core of ribosomes (C)</p> Signup and view all the answers

<p>It reads the mRNA in sets of three nucleotides (codons). (A)</p> Signup and view all the answers

<p>Stop codons signal the termination of protein synthesis. (A)</p> Signup and view all the answers

<p>Multiple tRNAs can correspond to a single amino acid. (A)</p> Signup and view all the answers

<p>Mitochondrial genetic material. (C)</p> Signup and view all the answers

<p>Marshall Nirenberg and Har Gobind Khorana. (A)</p> Signup and view all the answers

<p>The genetic code is universal but some variations exist. (C)</p> Signup and view all the answers

<p>tRNAs help in reading the codons and delivering the correct amino acids. (D)</p> Signup and view all the answers

<p>Analyzing protein sequences digitally using bioinformatics. (B)</p> Signup and view all the answers

<p>It signifies that the same codons usually encode the same amino acids across species. (A)</p> Signup and view all the answers

<p>There are 64 different codons for 20 amino acids. (C)</p> Signup and view all the answers

<p>Each nucleotide is part of only one codon. (D)</p> Signup and view all the answers

<p>Recombination testing. (D)</p> Signup and view all the answers

<p>It intercalates and can lead to insertions or deletions. (A)</p> Signup and view all the answers

<p>Frameshift mutation. (C)</p> Signup and view all the answers

<p>THE BIG RED FOX ATE THE EGG (C)</p> Signup and view all the answers

<p>Recombined mutants can produce pseudo-wild type forms. (B)</p> Signup and view all the answers

<p>They still exhibited a mutant phenotype. (A)</p> Signup and view all the answers

<p>They suggest a lethal mutation in the rII region. (D)</p> Signup and view all the answers

<p>It leads to insertions or deletions of bases. (C)</p> Signup and view all the answers

<p>Carries genetic information from DNA to ribosomes (B)</p> Signup and view all the answers

<p>Identifies specific amino acids and matches them with mRNA codons (B)</p> Signup and view all the answers

<p>It enables a tRNA to tolerate certain mismatches at the codon position (D)</p> Signup and view all the answers

<p>By aminoacyl-tRNA synthetases during a process called charging (B)</p> Signup and view all the answers

<p>rRNA (A)</p> Signup and view all the answers

<p>Aminoacylation (D)</p> Signup and view all the answers

<p>It contains an amino acid binding site (B)</p> Signup and view all the answers

<p>Attaching amino acids to tRNA molecules (D)</p> Signup and view all the answers

<p>The anticodon loop (B)</p> Signup and view all the answers

<p>Synthetases link amino acids to their specific tRNAs (A)</p> Signup and view all the answers

The study of genes, genetic variation, and inheritance in organisms.

The molecule responsible for storing and transmitting genetic information in living organisms.

The process by which DNA replicates itself, ensuring that each new cell receives a complete copy of the genetic information.

The process by which genetic information encoded in DNA is used to synthesize proteins, which carry out various functions in the cell.

Changes or alterations in the sequence of DNA, which may be beneficial, harmful, or neutral.

The organized structure of DNA and associated proteins within the nucleus of eukaryotic cells. They carry genetic information in the form of genes.

The study of how genes interact with each other and with the environment to influence traits and disease.

DNA, the molecule of life, is shaped like a twisted ladder or spiral staircase.

X-ray crystallography is a technique that uses the diffraction pattern of X-rays to determine the arrangement of atoms in a molecule. Rosalind Franklin used this technique to capture images of the DNA molecule.

The two strands of DNA are held together by complementary base pairs. Adenine (A) pairs with thymine (T), and guanine (G) pairs with cytosine (C).

James Watson and Francis Crick are credited with proposing the double helix model of DNA. They used Rosalind Franklin's X-ray diffraction images and other research to build their model.

The Watson-Crick model of DNA explains how genetic information is stored and passed on from one generation to the next.

Rosalind Franklin's work played a crucial role in the discovery of DNA's structure, but her contributions were not fully recognized at the time. She died tragically at a young age, before the Nobel Prize was awarded to Watson, Crick and Wilkins.

Watson's controversial views on race and intelligence led to his suspension from his position at Cold Spring Harbor Laboratory in 2007.

This refers to false scientific claims made to support bias against a particular race or group.

A type of diabetes that affects how the body regulates blood sugar levels. It is more common in West African populations compared to Finnish populations.

Variations in DNA sequence among individuals or populations.

The study of how genes influence the immune system's function and response to pathogens.

A branch of biology that studies the complete set of genes and their interactions within an organism.

A complex molecule that carries genetic information in the form of a double helix structure.

A repeating unit in DNA consisting of a sugar molecule, a phosphate group, and one of four nitrogenous bases.

The two strands of DNA run in opposite directions, with one strand running 5' to 3' and the other 3' to 5'.

The process of acquiring, testing, and analyzing DNA samples from individuals.

The process of making copies of DNA, ensuring that each new cell receives a complete copy of genetic information.

A collection of DNA samples from individuals representing various populations.

DNA is not a straight line but is twisted into a spiral shape, like a ladder that's been twisted.

The two strands of DNA are held together by weak bonds between complementary base pairs.

Adenine (A) always pairs with thymine (T) and guanine (G) always pairs with cytosine (C).

Each base pair is flat and can stack on top of each other, helping form the double helix structure of DNA.

DNA is made up of two strands that run in opposite directions, like a two-lane highway.

The sequence of bases in DNA holds the genetic information that determines an organism's traits.

The arrangement of bases in DNA can be easily stored and analyzed by computers using a simple binary code.

DNA is a stable molecule that can be accurately copied during cell division. This allows for the transmission of genetic information from one generation to the next.

The genetic code in DNA is copied into RNA allowing the production of proteins that control an organism's traits.

DNA can change over time through mutations, which are alterations in the sequence of bases. These changes can be beneficial, harmful, or neutral.

DNA wraps twice around a core of eight histone proteins, forming a bead-like structure called a nucleosome. This is the first level of DNA packaging.

Histone H1 acts like a binder, pulling nucleosomes together to form a more compact structure known as a chromatin fiber.

Scaffold proteins are involved in the higher-order packaging of chromatin fibers, further condensing the DNA into a chromosome. Think of it like a scaffolding structure holding the chromatin fibers together.

Euchromatin refers to less condensed regions of DNA that are actively transcribed, meaning genes in these regions are being expressed. Heterochromatin, on the other hand, is more condensed and contains DNA that is not actively transcribed.

DNA is a double helix, and its base sequence is read in a 5' to 3' direction. The complementary strand of DNA will have an opposite base sequence, going from 3' to 5'. Remember that adenine (A) pairs with thymine (T), and guanine (G) pairs with cytosine (C).

The central dogma describes the flow of genetic information from DNA to RNA to protein. DNA is transcribed into RNA, and RNA is translated into protein. This process underlies gene expression, the production of functional proteins from genetic instructions.

RNA and DNA are both nucleic acids, but they differ in their chemical composition and structure. RNA contains uracil (U) instead of thymine (T) in DNA. RNA is typically single-stranded, while DNA is double-stranded. RNA is also shorter than DNA.

DNA is a more stable molecule than RNA because it has a deoxyribose sugar, which lacks a hydroxyl group compared to ribose in RNA. This makes DNA less prone to degradation. DNA's double-stranded structure also provides additional stability.

Transcription proceeds in a 5' to 3' direction. This means that the RNA polymerase enzyme reads the DNA template strand from 3' to 5', but produces a complementary RNA strand in the 5' to 3' direction.

Eukaryotic RNA splicing is carried out by snRNPs, which are small nuclear ribonucleoproteins. These are composed of RNA and protein. Introns, non-coding sequences, are removed, and exons, coding sequences, are joined to produce a mature mRNA molecule.

Nuclear pore complexes are large channels that control the passage of molecules between the nucleus and cytoplasm. They act as selective gates, allowing only mature mRNA molecules to exit the nucleus for translation.

In the pulse-chase experiment, cells were exposed to radioactive uracil, a component of RNA. This allowed researchers to track RNA synthesis and movement within the cell over time. The results showed that RNA was synthesized in the nucleus and then moved to the cytoplasm, suggesting its role in protein synthesis.

RNA, a molecule similar to DNA but with a single strand and the base Uracil instead of Thymine, carries genetic instructions from the nucleus to the ribosomes for protein synthesis.

Ochoa and Kornberg were awarded the Nobel Prize in 1959 for discovering enzymes responsible for synthesizing RNA and DNA, respectively. These enzymes are crucial for replicating and transcribing genetic information.

The absence of a hydroxyl group at the 2' position of the sugar molecule in DNA makes DNA more stable than RNA. This stability is essential for storing genetic information over long periods.

The ribosomes are responsible for protein synthesis. They read the genetic instructions carried by mRNA and assemble amino acids into protein chains.

François Jacob, Jacques Monod, and André Lwoff received the Nobel Prize in Physiology or Medicine in 1965 for their groundbreaking work on gene regulation. Their research shed light on how gene expression is controlled in bacteria.

RNA acts as a messenger, carrying genetic instructions from DNA in the nucleus to the protein-making machinery in the cytoplasm. This process is crucial for gene expression.

Uracil (U) in RNA base-pairs with Adenine (A) similarly to Thymine (T) in DNA. This pairing is critical for the proper translation of genetic code during protein synthesis.

RNA is more reactive than DNA because the ribose sugar in RNA contains a hydroxyl group (OH) at the 2' carbon, making it more susceptible to chemical reactions.

DNA is primarily responsible for long-term storage of genetic information, while RNA is involved in the short-term processes of gene expression.

RNA typically exists as a single-stranded molecule, but it can fold into complex 3D structures by forming base pairs within its own sequence, creating regions of double-strandedness.

RNA molecules perform a wide variety of functions in cells, including carrying genetic information, acting as enzymes (ribozymes), and regulating gene expression.

Messenger RNA (mRNA) is a type of RNA that carries the genetic code from DNA to ribosomes, where protein synthesis takes place.

Transcription is the process by which RNA polymerase uses a DNA template to synthesize a complementary RNA molecule.

RNA polymerase is an enzyme responsible for synthesizing RNA molecules from a DNA template.

In eukaryotic cells, three different RNA polymerases carry out transcription. RNA polymerase I transcribes ribosomal RNA (rRNA), RNA polymerase II transcribes messenger RNA (mRNA), and RNA polymerase III transcribes transfer RNA (tRNA).

Ribosomal RNA (rRNA) is a type of RNA that forms part of the ribosomes, which are the protein synthesis machinery of cells.

Transfer RNA (tRNA) is a type of RNA that carries amino acids to ribosomes during protein synthesis.

Non-coding sequences within eukaryotic genes that are removed during RNA processing.

A complex machinery composed of snRNAs and proteins responsible for splicing out introns and joining exons in eukaryotic pre-mRNA.

The process by which a single pre-mRNA molecule can be spliced in different ways, leading to the production of multiple protein isoforms from the same gene.

A type of RNA-binding protein that recognizes and binds to mature mRNA molecules, marking them for export from the nucleus.

A large channel in the nuclear membrane that regulates the passage of molecules between the nucleus and cytoplasm, allowing only mature mRNA to exit.

RNA polymerase, the enzyme that makes RNA, uses a DNA strand as a template to build a complementary RNA molecule. One strand serves as a template, and the other has the same sequence as the RNA being made.

RNA production occurs in a 5' to 3' direction, meaning the RNA strand is assembled from the 5' end to the 3' end. The template DNA strand is read in the opposite direction, from 3' to 5'.

Eukaryotic cells have a nucleus, where DNA is kept, and a cytoplasm, where proteins are made. The mRNA is processed to make sure it's ready for translation.

A 5' cap is a modified guanine nucleotide added to the 5' end of the mRNA. This protects it from degradation and helps it bind to ribosomes, where protein synthesis occurs.

A poly-A tail, a chain of adenine nucleotides, is added to the 3' end. It helps with mRNA stability, increases its lifespan, and aids in translation initiation.

Introns are non-coding sequences within the mRNA transcript. They are removed during splicing, leaving only the exons, the coding regions, behind.

The sequence of bases in mRNA is translated into a sequence of amino acids, which form a chain, making the final protein. This translation occurs in the ribosomes.

Ribosomes are tiny cellular factories that read the mRNA code and use it to assemble amino acids into a protein chain. They're like protein builders.

Before mRNA can leave the nucleus, it undergoes a process called splicing. This involves removing introns, non-coding regions, and joining together exons, coding regions, to make a mature mRNA transcript ready for translation.

The genetic code is a set of rules that determines how the sequence of nucleotides in DNA or RNA is translated into a sequence of amino acids in a protein.

The genetic code is universal, meaning it is the same in all living organisms. It is non-overlapping, meaning each nucleotide is part of only one codon. It is degenerate, meaning that multiple codons can code for the same amino acid.

mRNA carries the genetic information from DNA to the ribosomes, tRNA carries amino acids to the ribosomes, and rRNA is a structural component of the ribosomes.

Translation is the process by which the genetic information encoded in mRNA is used to synthesize a protein.

The first stage of translation is initiation, where the ribosome binds to the mRNA and the first tRNA carrying the amino acid methionine binds to the start codon.

The second stage of translation is elongation, where the ribosome moves along the mRNA, adding amino acids to the growing polypeptide chain.

The final stage of translation is termination, where the ribosome encounters a stop codon and releases the completed polypeptide chain.

The genetic code was cracked through a series of experiments that used synthetic mRNA molecules to determine the codons that coded for each amino acid.

Three-nucleotide sequences in mRNA that code for specific amino acids.

The process by which the sequence of nucleotides in mRNA is translated into a sequence of amino acids in a protein.

The set of rules that determines how the sequence of nucleotides in DNA or RNA is translated into a sequence of amino acids in a protein.

Cellular structures responsible for protein synthesis. They read the genetic code in mRNA and assemble amino acids into protein chains.

A sequence of three nucleotides in DNA that codes for an amino acid.

A set of three nucleotides in tRNA that is complementary to a codon in mRNA.

The stage of translation where the ribosome binds to the mRNA and the first tRNA carrying the amino acid methionine binds to the start codon.

The stage of translation where the ribosome moves along the mRNA, adding amino acids to the growing polypeptide chain.

The genetic code is not overlapping, meaning a single base mutation affects only one amino acid. This is because changing a single base would change multiple amino acids if the code was overlapping.

Proflavin, a planar molecule, can intercalate between base pairs in DNA, causing either an insertion or deletion of a single base.

Frameshift mutations alter the reading frame of the genetic code, leading to a change in the amino acid sequence. This is because the code is read in groups of three bases, and adding or removing a base shifts this reading frame.

A double mutant, created by introducing two insertions (+ +) or two deletions (- -) in the same direction, disrupts the reading frame, resulting in a mutant phenotype.

Adding an insertion (+) and a deletion (-) in the same gene creates a pseudo-wild type, restoring the reading frame and resulting in a wild-type phenotype. This confirms the frameshift nature of insertions and deletions.

Crick's experiments with frameshift mutations in bacteriophage T4 demonstrated that the genetic code is not overlapping and is read in groups of three bases. This is because adding or removing a single base resulted in a frameshift mutation, affecting the entire sequence downstream of the mutation.

Wild-type bacteriophage plaques appear as normal-sized, circular areas of cleared bacteria on a petri dish, while rII mutant plaques are distinctive "large plaques" due to mutations in the rII gene.

Bacteriophage T4 infects Escherichia coli, a common bacterium.

Recombination in bacteriophage T4 allowed researchers to bring together different mutations, resulting in recombinants with different combinations of mutations.

The minimum code word size for an amino acid is three nucleotides because 20 amino acids need at least 64 possible combinations, which can be achieved with 3 nucleotides (4^3 = 64).

Ribosomes are complexes of protein and RNA that function in protein synthesis. They read the genetic code in mRNA, using it to assemble amino acids into polypeptide chains. Think of them as tiny cellular factories that build proteins.

rRNA, or ribosomal RNA, is a key component of ribosomes. It provides the structural framework for the ribosome and helps it bind to mRNA and guide the correct tRNA molecules during protein synthesis.

The three steps of translation are initiation, elongation, and termination. Initiation involves the assembly of the translation machinery, elongation extends the polypeptide chain by adding amino acids, and termination marks the end of protein synthesis.

The genetic code is translated by aminoacyl-tRNA synthetases and tRNAs. Each synthetase couples a specific amino acid to its corresponding tRNA.

tRNA molecules can tolerate a mismatch at the third position of the codon, known as wobble. This allows some tRNAs to recognize multiple codons.

tRNA is the key to deciphering the codons in mRNA. Each tRNA molecule carries a specific amino acid and recognizes a particular codon sequence, ensuring the correct amino acid is added to the polypeptide chain during translation.

The ribosomes read the mRNA sequence and use this information to assemble amino acids into a polypeptide chain. Imagine them as the protein-building factories of the cell.