Biochemistry Chapter 8 Quiz

TCAG

<p>Hydrogen bond</p> Signup and view all the answers

<p>A covalent bond that forms the backbone of DNA and RNA molecules</p> Signup and view all the answers

<p>DNA 1</p> Signup and view all the answers

<p>The sequence of bases</p> Signup and view all the answers

<p>Hydrogen bonding, Base stacking, Hydrophobic interactions</p> Signup and view all the answers

<p>Cytosine</p> Signup and view all the answers

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

<p>They modeled the structure of DNA based on the limited data available</p> Signup and view all the answers

<p>DNA is more resistant against enzymes that break down nucleic acids. (B)</p> Signup and view all the answers

<p>Hairpin Structure = A structure that may be formed from a single DNA strand with the sequence -ATATG.....CATAT- G tetraplex = Four-stranded, right-handed helix formed by a DNA segment containing a high proportion of guanine residues Cruciform structure = A structure formed when interstrand hydrogen bonds break and intrastrand hydrogen bonds form Triplex DNA = A polynucleotide strand that forms Hoogsteen pairs with functional groups in the major groove of a homopurine-homopyrimidine duplex</p> Signup and view all the answers

<p>snRNA; involved in the splicing process when mRNA is formed</p> Signup and view all the answers

<p>rRNA; Combines with proteins to form ribosomes</p> Signup and view all the answers

<p>tRNA; Brings amino acids to sites of mRNA during protein synthesis</p> Signup and view all the answers

<p>siRNA; Eliminates the expression of an undesirable gene</p> Signup and view all the answers

<p>mRNA; Carries genetic information to ribosomes for protein synthesis</p> Signup and view all the answers

<p>miRNA; Inhibits the translation of mRNA into protein</p> Signup and view all the answers

<p>Cytosine (A), Adenine (D)</p> Signup and view all the answers

<p>Nucleic acids are polymers of nucleotides used for: Storage of genetic information (DNA), Transmission of genetic information (mRNA), Processing of genetic information (ribozymes), Protein synthesis (tRNA and rRNA)</p> Signup and view all the answers

<p>Nucleotides are also used in the monomer form for cellular functions: Energy for metabolism (ATP), Enzyme cofactors (NAD+), Signal transduction (cAMP)</p> Signup and view all the answers

<p>Nitrogenous base, Pentose, Phosphate</p> Signup and view all the answers

<p>Nitrogenous base, Pentose</p> Signup and view all the answers

<p>A molecule in the backbone of DNA and RNA that links adjoining bases together; Negatively charged at neutral pH; Typically attached to 5' position</p> Signup and view all the answers

<p>Derivatives of pyrimidine or purine; Nitrogen-containing heteroaromatic molecules; Absorb UV light around 250-270 nm</p> Signup and view all the answers

<p>Modification is done after DNA synthesis; Common examples include 5-methylcytosine and N6-methyladenosine</p> Signup and view all the answers

<p>Inosine is sometimes found in the 'wobble position' of the anticodon in tRNA; Provides richer genetic code</p> Signup and view all the answers

<p>Pseudouridine is found widely in tRNA and rRNA; May stabilize the structure of tRNA</p> Signup and view all the answers

<p>Structural isomers that differ in the location of protons</p> Signup and view all the answers

<p>Ketones</p> Signup and view all the answers

<p>In some heterocycles; Forms a predominance at neutral pH</p> Signup and view all the answers

<p>Polymers of nucleic acids</p> Signup and view all the answers

<p>Via phosphodiester linkages</p> Signup and view all the answers

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

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

<p>No branching or cross-links</p> Signup and view all the answers

<p>RNA is unstable under alkaline conditions; RNase enzymes are abundant around us</p> Signup and view all the answers

<p>Two bases can hydrogen bond to form a base pair; Watson and Crick base pairs predominate in double-stranded DNA</p> Signup and view all the answers

<p>Strand separation occurs first; Each strand serves as a template for the synthesis of a new strand</p> Signup and view all the answers

<p>In nucleotides, the pentose ring is attached to the nitrogenous base via an N-glycosidic bond</p> Signup and view all the answers

<p>Relatively free rotation can occur; The bond is found in both syn and anti configurations</p> Signup and view all the answers

<p>Covalent bonds and genetic code remain intact; Hydrogen bonds are broken; Base stacking is lost</p> Signup and view all the answers

<p>The midpoint of melting (Tm) depends on base composition; High CG increases Tm</p> Signup and view all the answers

<p>Detection of a specific DNA molecule in complex mixtures; Amplification of specific DNA;</p> Signup and view all the answers

<p>Very slow reactions; Net effect is significant: 100 C --&gt; U events/day in a mammalian cell</p> Signup and view all the answers

<p>N-glycosidic bond is hydrolyzed; Significant for purines: 10,000 purines lost/day in a mammalian cell</p> Signup and view all the answers

<p>Hydroxylation of guanine; Mitochondrial DNA is most susceptible</p> Signup and view all the answers

<p>Methylation of guanine</p> Signup and view all the answers

<p>UV light induces dimerization of pyrimidines; Ionizing radiation causes ring opening and strand breaking</p> Signup and view all the answers

A nucleoside is a building block of nucleic acids, consisting of a nitrogenous base (adenine, guanine, cytosine, thymine, or uracil) attached to a pentose sugar (ribose or deoxyribose).

A nucleotide is a building block of nucleic acids, composed of a nitrogenous base, a pentose sugar, and a phosphate group.

Complementary base pairing in DNA involves the specific pairing of adenine (A) with thymine (T) and cytosine (C) with guanine (G) through hydrogen bonds. The complementary base pairing ensures accurate DNA replication and transcription.

Deoxyribonucleic acid (DNA) is a double-stranded, helical molecule that carries genetic information in the form of nucleotide sequences. It is typically found in the nucleus of eukaryotic cells.

Ribonucleic acid (RNA) is a single-stranded nucleic acid that plays a crucial role in protein synthesis. It is primarily found in the cytoplasm of cells.

The hydrogen bond is a weak chemical bond that plays a vital role in stabilizing the structure of DNA by holding together the complementary base pairs.

A phosphodiester bond is a covalent bond that links nucleotides together in a polynucleotide chain, forming the sugar-phosphate backbone of DNA and RNA.

Base stacking refers to the interaction between adjacent bases in a DNA helix, where the hydrophobic interactions between these bases contribute to the overall stability of the helix.

DNA denaturation (also called DNA melting) is the process of separating the two strands of a DNA double helix by breaking the hydrogen bonds between the complementary base pairs.

The melting temperature (Tm) of DNA is the temperature at which half of the DNA molecules in a solution have denatured. It is influenced by factors such as the length of the DNA sequence and the number of G-C base pairs.

Hairpin loops are secondary structures in DNA or RNA where a single strand folds back on itself, forming a loop structure stabilized by hydrogen bonds within the same strand.

G-quadruplexes are four-stranded DNA structures formed by guanine-rich sequences, where guanine bases interact through Hoogsteen base pairing.

Cruciform structures are DNA conformation formed by a palindromic sequence where the same sequence exists on two different strands, creating a cross-shaped structure.

Triplex DNA is a three-stranded structure in which a third strand interacts with a Watson-Crick double helix via Hoogsteen base pairing.

Methylation is a common epigenetic modification where a methyl group is added to a DNA base, typically cytosine or adenine. It can influence gene expression and is involved in various cellular processes.

Messenger RNA (mRNA) is a type of RNA that carries genetic information from DNA to ribosomes, where proteins are synthesized.

Transfer RNA (tRNA) is a type of RNA that delivers amino acids to ribosomes during protein synthesis, matching them to the mRNA codons.

Ribosomal RNA (rRNA) is a type of RNA that is a key component of ribosomes, the protein synthesis machinery.

Inosine is a modified nucleoside found in tRNA that can pair with adenine, cytosine, or uracil, increasing the flexibility of the genetic code.

Pseudouridine is another modified nucleoside found in tRNA and rRNA that contributes to RNA stability and structure.

Tautomerism is a phenomenon where a molecule can exist in two or more forms that differ in the location of a proton.

Prototropic tautomers are structural isomers that have different proton locations.

Keto-enol tautomerism is a type of tautomerism common in nucleotide bases, where a ketone group is interconverted with an enol group by moving a proton.

Lactam-lactim tautomerism involves the interconversion of a lactam (cyclic amide) and a lactim (cyclic imide) by shifting a proton.

A polynucleotide chain is a sequence of nucleotides linked together by phosphodiester bonds, forming the basis of DNA and RNA.

Deamination is a type of DNA damage where an amine group is removed from a base, typically adenine or cytosine, leading to mutations.

Depurination is a type of DNA damage where a purine base (adenine or guanine) is removed from the DNA backbone, leaving an apurinic site.

Alkylation is a type of DNA damage where an alkyl group is added to a DNA base, typically guanine, leading to mutations and potential cancer development.

Oxidative damage to DNA involves the modification of DNA bases by reactive oxygen species (ROS), leading to mutations and aging.

Antisense therapy utilizes synthetic single-stranded oligonucleotides (short sequences of DNA or RNA) that bind to specific mRNA sequences, blocking protein synthesis.

Fluorescent DNA chips utilize hybridization methods to detect specific sequences in DNA or RNA samples, allowing for the analysis of gene expression or the presence of genetic variations.