Quiz 1 Flashcards
currently, there is much interest in studying the different “omes”. Which of the following “ome” is matched with its correct biomolecule?
A) transcriptome - proteins
B) metabolome - mRNA
C) proteome - proteins
D) genome - mRNA
C) proteome - proteins
NOTE: the first part of the name tells which biomolecule is being included in the collection. Proteins form the proteome, metabolomics involves the study of metabolites, RNA transcripts define the transcriptome, and the DNA of an organism makes up its genome.
DNA mutations can ultimately lead to diseases in humans. An example of a disease resulting from a somatic cell mutation would be
A) huntington’s disease
B) tay-sachs disease
C) lung cancer
D) breast cancer related to BRCA1 gene
C) lung cancer
NOTE: tay-sachs and huntington’s diseases are both inherited diseases resulting from germ-line cell mutations. inherited mutations in the BRCA1 gene are implicated in breast cancers and are also germ-line mutations. lung cancers commonly result from mutations that occur based on exposure to carcinogens and are thus somatic cell mutations.
fatty acids are important for cell membrane formation because they are
A) only hydrophilic
B) only hydrophobic
C) amphipathic
D) only polar
C) amphipathic
NOTE: fatty acids are amphipathic. they contain a polar group, which is hydrophilic, and a nonpolar hydrocarbon tail. having both properties allows fatty acids to form hydrophobic barriers that separate aqueous phases.
high-throughput DNA sequencing and bioinformatics have greatly facilitated our ability to study evolutionary history. which of the following is correctly defined?
A) steroid receptor gene and globin receptor gene sequences in human are highly conserved and are called orthologs
B) glucose-6-phosphate gene sequences from a human and a chimpanzee are highly conserved and are called paralogs
C) a human receptor gene and a mosquito receptor gene are highly conserved and are called paralogs
D) glucose-6-phosphate gene sequences from a human and a chimpanzee are highly conserved and are called orthologs
D) glucose-6-phosphate gene sequences from a human and a chimpanzee are highly conserved and are called orthologs
NOTE: orthologs are genes that are highly conserved between different species. paralogs are genes that result from gene duplications within an organism, but where the duplicated gene accumulates, mutates, and evolves a new, but related, function
in addition to being a part of a nucleotide found in nucleic acids, which nucleotide base is also found in the coenzymes NAD+ and FAD?
A) guanine
B) cytosine
C) adenine
D) thymine
C) adenine
NOTE: coenzymes NAD+ and FAD are dinuleotides. the “A” in each stands for adenine. the nucleotide bases are typically abbreviated by single letters, i.e., A= adenine, G=guanine, C=cytosine, and T=thymine
organisms on earth are considered ______ life forms.
A) carbon
B) oxygen
C) nitrogen
D) hydrogen
A) carbon
NOTE: ignoring the contributions to hydrogen and oxygen amounts from water, carbon is the most abundant element in the human body. carbon’s unique ability to form four covalent bonds is the basis for forming a variety of organic molecules
proteins are made up of _____ linked by _____ bonds.
A) amino acids; peptide
B) fatty acids; ester
C) nucleotides; phosphodiester
D) sugars; glycosidic
A) amino acids; peptide
NOTE: amino acids, nucleotides, and sugars are each polymerized to form different polymeric structures (proteins, nucleic acids, and polysaccharides, respectively). the linkage between amino acids is called a peptide bond.
the RNA world model proposes that RNA predates DNA and proteins. which property of RNA is NOT a part of this model?
A) RNA is capable of catalysis
B) RNA contains uracil rather than thymine
C) RNA directs the synthesis of proteins
D) RNA is unstable due to its ability to self-cyclize and cleave its sugar-phophate backbone
B) RNA contains uracil rather than thymine
NOTE: RNA is capable of storing and transferring genetic information (like DNA) and can catalyze reactions (like protein). The chemical instability of RNA led to more stable (DNA) and more chemically functional (protein) biomolecules to take over genetic storage and catalytic function in modern life. The presence of uracil in RNA with thymine in DNA is important for maintaining the integrity of the genome, but is not a part of the RNA world model.
the binding of a ligand to a receptor is important for allowing external signals to affect intracellular processes. which property of receptor proteins is key for this signaling to occur?
A) non-rigid structure that allows for conformational changes when a ligand binds
B) non-specific interactions with intracellular molecules
C) non-specific interactions with extracellular molecules
D) non-reversible binding to ligand
A) non-rigid structure that allows for conformational changes when a ligand binds
NOTE: Flexibility and the ability to undergo conformational changes allow receptor proteins to bind an external ligand and cause an internal event. Receptor proteins have specific interactions with both extracellular and intracellular molecules, which allows for specific signaling to occur. Binding to a ligand needs to be reversible so a signal is turned off when extracellular concentrations change.
the endosymbiotic theory proposes that eukaryotic cells arose as a result of large cells engulfing smaller, aerobic bacteria. the organelle that provides evidence for this theory is
A) mitochondria
B) lysosomes
C)nucleus
D) golgi apparatus
A) mitochondria
NOTE: Mitochondria have their own DNA genome and are capable of producing proteins. Genetic analysis of mitochondria DNA and bacterial DNA show similarities.
The figure below depicts the flow of information as described by the central dogma of molecular biology. Which of the following are the correct terms for steps 1–4?
A) 1. reverse transcription 2. replication 3. translation 4. transcription
B) 1. replication 2. reverse transcription 3. transcription 4. translation
C) 1. replication 2. transcription 3. reverse transcription 4. translation
D) 1. replication 2. transcription 3. translation 4. reverse transcription
C) 1. replication 2. transcription 3. reverse transcription 4. translation
NOTE: The process of copying DNA to make more DNA is called replication. The information in DNA is transcribed into RNA, a related biomolecule, and so the opposite process is called reverse transcription. The information in RNA is then translated into a different biomolecule, protein.
The figure below shows a generic metabolic pathway. The direction of which reaction step is going to be determined by Le Chatelier’s principle?
A) 3
B) 4
C) 1
D) 2
D) 2
NOTE: The reaction between B and C is a reversible reaction, as indicated by the double arrows. The direction of this reaction is going to be determined by the intracellular concentrations of B and C and the equilibrium between the two (Le Chatelier’s principle). The reaction of A to B requires ATP, indicating energy is needed to drive the reaction and making it irreversible. The other reactions have single arrows, indicating a favored direction and little reversibility.
The figure below shows two different transcription factors. Which of the following statements describes these two proteins?
A) protein structure is not determine by its amino acid sequence
B) proteins with a similar structure can have similar functions
C) proteins with different structures can have similar functions
D) proteins with a similar structure can have different functions
C) proteins with different structures can have similar functions
NOTE: Protein structure is determined by the amino acid sequence. For highly related genes it can be possible to predict structure and function, but that is not always the case. Some proteins can have a similar structure, but different functions and vice versa.
Three examples of polysaccharides are shown in the figure below. What is the monosaccharide and glycosidic bond in cellulose 2?
A) glucose, B(1-4)
B) N-acetylglucosamine, B(1-4)
C) glucose, a(1-4)
D) N-acetylglucosamine, a(1-4)
A) glucose, B(1-4)
NOTE: 1 and 2 are both polysaccharides of glucose, but differ in the glycosidic bond. 1 is the α(1 → 4) linkage and 2 is the β(1 → 4) linkage. 3 also has the β(1 → 4) linkage, but the monosaccharide is N-acetylglucosamine.
Which of the following allows for the transfer of information for DNA replication, RNA transcription, and RNA translation?
A) formation of the double helix
B) 5’ to 3’ directionality of a nucleic acid strand
C) hydrogen bonding between specific nucleobases to form base pairs
D) base stacking interactions
C) hydrogen bonding between specific nucleobases to from base pairs
NOTE: Base stacking and the directionality of each nucleic acid strand contributes to the formation of a stable double helix. The transfer of information in nucleic acids comes from the formation of stable base pairs via hydrogen bonding. A pairs with T/U and G pairs with C. Having the information in one strand allows for replication of the second strand in DNA and the transfer of information into RNA and ultimately protein.
