Flashcards in this deck (117)

• What are proteins primarily responsible for in cells?

  Active participants in cell structure and function.
  biology proteins
• What are genes that encode polypeptides called?

  Protein-encoding genes or structural genes.
  genetics genes
• What is transcribed into messenger RNA (mRNA)?

  Protein-encoding genes.
  molecular_biology mrna
• What is the main function of genetic material?

  To encode the production of cellular proteins.
  genetics function
• Why must cellular proteins be produced correctly?

  In the correct cell, at the proper time, and in suitable amounts.
  biology protein_synthesis
• Who was the first to propose a link between genes and protein production?

  Archibald Garrod
  history genetics
• What condition did Garrod study that affected metabolism?

  Alkaptonuria
  medicine metabolism
• What is a key symptom of alkaptonuria?

  • Black urine
  • Bluish black discoloration of cartilage and skin
  medicine symptoms
• What accumulates in the bodies of patients with alkaptonuria?

  Homogentisic acid (alkapton)
  biochemistry metabolism
• When did Garrod make his contributions to genetics?

  At the beginning of the 20th century
  history genetics
• What relationship did Garrod propose regarding genes?

  A connection between genes and protein production
  genetics protein
• What enzyme is missing in alkaptonuria?

  Homogentisic acid oxidase
  genetics enzymes
• What inheritance pattern does alkaptonuria follow?

  Recessive pattern of inheritance
  genetics inheritance
• What did Garrod propose about enzyme inheritance?

  A relationship exists between the trait and a defective enzyme.
  genetics enzyme
• How did Garrod describe alkaptonuria?

  As an inborn error of metabolism.
  metabolism genetics
• What is the primary amino acid involved in the metabolic pathway discussed?

  Phenylalanine
  biochemistry metabolism
• What enzyme converts phenylalanine into tyrosine?

  Phenylalanine hydroxylase
  biochemistry enzymes
• Identify a disease caused by mutations in the phenylalanine metabolism pathway.

  Phenylketonuria
  genetics diseases
• What does a mutation in the tyrosine aminotransferase enzyme cause?

  Tyrosinosis
  genetics diseases
• What is one result of defects in the homogentisic acid oxidase enzyme?

  Alkaptonuria
  genetics diseases
• What type of diseases arise from missing or defective enzymes?

  Metabolic diseases
  biochemistry diseases
• What are the key components of the metabolic pathway of phenylalanine?

  • Phenylalanine
  • Tyrosine
  • p-Hydroxyphenylpyruvic acid
  • Homogentisic acid
  • Maleylacetoacetic acid
  biochemistry metabolism
• What do mutations in the metabolic pathway of phenylalanine affect?

  Enzymatic conversions
  genetics biochemistry
• Who conducted experiments on the relationship between genes and enzymes in the 1940s?

  George Beadle and Edward Tatum
  history genetics
• What was the genetic model used by Beadle and Tatum for their studies?

  Neurospora crassa (bread mold)
  biology experiments
• What key question did Beadle and Tatum investigate?

  Is it one gene–one enzyme or one gene–many enzymes?
  genetics theories
• What aspect of Neurospora crassa did Beadle and Tatum analyze?

  Simple nutritional requirements
  biology nutrition
• What theory did Beadle and Tatum contribute to in genetics?

  The one gene–one enzyme hypothesis
  genetics theories
• What was the focus of Beadle and Tatum's experiments?

  Analyzed enzyme pathways for synthesis of vitamins and amino acids.
  genetics experiments
• How many strains did Beadle and Tatum analyze in their research?

  More than 2,000 strains that had been irradiated to produce mutations.
  genetics research
• What hypothesis did Beadle and Tatum propose?

  One gene–one enzyme theory.
  genetics theories
• Which scientist's contributions are related to metabolic pathways?

  Garrod's contributions.
  genetics history
• What overarching concept relates genes to protein synthesis?

  Protein encoding genes.
  genetics protein_synthesis
• What type of media were Neurospora strains tested on?

  • Minimal plates
  • Plates supplemented with:
  • O-acetylhomoserine
  • Cystathionine
  • Homocysteine
  • Methionine
  biology media
• What was observed on the plates showing the growth of Neurospora strains?

  • No growth in some conditions
  • Varying degrees of growth for wild-type and mutant strains
  biology observations
• What is the key purpose of using supplemented growth media?

  To assess the nutritional requirements of different Neurospora strains.
  biology nutrition
• What does the term 'wild type' refer to in Neurospora?

  The standard strain used for comparison with mutant strains.
  genetics wild_type
• What could the absence of growth in mutant strains indicate?

  A potential enzyme deficiency in the biosynthetic pathway for the given nutrients.
  biology mutants
• Name one nutrient that was used in supplemented media.

  • Methionine
  biology nutrients
• What is the first step in the methionine biosynthesis pathway?

  Conversion of Homoserine to O-acetylhomoserine
  metabolism biosynthesis
• Which enzyme converts O-acetylhomoserine to Cystathionine?

  Enzyme 1
  metabolism enzymes
• In the methionine biosynthesis pathway, what is formed after Cystathionine?

  Homocysteine
  metabolism biosynthesis
• What is the final product of the methionine biosynthesis pathway?

  Methionine
  metabolism biosynthesis
• Identify the enzyme responsible for converting Homocysteine to Methionine.

  Enzyme 4
  metabolism enzymes
• Which strains are missing specific enzymes in the pathway?

  Strains 1, 2, 3, and 4 each lack different enzymes.
  genetics research
• What was synthesized by cellular enzymes in normal strains?

  Methionine
  genetics enzymes
• What caused the inability to synthesize methionine in mutant strains?

  Genetic defect in one gene
  genetics mutations
• What does the one gene–one enzyme hypothesis state?

  A single gene controls the synthesis of a single enzyme.
  genetics hypotheses
• Who proposed the one gene–one enzyme hypothesis?

  Beadle and Tatum
  history genetics
• What is a consequence of a defect in one gene?

  Prevention of synthesis of a protein required for methionine production.
  genetics proteins
• What is a more precise term for what a structural gene encodes?

  A polypeptide
  genetics proteins
• What does the term 'polypeptide' refer to?

  The structure of a protein
  definitions proteins
• What does the term 'protein' refer to?

  The function of a polypeptide
  definitions proteins
• Are enzymes the only category of proteins?

  No, enzymes are only one category of proteins
  biology enzymes
• Can some proteins be composed of more than one polypeptide?

  Yes, some proteins are composed of multiple polypeptides
  biology proteins
• Which types of molecules can some genes encode apart from polypeptides?

  • Functional RNA molecules
  • tRNA
  • rRNA
  genetics molecules
• How can one gene lead to multiple polypeptides?

  Through alternative splicing.
  genetics splicing
• What does the One Gene-One Enzyme theory imply?

  Each gene encodes a specific enzyme (now outdated).
  genetics theory
• What is the process of translation in genetics?

  The interpretation of mRNA nucleotide language into amino acid language of proteins.
  genetics translation
• What does the genetic code rely on?

  It relies on codons, which are groups of three nucleotides in mRNA.
  genetics genetic_code
• What language does mRNA get translated into during protein synthesis?

  The amino acid language of proteins.
  genetics protein_synthesis
• Identify a key component of the genetic code.

  Codons.
  genetics genetic_code
• What does the genetic code specify?

  The relationship between mRNA codons and amino acids.
  genetics molecular_biology
• Identify the first step in protein synthesis.

  Transcription of DNA into mRNA.
  genetics protein_synthesis
• What is the significance of the one gene–one enzyme theory?

  It proposes that a single gene encodes a specific enzyme.
  genetics theory
• Which scientist is associated with the one gene–one enzyme theory?

  George Beadle and Edward Tatum.
  history science
• Define the role of codons in the genetic code.

  Codons are triplets of nucleotides that correspond to specific amino acids.
  genetics molecular_biology
• List the four nucleotides involved in mRNA.

  • Adenine (A)
  • Uracil (U)
  • Cytosine (C)
  • Guanine (G)
  genetics nucleotides
• What is the start codon for protein synthesis?

  AUG (Methionine).
  genetics start_codon
• How many stop codons are there in the genetic code?

  Three stop codons.
  genetics stop_codons
• Explain Garrod's contribution to understanding genetics.

  He linked genes to enzymatic actions in metabolism.
  history genetics
• What's the relationship between genes and metabolic pathways?

  Genes code for enzymes that control metabolic pathways.
  genetics metabolism
• Show how the genetic code table relates mRNA to amino acids.

  Each mRNA codon corresponds to a specific amino acid or stop signal.
  genetics molecular_biology
• What is the start codon in the genetic code?

  AUG specifies methionine and defines the reading frame for all subsequent codons.
  genetics codons
• What are the stop codons in the genetic code?

  UAA, UAG, and UGA are the termination codons.
  genetics codons
• What does it mean that the genetic code is degenerate?

  More than one codon can specify the same amino acid, like GGU, GGC, GGA, and GGG for glycine.
  genetics degeneracy
• In the genetic code, which base is often variable?

  The third base in the codon is usually the variable base.
  genetics codons
• How universal is the genetic code?

  The genetic code is nearly universal, with only a few rare exceptions.
  genetics universality
• What relationship does the one gene–one enzyme theory suggest?

  Each gene encodes one enzyme responsible for a specific metabolic pathway.
  genetics theories
• What contribution did Garrod make to genetics?

  Garrod proposed that genes influence metabolic pathways linked to inherited diseases.
  genetics history
• Who developed the one gene–one enzyme theory?

  Beadle and Tatum proposed this theory based on their experiments with mold.
  genetics theories
• What are selenocysteine and pyrrolysine often referred to as?

  • 21st amino acid
  • 22nd amino acid
  genetics amino_acids
• In what type of enzymes are selenocysteine and pyrrolysine commonly found?

  In specialty enzymes.
  biochemistry enzymes
• Which codon encodes for selenocysteine?

  UGA
  genetics codons
• Which codon is responsible for encoding pyrrolysine?

  UAG
  genetics codons
• How are selenocysteine and pyrrolysine attached to the ribosome?

  By tRNAs that carry them.
  genetics protein_synthesis
• What does mRNA need in addition to codons to incorporate selenocysteine and pyrrolysine?

  Codon and downstream sequences.
  genetics mrna
• What does the codon AUA code for?

  Methionine in yeast and vertebrate mitochondria.
  genetics codons
• What does the codon UGA typically code for?

  Isoleucine in standard genetic code.
  genetics codons
• In what context does UGA code for Tryptophan?

  In vertebrate mitochondria.
  genetics exceptions
• What do the codons CUU, CUC, CUA, CUG normally code for?

  Stop codon in standard genetic code.
  genetics codons
• In yeast mitochondria, what do the CUU, CUC, CUA, CUG codons code for instead?

  Threonine.
  genetics exceptions
• What do the codons AGA, AGG usually represent?

  Leucine in standard genetic code.
  genetics codons
• In which context do AGA, AGG act as stop codons?

  In ciliated protozoa and yeast and vertebrate mitochondria.
  genetics exceptions
• What do the codons UAA, UAG code for in standard genetic code?

  Arginine.
  genetics codons
• In ciliated protozoa, what do UAA, UAG codons code for instead?

  Glutamine.
  genetics exceptions
• What does UGA signify in certain bacteria, archaea, and eukaryotes?

  Selenocysteine.
  genetics exceptions
• What does the codon UAG represent in methane-producing archaea?

  Pyrrolysine.
  genetics exceptions
• What is the initial step in gene expression?

  Transcription of DNA into mRNA.
  gene_expression transcription
• Identify the final product of gene expression.

  Polypeptide chain.
  gene_expression translation
• What is the role of tRNA in translation?

  Carries amino acids to the ribosome.
  translation trna
• What are the components that make up mRNA?

  • 5'-untranslated region
  • Start codon
  • Codons
  • Stop codon
  • 3'-untranslated region
  mrna gene_expression
• List the phases of gene expression.

  • Transcription
  • Translation
  gene_expression phases
• What does the one gene–one enzyme theory propose?

  Each gene encodes a specific enzyme.
  genetics theory
• What did Beadle and Tatum's hypothesis suggest?

  Genes control metabolic pathways.
  genetics hypothesis
• Explain the term genetic code.

  Set of rules by which mRNA sequences are translated into proteins.
  genetics genetic_code
• What is represented in the diagram related to gene expression?

  Flow from DNA to mRNA to polypeptide.
  gene_expression diagram
• What is the directionality of polypeptide synthesis?

  It parallels the 5' to 3' orientation of mRNA.
  biology synthesis
• What type of bond forms during polypeptide elongation?

  A peptide bond forms between amino acids.
  biology chemistry
• What is the first amino acid in a polypeptide chain known as?

  The N-terminal or amino terminal end.
  biology structure
• What distinguishes the last amino acid in a polypeptide chain?

  It has an exposed carboxyl group, known as C-terminal.
  biology structure
• What does a polypeptide chain have?

  Directionality
  biochemistry polypeptides
• What is produced during the formation of a peptide bond?

  Water
  biochemistry peptide_bonds
• What are the two ends of a polypeptide called?

  • Amino-terminus
  • Carboxyl-terminus
  biochemistry polypeptides
• What amino acid starts most polypeptide chains?

  Methionine
  biochemistry amino_acids
• What is the relationship between mRNA and polypeptide directionality?

  They both share the same directionality.
  biochemistry mrna
• Name the codons associated with the amino acids noted in polypeptide synthesis.

  • AUG
  • AGC
  • GUU
  • UAC
  • UGC
  biochemistry genetics