All flashcards
Flashcard 1: What is the most direct reason that changing amino acids can change a trait?
Answer: Amino acid changes can change protein shape and therefore function. Shape determines function; altered shape means altered activity.
Flashcard 2: Which level of protein structure is most directly determined by the gene sequence?
Answer: Primary structure (the amino acid sequence). DNA directly codes for amino acid order, not folding patterns.
Flashcard 3: What is an enzyme, and how can enzyme changes affect traits?
Answer: A protein catalyst; changes can alter reaction rates and outcomes. Enzymes speed reactions; altered enzymes change metabolic outcomes.
Flashcard 4: What is an active site, and why is it important for connecting protein changes to traits?
Answer: The binding/catalytic region; changes can reduce or stop enzyme action. Where substrates bind; shape changes prevent proper binding.
Flashcard 5: What is a trait in biology, in the context of proteins affecting organisms?
Answer: An observable characteristic produced by protein function and environment. Proteins create physical features we can see or measure.
Flashcard 6: What is protein function, in the context of connecting genes to traits?
Answer: A protein’s job based on its shape, binding, and activity in cells. Shape determines what molecules it can bind and reactions it can perform.
Flashcard 7: What is the difference between loss-of-function and gain-of-function protein changes?
Answer: Loss reduces activity; gain creates new or increased activity. Loss removes normal function; gain adds abnormal function.
Flashcard 8: What is gene expression, and how can it change traits without changing DNA sequence?
Answer: How much protein is made; altered levels can change traits. More/less protein production changes trait without DNA mutation.
Flashcard 9: Identify what happens to a trait if a gene is not expressed in a tissue where its protein is needed.
Answer: The protein is absent there, so the related trait is altered. No expression means no protein to perform its function.
Flashcard 10: What is the role of structural proteins, and how can changes in them affect traits?
Answer: They support cells/tissues; changes can alter strength or shape traits. Collagen/keratin changes affect tissue properties directly.
Flashcard 11: What is a mutation, in the context of protein function and traits?
Answer: A change in DNA that can change a protein and thus a trait. DNA changes alter protein sequence, changing its function.
Flashcard 12: What is a missense mutation, and what is its typical effect on a protein?
Answer: A base change causing a different amino acid in the protein. One codon changes to another, substituting one amino acid.
Flashcard 13: What is a nonsense mutation, and what is its typical effect on a protein?
Answer: A base change creating a stop codon, producing a shorter protein. Early termination often destroys protein function completely.
Flashcard 14: What is a frameshift mutation, and why does it often strongly affect traits?
Answer: An insertion/deletion shifts reading frame, changing many amino acids. Reading frame shift scrambles all downstream codons.
Flashcard 15: Identify the most likely protein-level result of a mutation that deletes one nucleotide in a coding region.
Answer: Frameshift causing widespread amino acid changes after the deletion. Deletion shifts triplet reading pattern throughout remaining gene.
Flashcard 16: Identify the most likely trait result when a receptor protein can no longer bind its signal molecule.
Answer: Cells fail to respond to the signal, changing the organism’s trait. No binding means no signal transduction or cellular response.
Flashcard 17: Identify the most likely trait effect if a mutation reduces an enzyme’s activity in a pigment pathway.
Answer: Reduced pigment production, causing a color change trait. Less enzyme means less product, affecting visible coloration.
Flashcard 18: What is the relationship between a gene and a protein?
Answer: A gene contains DNA instructions for making a specific protein. DNA in genes codes for amino acid sequences that fold into proteins.
Flashcard 19: Which option best describes why two different alleles can cause different traits?
Answer: They can produce proteins with different functions or amounts. Different DNA sequences create proteins with varied activities.
Flashcard 20: Identify the most likely trait outcome if an enzyme works faster than normal in a pathway.
Answer: More product is made, increasing the trait linked to that product. Faster enzymes produce more product per unit time.
Flashcard 21: Which option best predicts the trait effect if a structural protein is weaker than normal?
Answer: Body structures become weaker or less stable, changing the trait. Structural proteins provide physical support and shape to cells/tissues.
Flashcard 22: Which option best predicts the trait effect if a receptor protein cannot bind its signal molecule?
Answer: Cell signaling is disrupted, altering the related trait. Receptors must bind signals to trigger cellular responses.
Flashcard 23: Which option best describes how a nonfunctional pigment-making enzyme affects appearance?
Answer: Less or no pigment is made, changing coloration. Enzyme failure prevents pigment synthesis, altering appearance.
Flashcard 24: Identify the direct link in this chain: DNA change → protein change → what final outcome?
Answer: A change in an organism trait (phenotype). Altered proteins lead to changed observable characteristics.
Flashcard 25: What is the most likely effect of a frameshift mutation on a protein’s function?
Answer: Major change in amino acid sequence; often loss of function. Shifts reading frame, changing all downstream amino acids.
Flashcard 26: Which type of mutation changes one amino acid in a protein: silent, missense, or nonsense?
Answer: Missense mutation. Substitutes one amino acid for another in the protein chain.
Flashcard 27: What is the main reason a changed amino acid sequence can change a trait?
Answer: It can change protein shape and therefore protein function. Protein shape determines how it interacts and functions in cells.
Flashcard 28: Identify the level of protein structure most directly tied to function: shape or color?
Answer: Shape. 3D shape determines how proteins bind substrates and perform functions.
Flashcard 29: What is a trait in an organism, in terms of proteins?
Answer: An observable characteristic produced by protein activity in cells. Proteins create physical features we can see or measure.
Flashcard 30: A mutation increases the amount of a growth-factor protein made. What is the most likely trait-level result?
Answer: Increased growth signaling, potentially causing larger or faster growth. More growth factor stimulates more cell division.