DNA Fundamentals
What is the structure of DNA and what are its components?
Double helix composed of nucleotides: sugar, phosphate, and nitrogenous base (A, T, C, G).
What is a gene?
A segment of DNA that codes for a specific protein.
What are proteins responsible for in cells?
Carrying out essential functions like enzymes, structural support, transport, and signaling.
Define mutation.
A change in the DNA sequence.
How does DNA ultimately influence an organism’s traits?
By coding for proteins that carry out cellular and systemic functions.
How do base-pairing rules work in DNA?
A pairs with T, and C pairs with G through hydrogen bonds.
How does transcription produce RNA from DNA?
RNA polymerase reads the DNA template to synthesize messenger RNA (mRNA).
Give two examples of specialized proteins and their roles.
Hemoglobin (transports oxygen), actin (cell structure), insulin (regulates blood sugar).
How can mutations affect protein structure?
They can change the amino acid sequence, potentially altering the protein’s shape and function.
What role do specialized cells play in expressing proteins?
They produce specific proteins needed for their particular function in a tissue or organ.
Which part of the DNA molecule carries the genetic code for proteins?
The sequence of nitrogenous bases.
What happens during translation?
Ribosomes read mRNA to assemble amino acids into a protein chain.
How do proteins interact with systems of specialized cells?
They enable cells to perform specific functions within tissues and organs.
What is a frameshift mutation?
Insertion or deletion of nucleotides that shifts the reading frame, affecting all downstream codons.
Give an example of a system in the body and a protein essential to its function.
Circulatory system: hemoglobin; digestive system: enzymes like amylase; immune system: antibodies.
Why is complementary base pairing important for DNA replication?
It ensures accurate copying of genetic information during cell division.
How do codons in mRNA determine amino acid sequence?
Each three-nucleotide codon codes for a specific amino acid.
Why are protein shapes important for their function?
Shape determines how proteins interact with other molecules; misfolded proteins often malfunction.
Why are some mutations silent?
Because they do not change the amino acid sequence due to the redundancy of the genetic code.
Why is DNA-protein interaction essential for homeostasis?
Proteins execute functions that maintain stable internal conditions and respond to environmental changes.
Predict what would happen if a DNA sequence had a mutation in a gene coding for an essential protein.
The protein structure could be altered, potentially changing its function and affecting cellular processes.
Explain how a change in one codon could impact the resulting protein.
It could change one amino acid (missense mutation), create a stop codon (nonsense mutation), or have no effect (silent mutation), altering protein function.
Predict what would happen if a structural protein in a muscle cell were misfolded.
Muscle cells could lose function or structure, impairing movement or tissue integrity.
Evaluate the potential impact of a mutation in a protein-coding gene critical for life.
It could be lethal, reduce cellular function, or cause disease depending on the protein’s role.
Predict the effect on an organism if multiple cells fail to produce a key protein.
The organism could experience system failure, disease, or death, depending on the protein’s importance.