DNA
Which statement best describes the primary role of DNA in a eukaryotic cell?
A. DNA provides energy for cellular activities.
B. DNA stores and transmits genetic information that directs protein synthesis.
C. DNA transports materials into and out of the nucleus.
D. DNA forms the structural components of cell membranes
B. DNA stores and transmits genetic information that directs protein synthesis.
A mutation that changes one nucleotide in a gene may:
A. Always cause immediate cell death.
B. Never affect the organism’s phenotype.
C. Change a single amino acid in a protein or have no effect depending on the codon.
D. Remove an entire chromosome from the cell.
C. Change a single amino acid in a protein or have no effect depending on the codon.
During transcription, which molecule is produced from a DNA template?
A. Ribosomal RNA (rRNA)
B. Messenger RNA (mRNA)
C. Transfer RNA (tRNA)
D. DNA polymerase
B. Messenger RNA (mRNA)
A gene is best defined as:
A. A protein made by ribosomes.
B. A specific sequence of nucleotides that codes for a functional product.
C. A membrane-bound organelle that stores proteins. D. A lipid molecule in the cell membrane.
B. A specific sequence of nucleotides that codes for a functional product.
A cell with 2n = 46 undergoes mitosis. Each daughter cell will have:
A. 23 chromosomes
B. 46 chromosomes
C. 92 chromosomes
D. 12 chromosomes
B. 46 chromosomes
Which process produces two identical daughter DNA molecules from one original DNA molecule?
A. Transcription
B. Translation
C. DNA replication
D. Meiosis
C. DNA replication
A frameshift mutation caused by a single-nucleotide insertion in a coding region is likely to:
A. Substitute one amino acid but leave the rest of the protein unchanged.
B. Change the reading frame and alter many downstream amino acids.
C. Only affect noncoding introns.
D. Always create a beneficial protein.
B. Change the reading frame and alter many downstream amino acids.
Translation occurs at which cellular structure?
A. Golgi apparatus
B. Mitochondrion
C. Ribosome
D. Nucleus
C. Ribosome
A scientist observes that a recessive trait appears in the children of two parents who do not show the trait. Which genetic explanation is most likely?
A. The trait is caused by a dominant allele in both parents.
B. Each parent is heterozygous for the recessive allele, and children inherited both recessive alleles.
C. The trait skipped a generation due to environmental factors only.
D. The parents must both be homozygous recessive.
B. Each parent is heterozygous for the recessive allele, and children inherited both recessive alleles.
In a Punnett square predicting a monohybrid cross of two heterozygous parents (Aa × Aa), what fraction of offspring are expected to express the recessive phenotype?
A. 1/4
B. 1/2
C. 3/4
D. 0
A. 1/4
Which of the following correctly pairs a nucleotide base in DNA?
A. Adenine with Cytosine
B. Guanine with Thymine
C. Adenine with Thymine
D. Cytosine with Uracil
C. Adenine with Thymine
In humans, cystic fibrosis is caused by mutations in a single gene. If a child has cystic fibrosis but neither parent shows symptoms, which inheritance pattern fits this observation?
A. Autosomal dominant with incomplete penetrance
B. X-linked recessive
C. Autosomal recessive
D. Mitochondrial inheritance
C. Autosomal recessive
A researcher measures mRNA levels for Gene X in liver and muscle cells and finds higher mRNA levels in liver cells. The most likely interpretation is:
A. Gene X is only present in liver cell DNA.
B. Gene X is expressed at higher levels in liver cells, so more of its protein may be produced there.
C. Liver cells do not use Gene X at all.
D. mRNA levels cannot be used to infer gene expression.
B. Gene X is expressed at higher levels in liver cells, so more of its protein may be produced there.
Which experimental evidence would best support that a specific gene codes for an enzyme required in a metabolic pathway?
A. Observing that the gene is transcribed in all cell types.
B. Showing that organisms lacking the gene cannot carry out the specific biochemical step, and adding back the gene restores the step.
C. Finding that the gene sequence is similar to a gene in another species.
D. Measuring increased ATP levels when the gene is present.
B. Showing that organisms lacking the gene cannot carry out the specific biochemical step, and adding back the gene restores the step.
What specialized cells are involved in Meiosis?
reproductive cells - sperm and egg
Which statement explains why different cell types in the same multicellular organism can look and function differently?
A. Each cell contains different DNA sequences.
B. Cells contain different organelles entirely.
C. Different genes are expressed (turned on or off) in each cell type.
D. Only some cells undergo DNA replication.
C. Different genes are expressed (turned on or off) in each cell type.
Which result would best support the claim that a change in a single gene causes a visible change in phenotype?
A. The phenotype varies randomly among clones with identical genomes.
B. Knocking out the gene in multiple individuals reproduces the phenotype; reintroducing the gene restores the original phenotype.
C. The phenotype appears only under extreme temperature changes.
D. The phenotype is present in unrelated species with no shared gene sequences.
B. Knocking out the gene in multiple individuals reproduces the phenotype; reintroducing the gene restores the original phenotype.
What are the phases of mitosis?
prophase, metaphase, anaphase, and telophase
Which observation would most directly support the idea that genes influence traits through coding for proteins?
A. The gene and protein are located on the same chromosome.
B. Changes in the gene sequence correspond to predictable changes in the amino-acid sequence of its protein product and to changes in phenotype.
C. The gene is highly conserved across many species.
D. The protein and DNA are both present in the nucleus.
B. Changes in the gene sequence correspond to predictable changes in the amino-acid sequence of its protein product and to changes in phenotype.
What are all of the phases of the cell cycle?
interphase, mitosis, cytokinesis