Your dog's Genetics and Inheritance
True or False?
The presence of the SRY gene guarantees that an individual will develop testes and male characteristics.
False — SRY initiates male development, but other genes and hormones are also required.
What does it mean that DNA is semi conservative?
A) Each new DNA molecule is made entirely of newly synthesized strands.
B) Each new DNA molecule is composed of one parental strand and one new strand.
C) Each DNA molecule randomly incorporates fragments of old and new DNA.
D) DNA strands replicate without the use of a template strand.
B) Each new DNA molecule is composed of one parental strand and one new strand.
What is the function of the enzyme topoisomerase?
A) joins Okazaki fragments
B) unwinds DNA
C) prevents overwinding
D) lays RNA primers
C) prevents overwinding
In a repressible operon, such as the trp operon, what is required for the repressor to bind to the operator and block transcription?
A) A promoter sequence
B) RNA polymerase
C) A corepressor molecule
D) A ribosome
C) A corepressor molecule
What is the result of a frameshift mutation?
A) It changes only one amino acid in the protein sequence.
B) It shifts the reading frame, often resulting in a nonfunctional protein.
C) It has no effect on the protein sequence.
D) It adds extra codons without affecting protein function.
B) It shifts the reading frame, often resulting in a nonfunctional protein.
In a pedigree, if a trait is passed from an affected mother to all of her children, but an affected father passes it to none, this suggests:
A) Autosomal recessive inheritance
B) X-linked dominant inheritance
C) Mitochondrial inheritance
D) Y-linked inheritance
Answer: C) Mitochondrial inheritance
What was the key conclusion of the Hershey-Chase experiment involving bacteriophages labeled with radioactive sulfur (³⁵S) and phosphorus (³²P)?
A) Proteins are the hereditary material because they enter bacterial cells.
B) DNA is the hereditary material because only ³²P-labeled material entered bacterial cells.
C) Both protein and DNA enter bacterial cells equally.
D) RNA is the hereditary material, not DNA or protein.
B) DNA is the hereditary material because only ³²P-labeled material entered bacterial cells.
What is the function of the enzyme Helicase?
A) joins Okazaki fragments
B) unwinds DNA
C) prevents overwinding
D) lays RNA primers
B) unwinds DNA
What is the trp operon?
a group of genes that work together to produce the amino acid tryptophan
it's normally on, but can be switched off when tryptophan is abundant
What happens in a nonsense mutation?
A) A codon is changed to a stop codon, causing the protein to be too long.
B) A codon is changed to a stop codon, causing the protein to be shortened.
C) The amino acid sequence of the protein is unchanged.
D) The protein folds incorrectly but remains functional.
B) A codon is changed to a stop codon, causing the protein to be shortened.
Explain why males are more likely to express X-linked recessive traits than females.
Males only have one X chromosome, so a single recessive allele will be expressed. Females have two X chromosomes, so they need two copies of the recessive allele to express the trait.
Why do eukaryotic chromosomes get shorter with each round of DNA replication, and how do some cells counteract this issue?
A) DNA polymerase degrades DNA ends intentionally; helicase repairs them.
B) RNA primers are added too late; ligase prevents shortening.
C) DNA polymerase cannot fully replicate the 5′ end of the leading strand; topoisomerase fixes this in all cells.
D) DNA polymerase cannot fully replicate the 3′ end of the lagging strand; telomerase extends these ends in specific cells.
D) DNA polymerase cannot fully replicate the 3′ end of the lagging strand; telomerase extends these ends in specific cells.
What is read and what is generated in transcription vs translation?
Transcription: reads DNA, produces pre-mRNA
Translation: reads mRNA, produces protein
What causes a repressor protein to remain bound to the operator in a repressible operon like the trp operon?
A) The absence of RNA polymerase
B) Binding of a corepressor molecule, which activates the repressor
C) Mutation in the operator preventing repressor release
D) High levels of transcription factors
B) Binding of a corepressor molecule, which activates the repressor
Which of the following concepts does NOT support Lamarck's theory of evolution?
A) Traits acquired during an organism's lifetime, like muscle development or scars, are passed to offspring.
B) Natural selection drives the evolution of species based on genetic variation.
C) Inherited traits, not acquired traits, are passed to the next generation.
D) The environment can influence an organism’s traits over generations.
A) Traits acquired during an organism's lifetime, like muscle development or scars, are passed to offspring.
Transcribe the lagging strand of DNA according to this template DNA:
go to the slides!
!!!
Which of the following best explains why telomerase activity is often elevated in cancer cells?
A) Cancer cells require shorter chromosomes to replicate faster.
B) Telomerase suppresses cell division, preventing uncontrolled growth.
C) Cancer cells activate telomerase to maintain chromosome length and divide indefinitely.
D) Telomerase triggers apoptosis, which helps cancer cells survive chemotherapy.
C) Cancer cells activate telomerase to maintain chromosome length and divide indefinitely.
During DNA replication, what would most likely occur if DNA ligase were nonfunctional?
A) The DNA helix would fail to unwind at the origin.
B) RNA primers would not be removed from the lagging strand.
C) Okazaki fragments on the lagging strand would remain unconnected.
D) DNA polymerase would be unable to add nucleotides to the leading strand.
C) Okazaki fragments on the lagging strand would remain unconnected.
The enzyme Ligase: joins Okazaki fragments
Which of the following best describes the transcriptional state of a repressible operon like the trp operon?
A) It is normally off and requires an inducer to turn on transcription.
B) It is normally on but can be turned off when a repressor binds with a corepressor.
C) It is always on unless RNA polymerase is inhibited.
D) It requires an activator and inducer to initiate transcription.
B) It is normally on but can be turned off when a repressor binds with a corepressor.
What is the consequence of a nonsense mutation in a coding sequence?
A) It results in the addition of an amino acid to the protein chain.
B) It causes premature termination of protein synthesis, producing a truncated protein.
C) It causes the entire protein to be translated into RNA instead of amino acids.
D) It results in the substitution of one amino acid with another without affecting protein function.
B) It causes premature termination of protein synthesis, producing a truncated protein.
Translate the template DNA strand to the corresponding mRNA strand
~~~ go to the slides!
!!!
What is the primary role of telomerase in eukaryotic cells?
It synthesizes new DNA at the ends of chromosomes to prevent shortening.
Where does transcription occur in the cell of eukaryotes?
happens in nucleus.
Is tryptophan important? Why?
Tryptophan is an essential amino acid
your body can't produce it and you must get it from your diet
plays a vital role in protein synthesis and is a precursor to serotonin and melatonin that influence mood, sleep, and other bodily functions
THE FOUR Natural Selection prerequisites
Variation in traits
Traits must be heritable
Differential survival/reproduction
Leads to adaptation over generations