Sat Past Questions And Answers
A species of seagull migrates into the region in which a crab population lives. This type of seagull has never lived in this particular environment before. The seagulls eat crabs, and begin to prey on the crab population. The smallest of the crabs are able to successfully hide under rocks and avoid being eaten by the seagulls. The largest of the crabs are too big to fit inside of the seagulls' beaks, so the seagulls learn not to try to eat them. Over time, the seagulls prey on the medium sized crabs, and only the smallest and largest members of the initial crab population survive. Which type of selection does the described situation model?
- A. Convergent selection
- B. Directional selection
- C. Random selection
- D. Disruptive selection
What are the three types of RNA most important to polypeptide formation?
- A. tRNA, rRNA, and miRNA
- B. mRNA, tRNA, and rRNA
- C. None of these
- D. mRNA, snRNA, and rRNA
What is the role of DNA helicase in DNA replication and DNA transcription?
- A. DNA helicase replaces the RNA primers with DNA nucleotides in DNA replication. Helicase has no use in DNA transcription.
- B. DNA helicase disrupts the hydrogen bonding between the two strands of DNA and exposes the insides of the DNA helix, allowing for other enzymes to replicate or transcribe the single-stranded DNA.
- C. None of these
- D. DNA helicase relieves the torsional strain and supercoiling that DNA undergoes during replication/transcription, and in doing so helps maintain the DNA double helix.
If a structural gene in an organism's genome is comprised of 33% adenine nucleotides, what percentage of the gene is comprised of cytosine nucleotides?
- A. 22%
- B. 33%
- C. It cannot be determined from the given information.
- D. 17%
A man expresses a certain X-linked recessive genetic disorder. Which of the following must be true? I. His father passed on the allele for the disorder II. His mother passed on the allele for the disorder III. His mother expresses the disorder
- A. None of these
- B. I only
- C. II and III only
- D. II only
The average of x,x+20,x?1, and x?15 is 10. Find the value of the largest number.
- A. 12
- B. ?9
- C. 29
- D. 10
The role of an enzyme in a chemical reaction is to change which of the following?
- A. The pH at which the reaction occurs
- B. The temperature at which the reaction occurs
- C. The activation energy of the reaction
- D. The type of reaction
In which type of speciation does a new species evolve from an ancestral species while inhabiting the same area as the ancestral species?
- A. Allopatric
- B. Sympatric
- C. Convergent
- D. Peripatric
Determine the mean of the numbers: [9,?6,?3,?11]
- A. The mean does not exist.
- B. 29/4
- C. ?11/4
- D. 11/4
Which three phases are included in Interphase?
- A. M, S, and G
- B. G0, G1, and G2
- C. G1, S, and G2
- D. M, G0, S