Biotechnology Vocabulary
What is the DNA sequence that can increase the rate of gene transcription, often over a considerable distance?
Enhancer
A change in the lines of descent over time, a change in the genetic composition of a population.
Evolution
A cell has all the necessary DNA and RNA polymerase, but the gene isn’t being expressed because transcription hasn’t started. What step is blocked?
The promoter is preventing transcription initiation because RNA polymerase cannot bind properly.
A new mutation arises in a gene that gives a survival advantage during drought conditions. Over many generations, this allele becomes more common. Which process is this an example of?
Natural Selection
How many mass extinctions have occurred?
5
What is the specific DNA sequence that acts as the starting point for gene transcription?
Promoter
Finding others attractive based on what is seen, heard, or smelled.
Behavioral Isolation
Doctors analyze a child’s hemoglobin gene by cutting the DNA with restriction enzymes and running it through a gel. The results show two different band sizes — one matching the normal allele and one matching the sickle-cell mutation — revealing the child is a genetic carrier. What tool was used to find this mutation?
Gel Electrophoresis.
A small population of flowers is wiped out by a storm, leaving only a few survivors with certain alleles. Over generations, these alleles dominate the population. What evolutionary force is responsible?
Genetic Drift (Bottleneck Effect)
List the 5 ways a population is in equilibrium.
Large population size
Isolation
No mutations
No selection
Random mating
What is the segment of DNA that acts as a "switch" and as a binding site for repressor proteins, which control gene expression?
Operator
The embryo will not develop properly, and a spontaneous abortion occurs.
Hybrid Inviability
A patient’s liver cells are dividing rapidly, and most of their DNA is tightly packaged into condensed chromatin. Doctors notice that certain liver-specific genes are barely expressed. Explain why this happens.
Tightly packaged DNA prevents transcription factors and RNA polymerase from accessing the genes, so transcription is blocked.
A few birds migrate from one island to another, introducing new flower color alleles to the resident population. Over time, the gene frequencies change. What evolutionary process is occurring?
Gene flow
A few individuals from a mainland bird population colonize a small island. Over generations, their descendants have very different beak shapes than the mainland birds, even though they are the same species. What evolutionary process is likely responsible, and why?
Founder Effect
What are the molecular scissors that cut double-stranded DNA at specific recognition sites?
Restriction Enzyme
The environment is rapidly changing, most of the individuals in the middle die off with only those in the two extreme ends surviving.
Disruptive Selection
A mutation destroys the Lac repressor’s ability to bind lactose. Predict the state of the operon when lactose is present.
Repressor stays bound to operator → operon stays off.
Fossil evidence shows horses gradually increasing in size over millions of years in response to changing environmental conditions. Which type of selection does this represent?
Directional Selection
Human babies born extremely small or extremely large have lower survival rates, while those of average weight survive best. Which type of natural selection is this?
Stabilizing selection
What is the laboratory technique used to detect and identify a specific protein in a complex mixture by separating proteins via electrophoresis?
Western Blot
A spread of traits that confer advantages to an individual during courtship and competition for a mate
Nonrandom Mating
A patient’s genetic test reveals a mutation in a regulatory region of their DNA. The mutation prevents an activator protein from binding to an enhancer near an important metabolic gene. Even though RNA polymerase is still present in the cell, doctors notice the gene’s expression is far lower than normal. Explain why this happens.
The gene’s transcription is greatly reduced because the activator cannot bind the enhancer to help RNA polymerase initiate efficiently.
Two frog populations live in the same lake but reproduce at different times of the year. Over generations, they no longer interbreed. What type of isolating mechanism caused this?
Temporal Isolation
A person eats a sugary meal, causing their blood glucose levels to rise. In response, the level of cAMP in their liver cells drops. Explain why this happens and what effect it has on glycogen breakdown.
High glucose triggers a decrease in cAMP, slowing glycogen breakdown in the liver.