2018 Biology Keystone Exam Prep

Which condition would most likely result in an increase in the phenotypic variation within a population?

A mutation leads to individuals with genetic differences.

Which action must occur for an enzyme to catalyze a chemical reaction?

A substrate must bind to an active site of the enzyme.

Which statement correctly describes how a protein is formed?

Amino acids are bonded together in a long chain to form a new molecule.

Which statement best describes how channel and carrier proteins in the plasma membrane are similar?

Both allow for the flow of molecules into and out of a cell.

Carbon can combine with many different elements but frequently combines with oxygen, hydrogen, and nitrogen to form organic molecules. Which statement best explains why carbon is able to form a large number of different molecules?

Carbon can form four covalent bonds.

Which statement best describes the outcomes of both meiosis and mitosis?

Cell division results in daughter cells that contain DNA.

Lipase is an enzyme that breaks down lipids in the digestive system of humans. It functions best at a pH range of 4.0 to 5.0. When a person takes an antacid tablet to relieve heartburn, the antacid increases the pH to around 7 in certain areas of the digestive system. Which initial effect would most likely be caused by a change in pH?

Fewer lipids would be digested.

Which statement best describes how geographic isolation can contribute to land animal speciation?

Geographic isolation physically separates populations and prevents them from interacting.

Ash from a volcanic eruption decreases the amount of available solar energy for a region. Which statement describes how a decrease in available sunlight will most likely affect ecosystems of this region?

Producer populations will decrease, causing a decrease in consumer populations.

A cell in the leaf of a green plant performs both photosynthesis and cellular respiration, often at the same time. Which statement best describes how these processes are related to each other?

Products of one process are used as some of the reactants for the other process.

An inversion occurs along part of a chromosome. How does the inversion most likely affect the region in which it occurs?

The information in the region is read differently during transcription.

A scientist observed that during the course of a chemical reaction the number of ATP molecules was reduced. What did the scientist most likely learn from the observation?

The reaction required an input of energy.

In order to study genetic mutations, scientists must study genetic material. Which statement describes the genetic material scientists are most likely studying?

They study chromosomes that contain genes, which are DNA segments.

At a point in the cell cycle, chromosomes have aligned near the middle of a cell. Which sequence of events will the cell need to complete to produce two identical daughter cells?

anaphase -> telophase -> cytokinesis

Many scientists have concluded that whales and dolphins have a more recent, common ancestor than do whales and sharks. Which characteristic most likely allowed scientists to make this conclusion?

anatomical structure

Tadpoles grown in ponds with high densities of tadpoles have lower survival and growth rates than tadpoles grown in ponds with lower densities of tadpoles. Which interaction between tadpoles grown in high-tadpole-density ponds would most likely cause the decreased survival and growth rates?

competition

Which characteristic is shared by both prokaryotes and eukaryotes?

contain genetic material

Which set of ecological organization levels is most likely to contain the largest variety of species?

multiple biomes in a biosphere