Biology Final

A scientist observes that, when the pH of the environment surrounding an enzyme is changed, the rate the enzyme catalyzes a reaction greatly decreases. Describe how a change in pH can affect an enzyme.

A pH change can cause the enzyme to change its shape

A protein in a cell membrane changed its shape to move sodium and potassium ions against their concentration gradients. What molecule was most likely used by the protein as an energy source?

ATP

Water is the most abundant molecule found in living organisms. Most mammals are approximately 70% water by weight. About two-thirds of this water is present inside cells. The other one-third is present outside cells (e.g. In blood plasma or other body fluids). Why is water so important to cells?

Almost all the he chemical reactions in life processes occur in solutions with water. All chemical reactions occur in a water base environment.

Photosynthesis and cellular respiration are two major processes of carbon cycling in living organisms. Describe one similarity between photosynthesis and cellular respiration

Both include reactions and transform energy.

How does the size of a eukaryotic organism normally compare to the size of a prokaryotic organism?

Eukaryotes are usually much larger than prokaryotes. Eukaryotes are more complex

Which molecules are the reactants for cell respiration?

Glucose and oxygen

Which cell part is analogous to the packaging and shipping department of a factory?

Golgi apparatus. It is the warehouse of the cell.

Describe how carbon's ability to form four bonds makes it uniquely suited to form macromolecules.

It forms covalent bonds with other carbon atoms.

Substance A is converted to substance B in a metabolic reaction. Describe the role of an enzyme during this reaction.

It speeds up the reaction without being consumed.

Using a microscope, a student observes a small, green organelle in a plant cell. Which energy transformation most likely occurs first within the observed organelle?

Light to chemical

What do lipids provide in organisms?

Long-term energy storage.

Living organisms can be classified as prokaryotes or eukaryotes. Which two structures are common to both prokaryotic and eukaryotic cells?

Plasma membrane and cytoplasm. Plasma membrane is the gatekeeper and the cytoplasm holds chemical reactions.

Carbohydrates and proteins are two types of macromolecules. Which functional characteristic of proteins distinguishes them from carbohydrates?

The ability to catalyze biochemical reactions. An enzyme is a protein catalyst.

What characteristic is shared by all prokaryotes and eukaryotes?

The ability to store hereditary information. All cells reproduce.

Alveoli are microscopic air sacs in the lungs of mammals. Which statement best describes how the structure of the alveoli allows the lungs to function properly?

They increase the surface area of the lungs, allowing efficient gas exchange. Carbon dioxide and oxygen are exchanged in the lungs

What is an effect of the low density of frozen water in a lake?

When water in a lake freezes, it floats, providing insulation for organisms below. Water in the solid state is less dense than the liquid, so it floats.