WorksheetsMacromolecules, enzymes and properties of water
Total questions: 30
Worksheet time: 51mins
View Figure 1 (if not visible)
View Figure 2 (if not visible)
View Figure 3 (if not visible)
As food travels through the digestive system, it is exposed to a variety of pH levels. The stomach has a pH of 2 due to the presence of hydrochloride acid (HCl), and the small intestine has a pH ranging from 7 to 9. HCl converts pepsinogen into pepsin, an enzyme that digests proteins in the stomach. Which of the following most likely happens to pepsin as it enters the small intestine?
It becomes denatured and inactive.
It begins to replicate.
It's shape changes to engulf large proteins.
It's activity increases to digest more proteins.
What will most likely happen if an appropriate enzyme is added to a chemical reaction?
The reaction rate will increase.
The equilibrium of the reaction will be maintained.
The reaction rate will decrease.
The reaction will stop.
A scientist analyzing an unknown substance has determined that it consists only of carbon, hydrogen and oxygen. During experimentation, she determines that the substance is soluble, or dissolves, in OIL but not in water. Which of the following macromolecules is the unknown substance most likely to be?
carbohydrate
lipid
nucleic acid
protein
Without enzymes, many biological processes would occur too slowly for life to be possible. The graph below shows the activity of two enzymes at various pH values.
What does the graph indicate about enzymes?
A pH close to 7 is optimal for most enzymes.
Each enzyme functions best within a limited pH range.
The pH of a solution has little effect on the activity of an enzyme.
The activity of an enzyme increases as the pH of a solution increases.
Enzymes are important biological molecules that affect the way reactions occur. The graph below shows how a reaction proceeds with and without an enzyme.
Which of the following best describes the difference between the two reactions?
Reaction with enzyme uses less energy
Reaction with enzyme uses more energy
Reactions are the same
Reaction without enzyme uses less energy
Tomatoes left on a countertop will ripen much faster than similar tomatoes placed in a refrigerator. Which of the following best explains the difference in ripening times?
Humidity causes the tomatoes to decompose faster.
Sunlight breaks down the tomato’s skin and exposes it to air.
Lower temperatures reduce the reaction rate of ripening enzymes.
Other foods in the refrigerator release hormones that stop ripening bacteria.
The diagram below shows the relationship between substrate concentration and reaction rate (how fast the reaction goes).
Based on the graph, which of the following accurately describes how substrate concentration changes the reaction rate.
Substrate concentration does not change reaction rate
High substrate concentration has a faster reaction rate
Low substrate concentration has a faster reaction rate
High substrate concentration has a slower reaction rate
If an enzyme solution is saturated (too much) with substrate, the most effective way to obtain an even faster yield (amount) of products is to:
Add more of the enzyme
Boil the solution
Add more substrate
Cool the solution
A florist places a bouquet of white carnations in water containing blue dye. After a time, the flowers turn blue. What are the properties of water that help water travel through the stem of plants?
water’s ability to form crystals
ability of H2O to dissolve NaCl
cohesion and adhesion of water molecules
formation of covalent bonds between hydrogen and oxygen molecules
Water makes up between 70-90% of the weight of most life forms, and nearly all chemicals present in living matter are soluble in it allowing for life to exist. Why is water such a good solvent?
The molecular structure of water is covalent.
The molecular structure of water is adhesive.
The molecular structure of water molecule is polar.
The molecular structure of water allows it to expand when frozen.
Some fish are able to live in lakes during extremely cold winter months. Which statement describes the characteristic of water that plays an important role in allowing fish to live in these cold water lakes?
Water is a versatile solvent, and the temperature is regulated by substances dissolved in the fresh water.
Water forms hydrogen bonds with other water molecules at the surface of the water.
Water freezes and decreases the temperature of the water in the lake.
Water has the ability to moderate temperature.
Water has several properties that make it essential to life. Which property of water is most important for dissolving molecules to deliver nutrients to cells of the human body?
Cohesive properties
Adhesive properties
High specific heat
Universal solvent
Why does ice stay at the top of oceans instead of sinking to the bottom?
Ice is colder than liquid water.
Ice is less dense than liquid water.
Ice is more dense than liquid water.
Ice is warmer than liquid water.
