BR 56 -Biomolecules & Enzymes

1.

Multiple Choice

2 mins

1 pt

Proteins and polysaccharides are polymers. These polymers are formed by dehydration synthesis. Which statement correctly identifies a difference in the structure of proteins and polysaccharides?

Only polysaccharides are made of repeating units of cytosine, adenine, guanine, and thymine.

Only proteins are formed from amino acids joined by peptide bonds.

Only polysaccharides can be folded and twisted to very specific shapes.

Only proteins can be large molecules with thousands of subunits.

2.

Multiple Choice

45 sec

1 pt

Which of these best represents a fatty-acid molecule?

3.

Multiple Choice

1 min

1 pt

Overheating an enzyme results in the enzyme’s loss of —

net electrical charge

ability to catalyze a reaction

storage of a large amount of chemical energy

storage of inherited information

4.

Multiple Choice

1 min

1 pt

Which of the following biological molecules is correctly paired with one of the functions it primarily serves in living cells?

nucleic acids - store genetic information

lipids - catalyze chemical reactions

carbohydrates - component of cytoskeleton

proteins - long term energy storage

5.

Multiple Choice

2 mins

1 pt

In red blood cells, the compound carbonic anhydrase increases the rate at which carbon dioxide is converted to bicarbonate ions for transport in the blood. In red blood cells, carbonic anhydrase acts as which of the following?

an enzyme

a hormone

a lipid

a sugar

6.

Multiple Choice

1 min

1 pt

Which best describes how enzymes function in the body?

Enzymes are converted into products by the reactions they catalyze.

Enzymes lower the activation energy of reactions.

One enzyme can catalyze many different reactions.

An enzyme is used once and then destroyed by the cell.

7.

Multiple Choice

1 min

1 pt

Which statement describes the major role of lipids within a cell?

They cause DNA to replicate.

They move RNA in the cytoplasm.

They catalyze chemical reactions in the cell.

They are the main components of membranes.

8.

Multiple Choice

1 min

1 pt

Most cellular activities are processes regulated (controlled) by the action of —

carbohydrates

enzymes

lipids

polysaccharides

9.

Multiple Choice

1 min

1 pt

Proteins and nucleic acids both contain the element nitrogen, but only proteins contain which of the following elements?

carbon

hydrogen

phosphorous

sulfur

10.

Multiple Choice

2 mins

1 pt

Certain biomolecules contain information in their structure that can be used to determine the relatedness of two different species. Which set below is studied for this information?

lipids and proteins

proteins and carbohydrates

lipids and carbohydrates

nucleic acids and proteins

11.

Multiple Choice

1 min

1 pt

A diagram of a protein molecule is shown. The units labeled “X” which bond together to form the protein molecule are called -

amino acids.

monosaccharides.

fatty acids.

nucleotides.

12.

Multiple Choice

2 mins

1 pt

Enzymes are proteins that help increase the rate of chemical reactions inside cells. These proteins are composed of many simpler molecules called amino acids. Which of the following suggests that the shape of an enzyme determines the enzyme’s function?

Enzymes are specific to a substrate.

Enzymes can operate in a wide range of conditions.

Enzymes are activated by neighboring molecules.

Enzymes can be found in all life-forms.

13.

Multiple Choice

1 min

1 pt

Proteins and nucleic acids serve a wide variety of functions in the cell, and they are both made in a similar way by joining together a sequence of repeating subunits. For this reason, both of these organic molecules are referred to as -

Polymers

Lipids

Micronutrients

Enzymes

14.

Multiple Choice

45 sec

1 pt

Which best describes the role of enzymes in a chemical reaction?

absorb excess energy

release unused energy

increase the reaction rate

regulate product reactivity

15.

Multiple Choice

45 sec

1 pt

Which of the following is the main reason that humans need to include carbohydrates in their diet?

Carbohydrates are broken down in cells for energy.

Carbohydrates combine to form many different proteins.

Carbohydrates act as catalysts to speed up chemical reactions.

Carbohydrates are the building blocks for cell growth and repair.

16.

Multiple Choice

1 min

1 pt

Some bacteria contain a substance called nitrogenase. Nitrogenase catalyzes the chemical reaction that converts atmospheric nitrogen (N₂) into ammonia (NH₃). Nitrogenase is an example of which of the following?

a sugar

an enzyme

a nucleotide

an amino acid

17.

Multiple Choice

45 sec

1 pt

In the diagram show above, the dipeptide is the -

enzyme

substrate

product

active site

18.

Multiple Choice

45 sec

1 pt

In the diagram above, the substance labeled X is most likely -

an enzyme

water

ATP

oxygen

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