Cell Biology Benchmark Practice Questions

1. Which of the following describe the organelles that plant cells have, that animals cells do not?

Nucleus, cell membrane, lysosomes

Golgi apparatus, mitochondria, chloroplasts

Chloroplasts, cell wall (made of cellulose), large central vacuole

Chloroplasts, mitochondria, nuclus

Only plants have a chloroplast because only plants can perform photosynthesis. Plant cells also have a cell wall so their bodies can be more rigid to grow upwards towards sunlight. (Animal cells do not have cell walls because animals can move, and a cell wall is too rigid to allow a lot of movement.) Plant cells also use a large central vacuole to fill with water and nutrients.

Explanation

Only plants have a chloroplast because only plants can perform photosynthesis. Plant cells also have a cell wall so their bodies can be more rigid to grow upwards towards sunlight. (Animal cells do not have cell walls because animals can move, and a cell wall is too rigid to allow a lot of movement.) Plant cells also use a large central vacuole to fill with water and nutrients.

2. Which cellular organelle is responsible for packaging the proteins that the cell secretes?

Cytoskeleton

Golgi apparatus

Lysosome

Cell membrane

The golgi apparatus is often described as "the post office" of the cell. After a protein is assembled by a ribosome, tagged or modified by the endoplasmic reticulum, it is "driven" by a vesicle to the gologi apparatus. The golgi then decides where it needs to go, and packages it appropriately for delivery by another vesicle.

Explanation

The golgi apparatus is often described as "the post office" of the cell. After a protein is assembled by a ribosome, tagged or modified by the endoplasmic reticulum, it is "driven" by a vesicle to the gologi apparatus. The golgi then decides where it needs to go, and packages it appropriately for delivery by another vesicle.

3. The cell membrane of the red blood cellwill allow water, oxygen, carbon dioxide, and glucose to pass through. Because other substances are blocked from entering, this membrane is called:

Perforated.

Semi-permeable.

Non-conductive.

Permeable.

Permeable means "to allow materials to pass through". The prefix semi- means "partly." The cell membrane is described as semi-permeable because it allow SOME materials to pass through, but not all. Sometimes this is also called "selective-permeability"

Explanation

Permeable means "to allow materials to pass through". The prefix semi- means "partly." The cell membrane is described as semi-permeable because it allow SOME materials to pass through, but not all. Sometimes this is also called "selective-permeability"

4. The first stage of photosynthesis in the chloroplast is

Light-dependent

Temperature-dependent

Glucose-driven

ATP-driven

The first reaction that must happen is the light dependent, because light energy is what fuels the whole process of photosynthesis. The light is used (along with H2O) to create NADPH and ATP to fuel the next reaction. (Calvin Cycle)

Explanation

The first reaction that must happen is the light dependent, because light energy is what fuels the whole process of photosynthesis. The light is used (along with H2O) to create NADPH and ATP to fuel the next reaction. (Calvin Cycle)

5. Eukaryotic cells are differentiated from prokaryotic cells because eukaryotic cells

Are much smaller.

Have permeable membranes.

Have a higher rate of reproduction.

Have nuclei.

Eukaryotes store their DNA in a nucleus, but prokaryotes do not. The other options are incorrect because prokaryotes are actually smaller than eukaryotes, ALL cells have permeable membranes, and all cells can reproduce at similar rates.

Explanation

Eukaryotes store their DNA in a nucleus, but prokaryotes do not. The other options are incorrect because prokaryotes are actually smaller than eukaryotes, ALL cells have permeable membranes, and all cells can reproduce at similar rates.

6. In aerobic respiration, the Krebs cycle (citric acid cycle) takes place in

Mitochondria

Cytoplasm

Nucleus

Cell membrane

The main steps of cellular respiration are the Kreb's Cycle and Electron Transport chain, which both require energy and occur in the mitochondria. The function of the mitochondria is to release energy from food, which is precisely what cellular respiration does!

Explanation

The main steps of cellular respiration are the Kreb's Cycle and Electron Transport chain, which both require energy and occur in the mitochondria. The function of the mitochondria is to release energy from food, which is precisely what cellular respiration does!

7. What causes tomatoes to ripen much more slowly in a refrigerator than they do if left on a table at room temperature?

Tomatoes need sunlight to ripen.

Humidity accelerates the ripening process.

Low temperatures reduce the action ofripening enzymes.

Enzymes produced by bacteria inhibit ripening.

Recall that TEMPERATURE has a negative effect on enzymes. Heat destroys enzymes and renders them completely useless, but cold temperatures just slow enzymes down. In this case, by putting tomatoes in the fridge you are exposing the enzymes in them to cold, slowing down the ripening process.

Explanation

Recall that TEMPERATURE has a negative effect on enzymes. Heat destroys enzymes and renders them completely useless, but cold temperatures just slow enzymes down. In this case, by putting tomatoes in the fridge you are exposing the enzymes in them to cold, slowing down the ripening process.

8. There are many different enzymes located in the cytoplasm of a single cell. How is a specific enzyme able to catalyze a specific reaction?

Different enzymes are synthesized in specific areas of the cytoplasm.

Most enzymes can catalyze many different reactions.

An enzyme binds to a specific substrate (reactant) for the reaction catalyzed.

Enzymes are transported to specific substrates (reactants) by ribosomes.

Each enzyme can only catalyze (speed up) one reaction. That is because the SHAPE of an enzyme must match perfectly to the substrate it wants to help. (Like a lock and key). Enzymes will only bind to the substrate that fits into them.

Explanation

Each enzyme can only catalyze (speed up) one reaction. That is because the SHAPE of an enzyme must match perfectly to the substrate it wants to help. (Like a lock and key). Enzymes will only bind to the substrate that fits into them.

9. The plasma membrane of a cell consists of

Protein molecules arranged in two layers with polar areas forming the outside of the membrane.

Two layers of lipids organized with the nonpolar tails forming the interior of the membrane.

Lipid molecules positioned between two carbohydrate layers.

Protein molecules with polar and nonpolar tails.

The plasma membrane is made up of a lipid bilayer. Remember, the prefix bi- means 2, so this literally means two layers of lipids. Each lipid has a hydrophobic tail, which is also called non-polar - meaning doesn't like water! Since cells are surrounded by water, the lipids tails face inward towards each other.

Explanation

The plasma membrane is made up of a lipid bilayer. Remember, the prefix bi- means 2, so this literally means two layers of lipids. Each lipid has a hydrophobic tail, which is also called non-polar - meaning doesn't like water! Since cells are surrounded by water, the lipids tails face inward towards each other.

10. Which molecule in plant cells first captures the radiant energy from sunlight?

Chlorophyll

Glucose

Carbon dioxide

Chloroplast

Chlorophyll is the pigment that absorbs light energy. It is green in color, and found in the thylakoids of the chloroplasts of plant cells. (The chloroplast itself does not absorb light energy, the pigment chlorophyll does.)

Explanation

Chlorophyll is the pigment that absorbs light energy. It is green in color, and found in the thylakoids of the chloroplasts of plant cells. (The chloroplast itself does not absorb light energy, the pigment chlorophyll does.)

11. Maltose can be broken down into glucose molecules by the enzyme maltase. Which of the following would slow the reaction rate?

Adding maltase

Adding maltose

Removing glucose

Diluting with water

By diluting the solution with water, it makes it more difficult for the enzyme and substrate to find each other. (There is more space for them to have to float through to find each other - for example, say you lose your binder. It would be much easier to find your lost binder if you know you lost it in your bedroom vs. if you lost it at school because the school campus is much bigger than your bedroom.)

Explanation

By diluting the solution with water, it makes it more difficult for the enzyme and substrate to find each other. (There is more space for them to have to float through to find each other - for example, say you lose your binder. It would be much easier to find your lost binder if you know you lost it in your bedroom vs. if you lost it at school because the school campus is much bigger than your bedroom.)

12. The human liver helps to detoxify drugs and alcohol in your body. A cell from liver muscle would probably have an unusually high proportion of

Lysosomes

Smooth endoplasmic reticulum

Nuclei

Chloroplasts

Remember that eukaryotes can form multi-cellular organisms because each cell can be "specialized" - or different to perform different functions. That means what is on the inside of each cell may be different. In the liver, each cell has a large amount of smooth endoplasmic reticulum compared to "normal" cells because the S.E.R.'s function is to detoxify drugs and alcohol. (which is the job of the whole liver!)

Explanation

Remember that eukaryotes can form multi-cellular organisms because each cell can be "specialized" - or different to perform different functions. That means what is on the inside of each cell may be different. In the liver, each cell has a large amount of smooth endoplasmic reticulum compared to "normal" cells because the S.E.R.'s function is to detoxify drugs and alcohol. (which is the job of the whole liver!)