Unit 2 AP Biology Insta-Review (Cell Structure & Function)

Which organelle is responsible for the digestion of macromolecules?

• Golgi Bodies

• Lysosome

• Rough ER

• Smooth ER

Answer explanation

The lysosome is a sac with hydrolytic enzymes. These hydrolytic enzymes will undergo hydrolysis to digest macromolecules.

What binds to the small subunit of a ribosome?

• DNA

• mRNA

• rRNA

• tRNA

Answer explanation

The ribosome is arranged with the large subunit on "top" and the small subunit on "bottom". The large subunit has the A, P, and E sites for the tRNA and the small subunit binds to the mRNA for translation.

Which is the easiest to cross the membrane unassisted?

• Small, nonpolar

• Small, polar

• Large, nonpolar

• Large, polar

Answer explanation

The membrane is composed of phospholipids which makes the membrane nonpolar. In order for a material to pass through the membrane unassisted, it needs to be small to fit between the phospholipids and nonpolar to "dissolve" in the membrane to pass through.

Which cell is more efficient?

• Sphere

  SA: 36 pi 

  V: (108/3)pi 

• Cube

  SA: 24

  V: 8

Answer explanation

The sphere has a SA/V ratio of 1 and the cube has a SA/V ratio of 3.

The larger SA:V ratio is more efficient

Tags

NGSS.MS-ETS1-1

NGSS.MS-ETS1-2

Where does the synthesis of cellular ATP occur?

• Cristae

• Matrix

• Stroma

• Thylakoid

Answer explanation

Don’t get tricked by this question. This question mentions the "cellular ATP" which means the ATP for the cellular processes. These ATP molecules are synthesized during cellular respiration (hence the mitochondrial cristae).

Tags

NGSS.HS-LS1-7

NGSS.HS-LS2-3

Where does carbon fixation occur?

• Cristae

• Matrix

• Stroma

• Thylakoid

Answer explanation

Carbon fixation takes place in the chloroplast, specifically in the stroma of the chloroplast. This is the cytosol of the chloroplast. The carbon fixation step is involved in the Calvin Cycle.

Which organelle synthesizes cytosolic proteins?

• Free Ribosomes

• Golgi Bodies

• Rough ER

• Smooth ER

Answer explanation

Cytosolic proteins are proteins found in the cytosol. This means that the ribosome will not attached to a membrane since the protein is not in or surrounded by membrane. These ribosomes are called free ribosomes.

Which of the following aids in turgor pressure in plants?

• Chloroplast

• Mitochondria

• Nucleus

• Vacuole

Answer explanation

Turgor pressure results from the water storage in the central vacuole when the plant is in a hypotonic environment. This allows the plant cell to be firm.

Which of the following cells is most efficient?

Note: SA = surface area, V = volume

• SA: 4, V: 1

• SA: 3, V: 2

• SA: 2, V: 3

• SA: 1, V: 4

Answer explanation

The most efficient cell is the cell with the highest surface area to volume ratio.

A. 4/1 = 4

B. 3/2 = 1.5

C. 2/3 = 0.67

D. 1/4 = 0.25

What makes up ribosomes?

• mRNA & proteins

• mRNA & tRNA

• rRNA & proteins

• rRNA & tRNA

Answer explanation

rRNA is the ribosomal RNA. This RNA folds with proteins to create the large and small subunits of the ribosomes.