Question

directions: read each question carefully, and record your answers at the bottom of the paper. you may use your notes from your binder, but no phones, laptops, or any other electronic device may be used.

question 1:
how do enzymes affect the reactions in living cells?
a. enzymes change the active site energy of the reaction.
b. enzymes slow the speed of the reaction.
c. enzymes change the temperature of the reaction.
d. enzymes lower the activation energy of the reaction.

question 2:
cells need oxygen and glucose for cellular respiration. the phospholipid bilayer of the cell membrane allows oxygen to freely pass through; however, glucose can’t enter the cell without the help of a special protein. water, produced in cellular respiration, may pass through the phospholipid bilayer or through specialized proteins called aquaporins. this data table provides information about the molecules involved in cellular respiration.

molecule	role	size (nm)	charge of molecule
glucose (solid)	reactant	1.000	partially charged
oxygen (gas)	reactant	0.299	neutral
water (liquid)	product	0.270	partially charged

based on the data, which statement best predicts what types of molecules will be able to pass the cell membrane freely?
a. gases, like carbon dioxide and oxygen, will pass through the cell membrane, but liquids and solids, like glucose and water, will require proteins to pass through the cell membrane.
b. small molecules, like carbon dioxide, oxygen, and water will pass through the cell membrane, but glucose and other large molecules will require proteins to pass through the cell membrane.
c. reactant molecules, like carbon dioxide and glucose, will pass through the cell membrane, but product molecules, like oxygen and water, will require proteins to pass through the cell membrane.
d. neutral molecules, like carbon dioxide and oxygen, will pass through the cell membrane, but partially charged molecules, like glucose and water, will require proteins to pass through the cell membrane.

question 3:
how do the chloroplasts and mitochondria interact to maintain homeostasis in a plant cell?
a. these organelles are both important for the uptake of nutrients from the cell’s exterior.
b. these organelles are both important in the regulated transport of the molecules within cells.
c. these organelles are both important because glucose produced by the chloroplasts enters the mitochondria to be converted into energy.
d. these organelles are both important for the use of cellular genetic information to make proteins.

record answers here

Explanation:

Question 1

Enzymes act as biological catalysts. The key function of enzymes is to lower the activation energy of a chemical reaction, which speeds up the reaction rate. Option A is incorrect as enzymes don't change the active site energy. Option B is wrong because enzymes increase (not slow) reaction speed. Option C is incorrect as enzymes don't change the temperature of the reaction. So the correct answer is D.

From the data table: Carbon dioxide (size 0.330 nm, neutral), oxygen (0.299 nm, neutral), and water (0.270 nm, partially charged) are small molecules. Glucose (1.000 nm, partially charged) is large. The cell membrane allows small molecules to pass freely, while large molecules (like glucose) need proteins. Option A is wrong about water needing proteins. Option C is incorrect about reactant/product classification. Option D is wrong about charge - neutral molecules (CO₂, O₂) and partially charged (water, glucose) - glucose is large. So B is correct.

Chloroplasts perform photosynthesis to produce glucose. Mitochondria perform cellular respiration to convert glucose into energy (ATP). Option A is wrong as their main role isn't nutrient uptake. Option B is incorrect as they aren't mainly for molecule transport. Option D is wrong as they don't use genetic info for protein - making (ribosomes do that). So C is correct.

Answer:

D. Enzymes lower the activation energy of the reaction.

Question 2