A hospital pharmacist prepares an IV solution by dissolving 5 g of glucose and 0.9 g of NaCl in 100 mL of water. Assume that NaCl completely dissociates and that the molar masses are:

• Glucose = 180 g/mol

• NaCl = 58.5 g/mol

Based on this, which of the following best describes the osmolarity of the solution and its tonicity relative to blood plasma (which has an osmolarity of ~300 mOsm/L)?

A researcher genetically modifies a eukaryotic cell so that it can no longer synthesize hydrolytic enzymes within lysosomes. Over time, she observes the following effects:

• Undigested food accumulates in vacuoles

• Damaged mitochondria persist within the cytoplasm

• The cell becomes increasingly inefficient in energy use and macromolecule recycling

Which of the following best explains why this mutation would critically impair both survival and homeostasis of the cell?

The image illustrates the endosymbiotic theory, which proposes that mitochondria and chloroplasts originated from free-living prokaryotes engulfed by a host cell. Scientific theories gain credibility when they are falsifiable—i.e., when they make predictions that can be tested and potentially proven wrong.

Which of the following, if discovered, would most strongly falsify the endosymbiotic theory?

Anxious cricket fans may feel their hearts racing during tense moments—this is due to faster electrical activity in the heart.

Refer to the diagram below:

• The bottom graph shows the cardiac action potential of a contractile cell.

• Image B shows the conduction of electrical signals from the SA node through the cardiac muscle.

However, one of the features depicted in Image B is inaccurate. Identify the best option:

Name any two techniques you could use to confirm

the success or failure of the proposed reaction.   

In the image, the cricketer powerfully

swings the bat, a movement that requires rapid and coordinated muscle

contraction. Which

sequence best describes the microscopic events enabling muscle contraction?

List the components of the reaction mixture you

will create to conduct the selected molecular biology technique.

Congratulations! You got all steps right so far

and now have a highly concentrated solution of the required target molecule. List

as bullet points the next steps required to finally obtain a high concentration

of spike protein which you will use in the vaccine.  

Let us assume you have been provided

with the information you requested in point (ii). You will now employ a

molecular biology technique to create a concentrated solution of the molecule

of interest. 

The image shows a cricketer preparing to

play a shot just as the ball approaches. Which of the following best represents

the sudden electrical response in a neuron that mirrors the cricketer’s swift

reaction to the stimulus (incoming ball)?