Question 1

Which of the following best explains the significance of complementary base pairing during DNA replication?

Accepted Answer

It ensures that each new DNA strand is an exact copy of the original, preserving genetic information.

Question 2

How does the structure of DNA enable it to perform its role as the hereditary molecule?

Accepted Answer

The double helix structure allows for easy separation and accurate copying during cell division.

Question 3

A DNA coding sequence for a gene is 5'-ATG CCT TAA-3'. The mRNA produced from this sequence will be:

Accepted Answer

$$5'-AUG CCU UAA-3'$$

Question 4

During translation, a codon on the mRNA is read and the correct amino acid is added to the polypeptide chain. The tRNA that delivers the amino acid has an anticodon that is:

Accepted Answer

Complementary to the mRNA codon.

Question 5

In a grassland plant growing in dry soil, water and dissolved ions are most likely to move into the root cells by:

Accepted Answer

Osmosis due to a lower water potential inside the root cells.

Question 6

In a common garden experiment, northern and southern red maple seeds are grown in both Rhode Island and Georgia. Northern plants are taller in both locations. What does this suggest about the trait for height?

Accepted Answer

Height is genetically determined, as northern plants are taller regardless of location.

Question 7

A plant cell is placed in pure water ($$\Psi = 0$$ MPa). If the cell contains many dissolved solutes, what will happen?

Accepted Answer

Water will move into the cell, increasing turgor pressure.

Question 8

A root is tipped sideways, and after a short time the root begins bending downward. The best explanation is:

Accepted Answer

Auxin accumulates on the lower side of the root tip, inhibiting growth on that side.

Question 9

After a person steps into a cold room, skin thermoreceptors send signals to the brain, and the body begins shivering to raise body temperature. In this negative-feedback loop, the effector is:

Accepted Answer

The muscles that produce shivering.

Question 10

In a positive feedback loop, a stimulus (A) triggers release of hormone A, and hormone A increases the stimulus. Which of the following is an example of a positive feedback loop?

Accepted Answer

Blood clotting, where platelets release chemicals that attract more platelets.

Question 11

If a plant is placed in a solution that has a lower solute concentration than the cytoplasm, what will occur?

Accepted Answer

Water will move into the plant cell by osmosis.

Question 12

A plant X reproduces by rapidly spreading underground rhizomes, while Plant Y reproduces by outcrossing flowers and fruits. Which reproductive strategy generally requires less energy per offspring?

Accepted Answer

Plant X, because vegetative reproduction is less costly than sexual reproduction.

Question 13

In a nitrogen root nodule, the tissue appears pink and nitrogen fixation continues even when atmospheric oxygen concentration is high. The best explanation is that:

Accepted Answer

Leghemoglobin protects nitrogenase from oxygen, allowing nitrogen fixation to continue.

Question 14

A grassland plant species rapidly invades a field of plants grown from underground rhizomes after a fire. The most likely explanation is:

Accepted Answer

Vegetative reproduction allows for rapid spread from surviving rhizomes.

Question 15

A plant is exposed to blue light, which triggers phototropism. What is the molecular basis for this response?

Accepted Answer

Blue light activates phototropin, leading to differential auxin distribution.

Question 16

In humans, feeling hungry increases salivation. After eating and feeling full, salivation normally decreases. What type of feedback loop does this describe?

Accepted Answer

Negative feedback loop.

Question 17

If a plant cell has a solute potential of $$\Psi_s = -0.5$$ bars, what will be the resulting water potential ($$\Psi) if $$the pressure potential ($$\Psi_p) is$$ $$+0.3$$ bars?

Accepted Answer

$$\Psi = -0.2$$ bars$

Question 18

A plant is moved from a shaded plot to a sunny plot. Which physiological change is most likely to occur?

Accepted Answer

Stomatal density will decrease to reduce water loss.

General Biology Collaborative Exam Study Guide: Genetics, Plant Biology, and Physiology

Study Guide - Practice Questions

Study Guide - Flashcards