GRE Subject Test: Biology : GRE Subject Test: Biology

Study concepts, example questions & explanations for GRE Subject Test: Biology

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Example Questions

Example Question #2 : Understand Inputs And Outputs, Purpose

Some organisms, such as green plants, are capable of obtaining energy directly from photosynthesis. These organisms are termed __________.

Possible Answers:

herbivores

autotrophs

homotrophs

heterotrophs

primary consumers

Correct answer:

autotrophs

Explanation:

Autotrophs are organisms that produce complex organic compounds from substances present in the surroundings. These organisms may do this through the use of energy from light or from inorganic chemical reactions.

In contrast, heterotrophs require organic input in order to generate biological compounds and are unable to use light or inorganic materials for energy.

Example Question #351 : Gre Subject Test: Biology

Which of the following refers to the principle of alternation of generations in plants?

Possible Answers:

Gamete-producing sporophytes

The differences between a tree and a seed

A life cycle that includes a multicellular haploid stage

The need for external pollinators

A life cycle which includes a unicellular haploid stage

Correct answer:

A life cycle that includes a multicellular haploid stage

Explanation:

Plants have a multicellular haploid stage called the gametophyte. Gametophytes () produce gametes () through mitosis, which combine to produce a zygote (). The zygote grows into a multicellular, diploid sporophyte (), which produces spores () through meiosis. Those spores give rise to multicellular gametophytes.

Example Question #1 : Understanding Vascular And Avascular Plants

Fill in the blanks.

The __________ generation is dominant in the bryophyte life cycles, and the __________ generation is dominant in seedless vascular plants.

Possible Answers:

gametophyte . . . gametophyte

gametophyte . . . sporophyte

sporophyte . . . gametophyte

sporophyte . . . sporophyte

Correct answer:

gametophyte . . . sporophyte

Explanation:

Bryophytes are nonvascular plants, such as mosses. Gametophytes are species that have haploid cells during their mature lives, while sporophytes are predominantly diploid during their adult phases.

Bryophytes have the gametophyte generation as dominant, with the sporophytes relying on the parental gametophyte. Starting with the evolution of seedless vascular plants, the gametophytes become reduced and are no longer the dominant life cycle. By the formation of angiosperms (seed plants), the gametophytes have become dependent on the parental sporophyte. 

Example Question #1 : Classes Of Plant

Which of the following structures would be found in a tracheophyte, but not in a bryophyte?

Possible Answers:

Chloroplasts

Xylem

Plasmids

Cell walls

Correct answer:

Xylem

Explanation:

All plants can be classified as either bryophytes or tracheophytes. Plants that contain transport vessels (xylem and phloem) are tracheophytes, while those without transport vessels are bryophytes. All plants contain cell walls and chloroplasts, but only a tracheophyte would contain xylem. Plasmids are structures that are almost exclusively found in bacteria or protozoans.

Example Question #2 : Evolution

Which of the following is false of the phylum chordata?

Possible Answers:

They are protostomes

They have a notochord at some point in their development

They have a coelom

They have bilateral symmetry

Correct answer:

They are protostomes

Explanation:

All chordates are deuterostomes, not protostomes. During early development, the formation of the blastopore leads to the growth of the digestive tract. In protostomes, the blastopore develops into the mouth, while in deuterostomes it becomes the anus.

All chordates have a notochord during development, which eventually gives rise to the nervous system. Chordates also have a coelom, or fluid filled cavity, somewhere within the body and they all exhibit bilateral symmetry.

Example Question #1 : Evolution

Which of the following is not necessary for designation as a chordate?

I.  A notochord

II.  Vertebrae

III.  A post-anal tail

IV.  Gill arches 

V.  A dorsal, tubular nervous system

Possible Answers:

I

V

II

III

IV

Correct answer:

II

Explanation:

Chordates must have, at some point in their embryogenesis, all features except vertebrae. Although the vast majority of chordates are vertebrates, Amphioxus has only a notochord. This primitive organism never develops vertebrae. Man has gill arches, and remnants of these are seen in certain congenital malformations. The notochordal remnants can give rise to the tumor known as a chordoma. The brain has ventricles (it is tubular) and it is certainly dorsal. Finally, human tail persists in about one per million live births.  

Example Question #1 : Evolution

Which of the following statements about chordates is true?

Possible Answers:

They are protostomes

All chordates are vertebrates

They lack a coelom 

Their anus forms from the blastopore

Correct answer:

Their anus forms from the blastopore

Explanation:

The phylum chordata has a few key characteristics. They are deuterostomes, meaning that the anus arises from the blastopore. They have a coelom that arises from the mesoderm during development, and at some point they have a tail, pharyngeal slits, and a notochord.

Vertebrata is a subphylum of chordata, so not all chordates are vertebrates (though all vertebrates are chordates).

Example Question #1 : Animalia

Which of the following organelles is/are mainly present in animal cells?

I. Peroxisome

II. Centrioles

III. Flagella

Possible Answers:

II and III

III only

I and III

I only

II only

Correct answer:

II only

Explanation:

Centrioles are generally only found in animal cells, but have been found in a variety of eukaryotes. There are a small subset of plants that do contain centrioles. Some plant cells have flagella and peroxisomes.

Example Question #352 : Gre Subject Test: Biology

Which of the following would be a secondary consumer?

Possible Answers:

People who are keen to eat bear, which eats small mammals that live off berries and seeds

Earthworms, bacteria and fungi that decompose plant matter on the forest floor to replenish the soil

A black-tailed deer that browses on grasses and shrubs

A western diamondback rattlesnake that preys on field mice that eat seeds and berries

A maple tree that stores energy harnessed from the sun in the form of sugars through a process called photosynthesis

Correct answer:

A western diamondback rattlesnake that preys on field mice that eat seeds and berries

Explanation:

A secondary consumer is a step above the primary consumer (herbivore) on the food chain, consisting of omnivores and carnivores. A mouse that lives off plant matter and is thus a primary consumer. When a snake eats the mouse, it is the secondary consumer in the food web.

Example Question #353 : Gre Subject Test: Biology

What is the ratio of energy generated by producers to the energy absorbed by the next trophic level up, that of primary consumers?

Possible Answers:

Correct answer:

Explanation:

With every advancement in the trophic level, energy converts on a ten-to-one scale. For example, ten kilograms of grain fed to a steer produces roughly one kilogram of beef. This is true for every step up the tropic food pyramid.

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