AP Biology : AP Biology

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #135 : Cell Structures

Which of the following are true regarding animal cells?

Possible Answers:

They have many small vacuoles

They have cell walls

The have chloroplasts

The have a fixed cell shape

Correct answer:

They have many small vacuoles

Explanation:

Some of the main differences between plant and animal cells are the presence of a cell wall in plant cells, which maintains a regular and rigid cell shape, and chloroplasts, which are the sites of photosynthesis in plant cells. By contrast, animal cells do not have a cell wall, allowing their cell shape to be more irregular and more dependent on cytoskeletal filaments. Animal cells do not perform photosynthesis and therefore do not have chloroplasts. Some, not all, animal cells contain many small vacuoles. 

Example Question #2111 : Ap Biology

Which of the following are true of centrioles?

Possible Answers:

They are found in most plant cells

They play a role in the organization of the mitotic spindle during mitosis

They do not replicate during mitosis

They play a role in transcription

Correct answer:

They play a role in the organization of the mitotic spindle during mitosis

Explanation:

A centriole is a cylindrical structure present in pairs in most eukaryotic cells. They are composed of microtubules arranged in nine triplets and play a role in mitosis and meiosis. During these processes, the centrioles are replicated and each pair migrates to a cell pole. From the centrioles, mitotic spindles emanate to attach to the centromeres of sister chromatids located at the metaphase plate. 

Example Question #137 : Cell Structures

Which organelle has a cis and a trans face?

Possible Answers:

Endoplasmic reticulum

Mitochondria

Golgi apparatus

Nucleus

Correct answer:

Golgi apparatus

Explanation:

The Golgi apparatus is composed of compartments that are organized into a cis and a trans face. The cis face receives proteins from vesicles originating from the endoplasmic reticulum. After fusing with the Golgi apparatus, the proteins are modified and move through the folds, or cisternae, of the Golgi to the trans face. At the trans face, the modified proteins are organized and transported by vesicles from the Golgi apparatus to their final destinations.

Example Question #138 : Cell Structures

Where are ribosomes assembled?

Possible Answers:

Endoplasmic reticulum

Cytoplasm

Golgi apparatus

Nucleolus

Correct answer:

Nucleolus

Explanation:

Ribosomes, the sites of protein synthesis, are found through the cytoplasm, and in eukaryotes, on the endoplasmic reticulum. Ribosomes are assembled in the nucleolus, where rRNA (ribosomal RNA) is transcribed. Ribosomes are made of rRNA and protein, so the ribosomal proteins are synthesized on the rough endoplasmic reticulum, and are transported into the nucleolus to be assembled into ribosomes.

Example Question #23 : Understand Functions Of Organelles In The Cell

A researcher is examining a portion of an endoplasmic reticulum (ER) under an electroscope and finds that the surface lacks ribosomes. What type of ER is the researcher examining?

Possible Answers:

More than one of these

Bacterial ER

Smooth ER

Rough ER

Correct answer:

Smooth ER

Explanation:

Smooth ER lacks ribosomes and functions in diverse metabolic process such as synthesis of lipids, metabolism of carbohydrates, and detoxification of drugs and poisons. Rough ER contains ribosomes on its surface and functions in protein synthesis. Bacteria lack endoplasmic reticulum since it is membrane-bound.

Example Question #2111 : Ap Biology

DNA can be found in which of the following cellular compartments of a eukaryotic cell?

Possible Answers:

Nucleus, mitochondria, chloroplasts and cytoplasm

Nucleus, mitochondria, and chloroplasts

Nucleus and mitochondria only

Nucleus only

Correct answer:

Nucleus, mitochondria, and chloroplasts

Explanation:

While most of a cell's DNA is located in the nucleus, some DNA is found in the mitochondria and chloroplasts. The DNA found in plasmids supports the endosymbiotic theory. The cytoplasm of eukaryotes does not contain free floating DNA like in prokaryotes.

Example Question #2112 : Ap Biology

What are extranuclear genes and what are their functions?

Possible Answers:

Extranuclear genes are genes located outside the nucleus that aid in DNA replication and protein synthesis

Extranuclear genes are additional genes within the nucleus that play a role in DNA replication and protein synthesis

None of these

Extranuclear genes are additional genes within the nucleus that do not play a significant role within the cell 

Extranuclear genes are genes located outside the nucleus that do not play a significant role within the cell 

Correct answer:

Extranuclear genes are genes located outside the nucleus that aid in DNA replication and protein synthesis

Explanation:

Extranuclear genes, also known as cytoplasmic genes, are genes located outside the nucleus. They can be found in other parts of the cell, such as the mitochondrion, chloroplasts, and other plastids. Each of these organelles is thought to have originally been an independent prokaryotic cell, ingested by another cell, known as the endosymbiotic theory. Each of these organelles has its own DNA and works in cooperation within the nuclear DNA. 

Example Question #2113 : Ap Biology

Which of the following statements is true?

Possible Answers:

The Golgi apparatus synthesizes lipids and metabolizes carbohydrates ingested by the cell

Peroxisomes are composed of enzymes that create hydrogen peroxide, which is then converted to water 

The smooth endoplasmic reticulum synthesizes proteins

Ribosomes house chromosomes and synthesize DNA

The mitochondrion is responsible for breaking down damaged organelles and ingested substances

Correct answer:

Peroxisomes are composed of enzymes that create hydrogen peroxide, which is then converted to water 

Explanation:

Ribosomes are organelles composed of two subunits of ribosomal RNA and proteins. There are two types: free ribosomes, which are found in the cytosol of the cell, and bound ribosomes, which are bound to the rough endoplasmic reticulum. Their primary purpose is to synthesize proteins. Messenger RNA will bring amino acids to the ribosomes, where proteins are then synthesized. The endoplasmic reticulum is an organelle that is composed of bounded tubules and sacs and is continuous with the nuclear envelope. It is composed of two parts: the smooth endoplasmic reticulum and the rough endoplasmic reticulum. The smooth endoplasmic reticulum synthesizes lipids, metabolizes carbohydrates, stores calcium, and detoxifies the cell of drugs and poisons. The rough endoplasmic reticulum, studded with ribosomes, aids in protein synthesis. The mitochondrion is bound by a double membrane; the inner membrane has many infoldings called cristae. This increases the surface area of the organelle and therefore increases productivity. Known as the “powerhouse of the cell,” the mitochondrion creates ATP for the cell through a process known as cellular respiration. Peroxisomes are specialized metabolic organelles bound by a single membrane. They contain enzymes that transfer hydrogen atoms from substrates to oxygen, producing hydrogen peroxide. Hydrogen peroxide is then converted to water. The Golgi apparatus is a stack of flattened membranous sacs. Its purpose is to modify proteins, carbohydrates, and phospholipids. Polysaccharides are also synthesized here. Besides synthesis and modification of these macromolecules, the Golgi apparatus also sorts products and sends them to other parts of the cell through vesicles. 

Example Question #2114 : Ap Biology

In the study of cell biology, organelles can be examined using __________.

Possible Answers:

the naked eye

a light microscope

a magnifying glass

an electron microscope

Correct answer:

an electron microscope

Explanation:

Organelles, for the most part, are too small to be clearly defined by a simple light microscope. Although, larger organelles may be seen with a light microscope, they cannot be well-studied using them. An electron microscope can achieve remarkable magnification and resolution. Some electron microscopes can even resolve individual molecules or atoms. Also note that an egg (chicken, human, ostrich etc.) is a single cell. We can study the nucleus (yolk) with the naked eye, but this is a special case, and the question does not provide us any information that would make this a reasonable assumption.

Example Question #2115 : Ap Biology

What is the process by which a cell intakes extracellular fluid in "gulps" via tiny vesicles?

Possible Answers:

Pinocytosis

Phagocytosis

Exocytosis

Simple diffusion

Correct answer:

Pinocytosis

Explanation:

Pinocytosis is the uptake of extracellular fluids. The cell accomplishes this by creating vesicles from the cell membrane around droplets of extracellular fluid and carrying them inside the cell. This process is unspecific in which substances it carries into the cell (not receptor-mediated). Exocytosis involves the same concept, but in the other direction (from inside the cell out). Simple diffusion does not involve the creation of vesicles, rather it involves substances freely diffusing through the plasma membrane from areas of high concentration to areas of low concentration without the net input of energy.    

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