AP Biology : Cellular Biology

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #2 : Understand Functions Of Organelles In The Cell

Where would you be least likely to find a transmembrane protein?

Possible Answers:

Cell membrane

Ribosomes

Mitochondria

Nucleus

Chloroplasts

Correct answer:

Ribosomes

Explanation:

The simple answer here is that all of these organelles have a membrane, except for ribosomes. Nuclei, mitochondria, chloroplasts, and cells as a whole have transmembrane proteins spanning the lipid bilayer, which can be used for transport or other purposes. Ribosomes are mostly comprised of rRNA and do not have membranes; thus, they will not bear transmembrane proteins.

Example Question #2 : Understand Functions Of Organelles In The Cell

The Golgi apparatus is responsible for which function of the cell?

Possible Answers:

Protein degradation

Protein packaging

Protein synthesis

Protein storage

Correct answer:

Protein packaging

Explanation:

The Golgi apparatus is a series of flattened membrane sacs found in the cell. It receives vesicles filled with proteins from the rough endoplasmic reticulum. The Golgi apparatus is responsible for recognizing proteins based on their signal sequences and sending concentrations of similar proteins to various parts of the cell. It can also deliver proteins out of the cell using secretory vesicles. The membrane sacs of the Golgi apparatus are constantly used and regenerated to create vesicles of packaged proteins.

Example Question #2 : Understand Functions Of Organelles In The Cell

Which of the following structures/functions is not created using microtubules?

Possible Answers:

Muscle contraction

Eukaryotic flagella

Mitotic spindles

Cilia

Correct answer:

Muscle contraction

Explanation:

Muscle contraction is accomplished using the function of microfilaments, namely actin and myosin. Microtubules are not a key player in muscle contraction, but are used to create the mitotic spindles, flagella, and cilia. Microtubules are a key element of the cytoskeleton, and are generally involved in structural aspects of the cell.

Example Question #3 : Understand Functions Of Organelles In The Cell

Ribosomes are the site of protein synthesis in both eukaryotes and prokaryotes. In eukaryotes, ribosomes can either be "free" or "bound." To which larger organelle are bound ribosomes attached?

Possible Answers:

Lysosomes

Rough endoplasmic reticulum

Golgi apparatus

Mitochondria

Smooth endoplasmic reticulum

Correct answer:

Rough endoplasmic reticulum

Explanation:

While free ribosomes are present independently in the cytosol, bound ribosomes are attached to the rough endoplasmic reticulum. Their presence gives this organelle its "rough" appearance and distinguishes it from the smooth endoplasmic reticulum, which does not contain ribosomes. The nuclear envelope, which surrounds and protects the eukaryotic nucleus, is also the site of some bound ribosomes and is connect to the rough endoplasmic reticulum. The Golgi apparatus, lysosomes, and mitochondria have no ribosomes bound to their membranes.

Example Question #3 : Understand Functions Of Organelles In The Cell

Which of the following organelles directly requires oxygen to maintain optimal function?

Possible Answers:

Ribosomes

Smooth endoplasmic reticulum

Plasmids

Nucleolus

Mitochondria

Correct answer:

Mitochondria

Explanation:

The mitochondria are membrane-bound organelles involved in the process of cellular respiration. Specifically, the Krebs cycle takes place in the matrix of the mitochondria and the electron transport chain takes place along the inner mitochondrial membrane. During aerobic respiration, oxygen is used as the final electron receptor of the electron transport chain and generates water as a byproduct. Without oxygen, the mitochondria cannot perform oxidative phosphorylation, and the cell must rely on glycolysis for energy.

Example Question #2 : Understand Functions Of Organelles In The Cell

Of the following organelles, which contains hydrolytic enzymes that can break down cellular debris?

Possible Answers:

Lysosome

Endoplasmic reticulum

Plasma membrane

Nucleus

Peroxisome

Correct answer:

Lysosome

Explanation:

Lysosomes contain hydrolytic enzymes that can digest macromolecules from phagocytosis, endocytosis, and autophagy. When damage occurs to the membrane of the lysosome, these enzymes can be released and cause damage to the cell, leading to apoptosis.

Peroxisomes contain peroxidases, which help to eliminate hydrogen peroxide from the cell and prevent the creation of free radicals. The nucleus houses DNA and would be severely damaged by the introduction of hydrolytic enzymes. The plasma membrane is used to contain the cytoplasm and organelles and the endoplasmic reticulum is used to modify and package proteins.

Example Question #5 : Understand Functions Of Organelles In The Cell

A centriole is a cylindrical structure that is primarily involved in which process?

Possible Answers:

Cell division

Glycolysis

Lipid storage

Gluconeogenesis

Cellular respiration

Correct answer:

Cell division

Explanation:

Centrioles are cell structures that are mainly composed of tubulin and are involved in the organization of the mitotic spindle and cytokinesis during cell division.

Cellular respiration primarily occurs on the inner mitochondrial membrane with the aid of membrane proteins. Glycolysis and gluconeogenesis occur in the cytoplasm and are facilitated by proteins. Lipids are mostly stored in bones and adipose tissue. These processes do not require intervention from the cytoskeleton or microtubules that compose the centrioles.

Example Question #3 : Understand Functions Of Organelles In The Cell

What cellular structure is composed of a protein skeleton that is made up of lamins?

Possible Answers:

Mitochondrion

Chloroplast

Lysosome

Nucleus

Peroxisome

Correct answer:

Nucleus

Explanation:

Nuclear lamins are fibrous proteins (intermediate filaments) that provide the structural function and the transcriptional regulation in the nucleus of a cell. Note that lamins differ from laminins, which are a protein component of basement membranes.

Example Question #601 : Cellular Biology

What term describes the tendency of an organism to maintain a relatively stable equilibrium between interdependent elements in its internal environment?

Possible Answers:

Mitosis

Synthesis

Homeostasis

Respiration

Reproduction

Correct answer:

Homeostasis

Explanation:

Homeostasis is the mechanism that allows for organisms to maintain equilibrium of their internal environments. Certain variables of the internal environments are regulated such that the conditions of the organism remain stable and relatively constant. This is often accomplished via negative feedback loops and hormone regulation.

Reproduction refers to an organism's ability to generate offspring. Respiration refers to the method of gas exchange in the lungs. Synthesis refers to the generation of certain molecules. Mitosis refers to cellular division. While any of these processes could be used to affect the equilibrium state of an organism, they are all mediated by homeostatic mechanisms in order to maintain biological stability.

Example Question #602 : Cellular Biology

Which of the following is true of mitochondria?

Possible Answers:

All of these are true statements

Mitochondria are involved in energy metabolism

Mitochondria are independent of the endomembrane system

Mitochondria have more than one membrane

Mitochondria contain DNA and ribosomes

Correct answer:

All of these are true statements

Explanation:

Each of these answers correctly describes characteristics of mitochondria. Mitochondria are semi-autonomous: they are capable of synthesizing some of their own proteins with DNA and ribosomes. The proteins are then embedded in the inner mitochondrial membrane, and function in the electron transport chain. Mitochondria have two membranes, an inner membrane and an outer membrane. Mitochondria are the sites of cellular respiration and ATP production, often called the "powerhouse" of the cell. After glycolysis, pyruvate is transported to the mitochondrial matrix for the Krebs cycle and electron transport chain. Mitochondria are not involved in the endomembrane system; they are separate organelles.

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