AP Biology : Cell Structures

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #651 : Cellular Biology

A smooth endoplasmic reticulum is involved in all of the following activities except which one? 

Possible Answers:

manufacturing hormones

breaking down toxins

breaking down toxic cellular by-products

manufacturing lipids

assembling amino acids to make proteins

Correct answer:

assembling amino acids to make proteins

Explanation:

This is because ribosomes assemble amino acids into proteins. Such activity would be found associated with rough endoplasmic reticulum and not the smooth ER. The smooth ER is majorly responsible for breaking down toxins and manufacturing things such as lipids and hormones.

Example Question #652 : Cellular Biology

What are processes in respiration are lysosomes involved in?

Possible Answers:

the degradation of cellular substances

the production of fats

the production of proteins

the production of ATP

the production of polysaccharides

Correct answer:

the degradation of cellular substances

Explanation:

Lysosomes are largely involved in breaking things down, because they contain acid hydrolase enzymes that break down waste materials and cellular debris. They can be described as the stomach of the cell. Lysosomes do not produce these other things. Things like ribosomes, Golgi apparatus, and the mitochondria are involved in these other processes.

Example Question #653 : Cellular Biology

Which of the following is a correct description of an organelle's function?

Possible Answers:

Mitochondria is the location of respiration and the exchange of gases. 

The smooth ER contains metobolic enzymes for digestion of food. 

Chloroplast is the location of photosynthesis, and the process that turns light energy into chemical energy.

Nucleolus is the site of mRNA production for protein synthesis. 

Perixisome produces lipids and gets rid of toxins

Correct answer:

Chloroplast is the location of photosynthesis, and the process that turns light energy into chemical energy.

Explanation:

Chloroplast is the location of photosynthesis, which is the conversion of sunlight energy into chemical energy (in form of chemical bonds). Mitochondria is the site of cellular respiration which is the conversion of chemical energy into ATP. Respiration, or otherwise known as breathing, occurs in the respiratory system. Lysosomes or peroxisomes contain digestive enzyme not the Smooth ER. The Smooth ER is responsible for breaking down of toxins and creation of lipids. The nucleolus is the site of rRNA production for the synthesis of ribosomes which make proteins. 

Example Question #654 : Cellular Biology

The shape of an animal cell is determined by which of the following?

Possible Answers:

Plasma membrane

None of these answers

Cytoskeleton

Cholesterol

Cell wall

Correct answer:

Cytoskeleton

Explanation:

The cytoskeletion determines cell shape. The cytoskeleton consists of three different types of filamentous proteins: microfilaments, intermediate filaments, and microtubules. Elements of the cytoskeleton can interact with the cell membrane and cell junctions to alter the cell's overall structure.

There are no cell walls in animal cells, although the cell wall does play a large part in determining cell shape in organisms that possess them (plants, bacteria, fungi).

Example Question #661 : Cellular Biology

Which organelle works to synthesize an unstable form of energy?

Possible Answers:

None of the other answer choices is correct.

Two of the other answer choices are correct.

Rough endoplasmic reticulum

Chloroplast

Mitochondria

Correct answer:

Two of the other answer choices are correct.

Explanation:

The unstable form of energy that is syntheisized refers to ATP. ATP is an unstable; its three phosphate groups are all negatively charged and repel one another. Remember that BOTH the mitochondria and chloroplast participate in ATP synthesis via chemiosmosis; however, only the chloroplast participates in glucose synthesis via photosynthesis. Note that glucose is a stable form of energy and is not readily usable until it is broken down in the process known as glycolysis.

Example Question #2 : Understanding Specialized Cell Structures

The nucleolus __________.

Possible Answers:

is found in prokaryotes and eukaryotes

is a part of the nucleus responsible for assembling ribosomes

contains all the DNA of the cell

is only found in prokaryotes

None of the other answer choices is true.

Correct answer:

is a part of the nucleus responsible for assembling ribosomes

Explanation:

The nucleolus is a subdivision of the nucleus; thus, it is only found in eukaryotes. It is the site of ribosome assembly. The nucleolus is made of RNA and proteins.

Example Question #662 : Cellular Biology

Histones __________.

Possible Answers:

are only found in eukaryotic cells

All of the answer choices are true.

play a role in gene regulation

are protiens around which DNA coils

are only found in the nucleus

Correct answer:

All of the answer choices are true.

Explanation:

Histones are proteins found in the nucleus of eukaryotic cells. DNA wraps itself around histones to further condense. Also, depending on how tightly the DNA is wrapped around the histones, it may or may not be availible for activity (e.g. replication or transcription). Cells modify the interaction between DNA and histones around certain genes under certain conditions to make those genes available or unavailable as needed.

Example Question #663 : Cellular Biology

In which of the following organisms are vacuoles not usually found?

Possible Answers:

Mammals

Fungi

Plants

Bacteria

Correct answer:

Mammals

Explanation:

Vacuoles are membrane-bound structures that are found in bacterial, plant, fungal, and occasionally, animal cells. Vacuoles function in storage of water and waste and in maintenance of turgor pressure in plants. 

Example Question #213 : High School Biology

In which cellular compartment does glycolysis take place?

Possible Answers:

Cytoplasm (Cytosol)

Intermembrane space

Mitochondrial matrix

Inner mitochondrial membrane

Golgi apparatus

Correct answer:

Cytoplasm (Cytosol)

Explanation:

Glycolysis (the process of breaking down glucose) takes place in the cytoplasm, or cytosol—the aqueous portion of the cytoplasm. It is in the cytoplasm where the enzymes required for glycolysis are found.

The citric acid cycle takes place in the mitochondrial matrix, and the electron transport chain takes place along the inner mitochondrial membrane in order to pump protons into the intermembrane space.

Example Question #214 : High School Biology

What is the function of a kinase?

Possible Answers:

Change the structure of the ligand

Add ubiquitin to the ligand

Add phosphates to ligands

Remove phosphates from ligands

Correct answer:

Add phosphates to ligands

Explanation:

The addition and removal of phosphate groups can serve critical functions in the regulation of protein activity. The binding or uncoupling of phosphate groups frequently serves to activate or deactivate proteins.

A kinase is an enzyme that phosphorylates—or adds a phosphate group to—its ligand.

A phosphatase removes a phosphate group from its ligand.

Several different types of proteins can change the structure of a ligand, such as isomerases, and ubiquitin ligases add ubiquitin to their ligands.

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