All High School Biology Resources
Example Questions
Example Question #21 : Cell Structures And Organelles
Which of the following cellular organelles is responsible for making a majority of the cell's energy?
Rough endoplasmic reticulum
Nucleus
Lysosomes
Mitochondria
Golgi apparatus
Mitochondria
Mitochondria produces most of the energy of the cell. The nucleus stores genetic information and is the site of transcription. The rough endoplasmic reticulum is the site of translation of proteins that have destinations other than in the cytoplasm. These proteins made in the rough endoplasmic reticulum are subsequently transported to the Golgi apparatus, where they are modified, packaged, and sent to their final destinations. Lysosomes have an acidic environment in which digestive enzymes break down polymers that will eventually be recycled.
Example Question #22 : Cell Structures And Organelles
What is the "powerhouse" of the cell?
Nucleus
Cell membrane
Mitochondria
Cell wall
Ribosome
Mitochondria
The mitochondria is responsible for making the energy for the cell by cellular respiration. It does this by taking the major breakdown products of glucose (pyruvate and NADH) and converting them into ATP by the citric acid cycle and electron transport chain. This is an oxygen-dependent process.
Example Question #23 : Cell Structures And Organelles
The mitochondria are commonly considered the powerhouses of the cell. The energy (ATP) necessary for cell function is created within the mitochondria via the process of oxidative phosphorylation (the electron transport chain). In order for oxidative phosphorylation to be effective, certain proteins must maintain a proton gradient between the two membranes that surround the mitochondria.
Studying the structure of the mitochondria, you will notice that the organelle has two membranes. The outer membrane is smooth, while the inner membrane has numerous inversions and folds. These folds are called cristae. What is the purpose of the cristae?
They serve as the location where proteins involved in glycolysis reside
The cristae provide greater surface area for the inner mitochondrial membrane, allowing more electron transport proteins in the organelle and more energy to be produced
The folds are a byproduct of the highly acidic environment caused by the proton gradient. They exist to prevent the proton gradient from damaging the outer mitochondrial membrane.
No known function exists for the cristae.
The cristae serve to funnel protons deeper into the organelle, aiding in oxidative phosphorylation
The cristae provide greater surface area for the inner mitochondrial membrane, allowing more electron transport proteins in the organelle and more energy to be produced
The cristae increase the surface area available within the cell. In order for oxidative phosphorylation of occur, certain proteins must be embedded in the inner mitochondrial membrane. The fold in the membrane allow for a larger surface area, which in turn allows more of these proteins to be embedded. More proteins to create energy means more energy (ATP) for the cell.
Example Question #1 : Understanding Ribosomes
Where are ribosomes synthesized in the cell?
Mitochondria
Cytoplasm
Rough endoplasmic reticulum
Nucleolus
Nucleolus
Ribosomal subunits and rRNA are both created in the nucleolus in order to create functional ribosomes. The nucleolus is a specialized structure for ribosome production and is found within the nucleus.
Mitochondria are responsible for generating cellular energy. The rough endoplasmic reticulum helps modify proteins. The cytoplasm is the aqueous matrix found within the cell.
Example Question #92 : High School Biology
Which of the following is a function of ribosomes?
Breaking down toxic substances that are in the cell
Transporting materials in and out, as well as within the cell
Containing the DNA of an organism
Making new proteins
Making new proteins
Ribosomes are composed of ribosomal RNA (rRNA) and proteins. Their primary function is to bind mRNA and tRNA to build proteins. Ribosomes are the fundamental structure necessary for translation and protein formation.
The nucleus houses the DNA of the cell, the cytoskeleton and specialized proteins transport compounds within the cell, and the smooth endoplasmic reticulum breaks down toxic substances, such as alcohol.
Example Question #2 : Understanding Ribosomes
Which organelle is most involved in the formation of bonds between amino acids?
Ribosomes
Lysosomes
Nucleus
Centrioles
Cell membrane
Ribosomes
Ribosome are structures in the cell where the assembly of polypeptide chains takes place by joining together individual amino acids.
The process of making a protein starts when DNA is transcribed to mRNA in the nucleus. After some modification, the mRNA exits the nucleus and enters the cytoplasm of the cell.
In the cytoplasm, the small ribosomal subunit binds to mRNA at the start codon. tRNA (which is attached to an individual amino acid) and the large ribosomal subunit join as well, to complete the complex. tRNA translocates from the A-site to the P-site, and a new tRNA binds to the A-site. A peptide bond forms between the two amino acids bound to the tRNA molecules in the A and P sites of the ribosome. A new tRNA then enters the A-site, pushing the previous tRNA molecules to the P-site and E-site respectively and the process continues to elongate the peptide chain. This continues until the stop codon is encountered.
None of the other cell structures are involved in the formation of proteins. The nucleus stores genetic information, the cell membrane separates the interior of the cell from its environment, lysosomes degrade waste in the cell, and centrioles organize the mitotic spindle fibers.
Example Question #23 : Common Cell Structures
Which of the following cell structures is composed of proteins and RNA, and serves as the apparatus on which proteins are synthesized?
Golgi apparatus
Smooth endoplasmic reticulum
Mitochondria
Ribosomes
Lysosomes
Ribosomes
A ribosome is an organelle consisting of two subunits, each composed of ribosomal RNA and protein. Ribsomes are the site of protein systhesis, or translation.
Mitochondria produce energy by aerobic metabolism. Lysosomes contain intracellular digestive enzymes. The major function of lysosomes is to digest old or damaged macromolecules, especially proteins. The smooth endoplasmic reticulum is a series of interconnected channels in the cytoplasm that synthesize lipids and remove cellular toxins. The Golgi apparatus modifies and packages protein and lipids according to their destinations.
Example Question #1 : Understanding Ribosomes
Why do scientists posit that mitochondria existed as aerobic bacteria a long time ago?
Mitochondria contain ribosomes that closely resemble the ribosomes of bacteria
Mitochondria cannot interact with the rest of the cell and are treated as foreign objects in the body
Mitochondria do not have their own DNA and must consume other organelles in order to produce DNA
Mitochondria are not classified as an organelle
Mitochondria are a type of bacteria
Mitochondria contain ribosomes that closely resemble the ribosomes of bacteria
Endosymbiosis is a theory widely supported by cell biologists, which states that the mitochondria of eukaryotes very likely evolved from aerobic bacteria living within a host cell. There are three pieces of evidence for this:
1) Mitochondria can only arise from existing mitochondria via a replication mechanisms similar to binary fission.
2) Mitochondria have their own genomes, which more closely resemble the genomes of bacteria than those of eukaryotes.
3) The protein manufacturing machinery (ribosomes) of mitochondria more closely resemble the machinery of bacteria than those found in the cytoplasm of eukaryotes.
Example Question #6 : Understanding Ribosomes
Which of the following is not characteristic found within a fully functional ribosome?
N and C terminus
RNA
Sugar-phosphate backbone
Amino acids
Peptidyl site
Sugar-phosphate backbone
A sugar phosphate backbone is characteristic of a DNA sequence. While fully functional ribosomes are composed of a mix of functional RNA and protein the sugar-phosphate components within the RNA do not comprise the backbone of the entire ribosome. This question also requires the knowledge that an amino acid chain has an N and C terminus. Last, it is important to note that the Peptidyl site is where the bond between two amino acids is synthesized.
Example Question #21 : Cell Structures And Organelles
All of the following are true of ribosomes except __________.
All ribosomes are found in the nucleus
They combine with messenger RNA to make proteins
They are made up of two parts called subunits
They synthesize proteins
All ribosomes are found in the nucleus
Ribosomes synthesize proteins and are made up of two parts called subunits that come together during the process of translation with messenger RNA (mRNA). Ribosomes are not found in the nucleus. They are found floating freely in the cytoplasm or bound to rough ER.
Certified Tutor
Certified Tutor