Previous Test questions Flashcards
What biological molecule do viroids and retroviruses use store and transmit genetic information?
RNA
DNA contains the purines _________, while RNA contains the pyrimidines _________.
Adenine and guanine / cytosine and uracil
_______________ are the nitrogenous bases found in DNA, whereas ________________ are the nitrogenous bases found in RNA.
adenine, cytosine, guanine, thymine / adenine, cytosine, guanine, uracil
You recently isolated a double-stranded DNA molecule with 1000 purines and 1000 pyrimidines. This molecule could consist of precisely -
1000 guanine and 1000 cytosine nucleotides
What property of the DNA molecule allows cells to recognize DNA damage and repair this damage?
The ability of complementary base pairs to interact by forming hydrogen bonds
Which bases form the hydrogen bonds that enable the two strands of the double helix to bind to one another so effectively
Adenine forms 2 bonds with thymine, and guanine forms 3 bonds with cytosine
What is a false statement about lipids?
c) Some of our hormones are triacylglycerols (triglycerides)
Some of our hormones are triacylglycerols (triglycerides)
In all single-cell species and multi-cell species, which molecule stores the exact sequence of amino acids in every protein and the exact sequence of nucleotides in every specialized RNA molecule?
DNA
What is the unique function of polynucleotides?
The storage and transmission of genetic information
What is not an example of an essential function of RNA?
The storage of excess food energy
What type of biological molecule generally must fold into a specific, complex 3-Dimensional structure after it is made in order to become biologically-active?
Protein
Fever is induced in response to the detection of some pathogens (disease-causing agents). How could the fever response possibly deactivate some of the disease-causing proteins that pathogens produce?
They could be denatured
What is a direct result of improper protein folding?
Mad Cow Disease
Where is DNA localized within most human cell types?
Nuclei and mitochondria
Specific protein/DNA interactions are essential for life to occur. The surface of a protein that binds directly to DNA might exhibit which characteristic?
Positive electrical charge
We discussed the relationship between the size of a carbohydrate and its function. Which carbohydrate would not be a good candidate to be distributed to all of the cells in the body of a large organism?
Glycogen
Which carbohydrate stored in our muscle cells and liver cells would decline in concentration after we participated in three hours of demanding physical activity?
Glycogen
We discussed the relationship between the size of a carbohydrate and its function. Which statement regarding monosaccharides is true?
They can be imported into cells and exported from cells
We discussed the relationship between the size of a carbohydrate and its function. What is a true statement regarding polysaccharides?
Chitin is used to provide structural support in many animal species
A mutant plant recently was identified that is extremely short due to a lack structural support. Which carbohydrate probably is affected in this mutant plant?
Cellulose
Why do so many cultures include specific types of plant foods with every meal?
This practice provides a complete set of essential amino acids
Which biological molecule, when it is improperly folded, has been linked to some neurodegenerative disorders?
Protein
What generally is not a primary function of proteins?
Waterproofing surfaces
Why does the structure of a protein largely determine its function?
Structure determines the ability to interact with other molecules
Which group of monomers do our cells use to form polypeptides?
Amino Acids
How does the hydrophobic effect relate to the assembly of some biological structures?
It allows some types of molecules to form the lipid bilayer
Which specific type of biological molecules interact with one another, in the presence of water, to form a lipid bilayer?
Phospholipids
What is a true statement regarding lipids?
Lipids generally have a uniform electrical charge distribution that prevents them from interacting with hydrophilic water molecules
Which specific biological molecule is specialized to store excess food energy effectively?
Triglyceride
A malnourished child that lacks the substrates (molecular building blocks) to synthesize some lipids could have a diet insufficient in -
Essential fatty acids
Which characteristic makes ribozymes such potentially attractive pharmaceuticals?
Degrading RNA with a specific nucleotide sequence
We discussed how malnutrition can result from the lack of one or more essential nutrients. Which disorder results from the absence of the essential amino acid tryptophan?
Pellagra
We discussed the relationship between the size of a carbohydrate and its function. Which carbohydrate would we expect to find in the human bloodstream?
Glucose
Lipids play many roles in animals and plants. Which function is not performed by lipids in plants?
Catalysis
Which combination of lipids would be expected to occur in cellular membranes?
Phospholipids, steroids
The possibility that surgical equipment could be contaminated with prions is a valid concern among health care professionals. Which treatment would have the highest probability of reducing the activity of prions contaminating the surface of a scalpel?
Treat the surface with an enzyme that degrades proteins
Which type of stem cell is totipotent?
Embryonic (before or at the 8-cell embryo stage)
Among the types of stem cells we discussed, which type should be used to study how a single cell develops into an organism?
Embryonic (before or at the 8-cell stage)
What is a true statement regarding stem cell niches in the human body?
They probably help to maintain adult stem cells in an unspecialized state and respond effectively to Go-Signals
We discussed the types of tissues that interact to form animals and those that interact to form plants. Which type of tissue in animals and which type of tissue in plants cover all surfaces exposed to the environment?
Epithelial and Dermal
We discussed the internal structures that exist within prokaryotic and eukaryotic cells. What is one difference between the internal structures within prokaryotic and eukaryotic cells?
Micro-compartments in prokaryotes are surrounded by a protein shell, whereas the organelles in eukaryotes are surrounded by a membrane
Prions, viroids, and viruses are pathogens (disease-causing agents) that typically are smaller than prokaryotic cells and eukaryotic cells. Why aren’t these pathogens considered the most fundamental units of life?
They cannot obtain and use energy, repair, or reproduce independently
Which specialized, internal structures within eukaryotic cells are specialized to perform specific biochemical functions?
Organelles
The human body regulates the cell cycle with great precision. Why must our bodies regulate the cell cycle with such precision?
- The activity of all 220 cell types must be coordinated to serve the body’s overall needs
- The loss of cell cycle control could result in cancer
- Our adult stem cells must only divide when it serves the overall needs of the body
- A loss of cell cycle control could prevent the proper repair of injured cells and tissues
The human body regulates the cell cycle with great precision. Which mechanism evaluates critical biochemical events at specific points in the cell cycle?
Checkpoints
How will a newly formed cell in the G1 phase respond when it does not recognize a Go-Signal?
This cell will exit the cell cycle and enter the G0 phase
In an adult stem cell, the activation of the G2 checkpoint resulted in the correction of a critical biochemical error. What is the next step for this adult stem cell after correcting this error?
Enter the M Phase
The human body instructs a specific population of adult stem cells to divide when a new supply of cells is required. How do our bodies accomplish this?
Go-Signals and their receptors
Which family of proteins bind to and stimulate the activity of the cyclin-dependent kinases that regulate the transition from one cell cycle phase to the next (G1 to S Phase, for example)?
Cyclins
In order for the human body to grow, develop, repair, and reproduce its trillions of cells must be able to communicate effectively with one another. All of the following are directly involved in cell signaling (cell to cell communication) except for -
DNA Polymerase
The hydrophobic, steroid hormones estrogen and testosterone are Go-Signals for some cell types in the human body. How are these hydrophobic hormones recognized by the proper target cells in the body?
Receptors within the cell
In order to maintain proper cell cycle regulation, the cyclin proteins must be degraded after activating the proper cyclin-dependent kinase. How do our cells degrade the cyclin proteins, and other proteins, in a regulated manner?
Proteasome
An adult stem cell no longer requires a “Go-Signal” to divide. What is one possible cause?
A Tyrosine Kinase Receptor is constantly activated
A population of adult stem cells in a specific stem cell niche responds to a specific “Go Signal”. This “Go-Signal” is a large, hydrophilic protein. Where would the receptor for this “Go-Signal” be localized?
Cell membrane
What is the name of a nucleotide sequence that contains the information to make a specific polypeptide or specialized RNA molecule?
Gene
Which event enables our adult stem cells to pass through the G1 (Gap 1) restriction point checkpoint?
Go-Signal recognition
Which part of an eukaryotic gene determines the amino acid sequence of the polypeptide the gene encodes?
Exon
A cell has a lethal defect that prevents it from making the short, complementary RNA primer molecule that is required for DNA replication to occur. Which component of DNA replication must be defective?
Primase
Which enzyme preserves the integrity of the information stored in the genes located at the ends of our DNA molecules/chromosomes?
Telomerase