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Which statement explains the effect of an inhibitor on an enzyme?
A substrate will be able to bond with the enzyme.
The enzyme will likely be attacked by immune cells.
The enzyme will be unable to produce more enzymes.
A substrate will be unable to attach to the enzyme.
Four different nucleotides are used as building blocks of DNA. Which of the following can be used to distinguish one nucleotide from another?
The nitrogenous base
The shape of the deoxyribose sugar
The length of the phosphate group
The type of fatty acid
In the 1940s scientists performed an experiment that ultimately identified the site of protein synthesis. They also identified the molecule responsible for transporting information from the nucleus to the site of protein synthesis. What was this newly identified molecule?
Which statement best describes the relationship between the products of photosynthesis and the reactants in cellular respiration?
The products of photosynthesis serve as the reactants in cellular respiration to provide chemical energy.
The products of photosynthesis combine with the reactants in cellular respiration to remove ATP from cells.
The products of photosynthesis inhibit the reactants in cellular respiration in the presence of light.
The products of photosynthesis change the structure of the reactants in cellular respiration in the presence of light.
Which process and product are represented in Diagram 2?
Process: transcription; product: mRNA
Process: translation; product: protein
Process: replication; product: tRNA
Process: recombination; product: polymerase
A student is looking for evidence that spindle fibers are separating the chromosomes to ensure that each new nucleus has one copy of each chromosome. Which diagram is the student looking for?
Nitrogenous bases are located on both strands of the DNA double helix. What is the significance of the nitrogenous bases?
The number of adenines and cytosines determines the type of RNA that will be produced.
The order of nitrogenous bases determines the order of amino acids in the proteins synthesized.
The amount of thymine and guanine in the DNA molecules determines the length of the genes.
The type of hydrogen bonding between the nitrogenous bases determines which amino acid will be added to the peptide chain.
Which two processes does this diagram most directly model?
Energy conversions and synthesis of new molecules
Synthesis of new molecules and homeostasis
Transport of molecules and energy conversions
Homeostasis and transport of molecules
Cells pass through a G2 checkpoint before entering mitosis. Ideally, if DNA damage is detected, the cells do not enter mitosis until the damage is repaired. Why is DNA damage repaired before cells enter mitosis?
So that another round of DNA synthesis does not have to take place
So that the chromosomes can align at the metaphase plate during mitosis
So that the cytoplasm can be divided equally between the two daughter cells
So that healthy daughter cells are produced, allowing the organism to continue growing
In all three complex carbohydrates, the subunits of glucose are bonded together differently. Because they have different structures, they most likely —
contain different chemical elements
form different proteins
carry different nucleotides
perform different functions
The photograph shows a laboratory investigator examining samples of DNA in a procedure called PCR, or polymerase chain reaction. Using PCR, the investigator can create thousands or even millions of copies of a fragment of DNA for closer investigation. In which of these situations would PCR be most useful?
When only a small amount of DNA is available, such as at a crime scene
When the DNA of identical twins is being mapped
When the genome of a population is being analyzed for preventable diseases
When the blood type of a DNA donor is known
Oncogenes are mutated forms of genes. Oncogenes can transform a cell into a tumor cell. Some tumor cells are benign, while others are malignant. How does the presence of an oncogene lead to the formation of a tumor?
ATP production is inhibited.
Cell division is unregulated.
Somatic cell growth is inhibited.
Antibody activity is unregulated.
Each strand of a DNA molecule contains nitrogenous bases that pair with other nitrogenous bases in very specific ways. A diagram of a section of DNA is shown. Which DNA strand is complementary to the one shown above?
AGU GCU GCG CGU A
TGT AGC TGC GCG T
ACA TCG ACG CGC A
TCG CGC AGC TAC A
A single-celled organism can be classified as a prokaryote based on the absence of —
a cell membrane
Which statement describes the mutation in the diagram?
A silent mutation results in the insertion of a different amino acid.
A substitution occurs with the adenine base.
A deletion of cytosine base occurs
A base inserted into one strand of the DNA
This part of the cell cycle is best described as the process that —
duplicates the DNA
completes cell division
maintains genetic homeostasis
synthesizes new molecules
Which statement about enzyme activity is best supported by this graph?
An enzyme must be composed of multiple polypeptides, or subunits, to be active.
An enzyme’s rate of activity increases with time until it becomes inactive.
An enzyme functions best under specific temperature conditions.
An enzyme works equally well in bacteria that are adapted to high temperatures and in eukaryotic cells such as human cells.
Which table correctly identifies the four most-abundant elements in biomolecules?
Which molecule synthesized by plants is a major source of energy for cellular processes in both plants and animals?
Which of these is the direct result of an error in the transcription of a DNA nucleotide?
the nuclear membrane is ruptured
amino acids do not bond to tRNA
a codon sequence is incorrect
transportation of mRNA does not occur
What is the purpose of this process this process?
To replicate the DNA of an organism before cell division
To assemble nucleotides in an mRNA chain along a DNA template
To synthesize amino acids used to unzip strands of DNA and copy the genetic code
To translate the genetic code into a specific sequence of amino acids
Photosynthesis and cellular respiration both involve the use and release of gases. Which statement correctly identifies the role of gases in the two processes?
Photosynthesis and cellular respiration both use carbon dioxide and release oxygen.
Photosynthesis and cellular respiration both use oxygen and release carbon dioxide.
Cellular respiration uses oxygen and releases carbon dioxide, while photosynthesis uses carbon dioxide and releases oxygen.
Cellular respiration uses carbon dioxide and releases oxygen, while photosynthesis uses oxygen and releases carbon dioxide.
Which statement describes this model of DNA?
The model is inaccurate because the base pairs are incorrect.
The model is accurate because it contains correctly paired bases.
The model is accurate because it shows each base splitting to form a double helix.
The model is inaccurate because some typical bases in
DNA are missing.