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WorksheetsBiology Practice STAAR
Total questions: 16
Worksheet time: 17mins
1. Which of the following is evidence that supports the scientific explanation of the endosymbiotic theory?
I
II
III
IV
Telophase is a stage of a cellular process that begins after the chromosomes have moved to opposite poles of the cell. During which cellular process does telophase occur?
Mutations
Mitosis
Interphase
Anaphase
People who have leukemia, a cancer that affects white blood cells, are often given Cytarabine. This drug inhibits the synthesis of DNA. Which phase of the cell cycle is most affected by Cytarabine?
G1
S
G2
Mitosis
Environmental factors typically activate genes in a cell by causing the cell to —
form haploid gamete cells through meiosis
fuse with another cell to increase the size of its genome
produce identical daughter cells through mitosis
transcribe specific DNA segments to mRNA for translation
During the cell cycle, proteins called cyclins bind to enzymes that send signals for the cell to progress through stages of cell replication. At the end of this cycle, the cyclins degrade to prevent further signaling for the cell to divide. Uncontrolled production of cyclins will most likely result in —
the formation of tumors
the immediate death of the cell
the transfer of cyclins to other cells
the formation of haploid cells
A student is going to purchase a vehicle and wants to make sure that the car has a low impact on the environment.
Car A
Car B
Car C
Car D
What is lost to the environment at each of the trophic levels of this ecosystem?
Nutrients from the soil
Food sources
Heat
Living space for the organisms
A student studying primary succession should focus on which of these communities?
Granite rock
Floodplain
Open oak woodland
Mesquite grassland
Saprophytes are fungi that feed on dead and decomposing organisms. They secrete enzymes that digest components of cell walls, such as cellulose and lignin. Which statement explains why these fungi are an important part of the biogeochemical cycle?
Saprophytes perform gas exchange that assists the cellular activities of autotrophs.
Saprophytes transport nutrients through the xylem and phloem in autotrophs
Saprophytes extract minerals from living tissue to recycle them back into the soil.
Saprophytes return organic material to the soil for use by living organisms.
People who have Alzheimer’s disease experience an increasing loss of brain function and cognition over time. Alzheimer’s is characterized by a buildup of abnormal protein fragments that damage brain cells. Recently scientists have discovered an enzyme, BACE2, that decreases these abnormal protein fragments in the brain of a person with Alzheimer’s disease. Which statement explains how BACE2 most likely works?
BACE2 breaks down into smaller pieces that react with the abnormal protein fragments, forming more complex molecules.
BACE2 speeds up the reaction that breaks down the abnormal protein fragments.
BACE2 molecules link several abnormal protein fragments together, forming a complete protein.
BACE2 is a reactant that combines with the abnormal protein fragments.
Which of the following substance stores the most energy?
One gram of fat
One gram of alcohol
One gram of protein
One gram of carbohydrate
If Enzyme B is functioning at 30 oC and a pH of 5, under which conditions would the rate of the enzyme action probably increase?
The temperature is decreased to 25 oC and the pH is kept the same.
The temperature is increased to 35 oC and the pH is increased to 7.
The temperature is increased to 35 oC and the pH is kept the same.
The temperature is kept the same and the pH is lowered to 3.5.
In humans blood type is determined by the A, B, and O alleles. The A and B alleles are codominant to each other and dominant over the O allele. An individual with the AB blood type and an individual with the O blood type can produce offspring with which of the following phenotypes?
O only
A or B only
A, B, or O only
A, B, AB, or O
The diagram above shows the process of meiosis. The segregation that occurs during meiosis results in a —
decrease in the total number of cells per organism
reduction in the number of chromosomes per cell
single fertilized egg cell
group of genetically identical cells
A mutation is least likely to affect a cell when the mutation —
reverses the order of bases in a DNA strand
allows the total number of bases in a DNA sequence to remain the same
replaces a base with its complementary base
produces a triplet that codes for the same amino acid as the original triplet
Transcription is a crucial process to making proteins. Which statement best describes what takes place during transcription?
Instructions from DNA are brought to the ribosome.
mRNA is synthesized from a strand of DNA.
Information in mRNA is converted into a sequence of amino acids in a protein.
A copy of chromosomal DNA is created in the nucleus.
