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Biology STAAR Mini-Test [2026]

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This is a (very) shortened version of the actual STAAR test! It includes some of the different question types that may appear on the actual STAAR test.

Answer all questions to the best of your ability, without using any notes, online resources, or other students to help you. Just try your best and give yourself a chance to see how you would actually do on these questions on the real STAAR test!

You can navigate back and forth between questions as much as you need to before your final submission. Make sure you are happy with your answers before you submit at the end of the assignment!
Question 1
1.

Question 2
2.
A genetic sequence undergoes a mutation. The original sequence, the mutated sequence, and a codon chart are shown.
How many amino acid changes can be identified from the mutated sequence shown?

Record your answer in the space provided.

_______
Question 3
3.

This question has two parts. First, answer Part A. Then, answer Part B.

Question 4
4.

A population of organisms contains multiple alleles for a particular trait. A biologist assigns each allele a letter from M through T and tracks the frequency in a population. A small group of organisms travels to a new location and begins a new population.

The biologist tracked the allele frequency for the trait in the original population and the small group and recorded the data in the tables shown.

Which table shows the MOST LIKELY allele frequency of the new population?

Question 5
5.

A student is sweating after playing basketball.

Which body systems are MOST DIRECTLY interacting as a response to maintain homeostasis?

Question 6
6.

A student makes a model of an energy pyramid by stacking cups as shown. The producers are represented by the bottom level of four cups.
How much energy will be obtained at the top of this energy pyramid if the cups representing the primary consumers have 37,000 kilojoules (kJ) of energy?

Question 7
7.

In animal cells, the sodium-potassium pump moves sodium and potassium ions against a concentration gradient across the cell membrane.

What type of transport is used, AND why is this type of transport necessary?

Read the question carefully. Then enter your answers in the space below.

Question 8
8.

A student makes a model to compare the process of transcription and translation to the process of using a grocery store that prepares orders for customers.
Based on the student’s model and your knowledge of the biological process, which person or object represents tRNA?

Question 9
9.

Which table correctly matches each type of biomolecule with its function in the cell membrane?

Question 10
10.
A Venn diagram comparing the functions of proteins and nucleic acids is shown.

Which functions BEST complete the Venn diagram?

Select the correct answer for each box. Not all answers will be used.
Other Answer Choices:
Encode genetic information
Provide insulation
Transport substances
Are stored as glycogen
Provide energy
Are involved in translation
Question 11
11.

A student is drawing an energy pyramid.

Examine the diagram and answer these questions:
  • What is the original source of all energy for the energy pyramid?
  • How does the amount of energy available at each level of the pyramid change from the bottom to the top?

Question 12
12.

Microorganisms are known to be present in some food products such as yogurt. One student claims that microorganisms in food always have a negative effect on human health, while a second student disagrees. The second student claims that some microorganisms in food can have a positive effect on human health.

Which statement BEST supports the second student’s claim?

Question 13
13.

There are different types of human blood cells. Depending on what type they are, some blood cells either carry nutrients throughout the body or destroy foreign substances in the body.

Which statement explains how genes control the differentiation of
different types of blood cells?

Question 14
14.

Which two components are MOST LIKELY found in both viruses and prokaryotic cells?

Question 15
15.

Which cellular components are the same in all living organisms?

Question 16
16.

Which statement BEST describes how genes are expressed in an organism?

Question 17
17.

Which environmental condition would MOST LIKELY result in the appearance of punctuated equilibrium in the fossil record?

Question 18
18.

The graphs show changes in allele frequencies in a population at three points in time as a drought becomes more severe.









Which statement best describes how natural selection affects alleles?

Question 19
19.

Which statement BEST describes the roles of glucose and oxygen in photosynthesis?

Question 20
20.
Leguminous plants, such as bean plants, share a mutualistic relationship with certain rhizobium bacteria. The plants develop harmless nodules on their roots, where the bacteria live. In return, the bacteria convert an important element from the atmosphere into a nutrient form that the plants can use.

What essential element is converted to a useable form by the rhizobium bacteria?

Record your answer in the space provided.
_______
Question 21
21.
This question has two parts.

In cattle, the hornless trait is dominant to the horned trait. A farmer starts with a herd of cattle heterozygous for the horned trait and wants to keep the herd hornless. To keep the hornless trait, the farmer builds fences around the farm to prevent the cattle from mating with any horned cattle in the area.

Part A
Which statement describes what will MOST LIKELY happen to the cattle population on the farm over time?

__________

Part B
Which evidence supports your answer in Part A?

__________
Question 22
22.

Some inherited health disorders are caused by nondisjunction. During nondisjunction, homologous chromosomes fail to separate properly during the formation of sex cells.
Based on the images, which cells MOST LIKELY show examples of nondisjunction?

Select TWO correct answers.

Question 23
23.

The snowshoe hare often molts, or sheds its fur, during different seasons, going from a reddish brown to a white fur color.

The graphs show both the change in coat color in one population of snowshoe hares and the average snow coverage during two periods of the year.


Which statement BEST explains the data shown in the graphs?

Question 24
24.

The uptake of nitrogen by plants would likely be MOST affected by which occurrence?

Question 25
25.

The population of an invasive crab species, Callinectes sapidus, is rapidly increasing along coastal Europe. This aggressive, fast-growing omnivore reproduces quickly and is causing the extinction of many native species.

Which statement BEST describes the effect of a native species’ extinction on local ecosystem biodiversity and stability?

This is the end of the practice test! Make sure you have finalized all of your answers before you submit this assignment.


After you submit the assignment, you will be able to see whether or not you got the answers correct for each question, except for the short constructed response (free response) questions that can't be auto-graded.

DO NOT CLOSE THIS TAB AFTER YOU SUBMIT! You will need to keep this tab open while you complete the reflection assignment, as it will require you to look back at your responses.

A student studying mitosis captures an image of cells from an onion root tip with a camera mounted on a microscope.
Which events occur after the phase circled in the student’s image?

Select TWO correct answers.
The nuclear membrane disappears.
Chromosomes attach to spindle fibers.
Spindle fibers form.
Paired chromosomes separate.
Chromosomes condense.
The cytoplasm separates into two cells.
3,700 kJ
The shopper
Microorganisms can destroy any pathogens that affect the immune system.
Different genes are expressed in the different types of blood cells.
Natural selection affects allele frequencies in individuals, not in populations.
Natural selection affects allele frequencies differently depending on how helpful an allele is to an organism’s fitness for its environment.
Natural selection affects alleles randomly, leading to small changes in allele frequencies.
Natural selection always affects how the same allele influences an organism’s reproductive success.
Hares change their fur color as a result of mating choice during the spring months.
Natural selection allows for mutations to occur during seasonal changes when food is abundant.
Extinction leads to decreases in biodiversity and increases in stability