ULTIMATE STAAR REVIEW 2025-2026

Multiple Choice

What organelle is found in all eukaryotic cells but NOT in prokaryotic cells?

• cell wall

• nuclues

• cell membrane

• cytoplasm

Multiple Choice

4A Students use a microscope to look for structures present in four different cells. The students placed an X for each structure that was viewed for each cell on the table shown.

Which cell that was viewed is most likely a prokaryote?

• Cell W

• Cell X

• Cell Y

• Cell Z

Multiple Choice

____________ & _________________ are organelles that definitely arose from endosymbiosis.

• Rough ER & Smooth ER
• Mitochondria & Flagellum
• Chloroplast & Mitochondria
• Chloroplast and Golgi apparatus

Multiple Choice

The theory of Endosymbiosis explains

• The origin of eukaryotes
• How species develop
• How bacteria live
• Why cells rely on one another

Multiple Choice

What evidence does not support the evolution of chloroplasts and mitochondria from prokaryotic cells?

• fossil record

• double membrane of organelles

• similar methods of reproduction

• presence of circular DNA

Multiple Choice

How does the cell membrane help to maintain the health of the cell?

• By providing support and structure for the cell

• By regulating the transport of materials in and out of the cell

• By manufacturing protein to provide energy for the cell

• By storing food as future energy for the cell

Multiple Choice

The cell membrane is semi-permeable. What does that mean?

• that the cell membrane lets ALL things in and out of the cell

• that the cell membrane lets NO things in and out of the cell

• that the cell membrane lets SOME things in and out of the cell

Multiple Choice

Is a virus considered living or non-living?

• Living
• Non-Living
• Neither

Multiple Choice

4C: Which of these describes a difference between viruses and cells?

• Cells contain protein, and viruses only contain carbohydrates

• Viruses have flagella, and cells have only cilia

• Cells reproduce independently, and viruses require a host to reproduce

• Viruses have membranes made of proteins, and cells have membranes made of nucleic aci

Multiple Choice

What do viruses have in common with living cells? They both...

• store genetic information
• have chloroplasts
• use glucose for cellular respiration
• have endoplasmic reticulum

Multiple Choice

Some examples of things that can cause the cell cycle to become abnormal are

• carcinogens

• UV radiation

• Viruses

• All of the above

Multiple Choice

Here is the cell cycle. 

When cells leave the cell cycle, they exit during G1 phase and enter G0 phase, a resting period. Most normal cells can leave G0 phase and re-enter the cell cycle at G1 before entering S phase. Cancer cell are different because they cannot enter G0 phase and are likely to do which of the following?

• Fail to complete S phase

• Mutate during G1 phase

• Repeat the cell cycle continuously 

• Die after completing mitosis

Multiple Choice

Cancer is caused by

• Out of control DNA replication

• Out of control cell cycle caused by damaged DNA

• Out of control cell cycle caused by cyclins

• Tumors

Multiple Choice

Undifferentiated cells are called:

• stem cells

• nerve cells

• eye cells

• skin cells

Multiple Choice

Cell expression is regulated by:

• internal factors

• external factors

• both

Multiple Choice

All your cells have the same:

• shape

• size

• DNA

• Transcription factors

Multiple Choice

6A In 1952 Rosalind Franklin took the x-ray photograph shown, which gave the world its first look at DNA.

By studying this photograph, scientists gained knowledge about the —

• role of DNA in protein synthesis

• mutation of nucleotide sequences in DNA

• sequence of DNA that makes up the human genome

• double-helix structure of DNA

Multiple Choice

6A: Which part of a DNA molecule is responsible for the direct coding of specific traits in an organism?

• The number of hydrogen bonds that hold the strands of DNA together

• The number of carbons in the DNA molecule

• The sequence of nucleotide bases in the DNA molecule

• The sequences of phosphates along each DNA strand

Multiple Choice

6A A segment of a DNA strand is shown.

3’ AGGTCAGGT 5’

Which of these is the correct complementary DNA strand for the segment shown?

• 5’ AGGTCAGGT 3’

• 5’ ACCUGAGGU 3’

• 5’ TGGACTGGA 3’

• 5’ TCCAGTCCA 3’

Multiple Choice

DNA replication results in

• 2 completely new DNA molecules

• 2 DNA molecules that each contain a strand of the original

• 1 new DNA molecule and 1 old

• 1 new molecule of DNA

Multiple Choice

Why does DNA replicate?

• To create another copy for the new cell
• To create a duplicate copy in case the original gets damaged
• To create a new copy to replace the damaged original

Multiple Choice

A process in which DNA has the unique ability to make an exact copy of itself.

• Replication
• Translation
• Transcription

Multiple Choice

Researchers combined sequences of fruit-fly DNA from a gene for a particular trait with frog DNA. The mixture was heated to separate the DNA strands. Cooling allowed the single strands to form pairs. The researchers observed that some of the fruit-fly DNA paired with frog DNA. The results provide evidence that -

• similar nucleotides are present in both fruit-fly and frog DNA

• fruit flies and frogs can be made to develop some of the same physical traits

• heat can cause mutations in the DNA sequences of organisms

• the replication of genetic material can occur at any temperature

Multiple Choice

Which of these components are found in the cells of all living organisms?

• estrogen and testosterone

• hemoglobin and lymphocytes

• cytosine and guanine

• cellulose and chlorophyll

Multiple Choice

6C: The initial steps in gene expression are modeled above. Double-stranded DNA first unwinds into two strands. 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

Multiple Choice

What amino acid is represented by the codon UUA?

• Phenylalanine

• Tyrosine

• Leucine

• Stop codon

Multiple Choice

Transcribe the following DNA to mRNA

TAC ATT CGA AAA

• ATG TAA CGA TTT

• AUG UAA GCU UUU

• AUG UAA GCU AAA

• AUG UTT GCU UUU

Multiple Choice

DNA molecule segment is : TTA-CGC-AAG

The mutated DNA segment is TTC-GCA-AG. This is an example of ___ mutation.

• Substitution

• Deletion

• Insertion

• Inversion

Multiple Choice

What mutation has occurred here?

T-G-A-C-C-A

T-G-A-G-C-A

• Substitution

• Deletion

• Insertion

• Frameshift

Multiple Choice

Meiosis makes which kind of cells?

• sex cells

• skin cells

• eye cells

• hair cells

Multiple Choice

6G: During meiosis, homologous chromosomes exchange genetic material. This exchange of genetic material:

• increases the genetic variation

• reduces the diploid number to the haploid number

• increases the haploid number to the diploid number

• reduces the probability of mutations

Multiple Choice

What is the significance of crossing over during meiosis?

• Genes from the mother and the father combine to increase the variety of traits expressed by their offpsring

• Gametes duplicate and alter the number of chromosomes present at the end of meiosis

• Gametes begin with 48 chromosomes and still have 48 chromosomes at the end of meiosis

• Genes replicate and ensure that the offspring have the same traits as the parents.

Multiple Choice

T - tall and t = short
In the punnett square below, what belongs in the missing square

• tt
• Tt
• Bb
• TT

Multiple Choice

Cross Two Homozygous plants
(RRYY x rryy)
R = round seeds, r  = wrinkled seeds Y = yellow seeds, y = green seeds
What percent will have Round and Yellow seeds? 

• 0%
• 25%
• 50%
• 100%

Multiple Choice

If two organisms have similar traits of DNA they are probably

• share a common ancestor
• share a common environment
• share a common population
• speciation

Multiple Choice

The opossum and kangaroo both incubate their young in a pouch. This provides evidence that they---

• are descended from a common ancestor
• Have very similar skeletal structures
• belong to the same species
• must range great distances to eat

Multiple Choice

Similar structures with different purposes found in different species are known as _____

• vestigial structures

• DNA

• homologous structures

• the fossil record

Multiple Choice

Only populations can evolve.
Individuals can not evolve.

• True
• False

Multiple Choice

Which of the following is an example of natural selection?

• Birds migrating south for the winter

• Hamster with different colors of fur

• Butterflies come in many different varieties

• A purple insect is more likely to survive in a field of purple colored flowers than an orange insect

Multiple Choice

Yellow toucan birds seek out one another to make babies together and tend to avoid the green toucan birds.

• Genetic Drift
• Non-random mating
• Gene flow
• Mutation

Multiple Choice

Five hundred years after the deer had established a flourishing population in the park, a few of them venture back to their original woods and have babies with the deer there.

• Genetic Drift
• Mutations
• Non-random mating
• Gene flow

Multiple Choice

What does the image represent?

• Gene flow
• Gene drift
• Mutation
• Adaptation

Multiple Choice

The 8 levels of classification, most broad to most specific.

• Domain, Genus, Family, Order, Class, Phylum, Kingdom, Species
• Domain, Species, Kingdom, Genus, Phylum, Family, Class, Order
• Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
• Order, Kingdom, Species, Domain, Phylum, Family, Class, Genus

Multiple Choice

The scientific name for an organism is made from the:

• class and family name
• genus and species name
• domain and kingdom name
• kingdom and phylum name

Multiple Choice

Which of the following organisms are most DISTANTLY related?

• organisms that share a domain

• organisms that share a family

• organisms that share a genus

• organisms that share a species

Multiple Choice

Plants and animals belong to which domain?

• bacteria

• archaea

• eukarya

Multiple Choice

This is Yellowstone National Park, where hot springs like these are found. These springs are HOT and only certain types of bacteria can live there. In which domain do bacteria these bacteria belong?

• bacteria

• archaea

• eukarya

Multiple Choice

I am prokaryotic and am found everywhere. What kingdom do I belong to?

• Eubacteria

• Archaebacteria

• Fungi

• Protista

Multiple Choice

Members of this kingdom are multicellular and heterotrophic.

• Plantae
• Protista
• Animalia
• Achaebacteria

Multiple Choice

An illustration and a dichotomous key are given. What is the correct classification for this organism?

• Class Insecta
• Order Amblygygi
• Order Araneae
• Order Scorpiones

Multiple Choice

According to the cladogram, which organism is most distantly related to the human?

• crayfish
• grasshopper
• perch
• frog

Multiple Choice

On the cladogram, which feature do all organisms inherit?

• A
• B
• C
• D

Multiple Choice

What is a function of carbohydrates?

• provide short term energy

• provide the structure in muscles

• provide long term energy

• store genetic information

Multiple Choice

Proteins are made of monomers called

• saccharides

• nucleotides

• amino acids

• fatty acids

Multiple Choice

What is the function of proteins?

• They are used for cell to cell communication

• They insulate the body, are used for short term energy and are found in glycogen

• They are used as the structural components of the body (muscles and organs)

• They create the cell membrane

Multiple Choice

Which biomolecule is correctly paired with its function?

• Lipids - express genes

• Protein - form enzymes

• Carbohydrates - create hormones

• Nucleic acids - insulate animal tissue

Multiple Choice

Which is the most valid conclusion based on this graph?

• Enzymes are not affected by temperature.

• Enzymes work most effectively at low temperatures.

• Raising the temperature always makes an enzyme work better

• Enzyme function decreases after a certain optimal temperature

Multiple Choice

What is the main purpose of cellular respiration?

• make glucose

• make energy

• make sunlight

• use carbon dioxide

Multiple Choice

Products are

• inputs

• outputs

• waste

• ingredients

Multiple Choice

Reactants are

• inputs

• outputs

• waste

Multiple Choice

Analyze the graphic above. What are the chemicals represented by the Y?

• H₂O +O₂

• H₂O + CO₂

• C₆H₁₂O₆ + O₂

• C₆H₁₂O₆ + CO₂

Multiple Choice

What 2 systems: Controls the production of sex cells

• Excretory and Reproductive

• Endocrine and Reproductive

• Endocrine and Muscular

• Endocrine and Respiratory

Multiple Choice

What 2 systems: Transports white blood cells throughout the body to fight disease

• Excretory and nervous

• Circulatory and immune

• Respiratory and nervous

• Digestive and immune

Multiple Choice

10B: A student conducted an investigation to study phototropism in grasses. The only different between the control group and the experimental group was light conditions. The control group was provided full light, while the experimental group was shaded on one side. The diagrams show the average heights and positions of blades of grass in the investigation. Which statement best explains why the grass tips of the experimental group bent toward the light?

• Water evaporated faster on the side of the plant having full light

• Light sensors in the grass tips stimulated a hormone in the shoot system

• The xylem in the root system absorbed more nutrients from the shaded side

• The side facing the light has a greater chance of absorbing carbon dioxide from the atmosphere

Multiple Choice

10B: Plant roots have extensions called root hairs. These root hairs are important in the homeostasis of the plant. Which statement best explains the importance of the root hairs to the stems and leaves of the plant?

• Root hairs convert minerals into glucose for immediate use by cells

• Root hairs decrease the need for osmosis and diffusion in vascular tissue

• Root hairs prevent water loss in leaves through transpiration and gas exchange

• Root hairs increase the surface area of the roots for nutrient and water absorption

Multiple Choice

Which is NOT a microorganism?

• fungi

• bacteria

• pollen

• protist

Multiple Choice

Primary succession occurs in areas with:

• very little soil

• lots of soil

• no soil

• soil that has been disturbed

Multiple Choice

Which of the following best describes primary succession?

• Volcano wipes out ecosystem that gradually grows back from ash covered soil

• Volcano creates a new island of rock that must break down to form an ecosystem

• Forest fire burns down forest that must bounce back over time

• Tornado destroys a crop that must slowly grow back over time.

Multiple Choice

How is commensalism different from mutualism?

• In commensalism, one species benefits while the other is unharmed; in mutualism, both species benefit

• In commensalism, one species is harmed while the other benefits; in mutualism, both species benefit

• In commensalism, neither species is harmed; in mutualism, one species is harmed

• In commensalism, both species benefit; in mutualism, one species is harmed

Multiple Choice

Which of the following is an example of symbiosis?

• A mother bear taking care of her cub

• A married couple who agree to split their rent and share housework duties

• A worm living in a cow's intestine.

• One chimp cleaning and grooming the hair of another chimp.

Multiple Choice

What are plants called in a food chain?

• Producers
• Consumers
• Decomposers
• Scavengers

Multiple Choice

Which of these organisms would receive energy from the snake?

• Plant
• Rabbit
• Mouse
• Hawk

Multiple Choice

Which of these organisms would receive energy from the snake?

• Plant
• Rabbit
• Mouse
• Hawk

Multiple Choice

How much energy is transferred from one trophic level to the next in an energy pyramid?

• 1%

• 10%

• 100%

• 90%

Multiple Choice

Cannot make its own food

• Autotroph

• Producer

• Heterotroph

• Biomass

Multiple Choice

Makes its own food

• Herbivore

• Carnivore

• Heterotroph

• Autotroph

Multiple Choice

Consider the following food chain:

Algae > Mayfly > Minnow > Trout

In a polluted ecosystem, which organism would likely have the HIGHEST level of toxic chemicals in its body?

• Algae

• Mayfly

• Minnow

• Trout

Multiple Choice

Which ecological nutrient cycle relies heavily on bacteria to "fix" an important nutrient by converting it from atmospheric gas to a form that can be absorbed by plants?

• Carbon Cycle

• Nitrogen Cycle

• Phosphorus Cycle

Multiple Choice

The pollution of local waterways and aquatic ecosystems by excess nutrients from fertilizers can lead to algae blooms and the death of aquatic organisms in a process known as...

• Eutrophication

• Fertilization

• Nutrification

• Denitrification

Multiple Choice

Which ecological nutrient cycle relies on photosynthesis and respiration?

• Carbon Cycle

• Nitrogen Cycle

• Phosphorus Cycle

Multiple Select

Which is true about stable ecosystems?

• Healthy ecosystems have high biodiversity.

• Stable ecosystems have more consumers than they can support.

• Stable ecosystems have too many producers.

Multiple Choice

Which of the following would be the most likely effect, if there were a sudden increase in the cricket population?

• There would be a decrease in the small bird population.
• There would be a decrease in the grass/flowers population.
• There would be a decrease in the mice population.
• There would be an increase in the grass/flowers population.

Multiple Select

Which of the following alleles is homozygous recessive? Select two answers.

• Tt
• tt
• TT
• BB

• bb

Multiple Choice

The following items are examples of __________.

Items: eye color, hair color, height

• homozygous alleles

• genotype

• heterozygous alleles

• phenotype

Multiple Choice

Crossing over creates new combinations this causes

• increase cell numbers

• increase in genetic variation

• decrease in genetic variation

Multiple Choice

How Many chromosomes are in a Diploid Cell?

• 21

• 45

• 46

• 23

Multiple Choice

How many chromosomes are in a Haploid Cell?

• 21

• 12

• 23

• 46

Multiple Select

What do all living organisms have in common ? select all that apply.

• Base pairing

• Exact DNA sequence

• Codons

• Amino acids

• Proteins

Multiple Choice

The similarities in embryonic development shown in the diagrams suggest that these organisms -

• develop the same exact way

• may have evolved from the same common ancestor

• are all the same species

• have the same adaptations as adults

Multiple Choice

The science of describing, classifying, and naming living things is called:

• Geology

• Biology

• Taxonomy

• Chemistry

Multiple Choice

A scientific name consists of 

• Genus and Order

• Genus and Domain

• Genus and species

• Kingdon and Phylum

Multiple Choice

If B = brown hair and b = blonde hair, what is the probability of brown hair?

• 25%
• 50%
• 0%
• 75%

Multiple Choice

Amount of energy in a food pyramid transferred from one level to the next

• 0%

• 10%

• 78%

• 100%

Multiple Choice

Which of the following statements are true?

• All microorganisms are bad
• All microorganisms are good
• Some microorganisms are harmful, while some can be helpful
• Microorganisms are too small to do anything to anyone