Name_______________________________________________
Biology Teacher ________________ Period ________
STAAR Biology EOC Practice Test
1 Prokaryotes are considered by the scientific community as the most ancient life-forms on Earth.
Yet, these primitive cells share many common characteristics with the more modern eukaryotes.
However, one significant difference between these two cell types is that only eukaryotes contain
A membrane-bound compartments to carry out specialized functions
B a selectively-permeable cell membrane to maintain homeostasis
C deoxyribonucleic acid to serve as a template to produce proteins
D a rigid cell wall which provides structure and support
Use the information below to answer the following two questions.
Identical lengths of potato cores were cut and massed. One potato core was then placed in 100 ml of
each of the following solutions; 0M sucrose, 0.2M sucrose, 0.4M sucrose, 0.6M sucrose, 0.8M
sucrose, and 1M sucrose. These were left to equilibrate overnight after which the potato cores were
then removed, patted dry, and massed again. Data is recorded in the table below:
Solution
Initial Mass
Final Mass
0M sucrose
2.2 g
2.4 g
0.2M sucrose
2.4 g
2.4 g
0.4M sucrose
1.9 g
1.8 g
0.6M sucrose
2.0 g
1.8 g
0.8M sucrose
2.2 g
1.8 g
1M sucrose
2.3 g
1.8 g
2 What is the most likely cause of the potato core gaining mass when placed in the 0M sucrose
solution?
A Sucrose moved into the potato core from the solution.
B Sucrose moved from a region of higher concentration to a region of lower concentration.
C Water moved down its concentration gradient.
D Water concentrations stayed the same inside and outside the potato core.
3 The isotonic point in this potato core experiment is closest to
A 0M sucrose because sucrose moved into the potato core causing it to gain mass
B 0.2M sucrose because water didn’t move into or out of the potato core
C 0.2M sucrose because equal amounts of water moved into and out of the potato core
D 1M sucrose because the potato core lost the most mass due to water loss
4 Viruses are considered non-living because they lack the machinery to reproduce on their own and
must rely on a cellular host cell to survive. Structures common to both cells and viruses include
A protein capsid
B nucleic acids
C cell wall
D nucleus
5 Differences between prokaryotes and eukaryotes which are readily observable through the light
microscope include
I. prokaryotes are much smaller than eukaryotes
II. ribosomes are smaller in prokaryotes
III. prokaryotes lack nuclei
A I only
B II only
C I and II only
D I and III only
6 Cells often need to take in materials from their environment, many of which are found in lower
concentrations outside the cell compared to inside the cell. In order to do this, cells must use the
energy from ATP to move these materials
A against the concentration gradient through active transport
B with the concentration gradient through active transport
C against the concentration gradient through passive transport
D with the concentration gradient through passive transport
7 The cellular organelle most directly involved in maintaining homeostasis is the
A plasma membrane
B cell wall
C chloroplast
D mitochondria
8 Viruses are able to infect cells because they share a common genetic code and are able to use
host cell enzymes to carry out protein synthesis. There are some structures which are unique to
viruses and not found in cells. These include
I. Protein capsid
II. Nucleic acids
III. Cell wall
A I only
B II only
C I and II only
D II and III only
9 During an infection, some viruses remain inside cell but do not cause symptoms of disease.
graphic above depicts the
The
A lytic cycle and the host cell is destroyed by rapidly reproducing viral particles
B lytic cycle and the viral nucleic acid inserts into the host cell chromosome
C lysogenic cycle and the viral nucleic acid inserts into the host cell chromosome
D lysogenic cycle and the viral nucleic acid replicates independently of the host cell chromosome
10 The stage of the cell cycle pictured above may be best described as
A Cytokinesis: the cytoplasm of the cell is divided
B S phase: DNA is copied, resulting in identical sister chromatids
C G2 phase: the cell grows in size and prepares to divide the nucleus
D Mitotic phase: the nucleus is divided
11 Leaves are plant organs specialized for photosynthesis. Through the light microscope, which
organelle would be expected to be seen in greater numbers?
A
B
C
D
12 Each of the following statements describes the importance of the cell cycle and Mitosis to an
organism EXCEPT
A The cell cycle and Mitosis are important to produce identical new cells so that a multi-cellular
eukaryote can grow larger.
B The cell cycle and Mitosis are important to produce identical new cells so that a unicellular
eukaryote can reproduce.
C The cell cycle and Mitosis are important to produce identical new cells so that a multi-cellular
eukaryote can repair damaged tissue.
D The cell cycle and Mitosis are important to produce identical new cells so that a multi-cellular
eukaryote can reproduce.
13 According to the illustration, adult stem cells extracted from bone marrow tissue may be cultured
to produce different types of differentiated cells, such as liver cells, nerve cells, and heart muscle
cells. Which of the following statements can best explain this result?
A There are different genes in each of the individual stem cells that are cultured.
B Environmental conditions influence which genes are expressed.
C Each stem cell contains only the DNA required to make one cell type.
D DNA can move from one stem cell to another through the culture media.
14 When harmful mutations occur in genes that contain the information to make cell cycle regulatory
proteins, this may result in accelerated cell division. The result of these mutations is most likely
A cancer
B slower cell growth
C a halt in mitosis
D entry into G0 phase
15 Which of the following illustrations depicts a nucleotide, the building block of DNA?
16Which statement most accurately describes how deoxyribonucleic acid (DNA) carries the genetic
code for building an organism?
A The order of nitrogen bases provides the genetic code
B The genetic code is based on the number of hydrogen bonds found between nitrogen bases
C The number of deoxyribose sugars along the sides of the DNA ladder is used to determine the
genetic code
D The shape of the DNA molecule provides the genetic code
17 Which of the following structures would pair with the nitrogen base Adenine in a complementary
strand of DNA?
18 Restriction enzymes isolated from various bacterial spp. have been extensively used in the
biotechnology laboratory for cutting human genes from DNA samples to insert into bacterial plasmids.
This is made possible because
A Nitrogen bases form a common genetic code for all organisms.
B DNA is maintained in both bacterial and human cells within nuclear membranes.
C Small, circular pieces of DNA called plasmids are common to both humans and bacteria.
D Restriction enzymes cut at random sequences so it does not matter that humans and bacteria use
a different genetic code.
19 The model in the graphic above illustrates translation, the latter part of the process of protein
synthesis. Which other necessary components for translation are absent from the graphic?
A messenger RNA and transfer RNA
B ER membranes and ribosomes
C ribosomal RNA and DNA
D transfer RNA and ribosomes
20 Which of the following statements is NOT correct regarding the process in the illustration above?
A I must be complementary to an mRNA codon.
B This process occurs in the nucleus of a cell.
C III shows the first two amino acids of a growing polypeptide chain.
D The process shown is translation.
21 Bacterial species’ genomes are arranged somewhat differently than those of eukaryotes. Their
circular chromosome contains clusters of genes which code for proteins that work together to
accomplish a series of related tasks. In this way, groups of genes can be turned on when the gene
product(s) are needed, and turned off when they aren’t needed. This confirms the fact that
A Gene expression is a regulated process.
B Genes are arranged similarly in prokaryotes and eukaryotes.
C Eukaryotes have circular chromosomes.
D Bacterial genomes are much larger than those of eukaryotes.
Use the illustration that follows to answer the next two questions:
22 Changes in DNA sequences are called mutations. Mutations may affect only one nitrogen base in
the sequence, or may affect large regions of a chromosome. The particular type of gene mutation
that is illustrated above is called a
A point mutation
B insertion mutation
C frameshift mutation
D nonsense mutation
23 The significance of this gene mutation is that
A A different amino acid sequence results which is likely to affect the functioning of the final protein
product.
B A different amino acid sequence results which is not likely to affect the functioning of the final
protein product.
C No protein product will be produced.
D The protein product is unaffected.
24 Maize is a variety of corn that is often used to illustrate genetic crosses. Since each kernel of corn
on a cob is an offspring, much data can be obtained from observing a single corn cob. Kernels are
found as one of two colors; either purple (P) which is dominant, or yellow (p) which is recessive. If
two heterozygous purple plants were crossed, what would be the predicted phenotype ratio of the
resulting offspring?
A 1PP:2Pp:1pp
B all PP
C 3 purple:1 yellow
D all purple
... .. .
….. ….
SPOTTED SEED
DOTTED SEED
25 Lentil seeds can be found in two varieties based on the different sizes of spots which may be
observed on their outer surface. Seeds with larger spots are called spotted, while seeds with smaller
spots are called dotted. The different-sized spots are inherited in a co-dominant pattern. Predict the
resulting phenotype of offspring if a lentil with spotted seeds were crossed with a lentil that has dotted
seeds.
A Seeds are both spotted and dotted.
B Seeds have intermediate size spots.
C Seeds have no spots.
D Seeds are all spotted.
26 In pea plants, tall (T) is dominant over short (t), and purple flowers (P) are dominant to white
flowers (p). Given two parent plants which are heterozygous for both of these traits, what is the
probability of producing tall offspring with white flowers?
A 9/16
B 3/16
C 1/16
D0
27 Variation is the raw material for change in organisms, providing a mechanism by which
populations may evolve and adapt to changing environmental conditions. Meiosis provides a number
of opportunities for increased variation in sexually reproducing populations through each of the
following events EXCEPT
A crossing over
B independent assortment of alleles
C random distribution of homologous chromosomes
D fertilization
28 Gel electrophoresis and DNA fingerprinting is NOT a useful method for confirming
A the order of nitrogen bases in DNA
B family relationships such as paternity
C a person’s identity
D genes that cause genetic disorders
29 The process of meiosis occurs in sexually reproducing eukaryotes and is important for the
continuation of these species because of all of the following EXCEPT
A Chromosome number is halved in the daughter cells.
B Crossing over during Prophase I provides increased variation.
C Diploid chromosome number is maintained in the zygote.
D Gametes produced are 2n.
30 A baby is born with phenotypic characteristics of Down’s syndrome; a rounded face, small chin,
almond-shaped eyes, and shorter limbs. Evidence from which of these techniques would best
confirm the child has an extra chromosome 21?
A gel electrophoresis
B DNA fingerprinting
C karyotype analysis
D gene therapy
31 The complete amino acid sequence was determined of a protein shared by all primate groups.
The data provided in the graph above shows the percentage of amino acids each primate protein
shared with the human protein. According to this molecular homology data,
A The gorilla is least related to humans.
B The gorilla and chimpanzee are most closely related.
C The chimpanzee is most closely related to humans.
D The chimpanzee is least related to the gibbon.
32 The rock strata were excavated in an area as illustrated above and the fossil remains examined.
According to this information, the most likely scenario is that
A Layer I is the oldest, followed by Layer II, III, and IV.
B Fish suddenly appeared on Earth at the time of Layer III.
C A marine environment gradually filled with sediment and became a terrestrial environment.
D A terrestrial environment was covered by a shallow sea for a period of time.
33 How does competition for limited resources within and between species drive evolutionary
change?
A Individuals with favorable adaptations will out-compete others and produce more offspring.
B Competition makes some individuals stronger than others, and more of the stronger individuals
survive.
C Stronger individuals develop different adaptations than weaker individuals.
D Competition produces variation between populations.
34 Each of the finch varieties pictured evolved from a common ancestral finch species. This diversity
of species likely developed due to
A individuals evolving different traits during their lifetime living longer than others
B finches being born with beneficial variations reproducing more successfully
C immigration of finch species providing a greater variety of traits in the population
D selective predation of one particular variety of finch
35 Cheetahs are the fastest land mammals, yet can only maintain their top speed of about 70 mph for
a few seconds. Since all cheetahs are nearly genetically identical due to a past bottleneck event,
development of future diversity in this species is most likely to occur by
A gene flow
B immigration
C emigration
D mutation
36 The importance of a uniform taxonomic system to the scientific community includes all of the
following EXCEPT
A Binomial nomenclature provides common language.
B Species names are descriptive words.
C Ambiguity of common names is introduced.
D Two or more different kinds of organisms may not have the same name.
37 Which is the best description of how the fossil record provides evidence of common ancestry?
A Analogous structures can be identified between related groups of organisms.
B Homologous structures can be identified between related groups of organisms.
C Molecular homologies can be identified through trace remains.
D Developmental homologies can be identified through fossilized soft tissues.
38 Duck feet are especially well-adapted for life in the water. Sharp claws allow them to better
navigate the wet, slippery environment and webbed toes aid in their swimming ability. These
adaptations probably came about as a result of
A one duck developing these favorable traits over its lifetime and passing them to its offspring
B variation in the duck population; ducks born with one or more of these traits were more
reproductively successful
C nature selecting against these adaptations
D selective breeding of ducks with these favorable traits over many generations
39 The finch beak adaptations in the graphic most likely evolved through the mechanism of
A stabilizing selection
B adaptive radiation
C genetic drift
D non-random mating
40 Species become more diverse to
I. Occupy available niches
II. Reduce competition
III. Adapt to changing environmental conditions
A I and II only
B I and III only
C II and III only
D I, II, and III
Characteristics of species
Unicellular
Nucleated cells
Microscopic
Motile
Inhabits aquatic environments
41 Given the characteristics described in the information box above, this species belongs in kingdom
A Archaebacteria
B Fungi
C Eubacteria
D Protista
42 The organism pictured above, Escherichia coli, is a common symbiont in mammalian digestive
systems. This organism has a circular chromosome located in a region of the cell called the nucleoid
(A), a rigid outer cell wall (B), and a semi-permeable cell membrane (C). To which kingdom does this
organism belong?
A Archaebacteria
B Eubacteria
C Protista
D Fungi
43 Fungi are unique among eukaryotes in that they are
A unicellular
B multicellular
C autotrophic
D decomposers
Use the information in the illustration and table below to answer the next question.
Amphibia
(amphibians)
Cold- blooded
Smooth skin
Aves
(birds)
Mammalia
(mammals)
Osteichthyes
(bony fish)
Chondrichthyes
(cartilaginous fish)
Reptilia
(reptiles)
Warm-blooded
Body covered in
feathers
Body covered in
hair
Body covered in
scales
Body covered in
scales
Body covered in
scales
Warm-blooded
Cold-blooded
Cold-blooded
Cold-blooded
Gills in young,
adults respire
through lungs, skin
lungs
lungs
gills
gills
lungs
44 The animal species in the illustration has the following characteristics; it breathes with lungs,
maintains a constant body temperature, has hair, gives live birth, and nurses young with milk. These
characteristics place the animal in the class
A Amphibia
B Aves
C Mammalia
D Osteichthyes
45 The simple sugar glucose, C6H12O6 , is formed through the process of photosynthesis as depicted
in the chemical equation above. Simple sugars are unique among bio-molecule monomers in that
A They are used by the body for long-term energy storage.
B They do not dissolve readily in water.
C Carbon, hydrogen, and oxygen atoms are always found in a 1:2:1 ratio.
D They are the building blocks of proteins.
46 When comparing the reactants and products of photosynthesis and cellular respiration, which
statement is true?
A Carbon dioxide is a product of photosynthesis.
B Oxygen is a product of cellular respiration.
C Solar energy is converted to chemical energy in the process of photosynthesis.
D Energy is stored in the bonds of glucose in the process of cellular respiration.
47 When compared to the process of photosynthesis, cellular respiration produces more
I.
II.
III.
ATP
CO2
O2
A I only
B II only
C I and II only
D I and III only
48 Enzymes are proteins which function in both metabolic and anabolic pathways in living things.
Which of the following is NOT a characteristic of enzymes?
A Enzymes act as biological catalysts.
B Enzymes slow down chemical reactions.
C Enzymes reduce activation energy needed for a chemical reaction to proceed.
D Enzymes are re-usable.
49 Biomolecule polymers such as proteins, lipids, amino acids, and carbohydrates are formed when
individual monomers are joined through the process of dehydration synthesis. Dehydration synthesis
requires the
A loss of a water molecule
B destruction of a water molecule
C evaporation of a water molecule
D addition of a water molecule
50 Which of these best describes how human body systems interact to protect the body from injury or
illness?
A The skeletal system releases calcium ions into the organs of the respiratory system to encapsulate
bacteria and viruses in the lungs.
B Immune system B-cells are produced in the bone marrow of the skeletal system and introduced
into the blood stream.
C The nervous system stimulates the digestive system to release toxins that kill invading microbes.
D Hormones released by viruses increase both blood pressure and body temperature which work to
inactivate them.
51 Which is the best description of how the organ system pictured above interacts with the circulatory
system to deliver nutrients to cells?
A Nutrients are taken in through the respiratory system and are picked up by the thin walls of
capillaries in the lungs for delivery to the rest of the body’s cells.
B The digestive system processes food into smaller molecules which are picked up for delivery to the
body’s cells by the circulatory system through capillaries in the small intestine.
C The circulatory system moves the secretions from the liver, gallbladder, and pancreas through the
bloodstream for delivery to the stomach where they are used to break down large particles.
D Water recovered from the large intestine is picked up by capillaries and delivered to the stomach to
aid in digestion.
52 Which is the best explanation of how the muscular system aids in delivering nutrients to cells?
A Layers of smooth muscle line the organs of the digestive system, pushing the meal through the
system by involuntary contractions known as peristalsis.
B Teeth mechanically break down food into smaller pieces so enzymes in the digestive system have
a larger surface area to work on.
C Microvilli in the small intestine have a large surface area for small molecules to diffuse from the
digestive system into the bloodstream.
D Large muscles require large amounts of energy to do work.
Before
After
53 Which is the best description of the interactions of plant organ systems to produce the response
illustrated above?
A Stem tips produce a growth hormone which travels through phloem tissues to other parts of the
plant where it causes elongation of cells on the dark side of a stem.
B Leaves which receive excess sunlight produce a wilting hormone that travels to other parts of the
plant through vascular tissues.
C Bright days cause leaves to lose water rapidly, which draws water up from the roots through
vascular tissues at such a pace that stems bend due to the increased water weight.
D Certain chemical substances in the air are taken into leaves through stoma and as they are carried
downward through vascular tissues in the stem the increased weight causes stems to bend.
54 Glucose produced by photosynthesis is stored as starch in storage organs such as potatoes,
onions, and carrots. Which of these is NOT part of the plant system interactions involved in this
process?
A Leaves produce the sugar glucose through photosynthesis.
B Sugars produced by leaves are moved from sink to source by xylem vessels.
C Sugars produced by leaves are moved from source to sink by phloem vessels.
D Root systems store glucose as starch.
55 Which is the most correct description of two plant systems interacting to perform the function of
reproduction in angiosperms?
A Carbon is obtained from the air as CO2 through stoma in the leaves to build all of the
macromolecules needed for reproduction.
B Carbon is obtained from the soil through the root systems and delivered with water and other
nutrients to reproductive organs.
C Most water is obtained in the form of water vapor through leaf pores and delivered through phloem
tissues to reproductive organs.
D Most water is absorbed directly through stoma during rain events and transferred to all parts of the
plant by phloem tissues.
56 Which term contains all of the others?
A tissue
B organ
C organ system
D cell
57 Which of the following statements is least accurate in describing internal feedback mechanisms?
A The excretory system plays a major role in controlling water balance, salt concentrations in the
blood, and removing nitrogenous wastes.
B An imbalance in blood sugar regulation by the competing hormones insulin and glucagon may
result in the disease diabetes.
C Cold-blooded organisms expend less energy than warm-blooded organisms because they lack
control mechanisms to maintain body temperature.
D Positive feedback mechanisms work to maintain levels within a narrow window of parameters,
whereas negative feedback mechanisms push levels beyond the normal range.
58 Microorganisms such as E. coli inhabit the digestive systems of a variety of higher organisms,
including humans. These endosymbionts help their hosts maintain health by all of these EXCEPT
A breaking down food
B producing key nutrients
C infecting adjoining tissues
D competing with harmful microorganisms
59 As the process of ecological succession progresses with time, species diversity tends to
A gradually decrease from colonization to climax community
B be limited in early stages and increase over time
C increase during intermediate stages, then rapidly decrease during the climax community stage
D be highest in the colonization stages
60 Which of these statements best summarizes the change in populations which has occurred during
the stages of succession illustrated above?
A Populations of freshwater fish and aquatic plants are gradually replaced by populations of weeds
and grasses as a pond fills with silt.
B A terrestrial ecosystem is replaced by a freshwater ecosystem.
C A marine ecosystem is replaced by a terrestrial ecosystem.
D Populations of freshwater fish and aquatic plants die off as their habit becomes filled with silt.
61 Eliminating microorganisms from an ecosystem would have all of the following effects EXCEPT
A increased carbon dioxide available to plants
B plants starved of key nitrogen-containing nutrients
C food chains disrupted
D decomposition would halt
62 Termites are incapable of digesting the wood fibers they ingest, but maintain a population of
symbiotic bacteria in their gut which break down the wood fiber for them. This relationship is best
described as
A parasitism
B mutualism
C predation
D commensalism
63 The deer tick must feed on the blood of warm-blooded mammals in order to survive. At times, as
the tick feeds it also transmits harmful bacteria to the host which cause lyme disease. This
relationship is an example of
A parasitism
B mutualism
C predation
D commensalism
Organism
A. Snowshoe
hare
Adaptation #1
Large, furry
feet
B. Kangaroo rat Small-bodied
C. Prairie dog
Sharp teeth to
eat tough
grasses
D. Tarsier
Arboreal, living
almost
exclusively in
trees
Adaptation #2 Adaptation #3
Rounded and
Extra thick fur
reduced ear
size
Large ears
with lots of
blood vessels
to release
body heat
Strong hind
legs allow
them to stand
upright to
guard burrows
Flattened nails
assist in
capturing
insects
Burrows
underground
during the day
Lives in
underground
tunnels to
escape
extreme
temperatures
and predators
Large eyes
with excellent
sight for
nocturnal
hunting
Adaptation #4
Fur changes
color; brown in
summer, white
in winter
Increased
ability to
concentrate
urine
Receive water
they need from
food
Long limbs and
tail make the
tarsier an
excellent
climber and
jumper
64 Based on the adaptations listed in the table above, which organism is best suited for life in the
tropical rainforest ecosystem?
A.
B.
C.
D.
Snowshoe hare
Kangaroo rat
Prairie dog
Tarsier
65 In the food web above, which organisms are most likely to become overpopulated if there were a
larger than average production of seeds during a growing season?
A grouse
B chipmunk
C elk
D grizzly bear
66 What is the best explanation of why the numbers of organisms at each trophic level decrease from
the bottom of the pyramid to the top?
A The organisms increase in size as you move up the pyramid.
B Energy is used for life processes and lost as heat at each trophic level.
C Energy is wasted at each trophic level.
D There is more sunlight available to the first trophic level.
67 Carbon flows cyclically through organisms and the environment. Which of the following
descriptions of the carbon cycle is NOT correct?
A Major reservoirs of carbon include tropical forests, oceans and fossil fuels.
B Carbon dioxide is produced through photosynthesis and used in cellular respiration.
C Humans may disrupt the carbon cycle by burning fossil fuels which may result in global warming.
D Carbon is released to the atmosphere in the form of CO2 through respiration in living things.
68 In an ecosystem, the simple food chain above shows the movement of matter and energy from
one organism to the next. If disease reduced the number of organisms at the producer level, which
other organism would feel the greatest effect?
A the mouse because it is a producer
B the mouse because it eats producers
C the cat since it is a 2nd order consumer
D the coyote because it is the top consumer in the food chain
69 The graph depicts the growth of a population of yeast cells over time. The red line most likely
represents
A the limit of tolerance of the yeast cells to environmental conditions
B the highest number of yeast cells the population can achieve
C the carrying capacity of the environment
C population size of a predator which preys on the yeast
Use the information in the following paragraph for the next question
Throughout the decade of the 1930’s, a series of severe dust storms blew across the prairie lands of
the United States, causing extreme ecological and agricultural damage. Years of poor farming
practices and drought resulted in the loss of tons of topsoil to prevailing winds. Millions of acres of
land became barren and uninhabitable.
70 Which is the best description of how this event likely impacted the natural prairie ecosystem that
inhabited the area?
A Carrying capacity of the environment increased.
B The mature prairie community was replaced with weedy species.
C Biodiversity increased.
D Primary succession occurred.
71. Which of the following most accurately shows diffusion ?
solute
A.
B.
C.
D.
Observe the cell below to answer the next two questions.
1
2
3
5
4
6
7
72. The rough ER is represented by which letter ?
A. 2
B. 3
C. 5
D. 6
73. The organelle where cellular respiration takes place and glucose is converted into ATP
energy is represented by
A. 2
B. 4
C. 5
D. 6