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MTTC Biology (017) study materials
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MTTC Biology (017) practice questions

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Question 1Biology

A cell biologist treats a sample of cells with a drug that blocks the formation of the mitotic spindle. During which stage of mitosis would these cells arrest?

  1. Telophase
  2. Anaphase
  3. Metaphase Correct answer.
  4. Prophase

Explanation

The spindle apparatus is required to attach to kinetochores and align chromosomes at the metaphase plate. When spindle formation is blocked, chromosomes cannot achieve proper bipolar attachment, so the spindle assembly checkpoint halts the cell before anaphase begins.

Question 2Biology

Which property of the phospholipid bilayer most directly explains why small nonpolar molecules such as oxygen cross membranes readily while ions do not?

  1. The hydrophobic interior excludes charged particles. Correct answer.
  2. The bilayer is impermeable to water.
  3. The bilayer contains cholesterol that binds ions.
  4. Peripheral proteins actively pump all ions.

Explanation

The fatty acid tails create a hydrophobic core that dissolves nonpolar gases but repels charged and highly polar solutes. Ions therefore require channels or transporters to cross, whereas oxygen diffuses through the lipid phase.

Question 3Biology

In a population at Hardy-Weinberg equilibrium, the frequency of the recessive allele is 0.3. What proportion of the population is expected to be heterozygous?

  1. 0.09
  2. 0.49
  3. 0.21
  4. 0.42 Correct answer.

Explanation

Heterozygote frequency is 2pq. With q = 0.3, p = 0.7, so 2(0.7)(0.3) = 0.42.

Question 4Biology

A mutation changes a single DNA base in a coding region but the resulting polypeptide has the same amino acid sequence. This is best described as which type of mutation?

  1. Nonsense
  2. Missense
  3. Silent Correct answer.
  4. Frameshift

Explanation

Because the genetic code is degenerate, a base substitution can change a codon without changing the encoded amino acid. Such a change is called a silent mutation and leaves the polypeptide unchanged.

Question 5Biology

Which statement best describes the role of the electron transport chain in oxidative phosphorylation?

  1. It converts pyruvate into acetyl-CoA for the citric acid cycle.
  2. It directly phosphorylates ADP using substrate-level phosphorylation.
  3. It reduces NAD+ to regenerate NADH for glycolysis.
  4. It establishes a proton gradient that drives ATP synthase. Correct answer.

Explanation

Electron transfer through the chain pumps protons across the inner mitochondrial membrane, creating an electrochemical gradient. ATP synthase then uses the proton-motive force to phosphorylate ADP.

Question 6Biology

In a dihybrid cross of two heterozygotes (AaBb × AaBb) with independent assortment, what fraction of offspring is expected to show both recessive phenotypes?

  1. 9/16
  2. 3/16
  3. 1/16 Correct answer.
  4. 1/8

Explanation

Each recessive phenotype appears with probability 1/4, and independent assortment lets the probabilities multiply. The product is 1/4 × 1/4 = 1/16.

Question 7Biology

Which of the following best explains why the fossil record provides an incomplete picture of evolutionary history?

  1. Fossils preserve soft tissue more often than bone.
  2. Evolutionary change stopped before fossils formed.
  3. Fossilization requires rapid burial and durable hard parts. Correct answer.
  4. All extinct species left fossil remains.

Explanation

Fossils form only under specific conditions, typically requiring rapid burial and preservation of hard parts. Many organisms, especially soft-bodied ones, decay before fossilization, leaving gaps in the record.

Question 8Biology

Two species of finch live on the same island and eat seeds of different sizes, with each species specializing on a distinct seed size. This is an example of which ecological interaction?

  1. Parasitism
  2. Mutualism
  3. Resource partitioning Correct answer.
  4. Competitive exclusion

Explanation

When species divide a limited resource by using different portions of it, they reduce competition and can coexist. This division is called resource partitioning.

Question 9Biology

Which structure in a flowering plant produces the male gametophyte?

  1. Anther Correct answer.
  2. Stigma
  3. Ovule
  4. Style

Explanation

The anther contains microsporangia where microspores develop into pollen grains, which house the male gametophyte. The ovule, stigma, and style are female reproductive structures.

Question 10Biology

A biologist observes that a particular enzyme shows a high reaction rate at pH 7 but nearly no activity at pH 3. Which explanation is most consistent with this observation?

  1. Low pH increases substrate concentration.
  2. Low pH denatures the enzyme by disrupting its tertiary structure. Correct answer.
  3. Low pH converts the enzyme into a competitive inhibitor.
  4. Low pH raises the activation energy of the reaction.

Explanation

Extreme pH alters ionization states and disrupts hydrogen bonds and ionic interactions that maintain tertiary structure. Loss of proper active-site shape reduces catalytic activity.

Question 11Biology

Which component of a DNA nucleotide distinguishes it from an RNA nucleotide?

  1. The deoxyribose sugar Correct answer.
  2. The hydrogen bonding pattern
  3. The phosphate group
  4. The nitrogenous base

Explanation

DNA contains deoxyribose, which lacks the 2'-hydroxyl group present on ribose in RNA. This sugar difference is the defining structural distinction between the two nucleic acids.

Question 12Biology

A student sequences a gene and finds that a coding region contains the sequence TAC. If this codon is transcribed and translated, which amino acid is specified?

  1. Methionine
  2. Stop
  3. Tyrosine Correct answer.
  4. Histidine

Explanation

The DNA triplet TAC is transcribed to the mRNA codon AUG, but here the question refers to the coding-strand triplet TAC, which corresponds to mRNA codon UAC. UAC codes for tyrosine.

Question 13Biology

In a pedigree, a trait appears in every generation, affects both males and females roughly equally, and an affected father passes it to all of his daughters but none of his sons. Which mode of inheritance is most consistent?

  1. Y-linked
  2. X-linked dominant Correct answer.
  3. Autosomal dominant
  4. Autosomal recessive

Explanation

An affected father passing the trait to all daughters and no sons is the hallmark of X-linked dominant inheritance, since daughters receive his X chromosome and sons receive his Y. Appearance in every generation and equal sex distribution are also consistent.

Question 14Biology

Which of the following is the primary function of the loop of Henle in the mammalian kidney?

  1. Filtration of blood plasma
  2. Establishment of an osmotic gradient for water reabsorption Correct answer.
  3. Secretion of hydrogen ions
  4. Reabsorption of glucose

Explanation

The loop of Henle creates a concentration gradient in the medulla through countercurrent multiplication. This gradient allows water to be reabsorbed from the collecting duct under the influence of ADH.

Question 15Biology

A muscle cell is stimulated repeatedly without relaxation, and the resulting tension is greater than that of a single twitch. This phenomenon is called which of the following?

  1. Recruitment
  2. Summation failure
  3. Tetanus Correct answer.
  4. Fatigue

Explanation

When stimuli arrive rapidly enough that calcium remains elevated and the muscle does not relax between twitches, tension builds and fuses into a sustained contraction called tetanus.

Question 16Biology

Which of the following best describes the role of the Calvin cycle in photosynthesis?

  1. It generates a proton gradient across the thylakoid membrane.
  2. It uses ATP and NADPH to fix carbon dioxide into sugars. Correct answer.
  3. It splits water to release oxygen.
  4. It transfers electrons from photosystem II to photosystem I.

Explanation

The Calvin cycle uses ATP and NADPH produced by the light reactions to reduce carbon dioxide and build carbohydrates. It occurs in the stroma and does not require light directly.

Question 17Biology

A researcher finds that a particular species of bird has a beak size that varies continuously and is strongly influenced by many genes. Which type of natural selection is most likely to act on this trait?

  1. Stabilizing selection on a polygenic trait Correct answer.
  2. Disruptive selection on a single allele
  3. Directional selection on a single locus
  4. Sexual selection on a discrete trait

Explanation

Polygenic traits show continuous variation and are often subject to stabilizing selection, which favors intermediate phenotypes. This reduces extremes and maintains the population mean.

Question 18Biology

Which of the following is a key difference between mitosis and meiosis I?

  1. Crossing over occurs in mitosis but not in meiosis I.
  2. Mitosis produces haploid cells while meiosis I produces diploid cells.
  3. Sister chromatids separate in meiosis I but not in mitosis.
  4. Homologous chromosomes pair and separate in meiosis I but not in mitosis. Correct answer.

Explanation

In meiosis I, homologous chromosomes synapse and are separated into two cells, reducing chromosome number. Mitosis separates sister chromatids and maintains the diploid number.

Question 19Biology

A population of bacteria is exposed to an antibiotic, and a small number survive and reproduce. Which statement best explains this outcome?

  1. Some bacteria already carried resistance alleles before exposure. Correct answer.
  2. The antibiotic was ineffective because bacteria are eukaryotes.
  3. The antibiotic caused mutations that created resistance.
  4. The bacteria learned to resist the antibiotic during exposure.

Explanation

Antibiotic resistance arises from pre-existing genetic variation; the antibiotic selects for resistant individuals already present in the population. This is directional selection acting on existing alleles.

Question 20Biology

Which of the following best describes the function of the sodium-potassium pump in a neuron at rest?

  1. It moves sodium and potassium down their concentration gradients.
  2. It releases neurotransmitters at the synaptic cleft.
  3. It generates action potentials by opening voltage-gated channels.
  4. It uses ATP to move three sodium ions out and two potassium ions in. Correct answer.

Explanation

The Na+/K+ ATPase hydrolyzes ATP to export three sodium ions and import two potassium ions, maintaining the electrochemical gradients that underlie the resting membrane potential.

Question 21Biology

A scientist wants to determine whether a newly discovered organism is a prokaryote or a eukaryote. Which observation would most strongly support a eukaryotic classification?

  1. Presence of ribosomes
  2. Presence of a plasma membrane
  3. Presence of a cell wall
  4. Presence of membrane-bound organelles Correct answer.

Explanation

Membrane-bound organelles, including a nucleus, are a defining feature of eukaryotic cells. Prokaryotes lack these structures, though they share ribosomes and a plasma membrane with eukaryotes.

Question 22Biology

In an ecosystem, energy is lost at each trophic level primarily because of which process?

  1. Decomposition by bacteria
  2. Nitrogen fixation in soil
  3. Photosynthesis in producers
  4. Respiration and heat loss during metabolism Correct answer.

Explanation

Organisms use much of the energy they assimilate for metabolism, and respiration releases energy as heat that cannot be passed to the next trophic level. This limits the efficiency of energy transfer, typically to about ten percent.

Question 23Biology

Which of the following best explains why a small population is more vulnerable to genetic drift than a large population?

  1. Small populations have higher mutation rates.
  2. Natural selection acts more strongly in small populations.
  3. Random changes in allele frequencies have a larger effect when few individuals contribute. Correct answer.
  4. Small populations always experience gene flow.

Explanation

Genetic drift is sampling error in allele frequencies across generations, and its effect is greater when population size is small because each individual represents a larger fraction of the gene pool.

Question 24Biology

A plant is placed in a sealed chamber and exposed to light. Over time, the carbon dioxide concentration in the chamber decreases. Which process best explains this observation?

  1. Cellular respiration releasing carbon dioxide
  2. Transpiration releasing water vapor
  3. Photorespiration producing carbon dioxide
  4. Photosynthesis consuming carbon dioxide Correct answer.

Explanation

In the light, photosynthesis fixes carbon dioxide into organic molecules, reducing its concentration in the chamber when the rate of photosynthesis exceeds respiration. This net uptake explains the decline.

Question 25Biology

A geneticist crosses two individuals and observes a 1:2:1 phenotypic ratio in the offspring for a single trait. Which pattern of inheritance is most consistent with this result?

  1. Complete dominance
  2. Incomplete dominance Correct answer.
  3. Codominance with two alleles
  4. Sex-linked recessive

Explanation

Incomplete dominance produces an intermediate phenotype in heterozygotes, yielding a 1:2:1 ratio of the two parental phenotypes and the intermediate. Complete dominance would give a 3:1 ratio.

Question 26Biology

A cell biologist treats a culture of human cells with a drug that binds to the hydrophobic core of the phospholipid bilayer and increases membrane fluidity. Which membrane component is most directly affected by this drug?

  1. The peripheral proteins on the cytoplasmic surface
  2. The carbohydrate chains of glycoproteins
  3. The fatty acid tails of membrane phospholipids Correct answer.
  4. The ribosomal subunits attached to the rough ER

Explanation

Membrane fluidity depends chiefly on the interactions among the hydrophobic fatty acid tails in the bilayer interior, so a drug partitioning into that region alters tail packing. Peripheral proteins, glycoprotein carbohydrates, and ribosomes sit at or beyond the membrane surfaces rather than in the hydrophobic core.

Question 27Biology

During which phase of the cell cycle does DNA replication occur in a typical eukaryotic somatic cell?

  1. M phase
  2. G1 phase
  3. S phase Correct answer.
  4. G2 phase

Explanation

Chromosomal DNA is duplicated during S phase (synthesis), which lies between G1 and G2 in interphase. G1 is a growth phase before replication, G2 follows replication, and M phase is when the duplicated chromosomes are segregated and the cell divides.

Question 28Biology

A mutation changes a single base in a gene's promoter region so that RNA polymerase can no longer bind efficiently. Which outcome is most likely?

  1. Translation of that mRNA accelerates
  2. The mRNA gains an extra intron
  3. The genetic code of the organism changes
  4. Transcription of that gene decreases Correct answer.

Explanation

Promoters are binding sites that recruit RNA polymerase to initiate transcription, so disrupting the promoter reduces transcription initiation. The genetic code itself is universal and unchanged, and intron splicing occurs on the transcript after transcription rather than being caused by promoter mutations.

Question 29Biology

In a cross between a homozygous dominant tall pea plant and a homozygous recessive short pea plant, all F1 offspring are tall. When the F1 plants are crossed, what phenotypic ratio is expected in the F2 generation?

  1. 3 tall : 1 short Correct answer.
  2. 1 tall : 2 intermediate : 1 short
  3. 9 tall : 3 short
  4. 1 tall : 1 short

Explanation

The F1 plants are heterozygous, and a monohybrid cross of two heterozygotes yields a 3:1 phenotypic ratio when the dominant allele fully masks the recessive allele. The 1:1 ratio would require a testcross, and the 9:3 ratio involves two independently assorting genes.

Question 30Biology

Which process produces genetically diverse haploid cells during meiosis?

  1. Cytokinesis following telophase II
  2. Crossing over and independent assortment in meiosis I Correct answer.
  3. Formation of the synaptonemal complex alone
  4. DNA replication during S phase

Explanation

Crossing over between homologous chromatids and the independent orientation of homolog pairs at metaphase I both reshuffle alleles, generating genetic variation in the haploid products. DNA replication copies DNA faithfully, and cytokinesis simply partitions the already-divided contents.

Question 31Biology

A patient's blood work shows abnormally low plasma protein levels. Which change in capillary exchange is most directly expected?

  1. Increased diffusion of oxygen into tissues
  2. Greater active transport of glucose into cells
  3. Reduced osmotic reabsorption of fluid into capillaries Correct answer.
  4. Faster conduction of nerve impulses

Explanation

Plasma proteins, especially albumin, generate the colloid osmotic pressure that draws fluid back into capillaries. Lower protein levels reduce this inward pull, favoring fluid movement into the interstitial space. Oxygen diffusion and glucose transport depend on concentration gradients and transporters, not on plasma protein osmotic pressure.

Question 32Biology

Which type of muscle tissue is characterized by striated fibers, intercalated discs, and involuntary control?

  1. Smooth muscle
  2. Skeletal muscle
  3. Connective tissue
  4. Cardiac muscle Correct answer.

Explanation

Cardiac muscle is striated like skeletal muscle but is involuntary and has intercalated discs with gap junctions that coordinate contraction. Skeletal muscle is striated but voluntary, and smooth muscle is involuntary but not striated.

Question 33Biology

A student places an onion cell in a hypertonic solution. What will most likely happen to the cell?

  1. Solutes move into the cell until concentrations equalize
  2. Water enters and the cell bursts
  3. Water leaves the cell and the protoplast shrinks away from the wall Correct answer.
  4. The cell wall dissolves and the cell lyses

Explanation

In a hypertonic solution the external solute concentration is higher, so water exits the cell by osmosis. In plant cells with rigid walls this produces plasmolysis, in which the protoplast shrinks away from the cell wall rather than the cell bursting.

Question 34Biology

Which statement correctly describes the relationship between photosynthesis and cellular respiration in a plant cell?

  1. Photosynthesis occurs only at night and respiration only during the day
  2. Both processes release carbon dioxide as a net product
  3. Respiration produces glucose and oxygen for photosynthesis
  4. Photosynthesis produces organic molecules and oxygen, which respiration can then use Correct answer.

Explanation

Photosynthesis uses light energy to fix carbon dioxide into organic molecules and releases oxygen, and respiration oxidizes those organic molecules using oxygen to release energy. The two processes are complementary rather than producing each other's reactants in reverse.

Question 35Biology

A researcher measures enzyme activity across a range of temperatures and finds a sharp decline above 45 degrees Celsius. Which explanation best accounts for this decline?

  1. The activation energy of the reaction increases
  2. The substrate concentration decreases at higher temperatures
  3. The enzyme begins to synthesize more product
  4. The enzyme's tertiary structure is disrupted, reducing substrate binding Correct answer.

Explanation

High temperatures break the noncovalent interactions that maintain an enzyme's three-dimensional shape, denaturing the active site so substrate binding and catalysis decline. Substrate concentration and activation energy are not directly altered by heating the enzyme itself.

Question 36Biology

A cell is placed in a solution and begins to swell. Which property of the solution best explains this observation?

  1. It is hypertonic relative to the cell
  2. It is hypotonic relative to the cell Correct answer.
  3. It contains no water
  4. It is isotonic relative to the cell

Explanation

In a hypotonic solution the solute concentration outside is lower than inside the cell, so water moves inward by osmosis and the cell swells. Hypertonic solutions draw water out, and isotonic solutions cause no net water movement.

Question 37Biology

Which of the following best describes the role of tRNA in translation?

  1. It carries specific amino acids and pairs its anticodon with mRNA codons Correct answer.
  2. It copies the DNA template into mRNA
  3. It forms the structural core of the ribosome
  4. It removes introns from the pre-mRNA

Explanation

Each tRNA is charged with a particular amino acid and has an anticodon that base-pairs with the complementary codon on mRNA, positioning amino acids for peptide bond formation. Ribosomal RNA forms the ribosome core, RNA polymerase synthesizes mRNA, and spliceosomes remove introns.

Question 38Biology

A population of insects colonizes a new island with a small number of founders. Many generations later, the island population's allele frequencies differ markedly from the source population. Which mechanism most likely produced this difference?

  1. Directional selection for larger body size
  2. Gene flow from the mainland
  3. Assortative mating within the island population
  4. The founder effect Correct answer.

Explanation

When a small group establishes a new population, it carries only a subset of the source gene pool, so allele frequencies can differ by chance, a phenomenon called the founder effect. Selection, gene flow, and nonrandom mating could also change frequencies but are not implied by the founding scenario alone.

Question 39Biology

In a Hardy-Weinberg population, the frequency of the recessive allele is 0.2. What is the expected frequency of heterozygous individuals?

  1. 0.32 Correct answer.
  2. 0.64
  3. 0.04
  4. 0.16

Explanation

If q equals 0.2, then p equals 0.8, and the heterozygote frequency 2pq equals 2 times 0.8 times 0.2, which is 0.32. The value 0.04 is q squared and 0.64 is p squared.

Question 40Biology

Which evidence would most strongly support the hypothesis that two living populations belong to separate biological species?

  1. They interbreed in the laboratory but produce sterile offspring Correct answer.
  2. They share a recent common ancestor
  3. They occupy different habitats on the same continent
  4. They have different coloration patterns

Explanation

Under the biological species concept, members of a species interbreed to produce fertile offspring; viable but sterile hybrids indicate reproductive isolation and separate species. Habitat differences, coloration, and shared ancestry alone do not establish reproductive isolation.

Question 41Biology

A phylogenetic tree groups birds and crocodilians as the closest living relatives. Which line of evidence most directly supports this grouping?

  1. Shared derived anatomical and molecular characters Correct answer.
  2. Similar average lifespan
  3. Occupation of the same geographic region
  4. Similar body size among the groups

Explanation

Phylogenies are built from shared derived characters, including anatomical features and molecular sequence data, that reflect common ancestry. Body size, geography, and lifespan are convergent or ecological traits that do not reliably indicate relatedness.

Question 42Biology

A new antibiotic is tested against a bacterial strain that lacks a cell wall. Which antibiotic would be least effective against this strain?

  1. An antibiotic that inhibits DNA gyrase
  2. An antibiotic that blocks the 50S ribosomal subunit
  3. An antibiotic that disrupts the plasma membrane
  4. Penicillin, which blocks peptidoglycan cross-linking Correct answer.

Explanation

Penicillin acts on peptidoglycan synthesis, so a strain that lacks a cell wall offers no target for the drug. Inhibitors of DNA gyrase, ribosome function, or membrane integrity act on structures the cell still possesses.

Question 43Biology

Which feature distinguishes archaea from bacteria at the molecular level?

  1. Archaea have ether-linked membrane lipids and histones in some species Correct answer.
  2. Archaea lack a plasma membrane
  3. Archaea lack ribosomes entirely
  4. Archaea use RNA as their genetic material

Explanation

Archaeal membrane lipids use ether linkages and branched isoprenoid chains, and some archaea possess histone-like proteins that compact DNA, features that distinguish them from bacteria. Archaea still have ribosomes, DNA genomes, and plasma membranes.

Question 44Biology

A plant is grown in soil lacking nitrogen but supplied with ample light and water. Which process will be most directly limited?

  1. Absorption of light by chlorophyll
  2. Synthesis of amino acids and proteins Correct answer.
  3. Opening of stomata in response to light
  4. Movement of water through xylem

Explanation

Nitrogen is an essential component of amino acids, proteins, and nucleic acids, so its deficiency most directly limits protein synthesis. Light absorption, xylem water movement, and stomatal opening depend mainly on pigments, water potential, and guard cell signaling rather than on nitrogen supply.

Question 45Biology

Which hormone is primarily responsible for the fight-or-flight response, including increased heart rate and elevated blood glucose?

  1. Epinephrine Correct answer.
  2. Calcitonin
  3. Thyroxine
  4. Insulin

Explanation

Epinephrine, released from the adrenal medulla, raises heart rate, dilates airways, and promotes glycogen breakdown to increase blood glucose during acute stress. Insulin lowers blood glucose, thyroxine regulates metabolism over longer timescales, and calcitonin lowers blood calcium.

Question 46Biology

A student examines a food web and removes a top predator. Which prediction is most consistent with ecological theory?

  1. The ecosystem will lose all of its decomposers
  2. The primary producers will immediately go extinct
  3. Populations of intermediate consumers may increase and alter lower trophic levels Correct answer.
  4. Energy transfer efficiency between trophic levels will rise above 50 percent

Explanation

Removing a top predator can release intermediate consumers from predation, causing a trophic cascade in which their numbers grow and their prey decline. Energy transfer efficiency and decomposer presence are not directly determined by removing one predator.

Question 47Biology

A population of mice experiences a severe bottleneck. Which consequence is most likely over the next several generations?

  1. Elimination of all recessive alleles
  2. Increased genetic variation from mutation
  3. Reduced genetic variation and increased influence of genetic drift Correct answer.
  4. Immediate speciation into two new species

Explanation

A bottleneck reduces the number of breeding individuals, so many alleles are lost and the surviving gene pool is a small, possibly unrepresentative sample. Drift then has a larger effect because random sampling error is greater in small populations, and mutation cannot quickly restore lost variation.

Question 48Biology

A researcher finds that a single gene influences both wing shape and mating behavior in a fruit fly. Which phenomenon does this illustrate?

  1. Epistasis
  2. Codominance
  3. Polygenic inheritance
  4. Pleiotropy Correct answer.

Explanation

Pleiotropy occurs when one gene affects multiple phenotypic traits, as when a single locus influences both wing morphology and behavior. Codominance concerns allele expression in heterozygotes, epistasis involves one gene masking another, and polygenic inheritance involves many genes affecting one trait.

Question 49Biology

Which technique would a molecular biologist use to separate DNA fragments of different sizes after restriction digestion?

  1. Southern blotting alone
  2. Polymerase chain reaction
  3. Gel electrophoresis Correct answer.
  4. Sanger sequencing

Explanation

Gel electrophoresis drives negatively charged DNA through a gel matrix, so smaller fragments migrate farther and separate by size. PCR amplifies DNA, Sanger sequencing determines nucleotide order, and a Southern blot detects specific sequences after transfer rather than primarily separating fragments by size.

Question 50Biology

A cell is treated with a drug that prevents the formation of the mitotic spindle. At which stage will the cell most likely arrest?

  1. Metaphase Correct answer.
  2. Prophase I of meiosis
  3. Telophase
  4. G1 phase

Explanation

Spindle microtubules attach to kinetochores and align chromosomes at the metaphase plate; without a functional spindle the spindle assembly checkpoint arrests the cell before anaphase. G1 and telophase occur outside the spindle-dependent alignment step, and meiosis I is not the relevant division for a mitotic cell.