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WorksheetsBiological Science Final Examination Fall 2025
Total questions: 120
Worksheet time: 3600secs
What is the overall chemical equation for photosynthesis?
(a)
Where do the light-dependent reactions of photosynthesis occur within the chloroplast?
(a)
What are the two main stages of photosynthesis and where does each occur?
(a)
What is the primary function of chlorophyll a in photosynthesis?
(a)
Explain the difference between chlorophyll a and chlorophyll b in terms of their absorption spectra.
(a)
What wavelengths of light are most effectively absorbed by chlorophyll?
(a)
Describe the structure of a chloroplast, including the thylakoid membrane, stroma, and grana.
(a)
What is a photosystem and what are the two types found in plants?
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Explain the role of Photosystem II in the light-dependent reactions.
(a)
What is photolysis and why is it important in photosynthesis?
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Describe the electron transport chain in the thylakoid membrane.
(a)
How is the chemiosmotic gradient established during the light-dependent reactions?
(a)
What is the role of ATP synthase in photosynthesis?
(a)
What are the products of the light-dependent reactions?
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Describe the Calvin cycle and where it takes place.
(a)
What is the role of RuBisCO in the Calvin cycle?
(a)
What is carbon fixation and which molecule accepts CO2 in this process?
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How many turns of the Calvin cycle are required to produce one glucose molecule?
(a)
What is photorespiration and under what conditions does it occur?
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Compare and contrast C3, C4, and CAM photosynthesis.
(a)
What are stomata and how do they regulate gas exchange?
(a)
How do C4 plants minimize photorespiration?
(a)
When do CAM plants open their stomata and why is this adaptive?
(a)
What environmental factors affect the rate of photosynthesis?
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Explain how photosynthesis and cellular respiration are complementary processes.
(a)
Which statement best explains how epithelial tissue supports homeostasis at organ surfaces?
It secretes hormones into blood for rapid signaling
It forms protective barriers that regulate exchange
It stores minerals that buffer blood pH
It generates strong contractions for body movement
A patient with reduced tendon flexibility likely has changes in which connective tissue component?
Actin-myosin filaments in cardiac muscle
Myelin sheaths around peripheral neurons
Elastic fibers within dense regular tissue
Keratin filaments within stratified epidermis
Choose the best example of negative feedback in human physiology.
Platelet amplification during clot formation
Oxytocin-enhanced uterine contractions during labor
Insulin secretion lowering elevated blood glucose
Estrogen surge preceding ovulation timing
Which scenario illustrates a positive feedback loop?
Thermoregulation stabilizing core temperature
Baroreceptor reflex reducing high blood pressure
Renal filtration adjusting to plasma osmolarity
Uterine contractions intensifying via oxytocin
Which statement best distinguishes neurons from neuroglia?
Neurons mainly secrete hormones; glia conduct impulses
Neurons form myelin; glia release neurotransmitters
Neurons divide frequently; glia never proliferate
Neurons primarily transmit electrical signals; glia support
Which tissue type is specialized for force generation through actin–myosin interactions?
Nervous tissue with synaptic vesicles
Connective tissue with collagen bundles
Muscle tissue with contractile filaments
Epithelial tissue with tight junction networks
Which best describes the integumentary system’s primary functions?
Hormone secretion and calcium homeostasis
Gas exchange and acid–base regulation
Protection, thermoregulation, and sensory input
Nutrient absorption and peristalsis control
Arrange the skin layers from superficial to deep.
(a)
Which bone tissue type resists compression with osteons and lamellae?
Spongy bone with trabecular spaces
Elastic cartilage with flexible fibers
Compact bone with organized osteons
Dense irregular connective tissue
What structure connects muscle to bone in the skeletal system?
Aponeurosis composed of reticular fibers
Periosteum composed of hyaline cartilage
Tendon composed of dense regular collagen
Ligament composed of elastic bundles
Which best describes the heart’s four chambers in blood flow sequence starting at systemic venous return?
Left atrium → left ventricle → aorta → body
Left ventricle → left atrium → lungs → right atrium
Right atrium → right ventricle → lungs → left atrium
Right ventricle → right atrium → lungs → left ventricle
Trace the path of a red blood cell from the right ventricle to systemic tissues.
(a)
Which function is primarily carried out by the lymphatic system?
Gas exchange between alveoli and blood
Return of interstitial fluid and immune surveillance
Filtration of plasma and acid–base control
Mechanical digestion and nutrient absorption
Which components form the respiratory conducting zone?
Pharynx, alveoli, and pleural membranes
Larynx, alveoli, and pulmonary capillaries
Trachea, bronchi, and terminal bronchioles
Alveolar sacs and respiratory bronchioles
During inspiration, what is the primary role of the diaphragm?
It contracts to increase thoracic volume
It relaxes to lower intrapleural volume
It relaxes to increase thoracic pressure
It contracts to decrease lung compliance
Place the major digestive organs in order for food passage from mouth to anus.
(a)
Which statement best describes the urinary system’s key function?
Coordinates voluntary movement via motor circuits
Generates immune memory via antigen presentation
Maintains fluid and electrolyte balance via filtration
Exchanges gases via alveolar diffusion
Match each endocrine gland with a hormone it produces.
Pituitary → melatonin; Thyroid → prolactin; Adrenal → aldosterone
Pituitary → cortisol; Thyroid → insulin; Adrenal → thyroxine
Pituitary → ADH; Thyroid → T3/T4; Adrenal → epinephrine
Pituitary → glucagon; Thyroid → estrogen; Adrenal → calcitonin
How does nervous signaling differ from endocrine signaling in speed and duration?
Faster onset, briefer duration than hormones
Slower onset, briefer duration than hormones
Similar onset and duration across both systems
Faster onset, longer duration than hormones
Which event best characterizes the S phase of the cell cycle?
Spindle fibers assemble from centrosomes
DNA replication produces sister chromatids
Chromatin condenses into visible chromosomes
Cells grow and synthesize cytoplasmic proteins
During G1, a typical mammalian cell primarily
duplicates its genome for mitosis
grows and performs metabolic functions
completes cytokinesis and separates
checks spindle–kinetochore attachment
Which checkpoint prevents cells with damaged DNA from entering S phase?
G0 checkpoint
Metaphase checkpoint
G1 checkpoint
G2 checkpoint
Sister chromatids are held together most directly by the
centromere and cohesin complexes
telomere-binding shelterin
nuclear lamina proteins
microtubules of the spindle
Which description distinguishes chromatin from chromosomes most accurately?
Chromatin is mitochondrial DNA; chromosomes are nuclear
Chromatin is circular DNA; chromosomes are linear RNA
Chromatin is dispersed DNA-protein; chromosomes are condensed
Chromatin is RNA-protein complexes; chromosomes are DNA
What is the primary role of centromeres during mitosis?
Signal the metaphase-to-anaphase transition
Attach spindle microtubules to kinetochores
Anchor the nuclear envelope to lamina
Initiate DNA replication in S phase
Which sequence correctly lists mitosis stages in order?
Prophase → Metaphase → Anaphase → Telophase
Prophase → Telophase → Metaphase → Anaphase
Metaphase → Prophase → Anaphase → Telophase
Anaphase → Metaphase → Prophase → Telophase
During prophase of mitosis, cells typically
align chromosomes at equator
condense chromatin and form spindle
separate sister chromatids fully
complete cytokinesis and split
Which event defines metaphase most precisely?
Cytokinesis divides cytoplasm
Cohesin is loaded onto centromeres
Chromosomes align on metaphase plate
Nuclear envelope reforms at poles
Anaphase begins when
cyclins are degraded by lysosomes
cohesin binds kinetochores tightly
securin is degraded, releasing separase
microtubules depolymerize at minus ends
Telophase is characterized by
nuclear envelope breakdown and spindle formation
chromosome alignment at the equatorial plane
chromosomes decondense and nuclei re-form
cleavage furrow formation by myosin II
In animal cells, cytokinesis typically proceeds by
fusion of sister chromatids at centromeres
binary fission of nucleoids
cell plate assembly from vesicles
contractile ring forming a cleavage furrow
Compared with mitosis in animal cells, cytokinesis in plant cells involves
breakdown of rigid cell plate structures
myosin-driven constriction of membrane
formation of a cell plate from Golgi vesicles
use of centrosomes to pinch cytoplasm
Which process in prokaryotes functionally replaces eukaryotic mitosis?
Apoptosis
Binary fission
Endocytosis
Meiosis I
Cyclins and CDKs regulate the cell cycle primarily by
blocking microtubule polymerization
phosphorylating specific substrates
degrading DNA via nucleases
activating G protein signaling
Which tumor suppressor protein promotes cell cycle arrest or apoptosis in response to DNA damage?
Myc
p53
Cyclin D
Ras
Apoptosis contributes to cell cycle control by
driving uncontrolled proliferation
eliminating irreparably damaged cells
fusing sister chromatids permanently
inhibiting checkpoint signaling
Metastasis refers to
cellular senescence after DNA damage
angiogenesis within the tumor mass
localized growth without invasion
spread of cancer cells to distant sites
Growth factors influence cell division mainly by
crosslinking intermediate filaments
triggering receptor-mediated signaling cascades
directly replicating nuclear DNA
forming kinetochores at centromeres
What is genetics and what did Gregor Mendel contribute to this field?
(a)
Define the terms genotype and phenotype.
(a)
What is the difference between homozygous and heterozygous?
(a)
Explain the difference between dominant and recessive alleles.
(a)
State Mendel's Law of Segregation.
(a)
What is a monohybrid cross?
(a)
If you cross two heterozygous individuals (Aa × Aa), what is the expected phenotypic ratio?
(a)
What is a testcross and why is it useful?
(a)
State Mendel's Law of Independent Assortment.
(a)
What is a dihybrid cross?
(a)
In a dihybrid cross of two heterozygotes (AaBb × AaBb), what is the expected phenotypic ratio?
(a)
What is incomplete dominance? Give an example.
(a)
How does codominance differ from incomplete dominance?
(a)
What is pleiotropy?
(a)
Define epistasis and provide an example.
(a)
What is polygenic inheritance?
(a)
How do environmental factors influence phenotype?
(a)
What is the norm of reaction?
(a)
Explain sex-linked inheritance.
(a)
What is hemophilia and how is it inherited?
(a)
Describe red-green color blindness as an example of X-linked inheritance.
(a)
What is crossing over and when does it occur?
(a)
Why are X-linked recessive disorders more common in males?
Males undergo more meiotic divisions
Males have only one X chromosome
Males have two Y chromosomes
Males express stronger immune responses
What is hemophilia and how is it inherited?
An autosomal dominant clotting defect
A mitochondrial disorder of platelets
An X-linked recessive bleeding disorder
A polygenic trait affecting coagulation
Describe red-green color blindness as an example of X-linked inheritance.
Autosomal dominant vision deficiency
Y-linked recessive trait in males
X-linked trait affecting cone pigments
Mitochondrial mutation in photoreceptors
What are linked genes and why don't they assort independently?
They are affected only by environmental factors
They are on the same chromosome close together
They share identical alleles always
They reside on different chromosomes
What is crossing over and when does it occur?
Exchange of alleles during mitosis
Duplication of DNA in S phase
Reciprocal exchange during prophase I
Random fusion of gametes at fertilization
How did Thomas Hunt Morgan's work with fruit flies support the chromosome theory?
Showed DNA is a protein complex
Linked traits to specific chromosomes
Demonstrated blending inheritance
Proved meiosis occurs in plants only
What are homologous chromosomes?
Chromosomes with identical DNA sequences
Non-sister chromatids in mitosis
Pairs carrying same genes at loci
Duplicated sister chromatids only
How many chromosomes do human somatic cells contain?
(a)
What is a karyotype and what information does it provide?
A protein expression profile
An arranged image of chromosomes
A gene map of linkage distances
A sequence of nucleotides in a gene
Define autosomes and sex chromosomes.
Autosomes exist only in gametes
Autosomes are non-sex chromosomes; sex chromosomes determine sex
Autosomes determine sex only
Sex chromosomes carry no genes
Describe the SRY gene and its role in sex determination.
Regulates meiosis in spermatocytes
Triggers testis development on Y
Encodes enzymes for oogenesis
Controls X-inactivation in females
What is nondisjunction and when can it occur?
Fusion of gametes in fertilization
Breakage of chromosomes during mitosis
Failure of chromosome segregation in meiosis I or II
Premature DNA replication during S phase
What is aneuploidy?
Abnormal number of particular chromosomes
Errors in DNA base pairing only
Presence of extra organelles
Gain or loss of whole sets
What is the difference between monosomy and trisomy?
Both occur only in plants
Monosomy is missing one; trisomy is extra one
Monosomy is extra chromosome; trisomy is missing
Both are extra sets of chromosomes
What causes polyploidy and why is it more common in plants than animals?
Nondisjunction of one chromosome
Errors leading to extra sets; plants tolerate
Point mutations in chloroplast DNA
Selective pressure against meiosis
What are deletions, duplications, inversions, and translocations in terms of chromosomal mutations?
Epigenetic modifications of histones
Changes only in gene expression levels
Structural changes in chromosome segments
Mutations only in mitochondrial DNA
How can chromosomal inversions affect fertility?
Enhance nondisjunction always
Eliminate meiosis completely
Cause abnormal pairing and gametes
Increase recombination uniformly
What is a translocation and how can it lead to genetic disorders?
Movement within same gene; silent always
Exchange between nonhomologous chromosomes; disrupt genes
Duplication within homologous pair; neutral
Transfer to mitochondria; benign effect
Describe the chromosomal abnormality associated with chronic myelogenous leukemia (CML).
Tetraploidy in leukocyte precursors
Reciprocal translocation t(9;22) Philadelphia
Robertsonian fusion of 13 and 14
Deletion of Xp arm region
Why do calico cats exhibit their distinctive coat pattern?
Autosomal dominant pigment gene
X-inactivation creates mosaic expression
Y-linked mosaic expression in females
Mitochondrial pigment gene variation
At what stage of meiosis does crossing over occur and why is it important?
Telophase I; restores diploid number
Anaphase I; prevents nondisjunction
Prophase I; increases genetic diversity
Metaphase II; ensures spindle attachment
What are the three components of a nucleotide?
(a)
Name the four nitrogenous bases found in DNA.
(a)
Which bases pair together in DNA and how many hydrogen bonds form between each pair?
(a)
Describe the antiparallel nature of DNA strands.
(a)
What is DNA replication and why is it described as semiconservative?
(a)
What is the role of DNA helicase in replication?
(a)
What is the function of DNA polymerase?
(a)
What are primers and why are they necessary for DNA replication?
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How does RNA differ from DNA structurally?
(a)
What are the three main types of RNA and their functions?
(a)
What is a promoter region?
(a)
What are the three stages of transcription?
(a)
What is RNA processing in eukaryotes? Include information about the 5' cap, poly-A tail, and splicing.
(a)
Explain the process of translation, including the roles of mRNA, tRNA, and ribosomes.
(a)
