Cumulative exam

1.
Q: What is Science and Biology?
A: Science is a method of understanding the natural world through observation and experimentation. Biology is the scientific study of life and living organisms.

2.
Q: What is the scientific method, its steps, and a controlled experiment?
A: Steps: Observation → Question → Hypothesis → Experiment → Results → Conclusion. A controlled experiment tests one variable at a time with control and experimental groups.

3.
Q: What is a hypothesis and how is it different from a scientific theory?
A: A hypothesis is a testable prediction. A theory is a well-supported explanation backed by evidence.

4.
Q: What is the hierarchical organization of living things?
A: Atom → Molecule → Organelle → Cell → Tissue → Organ → Organ System → Organism → Population → Community → Ecosystem → Biosphere.

5.
Q: What are the characteristics of life?
A: Made of cells, use energy, grow and develop, reproduce, respond to stimuli, maintain homeostasis, evolve over time.

6.
Q: Structure of an atom and differences among particles?
A: Atoms consist of protons (+), neutrons (0), and electrons (–). Protons/neutrons in nucleus; electrons orbit. Elements are made of atoms; molecules are bonded atoms.

7.
Q: What is the octet rule and atomic reactivity?
A: Atoms react to fill their outer electron shell (usually 8 electrons), becoming stable.

8.
Q: Difference between atomic number and atomic weight?
A: Atomic number = protons; atomic weight = protons + neutrons.

9.
Q: Covalent vs. ionic vs. hydrogen bonds?
A: Covalent: share electrons. Ionic: transfer electrons. Hydrogen: weak attraction between polar molecules.

10.
Q: Why is water important to life?
A: Solvent, cohesive/adhesive, temperature buffer, participates in chemical reactions (e.g., hydrolysis).

11.
Q: What are organic compounds and carbon’s role?
A: Organic compounds contain carbon. Carbon’s 4 valence electrons make it versatile in bonding.

12.
Q: Monomers and polymers of macromolecules?
A: Carbs: monosaccharides → polysaccharides; Proteins: amino acids → polypeptides; Nucleic acids: nucleotides → DNA/RNA.

13.
Q: Hydrolysis vs. dehydration synthesis?
A: Hydrolysis adds water to break bonds; dehydration synthesis removes water to form bonds.

14.
Q: Structure/functions of macromolecules?
A: Carbs: energy; Lipids: insulation, membranes; Proteins: structure, enzymes; Nucleic acids: genetic info.

15.
Q: Amino acid structure and protein folding?
A: Amino acids have an amino group, carboxyl group, R-group. Folding determines function. Denaturation = loss of shape and function.

16.
Q: What is the cell theory?
A: All organisms are made of cells; the cell is the basic unit of life; all cells come from pre-existing cells.

17.
Q: Prokaryotic vs. eukaryotic cells; plant vs. animal?
A: Prokaryotes: no nucleus. Eukaryotes: have organelles. Plants have cell walls and chloroplasts; animals do not.

18.
Q: What is the endosymbiotic theory?
A: Mitochondria and chloroplasts were once free-living bacteria engulfed by ancestral cells.

19.
Q: Organelles and their functions?
A: Nucleus: DNA storage; Mitochondria: ATP; Ribosomes: protein synthesis; ER: transport; Golgi: packaging.

20.
Q: Plasma membrane and Fluid Mosaic Model?
A: Flexible bilayer of phospholipids with embedded proteins; dynamic and semi-permeable.

21.
Q: What is the difference between diffusion & osmosis; active and passive transport, simple and facilitated diffusion?
A: Diffusion: movement from high to low concentration. Osmosis: diffusion of water. Passive: no energy. Active: uses energy. Facilitated: uses proteins to help molecules cross.

22.
Q: What do hypertonic, hypotonic, and isotonic mean?
A: Hypertonic: water leaves cell (shrinks). Hypotonic: water enters cell (swells). Isotonic: no net movement.

23.
Q: Difference between plasmolysis, lysis, crenation, and turgidity?
A: Plasmolysis: plant cells shrink. Lysis: animal cells burst. Crenation: animal cells shrink. Turgidity: plant cells full of water, firm.

24.
Q: What is energy and what are its forms?
A: Capacity to do work. Forms: kinetic, potential, chemical, thermal, etc.

25.
Q: What are the Laws of Thermodynamics?
A: 1st: Energy can't be created/destroyed. 2nd: Energy transformations increase entropy.

26.
Q: What is the ATP/ADP cycle?
A: ATP stores energy; when phosphate is removed (→ ADP), energy is released.

27.
Q: What are coupled reactions?
A: Pairing an exergonic reaction (releases energy) with an endergonic one (requires energy).

28.
Q: Exergonic vs. endergonic reactions?
A: Exergonic: release energy (e.g., respiration). Endergonic: absorb energy (e.g., photosynthesis).

29.
Q: What are enzymes and what affects them?
A: Proteins that speed up reactions. Affected by pH, temperature, inhibitors (competitive/non-competitive), and substrate concentration.

30.
Q: What are redox reactions and roles of NAD, NADP, FAD?
A: Redox = transfer of electrons. These carriers accept and donate electrons in respiration/photosynthesis.

31.
Q: Overall equations for respiration and fermentation?
A:

• Aerobic: C₆H₁₂O₆ + O₂ → CO₂ + H₂O + ATP
  
  

• Alcoholic: Glucose → Ethanol + CO₂ + ATP
  
  

• Lactic: Glucose → Lactic acid + ATP
  
  

32.
Q: Final electron acceptors and ATP yields?
A:

• Aerobic: O₂; ~36–38 ATP
  
  

• Anaerobic: other inorganic molecules; fewer ATP
  
  

• Fermentation: organic molecules; 2 ATP
  
  

33.
Q: Stages of aerobic respiration and products?
A:

• Glycolysis: 2 ATP, 2 NADH
  
  

• Transition: 2 NADH
  
  

• Krebs: 2 ATP, 6 NADH, 2 FADH₂
  
  

• ETC: ~32 ATP, H₂O
  
  

34.
Q: Oxygen use and location of stages?
A: Glycolysis in cytoplasm (no O₂). Others in mitochondria; ETC needs O₂.

35.
Q: Ultimate energy source for life?
A: The Sun.

36.
Q: Leaf/chloroplast structure and water-loss adaptations?
A: Cuticle, stomata, guard cells prevent water loss. Chloroplasts contain thylakoids and stroma.

37.
Q: Advantages of green plants?
A: Provide oxygen, food, absorb CO₂, base of food chains.

38.
Q: Main requirements for photosynthesis?
A: Sunlight, CO₂, water, chlorophyll.

39.
Q: Photosynthesis equation?
A: 6CO₂ + 6H₂O + sunlight → C₆H₁₂O₆ + 6O₂

40.
Q: Light-dependent vs. Calvin cycle products?
A: Light-dependent: ATP, NADPH, O₂
Calvin: Glucose (from CO₂, ATP, NADPH)

41.
Q: When/how is oxygen generated in photosynthesis?
A: During light-dependent reactions when water is split (photolysis).

42.
Q: Photosynthesis vs. respiration?
A: Photosynthesis: endergonic, stores energy. Respiration: exergonic, releases energy.

43.
Q: What are the stages of the Cell Cycle?
A: Interphase (G₁, S, G₂), Mitosis (Prophase → Telophase), Cytokinesis.

44.
Q: What is binary fission and where does it occur?
A: Asexual reproduction in prokaryotes where a cell divides into two identical cells.

45.
Q: What are the stages of mitosis and when does it occur?
A:

• Prophase: chromosomes condense, spindle forms
  
  

• Metaphase: chromosomes align
  
  

• Anaphase: sister chromatids separate
  
  

• Telophase: nuclei reform
  Occurs in somatic (body) cells for growth/repair.
  
  

46.
Q: How does mitosis differ in plant and animal cells?
A: Plants form a cell plate; animals form a cleavage furrow.

47.
Q: Steps of meiosis and what occurs?
A:

• Meiosis I: homologous chromosomes separate
  
  

• Meiosis II: sister chromatids separate
  Creates 4 non-identical haploid gametes.
  
  

48.
Q: What is crossing over and independent assortment?
A: Crossing over: homologous chromosomes exchange genes in Prophase I.
Independent assortment: random distribution of homologs in Metaphase I.

49.
Q: Differences between diploid/haploid, gamete/somatic, mitosis/meiosis?
A:

• Diploid: 2n, Haploid: n
  
  

• Gamete: reproductive, Somatic: body
  
  

• Mitosis: 2 identical cells, Meiosis: 4 unique cells
  
  

50.
Q: Dominant vs. recessive, homozygous vs. heterozygous, gene vs. allele, phenotype vs. genotype?
A:

• Dominant: shows if present
  
  

• Recessive: shows if homozygous
  
  

• Homozygous: same alleles; Heterozygous: different
  
  

• Gene: DNA segment
  
  

• Allele: gene variant
  
  

• Genotype: genetic makeup; Phenotype: physical traits
  
  

51.
Q: Phenotypic ratios in F₂ monohybrid and dihybrid crosses?
A:

• Monohybrid: 3:1
  
  

• Dihybrid: 9:3:3:1
  
  

52.
Q: Laws of Segregation and Independent Assortment?
A:

• Segregation: alleles separate during gamete formation
  
  

• Independent Assortment: genes on different chromosomes assort independently
  
  

53.
Q: What is incomplete dominance, codominance, polygenic inheritance?
A:

• Incomplete: blend (e.g., pink flowers)
  
  

• Codominance: both alleles expressed (AB blood)
  
  

• Polygenic: many genes affect trait (height)
  
  

54.
Q: How are human blood groups inherited?
A: By multiple alleles (A, B, O) with codominance (A and B both expressed in AB).

55.
Q: Classes of genetic diseases and inheritance patterns?
A:

• Autosomal dominant: only 1 copy needed (e.g., Huntington's)
  
  

• Autosomal recessive: both copies needed (e.g., cystic fibrosis)
  
  

• X-linked recessive: males affected more (e.g., hemophilia)
  
  

• Mitochondrial: from mother only
  
  

56.
Q: Correct notation of genetic disorders?
A: Dominant: Aa or AA
Recessive: aa
X-linked: XᴴXʰ, XʰY
Mitochondrial: all offspring of affected female inherit

57.
Q: How to solve genetic problems?
A: Use Punnett squares to predict genotype and phenotype ratios.

58.
Q: How to interpret pedigrees and give genotypes?
A: Circles = females, Squares = males; shaded = affected. Determine inheritance pattern and infer genotypes.

59.
Q: What is chromosomal nondisjunction?
A: Failure of chromosomes to separate; causes conditions like Down syndrome (trisomy 21), Turner (XO), Klinefelter (XXY).

60.
Q: What is the structure of DNA and how does replication work?
A: Double helix of nucleotides (A-T, C-G). Replication is semi-conservative: each new DNA has one old and one new strand.

61.
Q: What happens during transcription and translation?
A:

• Transcription: DNA → mRNA (in nucleus)
  
  

• Translation: mRNA → protein (at ribosome, using tRNA and rRNA)
  
  

62.
Q: Why is gene regulation needed and how does it happen?
A: Ensures correct gene expression.

• Prokaryotes: operons
  
  

• Eukaryotes: transcription factors, enhancers/silencers
  
  

63.
Q: What are restriction enzymes, cloning, DNA fingerprinting, PCR?
A:

• Restriction enzymes: cut DNA
  
  

• Cloning: copying genes/cells
  
  

• DNA fingerprinting: ID individuals
  
  

• PCR: amplifies DNA for testing