final exam 3

What is Science and Biology?

Science is a method of understanding the natural world. Biology is the study of life and living organisms.

What is the scientific method, its steps, and a controlled experiment?

Observation → Question → Hypothesis → Experiment → Results → Conclusion; Controlled experiments test one variable at a time.

What is a hypothesis and how is it different from a scientific theory?

A hypothesis is a testable prediction; a theory is a well-supported explanation based on evidence.

What are the characteristics of life?

Organization, response to stimuli, homeostasis, metabolism, growth, reproduction, adaptation/evolution.

How are atoms and molecules organized and what are the 3 types of bonds?

Atoms: protons, neutrons, electrons. Molecules: atoms bonded. Bonds: covalent (share), ionic (transfer), hydrogen (weak, between molecules).

What is the structure of water and why is it essential?

Polar molecule with hydrogen bonds. Important for cohesion, temperature stability, and as a solvent.

What are the 4 macromolecules, their monomers, and functions?

Carbs (monosaccharides, energy), Proteins (amino acids, structure/enzymes), Lipids (fatty acids, energy/membranes), Nucleic acids (nucleotides, genetic info).

What is the function of enzymes?

Speed up reactions by lowering activation energy; they are specific and reusable.

What are the main principles of the cell theory?

All living things are made of cells, cells are the basic unit of life, and all cells come from preexisting cells.

How are prokaryotic and eukaryotic cells similar and different?

Both have membranes, DNA, cytoplasm. Eukaryotes have nuclei and organelles; prokaryotes do not.

What are the differences between plant, animal, and bacterial cells?

Plants: cell wall, chloroplasts. Animals: no cell wall. Bacteria: prokaryotic, no nucleus.

What are the functions of the nucleus, mitochondria, chloroplasts, and ribosomes?

Nucleus: stores DNA; Mitochondria: make ATP; Chloroplasts: photosynthesis; Ribosomes: protein synthesis.

What is the structure and function of the cell membrane?

Phospholipid bilayer with proteins. Controls what enters/leaves the cell.

What is homeostasis and how is it maintained?

Maintaining a stable internal environment using feedback loops and transport mechanisms.

What are anabolic and catabolic reactions?

Anabolic: build molecules, use energy. Catabolic: break down molecules, release energy.

What is the difference between diffusion and osmosis?

Diffusion: movement of molecules. Osmosis: diffusion of water across membranes.

What is the difference between active and passive transport?

Passive: no energy needed (diffusion, osmosis). Active: requires energy (pumps, endocytosis).

What is the difference between simple and facilitated diffusion?

Simple: moves directly through membrane. Facilitated: uses proteins to help molecules cross.

What do hypertonic, hypotonic, and isotonic mean?

Hypertonic: water leaves cell (shrinks). Hypotonic: water enters cell (swells). Isotonic: equal movement.

What is plasmolysis, lysis, crenation, and turgidity?

Plasmolysis: plant cells shrink. Lysis: animal cells burst. Crenation: animal cells shrink. Turgidity: plant cells full of water.

What is energy and what are its forms?

Energy is the capacity to do work. Forms: kinetic, potential, chemical, thermal, etc.

What are the Laws of Thermodynamics?

1st: Energy cannot be created/destroyed. 2nd: Energy transfers increase disorder (entropy).

What is the ATP/ADP cycle?

ATP stores energy; releasing a phosphate turns it into ADP and releases energy.

What are coupled reactions?

Reactions that occur together: one releases energy, the other uses it.

What are exergonic and endergonic reactions?

Exergonic: release energy (e.g., respiration). Endergonic: absorb energy (e.g., photosynthesis).

What are enzymes and what affects their function?

Enzymes are proteins that speed up reactions. Affected by pH, temperature, inhibitors, and substrate concentration.

What are redox reactions and the role of NAD, NADP, and FAD?

Redox: electron transfer reactions. NAD/NADP/FAD are electron carriers in respiration/photosynthesis.

What is the overall equation for aerobic respiration and fermentation?

Aerobic: C6H12O6 + O2 → CO2 + H2O + ATP; Fermentation: Glucose → Lactic acid or Ethanol + CO2 + ATP

What are the final electron acceptors and ATP yields in different respiration types?

Aerobic: O2, ~36–38 ATP; Anaerobic: other molecules, fewer ATP; Fermentation: 2 ATP.

What are the stages of aerobic respiration and their products?

Glycolysis: 2 ATP, 2 NADH. Transition: 2 NADH. Krebs: 2 ATP, 6 NADH, 2 FADH2. ETC: ~32 ATP.

Where does each stage of respiration occur and what uses oxygen?

Glycolysis in cytoplasm (no O2), others in mitochondria. ETC uses oxygen.

What is the ultimate energy source for life?

The sun.

What are the structures of leaves and chloroplasts and water conservation methods?

Chloroplasts: thylakoids (light reactions), stroma (Calvin cycle). Leaves: cuticle, guard cells, stomata help conserve water.

Why are green plants essential for life?

They provide oxygen, food, and remove CO2; base of most food chains.

What is required for photosynthesis?

Sunlight, CO2, water, chlorophyll.

What is the overall equation for photosynthesis?

6CO2 + 6H2O + sunlight → C6H12O6 + 6O2

What are the products of the light-dependent and light-independent reactions?

Light-dependent: ATP, NADPH, O2. Calvin cycle: Glucose.

When and how is oxygen generated in photosynthesis?

When water is split during light reactions (photolysis).

How is photosynthesis the reverse of cellular respiration?

Photosynthesis stores energy (endergonic), respiration releases it (exergonic); their equations are reversed.

What are the stages of the cell cycle?

Interphase (G1, S, G2), M phase (mitosis), Cytokinesis.

What is binary fission and where does it occur?

Asexual reproduction in prokaryotes; one cell splits into two.

What are the stages of mitosis and when does it occur?

Prophase, Metaphase, Anaphase, Telophase. Occurs in somatic (body) cells.

How does mitosis differ in plant and animal cells?

Plants form a cell plate; animals form a cleavage furrow.

What are the steps of meiosis and what happens in each?

Meiosis I: homologous chromosomes separate. Meiosis II: sister chromatids separate. Produces 4 unique gametes.

What is crossing over and independent assortment?

Crossing over: exchange of genes (Prophase I). Independent assortment: random alignment (Metaphase I).

What are differences between diploid and haploid, gamete and somatic, mitosis and meiosis?

Diploid: 2 sets, Haploid: 1 set. Gamete: sex cell, Somatic: body cell. Mitosis: identical cells. Meiosis: 4 different gametes.

What is the difference between dominant and recessive, homozygous and heterozygous, gene and allele, phenotype and genotype?

Dominant: always shows. Recessive: needs two copies. Homozygous: same alleles. Heterozygous: different. Gene: DNA segment. Allele: version. Genotype: genes. Phenotype: traits.

What are the expected phenotypic ratios in F2 generation of monohybrid and dihybrid crosses?

Monohybrid: 3:1. Dihybrid: 9:3:3:1.

What are the laws of segregation and independent assortment?

Segregation: alleles separate in meiosis. Independent assortment: genes on different chromosomes assort randomly.

What are incomplete dominance, codominance, and polygenic inheritance?

Incomplete: blend (e.g. pink). Codominance: both show (AB blood). Polygenic: many genes affect trait (height).

How are human blood groups inherited?

Multiple alleles: A, B, O; A and B are codominant, O is recessive.

What are classes of genetic diseases and how are they inherited?

Autosomal dominant (e.g., Huntington’s), autosomal recessive (e.g., CF), X-linked (e.g., hemophilia), mitochondrial (maternal).

How are genetic disorders notated?

Dominant: Aa or AA. Recessive: aa. X-linked: XH Xh, Xh Y. Mitochondrial: inherited from mother.

How do you solve genetic problems?

Use Punnett squares to predict offspring genotypes and phenotypes.

How do you interpret a pedigree and determine genotypes?

Identify inheritance pattern; use symbols to deduce individual genotypes.

What is chromosomal nondisjunction and what disorders result?

Improper chromosome separation. Examples: Down syndrome (trisomy 21), Turner (XO), Klinefelter (XXY).

What is the structure of DNA and how does replication work?

DNA: double helix with A-T and C-G pairs. Replication is semi-conservative (one old strand, one new).

What happens during transcription and translation?

Transcription: DNA → mRNA (in nucleus). Translation: mRNA → protein (at ribosome, using tRNA and rRNA).

Why is gene regulation necessary and how is it controlled?

Ensures proper gene expression. Prokaryotes: operons. Eukaryotes: transcription factors, enhancers, repressors.

What are restriction enzymes, cloning, DNA fingerprinting, and PCR?

Restriction enzymes: cut DNA. Cloning: copying DNA or organisms. Fingerprinting: ID individuals. PCR: amplifies DNA.