Biology Exam 1 & 2 (Ch. 1, 2)

Exam 1 (Ch. 1, 2)

• Effects of pH on proteins: pH alters protein shape by affecting ionic and hydrogen bonds. Extreme pH levels denature proteins, losing their function.

• Characteristics of living things: Growth, reproduction, responsiveness to stimuli, metabolism, homeostasis, heredity, and cellular structure define living things.

• Central dogma: The central dogma describes the flow of genetic information from DNA to RNA to protein: DNA → RNA → Protein.

• Producers vs consumers: Producers (autotrophs) make their own food (e.g., photosynthesis), while consumers (heterotrophs) eat other organisms for energy.

• Water properties: Water has high surface tension, cohesion, adhesion, high specific heat, and is a good solvent due to hydrogen bonding.

• Organic compounds: Organic compounds contain carbon and are usually associated with living organisms (e.g., carbohydrates, proteins, lipids, nucleic acids).

Exam 2

• Ideal conditions for plant/animal cells (tonicity): Plant cells are ideal in hypotonic solutions. Animal cells perform best in isotonic solutions.

• Diffusion: The movement of molecules from high to low concentration.

• Factors affecting enzymes: Temperature, pH, enzyme concentration, substrate concentration, inhibitors, and activators influence enzyme activity.

• Enzyme structure and function: Enzymes speed up reactions by lowering activation energy. The substrate binds to the active site in an induced fit model.

• Animal vs. plant cells (structure): Plant cells have cell walls, chloroplasts, and large central vacuoles, unlike animal cells which have centrioles and lysosomes

• Endergonic vs. exergonic reactions: Endergonic reactions require energy input, while exergonic reactions release energy.

• Structures found in all cells: All cells have a plasma membrane, cytoplasm, ribosomes, and DNA.

• Conditions influencing plant/animal cells: Hypertonic solutions cause cells to shrink, hypotonic solutions cause them to swell. Isotonic solutions keep the cell's shape.

Exam 3

• Reduced vs oxidized in cellular respiration & photosynthesis: In cellular respiration, glucose is oxidized and oxygen is reduced. In photosynthesis, water is oxidized and carbon dioxide is reduced.

• Electron transport chain purpose: Transfers electrons through protein complexes, creating a proton gradient for ATP synthesis.

• Cellular respiration locations: Glycolysis occurs in the cytoplasm, the Krebs cycle in the mitochondria, and the electron transport chain in the inner mitochondrial membrane.

• Oxidation vs reduction: Oxidation is the loss of electrons and reduction is the gain of electrons.

• Autotrophic vs heterotrophic: Autotrophs make their own food (e.g., photosynthesis), while heterotrophs eat other organisms.

• Light reactions vs Calvin Cycle: Light reactions occur in the thylakoid membranes and the Calvin cycle occurs in the stroma.

• Products of light reactions: ATP, NADPH, and oxygen.

• Wavelengths best for photosynthesis: Red and blue wavelengths are most effective.

• ATP: Adenosine triphosphate is a primary energy source for cellular processes.

• Relationship between cellular respiration and photosynthesis: The products of photosynthesis are the reactants for cellular respiration, and vice versa.

• Cristae: Increase the surface area of mitochondria for ATP production.

• Chlorophyll absorption spectrum: Absorbs blue and red light efficiently, reflecting green light.

Exam 4

• DNA double helix structure: Two strands of nucleotides twisted around each other. The backbone is sugar and phosphate, paired nitrogenous bases (A with T, C with G) held together by hydrogen bonds.

• Chromosomes in human cells: Normal human diploid cells have 46 chromosomes (23 pairs). Haploid cells have 23 chromosomes.

• Percentage of nucleotides: Adenine (A) equals the percentage of thymine (T), and cytosine (C) equals the percentage of guanine (G).

• Purpose of mitosis: Cell division for growth, repair, and asexual reproduction. Results in genetically identical daughter cells.

• Base pairing rules: Adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G). These pairings are held by hydrogen bonds.

• Transcription & translation: Transcription copies a segment of DNA into mRNA. Translation decodes mRNA to synthesize proteins by ribosomes

• Point Mutation - Base Substitution: A single nucleotide change; base substitution is a specific type of point mutation.

• Nonsense mutation: A base substitution that changes a codon to a stop codon, ending protein synthesis prematurely.

• Mitotic spindle: A structure of microtubules that separates chromosomes during mitosis.

Additional Topics

• Cancer: Uncontrolled cell division due to mutations in genes that regulate the cell cycle.

• Leading and lagging strands: The leading strand is synthesised continuously, while the lagging strand is synthesised in short segments.

• Interphase: The phase of the cell cycle when the cell is not dividing (consists of G1, S, and G2).

• Gene: A segment of DNA that provides instructions for creating proteins or RNA.

• DNA vs RNA: DNA is double-stranded, contains deoxyribose sugar, uses thymine (T). RNA is single-stranded, contains ribose sugar, uses uracil (U) instead of thymine.

• Binary fission: Asexual reproduction in prokaryotes (bacteria) dividing into two identical daughter cells.

• Purpose of DNA replication: Ensures each daughter cell gets an exact copy of the genetic material during cell division.

• Mutation: A change in DNA sequence. Can be beneficial, neutral, or harmful.

• Codon chart: Used to translate mRNA codons into amino acids.

• Purpose of Meiosis: Produce haploid gametes (sperm and egg) for sexual reproduction.

• Natural selection: A process where organisms with favorable traits are more likely to survive and reproduce, passing those traits to the next generation.

• Homozygous vs Heterozygous: Homozygous individuals have identical alleles; heterozygous individuals have different alleles.

• Phenotype vs genotype: Genotype is the genetic makeup (alleles); phenotype is the physical expression (observable traits).

• Sex-linked traits: Traits found on the sex chromosomes (X or Y).

• Predicting probability of offspring outcomes: Using Punnett squares to determine the probability of offspring genotypes and phenotypes.

• Evolution: The change in the genetic makeup of populations over time, often influenced by natural selection.