Biology Spring Exam Review 2024-2025

Transcription, Translation, Protein Synthesis and Mutations

Protein Synthesis:
- Definition: The process of creating proteins.
- Two Major Parts:
  - Transcription.
  - Translation.
- Location: Ribosomes in the cytoplasm.
Transcription:
- Definition: The process of creating mRNA from a DNA template.
- Location: Nucleus.
Translation:
- Definition: The process of creating a protein from an mRNA template.
- Location: Ribosomes in the cytoplasm.
Roles of RNA:
- mRNA (messenger RNA): Carries the genetic code from DNA to ribosomes.
- tRNA (transfer RNA): Brings amino acids to the ribosome to build a protein.
Unique Base in RNA:
- Uracil (U) replaces Thymine (T) found in DNA.
Organelles in Protein Synthesis:
- Ribosomes
- Endoplasmic Reticulum (ER).
Mutation:
- Definition: A change in the nucleotide sequence of DNA.
  - Point Mutation: A single nucleotide change.
  - Substitution Mutation: Replacement of one nucleotide with another.
  - Insertion Mutation: Addition of one or more nucleotides.
  - Deletion Mutation: Removal of one or more nucleotides.

Cell Cycle and Cell Division

Cell Cycle:
- Definition: The series of events that take place in a cell leading to its division and duplication of its DNA (replication) to produce two new daughter cells.
  - G1 Stage (Gap 1): Cell grows and performs normal functions.
  - S Phase (Synthesis): DNA replication occurs.
  - G2 Phase (Gap 2): Cell prepares for division.
  - M Phase (Mitotic Phase): Cell divides its nucleus (mitosis) and cytoplasm (cytokinesis).
  - Cytokinesis: Division of the cytoplasm to form two separate daughter cells.
Mitosis:
- Definition: A type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth.
- Cells: Somatic cells (body cells).
Stages of Mitosis:
- Prophase
- Metaphase
- Anaphase
- Telophase
Chromosomes in Mitosis (Start):
- Diploid (2n).
Chromosomes in Daughter Cells (Mitosis):
- Diploid (2n).
Comparison of Daughter Cells to Parental Cells (Mitosis):
- Genetically identical.
Meiosis:
- Definition: A type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell, as in the production of gametes and plant spores.
- Cells: Germ cells (sex cells).
Stages of Meiosis:
- Meiosis I (Prophase I, Metaphase I, Anaphase I, Telophase I).
- Meiosis II (Prophase II, Metaphase II, Anaphase II, Telophase II).
Chromosomes in Meiosis (Start):
- Diploid (2n).
Chromosomes in Daughter Cells (Meiosis):
- Haploid (n).
Comparison of Daughter Cells to Parental Cells (Meiosis):
- Genetically different; half the number of chromosomes.

Genetics

Genetics:
- Definition: The study of heredity and the variation of inherited characteristics.
Randomness in Genetics:
- Explanation: Due to the random assortment of chromosomes during meiosis and random fertilization.
- Genes and Chromosomes: Genes are located on chromosomes, which are randomly assorted during meiosis, leading to genetic variation.
Human Chromosomes from Parents:
- 23 chromosomes from each parent; Total 46.
Allele:
- Definition: A variant form of a gene.
  - Dominant Allele: An allele that expresses its phenotype even when heterozygous.
  - Recessive Allele: An allele that only expresses its phenotype when homozygous.
Monohybrid Cross:
- Definition: A cross between two individuals differing in a single trait.
  - Genotype: The genetic makeup of an organism.
  - Phenotype: The observable characteristics of an organism.
  - Homozygous Dominant: Having two dominant alleles (e.g., AA).
  - Heterozygous: Having one dominant and one recessive allele (e.g., Aa).
  - Homozygous Recessive: Having two recessive alleles (e.g., aa).
Complete Dominance:
- Definition: A form of dominance in heterozygous condition wherein the allele that is regarded as dominant completely masks the effect of the allele that is recessive.
  - Genotypes Possible: 3 (AA, Aa, aa).
  - Phenotypes Possible: 2 (Dominant phenotype, Recessive phenotype).
Punnett Square for Aa x Aa:
- Genotypes: AA, Aa, aa.
- Phenotype Percentages: 75% dominant, 25% recessive. Genotype Percentages: 25% AA, 50% Aa, 25% aa.
Incomplete Dominance:
- Definition: A form of intermediate inheritance in which one allele for a specific trait is not completely expressed over its paired allele. This results in a third phenotype in which the expressed physical trait is a combination of the phenotypes of both alleles.
- Example: Red flower (RR) crossed with white flower (WW) yields pink flower (RW).
Codominance:
- Definition: A relationship between two versions of a gene. Individuals receive one version of a gene, called an allele, from each parent. If the alleles are different, the dominant allele will be expressed. In codominance, however, neither allele is recessive and the phenotypes of both alleles are expressed.
- Example: Human blood type AB (both A and B antigens are expressed).
Sex-Linked Traits:
- Definition: Traits that are determined by genes located on sex chromosomes (typically the X chromosome).
- Example: Hemophilia, color blindness.
Multiple Alleles:
- Definition: Three or more possible alleles determine the phenotype.
- Example: ABO blood type in humans (IA, IB, i).
Polygenic Inheritance:
- Definition: A trait that is produced by the interaction of multiple genes.
- Example: Human height, skin color.
Dihybrid Cross:
- Definition: A cross between two individuals differing in two traits.
- Similarity to Monohybrid Cross: Both involve predicting offspring genotypes and phenotypes.
- Difference from Monohybrid Cross: Dihybrid crosses involve two genes, monohybrid only one.
- Phenotypes Possible: 4.
Dihybrid Cross Example (DdHh x DdHh):
- Phenotype percentages: 9/16 double dominant, 3/16 dominant for first trait and recessive for second, 3/16 recessive for first trait and dominant for second, 1/16 double recessive.

Pedigree Analysis

Pedigree:
- A diagram that shows the occurrence and appearance of phenotypes of a particular gene or organism and its ancestors from one generation to the next
Number of Generations:
- Determined by counting the rows in the pedigree chart.
Trait (Dominant or Recessive):
- Determined by analyzing the inheritance pattern in the pedigree.
Genotype of Individual II-2:
- Determined by analyzing the pedigree and the inheritance pattern of the trait.
Probability of Offspring Showing Trait (IV-4 and IV-5 Heterozygous):
- Based on Mendelian genetics and Punnett Square analysis.
Recessive Trait Expression:
- Must have two recessive alleles.

Chromosome Analysis

Karyotype:
- Definition: A display of the chromosome pairs of a cell arranged by size and shape.
Sex Determination:
- XX = Female
- XY = Male
Normal Chromosome Set:
- Humans should have 46 chromosomes (23 pairs).

Ecology and Energy

Ecology:
- Definition: The scientific study of the interactions between organisms and their environment.
Two Important Themes in Ecology:
- Energy flow.
- Nutrient cycling.
Levels of Ecological Organization:
- Population: A group of individuals of the same species living in the same area; Example: A group of deer in a forest.
- Community: All the different populations of species living in the same area; Example: All the plants, animals, and microorganisms in a forest.
- Ecosystem: All the living and nonliving components in an area; Example: A forest including the trees, animals, soil, water, and air.
- Important aspect: the interaction between biotic and abiotic factors affect the ecosystem.
- Biome: A large geographic area characterized by specific climate conditions, animal populations, and plant populations; Example: Desert, rainforest, tundra.
- Biosphere: The sum of all ecosystems on Earth; Example: The entire Earth with all its living organisms and environments.
Desert Food Chain (Cactus, Hawk, Insect, Snake):
- Cactus -> Insect -> Snake -> Hawk
Energy Transfer in Trophic Levels:
- 10% rule: Approximately 10% of the energy absorbed by one trophic level is transferred to the next successive level.
- Food Chain 1: phytoplankton -> smelt -> trout -> humans
- Food Chain 2: phytoplankton -> smelt -> humans
- Energy available to humans in Food Chain 2 is higher than in Food Chain 1 because there are fewer trophic levels, and therefore less energy is lost as heat.
Aquatic Food Web:
- Omnivore: An organism that eats both plants and animals.
- Herbivore: An organism that eats only plants.
- Carnivore: An organism that eats only animals.
- Leopard Seal Food Chain: phytoplankton -> krill -> fish -> leopard seal
Ecological Relationships:
- Mutualism: A relationship where both species benefit; Example: Bees pollinating flowers.
- Parasitism: A relationship where one species benefits and the other is harmed; Example: Ticks on a dog.
- Predation: A relationship where one species (predator) kills and eats another species (prey); Example: Lion hunting a zebra.
- Commensalism: A relationship where one species benefits and the other is neither harmed nor benefited; Example: Birds nesting in a tree.
Daphnia Population Growth:
- Type of Growth: Logistic growth.
- Logistic Growth: Population growth that levels off as population size approaches carrying capacity.
- Exponential Growth: Population growth that occurs at a constant rate; J-shaped curve.
- Carrying Capacity: The maximum population size that an environment can sustain given the food, habitat, water, and other necessities available.
- Largest Incline: The period during which the population increases most rapidly.
Non-Viable Offspring:
- Conclusion: The organisms are different species.
Cellular Respiration:
- Definition: The set of the metabolic reactions and processes that take place in the cells of organisms to convert chemical energy from oxygen molecules or nutrients into adenosine triphosphate, and then release waste products.
- Overall Equation: $C6H{12}O6 + 6O2 _rightarrow 6CO2 + 6H2O + ewline Energy(ATP)$
- Reactants: Glucose ( $C6H{12}O6$ ) and Oxygen ( $O2$ ).
- Products: Carbon Dioxide ( $CO2$ ), Water ( $H2O$ ), and Energy (ATP).
- Organisms: Both autotrophs and heterotrophs.
Photosynthesis:
- Definition: The process by which plants, algae, and some bacteria use sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar (glucose).
- Overall Equation: $6CO2 + 6H2O + Sunlight _rightarrow C6H{12}O6 + 6O2$
- Reactants: Carbon Dioxide ( $CO2$ ), Water ( $H2O$ ), and Sunlight.
- Products: Glucose ( $C6H{12}O6$ ) and Oxygen ( $O2$ ).
- Organisms: Autotrophs.
- Green Pigment: Chlorophyll.
Autotroph:
- Definition: An organism that can produce its own food using light, water, carbon dioxide, or other chemicals.
Heterotroph:
- Definition: An organism that cannot produce its own food, instead taking nutrition from other sources of organic carbon, mainly plant or animal matter.
Main Goal of Photosynthesis:
- To create glucose (sugar).
Main Goal of Cellular Respiration:
- To create ATP (energy).
Gas Required for Photosynthesis:
- Carbon Dioxide ( $CO_2$ ).
Gas Required for Cellular Respiration:
- Oxygen ( $O_2$ ).

Evolution

Father of Evolution:
- Charles Darwin.
- Travels: Galapagos Islands.
- Organisms Studied: Finches, tortoises.
Natural Selection:
- Definition: The process whereby organisms better adapted to their environment tend to survive and produce more offspring.
  - Variation: Differences in traits among individuals in a population.
  - Adaptation: A trait that helps an organism survive and reproduce in its environment.
  - Survival of the Fittest: The ability of an organism to pass on its genetic material to its offspring.
Divergent Evolution:
- Definition: The accumulation of differences between groups which can lead to the formation of new species, usually a result of different populations adapting to different environments.
Convergent Evolution:
- Definition: The independent evolution of similar features in species of different lineages, creating analogous structures.
Coevolution:
- Definition: The process in which two or more species reciprocally affect each other's evolution through natural selection.
Species Determination (Damselfishes):
- Based on the definition of a species (ability to interbreed and produce viable offspring), determine how many different species Dr. Romero is raising and which fish they are.
Jelly Bean Predation:
- Green jellybean because they are easily camouflaged on green grass.
Cockroach Resistance to Pesticide:
- Explanation: Some cockroaches had a genetic mutation that made them resistant to the pesticide. These cockroaches survived, reproduced, and passed on the resistance gene to their offspring. Over time, the population became more resistant to the pesticide.

Classification and Taxonomy

Levels of Classification:
- Domain
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
Broadest and Least Broad Levels of Classification:
- Broadest (Least Specific): Domain.
- Least Broad (Most Specific): Species.
Dichotomous Key:
- Definition: A tool that allows the user to determine the identity of items in the natural world, based on the premise that every living thing can be progressively divided into two groups.
Phylogenetic/Evolutionary Tree (Cladogram):
- Definition: A branching diagram showing the evolutionary relationships among various biological species or other entities based upon similarities and differences in their physical or genetic characteristics.
Relationship of Dog to Kingsnake and Goldfish:
- Dog is more closely related to the kingsnake.
Most Ancestral Trait:
- The trait shared by the most organisms.
Trait Shared by Dog and Kingsnake Only:
- The specific trait that distinguishes them from the other organisms.
Stick Insect Relationship:
- How the stick insect is related to the rest of the organisms.