Biology Spring Semester Final Exam Practice Questions

Evolution

Hardy-Weinberg Equilibrium Conditions

  • The 5 conditions for a population to be in Hardy-Weinberg Equilibrium:
    • No Mutations
    • No immigration/emigration
    • No natural selection
    • Random mating (no purposeful selection of partners)
    • A large population

Allele Frequencies and Equilibrium

  • Populations demonstrating Hardy-Weinberg equilibrium maintain stable allele frequencies.

Genetic Drift

  • Genetic drift is the change in frequency of an existing gene variant in the population due to random chance.
  • Example: Forest fire (the remaining organisms are not necessarily the original allele frequency)

Gene Flow

  • Gene flow is the passing of genes from a different population or species.
  • Example: Migration (one species migrates to a new ecosystem)

Speciation

  • Speciation is the evolutionary process by which a single ancestral species diverges into two or more distinct species.
  • Example: Galapagos Finches (species of birds that were spread across the Galapagos Islands and adapted to their environment)

Homologous Structures

  • Homologous structures are organs or bones of animals that show similar structure.

Vestigial Structures

  • Vestigial structures appear to have no purpose.
  • Example: A human Coccyx(tailbone)

DNA/Amino Acid Sequencing

  • Similarities between genes and proteins between organisms.

Evolutionary Relationships

  • Species with fewer amino acid differences are more closely related.

Fossil Layers

  • The oldest organisms are found in the deepest fossil layers.

Antibiotic Effectiveness

  • The effectiveness of antibiotics can be determined by observing their impact on bacterial growth in a petri dish.

Natural Selection

  • Overproduction: A species producing more offspring than can survive and reproduce.
  • Genetic Variation: The differences in the DNA sequences of genes among individuals and populations.
  • Competition: An interaction between organisms or species in which both require a resource that is in limited supply.
  • Survival of the Fittest: An interaction between organisms or species in which both require a resource that is in limited supply.
  • Descent with Modification: The concept that living organisms have evolved from common ancestors over time, with each subsequent generation inheriting traits from their predecessors, while also exhibiting modifications or changes in those traits.

Cladograms

  • Cladograms illustrate the evolutionary relationships between organisms.

Insecticide Resistance

  • Genetic variations can create resistance to crop pesticides, and those insects reproduce and pass down their resistance.

Natural Selection Curves

  • Stabilizing Selection: The intermediate phenotype shows the best fitness.
  • Disruptive Selection: The intermediate phenotype is the least fit.
  • Directional Selection: One extreme phenotype becomes better suited for the environment & the phenotypes shift in one direction.

Gradualism

  • Species change slowly and continuously over vast periods of time.

Punctuated Equilibrium

  • Species remain relatively stable for long stretches, with rapid periods of change occurring periodically, often during speciation events.

Defense Against Disease

Lytic Viral Infection

  • Step 1: Attachment: The virus attaches to the host cell through specific receptors on the cell surface.
  • Step 2: Entry: The virus injects its genetic material (DNA or RNA) into the host cell.
  • Step 3: RNA Synthesis: The viral genetic material is replicated using the host cell's machinery. The host cell's DNA is degraded, and the cell is directed to produce viral proteins.
  • Step 4: Assembly: New viral particles are assembled from the replicated DNA and proteins.
  • Step 5: Release: The host cell is lysed (burst open), and the newly assembled viruses are released to infect other cells.

Viral Replication

  • Viruses must use a living cell to replicate.
  • They lack the necessary internal machinery to perform essential life processes like protein synthesis and nucleic acid replication independently.

First Line of Defense

  • The first line of defense (the skin) protects against pathogens.
  • Physical: skin's outer layer
  • Chemical: Stomach acid
  • Biological: Tears, mucus, and saliva

Second Line of Defense

  • In the second line of defense (the inflammatory response), release of inflammatory mediators like cytokines and histamines, dilation of blood vessels to increase blood flow and leakage of blood components into the damaged tissue, and recruitment of white blood cells like neutrophils to the site of injury or infection.

Third Line of Defense

  • Helper T Cell: By activating and coordinating other immune cells to fight off infections. They do this by releasing cytokines, which are signaling molecules that tell other immune cells what to do.
  • Plasma B Cell: By producing and secreting large quantities of antibodies in response to specific antigens.
  • Memory B Cell: By providing a rapid and robust response upon re-exposure to a previously encountered pathogen.

Secondary Immune Response

  • The secondary immune response creates more antibodies and is quicker than the primary immune response.
  • Memory B Cells are responsible for this.

Animal Systems

Feedback Loops

  • Positive Feedback Loop: Amplifies a change, moving a system further away from its original state, rather than returning it to a stable equilibrium.
  • Negative Feedback Loop: A regulatory mechanism where a stimulus triggers a response that opposes the initial stimulus, bringing a system back to a stable state, or homeostasis.

Homeostasis

  • Homeostasis is the process by which living organisms maintain a stable internal environment despite external changes.

Body Systems

  • The body systems involved with antibodies and white blood cells are the immune and circulatory systems.

Dehydration Response

  • When dehydrated, the body uses a negative feedback loop.
  • Kidneys will respond by stopping urine production, sending the water from urine into your bloodstream to thin your blood back to normal level.

Plant Systems

Guard Cells and Stomata

  • Guard cells regulate stomata opening and closing by controlling their own water and solute content, effectively changing their shape and the size of the surrounding stomatal pore.
  • This control is crucial for plants as it balances gas exchange for photosynthesis with water conservation during transpiration.

Plant Tropisms

  • Phototropism: The directional growth or movement of a plant or part of a plant in response to light.
  • Thigmotropism: A plant's directional growth response to physical contact or touch with an object.
  • Gravitropism: A plant's directional growth or change in the direction of its growth in response to gravity.

Phototropism Hormone

  • Auxin is responsible for phototropism.
  • The shoot apical meristem produces the Auxin hormone.
  • Auxin builds up on the shaded side of the stem, which causes the shoot to bend toward the light.

Flower Anatomy

  • Key flower parts include:
    • Stigma
    • Pistil
    • Filament
    • Ovule
    • Sepal
    • Stamen
    • Petal
    • Style
    • Anther
    • Ovary

Root Hairs

  • They increase the surface area for absorption of water and essential nutrients from the soil.

Leaf Cross Section

  • Cuticle: The waxy outer layer that protects the leaf from water loss and provides a barrier against pathogens.
  • Upper Epidermis: A protective layer of cells that regulates gas exchange through stomata (tiny pores) and allows for light transmission.
  • Palisade mesophyll cell: The primary photosynthetic tissue, composed of palisade and spongy cells.
  • Xylem/Phloem: X-transports water, P-transports nutrients
  • Guard cell: Regulates the opening and closing of stomata, tiny pores on the leaf surface.
  • Stomata: Pores on the underside of the leaf that facilitate gas exchange (carbon dioxide uptake and oxygen release) during photosynthesis.

Stomata and Environment

  • Sahara desert: Closed
  • Tropical rainforest: Open
  • Swamp: Open

Ecology

Photosynthesis - Respiration Cycle

  • Key components include:
    • Mitochondria
    • Chloroplast
    • Oxygen
    • Carbon Dioxide
    • Glucose
    • Water
    • ATP

Cellular Respiration Equation

  • C6H{12}O6 + 6O2 \rightarrow 6CO2 + 6H2O + ATP

Photosynthesis Equation

  • 6CO2 + 6H2O + Light\,Energy \rightarrow C6H{12}O6 + 6O2

Trophic Levels

  • Labels for the pyramid:

    • Primary Consumer
    • Producer
    • Tertiary Consumer
    • Secondary Consumer
    • 1st Trophic Level
    • 4th Trophic Level
    • 3rd Trophic Level
    • 2nd Trophic Level
    • Carnivore
    • Carnivore
    • Producer
    • Herbivore
    • Most Energy
    • Most Biomass
    • Largest population

Predator-Prey Relationship

  • A big fish eating smaller fish is a predator-prey relationship.

Population Dynamics

  • If a predator population increases, the prey population will decrease.

Symbiotic Relationships

  • A water mold growing on a water plant, harming the plant, is a parasitic relationship.

  • Carnivore: Organism that eat meat

  • Omnivore: Organism that eats meat and plants

  • Herbivore: Organism that only eats plants

  • Detrivore: Organism that breaks down dead organic material for nutrients

Food Webs

  • Removing a species from a food web affects the populations that rely on it for food or are its prey.
  • The snake population would decrease if the hawk population increased.

Carbon Cycle

  • Photosynthesis removes carbon from the atmosphere.

Carbon Return

  • Carbon is returned to the atmosphere through:
    • Decomposition of organic matter
    • Cellular respiration
    • Combustion of fossil fuels
    • Volcanic eruptions

Nitrogen Cycle Components

  • Key terms for labeling the Nitrogen Cycle:

    • Nitrates
    • Denitrifying bacteria
    • Nitrogen-fixing bacteria
    • Plant
    • Animal
    • Decomposing organism

Ecological Succession

  • Primary succession: the initial colonization of a previously uninhabited environment, like newly exposed rock after a volcanic eruption or glacial retreat, by organisms
  • Pioneer species: the first organisms to colonize a previously barren or disturbed environment, initiating ecological succession
  • Secondary succession: the process of ecological recovery that occurs in an area where a pre-existing community has been disturbed, but not completely destroyed
  • Climax community: the stable, final stage of ecological succession in a specific environment

Symbiotic Relationships

  • Mutualism: is a relationship where both organisms benefit. Example: Water buffalo and Oxpeckers (Oxpecker eats the ticks off the water buffalo and the water buffalo are free from disease)
  • Parasitism: one organism is harmed and the other benefits. Example: tick and dog (tick feeds off the blood of a dog, the dog is harmed)
  • Commensalism: one organism benefits and the other is unaffected Example: Barnacle and Whale (the barnacles benefit by eating the microbes and the whale is not harmed or helped)