Biology Milestone (EOC)

Characteristics of Living Things

• Respond to the environment

• Metabolism

• Homeostasis

• Growth and Development

• Genetic Material (DNA or RNA)

• Made of cells

• Reproduction

Scientific Method

• Problem

• Hypothesis

• Design an experiment

• Data collection

• Data analysis

• Conclusion

Elements of an Experiment

• Independent variable (manipulating variable): The variable that is changed in an experiment by the researcher.

• Dependent variable (responding variable): The variable that responds to the independent variable. The variable that is measured.

• Experimental group: Group that is changed.

• Control group: All variables are held constant. Used as a comparison for the experimental group.

Reading a Graph

• Read the labels on both the horizontal axis and the vertical axis; look to see how they relate to the subject of the graph.

Properties of Water

• Polar molecule

• Forms hydrogen bonds with other molecules

• Adhesion: Water sticks to non-water molecules and allows water to move up plants.

• Cohesion (high surface tension): Water sticks to water.

• Heat capacity: Resists change to temperature.

• Expands when it freezes (less dense).

• Heat of vaporization: Cools substances as evaporates.

Hydrogen Bonds

• Bonds between hydrogen and other elements, usually weaker, give water its special properties.

Macromolecules: The 4 Major Polymers in Living Things

• Polymer: Carbohydrate

  • Monomer: glucose

  • Elements: C, H, O

  • Examples: glucose, cellulose, starch, fructose, glycogen

  • Function: Short term energy storage

• Polymer: Protein

  • Monomer: amino acids

  • Elements: C, H, O, N, S

  • Examples: enzymes, hormones

  • Function: Build muscle

• Polymer: Nucleic Acid

  • Monomer: nucleotide

  • Elements: C, H, O, N, P

  • Examples: DNA, RNA

  • Function: Storage of genetic information

• Polymer: Lipid

  • Monomer: triglycerides

  • Elements: C, H, O, P, S

  • Examples: Fats, oils, steroids, cholesterol

  • Function: Insulation, long term energy storage (most energy/gram)

Enzymes

• Proteins that lower activation energy for a reaction and speeds up the chemical reaction.

Microscopy

• Total magnification is calculated by multiplying the eyepiece magnification by the objective magnification.

• Example: Eyepiece 10X and Objective 4X gives a Total Magnification = 40x

• Light microscope: Used to view cells and other objects.

• Electron microscopes: Are used to study sub-cellular structure and viruses

Cells

• Prokaryotic Cells:

  • Smaller than eukaryotic cells.

  • Do not contain a true nucleus or membrane-bound organelles.

  • Can have pili or flagella to help with movement.

  • Example: Bacteria

• Eukaryotic Cells:

  • Contains a true nucleus and membrane-bound organelles.

  • Example: All kingdoms except the two bacterial kingdoms

Endosymbiosis Theory

• One prokaryotic cell engulfed another prokaryotic cell, and they began to work together.

  • Evidence: both chloroplast and mitochondria have DNA, double membranes and make energy.

Structures of Cells

• Cell membrane/Plasma Membrane

  • Function: Allows some things in or out (selectively permeable)

  • Where: prokaryotic and eukaryotic cells (animal and plant)

• Nucleus

  • Function: Controls cell activity and contains DNA

  • Where: eukaryotic cells (animal and plant)

• Mitochondria

  • Function: Produces energy (ATP) for the cell

  • Where: eukaryotic cells ( animal and plant)

• Lysosomes

  • Function: Break down waste material in the cell using enzymes

  • Where: eukaryotic cells (animal only)

• Golgi apparatus (body)

  • Function: Packages/modifies proteins for export

  • Where: eukaryotic cells (animal and plant)

• Smooth endoplasmic reticulum (no ribosomes on surface)

  • Function: lipids are made

  • Where: eukaryotic cells (animal and plant)

• Rough endoplasmic reticulum (ribosomes on surface)

  • Function: Modifies and transports proteins within cell

  • Where: eukaryotic cells (animal and plant)

• Ribosomes

  • Function: Makes proteins

  • Where: eukaryotic cells and prokaryotic cells

• Vacuole

  • Function: Storage of materials

  • Where: eukaryotic cells (animal and plant)

• Cell wall

  • Function: Provides support and protection

  • Where: eukaryotic cells (plant only)

• Chloroplast

  • Function: Site of photosynthesis

  • Where: eukaryotic cells (plant only)

• Vesicle

  • Function: Membrane bound sacs Pinch off of Golgi and ER

Structure of Cell Membrane

• Selectively permeable phosphorous bi-lipid membrane with protein channels (allows some things in and out)

Diffusion

• Movement of substances from an area of high concentration to an area of low concentration.

• Types of diffusion:

  • Facilitated diffusion: Requires the help of transport proteins.

  • Osmosis: The diffusion of water, which moves to dilute.

Types of Osmotic Solutions

• Salt Sucks: Salt is a solute, when it is concentrated inside or outside the cell, it will draw the water in its direction. Water always moves to dilute.

• More solute: hypertonic

  • Water moves out of the cell, cell shrinks

• Less solute: hypotonic

  • Water moves into cell, cell swells

• Same amount of solute: isotonic

  • Water moves into and out of cell at equal rates, cell stays the same.

Active Transport

• Requires energy (ATP) to move substances from an area of low concentration to high concentration.

• Example: Sodium (Na) potassium (K) ion pumps in humans.

• Types of active transport:

  • Endocytosis: Material is taken into the cell.

  • Exocytosis: Material is removed from the cell.

Cell Cycle

• Interphase: G1 - cell grows, S- DNA replicates, G2- more growth and prepping for mitosis.

Cell Reproduction

Cellular Energy

ATP

• Stores energy; Adenosine Triphosphate.

DNA /RNA

Protein Synthesis (R-T-T)

• Replication: DNA replicates and copies itself (Nucleus)

• Transcription: mRNA (messenger RNA) copies the code from DNA (Nucleus)

• Translation: Converts mRNA code into a polypeptide (protein) with tRNA at the ribosomes

Gene

• Segment of DNA that produces proteins

Punnett Squares

• A diagram used to show the probable outcome of a genetic cross.

Genotype

• Genetic makeup; Ex, BB

Phenotype

• Physical makeup; Ex, Brown hair

Mendel’s 3 Laws

• Law of Segregation: Only one allele from each parent is passed to offspring.

• Law of Independent Assortment: Genes for different traits are inherited independent of each other.

• Law of Dominance: One allele is dominant over the other allele.

Patterns of Inheritance

• Co-dominance: Both traits are expressed.

  • Ex. Chick-fill-a cows and AB blood type.

• Incomplete dominance: Blending of traits.

  • Ex. Red flowers and white flowers produce pink flowers.

• Multiple alleles: Trait is controlled by more than 2 alleles.

  • Ex. Blood types A,B,O

• Polygenic traits: Trait is controlled by more than one gene, which results in different combinations.

  • Ex. Skin color and eye color

• Sex linked traits: Trait is located on the X or Y chromosome.

  • Ex. Color blindness

Karyotype

• Profile of a person’s chromosomes

Reading a Karyotype

• There should be 22 pairs of somatic chromosomes and one pair of sex chromosomes (#23) for a total of 46 chromosomes. If the number varies than there is a genetic disorder. Nondisjunction during meiosis leads to this chromosomal aberration. Down syndrome = 3 chromosomes at number 21 (trisomy 21)

Gene Therapy

• An absent or faulty gene is replaced by a normal working gene using transgenic technology

Mutations

• Change in the DNA sequence

Types of Mutations

• Deletion: nucleotide is deleted or lost (frameshift mutation)

• Insertion: extra nucleotide is added to DNA (frameshift mutation)

• Substitution: one nucleotide substituted for another (point mutation)

• Nondisjunction: chromosomes do not separate during meiosis= 1 extra or 1 missing

• Inversions, duplications and translocations are when sections of chromosomes are changed.

Pedigree

• A chart that shows a family’s inheritance for a given trait. Squares represent males and circles represent females. If the square/circle is shaded in the person has the trait. If the square/circle is half shaded in then they are a carrier for the trait.

Genetic Engineering

• Selective Breeding: Choosing organisms with the desired traits and breeding them together to produce offspring with the desired traits. GMOs!

• Cloning: producing a genetically identical copy

Gel Electrophoresis

• Used to separate DNA fragments according to their size = DNA fingerprint

DNA Fingerprinting

• Used to separate DNA fragments according to their size = DNA fingerprint

Recombinant DNA

• Genes from one organism are placed into another organism.

Transgenic Organisms

• An organism that contains genes that has been transferred from another organism.

Evolution

• Darwin: developed the theory of Natural Selection= VSR explains how evolution occurs

• Lamarck: thought evolution was inheritance of acquired characters. Kangaroos grow and acquire large leg muscles and then pass those large muscles on to their offspring.

Natural Selection

• The mechanism in which favorable heritable traits are passed from one generation to another (VSR). This allows organisms with the favorable trait to survive and reproduce.

Antibiotic Resistance

• Natural selection of bacteria. Bacteria that survive antibiotic treatments and pass resistance to next generation.

Evidence of Evolution

• Fossil record: Shows how species have changed over time.

• Homologous structures: Same structure, different function

• Analogous structures: Different structure, same function

• Embryonic development: Vertebrate embryos look very similar

• Vestigial structures: Structures that are useless for the function originally performed.

• Biochemical & genetic analysis: Similarities between proteins and DNA and genes.

Speciation

• Formation of a new species

  • Reproductive isolation: When members of two populations cannot interbreed to produce fertile offspring.

  • Geographic isolation: Two populations become isolated by geographical barriers.

    • Convergent evolution: Distantly related organisms have evolved to resemble each other over time.

    • Divergent evolution (AKA – adaptive radiation): Ancestral species evolve into lots of different species.

    • Coevolution: One organism evolves in response to change in another organism. We see this with most symbiotic relationships. Co-evolution = mutualism

    • Gradualism: Idea that evolution occurs slowly and gradually over time

    • Punctuated Equilibrium: Long stable periods of equilibrium interrupted by brief periods of rapid evolution.

    • Rate of Evolution: The higher the biodiversity and variation, the faster the rate of evolution

Types of Selection

• Stabilizing: Individuals in the center curve have the advantage

• Directional: Individuals at one end of the curve have the advantage

• Disruptive: Individuals at both ends of curve are favorable

Cladogram

• A diagram depicting patterns of shared derived characteristics of various organisms

  • Remember that when you read the cladogram, that the characteristics are related to the organisms to the right of the characteristics. Ex. Organisms with fingers and toes are amphibians and land vertebrates

Levels of Classification

• Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Domains

• Achaea: Ancient prokaryotes (archaebacteria)

• Eubacteria: More advanced prokaryotes; “true” bacteria

• Eukarya: Eukaryotes

Kingdoms

• Archaebacteria: prokaryotes domain – archae

• Eubacteria: prokaryotes domain – eubacteria

• Protista: eukaryotes

• Fungi: eukaryotes; ALL Heterotrophic

• Plants: eukaryotes; ALL Autotrophic

• Animals: eukaryotes

Viruses

• Non-living but contain genetic material and protein layer. Cannot reproduce on their own and are NOT made of cells. Viruses are VERY SMALL = nanometers; (nm)

Ecological Levels of Organization

• Biosphere: Where life exists

• Biome: A group of ecosystems that have the same climate and similar organisms

• Ecosystem: All of the living things and nonliving parts of the environment.

• Community: All the different species living together in a particular area.

• Population: A group of individuals that belong to the same species in a particular area.

• Organism: An individual living things.

Food Web

• A series of different food chains

Food Chain

• Shows the flow of energy within an ecosystem. 10% of energy is passed onto each trophic, while 90% is lost as heat energy that is used for life processes.

Trophic Levels

• Producers (autotrophs): Make own food from the sun or chemicals.

• Herbivore (consumer): eats only producers

• Carnivore (consumer): eats only consumers

• Omnivore (consumer): eats both producers and consumers

• Detrivores: Feed off the remains of dead animals and plants Ex. Earthworm

• Decomposers: Break down organic matter and release energy from it Ex. Bacteria and fungi

Ecological Pyramids

• Energy pyramid: Rule of 10: Only 10% of energy transferred from one trophic level to another.

• Biomass pyramid: Total amount of living material in a trophic level.

• Pyramids of number: The number of organisms in a trophic level.

Succession

• The gradual and orderly process of change in an ecosystem

• Primary succession: No life has previously existed, and there is no soil ex. New island formed by volcanic eruption. Pioneer species is usually lichens or mosses.

• Secondary succession: Existing ecosystem is disturbed, and a new ecosystem develops in the same place ex. Forest fire. Pioneer species is usually grasses or weeds.

Biomes

Cycles of Nature

• Carbon cycle is basically cellular respiration cycling with photosynthesis. Also be sure to know process of Nitrogen fixation(conversion N gas to N solid), which is performed by nitrogen- fixing bacteria.

Greenhouse Effect

• A buildup of carbon dioxide and other gases that traps the sun’s rays, which can lead to global warming.

Global Warming

• An increase in the average temperature of the biosphere caused from burning fossil fuels and deforestation, which increases $CO_2$ and other greenhouse gasses. These gasses are “like a blanket” covering the Earth.

Types of Tropisms

• Gravitropism/Geotropism: Movement of a plant due to gravity (plant up and roots down)

• Thigmotropism: Movement of a plant due to touch (like climbing vines)

• Phototropism: Movement of a plant due to sunlight

• Hydrotropism: Movement of plant due to water

Types of Behaviors

• Kinesis: Movement in response to a stimulus

• Innate: Behavior born with aka instinct

• Classical conditioning (learned behaviors)

• Mimicry, estivation, camouflage, hibernation, migration, etc.

Symbiosis

• Any relationship in which two species live closely together

  • Mutualism: Both species benefit (often product of co-evolution)

  • Commensalism: One species benefits and the other species is unaffected

  • Parasitism: One species benefits and the other species is harmed

Population Density

• The number of individuals in a defined area.

Exponential Growth

• Population growth continues to get faster and faster until it is out of control. J- shaped.

Logistic Growth

• When population shows down after it reaches the carrying capacity. S-shaped

• Carrying capacity: Maximum population size an ecosystem can support. If population EXCEEDS carrying capacity, it may crash.

• Respond to the Environment: Living organisms respond to various stimuli such as light, temperature, and sound. This ability allows them to react and adapt to changes in their surroundings, which is vital for survival.

• Metabolism: All living things undergo metabolic processes that include anabolism (building up) and catabolism (breaking down). These reactions convert food into energy, which is essential for various cellular activities.

• Homeostasis: The process by which a living organism maintains a stable internal environment despite external changes. Maintaining homeostasis is critical for optimal functioning and survival.

• Growth and Development: Living organisms undergo systematic changes and growth throughout their life cycles, driven by genetic information. This encompasses both physical growth and developmental stages, leading to maturity.

• Genetic Material (DNA or RNA): Living things carry genetic information in the form of DNA (deoxyribonucleic acid) or RNA (ribonucleic acid). This information is essential for reproduction, inheritance, and functioning of the organism.

• Made of Cells: All living organisms are composed of cells, which are the basic units of life. Cells can be prokaryotic (lacking a nucleus) or eukaryotic (with a nucleus) and perform various functions necessary for life.

• Reproduction: Living organisms have the ability to reproduce, either asexually (one parent) or sexually (two parents), ensuring the continuation of their species. Reproduction involves the transfer of genetic material to offspring, contributing to biodiversity

Endosymbiosis Theory posits that eukaryotic cells originated through a symbiotic relationship between different species of prokaryotes. According to this theory, a prokaryotic cell engulfed another prokaryotic cell, and instead of being digested, the engulfed cell formed a beneficial relationship with the host cell. Over time, the engulfed cell evolved into specialized organelles like chloroplasts and mitochondria, which are essential for eukaryotic cell function.

Evidence Supporting Endosymbiosis Theory

• DNA Similarity: Both mitochondria and chloroplasts contain their own DNA, which is circular and resembles bacterial DNA more than eukaryotic nuclear DNA.

• Double Membranes: Both organelles have double membranes, consistent with the idea of a prokaryotic cell being engulfed by another cell.

• Reproduction: Mitochondria and chloroplasts replicate independently of the cell cycle through a process similar to binary fission, which is characteristic of bacteria.

• Ribosomal Similarities: The ribosomes in mitochondria and chloroplasts resemble those of prokaryotes, being smaller than those found in eukaryotic cells and similar to bacterial ribosomes.

• Phylogenetic Relationships: Genetic analyses show that the genomes of mitochondria and chloroplasts are more closely related to certain groups of bacteria than to the nuclear genomes of eukaryotes.

Implications

The endosymbiosis theory has profound implications for understanding the evolution of complex life forms on Earth. It suggests that the cooperation and merging of different organisms can lead to greater biological complexity and diversity, laying the groundwork for the vast array of eukaryotic life observed today.