BIOLOGY EOC Reveiw

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• Understanding the basis of life: Develop an understanding of the physical, chemical, and cellular basis of life.

Organic Molecules

• Definition: Organic compounds contain carbon and are found in all living things.

• Carbohydrates:

  • Major source of energy, including sugars and starches.

  • Composed of carbon, hydrogen, and oxygen.

  • Hydrogen to oxygen ratio is 2:1 ($H:O = 2:1$).

  • Plants and animals use them for maintaining structure within cells.

• Proteins:

  • Nitrogen-containing compounds made up of chains of amino acids.

  • 20 amino acids can combine to form a great variety of protein molecules.

  • Can compose enzymes, hormones, antibodies, and structural components.

• Lipids:

  • Water-insoluble (fats and oils) made up of carbon, hydrogen, and oxygen; composed of glycerol and fatty acid.

  • Provide insulation, store energy, cushion internal organs, found in biological membranes.

  • Saturated: With hydrogen, single bonds.

  • Unsaturated: Double bonds.

• Nucleic Acids:

  • Direct the instruction of proteins, genetic information an organism receives from its parents.

  • Two types: DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).

Cell Organelles

• Chloroplast: Capture solar energy for photosynthesis (plant cells, some algae).

• Golgi Body: Package and distribute products.

• Lysosomes: Digest excess products and food particles.

• Mitochondria: Transform energy through respiration.

• Nucleus: Contains DNA, which controls cellular activities.

• Ribosome: Produce proteins.

• Vacuole: Store substances.

• Cell (plasma) membrane: Phospholipid bilayer that protects and encloses the cell; controls transport; maintains homeostasis.

• Cell wall: Rigid second layer that protects and encloses the cell (plant cells and some bacteria).

• Cytoplasm: Fluid-like substance that contains various membrane-bound structures (organelles) that perform various functions.

• Endoplasmic Reticulum: Site of chemical reactions.

  • Rough: Contains ribosomes.

  • Smooth: Lipid production.

• Cytoskeleton: Provides internal structure.

  • Microfilaments: Fibers.

  • Microtubules: Cylinders.

Cell Types

• Unicellular: Organism that exists as a singular, independent cell.

• Multicellular: Organism that exists as specialized groups of cells; cells are organized into tissues that perform the same function; tissues form organs and organs make up an organ system.

• Prokaryote: Has nuclear material in the center of the cell, but is not enclosed by a nuclear membrane; no membrane-bound organelles; found in bacteria and blue-green bacteria.

• Eukaryote: Contain a clearly defined nucleus enclosed by a nuclear membrane and membrane-bound organelles; found in plants, animals, fungi, and protists.

Cell Theory

• The cell is the basic unit of life.

• All organisms are composed of cells.

• All cells come from pre-existing cells.

Cell Specialization

• Cells >>>> tissues >>>> organs >>>> organ systems >>>> organism

• Each cell performs a specific function for each tissue or organ.

• As cells mature, their shape and contents change.

• As cells become specialized, they may contain organelles that are NOT common to all cells (for example: plastids, cell wall, vacuole, centriole).

• Design and shape of a cell are dictated by its function and the conditions under which it works.

• Multicellular organisms exhibit greater cellular specialization, such as red blood cells, nerve cells, and gland cells.

CELL TRANSPORT

• Passive Transport: Movement of substances across the plasma membrane without the use of the cell’s energy (with the concentration gradient).

  1. Diffusion: Movement of substances across the plasma membrane from an area of high concentration to an area of low concentration.

  2. Osmosis: Diffusion of water across the plasma membrane from areas of high concentration to areas of lower concentration.

  3. Facilitated Transport: A carrier molecule embedded in the plasma membrane transports a substance across the plasma membrane following the high-to-low concentration gradient.

• Active Transport: Movement of substances across the plasma membrane that requires the use of the cell’s energy and carrier molecules; substances are moving from an area of low concentration to an area of higher concentration (against the concentration gradient).

  1. Endocytosis: Large particles are brought into the cell.

  2. Exocytosis: Large particles leave the cell.

• Homeostasis: Internal equilibrium; the plasma membrane regulates what enters and leaves the cell; a selectively permeable membrane only allows certain substances to pass through.

• Effect of Concentration on a Cell

  1. Hypotonic: Water moves in; cell bursts.

  2. Hypertonic: Water moves out; cell shrivels.

  3. Isotonic: No net movement; cell maintains equilibrium.

HOMEOSTASIS

• Self-regulating mechanism that maintains internal conditions (with individual cells and within organs, systems).
  *Example: body temperature, respiration, nutritional balance, etc.

• Cells communicate their needs to each other mainly through their cell membranes by releasing chemical messengers that, ultimately, tell the hypothalamus gland in the brain that a change needs to be made in the interstitial fluid. Since it is the ruler of homeostasis, the hypothalamus sends neural and chemical signals to other glands, tissues, organs, and organ systems to adjust the internal environment, the interstitial fluid, so that it is more suitable for all the cells at that particular time. And since we are always changing what we are doing, homeostasis needs to change along with our activities, both day and night. This constantly changing internal environment is the process of homeostasis.

• Negative Feedback: Glucose / Insulin levels in cells

• Positive Feedback: Blood platelets / Blood clotting

BIOCHEMICAL REACTIONS

*Chemical bonds are formed and broken within living things creating chemical reactions that impact the ability to maintain life and carry out life functions.

• Cellular Respiration:

  • Food molecules are converted to energy; there are three stages to cellular respiration; the first stage is called glycolysis and is anaerobic (no oxygen is required); the next two stages are called the citric acid cycle and the electron transport chain and are aerobic (oxygen is required).

  • $C<em>6H</em>{12}O<em>6 + 6O</em>2 \Rightarrow 6CO<em>2 + 6H</em>2O + ENERGY (36 ATP)$

• Photosynthesis:

  • Plant cells capture energy from the Sun and convert it into food (carbohydrates); plant cells then convert the carbohydrates into energy during cellular respiration; the ultimate source of energy for all living things is the Sun (in Chemosynthesis, organisms use sulfur or nitrogen as the main energy source).

  • $6CO<em>2 + 6H</em>2O + ENERGY(from sunlight) \Rightarrow C<em>6H</em>{12}O<em>6 + 6O</em>2$

• ATP:

  • ATP is a molecule that stores and releases the energy in its bonds when the cell needs it; removing a phosphate group (P) releases energy for chemical reactions to occur in the cell and ATP becomes ADP; when the cell has energy, the energy is stored in the bond when the phosphate group is added to the ADP.

  • $ATP \Leftrightarrow ADP + P + ENERGY$

• Fermentation:

  • When cells are not provided with oxygen in a timely manner, this process occurs to continue producing ATP until oxygen is available again; glucose is broken down; there are two types of fermentation.

  • Lactic Acid Fermentation (muscle cells):

    • $Glucose \Rightarrow Lactic Acid + 2ATP$

  • Alcoholic Fermentation (plant cells):

    • $Glucose \Rightarrow CO_2 + Alcohol + 2ATP$

ENZYMES

• Enzymes are special proteins that regulate nearly every biochemical reaction in the cell. Different reactions require different enzymes.

• Enzymes function to:

  • Provide energy to cells

  • Build new cells

  • Aid in digestion

  • Break down complex molecules (“substrate” = reactant)

  • Catalysts (speed up chemical reactions without being used up or altered)

• Factors that affect enzymes: pH, temperature, and quantity

COMPARISON OF CELLULAR RESPIRATION, PHOTOSYNTHESIS AND CHEMOSYNTHESIS

AEROBIC AND ANAEROBIC RESPIRATION

• Aerobic Respiration:

  • Requires the presence of oxygen.

  • Release of energy from the breakdown of glucose (or another organic compound) in the presence of oxygen.

  • Energy released is used to make ATP, which provides energy for bodily processes.

  • Takes place in almost all living things.

• Anaerobic Respiration:

  • Occurs in the absence of oxygen.

  • Breakdown of food substances in the absence of oxygen with the production of a small amount of energy.

  • Produces less energy than aerobic respiration.

  • Often called fermentation.

  • Seen as an adaptation for organisms that live in environments that lack oxygen.

MOLECULAR BASIS OF HEREDITY

• DNA Replication, Protein Synthesis (Transcription, Translation), Gene Regulation

CHARACTERISTICS OF SEXUAL AND ASEXUAL REPRODUCTION

PATTERNS OF INHERITANCE

• Dominant / Recessive / Intermediate Traits, Multiple Alleles, Polygenic Inheritance, Sex-Linked Traits, Independent Assortment, Test Cross, Pedigrees, Punnett Squares

IMPACT OF ADVANCES IN GENOMICS ON INDIVIDUALS AND SOCIETY

• Human Genome Project, Applications of Biotechnology

DEVELOPMENT OF THEORY OF EVOLUTION BY NATURAL SELECTION

• Origin and History of Life, Fossil and Biochemical Evidence, Mechanisms of Evolution, Applications (Pesticides and Antibiotic Resistance)

COMPARISON OF DNA AND RNA

DNA & RNA

• Nucleic acids composed of nucleotides

• Nucleotides composed of:

  • Phosphate group

  • Sugar

  • Nitrogenous base

Asexual Reproduction

• a single parent produces one or more identical offspring by dividing into two cells

  • mitosis (protists, arthropods,
    bacteria by binary fission, fungi, plants); produces large numbers of offspring

  • offspring are clones of parents (genetically identical)

  • common in unicellular organisms, good for stable environments

  • budding, binary fission, conjugation

  • quick process (low energy requirement) – produces high number of offspring

Sexual Reproduction

• pattern of reproduction that involves the production and fusion of haploid sex cells; haploid sperm from father fertilizes haploid egg from mother to make a diploid zygote that develops into a multicellular organism through mitosis

  • results in genetic variation (diversity)

  • common in multicellular organisms (external or internal fertilization); good for changing environments

  • slow process (high energy requirement) – produces low number of offspring

  • meiosis = formation of sex cells (gametes)

CELL DIVISION

• process of copying and dividing the entire cell

• the cell grows, prepares for division, and then divides to form new daughter cells

• allows unicellular organisms to duplicate in a process called asexual reproduction

• allows multicellular organisms to grow, develop from a single cell into a multicellular organism, make other cells to repair and replace worn out cells

• three types: binary fission (bacteria and fungi), mitosis, and meiosis

DNA Protein Synthesis

• Transcription and Translation

COMPARISON OF MITOSIS AND MEIOSIS

GENETICS

branch of biology that deals with heredity

• Gregor Mendel experimented with sweet pea plants in 1800s

• Trait – characteristic an individual receives from its parents

• Gene – carries instructions responsible for expression of traits; a pair of inherited genes controls a trait; one member of the pair comes from each parent; often called alleles

• Homozygous – two alleles of a pair are identical (BB or bb)

• Heterozygous – two alleles of a pair are different (Bb); often called “hybrid”

• Dominant – controlling allele; designated with a capital letter

• Recessive – hidden allele; designated with lower-case letters

• Genotype – genetic makeup of an organism (represented by the letters)

• Phenotype – physical appearance of an organism (description of the letters)

• Monohybrid – cross involving one trait

• Dihybrid – cross involving two traits

• Punnett Square – graphic organizer used to show the probable results of a genetic cross

• Pedigree – graphic organizer to map genetic traits between generations

• Karyotype – chart of metaphase chromosome pairs to study chromosome number / diseases

• Test Cross – mating of an individual of unknown genotype with an individual of known genotype; can help to determine the unknown genotype of the parent

MENDELS LAWS OF HEREDITY

1. Law of Dominance

   • the dominant allele will prevent the recessive allele from being expressed

   • recessive allele will appear when it is paired with another recessive allele in the offspring

2. Law of Segregation

   • gene pairs separate when gametes (sex cells) are formed

   • each gamete has only one allele of each gene pair

3. Law of Independent Assortment

   • different pairs of genes separate independently of each other when gametes are formed (Anaphase II in Meiosis)

PATTERNS OF INHERITANCE

• Sex Chromosomes - 23rd pair of chromosomes; Males = XY; Females = XX

• Sex-Linked Traits

  • traits associated with particular sexes

  • X-Linked Traits inherited on X chromosome from mother (ex: colorblindness, baldness, hemophilia)

• Linked Traits

  • genes are linked on chromosomes; genes on same chromosome are inherited together; ex: red hair and freckles

  • one trait controlled by many genes (ex: hair color, eye color, skin pigment)

• Multiple Alleles

  • presence of more than two alleles for a trait (ex: eye color)

• Polygenic Inheritance

  • one trait controlled by many genes (ex: hair color, skin color); genes may be on the same or different chromosomes

• Codominance

  • phenotypes of both homozygous parents are produced in heterozygous offspring so that both alleles are equally expressed (ex: black chicken + white chicken = checkered chickens), (ex: sickle cell anemia)

• Incomplete Dominance

  • phenotype of a heterozygote is intermediate between the two homozygous parents; neither allele is dominant, but combine to display a new trait (ex: red flower + white flower = pink flower)

• Dominance / Recessive ness

  • observed trait is controlled by a homozygous genotype

  • ex: dominance disease – Huntington’s; ex: recessive disease – Cystic Fibrosis and Tay Sach’s

SOURCES OF VARIATION

• Crossing Over

  • genes from one chromosome are exchanged with genes from another chromosome

  • occurs regularly during meiosis and leads to greater genetic variation

  • many different phenotypes are a result of the random assortment of genes that occurs during sexual reproduction

• Nondisjunction

  • during meiosis, homologous pairs of chromosomes don’t separate

  • results in half the sex cells having an extra chromosome and the other half having one less chromosome

  • if fertilization occurs with an abnormal sex cell, zygote formed will have either one extra (trisomy) or one less (monosomy) than the diploid number (ex: Down’s Syndrome caused by extra 21st chromosome)

• Genetic Variation

  • influenced by crossing over, mutations, genetic engineering, random assortment of genes, natural selection

  • genetic variation controlled by sexual reproduction (does not occur in asexual reproduction)

  • gene regulation vs. gene expression – the expression of genes is regulated by turning genes on / off or amount of action

  • environment can influence magnitude of gene expression (ex: improper nutrition can prevent proper bone growth)

MUTATIONS

• change in genetic code

• passed from one cell to new cells

• transmitted to offspring if occurs in sex cells

• most have no effect

  • Gene Mutation – change in a single gene

  • Chromosome Mutation – change in many genes

• Can be spontaneous or caused by environmental mutagens (radiation, chemicals, etc.)

GENETIC ENGINEERING (GENOMICS)

• sometimes called biotechnology

• process of transferring a gene (DNA) from one organism to another

• Organisms with transferred gene now produce “recombined” genetic code ( called “recombinant DNA”)

• Ex: insulin produced through bacteria

• Ex: oil-eating bacteria

• Has application in medicine, environment, industry, agriculture, selective breeding

• Human Genome Project - DNA Fingerprinting

KARYOTYPE

• LAWS OF PROBABILITY TO PREDICT INHERITANCE

  • Punnett Squares provide a shorthand way of finding expected proportions of possible genotypes and phenotypes in the offspring of a cross.

  • Fertilization must occur at random

  • Results are expected, not actual; results based on chance

  • Results predicted by probability are more likely to be seen when there is a large number of offspring

  • a monohybrid cross contains four boxes; a cross between two heterozygous individuals would reveal a 1:2:1 genotype ration and a 3:1 phenotype ratio in the offspring; the probability that the offspring will show a dominant phenotype is ¾, or 75%

  • a dihybrid cross contains sixteen boxes; a dihybrid cross reveals two traits for both parents; a cross between two heterozygous individuals would reveal a 9:3:3:1 phenotype ratio in the offspring
    *KARYOTYPE: to identify gender or chromosomal abnormalities

NATURAL SELECTION and THEORY OF EVOLUTION

• proposed by Charles Darwin

• process by which organisms that are best suited to environment survive and pass genetic traits on to offspring

• has no effect on increased production of offspring, fossil formation, or changes in habitat

• adaptation – organisms with the most suited traits will survive

• evolution – change in a species over time (not a single individual, but the group)

  • microevolution – evolution that occurs within the species level; results from genetic variation and natural selection within a population

    • antibiotic resistance, pesticide resistance

  • macroevolution – evolution that occurs between different species; focuses on how groups of organisms change

    • convergent evolution – two species evolve similarly

    • divergent evolution – a group of species evolve differently

    • adaptive radiation – a group of species adapt separately to environments

    • speciation – formation of a new species

      • geographic isolation – physical barrier divides a population, results in individuals that cannot mate, leads to a new species

      • reproductive isolation – genetic mutation or behavioral change prevent mating

EVIDENCE OF EVOLUTION

• Fossils

  • may appear in rocks, ice, amber; when fossils are arranged in order of their age, the fossil record provides a series of changes that occurred over time; comparison of anatomical characteristics reveals shared ancestry
    DNA - when gene or protein sequences from organisms are arranged, species thought to be closely related based on fossil evidence are seen to be more similar than species thought to be distantly related

• Embryology - embryos of different vertebrates look alike in their early stages, giving the superficial appearance of a relationship

CLASSIFICATION

• process in understanding how organisms are related and how they are different

• taxonomy – branch of biology that studies grouping and naming of organisms

• history of classification systems

  • 4th Century B.C., Aristotle proposed two groups (plants and animals) and used common names for identification, based on “blood” and “bloodless”

  • early 1700s, Carolus Linnaeus developed a system based on physical characteristics

  • two kingdoms (plants and animals)

  • developed “genus” and “species”

  • designed system of naming called binomial nomenclature (“two names”) which gave each organism two names, a genus and a species, Genus always capitalized, both should be underlined or italicized

  • Six kingdoms: Archaebacteria, Eubacteria, Protista, Fungi, Plantae, and Animalia

  • a dichotomous key is a tool used to identify organisms by using pairs of contrasting characteristics

• basis of current classification: phylogeny, DNA / biochemical analysis, embryology, morphology, Phylogenetic trees

Levels of classification

• Kingdom

• Phylum

• Class

• Order

• Family

• Genus

• Species

Classification of humans

Kingdom-Animalia

• multicellular organisms that eat food

Phylum-Chordata

• dorsal hollow nerve cord, notochord, pharyngeal slits

Class-Mammalia

• hair, mammary glands, endothermy, four-chambered heart

Order-Primates

• nails, clavicle, orbits encircled with bone, enlarged cerebrum, opposable digits

Family-Homidae

• bipedal – walk erect on two feet, advanced tool use

Genus-Homo (“human” like)

Species-Homo sapiens.

Comparison of Eukaryote to Prokaryote:

Prokaryote:

• has nuclear material in the center of the cell, but is not enclosed by a nuclear membrane;

• no membrane bound organelles; examples: bacteria and blue-green algae

Eukaryote:

• contain a clearly defined nucleus enclosed by a nuclear membrane and membrane bound organelles; examples: plants, animals, fungi, and protists

Comparison of Eukaryote to Prokaryote:

VIRUSES (Note: Viruses are not considered living organisms!)

Structure and Replication

• Composed of a nucleic acid surrounded by a protein coat.

• Use living cells to replicate viral nucleic acid.

• Infects a living cell when the virus injects its nucleic acid into the host cell; the viral nucleic acid replicates and makes more viruses.

Infection Processes

• Two processes to infect host cells: the lytic cycle and the lysogenic cycle.

  • Lytic: Virus attaches to host cell, injects its nucleic acid; nucleic acid replicates immediately; host bursts, releasing the virus.

  • Lysogenic: Host infected but does not immediately die; viral DNA replicates with host DNA; virus becomes dormant, then spontaneously enters lytic cycle and cell bursts (may be years later).

Host Range and Treatment

• Viruses can infect animals, plants, and bacteria.

• Viruses do not respond to drug treatment.

• Immunity must be acquired naturally or from vaccinations.

DICHOTOMOUS KEYS

Device used to aid in identifying a biological specimen
Offers two alternatives at each juncture, each choice determining the next step; breaks down subgroups by their evolutionary relationships
Can be used for field identification of species, as found in field guides by focusing on practical characteristics
Example:

1. Leaves usually without teeth or lobes: 2

2. Leaves usually with teeth or lobes: 5

   2. Leaves evergreen: 3

   3. Leaves not evergreen: 4

   4. Mature plant a large tree — Southern live oak Quercus virginiana 3. Mature plant a small shrub — Dwarf live oak Quercus minima

   5. Leaves with 5-9 deep lobes — White oak Quercus alba

   6. Leaves with 21-27 shallow lobes — Swamp chestnut oak Quercus prinus
      Source: Wikipedia (http://en.wikipedia.org/wiki/Dichotomous_key )

Types of Plants and Animals:

Spore Producing Plants| Spore-Producing Plants Nonvascular, produce spores Remain small– absorb water by osmosis Sperm swim to fertilize eggs Live in moist environments Reproduce sexually Alternation of Generations (You see the gametophyte generation) Mosses and liverworts | Invertebrates No backbone, usually outer covering (exoskeleton) May be hydrostatic (water-based, aquatic) Sponges (Porifera) No symmetry Specialized bodily functions |

Vascular Plants Two types of vascular tissue Xylem – transports water and minerals (UP)Phloem – transports sugars (DOWN)Produce spores Club mosses, horsetails, ferns Require water for reproduction Alternation of Generations (you see the sporophyte generation) | No symmetry (disorganized) Radial symmetry (around a central point) Bilateral symmetry (equal on both sides) Three types of symmetry Specialized bodilyfunctions Cnidarians(Coelenterata) Jellyfish, hydrostatic, radial symmetry Specialized stinging cells in tentacles.Roundworms(Nematoda) Parasites, radial symmetry Segmented wormsearthworms decomposers Mollusks Food source Clams, oysters (bivalves) Hard outer shell (calcium carbonate Food source ArthropodsPollinators, bilateral symmetryCrabs, insects (segmented body Echinodermsstarfish radial symmetry Have a coelom (true body cavity) |

| Seede Producing Plant Seed = embryo protected by a seed coatTwo groups based on reproduction Gymnosperms – cone-bearing Angiosperms – flowering - monocots (corn) and dicots (flowers) Roots – anchor, absorb water, store food Stems – support, transport Leaves – photosynthesis, produces food Adaptations – seed, pollen, fruit,
flowers Pollination – fertilization, germination | Vertebrates
Skeletal systems (endoskeleton) Strong, flexible backbone (support)Bilateral symmetry Jawless fishes LampreysCartilaginous fishes Scales, paired fins, gills, bone External fertilizationBony fishes Bass, trout Amphibians Salamanders, frogs Moist skin and lack scalesExternal fertilization Reptiles Snakes, turtlesDry, scaly and Strong limbs| Birds Mammals|

REPRESENTATIVE GROUPS AND ESSENTIAL LIFE FUNCTIONS: