Cell Types and Organelles. Biology. Organic Compounds. Characteristics of Life:

Size: px

Start display at page:

Download "Cell Types and Organelles. Biology. Organic Compounds. Characteristics of Life:"

Branden Johnson
6 years ago
Views:

Biology Characteristics of Life: 1. Living things are composed of cells. 2. Living things have different levels of organization. 3. Living things use energy. 4.

Organic Compounds Organic Compounds: A compound is a combination of 2 or more atoms. An organic compound is a compound that contains carbon atoms that have combined with each other.

2. Lipids: Fats and oils used for long term energy & insulation. 3. Proteins: Made up of amino acids; used for construction materials and chemical reactions in the body.

Cell Types and Organelles Cell - is the smallest unit that is alive and can carry on all the processes of life. Prokaryotic: cell that does not have a nucleus or other membrane-bound organelles.

Organelle Function Plant Animal Bacteria Nucleus Mitochondria Endoplasmic Reticulum Golgi body Ribosome Lysosome Cell Membrane Cell Wall Chloroplast Vacuole Cytoplasm Controls center; contains

1 Biology Characteristics of Life: 1. Living things are composed of cells. 2. Living things have different levels of organization. 3. Living things use energy. 4. Living things respond to their environment. 5. Living things adapt, grow and reproduce. 6. Living things reproduce. 7. Living things adapt to their environment. Organic Compounds Organic Compounds: A compound is a combination of 2 or more atoms. An organic compound is a compound that contains carbon atoms that have combined with each other. An inorganic compound is a compound with no combination of carbon atoms. The Four Types of Organic Compounds The Molecules of Life: 1. Carbohydrates: Sugars (saccharides) used for short term energy. 2. Lipids: Fats and oils used for long term energy & insulation. 3. Proteins: Made up of amino acids; used for construction materials and chemical reactions in the body. DNA holds the message for making all proteins. o Enzymes: Special types of proteins that speed up (catalyze) chemical reactions in the body but are not changed by the reactions. Cell Types and Organelles Cell - is the smallest unit that is alive and can carry on all the processes of life. Prokaryotic: cell that does not have a nucleus or other membrane-bound organelles. Unicellular. Eukaryotic: cell that has a nucleus and other membrane-bound organelles. Uni/Multicellular. Organelles: specialized structures that carry out a specific function (job). Organelle Function Plant Animal Bacteria Nucleus Mitochondria Endoplasmic Reticulum Golgi body Ribosome Lysosome Cell Membrane Cell Wall Chloroplast Vacuole Cytoplasm Controls center; contains chromosomes made of DNA Cell respiration; provides energy, power and heat (ATP) Transports substances through the cell Sorts, modifies, cell products/proteins Protein synthesis/makes proteins Contains digestive enzymes to break down and digest waste and old organelles Maintains homeostasis by controlling what enters and leaves the cell. Protection. Support and Protection Traps sunlight to make food for the plant through Photosynthesis Stores water. Suspends organelles in a cell; enclosed within the cell membrane 4. Nucleic acids: DNA and RNA; contains genetic information and instructions for making proteins.

Cell Membrane Types of solutions: -Made up of biomolecules called phospholipids (fats that don t like water). -Phospholipid bilayer is the 2 layers of phospholipids that make up the cell membrane.

Hypertonic solutions cause water to move out of the cell causing the cell shrivel or die.

Cellular Transport Homeostasis: ability of cell, system, organism to maintain stable internal equilibrium. (temperature, ph, water content).

2 Cell Membrane Types of solutions: -Made up of biomolecules called phospholipids (fats that don t like water). -Phospholipid bilayer is the 2 layers of phospholipids that make up the cell membrane. -Selectively permeability, which means that it allows some, but not all materials to cross. Hypotonic solutions cause water to move into the cell causing the cell to swell. Hypertonic solutions cause water to move out of the cell causing the cell shrivel or die. Isotonic solutions cause water molecules to move into and out of the cell at an equal rate; cell size does not change. Cellular Transport Homeostasis: ability of cell, system, organism to maintain stable internal equilibrium. (temperature, ph, water content). Cell Transport: movement of molecules across the cell membrane. Transport through the Cell Membrane Transport Movement of molecules Requires Energy from Cell? Passive High to low concentration No Active Low to high concentration Yes Passive transport: requires no energy, moves with concentration gradient (high to low). MEASUREMENT Cellular Energy Photosynthesis: radiant energy from the sun is used by producers to join carbon dioxide and water to make food (glucose); process takes place in the chloroplast. Photosynthesis: 6CO2 + 6H2O C6H12O6 + 6O2 Cellular Respiration: mitochondria break down food molecules (glucose) to produce cell energy (ATP). Diffusion: movement of molecules from high to low concentration. Osmosis: diffusion of water across a selectively permeable membrane, from high to low, until equilibrium is reached. Facilitated diffusion: the movement of molecules from high to low concentration, but requires a channel protein to help the molecule across. Cellular Respiration: Photosynthesis Cellular Respiration C6H12O6 + 6O2 6CO2 + 6H2O + ATP (energy) Reactant(s) Product(s) Organelle Involved -Carbon -Glucose dioxide (CO 2) (C 6H 12O 6) Chloroplast -Water (H 2O) -Oxygen (O 2) Glucose (C 6H 12O 6) -Oxygen (O 2) -Carbon dioxide (CO 2) -Water (H 2O) -ATP Mitochondria ATP: made of adenosine molecule, ribose sugar, and three phosphate groups; all held together by chemical bonds. ATP Cycle: Remember that when bonds are made = ENERGY STORED When bonds are broken = ENERGY RELEASED So the way energy is stored and released with ATP is to add or remove a phosphate. Active transport: requires energy, moves against the concentration gradient (low to high)..

Cell Cycle The cell cycle is the phases in the life of a cell consisting of cell growth and division: DNA and Replication Nucleotides: structures that make up nucleic

M: Division of a cell into 2 identical daughter cells (PMAT) Sugar Bases Base Pairs Shape Function DNA Deoxyribose Adenine, Thymine, Guanine, Cytosine A T C G Double Helix

- Diploid two sets of chromosomes 2n Before mitosis: Chromosomes have copied themselves.

Replication: the process used by cells to copy DNA; takes place during the S phase of the cell cycle.

The enzyme, DNA Polymerase, bond the new nucleotides together.

3 Cell Cycle The cell cycle is the phases in the life of a cell consisting of cell growth and division: DNA and Replication Nucleotides: structures that make up nucleic acids (DNA/RNA) Phase Interphase Mitosis Steps in Phase G1: intense growth and enzyme production S: DNA synthesis/replication G2: growth and preparation for cell division. M: Division of a cell into 2 identical daughter cells (PMAT) Sugar Bases Base Pairs Shape Function DNA Deoxyribose Adenine, Thymine, Guanine, Cytosine A T C G Double Helix Codes for proteins/rna Process starts with diploid cells and ends with diploid cells. - Diploid two sets of chromosomes 2n Before mitosis: Chromosomes have copied themselves. Sister chromatids: original chromosome and its exact copy are attached to each other. Replication: the process used by cells to copy DNA; takes place during the S phase of the cell cycle. The enzyme, Helicase, unzips DNA and each side of the ladder acts as a template for the building of the new half. The enzyme, DNA Polymerase, bond the new nucleotides together. EX) TACGGAC (old strand) ATGCCTG (new strand Phases of mitosis Cell Specialization: DNA holds the genetic information that controls what a cell can do and what molecules it can make. Example: White blood cells in animals are specialized to attack pathogens like viruses or bacteria. DNA RNA Sugar Deoxyribose Ribose Bases Adenine, Thymine, Adenine, Uracil, Guanine, Cytosine Guanine, Cytosine A T A U Base C G C G Pairs Shape Double Helix Single Strand Function Codes for proteins/rna Copy of DNA information for transcription Cell Differentiation: process by which a cell becomes specialized for a specific structure or function during multicellular development.

Protein Synthesis Mutations and Genetic Variations Mutation: genetic change in DNA. There are many kinds of mutations that occur at different levels, but they all change DNA.

Point mutations effect single bases Substitution Transcription: process that copies DNA s genetic information into messenger RNA: 1. DNA strands temporarily unwind. 2.

EX) TACGGAC (template DNA strand) AUGCCUG (RNA built) Codon: formed from a sequence of three nucleotides (like AAA or GAC); different codons specify one of twenty different amino acids.

Frameshift mutations shift the reading frame of the DNA. Insertion Deletion Mutations can be harmful, beneficial or have no effect on the organism.

4 Protein Synthesis Mutations and Genetic Variations Mutation: genetic change in DNA. There are many kinds of mutations that occur at different levels, but they all change DNA. At the DNA level during Replication. At the Chromosome level during Meiosis and Mitosis. Point mutations effect single bases Substitution Transcription: process that copies DNA s genetic information into messenger RNA: 1. DNA strands temporarily unwind. 2. Complementary RNA nucleotides pair up with one strand of DNA nucleotides. 3. Messenger RNA (mrna) carries specific protein synthesis instructions to ribosomes. EX) TACGGAC (template DNA strand) AUGCCUG (RNA built) Codon: formed from a sequence of three nucleotides (like AAA or GAC); different codons specify one of twenty different amino acids. Translation: process by which a protein is made from mrna; occurs within a cell s ribosomes; trna (transfer RNA) matches codons to amino acids which then join together to form a protein chain. Frameshift mutations shift the reading frame of the DNA. Insertion Deletion Mutations can be harmful, beneficial or have no effect on the organism. A mutation that changes codon AAA to codon AAG (substitute G for the last A) likely has no effect because AAA and AAG both code for Lysine. A mutation that results in codon UAA would likely result in an observable change because UAA is a stop codon. Meiosis: Cell division that produces gametes (sex cells), such as sperm and egg cells. Protein: molecule made of amino acids that performs a specific task. Transcription Translation Haploid cell with half the number of chromosomes - n Steps in meiosis 1. Before meiosis: 2 chromosomes of the same type come together to make a chromosome pair. Each chromosome doubles (DNA replication during S phase of Interphase). This gives 4 chromosomes stuck together. 2. Meiosis I: Chromosome pairs separate into two new cells- PMAT Codon Chart 3. Meiosis II: Each chromosome separates from its copy into 4 new cells- PMAT In meiosis, one cell becomes four non-identical daughter cells. BUT in mitosis, one cell becomes two daughter cells. Chromosomes: DNA strands in the nucleus that contain the directions on how to make and keep an organism alive. Copied and passed from parent to offspring. Crossing over occurs during Meiosis, pieces of chromosomes are exchanged.

Fertilization: Process of an egg and a sperm cell combining to produce a zygote, both haploid cells.

1. Law of Segregation: alleles segregate and recombine; one allele is inherited from each parent. 2. Law of Dominance: one trait may mask (dominant) the effect of another trait. 3.

Monohybrid Cross: One trait G = dominant allele for yellow g = recessive allele for green Autosomes: Chromosomes that do not determine gender (chromosomes 1 through 22) Sex chromosomes: Chromosomes

GENETICS Genetics: the study of heredity. Gregor Mendel is an Austrian monk credited with beginning the study of genetics. Gene: segment of DNA; controls specific traits.

Dominant gene: Allele that is expressed when two different alleles are present in an organism s genotype. Represented by a capital letter.

5 Fertilization: Process of an egg and a sperm cell combining to produce a zygote, both haploid cells. Zygote: Baby that is only 1 cell big Human egg cell (23 chromosomes) + Human sperm cell (23 chromosomes) = baby (46 chromosomes) Mendelian Genetics: Laws regarding the inheritance of genetic traits: 1. Law of Segregation: alleles segregate and recombine; one allele is inherited from each parent. 2. Law of Dominance: one trait may mask (dominant) the effect of another trait. 3. Law of Independent Assortment: allele for a trait segregate and recombine independently of other traits; example: height and eye color do not influence each other. Monohybrid Cross: One trait G = dominant allele for yellow g = recessive allele for green Autosomes: Chromosomes that do not determine gender (chromosomes 1 through 22) Sex chromosomes: Chromosomes that determine gender (chromosome 23) Females are XX, Males are XY Dihybrid Cross: two traits G and R = dominant allele for yellow and round g and r = recessive allele for green and wrinkled. GENETICS Genetics: the study of heredity. Gregor Mendel is an Austrian monk credited with beginning the study of genetics. Gene: segment of DNA; controls specific traits. Humans have 2 genes for every trait. Heredity: passing on of characteristics from parents to offspring. Alleles: Different forms of a single trait, like blue and brown are two eye color alleles. Dominant gene: Allele that is expressed when two different alleles are present in an organism s genotype. Represented by a capital letter. Recessive gene: Allele that is expressed only when two copies are present. Represented by a lowercase letter. Non-Mendelian Inheritance: inheritance pattern that does not follow Mendelian genetics law. Incomplete Dominance: One allele is NOT completely dominant over the other. R = dominant (incomplete) allele for red flower r = recessive allele white flower Homozygous (purebred): When 2 genes are alike for a trait. BB is homozygous dominant; bb is homozygous recessive. Heterozygous (hybrid): When 2 genes are different for a trait. Bb is heterozygous. Phenotype: The physical appearance of an organism (Brown eyes), like a picture - what it looks like on the outside. Genotype: Includes both of the genes that code for a trait; represented by the letters. Example: BB, Tt, Rr Co-Dominance: Both alleles are dominant; both alleles are expressed. R = dominant allele for red coat W = dominant allele for white coat

Sex-Linked Inheritance: Allele for a trait is carried on only one of the sex chromosomes. The gene for male-pattern baldness is linked to the x chromosome.

inherited trait that gives and advantage to individual organisms and is passed on to future generations. Traits: Characteristic that is inherited.

6 Sex-Linked Inheritance: Allele for a trait is carried on only one of the sex chromosomes. The gene for male-pattern baldness is linked to the x chromosome. X B = female sex chromosome with dominant baldness allele X b = female sex chromosome with recessive baldness allele (carrier) Y = male sex chromosome does not carry baldness allele Adaptation: inherited trait that gives and advantage to individual organisms and is passed on to future generations. Traits: Characteristic that is inherited. Behavior: the way an organism moves, functions or reacts. Behavior Description Example Inherited Born with it; not learned Breathing Learned Not born with it; must learn Reading Evidences of Evolution 1. Fossil Record: preserved remains or traces of organisms. 2. Homologous Structures: same basic structure formed from same embryonic tissue. Biotechnology DNA Fingerprinting: process of identifying the location of base pairs at certain locations on the DNA for comparison to a known sample. Gel Electrophoresis: is a process of passing DNA fragments through agar gel to separate the fragments by size. Karyotypes: pictures of chromosomes that can be counted and sorted. Chromosomes from a single cell are isolated in a solution and used to create the Karyotype, which can determine if a person has an abnormal number of chromosomes and the location of the abnormality Nondisjunction mutations: (monosomy and trisomy) can result in Down Syndrome, Kleinfelter s Syndrome and Turner s Syndrome 3. Analogous Structures: same basic functions due to same environmental pressures. 4. Embryology: embryos of various species appear identical. Genetic Recombination: At times, either biologically or artificially, it is useful to combine certain segments of DNA from other organisms. Evolution and Natural Selection Evolution: Genetic change in a species over time. Changing of a species (not an individual s) traits over many, many years; natural selection is a mechanism for evolution. 5. Molecular Homology: DNA and protein amino acid sequence comparisons. Strongest evidence for Evolution. EX: the human genome and the chimpanzee genome are approximately 99% identical. 6. Biogeography: geographic distribution of organisms; species that live in the same area are more closely related, but related species can also be found living far apart. Natural Selection: process by which organisms with certain favorable traits survive and reproduce more successfully than others; causes change in populations (NOT individuals) and affects the diversity of a species. Example: insects that are resistant to insecticide are more likely to survive and reproduce.

Evolutionary Mechanism Genetic Drift Description Change in green pool caused by chance. EX: catastrophic event; flood, volcano, mass isolation of groups, hunting.

Genus species Ex: Homo sapien human INTO population Phylogenetic Tree: diagram taxonomist use to show evolutionary relationships among species Gene Flow Change in gene pool caused by organisms

7 Evolutionary Mechanism Genetic Drift Description Change in green pool caused by chance. EX: catastrophic event; flood, volcano, mass isolation of groups, hunting. Effect on Genetic Variation Binomial Nomenclature: modern classification system using a two-word (genus and species) naming system; written in italics. Genus species Ex: Homo sapien human INTO population Phylogenetic Tree: diagram taxonomist use to show evolutionary relationships among species Gene Flow Change in gene pool caused by organisms gradual movement into or out of the population. OUT of population Mutation Change in gene pool caused by insertion, deletion, or substitution of DNA sequence of gamete cell. Recombination Change in gene pool caused by exchange of genetic sequence during gene crossover events during Prophase I of meiosis. Taxonomy & Classification Taxonomy: the study of the methods of man-made classification systems. Classification: way of organizing information by putting objects or ideas into groups based on similarity. Enables us to study relationships and differences Cladogram: diagram based on patterns of shared, derived traits that shows the evolutionary relationship between groups of organisms. Example: Man s best friend, the dog. General Specific Kingdom Archaebacteria Ex: halophiles, methanogens Eubacteria Ex: bacteria, algae Protists Ex: amoebas, paramecium Kingdom Phylum Class Order Family Genus Species Fungi Ex: yeasts, mushrooms Plantae Ex: mosses, ferns, trees Animalia Ex: worms, fish, insects, bird, dog Animalia Chordata Mammalia Carnivora Canidae Canus lupus Characteristics prokaryotic, cell wall, no nucleus; lives in extreme environments prokaryotic, cell wall, no nucleus; autotrophs or heterotrophs eukaryotic, nucleus and cell membrane; autotrophs or heterotrophs eukaryotic, cell wall, nucleus, cell membrane; no chloroplasts, heterotrophs eukaryotic, cell wall, nucleus, cell membrane, chloroplasts, autotrophs eukaryotic, nucleus, cell membrane, heterotrophs Dichotomous Key: Guide used to identify organisms. Uses pairs of observable traits as a checklist to pinpoint the organism s identity.

VIRUSES AND BACTERIA Virus: microscopic (smaller than bacteria) nonliving particle that can only reproduce in host cell and causes diseases/conditions like smallpox, colds, influenza (flu), HIV,

Internal Feedback Mechanisms: self-regulating process, like a chemical reaction, that can help maintain homeostasis. Positive Feedback: increases the effect in response to a stimuli.

Once blood clotting starts it sends information for more clotting factors. Is made up of a capsid head/protein coat (containing DNA or RNA) and a tail that attaches to the host cells.

8 VIRUSES AND BACTERIA Virus: microscopic (smaller than bacteria) nonliving particle that can only reproduce in host cell and causes diseases/conditions like smallpox, colds, influenza (flu), HIV, warts Homeostasis: the regulation and maintenance of constant internal conditions in and organism. Internal Feedback Mechanisms: self-regulating process, like a chemical reaction, that can help maintain homeostasis. Positive Feedback: increases the effect in response to a stimuli. EX: blood clotting after a cut. Blood clotting happens once the sensory for it has been triggered and the brain sends information to start blood clotting. Once blood clotting starts it sends information for more clotting factors. Is made up of a capsid head/protein coat (containing DNA or RNA) and a tail that attaches to the host cells. Host: a living cell in which a virus reproduces. Comparison Virus Cell Classification Nonliving Living Structure Head has nucleic acids surrounded by protein coat Has nucleic acids, ribosomes, cytoplasm, etc. Metabolism None; depends on Makes own Reproduction host cell Needs host cell; does not grow proteins Divides into two similar cells after growth Negative Feedback: decreases the effect in response to a stimuli. EX: maintenance of normal body temperature. Interactions Among Systems in Plants and Animals Function Regulation Nutrient Absorption Reproduction Defense Function Transport Reproduction Response Interactions Among Systems in Animals Examples of Interactions The endocrine system makes hormones. Blood in the circulatory system carries the hormones to the skeletal system to control the amount of calcium released from bones. Food is broken down in the stomach mechanically by the muscular system and chemically by water, acid, and enzymes in the digestive system. Nutrients are then absorbed by blood in the circulatory system. Certain hormones produced in the endocrine system control ovulation in the female s reproductive system. Mucus in the lungs traps a virus in the respiratory system. T-cells in the immune system destroy virusinfected cells. Nerves in the nervous system sense the need to cough. Interactions Among Systems in Plants Examples of Interactions The roots uptake water. Xylem tissues transport water to the leaves. Phloem tissue transport sugar and nutrients throughout the plant. The reproductive organs in a flower are the pistil (female) and the stamen (male). A seed is a mature, pollinated ovule (fertilized egg). Hormones in a plant s roots help trigger the growth of a seed. If light hits on one side of a stem, auxins (hormone) will build up in the cells on the shaded side of the stem. These cells then elongate and grow longer, causing the stem to bend toward the light. Ecology Living things are affected by biotic and abiotic things in the environment Abiotic factor: the nonliving parts of an organism s environment. EX: air currents, temperature, light, and moisture Have effects on living things and often determine which species can survive in an area. Biotic factor: the living things that inhabit an environment. EX: plants, animals, fungus, bacteria all organisms depend on others directly or indirectly for food, shelter, reproduction, or protection Levels of Organization Species Population Community Ecosystem Biosphere Species: a group of similar organisms that can interbreed and produce fertile offspring. Population: a group of the same species, that lives in one area. Members of the same population may compete with each other for resources. Some may have adaptations to reduce competition.

Community: a group of different species that live together in one area. EX: a group of alligators, birds, fish, and plants that live together in Armand Bayou.

Ecosystem: includes all of the organisms as well as the climate, soil, water, rocks and other nonliving things (abiotic factor) in a given area.

9 Community: a group of different species that live together in one area. EX: a group of alligators, birds, fish, and plants that live together in Armand Bayou. A change in one population in a community may cause changes in the other populations. Ecosystem: includes all of the organisms as well as the climate, soil, water, rocks and other nonliving things (abiotic factor) in a given area. Types of ecosystems: Terrestrial ecosystems located on land (forest, meadow) Aquatic ecosystem freshwater (ponds, lakes, river) and saltwater (ocean, marine) Ecosystem Stability: changes in the environment, caused by nature or humans, can affect the stability of an ecosystem in positive or negative ways. Environmental changes can help sustain diverse and abundant populations over a long period of time, or they can diminish or destroy populations. EX: Human Impacts including air/water pollution or conservation Limiting Factors: conditions that control a population s size (food, water, living space, disease, predators, etc.). Carrying Capacity: maximum population that can live in area over given period of time; controlled by limiting factors. Roles of Organisms Nutrition and Energy Flow The ultimate source of energy for life is the sun! Autotroph/Producers: an organism that uses the suns energy to make food energy in a process called photosynthesis. EX: grass, trees, green algae Heterotroph/Consumer: an organism that must obtain nutrients by eating others. Herbivores Only feed on autotrophs; eats plants. Carnivores Only feed on other heterotrophs (meat). Scavengers Eat animals that have already died. Omnivores Eat autotrophs and other heterotrophs. Decomposers Break down the complex compounds of decaying plant and animals. Community Interactions Mutualism a relationship in which both species benefit. +/+ A bee pollinating a flower. Commensalism a relationship in which one species benefits and the other species is unaffected. +/ Barnacles on a whale. Parasitism a relationship in which a member of one species benefits at the expense of another species (the host). +/- Heartworms in a dog. Energy in an Ecosystem Matter, in the form of carbon, nitrogen, and other elements, flow through the levels of an ecosystem from producers to consumers. Food Chain: shows how energy and matter move from one organism to another; energy originates from Sun; arrows show the direction of energy flow. Food Web: shows many food chains in an ecosystem; size limited by amount of energy that can be transferred. Trophic Levels: classification of organisms by feeding relationships; organisms (like omnivores) may appear in multiple levels. Level Description Example Energy First Producer Plants Most Second Primary consumer Herbivores Third Secondary consumer Carnivores that eat herbivores Fourth Tertiary consumer Carnivores that eat carnivores Least Energy Pyramid: shows how energy is lost from one trophic level to the next (energy for metabolism etc.); only about 10% of energy transfers to next level; therefore approximately 90% is lost as heat. Max of 4 to 5 trophic levels per pyramid; energy moves in one direction only (not recycled). Biological magnification: The increasing concentration of a substance, such as a toxic chemical, in the tissues of organisms at higher levels in a food chain. As a result of biomagnification, organisms at the top of the food chain generally suffer greater harm from a persistent toxin or pollutant than those at lower levels. Role of Microorganisms Beneficial Bacteria: helpful bacteria are used to make yogurt, cheese, and drugs like insulin; decompose and recycle nutrients (nitrogen cycle); help absorb nutrients during digestive process; used to tan leather; etc. Harmful Bacteria: harmful bacteria can spoil food or cause diseases like streptococcus (strep throat).

Cycles in Nature Carbon Cycle: the movement of carbon through the environment.

Animals eat plants and use this carbon for cellular respiration.

Bacteria change the atmosphere s nitrogen gas (N2) into a usable form, like nitrates.

10 Cycles in Nature Carbon Cycle: the movement of carbon through the environment. Plants use CO2 to make sugars and starches via photosynthesis. Animals eat plants and use this carbon for cellular respiration. Nitrogen Cycle: constant movement of nitrogen through the environment. Bacteria change the atmosphere s nitrogen gas (N2) into a usable form, like nitrates. Plants uptake nitrates from the soil; plants are then eaten by animals. Decomposers return nitrogen to the soil by breaking down dead organisms and/or waste. Denitrifying bacteria change nitrogenous compounds back to N2 Ecological Succession:

THINGS I NEED TO KNOW:

THINGS I NEED TO KNOW: 1. Prokaryotic and Eukaryotic Cells Prokaryotic cells do not have a true nucleus. In eukaryotic cells, the DNA is surrounded by a membrane. Both types of cells have ribosomes. Some