All living cells can be divided into two groups: • Prokaryotic cells – simple cells – Single-celled organisms (bacteria and blue-green algae) • Eukaryotic cells – more complex cells – Single-celled organisms (protists) – Compose multi-cellular organisms (protists, fungi, plants and animals)
Feature Function Prokaryotes Eukaryotes Cell (plasma) Regulate material entering All All membrane and exiting cell DNA Stores genetic material All All Cell wall Protect cell, provide shape All Some (plants) Cytoplasm Fluid inside cell All All Nucleus Houses DNA None All Ribosomes Site of protein synthesis All All Flagella Aid cell in locomotion Some Some Mitochondria Site of ATP synthesis None All Endoplasmic Synthesis of proteins and None All Reticulum lipids Golgi Storage and packaging of None All apparatus substances Lysosomes & Digest particles None All Peroxisomes Vacuoles Storage of material Some Some Plasmids Small pieces of DNA that Some None can exit the cell Plastids Contain food or pigments None Some (plants)
Biology 4A Prokaryotes & Eukaryotes
Prokaryotic Bacterial Cell
Eukaryotic Plant Cell Eukaryotic Animal Cell
Biology 4A Cellular Processes
Energy conversions Photosynthesis – conversion of radiant energy (sunlight) into chemical energy (glucose), occurs in chloroplasts of autotrophs
6CO2 + 6H2O + energy → C6H12O6 + 6O2 Chemosynthesis – conversion of unusable chemical energy (methane) into usable chemical energy (carbohydrates) Adenosine triphosphate (ATP) – molecule which living things use to release and store energy, becomes adenosine diphosphate (ADP) when energy is released
Glycolysis – process of producing 2 ATP by breaking down glucose into pyruvic acid, first step of respiration Aerobic respiration – respiration in which, after glycolysis, pyruvic acid is broken down into carbon dioxide and water, net gain of 36 additional ATP Anaerobic respiration – respiration in which, after glycolysis, pyruvic acid is broken down into either lactic acid or alcohol, does not provide ATP, allows glycolysis to continue
Biology 4B Cellular Processes
Synthesis of New Molecules DNA Replication 1. Helicases unwind and unzip DNA at replication forks 2. Free floating nucleotides bond to exposed bases 3. DNA polymerase bind nucleotides to each other in 5’ to 3’ direction a. Leading strand – elongates toward replication fork continuously b. Lagging strand – elongates away from replication fork discontinuously (called Okazaki fragments), bonded together by DNA ligase 4. New molecules each contain one original and one new strand
Transcription – process by which a portion of DNA nucleotide sequence is used to produce a complementary mRNA strand by RNA polymerase Translation – process by which information in mRNA strand is used to create amino acid chain (polypeptide chain) by ribosomes and tRNAs Lipogenesis – process of synthesizing lipids from intermediates of cellular respiration, occurs along smooth endoplasmic reticulum
Biology 4B Cellular Processes
Transport of Molecules Intracellular transport – within the cell • Many molecules float freely through cytoplasm • Others are carried by motor proteins (kinesin) or the endoplasmic reticulum and Golgi apparatus Intercellular transport – in and out of the cell through plasma membrane Passive transport – does not use energy, movement down concentration gradient (high to low concentration) • Diffusion – net movement of small, nonpolar molecules directly through phospholipid bilayer • Facilitated diffusion – net movement of larger molecules and ions through ion channels or carrier proteins • Osmosis – net movement of water molecules through membrane
Active transport – uses energy (ATP), movement up concentration gradient (low to high concentration) • Ion pumps – proteins that move ions one way • Cotransport – coupled passage of two molecules in the same direction (symport) or different directions (antiport)
Homeostasis – ability of a cell to maintain stable internal conditions independent of environment, accomplished by passive and active transport • Carbonic acid – buffer that helps regular pH
Biology 4B Biology 4C - Viruses
Parts of Viruses capsid bacteriophage animal virus
membranous tail envelope
tail fibers
Viruses vs. Cells Viruses Cells
DNA or RNA Only DNA
Need host for replication Can reproduce independently
Never contain organelles Can contain organelles
Do not convert energy Convert energy
Replication Cycles
Lytic Lysogenic
Biology 4C Biology 4C - Viruses
Human Viral Diseases
AIDS • Loss of immune system effectiveness • Caused HIV - human immunodeficiency virus • Period of dormancy before loss of immune system • Prevention • No vaccine (yet) • Limit and avoid transmission
Influenza (the flu) • Fever, fatigue, and respiratory infections • Can be deadly • Caused a variety of influenza viruses • Can mutate rapidly and blend together • Prevention • Seasonal vaccine • Limit transmission
The Common Cold • Fever, fatigue, and respiratory infections • Caused a variety of rhinoviruses • Prevention • No vaccine • Limit transmission
Hepatitis A • Inflammation of liver, jaundice (yellow) appearance • Caused a hepatitis A virus in food and water • Prevention • Vaccine • Limit transmission
Biology 4C Cell Cycle
Cell cycle – the sequence of cell growth and division that occurs in a cell between the beginning of one cell division and the beginning of next cell division • Interphase (G1, S, G2) – period in which cell prepares for division. DNA and organelles replicate. • Mitotic phase (mitosis and cytokinesis) – period in which cell divides into two daughter cells. Ensures that daughter cells receive correct number of chromosomes.
Biology 5A Cell Cycle
Mitosis – the process by which each daughter cell receives an exact copy of chromosomes present in parent cell • Prophase – chromatin coils into chromatid, centrioles move apart, spindle fibers form • Metaphase – chromosomes arranged along spindle equator by spindle fibers, centromeres attach to separate spindle fibers • Anaphase – spindle fibers shorten and pull chromatids apart at the centromere • Telophase – chromatids reach opposite poles, spindle fibers disappear, nuclear membrane forms, chromosome uncoil
Cytokinesis – the division of the cell’s cytoplasm into two daughter cells • Animal cell – cell membrane pinches together, groove forms until membrane separates • Plant cell – cell plate extends outward until it divides cells
Biology 5A Cell Cycle
DNA replication – the process by which DNA is copied into a new strand, occurs during S phase of interphase • Semiconservative replication – each new molecule contains one original and one new strand • Helicase unwinds DNA and break hydrogen bonds between complementary base pairs o Replication fork – site which separation occurs • Free-floating nucleotides bond to exposed bases (A & T, C & G) • DNA polymerase bond nucleotides to each other in 5’ to 3’ direction o Leading strand: elongates continuously toward replication fork o Lagging strand: elongates discontinuously as Okazaki fragments away from replication fork, sealed by DNA ligase
Why is the cell cycle important? • Cells are limited in size. Large organisms need to be multicellular. Proper cell division ensures daughter cells have correct DNA • Mode of reproduction for unicellular organisms • Mode of growth, maintenance, and replacement for multicellular organisms
Biology 5A Specialized Cells
Specialized Plant Cells Cell Feature Function Concentric circles of Transport water and Root cells vascular tissue minerals upward Hairs protruding from cell Absorb water and minerals Root cells walls from soil Concentric circles of Transport water and Stem cells vascular tissues minerals throughout plant Thick-walled cells around Stem cells Provides support outer edge Cells have many Leaf cells chloroplasts, arranged in Carry out photosynthesis layers
Specialized Animal Cells Cell Feature Function Deliver oxygen to body Red blood cells Contain hemoglobin cells Contain filaments that can Cause movement of body Muscle cells contract parts or substances Epithelium cells Cells packed tightly Form a protective cover (exterior skin) together Epithelium cells High surface area Exchange molecules (internal lining) Contain dendrites and Transmit electrical signals Nerve cells axon throughout body
Biology 5B Cell Differentiation
Stem cells – cells that can differentiate into a variety of specialized cell types
Specialized cells – cells with specific structure and function • Examples: blood cells, leaf cells
Cell differentiation – process of converting stem cells into more specialized cell types in multicellular organisms
How does cell differentiation occur? • Proteins are produced by the cell – Direct the modification of the cell’s structure – Allow the cell to begin carrying out specialized functions • Role of DNA – Segments not needed are coiled tightly around histones – Segments needed are transcribed into proteins • Role of RNA – mRNA transcript used to create protein during translation – Small RNA remove introns from mRNA strands • Change the protein produced – Small RNA can bind and degrade mRNA strands • Stop protein from being produced • Role of environment – Neighboring cells can send signaling proteins to alter gene expression – Temperate can alter gene expression – Low oxygen concentration can suppress gene expression
Biology 5C Cell Cycle and Cancer
Cell cycle – the sequence of cell growth and division that occurs in a cell between the beginning of one cell division and the beginning of next cell division • End of G1 – vital checkpoint, cell determines whether or not to replicate its DNA o Mutations in growth- regulating genes cause cells to divide more rapidly
Growth regulating genes Proto-oncogenes – encode proteins that stimulate cell division in normal cells • Mutation Oncogenes – mutated proto-oncogenes that speed up cell division Tumor suppressor genes – encode proteins that turn off cell division in normal cells • Mutation Mutated suppressor genes fail to turn off cell division
Tumors and cancer Tumor – dense mass of abnormal cells • Result of mutations in growth-regulating genes • Benign – localized tumor, cells do not invade other tissues • Malignant – cells of tumor do not remain in one area, migrate and invade other tissues Cancer – condition in which malignant cells invade and destroy body tissues • Develops overtime due to genetic changes • Can be stimulated by carcinogens
Biology 5D DNA
Components of DNA Deoxyribonucleic acid (DNA) is a double-stranded macromolecule, made of building blocks called nucleotides Each nucleotide contains a • Phosphate base • Deoxyribose sugar • Nitrogenous base
Bonding in DNA • The sides of one DNA molecule is connected with bonds between the phosphate group and the deoxyribose sugar • The two DNA strands connect by bonds between nitrogenous bases o A always bonds with T o G always bonds with C
Role of DNA DNA is the genetic material of organisms. • Information coded in the order of the bases used to create proteins • Proteins act as enzymes, cell signals, and structural elements, contributing to the traits seen in organisms. • Different DNA can lead to different proteins
Biology 6A The Universal Genetic Code
Genetic code – the rules by which information in genetic material is translated into proteins • Universal – almost all living things use the same translation rules (the same mRNA strand would be translated into the same protein in different organisms) • Rules can be summarized into a codon chart
Components of the genetic code • DNA – stores the sequence of nucleotides • RNA – carries the nucleotide sequence to the cytoplasm, aids in translation
Biology 6B Transcription & Translation
How is DNA used to create proteins? 1) Transcription – process by which DNA is used to produce mRNA a) RNA polymerase – protein that initiates and operates transcription b) mRNA – messenger RNA, carries information into cytoplasm
Use the steps below to determine an mRNA strand sequence.
2) Editing and processing – process of modifying mRNA in eukaryotes a) introns removed b) exons spliced together c) cap and tail added d) sent out of the nucleus
Biology 6C Transcription & Translation
How is DNA used to create proteins (cont.)? 3) Translation – process by which information in mRNA strand is used to create amino acid chain (polypeptide chain) a) Ribosome – protein complex where translation occurs, made of rRNA b) tRNA – transfer RNA, bring amino acids to the ribosome
Use the steps below to determine a polypeptide chain sequence.
4) Editing and folding a) editing – sections of polypeptide chain removed b) folding – chain folds to make 3D shape, critical for protein function
Biology 6C Regulation of Gene Expression
Gene regulation occurs at all four levels of gene expression
Condensed DNA less likely to be used, transcription factors promote or suppress transcription
Modification (splicing) of initial mRNA transcript into mature transcript changes protein
Proteins limit export of mature mRNA from nucleus to cytoplasm
mRNA structure and proteins affect initiation, environmental factors increase or decrease translation
Biology 6D DNA Mutations
Mutation – a random change in the sequence of a gene, caused by mistakes in DNA replication process and environmental agents. Mutation Definition Example Point mutation One base replaced with another base ABCDEFG (Substitution) ABZDEFG Inversion Order of two or more bases reversed ABCDEFG ABEDCFG
Insertion Addition or one or more new bases ABCDEFG ABCHDEFG Deletion Removal or one or more bases ABCDEFG ABEFG CD Translocation Movement of one or more bases to a ABCDEFG ABCDEFG new location in a different DNA sequence ABEFG ABCDCDEFG
Determine effect of mutation during translation 1. Determine amino acid chain made by original mRNA strand 2. Determine amino acid chain made by mutant mRNA strand 3. Compare the two chains a. No changes = silent mutation b. One amino acid changed = missense mutation c. Amino acid chain ends sooner = nonsense mutation d. Multiple amino acids changed = frameshift mutation
Mutation in traits can be organized by their effect • Neutral mutations – no effect on survival (eye color) • Harmful mutations – decrease survival (cancer) • Beneficial mutations – increase survival (disease resistance)
Biology 6E Biology 6F - Genetics and Punnett Squares
Vocabulary character - a recognizable feature controlled by genetics (ex: fur color) trait - a version of a character (ex: white fur) allele - the section of DNA that codes for a specific trait genotype - an organism’s genetic makeup for a character (ex: Ww) phenotype - an organism’s appearance for a character (ex: white fur) homozygous - having two of the same alleles for a character (ex: WW) heterozygous - having two different alleles for a character (ex: Ww)
Types of dominance • complete dominance - heterozygous individuals display dominant trait • incomplete dominance - heterozygous individuals display an intermediate between traits • codominance - heterzygous individuals display both traits at once
Punnett Squares
GR Gr gR gr G g G GGRR GGRr GgRR GgRr R G GG Gg Organize outcomes from genetic crosses G GGRr GGrr GgRr Ggrr r
g Gg gg Each box represents an g GgRR GgRr ggRR ggRr equally likely outcome R g GgRr Ggrr ggRr ggrr r
You can use the five steps below to solve any genetics problem
Biology 6F Meiosis & Sexual Reproduction
Meiosis – type of cell division in which daughter cells receive only half the number of chromosomes present in parent cell • Produces gametes – specialized sex cells
Homologous chromosomes – chromosomes that control the same hereditary traits, similar in size and shape • Synapsis – pairing of homologous chromosomes) o Crossing over – event during synapsis in which material is exchanged, mixing genes. • Independent assortment – homologous chromosomes have equal chance of going to either gamete
Sexual reproduction – reproduction in which a new individual (zygote) is produced by the union (fertilization) of the nuclei of two gametes • Significance of meiosis o Produces gametes needed o Increases genetic variation through independent assortment and crossing-over
Biology 6G DNA Technology
Chromosomal analysis – procedure used to determine chromosomal abnormalities • Karyotype – photograph of arranged chromosomes from a cell • Patient karyotype compared to normal karyotype to determine presence of genetic diseases
DNA fingerprinting – technique that creates a pattern of DNA fragments • Used to identify individual organisms or compare individuals • Procedure 1. Samples taken from individuals 2. DNA separated from cells, cut by restriction enzymes 3. Cut DNA run through gel electrophoreses, separates by size 4. Samples compared
Genetic engineering – direct manipulation of genes Cloning – process used to make multiple copies of a desired gene, • Used for gene therapy, pharmaceutical drug production, increasing agricultural productivity • Procedure 1. DNA containing gene is isolated from organism 2. Gene copies are inserted into plasmids 3. Recombinant DNA is inserted into bacteria cells 4. Bacteria cells reproduce, each contain desired gene Gene mapping – technique used to determine the location of a gene • Used to identify the location of a gene and for genetic screening • Procedure 1. Radioactive or fluorescent DNA probe created to match sequence of desired gene 2. Organism’s DNA is unwound 3. DNA probe base-pairs with complementary sequence
Biology 6H Common Ancestry
Common ancestry – scientific theory that groups of related organisms share a common ancestor
Fossils – preserved traces of remains of living organisms from the past Evidence for common ancestry • When fossils are arranged chronologically, can see a progressive change in organisms from shared ancestor • Generally less diversity further in record, indicating shared ancestors Limitations • Significant gaps in fossil records because of low fossilization rates • Limited conclusions (no function or behavior)
Anatomical homologies – similar structures between different organisms Evidence for common ancestry • Homologous structures – similar structures that share an ancestral form (ex: forearms in vertebrates) • Vestigial structures – degenerated and/or nonfunctional structures Limitations • Must differentiate between homologous and analogous structures
Biology 7A Common Ancestry
Molecular homologies – similar stretches of genetic material and/or proteins between different organisms Evidence for common ancestry • Universal genetic code (same bases, same codon table) • Similar genomes between related species • Conserved vital proteins (ribosomes) Limitations • Mutation rates difficult to accurately analyze • Gene regulation hard to study
Developmental homologies – similar features in embryos of different species Evidence for common ancestry • Ancestral forms during development (teeth in baleen whales) • Similar hox genes (code for development) Limitations • Gene regulation hard to study
Biogeography – the study of the distribution of species, organisms, and ecosystems through geological time Evidence for common ancestry • Similar organisms found in similar environments across the world • Splintered populations on islands Limitations • Depends on other methods to verify hypotheses
Biology 7A The Fossil Record
Fossils – preserved traces or remains of living organisms • Require specific conditions to form
How can groups suddenly appear in the fossil record? • Some organisms don’t fossilize well • Species may evolve into form that is more favorable for fossilization o Organisms may appear suddenly when new form is reached • Gap in record may exist between two forms
Why does stasis appear in the fossil record? • Stasis – a period in which species exhibits limited morphological change • If no trait is being selected for, no natural selection occurs, no change will occur (stasis) o Ex: crocodile, horseshoe crab
Why do groups seem to appear and change sequentially in the fossil record? • Slow response to constant natural selection pressure o Ex: coiled oysters became larger, thinner, flatter to be more stable in disruptive water
Biology 7B Natural Selection in Populations
Natural selection – process whereby organisms with favorable variations survive and produce more offspring than less well-adapted organisms • Individuals with most adaptive variations survive and pass on traits • Over time, population shifts to have more offspring with trait
Genetic Equilibrium – the genetic makeup of a population will remain relatively stable unless something happens to make it change • Populations in genetic equilibrium do not change or evolve • For evolution to take place something must upset the genetic equilibrium of a population • Natural selection upsets genetic equilibrium and causes changes in populations
Example: Natural selection in giraffe population • Giraffe population had short necks and ate grass • Some had longer necks than others – Could eat lower leaves of trees when grass was scarce – More likely to survive – Offspring would inherit favorable variation of a longer neck • Over generations, average neck length in population increases • No individual evolved to have a longer neck during its lifetime, the population slowly evolved to having a longer neck on average
Mutations occur in individuals Mutations enable natural selection to occur Natural selection is a process that affects a population Individuals do not evolve
Biology 7C Differential Reproductive Success
Differential reproductive success – phenomenon in which one group has more offspring than another • Caused by natural selection acting on variations within a population o Organisms with favorable variations have a higher chance of living and producing offspring with these variations
Biotic potential – the highest rate of reproduction possible for a population under idea conditions
Carrying capacity – the number of individuals of a given population that the environment can support • Caused by limited food, fresh water, and space • Limits create competition, winners survive and reproduce
Example: giraffe evolution via differential reproductive rates • Giraffe population had short necks and ate grass o Variation: some had longer necks o Population: large herds o Limitation: food sources • Longer-necked giraffes had a higher reproductive rate • Over time, population evolved longer necks
Biology 7D Natural Selection, Adaptation, & Diversity
Adaptation – trait that helps an organism survive and/or reproduce in its unique environment • Natural selection favors variations of traits that increase organism’s ability to survive and reproduce Natural selection can increase or decrease variation within a species Directional selection – a single variation of a trait that was not previously favored is now favored in a species, usually a result of migration or environmental changes • May increase or decrease diversity within a species Diversifying selection – multiple variations of a trait are favored in a single species • Increases diversity within a species, might lead to separate species Stabilizing selection – a single variation of a trait is favored in a species • Decreases diversity within a species
Natural selection can increase or decrease variation among species • If different traits are favored in different species, diversity increases o Different food sources for birds, different beaks across species • If similar traits are favored in different species, diversity decreases o Same need to retain water in plants, same leaves across species
Biology 7E Evolutionary Mechanisms
Gene pool – all of the genes in a population • Allelic frequency – the frequency of a specific allele • Evolution – change in frequencies of alleles in a population over time
Genetic drift – changes in allele frequencies because of random events • Generally affects smaller populations because of probability Effects on gene pools • Frequency of each allele changes • Rare mutations can become lost or more common
Gene flow – preserved traces of remains of living organisms from the past • Caused by migration or seed transfer Effects on gene pools • New allele added to gene pool
Biology 7F Evolutionary Mechanisms
Mutation – a change in the nucleotide sequence of DNA • Frame shift mutation – codon divisions are moved, changing the rest of the DNA sequence - Insertion – a nucleotide is added to the sequence - Deletion – a nucleotide is removed from the sequence • Substitution – a different nucleotide is used, only affect the codon they occur within Effects on gene pools • New allele could be added
Recombination – exchange of DNA between two chromosomes Effects on gene pools • Alleles moved, but no net change on gene pool
Biology 7F Cell Complexity
Prokaryote – “before nucleus,” simple cell lacking nucleus (bacteria) Eukaryote – “true nucleus,” more complex cell containing nucleus (plant)
What life began first? Theory: prokaryotes appeared first • Evidence: microfossil record o First: simple, single-celled cells without internal structures (prokaryotes) o Later: cells containing internal structures (eukaryotes)
How did the first prokaryotes evolve? Theory: bubble-like cell membranes formed naturally (bubble theory) • Evidence: coacervates o Bubble-like structures that naturally form hollow spheres
How did complex eukaryotes evolve? Theory: prokaryotes evolved into eukaryotes • Evidence: bacteria structure o Bacterial inward foldings similar to nucleus and endoplasmic reticulum Theory: prokaryotes became some organelles (endosymbiosis) • Evidence: nature of some organelles o Endosymbiotic bacteria exist currently o Mitochondria, chloroplasts, and centrioles contain their own DNA similar in size and character to bacterial DNA
Biology 7G Taxonomy
Taxonomy – the branch of biology that classifies and names living things • Uses characteristics of organisms and a universal system – Every organism has a specific name – Organisms are assigned to levels of classification
Common name – name given to an organism by the people in an area • An organism can have many common names leading to confusion • Examples: mountain lion, puma, cougar
Carolus Linnaeus – developed a standardized taxonomic system • Two-word (binomial) naming system • Organisms with similar structures placed in same taxonomic group
Scientific name – standard binomial name accepted by all scientists • Uses genus and specific name to create name of species Species Genus Specific name Felis concolor
Importance of taxonomy • Needed to orderly classify vast diversity of organisms • Allows for universal understanding • Ability for similarities to be compared • Show common ancestry
Biology 8A Taxonomy
Every organism is classified at each nested level. If two organisms share a class, they are in the same phylum and kingdom, but they might be in different lower levels.
Kingdom
Phylum
Class
Order
Family
Genus
Species
Biology 8A Classifying Organisms
Seven levels of taxonomy • Kingdom More broard • Phylum • Class More organisms • Order • Family More speci ic • Genus Less organisms • Species
The more levels two organisms share, the closer they are related.
Identifying where an organisms belongs using shared characteristics 1. For each characteristic given, determine which possible groups are eliminated a. Ex: If the organism is multicellular, it cannot be in kingdom Bacteria or Archaea 2. Once all characteristics are analyzed, there should only be one possible group left
Cladogram – branching diagram showing evolutionary descent • Each split represents appearance of new trait(s) • Related organisms are closer together
Dichotomous key – tool used to identify organisms Identifying where an organisms belongs using a dichotomous key 1. Start at number one 2. For each number, choose the trait most applicable to the organism 3. End when trait chosen provides name of group or species
Biology 8B Taxonomic Groups
Group Major Characteristics Examples (Kingdom) Archaea Prokaryotes, cell wall, may live in extreme Methane-producing archaea, environments, unicellular, autotrophs or heterotrophs thermophiles
Bacteria Prokaryotes, cell wall made of peptidoglycan, E. coli, salmonella unicellular, autotrophs or heterotrophs
Protista Eukaryotes, unicellular or multicellular, autotrophs or Algae, paramecia, euglena, diatoms heterotrophs, some have cell wall, many are microscopic Fungi Eukaryotes, most are multicellular, cell walls, absorbs Mushrooms, molds, yeasts nutrients through cell wall, sessile
Plantae Eukaryotes, most are multicellular, cell walls Ferns, mosses, conifers, flowering composed of cellulose, photosynthetic, autotrophs plants
Animalia Eukaryotes, multicellular, heterotrophs, most are Mammals, birds, insects, worms, motile sponges
Biology 8C Biomolecules
Carbohydrates – sugars and starches, made of C, H, and O • Monosaccharide – subunit of carbohydrates (glucose, fructose, and galactose) • Disaccharide – molecule formed by joining two monosaccharides via dehydration synthesis (maltose, sucrose, and lactose) • Polysaccharide – long chain of repeating sugar units (starch, glycogen, cellulose, and chitin) Structure & Function • Multiple C-H bonds: release net energy when broken (starch and glycogen) • Strong structure: forms tough, structural parts in plants, arthropods, and fungi
Lipids – fats, oils, and steroids, non-polar and hydrophobic (insoluble in water), primarily made of C, H, and O. • No universal subunit • Glycerides (fates and oils) – combination of fatty acids and glycerol o Saturated – carbon atoms have maximum number of hydrogen atoms, pack tightly, fats o Unsaturated – contain one or more carbon-carbon double bonds, back loosely, oils • Steroids – backbone has four fused carbon ring o Anabolic steroids – increase protein synthesis o Cholesterol – maintain cell membrane shape and fluidity, cell signals, precursors to other molecules Structure & Function • Multiple C-H bonds: release net energy when broken (fats and oils) • Not water soluble: component of cell membranes • Act as chemical messengers
Biology 9A Biomolecules
Proteins – sugars and starches, made of C, H, N, and O • Amino acids – subunit of proteins, central carbon with amino group, hydrogen, carboxylic acid, and r group (unique to amino acid). • Dipeptide – two amino acids joined via dehydration synthesis, peptide bond • Polypeptide – multiple amino acids joined together, folds into protein Structure & Function • Modular nature allows for diversity o 20 different amino acids (different R groups) o Different amino acid sequence changes protein produced • Fibrous proteins – fiber-like, structural • Globular proteins – compact and spherical, act as hormones, antibodies, enzymes, and transport proteins
Nucleic acids – DNA and RNA, made of C, O, H, N, P • Nucleotide – subunit of nucleic acids, phosphate group, 5-carbon sugar, and nitrogenous base (A, G, C, T, or U) • DNA – stores genetic code, contains deoxyribose sugar, double- stranded (A pairs with T, G pairs with C) • RNA – carries genetic code to cytoplasm, acts as enzymes Structure & Function • Complementary bonding allows for replication o New cells inherit genetic material from parent cells • Sequence of bases stores information o DNA is the blueprint of genetic information
Biology 9A Biomolecules
Biomolecule Subunit Function Example Proteins Globular Amino acids Catalysis; Enzymes; transport Hemoglobin Fibrous Amino acids Support Collagen, elastin
Nucleic Acids DNA Nucleotides Genetic code Chromosomes
RNA Nucleotides Protein Messenger RNA synthesis Ribosomal RNA Enzymes Lipids Glycerides Glycerols and Energy storage Butter, corn oil fatty acids Steroids Carbon rings Messengers, Cell membrane fluidity Carbohydrates Starch Monosaccharaides Energy storage Potatoes in plants Glycogen Monosaccharaides Energy storage Liver product in animals Cellulose Monosaccharaides Structural Paper, celery support strings
Biology 9A Photosynthesis & Respiration
Photosynthesis – process by which some autotrophs capture energy from the environment
6CO2 + 6H2O + energy C6H12O6 + 6O2
carbon water sunlight sugar oxygen dioxide (glucose)
Cellular Respiration – process by which some living things convert stored energy into usable energy and heat
C6H12O6 + 6O2 6CO2 + 6H2O + energy
sugar oxygen carbon water ATP (glucose) dioxide heat
Photosynthesis & Cellular Respiration Matter is recycled within ecosystems (through trophic levels) Energy flows through ecosystems (in from the sun, out as heat and work)
Biology 9B Enzymes
Enzyme – protein or RNA molecule that acts as a biological catalyst Substrate – substance than an enzyme acts upon Product – substance that is created
Characteristics of Enzymes • Names usually end in suffix –ase • Bind to specific substrate(s) • Not consumed during the reaction • Enable cell reactions to proceed at biological temperatures o Lower the amount of activation energy required for reaction
Two binding theories • Lock-and-key model – substrate molecule fits closely into enzyme (just like a key in a lock) • Induced fit model – enzyme’s shape changes slightly to bind with substrate, more widely accepted
Process • Substrate molecule fits into active site on enzyme o “Enzyme-substrate complex” • Enzyme shape changes slightly to bind to substrate o “Induced fit” • Enzyme catalyzes a chemical reaction in the substrate o Involves breaking or forming chemical bonds • Products are released • Enzyme is ready to bind to another substrate
E + S ES E + P
Biology 9C Formation of Organic Molecules
Where did molecules originate? • Primordial seas (most widely accepted) o Reducing atmosphere – many hydrogen atoms and electrons, no oxygen • Surface of primordial clay o Result of chemical reactions on silicate surface o Clay might have acted as lattice to join monomers into polymers • Deep sea vents o Synthesized from metal sulfides in vents
How did the molecules originate? • Primordial seas (most widely accepted) o Miller-Urey experiment reproduced conditions and found simple organic molecules, including amino acids o Disagreement: composition of early atmosphere • RNA world o RNA formed first, then allowed creation of proteins o Ribozymes – RNA molecules that catalyze their own assembly o Disagreement: RNA too unstable and complex to form spontaneously • Bubble theory o Bubble-like structures formed hollow bilayer spheres of water because of chemical properties (resemble cell membranes) o Disagreement: “protocells” have never been created in lab o Disagreement: atmosphere could not have supported enzyme activity needed
Biology 9D Interactions Among Animal Systems
Regulation Regulation – process of maintaining vital body conditions within an acceptable range in order to preserve homeostasis • Homeostasis – stable internal conditions required for body systems to function • Negative feedback – mechanism in which when a change is detected, the body reacts until the body is returned to a normal range
Regulatory examples: Body temperature: integumentary, nervous, and muscular • Skin (integumentary) and brain (nervous) monitor temperature • If too high, brain signals skin’s sweat glands to cool body • If too low, brain signals muscles (muscular) to contract
Heart and respiration rates: circulatory, respiratory, and nervous • Receptors (nervous) monitor blood pressure and oxygen levels • If too high, heart (circulatory) or lungs (respiratory) decrease rate • If too low, heart (circulatory) or lungs (respiratory) increase rate
Blood concentrations: endocrine, nervous, excretory, integumentary, digestive, and circulatory • Brain (nervous) signals endocrine glands (endocrine) to produce hormones, which travel through blood (circulatory) • Kidneys (excretory) signaled to release more or less water as needed • Skin (integumentary) can sweat to lower water levels • Liver (digestive) releases glucose and insulin to change sugar levels
Biology 10A Interactions Among Animal Systems
Nutrient absorption: digestive, muscular, and circulator • Mouth (muscular and digestive) chews food, sent through throat (muscular and digestive) to stomach • Food churned (muscular) and chemically digested (digestive) • Blood vessels (circulatory) absorb nutrients through microvilli in intestine (digestive)
Reproduction: reproductive, endocrine, and circulatory • Hormones (endocrine) created, travel through blood (circulatory) to stimulate and regulate organs (reproductive) • Organs (reproductive) create and/or release gametes, allow for fertilization to occur • In mammals, blood (circulatory) delivers nutrients to developing fetus
Defense against injury: integumentary, skeletal, muscular, and nervous • Skin (integumentary) and skeleton (skeletal) protect organs from environment • Receptors in skin (integumentary) detect changes and danger, spinal column (nervous) send signals for muscles (muscular) to move away
Defense against illness: integumentary, respiration, digestive, circulatory, and immune • Skin (integumentary) and mucus and hairs along passageways (respiratory) act as physical barrier to pathogens • Stomach acids (digestive) kill pathogens in food • Specialized phagocytes and lymphocytes (immune) travel through blood (circulatory) and attack pathogens
Biology 10A Interactions Among Plant Systems
Plants are divided into two organ systems: • Shoot system – above-ground (leaves, flowers) • Root system – below-ground (roots)
Each organ within these systems has three types of tissue • Dermal – barrier • Ground – metabolic functions • Vascular - transport
These tissues interact to carry out transport, reproduction, and response
Reproduction • Asexual o Shoot or root systems produce new plant • Sexual o Shoot system produces flowers o Shoot and root systems produce hormones to control process
Biology 10B Interactions Among Plant Systems
Transport • Food o Produced in ground tissue of the shoot system o Transported by phloem throughout plant • Water & minerals o Absorbed in tissues of the root system o Transported by xylem throughout plant • Hormones o Produced in ground tissue of both systems o Transported by phloem and xylem
Response • Hormones produces and transported in both systems allow plants to respond to light and gravity o Shoot system grows toward light (phototropism) o Shoot system grows away from gravity (negative gravitropism) o Root system grows toward gravity (positive gravitropism)
Biology 10B Levels of Organization
Ecologists use nested levels of organization to make interactions clear
Level Definition Example Atom smallest representative unit of an hydrogen atom element Molecule two or more atoms bonded together DNA molecule
Cell smallest unit capable of life epithelial cell made of multiple molecules Tissue similar cells working together epithelial layer
Organ different tissues working together stomach
Organ System different organs working together digestive system
Organism an individual life form flamingo composed of at least one cell Population multiple organisms of one species flock of living in one area flamingos Community different populations living in one flamingos, reeds, area and spoonbills Ecosystem all of the populations in one area and a Florida wetland their environment Biome similar ecosystems found on Earth wetlands
Biosphere all of the ecosystems on Earth majority of Earth
Biology 10C Levels of Organization
These levels of organization are nested within each other. Each level contains the matter below it.
Biosphere
Biome
Ecosystem
Community
Population
Organism
Organ system
Organ
Tissue
Cell
Molecule
Atom
Biology 10C Homeostasis
Homeostasis – maintaining a stable, internal environment • Involves body systems working together, monitoring levels of variables, and correcting changes
Negative feedback mechanism – control system that monitors and corrects changes to maintain homeostasis • Regulation occurs in reverse direction as perturbing factor • Returns body to homeostasis • Ex: when body warms up, systems work to cool body down
Positive feedback mechanism – control system used by body to push a change further in the same direction • Regulation occurs in same direction as perturbing factor • Causes body to leave homeostasis • Ex: pressure during childbirth stimulate contractions, creating more pressure, creating more contractions
Biology 11A Response to External Factors
These three levels respond to external factors • Organism – an individual life form • Population – all the individuals of a given species in a particular area • Community – all the different populations of organisms in an area
Populations are limited in size • Biotic potential – the highest rate of reproduction possible for a population under ideal conditions • Carrying capacity – number of individuals of a given population that the environment can support • Limiting factors - factors or conditions which affect the growth rate and size of populations and communities
Density-independent factors – environmental conditions that affect a population regardless of its density • Ex: Natural disasters o Organism: injured or killed o Population: size decreases from individuals killed o Community: affected as populations shrink Density-dependent factors – factors that affect population growth as a result of density • Ex: Predation o Organism: killed (prey) or fed (predator) o Population: rises or falls depending on other population o Community: when there are too many predators, prey population shrinks causing predator population to shrink
Human growth occurs at an exponential rate because of medical advancements, agricultural technology, and improved sanitation
Biology 11B Microorganisms
Microorganisms – living things that cannot be seen with the naked eye • Generally single-celled but can form cell clusters • All prokaryotes (bacteria) and some eukaryotes (fungi and protists)
Maintain Health of Organisms • Help digestion by breaking down compounds • Used in biotechnology for vaccines, antibiotics, genetic engineering
Maintain Health of Ecosystems • Recycle carbon for plants to use • Recycle nitrogen for plants to use • Create sugars in marine ecosystems
Disrupt Health of Organisms • Cause disease like malaria and ringworm
Disrupt Health of Ecosystems • When numerous, toxins become concentrated
Images by USGOV [Public Domain] Biology 11C Ecological Succession
Succession – orderly change in makeup of a community over time • Primary succession – occurs in a newly formed area • Secondary succession – occurs in an area that has been disturbed • Pioneer community – first inhabitants in a new community, changing o Harsh environment, biomass increasing, energy consumption and nutrient cycling inefficient, low species diversity • Climax community – established community, little change o Favorable environment, biomass stable, energy consumption and nutrient cycling efficient, high species diversity
Species, populations, and communities change over time • Unfavorable environment Favorable environment • Few food sources Many food sources • Few species Many species Diverse populations • Pioneer community Climax community
Example: a new pond is formed (primary succession) 1. No organisms 2. Algae and bacteria invade 3. Heterotrophic protists and small invertebrates arrive 4. Floating plants (pondweed) grow 5. Larger plants (cattails) grow around edges 6. Larger animals arrive 7. Might become marsh and fill in 8. Shrubs and trees can grow
Biology 11D Biology 12A - Ecological Relationships
Ecological Relationships
Predatation - one organism hunts and kills another for nutrition
Commensalism - one organism benefits and the other is not affected
Parasitism - one organism benefits and the other is harmed
Mutualism - both organisms benefit
Competition - both organisms are harmed
You can use the four steps below to determine the relationship
Clues for determining faces
benefits not affected harmed killed nutrition unaffected not fatal dies eats not hurt loses prey gains not helped host fatal Biology 12A Adaptations
Variation – a difference that exists among individuals of a group of organisms
Adaptation – any variation in an organism that makes it better suited to its environment, usually fulfills a survival requirement
Animal Survival Requirements Plant Survival Requirements Habitat Habitat Food and water Water and nutrients Protection from predators Sunlight Protection from consumers
Different ecosystems require different adaptations Examples: • Tundra: freezing cold, soil frozen o Plants: short to avoid wind o Animals: migrate to avoid coldest periods • Desert: very little water, can be very hot o Plants: long roots to find water o Animals: large ears to radiate heat • Marine coasts: dry out during day, harsh waves o Plants on coast: holdfasts to stay on rocks o Animals on coast: close tightly to hold in water • Marine deep: no light o Animals: glow to attract prey
When comparing adaptations of organisms: • Consider the challenges in their environment • How do they combat these challenges? o These may be adaptations
Biology 12B Energy Flow Through Trophic Levels
General Trophic Levels Term Level Definition Type Example Producer 1 Organism which produces Autotroph Grass its own food
Primary 2 Organism which primarily Heterotroph, Grasshopper consumer eats producer(s) herbivore
Secondary 3 Organism which primarily Heterotroph, Lizard consumer eats primary consumer(s) carnivore or omnivore Tertiary 4 Organism which primarily Heterotroph, Snake Consumer eats secondary consumer(s) carnivore or omnivore Decomposer N/A Organism which breaks Heterotroph Fungi down dead matter and returns nutrients to soil
Matter cycles through ecosystems (returned by decomposers) Energy flows through ecosystems (enters from sun, lost as heat) • Food chain – sequence of organisms feeding on a lower trophic level • Food web – network of interacting food chains in an ecosystem
Ecological pyramids visualize food chains • Pyramid of energy – amount of energy in organisms o Organisms use 90% of energy obtained for metabolism o Only 10% of energy obtained is passed onto next level • Pyramid of numbers – number of organisms • Pyramid of biomass – total mass of dry, organic matter • In all pyramids, amounts typically decrease as trophic levels increase because of energy loss
Biology 12C Limiting Resources
Environmental factors – components of the environment that affect a species survival • Biotic factors – living components of an environment o Example: food • Abiotic factors – non-living components of an environment o Example: water • Density-dependent factors – effects vary based on density o Example: disease travels better in a dense population • Density-independent factors – affects all populations equally o Example: drought hurts all populations
Limiting resources – environmental factors that are needed by a species, but exist in limited quantities • Create competition • Food (biotic), affected by changes in prey population, seasonal weather cycles, natural disasters, and human activity • Water (abiotic), affected by seasonal weather cycles, natural disasters, and human activities • Space (abiotic), affected by natural disasters and human activities
Biology 12D Matter Cycles
Carbon – key element in organic matter, in all biomolecules Carbon cycle – means by which carbon is cycled between the environment (carbon dioxide) and living tissues (biomolecules)
Disruptions to the cycle • Burning of fossil fuels – release excess carbon dioxide • Deforestation – release excess carbon dioxide, decrease in photosynthesis • Additional humans and animals – release excess carbon dioxide
Biology 12E Matter Cycles
Nitrogen – essential element for life, in all proteins Nitrogen cycle – means by which nitrogen gas converted to usable form then cycled through ecosystem
Disruptions to the cycle • Burning of fossil fuels – release excess nitrogen into atmosphere • Excessive irrigation and erosion – washes away nitrogen from soil • Fertilizing crops – excess nitrogen, algal blooms • Ranching – waste releases excess nitrogen, poor water quality and plant growth
Biology 12E Environmental Change
Ecosystem – physically distinct, self-supporting unit of interacting organisms and their surrounding environment
Conditions for stable ecosystem • Source of energy • Producers using energy sources to synthesize organic compounds • Materials cycling between organisms and environment
When analyzing how an event will change an ecosystem, keep these questions in mind 1. Are producers affected? 2. Did nutrient/mineral levels change? 3. Are any organisms directly hurt/killed? 4. Did habitat loss occur?
Example: Oil Spill 1. Are producers affected? Yes, toxic oil can kill producers. 2. Did nutrient/mineral levels change? No, they are not affected. 3. Are any organisms directly hurt/killed? Yes, oil is toxic to all life. 4. Did habitat loss occur? Yes, areas of ocean and shore contaminated with toxic oil.
Biology 12F