Carbohydrates

• major source of energy and include sugars and starches made up of carbon, hydrogen, and oxygen

• 2:1 ratio of hydrogen to oxygen

• plants and animals use carbohydrates for maintaining structure within the 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, see example ) and 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, distribute products

Lysosomes – digests 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 membranebound 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 SPECIALIZATION:

cells >>>> tissues >>>> organs >>>> organ systems >>>> organism

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

• as cells mature, they 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 is 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 THEORY:

• the cell is the basic unit of life.

• All organisms are composed of cells

• All cells come from pre-existing 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

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)

C6H12O6 + 6O2  6CO2 + 6H2O + 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)

6CO2 + 6H2O + ENERGY(from sunlight)  C6H12O6 + 6O2 - 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  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  Lactic Acid + 2ATP Alcoholic Fermentation (plant cells)

Glucose  CO2 + Alcohol + 2ATP

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

CELLULAR RESPIRATION

• Food Broken Down

• Energy from Glucose Released

• Carbon Dioxide given off

• Oxygen taken in

• Produces Carbon Dioxide and

• Water Does not require Light

• Occurs in ALL Living Cells Organisms often called Heterotrophs

PHOTOSYNTHESIS

• Food Synthesized

• Energy from Sun stored in Glucose

• Carbon Dioxide taken in

• Oxygen given off

• Produces Sugars (Glucose) from PGAL R

• equires Light

• Occurs only in presence of Chlorophyll Organisms called Autotrophs

CHEMOSYNTHESIS

• Food Synthesized

• Energy from Methane or Inorganic Material (ex: H gas or Hydrogen sulfide)

• Organisms often called chemotrophs

• Organisms called extremophiles

• Live in environments without oxygen

• Anaerobic Bacteria

• Habitats: hydrothermal vents

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

DNA & RNA:

• - Nucleic acids composed of nucleotides

• - Nucleotides composed of:

• Phosphate group

• Sugar

• Nitrogenous base

DNA

• Deoxyribonucleic acid

• Double-stranded,

• twisted helix

• Never leaves the nucleus

• Nitrogenous bases: adenine, thymine, guanine, cytosine (Guanine w/Cytosine, Adenine w/Thymine) (Purines opposite the Pyrimidines) (held together by weak hydrogen bonds)

• Sugar: deoxyribose

• Controls production of all proteins

• DNA Replication: (DNA unravels and each strand makes a new exact copy so that when mitosis takes place, each cell has the exact copy of DNA)

• DNA coiled into chromosomes in nucleus

• Tiny sections of DNA are called genes

• Sequence of bases determines sequence of amino acids in proteins

RNA

• Ribonucleic acid

• Single-stranded

• Leaves the nucleus

• Nitrogenous bases: adenine, uracil, guanine, cytosine (Guanine w/Cytosine, Adenine w/Uracil) Sugar: ribose Three major types of RNA

• (Ribosomal – rRNA; Messenger – mRNA; Transfer – tRNA)

• Leaves the nucleus to carry out functions in cytoplasm

• Transcription: (mRNA is made from one strand of DNA, carries message to ribosomes) Translation: (mRNA translated into a protein at the ribosomes; tRNA transfers amino acids from cytoplasm to ribosomes)

ASEXUAL REPRODUCTION

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

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

MITOSIS

Cell cycle consists of interphase, mitosis, and cytokinesis

Interphase – longest part of cell cycle Growth, metabolism, and preparation for division occurs Duplicates chromosomes (DNA Replication)

Mitosis – division of nucleus of the cell

- Prophase - duplicated chromosomes and spindle fibers appear

- Metaphase – duplicated chromosomes line up randomly in center of cell between spindle fibers - Anaphase – duplicated chromosomes pulled to opposite ends of cell

- Telophase – nuclear membrane forms around chromosomes at each end of cell; spindle fibers disappear; chromosomes disperse

Cytokinesis – division of plasma membrane; two daughter cells result with exact genetic information (in plant cells a “cell plate” forms along the center of the cell and cuts the cell in half; cell plate forms new cell walls once the plasma membrane divides)

RESULTS:

Two daughter cells (body cells)

Same number of chromosomes as original cell (humans = 46)

Cells are diploid (human diploid # = 46 or 23 homologous pairs)

MEIOSIS

Consists of two cell divisions, but only one chromosome replication (sometimes called reduction division)

Each cell division consists of prophase, metaphase, anaphase, and telophase

Occurs only in sex cells – to produce more sex cells (gametes)

First Meiosis Division - Produces cells containing ½ # of double stranded chromosomes

Second Meiosis Division Results in formation of four cells Each cell w/ ½ # of single-stranded chromosomes (haploid cells)

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Sperm

Each primary sperm cell develops into four haploid cells of equal size. As cells mature, the cells lose most of their cytoplasm and develop a long whip-like tail for movement.

Egg

Each primary egg cell develops into one large haploid cell and three smaller haploid cells called polar bodies. The first meiosis division produces one large cell and one polar body. The second meiosis causes the large cell to produce one egg cell and a polar body; the original smaller polar body divides into two polar bodies. The polar bodies eventually disintegrate. The final egg cell is provided with the larger supply of stored nutrients

RESULTS:

Four daughter cells (sex cells)

½ # of chromosomes (haploid) with genetic variation (n = 23)

Sex cells combine during sexual reproduction to produce a diploid individual

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.)

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

Sunlight is the main energy source for living things. Energy flows through an ecosystem from the sun to organisms within the ecosystem in one direction. Two main groups of organisms in the ecosystem are the producers and consumers.

Producers – autotrophs, use sun’s energy to make their own food, plants (grass)

Consumers – heterotrophs, cannot make their own food, eat other living things to get their energy (mice- primary consumers; and hawksecondary consumer)

Species – group of organisms that can interbreed

Population – units of single species

Community – groups of interacting populations

Ecosystem – groups of interacting communities

Habitat – place where an organism lives

Niche – organism’s role within its habitat

SYMBIOTIC RELATIONSHIPS:

Symbiosis – permanent, close association between one or more organisms of different species

Mutualism – a symbiotic relationship in which both species benefit (ex: in subtropical regions, ants protect acacia trees by fighting invaders, acacia tree provides nectar to ants)

Commensalism – symbiotic relationship in which one species benefits and the other species is neither harmed nor benefited (ex: Spanish moss grows on and hangs from limbs of trees, but does not obtain any nutrients from tree, nor harm the tree)

Parasitism – symbiotic relationship in which one organism benefits at the expense of another, usually another species (ex: parasites such as bacteria, roundworms, tapeworms live in the intestines of organisms to obtain nutrients and reproduce, but cause disease in the organisms)

FOOD CHAIN:

- Path of energy from producer to consumer

- Each level is called a trophic level (trophic = energy)

- Approximately 10% energy is transferred to next level

- 90% used for personal metabolism and development

FOOD WEB:

- Interconnected food chains

- Shows all possible feeding relationships at each trophic level in a community

ECOLOGICAL PYRAMID:

- Representation of energy transfer

- Pyramid of Energy – each level represents energy available at that level, 90% decline

- Pyramid of Biomass – each level represents amount level above needs to consume - Pyramid of

- Numbers – each level represents number of organisms consumed by level above it

SPECIES / POPULATION SURVIVAL:

- Natural Selection – mechanism for change in populations; occurs when organisms with favorable variations survive, reproduce, and pass their variations to the next generation; “survival of the fittest”

- Adaptation (Behavioral or Physiological) – evolution of a structure, behavior, or internal process that enables an organism to respond to environmental factors and live to produce offspring

- Limiting Factors (Environmental) – any biotic or abiotic factor that restricts the existence, numbers, reproduction, or distribution of organisms

- Genetic Mutations – any change or random error in a DNA sequence (one gene or many; somatic cells or gametes)

- Biodiversity – variety of life in an area; usually measured as the number of species that live in an area

- Evolution (Macroevolution vs. Microevolution) – gradual change in a species through adaptations over time

- Endangered Species – number of individuals in the species falls so low that extinction is possible

- Extinction – disappearance of a species when the last of its members die

CYCLES: (Matter cannot be created nor destroyed, but can be converted/recycled to other forms)

Water Cycle – water is recycled through evaporation, condensation, precipitation, runoff, groundwater, aquifers, respiration, transpiration, excretion, decomposition

Nitrogen Cycle – producers take in nitrogen compounds in soil and pass to consumers that consume the producers; decomposers (bacteria) break down nitrogen compounds and release nitrogen gas to air or usable nitrogen so the soil

Carbon Cycle – carbon is recycled through respiration, photosynthesis, fuel combustion, decomposition; carbon can be atmospheric or dissolved, or can be found in organic compounds within the body

SUCCESSION:

- orderly, natural changes, and species replacements that take place in communities of an ecosystem over time

Primary Succession – colonization of barren land by pioneer organisms (soil must be developed)

Secondary Succession – sequence of changes that take place after a community is disrupted by natural disasters or human actions (soil already present)