Biology

Organelles

literally meaning, "little organs", organelles are structures that act as specialized organs within a cell. Understanding what each organelle does helps us understand the cell as a whole.

BIG IDEA: Cellular Basis of Life

living things are made of cells. Many living things consist of only a single cell; they are called unicellular organisms. Plants and animals are multicellular. Cells in multicellular organisms display many different sizes, shapes, and functions. The human body contains 200 or more different cell types.

Centrioles

located near the nucleus of the cell, centrioles help organize cell division. Centrioles are not found in plant cells.

Transcription

segments of DNA serve as templates to produce complementary RNA molecules. The base sequences of the transcribed RNA complement the base sequences of the template DNA.

Endoplasmic reticulum (ER)

where lipid components of the cell membrane are assembled, along with proteins and other materials that are exported from the cell.

Transformation

(1) The act, state or process of changing, such as in form or structure; the conversion from one form to another. (2) (biology) Any change in an organism that alters its general character and mode of life; post-natal biological transformation or metamorphosis. (3) (genetics) The genetic alteration of a bacterial cell resulting from the transfer of foreign DNA.

BIG IDEA: Homeostasis

Living things maintain a relatively stable internal environment, a process known as homeostasis. For most organisms, any breakdown of homeostasis may have serious or even fatal consequences.

Translation

The process of decoding an mRNA message into a protein.

Substrates

The reactants of enzyme-catalyzed reactions. The substrates bind to a site on the enzyme called the active site. The active site and the substrates have complementary shapes.

Molecule

The structure that results when atoms are joined together by covalent bonds. The molecule is the smallest unit of most compounds.

Solution

ions dispersed in liquid-- a type of mixture.

Adhesion

an attraction between molecules of different substances.

Cohesion

an attraction between molecules of the same substance.

Golgi apparatus

an organelle which appears as a stack of flattened membranes. The Golgi apparatus modifies, sorts, an packages proteins and other materials from the endoplasmic reticulum for storage in the cell or release outside the cell.

Ribosomes

are small particles of RNA and protein found throughout the cytoplasm in all cells. Ribosomes produce proteins by following coded instructions that come from DNA.

Definition of a Living thing

Living things are made up of basic units called cells, are based on a universal genetic code, obtain and use materials and energy, grow and develop, reproduce, respond to their environment, maintain a stable internal environment, and change over time.

Point Mutations: Substitutions

in a substitution, one base is changed to a different base. Substitutions usaully affect no more than a single amino acid, and sometimes have no affect at all.

Cell Theory

1. All living things are made up of cells. 2. Cells are the basic units of structure and function in living things. 3. New cells are produced from existing cells.

Biosphere

A connection with which organisms are linked to one another and to the land, water, and air around them. Relationships between organisms and their environments depend on the cycling of matter and the flow of energy.

Base Pairing

A near perfect fit in DNA strands that occurs between A-T and G-C. This is the reason for Chargaff's rule

Replication

A process in which a cell duplicates it's DNA. This process, which occurs during late interphase of the cell cycle, ensures that each resulting cell has the same complete set of DNA molecules. During replication, the DNA molecule separates into two strands and them produces two new complementary strands following the rules of base pairing. Each strand of the double helix DNA serves as a template, or model, for the new strand.

Asexual Reproduction

A single organism produces offspring identical to itself.

Theory

A well-tested explanation that unifies a broad range of observations and hypotheses and that enables scientists to make accurate predictions about new situations.

BIG IDEA: Interdependence in Nature

All forms of life on Earth are connected into a biosphere, which literally means "living planet." Within the biosphere, organisms are linked to one another and to the land, water, and air around them. Relationships between organisms and their environments depend on the cycling of matter and the flow of energy. Human life and the economies of human societies also require matter and energy, so human life depends directly on nature.

BIG IDEA: Growth, Development, and Reproduction

All living things reproduce. Newly produced individuals are virtually always smaller than adults, so they grow and develop as they mature. During growth and development, generalized cells typically become more and more different and specialized for particular functions. Specialized cells build tissues, such as brains, muscles, and digestive organs, that serve various functions.

BIG IDEA: Unity and Diversity of Life

Although life takes an almost unbelievable variety of forms, all living things are fundamen- tally similar at the molecular level. All organisms are composed of a common set of carbon-based molecules, store information in a com- mon genetic code, and use proteins to build their structures and carry out their functions. One great contribution of evolutionary theory is that it explains both this unity of life and its diversity.

Polymer

Coming from the Greek "many parts", polymers are large chains of connected monomers.

Monomer

Coming from the Greek for "single part", monomers are smaller units that join together to create polymers. Monomers may be identical or different.

Carbohydrates

Compounds made up of carbon, hydrogen, and oxygen atoms, usually in a ratio of 1:2:1. Living things use carbohydrates for their main source of energy.

DNA Polymerase

DNA polymerase is an enzyme that joins individual nucleotides to produce a new strand of DNA. Besides producing the sugar-phosphate bonds that join nucleotides together, DNA polymerase also "proofreads" each new DNA strand, so that each molecule is a near-perfect copy of the origional.

BIG IDEA: Structure and Function

Each major group of organ- isms has evolved its own particular body part "tool kit,"—a collection of structures that have evolved in ways that make particular functions possible. From capturing food to digesting it, and from reproducing to breathing, organisms use structures that have evolved into different forms as species have adapted to life in different environments. The structures of wings, for example, enable birds and insects to fly. The structures of legs enable horses to gallop and kangaroos to hop.

Codon

Each three-letter "word" of the Genetic code in mRNA. A Condon is a group of three nucleotide bases in messenger RNA that specifies a particular amino acid to be added to the poly peptide chain.

Macromolecules

Giant molecules made from hundreds or even thousands of smaller molecules.

Saturated

If each carbon atom in a lipid's fatty acid chains is joined to another carbon atom by a single bond, the lipid is said to be saturated. The fatty acids contain the maximum possible number of hydrogen atoms.

Point Mutations: Insertions and Deletions/ FRAMESHIFT MUTATIONS

Insertions and deletions are point mutations in which one base is inserted or removed from the DNA sequence. The effects of these changed can be dramatic.They are also called FRAME SHIFT MUTATIONS because they "shift" the reading frame and can change every amino acid that follows the point of the mutation.

BIG IDEA: Information and Heredity

Living things are based on a universal genetic code. The information coded in DNA forms an unbroken chain that stretches back roughly 3.4 billion years. Yet the DNA inside your cells right now can influence your future-- your risk of getting cancer, the amount of cholesterol in your blood, and the color of your children's hair.

BIG IDEA: Matter and Energy

Living things obtain and use material and energy. Life requires matter that serves as nutrients to build body structures, energy that fuels life's processes. SOme organisms, such as plants, obtain energy from sunlight and take up nutrients from air, water, and soil. Other organisms, including most animals, eat plants or other animals to obtain both nutrients and energy. The need for matter and energy link all living things on Earth in a web of interdependent relationships.

Suspensions

Mixtures of liquid (often water) mixed with nondissolved material.

RNA

Ribonucleic acid, like DNA, is a nucleic acid that consists of a long chain of nucleotides. RNA is involved in putting the genetic code into action. first part of the base sequence from DNA is copied into RNA, then RNA uses these instructions to direct the productions of proteins, which help to determine an organisms's characteristics.

BIG IDEA: Science as a Way of Knowing

Science is not a list of facts, but "a way of knowing." The job of science is to use observations, questions, and experiments to explain the natural world in terms of natural forces and events. Successful scientific research reveals rules and patterns that can explain and predict at least some events in nature. Science enables us to take actions that affect events in the world around us. To make certain that scientific knowledge is used for the benefit of society, all of us must understand the nature of science—its strengths, its limitations, and its interactions with our culture.

BIG IDEA: Evolution

Taken as a group, living things evolve. Evolutionary change links all forms of life to a common origin more than 3.5 billion years ago. Evidence of this shared history is found in all aspects of living and fossil organisms, from physical features to structures of proteins to sequences of information in DNA. Evolutionary theory is the central organizing principle of all biological and biomedical sciences.

Dominant theory

The adjective "dominant" means "having the most authority of influence." After an idea has been thoroughly tested, confirmed repeatedly, and is accepted by the majority of scientists, it may become the dominant explanation for a particular phenomenon.

Metabolism

The combination of chemical reactions through which an organism builds up or breaks down materials.

Homeostasis

The condition all organisms need to keep their internal environment relatively stable, even when external conditions change dramatically.

Chargaff's rule

The fact that the percentage of adenine [A] and thymine [T] bases are almost equal in any sample of DNA. The same thing is true for the other two nucleotiedes, guanine [G] and cytosine [C]. So [A]=[T] and [G]=[C].

DNA

The molecule that stores the universal genetic code all organisms need to live, grow, and reproduce.

Polymerization

The process in which large compounds are built by joining smaller ones together.

Biology

The study of life (revolving around several interlocking big ideas: the cellular basis of life; information and heredity; matter and energy; growth, development, and reproduction;homeostasis;evolution; structure and function; unity and diversity of life; interdependence in nature; and science as a way of knowing. Biology includes many overlapping fields that use different tools to study life from the level of molecules to the entire planet.)

Helix

The type of structure (evident in DNA) in which strands of molecules are twisted around each other like the coils of a spring

Disaccharide

a compound made by joining two simple sugars together.

Bacteriophage

a kind of virus that infects bacteria. When a bacteriophage enters a bacterium, it attaches to the surface of the bacterial cell and injects its genetic information into it. The viral genes act to produce many new bacteriophages, which gradually destroy the bacterium. When the cell splits open, hundreds of new viruses burst out.

Nucleus (cell)

a large membrane enclosed structure that contains nearly all the cell's genetic material in the form of DNA and, with it, coded instructions for making proteins and other important molecules. It also controls many of the cell's activities.

Lipids

a large varied group of biological molecules that are generally not soluble in water. Lipids are made mostly from carbon and hydrogen atoms. The common categories of lipids are fats oils and waxes.

Mixture

a material composed of two or more elements or compounds that are physically mixed together but not chemically combined.

Vaculoes

a organelle made of a large membrane-enclosed structure that stores materials like water, salts, proteins, and carbohydrates

Chemical Reaction

a process that changes, or transforms, one set of chemicals into another. Mass and energy are conserves during chemical transformations. They involve changes in the chemical bonds that join atoms in compounds.Chemical reactions that release energy often occur on their own, or spontaneously. Chemical reactions that absorb energy will not occur without a source of energy/

Stimulus

a signal to which an organism responds.

Cell Wall

a strong supporting layer around the cell membrane. The main function of the cell wall is to support, shape, and protect the cell. Cell walls lie outside the cell membrane and most often porous enough to allow water , oxygen, carbon dioxide, and certain other substances to pass through easily.

Catalyst

a substance that speeds up the rate of a chemical reaction. Catalysts work by lowering the reaction's activation energy.

Cell membrane

a thin flexible barrier that surrounds all cells

3 important Differences between RNA and DNA

both's nucleitdes are made up of a 5 carbon sugar, a phosphate group, and a nitrogen base. BUT! 1) the sugar in RNA is ribose instead of deoxyribos. 2) RNA is generally single-stranded and not double stranded. 3) RNA contains uracil in place of thymine.

messenger RNA (mRNA(

carry information from DNA to other parts of the cell.

Sexual Reproduction

cells from TWO parents unite to form the first cell of a new organism.

Prokaryotes

cells that do not enclose DNA in nuclei. Theyy do not separate their genetic material within a nucleus.

Eukaryotes

cells that enclose their DNA in nuclei. In eukaryotic cells, the nucleus separates the genetic material from the rest of the cell.

mutagens

chemical or physical agents in the environment that may cause mutations.

Amino acids

compounds with an amino group (-NH2) on one end and a carboxyl group (-COOH) on the other end Covalent bonds called peptide bonds link amino acids together to form a poly peptide.

Qualitative data

descriptive and other characteristics that cannot usually be counted.

anticodon

each transfer RNA has an anticodon whose bases are complementary to the bases of a codon on the mRNA strand.

Cytosceleton

gives Eukaryotic cells their shape and internal organization by a network of protein filaments. The cytoskeleton helps the cell maintain its shape and is also involved in movement. Microfilaments and microtubles are two of the principle protein filaments that make up the cytoskeleton.

Mutations

heritable changes in genetic information due to a mistake in the copying of DNA

Microtubules

hollow structures made up of proteins known as tublins. In many cells they play critical roles in maintaining cell shape. Microtuble are also important in cell division, where they form a structure known as the mitotic spindle, which helps to separate chromosomes. In some animal cells, organelles called centrioles are also formed in tubulins.Microtubules also help build projections from the surface-- known as cilia (singular: cilium) and flagella (singular:flagellum)-- that enable cells to swim rapidly through liquid.

polypeptides

long chains of amino acids joined together. Polypeptides make up proteins, depending on the amino acids inside them, and the order in which they are joined, the polypeptides create different proteins with different shapes and functions.

Nucleic acids

macromolecules containing hydrogen, oxygen, nitrogen, carbon, and phosphorus. Nucleic acids are polymers assembled from individual monomers known as nucleotides. Nucleic acids store and transmit hereditary, or genetic, information.

Proteins

macromolecules that contain nitrogen as well as carbon, hydrogen, and oxygen. Proteins are polymers of molecules called amino acids. A protein is a functional molecule built from one or more polypeptides.

Nucleotides

monomers used to create Nucleic acids that consist of three parts: a 5-carbon sugar, a phosphate group (-PO4) and a nitrogeneous base.

Point Mutations

mutations that occur at a single point in the DNA sequence. These involve changes in one or a few nucleotides. Point mutations include SUBSTITUSION, INSERTIONS, and DELETIONS. they generally occur during replication

Hydrogen Bond

not as strong as covalent or ionic bonds, and they can form in other compounds as well. An example is the attraction between a hydrogen atom on one water molecule and the oxygen atom on another.

Quantitative data

numbers obtained by counting or measuring.

introns

portions of pre-mRNA molecules that have to be cut out before the RNA can go into action. They are taken out while they are still in the nucleus

ribosomal RNA (rRNA)

proteins are assembled on ribosomes, small organelles composed of two subunits. These subunits are made p of seceral RIBOSOMAL RNA molecules and as many as 80 different proteins.

Enzymes

proteins that act as biological catalysts. Enzymes speed up the chemical reactions that take place in cells.

Prometers

regioms pf DMA that have specific base sequences that RNA can bond to. Prometers are signals in the DNA molecule to show RNA polymerase exactly where to begin making RNA. Similar signals in DNA cause transcription to stop when a new RNA molecule is completed.

RNA polyamerase

similar to DNA polyamerase, RNA polyamerase binds to DNA during transcription and separates DNA strands. It then uses one strand of DNA as a template from which to assemble nucleotides into a complementary strand of RNA. The ability to copy a single DNA sequence into RNA makes it possible for a single gene to produce hundreds or even thousands or RNA molecules

Monosaccharides

single sugar molecules.

Lysosomes

small organelles filled with enzymes. Lysosomes break down lipids,carbohydrates, and proteins into small molecules that can be used by the rest of the cell. They are also involved in breaking down organelles that have outlived their usefulness. They preform the vital function fo removing "junk" that might otherwise accumulate and clutter up the cell

Telomeres

the DNA at the tips of chromosomes.

Cells

the basic units of life

Chloroplasts

the bilogical equivalents of solar power plants, Chloroplasts capture the energy from sunlight and convert it into food that contains chemical energy in a process called photosynthesis.

Nucleus

the center of an atom that is made up of Protons and Neutrons

Polyploidy

the condition in which an organism has extra sets of chromosomes.

Lipid Bilayer

the double-layered sheet that makes up almost all cell membranes. The lipid bilayer gives cell membranes a flexible structure that forms a strong barrier between the cell and its surroundings. The cell membrane regulates what enters and leaves the cell and also protects and supports the cell.

Products

the elements or compounds produced by a chemical reaction.

Reactants

the elements or compounds that enter into a chemical reaction.

Activation Energy

the energy that is needed to get a reaction started.

the genetic code

the language devised from the four letters (A,C,G,U) in RNA. The genetic code is read three "letters" at a time, so that each "word" is three bases long and corresponds to a single amino acid.

Polysaccharides

the large macromolecules formed from monosaccharides.

Atom

the most basic unit of mater. Meaning "unable to be cut" it comes the Greek Philosopher Democritus who asked how many times you could cut an object, while it still remaining the same material.

Cytoplasm

the portion of the cell outside the nucleus. Prokaryotic cells have cytoplasm too, even though they do not have a nucleus.

Mitochondria

the power plants of the cell, Mitochondria convert the chemical energy stored in food into compounds that are more convenient for the cell to use.

Exons

the remaining pieces of pre-mRNA after the introns have been removed. These exons are spliced back together to form the final mRNA

van der Waals forces

the slight attraction that can develop between oppositely charged regions of nearby molecules when molecules are close together. These forces are not as strong as covalent or ionic bonds.

Solvent

the substance in which the solute dissolves.

Solute

the substance that is dissolved.

Gene Expression

the way in which DNA, RNA, and proteins are involved in putting genetic information into action in living cells.

Microfilaments

threadlike structures made up of a protein called actin. They form extensive networks in some cells and produce a tough flexible framework that supports the cell. Microfilaments also help cells move. Microfilament assembly and disassembly are responsible for the cytoplasmic movements that allow amoebas and other cells to crawl along surfaces.

Transfer RNA (tRNA)

transfers each amino acid to the ribosome as it is specified by the coded messages in mRNA.