Chapter 1: Science of Biology

Science

an organized way of gathering and analyzing evidence about the natural world

• Way of Observing
• Way of Thinking
• Way of Knowing
• Process not a thing

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Observation

the act of noticing and describing events or processes in a careful, orderly way

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Inference

a logical interpretation based on what scientists already know. Inference + Creative Imagination=Hypothesis

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Hypothesis

a scientific explanation for a set observations that can be tested in ways that support or reject it.

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Controlled Experiment

Testing a scientific hypothesis by designing an experiment that keeps track of various factors that can change, or variables such as temperature, light, time and availability of nutrients.

Only one of the variables should change so researchers can easily tell which variable is responsible for any results observed

All the other variables should be unchanged or controlled

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Variable

various factors that can change,

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Dependent variable

the variable that is observed and that changes in response to the independent variable

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Independent Variable

the variable that is deliberately changed

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Control Group

exposed to the same conditions as the experimental group except for one independent variable.

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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.

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Data

 detailed records of experimental observations

Two Types of Data:

Quantitative Data- numbers obtained by counting or measuring

Qualitative Data- descriptive and involve characteristics that cannot be usually counted

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Bias

a particular preference or point of view that is personal, rather than scientific.

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Biology

the study of life

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DNA

All organisms store the complex information they need to live, grow and reproduce in a genetic code written in a molecule

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Stimulus

a signal to which an organism responds

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Sexual Reproduction

cells from two parents unite to form the first cell of a new organism (which most plants and animals do)

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Asexual Repproduction

 a single organism produces offspring identical to itself

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Homeostasis

the process all organisms need to go through to keep their internal environment relatively stable, even when external conditions change dramatically

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Metabolism

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

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Biosphere

literally means "living planet."  

Within it organisms are linked to one another and to the land, water, and air around them.

Chapter 2: The Chemistry of Life

Atom

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Nucleus

Strong forces  bind protons and neutrons together to form the center of the atom

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Electron

negatively charge particle with only 1/1840 the mass of a proton

Are in constant motion in the space surrounding the nucleus

Are attracted to the positively charged nucleus but remain outside the nucleus because of  the energy of their motion.

Because atoms have equal numbers of electrons and protons the positive and negative  charges balance out, and atoms themselves are neutral

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Element

a pure substance that consists entirely of one type of atom

 More than 100 but only about two dozen are commonly found in living organisms

Are represented by one- or two letter symbols

Ex- C- Carbon, H- Hydrogen, Na- sodium, Hg- mercury

Atomic Number- the number of protons in the nucleus of an element

Ex- Carbon- 6 meaning that each atom of carbon has six protons and six electrons

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Isotopes

atoms of the same element that differ in the number of neutrons they contain

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Compound

is a substance formed by the chemical combination of one or more  element in definite proportions

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Ionic bond

is formed when one or more electrons are transferred form one atom to another

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Ions

positive or negative charged atoms

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Covalent

 electrons are shared  by atoms instead of being transferred.

moving electrons actually travel about the nuclei of both atoms

1. Single Covalent- the atoms share two electrons
2. Double Covalent- the atoms share four electrons
3. Triple Covalent- atoms share six electrons

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Molecule

he smallest unit of most compounds

• The structure that results when atoms re joined together by covalent bonds is called a molecule
• Water molecule- hydrogen two shares with one oxygen- single covalent bond
• When atoms of the same element combine

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Van der Waals forces

intermolecular forces of attraction

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Hydrogen Bond

The attraction between a hydrogen atom with a partial positive charge and another atom with a partial negative charge

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Cohesion

an attraction between molecules of the substance.

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Adhesion

an attraction between molecules of different substances

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Solution

are evenly distributed throughout the solution

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Solute

the substance that is dissolved.

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Solvent

the substance in which the solute dissolves

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Suspensions

 mixtures of water and nondissolved material

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pH scale

a measurement system that indicates the concentration  of H+ ions in solution. The pH scale ranges from 0 to 14. At pH of 7, the concentration of H+ ions and OH- ions is equal

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Acid

any compound that H+ ions in solution. Acidic solutions contain higher of H+ than pure water and have pH values below 7.

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Base

a compound that produced hydroxide (OH_) in solution. Basic, or alkaline, solutions contain lower concentrations of H+ than pure water and have pH values above 7. Strong bases, such as the lye used to in soapmaking , tend to have pH values ranging from 11 to 14

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Buffers

 weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in pH.

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Monomers

Most macromolecules are formed by process known as polymerization, in which large compounds are built by joining smaller ones together.

 The smaller units

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Polymers

monomers join together to form this marcromolecule

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Carbohydrates

compounds made up of carbon, hydrogen, and oxygen atoms, usually in a ration of 1:2:1

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Monosaccharides

Single sugar molecules

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Lipids

a large and varied group of biological molecules that are generally not soluble in water

made mostly from carbon and hydrogen atoms. The common categories of lipids are fats, oils, and waxes.

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Nucleic Acids

macromolecules containing hydrogen, oxygen, nitrogen, carbon and phosphorus

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Nucleotides

polymers assembled from individual monomers, consist of three parts

• 5-carbon sugar
• Phosphate group
• Nitrogenous base

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Proteins

macromolecules that contain nitrogen as well as carbon, hydrogen, and oxygen.

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Amino Acids

are compounds with an amino group on one end and a carboxyl group on the other end.

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Chemical Reaction

 process that changes, or transforms , one set of chemicals into another

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Reactants

the elements or compounds that enter into a chemical reaction

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Products

the elements or compounds produced by a chemical reaction

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Activation Energy

what chemists call the energy that is needed to get a reaction started

 involved in chemical reactions regardless of whether the overall chemical reaction releases or absorbs

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Catalyst

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

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Enzymes

proteins that act as biological catalyst.

Enzymes speed up chemical reactions that take place in cells

Act by lowering activation rates

Very specific, generally catalyzing only one chemical reaction

Part of an enzyme's name is usually derived from the reaction it catalyzes

Ex- Carbonic anhydrase gets it name because it also catalyzed the reverse reaction that removers water form carbonic acid

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Substrates

The reactants of enzymes-catalyzed reactions

Chapter 7

Cells

basic units of life

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Cell Theory

Cell Theory- a fundamental concept of biology

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 form existing cells

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Cell Membrane

a thin flexible barrier in which all cells are surrounded by

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Nucleus

 large membrane, enclosed structure the genetic material in the form of DNA and controls many of the cell's activities

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Eukaryotes

cells that enclose their DNA in a nuclei

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Prokaryotes

cells that do not enclose DNA in nuclei

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Cytoplasm

the portion of the cell outside the nucleus (prokaryotic cells have cytoplasm even they do not have a nucleus)

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Organelles

 many cell structures acting as special organs, literally mean "little organs"

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Vacuoles

 large, saclike, membrane-enclosed structures, store materials like water, salts, proteins and carbohydrates

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lysosomes

 small organelles filled with enzymes, 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

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Cytoskeleton

give the shape and internal organization by these network of protein filaments

Certain parts help transport materials between different parts of the cell

Components may also be involved in moving the entire as in cell flagella and cilia

The cytoskeleton helps the cell maintain its shape and is also involved in movement

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Centrioles

form from tubulins, are located near the nucleus and help organize cell division

Are not found in plant cells

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Ribosomes

Proteins are assembled by ribosomes

are small particles of RNA and protein found throughout the cytoplasm in all cells

Produce proteins by following the coded instructions that come form DNA. Each ribosome turns out proteins in orders from the DNA.

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Endoplasmic Reticulum

(ER)- an internal membrane system where lipid components of the cell membrane are assembled, along with proteins and other materials that are exported from the cell

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Golgi apparatus

appears as a stack of flattened membranes

modifies, sorts and packages proteins and other materials from the endoplasmic reticulum for storage in the cell or release outside the cell

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Chloroplasts

biological equivalents of solar plants (plants and some other organisms have these)

Chloroplasts capture the energy from the sunlight and convert it into food that contains chemical energy in a process called photosynthesis

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Mitochondria

the power plants of the cell

 converts the chemical energy stored in food into compounds that are more convenient for the cell to use

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Cell Wall

Many cells, including most prokaryotes, also produce a strong supporting  layer around the membrane

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lipid bilayer

gives cell membranes a flexible structure that forms 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

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Selectively Permeable

 some substances can pass across them and others cannot. Also called semipermeable membranes.

A substance is able to cross a membrane, the membrane is permeable to it

A substance not able to cross a membrane, the membrane is not permeable to it

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Diffusion

 the process by which particles move from an area of high concentration to an area of lower concentration.  Diffusion is the driving force behind the movement of many substances across.

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Faciliated diffusion

this process , in which molecules that cannot directly diffuse across the membrane pass through special protein channels

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Aquaporins

many cells contain water channel proteins, that allow water to pass right though them

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Osmosis 

the diffusion of water through a selectivity permeable. In osmosis, as in other forms of diffusion, molecules move from an area of higher concentration to an area of lower concentration. The only difference is that the molecules that move in the case of osmosis are water molecules, not solute molecules

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Isotonic

 the concentration of solutes is the same inside and outside the cell, "same strength"

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Hypertonic

The solution has a higher solute concentration than the cell., "above strength"

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Osmotic Pressure

what the net movement of water out of or into a cell produces , driven by differences in concentration

 Osmotic pressure can cause an animal cell in hypertonic solution to shrink, and one in a hypotonic solution to swell