Biology Study Guide 1st Semester

Science

• An organized way of using evidence to learn about the natural world.

Observation

• The process of gathering information about events or process in a careful, orderly way.

Data

• The information gathered from an observation, or experiment.

Inference

• A logical interpretation of events based on prior knowledge or experiences.

Hypothesis

• A proposed scientific explanation for a set of observations.

Spontaneous Generation

• Life arising from nonliving matter. Frog and fish come from mud in a pond.

Controlled Experiment

• A type of experiment where only one variable is changed at a time.

Manipulated Variable

• A variable in an experiment that is deliberately changed.

Responding Variable

• A variable that is observed and that changes in response to the manipulated variable.

Theory

• Evidence from numerous investigations build up of data from investigations.

Biology

• The science that employs the scientific method to study living things. A way to explain the natural world.

Homeostasis

• Living things maintain a stable internal environment.

Sexual Reproduction

• Cells from two different parents unite to form the first cell of the new organism.

Asexual Reproduction

• When a single parent produces offspring that are identical to itself.

Metabolism

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

Stimulus

• A signal to which an organism responds.

Metric System

• A decimal system of measurement whose units are based on certain physical standards and are scaled on multiples of 10.

Microscope

• Devices that produce magnified images of structures that are too small to see with the unaided eye.

Compound Light Microscope

• Allows light to pass through the specimen and uses two lenses to form an image.

Electronic Microscope

• Use beams of electrons, rather than light, to produce images of specimen.

Cell Culture

• Cells that are able to reproduce, outside of the organism.

Cell Fractionation

• To separate the different cell parts.

Atom

• Basic unit of matter.

Neutron

• A neutral charged particle of an atom located in the nucleusl

Nucleus

• Strong forces bind protons and neutrons together in a central space in the atom

Electron

• A negatively charges particle with 1/1840 the mass of a proton.

Element

• A pure substance that consists entirely of one type of atom.

Isotope

• Atoms of the same element that differ in the number of neutrons they contain.

Compound

• A substance formed by the chemical combination of two or more elements in definite proportions.

Ionic Bond

• Formed when one or more electrons are transferred from one atom to another.

Ion

• Positively and negatively charged atoms.

• Cation are + charged, lost electrons

• Anions are – charged, gained electrons

Covalent Bond

• Forms when electrons are shared between atoms.

Molecule

• The smallest unit of most compounds.

Van Der Waals Force

• Chemists call such intermolecular forces of attractions between atoms.

Cohesion

• An attraction between molecules of the same substance.

Adhesion

• An attraction between molecules of different substances.

Mixture

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

Solution

• In a mixture where one thing is dissolved in another.

Solute

• The substance that is dissolved.

Solvent

• The substance in which the solute dissolves.

• The univeral solvent is water

Suspension

• Mixtures of water and non-dissolved material.

pH Scale

• To indicate the concentration of Hydronium (H+) ions in a solution.

• The reciprocal log of the hydronium ion concentration

Acid

• Any compound that forms H ions in a solution.

• Sulfuric acid, hydrochloric acid, nitric acid, acetic acid

Base

• A compound that produces hydroxide ions in a solution.

• Sodium hydroxide, calcium hydroxide. Magnesium hydroxide

Buffer

• Weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes.

Monomer

• Smaller units, base units

• Saccharide make up starches, nucleotides make up Nucleic acids, amino acids make up proteins

Polymer

• Monomers that are joined together, to form a larger compound

Lipid

• Made mostly from carbon and hydrogen atoms.

Nucleic Acid

• Macromolecules containing hydrogen, oxygen, nitrogen, carbon, and phosphorus.

Nucleotide

• Consists of three parts– A 5 carbon sugar

– A phosphate group

– A nitrogenous base.

Ribonucleic Acid

• RNA contains the sugar ribose.

Deoxyribonucleic Acid

• DNA contains the sugar deoxyribose.

Protein

• Macromolecules that contain nitrogen as well as carbon, hydrogen, and oxygen.

Amino Acid

• Proteins that are polymers of molecules.

Chemical Reaction

• A process that changes or transforms one set of chemicals into another.

Reactant

• The elements or compounds that enter into a chemical reaction.

Product

• Elements or compounds produced by a chemical reaction.

Activation Energy

• Energy that is needed to get a reaction started.

Catalyst

• A substance that speeds up the rate of a chemical reaction.

Enzyme

• Proteins that act as biological catalysts.

Substrate

• The reactants of enzyme catalyzed reactions.

Cell

• The basic units of life.

Cell Theory

• A fundamental concept of biology.

Nucleus

• A large membrane enclosed structure that contains the cells genetic material in the form of DNA.

Eukaryote

• Cells that contain nuclei.

Prokaryote

• Cells that do not contain nuclei.

Organelle

• Organs that can be all different sizes and types.

Cytoplasm

• The portion of the cell outside the nucleus.

Nuclear Envelope

• Composed of two membranes.

Chromatin

• The granular material you can see in the nucleus.

Chromosome

• When a cell divides the chromatin condenses to form a chromosome.

Nucleolus

• Where the assembly of ribosomes begins.

Ribosome

• Small particles of RNA and protein found throughout the cytoplasm.

Endoplasmic Reticulum

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

Golgi Apparatus

• To modify, sort, and package proteins storage in the cell or secretion outside the cell.

Lysosome

• Small organelles filled with enzymes.

Vacuole

• Stores materials such as water, salts, proteins, and carbohydrates.

Mitochondrion

• Organelles that convert the chemical energy stored in food into compounds that are more convenient for the cell to use.

Chloroplast

• Organelles that capture the energy from sunlight and convert it into chemical energy.

Cytoskeleton

• A network of protein filaments that helps the cell to maintain its shape.

Centriole

• Located near the nucleus and helps to organize cell division.

• Composed of 9 microtubules

Cell Membrane

• Regulates what enters and leaves the cell and also provides protection and support

Cell Wall

• A strong supporting layer around the membrane, that is water proof and gives the cell a ridged structure.

• In plants cell this is made of cellulose• In fungi cells this is made of chitin.

Lipid Bilayer

• a doubled layer sheet that makes up the cell membrane

Concentration

• The mass of solute in a given volume of solution or mall/volume

Diffusion

• Where the particles are even distributed within a space or material.

• Goes from an area of higher concentration to an area of lower concentration

Equilibrium

• A concentration of the solute is the same throughout a system

Osmosis

• The passage of water through a selectively permeable membrane form an area of higher concentration to an area of lower concentration.

Isotonic

• The solution to cell ratio has equal water molecules and the cell.

• Ringers solution, Human Physiological saline, eye drops-Same concentration of water molecules as the cells have.

Hypertonic

The solution to cell ratio has more water molecules than the cell.

The cell will allow water to flow in and burst.

Hypotonic

• The solution to cell ratio has fewer water molecules than the cell.

• Cell will shrink due to diffusion trying to balance out the water molecules.

Facilitated Diffusion

• Diffusion of molecules, such as glucose, across a membrane using a protein carrier molecule

Active Transport

• Cells move materials in the opposite direction against concentration differences. Using cell energy, a carrier molecule

Endocytosis

• The process of taking material into the cell by means of infoldings or pockets of the cell membrane

Phagocytosis

• Extensions of cytoplasm surround a particle and package it within a food vacuole. Engulfing

Pinocytosis

• Process by which a cell takes in liquid from the surrounding environment. Cell drinking

Exocytosis

• Process by which a cell releases large amounts of material

Cell Specialization

• The process in which cells develop in different ways to preform different tasks

Tissue

• Group of similar cells that preform a particular function

Organ

• Group of tissues that work together to preform closely related functions.

Organ System

• Group of organs that work together to preform a specific function

• 12 human body organ systems. Nervous, endocrine, respiratory, digestive, reproductive, excretory, skeletal, muscular, intergumentary (skin), immune, circulatory, special senses.

Cell Division

• Process by which a cell divides into two new daughter cells.

• Process that produces two clones of the original parent.

• Produces identical cells very quickly.

Cytokinesis

• Division of the cytoplasm during the last step of cell division

Chromatids

• One of two identical sister parts of a duplicated chromosome

Centromere

• Area where the chromatids of a chromosome are attached together

Cell Cycle

• Series of events that cells go through as they grow and divide

• G-1-interphase, cell does most of it daily work• S-1-chromosomes duplicate• G-2-the rest of the cells oprganelles gear up

for mitosis• M-1-Mitosis• Cytokinesis

Centriole

• Area where the chromatids of a chromosome are attached to the spindle.

Spindle

• Fanlike microtubule structure that helps separate the chromosomes during mitosis

• Only found in animal cells

Cyclin

• One of a family of closely related proteins that regulate the cell cycle in eukaryotic cells

Cancer

• Disorder in when some of the body’s own cells lose the ability to control growth

• Cells growing out of control

Genetics

• Scientific study of heredity, how traits are passed down from one generation to the next.

Fertilization

• Process in sexual reproduction in which male and female reproductive cells join to form a new cell (zygote).

True-breeding

• Term used to describe organisms that produce offspring identical to themselves if allowed to self pollinate

Trait

• Specific characteristic that varies from one individual to another

Hybrid

• Off spring of crosses between parents with different traits

Gene

• Sequence of DNA that codes for a protein and thus determines a trait

Allele

• One of a number of different forms of a gene• The ways that a gene may be expressed.

Segregation

• Separation of alleles during gamete formation

Gamete

• Specialized cell involved in sexual reproduction

Probability

• Likely hood something’s going to happen

Punnett Square

• Diagram showing the gene combination that might result from a genetic cross

Homozygous

• Terms used to refer to an organism that has two identical alleles for a particular trait

Heterozygous

• Term used to refer to an organism that has two different alleles for the same trait

Phenotype

• Physical characteristics of an organism

Genotype

• Genetic makeup of an organism

Independent Assortment

• Independent segregation of genes during the formation of gametes

Incomplete Dominance

• Situation in which one allele is not completely dominant over another

Codominance

• Situation in which both alleles of a gene contribute to the phenotype of the organism

Multiple Alleles

• 3 or more alleles of the same gene

Polygenic Traits

• Trait controlled by 2 or more genes

Homologous

• Term used to refer to chromosomes that each have a corresponding chromosome from the opposite sex parent

Diploid

• Term used to refer to a cell that contains both sets of homologous chromosomes

Haploid

• Term used to refer to a cell that contains only a single set of chromosomes and therefore only a single set of genes

Meiosis

• Process by which the number of chromosomes per cell is cut in half through the separation of homologous chromosome in a diploid cell

Tetrad

• Structure containing 4 chromatids that forms during meiosis

Crossing-over

• Process in which homologous chromosomes exchange portions of their chromatids diring meiosis

Gene Map

• Diagram showing the relative locations of each known gene on a particular chromosome

Karyotype

• Photograph of chromosomes grouped in order in pairs

Sex Chromosomes

• One of the two chromosomes that determine an individual’s sex

Autosome

• Chromosome that is not a sex chromosome

Pedigree

• Chart that shows the relationships within a family

Sex-linked Gene

• Gene located on the x or y chromosome

Non Disjunction

• Error in meiosis in which homologous chromosomes fail to separate, either Metaphase I or II. Resulting in either a monosomy or a trisomy in an offspring

Trisomy

• The individual has an extra chromosome due in most cases to nondisjunction

• Trisomy 21 is an example

Triploidy

• The individual has a one complete extra set of chromosomes.

• Organism would have a 3n chromosome number-Human 2n 46 chromosomes, 3n would be 69 chromosomes

Monosomy

• A situation where an organism has one less chromosome.

• Turner Syndrome-X0

DNA Fingerprinting

• Analysis of sections of DNA that have little or no known function

Taxonomy

• Discipline of classifying organisms and assigning each organism a universally accepted name

Binomial nomenclature

• Classification system in which each species is assigned a two part scientific name

Genus

• A group of similar species that all have similar traits

Taxon

• A species or grouping in classification

Family

• Group of genera that share many characteristics

Order

• Group of similar families

Class

• Group of similar orders

Phylum

• Group of closely related classes

Kingdom

• A large taxonomic group, consisting of closely related phyla

Phylogeny

• The study of evolutionary relationships among organisms

Evolutionary Classification

• Method of grouping organisms together according to their evolutionary history

Derived Character

• Characteristic that appears in recent parts of a lineage

Cladogram

• Diagram that shows the evolutionary relationships among a group of organisms

Molecular Clocks

• Model that uses DNA comparisons to estimate the length of time that two species have been evolving independently

Domain

• Most inclusive taxonomic category; larger than a kingdom

Bacteria

• Domain of unicellular prokaryotes that have cell walls containing peptidoglycan

Eubacteria

• Kingdom of unicellular prokaryotes whose cell walls are made up of peptidoglycan

Archaea

• Domain of unicellular prokaryotes that have a cell wall that does not contain peptidoglycan

Archaebacteria

• Kingdom of unicellular prokaryotes whose cell walls that do not contain peptidoglycan

Eukarya

• Domain of all organisms whose cells have nuclei including protests plants fungi

Protista

• Kingdom composed of eukaryotes that are not classified as plants, animals, or fungi

Fungi

• Kingdom composed of heterotrophs; many obtain energy and nutrients from dead organic matter

Plantae

• Kingdom of multicellular photosynthetic autotrophs that have cell walls containing cellulose

Animalia

• Kingdom of multicellular eukaryotic heterotrophs whose cells do not have cell walls