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Myocardium

Thick middle muscle layer of the heart; pumps blood through the circulatory system

Atrium

Upper chamber of the heart that recieves and holds blood that is about to enter the ventricle

Ventricle

Lower chamber of the heart that pumps blood out of the heart

Pulmonary Circulation

Pathway of circulation between the heart and the lungs

Systemic Circulation

Pathway of circulation between the heart and the rest of the body

Valve

Flap of connective tissue between an atrium and a ventricle, or in a vein, that prevents backflow of blood

Pacemaker

Small group of cardiac muscle cells in the right atrium that "set the pace" for the heart as a whole

Aorta

A large blood vessel in mammals through which blood travels from the left ventricle to all parts of the body except the lungs

Artery

Large blood vessel that carries blood from the heart to tissues of the body

Capillary

Smallest blood vessel

Vein

A blood vessel that returns blood to the heart

Atherosclerosis

Condition in which fatty deposits called plaque build up on the inner walls of the arteries

Plasma

Straw colored fluid that makes up 55%of blood; consists of about 90% water and 10% of dissolved gases, salts, nutrients, enzymes, hormones, waste products and plasma proteins

Hemoglobin

Iron containg protein in red blood cells that transports oxygen from the lungs to the tissues of the body

Lymphocyte

Type of white blood cell that produces antibodies that help destroy pathogens

Platelet

Cell fragment released by bone marrow that helps in blood clotting

Lymph

Fluid lost by the blood in surrounding tissue

Pharynx

Muscular tube at the end of the gastrovascular cavity, or throat, that connects the mouth with the rest of the digestive tract and serves as a passageway for food and air

Trachea

Windpipe; tube through which air moves

Larynx

Structure in the throat containing the vocal cords

Bronchus

Passageway leading the trachea to a lung

Diaphram

Large, flat muscle at the bottom of the chest cavity that helps with breathing

Nicotine

Stimulant drug in tabacco that increase heart rate and blood pressure

Emphysema

Disease in which tissues of the lungs loose elasticity, which makes breathing more difficult

Energy

The strength and vitality required for sustained physical or mental activity.

Calorie

Amount of energy needed to raise the temperature of 1gram of water by 1 degrees Celsius

ATP (Adenosine Triphosphate)

One of the principal chemical compounds that living things use to store and release energy

Glycolysis

First step in releasing energy of glucose in which a molecule of of gluecose is broken into two molecules of pyruvic acid

Latic Acid Fermentation

Biological process by which sugars such as glucose, fructose, and sucrose, are converted into cellular energy

Aerobic

Process that requires oxygen

Anaerobic

Process that does not require oxygen

Kreb's Cycle

Second stage of cellular respiration, in which pyruvic acid is broken down into CO2 in a series of energy-extracting reactions

Electron Transport Chain

A series of proteins in which the high-energy electrons from the Krebs Cycle are used to convert ADP into ATP

NAD+ (NADH)

Electron carrier involved in glycolysis

ATP Synthase

Large protein that uses energy from H+ ions to bind ATP and a phosphate group together to make ATP

Cell Division

Process by which a cell divides into two new daughter cells

Mitosis

Part of the eukaryotic cell division during which the cell nucleus divides

Cytokinesis

Division of the cytoplasm during cell division

Chromosomes

Threadlike structures within the nucleus containg the genetic information that is passed from one generation to the next

Chromatin

granular material visible within the nucleus

Interphase

Period of the cell cycle between cell divisions

G1 Phase

Period where cells do most of their growing before cell divsion

S Phase

Period where cells are replicated before cell division

G2 Phase

Period where cells are checked before going through cell division

Prophase

First and longest phase of mitosis, during which the chromosomes become visable and the centrioles seperate and take up positions on the opposite sides of the nucleus

Metaphase

Second phase of mitosis, during which the chromosomes line up across the center of the cell

Anaphase

Third phase of mitosis, during which chromosomes seperate and move toward opposite poles

Telophase

Fourth and final phase of MITOSIS, during which the chromosmes begin to disperse into a tangle of the dense material

Spindle

fanlike microtube structure that helps seperate the chromosomes during mitosis

Centrioles

One of the two tiny structures in the cytoplasm of animals near the nuclear envelope

Cell Plate

Wall between the two new cells forming in mitosis

Genetics

Scientific study of heredity

Fertilization

process in sexual reproduction in which male and female reproductive cells join to form a new cell

True-breeding

Term used to describe organisms that produce offspring identical to themselves

Trait

Specific characteristic

Hybrid

Offspring of crosses between parents with different traits

Gene

Sequences of DNA that codes for a protein and thus determines a trait

Allele

One of a number of forms of a gene

Segregation

Seperation of alleles during gamete formation

Gamete

Sex cell

Probability

The likelyhood that something will occur

Punnet Square

Diagram showing the gene combinations that might result in a genetic cross

Homozygous

Organism that has two identical alleles for a trait

Heterzygous

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 the other

Codominance

Situation in which both alleles contribuate to the phenotype of the organism

Multiple Alleles

Three or more alleles for the same gene

Polygenic Traits

traits controlled by two 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 has a single set of chromosomes, therefore a single set of genes

Meiosis

Process by which the number of chromosomes per cell is cut in half through the seperation of homologous chromosomes 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 during meiosis

Gene Map

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

Karyotype

Set of photographs of chromosomes grouped in order in pairs

Sex Chromosome

One of the two chromosomes that determine and individual's sex; Male:XY Female:XX

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 of Y chromosome

Non-Disjunction

Chromosomes fail to seperate fully in meiosis

Nucleotide

Monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base

Base Pairing

Principle that bonds in DNA can form only between adenine and thymine and guanine and cytosine

Histone

Globular protein molecule around which DNA is tightly coiled in chromatin

Replication

Copying process by which a cell duplicates its DNA

DNA Polymerase

Enzyme that "proofreads" new DNA strands, helping to ensure that each molecule is a nearly perfect copy of the original DNA

Messenger RNA

RNA molecule that carries copies of instructions for the assembly of amino acids into proteins from DNA to the rest of the cell

Ribosomal RNA

Type of RNA that makes up the major part of ribosomes

Transfer RNA

Type of RNA molecule that transfers amino acids to ribosomes during protein synthesis

Transcription

Process in which part of the nucleotide sequence of DNA is copied into a complemantary strand of RNA

RNA Polymerase

Enzyme similar to DNA polymerase that binds to DNA and seperates the DNA strands during transcription

Promoter

Region of DNA that indicates to an enzyme where to bind to make RNA

Intron

Intervening sequence of DNA; does not code for a protein

Exon

Expressed sequence of DNA; codes for a protein

Codon

Three nucleotide sequence on messenger RNA that codes for a single amino acid

Translation

Decoding of mRNA message into a polypeptide chain

Anticodon

Group of three bases on a tRNA molecule that are complemantary to an mRNA codon

Evolution

Change in a kind of organism over time

Theory

A well-tested explanation that unifies a broad range of observations

Fossil

Preserved remains or evidence of an ancient organism

Natural Selection

Process by which individuals that are better suited to their environment survive and reproduce more successfully; also called survival of the fittest

Artificial Selection

Selection by humans breeding of usefult raits from the natural variation among among different organisms

Fitness

Ability of an organism to survive and reproduce in its environment

Adaptation

inherited characteristic that increases an organisms chance of survival

Struggle for Exsistence

Competition among members of a species among food, living space, and other necessities of life

Survival of the Fittest

Process by which individuals that are better suited to their environment survive and reproduce more successfully; also called natural selection

Descent with Modification

Principle that each living species has descended, with changes, from a species over time

Common Descent

Principle that all living things have a common ancestor

Homologous Structures

Structures that have different mature forms in different organisms but develope from the same embryonic tissue

Gradualism

The belief in or the policy of advancing toward a goal by gradual, often slow stages

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