Carbon
the element that is the chemical basis for all life on earth.
Evolution
the process by which species gradually change over time.
Natural Selection
process by which individuals that are better suited to their environment survive and reproduce most successfully; also called survival of the fittest.
variation
Differences between members of the same species.
heritable
A characteristic that is passed from parent to offspring genetically.
Reproductive Advantage
Some variations allow the organism that possesses them to have more offspring than the organism that does not possess them.
Environment
All of the surrounding things, conditions, and influences affecting the growth or development of living things.
Sexual Selection
A form of selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates.
Genome
The complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes., the full set of genetic information that an organism carries in its DNA.
Nucleus
the organelle that contains the DNA and controls the processes of the cell.
Chromosome
coiled, rod-shaped structures made of DNA and proteins found in the nucleus.
DNA
the material that contains the information that determines inherited characteristics, a long linear polymer found in the nucleus of a cell and formed from nucleotides and shaped like a double helix.
Double Helix
shape of a DNA molecule formed when two twisted DNA strands are coiled into a springlike structure and held together by hydrogen bonds between the bases.
Adenine
nitrogen base found in DNA and RNA; pairs with thymine in DNA and with uracil in RNA.
Guanine
one of the four bases that combine with sugar and phosphate to form a nucleotide subunit of DNA; guanine pairs with cytosine.
Thymine
nitrogen base found ONLY in DNA that pairs with adenine.
Cytosine
a base found in DNA and RNA and derived from pyrimidine; pairs with guanine.
Transcription
process of copying a nucleotide sequence of DNA to form a complementary strand of mRNA.
DNA to mRNA
mRNA
messenger RNA; type of RNA that carries instructions from DNA in the nucleus to the ribosome. , Carries the genetic code for a protein from the nucleus to the ribosomes where the proteins are assembled.
Ribosome
a small grain-like structure in the cytoplasm of a cell where proteins are made.
Translation
decoding of a mRNA message into a polypeptide chain.
tRNA
transfer RNA; type of RNA that carries amino acids to the ribosome.
Amino Acid
basic building blocks of protein molecules.
Protein
A molecule that is made up of amino acids and that is needed to build and repair body structures and to regulate processes in the body.
Mutation
change in a DNA sequence that affects genetic information.
Gamete
a haploid reproductive cell that unites with another haploid reproductive cell to form a zygote., egg or sperm sex cell that contains a single set of chromosomes, one from each homologous pair.
Haploid
term used to refer to a cell that contains only a single set of chromosomes and therefore only a single set of genes.
Fertilization
the joining of a sperm cell and an egg cell. , The union of haploid gametes to produce a diploid zygote.
Diploid
Cell that has two copies of each chromosome, one from an egg and one from a sperm.
Meiosis
cell division that produces reproductive cells in sexually reproducing organisms, a process in cell division during which the number of chromosomes decreases to half the original number by two divisions of the nucleus, which results in the production of s
Interphase
first stage of the cell cycle, during which a cell grows, matures, and replicates its DNA
Prophase I
1. homologous chromosomes pair up
2. each chromosomes consists of 2 sister chromatids
3. nuclear envelope disapears
4. spinlde fibers form
5.
crossing over occurs
Crossing Over
process in which homologous chromosomes exchange portions of their chromatids during meiosis.
Metaphase I
Spindle fibers attach to the chromosomes. The chromosomes then line up across the center of the cell.
Anaphase I
Spindle fibers pull each homologous chromosome pair toward opposite ends of the cell.
Telophase I
stage in meiosis; cell splits (cytokinesis) and is now haploid; chromosomes disappear, nuclear envelope forms.
Cytokinesis
The final stage of the cell cycle, in which the cell's cytoplasm divides, distributing the organelles into each of the two new cells.
Genes
sequence of DNA that codes for a protein and thus determines a trait.
Alleles
different versions of a gene.
Dominant
describes a trait that covers over, or dominates, another form of that trait.
Recessive
describes a trait or an allele that is expressed only when two recessive alleles for the same characteristic are inherited.
Phenotype
The physical traits that appear in an individual as a result of its gentic make up.
Genotype
genetic makeup of an organism.
Heterozygous
term used to refer to an organism that has two different alleles for the same trait.
Homozygous
term used to refer to an organism that has two identical alleles for a particular trait.
Incomplete Dominance
creates a blended phenotype; one allele is not completely dominant over the other.
Co-dominance
Situation in which both alleles of a gene contribute to the phenotype of the organism.
Law of independent assortment
Mendelian principle stating that genes for different traits are inherited independently of each other.
Sex linked traits
traits controlled by genes located on the X chromosome.
X chromosome
the sex chromosome found in both men and women. females have two x chromosomes; males have one. an x chromosome from each parent produces a female child.
Y chromosome
The sex chromosome found only in males. When paired with an X chromosome from the mother, it produces a male child.
Heterotroph
organism that obtains energy from the foods it consumes; also called a consumer. , an organism that cannot make its own food.
Cellular Respiration
process that releases energy by breaking down glucose and other food molecules in the presence of oxygen.
Mitochondria
powerhouse of the cell, produces energy (ATP) from oxygen and sugar(Cellular respiration)
Glycolysis
the splitting in half of a glucose molecule; the first stage of cellular respiration and fermentation.
Glucose
the form of sugar that circulates in the blood and provides the major source of energy for body tissues.
Electron bond
Covalent bonds involve the "sharing of electrons" to form "electron pairs.
ATP
one of the principal chemical compounds that living things use to store and release energy.
ADP
(Adenosine Diphosphate) The compound that remains when a phosphate group is removed from ATP, releasing energy. , a lower-energy molecule that can be converted into ATP by the addition of a phosphate group.
Phosphate
Substance added to ADP to form ATP.
krebs cycle
A chemical cycle involving eight steps that completes the metabolic breakdown of glucose molecules to carbon dioxide; occurs within the mitochondrion; the second major stage in cellular respiration.
Carbon Dioxide
A waste gas produced during cellular respiration in animals. Plants use carbon dioxide during photosynthesis.
Electron Transport Chain
a series of proteins in which the high-energy electrons from the Krebs cycle are used to convert ADP into ATP.
NADH
electron carrier that stores energy used to make ATP.
NAD
Electron carrier involved in glycolysis.
FADH2
produced in the Krebs cycle, it is a reduced form of FAD, it is an electron carrier capable of creating 2 ATP from releasing its electrons to the electron transport chain
FADH
the reduced form of FAD; an electron-carrying molecule that functions in cellular respiration, gives up electrons to the electron transport chain.
Aerobic
requires oxygen.
Anaerobic
without oxygen.
Alcohol Fermentation
the process by which certain cells convert pyruvic acid or pyruvate from glycolysis into ethyl alcohol and carbon dioxide in the abscence of oxygen.
Lactic Acid Fermentation
process where ATP is produced when muscles run out of oxygen during vigorous activity. , an anaerobic form of respiration in which sugars are converted into cellular energy and lactic acid.
Autotroph
an organism that makes its own food.