any substance that dissociates in water to increase the concentration of H+ ions; pH values of acids are from 1-7
indicates concentration of hydrogen ions in a solution (the more H+ ions a solution produces, the lower its pH; pH scale- less than 7 is acidic, 7 is neutral, above 7 is basic)
when nonpolar molecules do not form hydrogen bonds with water ("fearing water")
specific groups of atoms with definite chemical properties that they retain no matter where they occur
condensation reaction in which the -OH and H groups are removed during the synthesis of a new molecule- water is removed
process in which a hydrogen atom is attached to one subunit and a hydroxyl group to the other- water is added
process in which a protein's shape is changed due to a change in its environment- pH change, temperature, or ionic concentration of surrounding solution affect it
a reaction that has a "-" heat of reaction b/c it releases more energy that it stores
a reaction that has a "+" heat of reaction and stores more energy than it releases.
Variables that effect enzyme reaction rate
Temperature, pH, enzyme concentration, substrate concentration
regulates movement of materials in and out of cells, maintains cell shape and allows cells to communicate with each other
modifies, sorts and packages substances made by the cell and sends them to vacuoles, other organelles or out of the cell
double membrane surrounding the nucleus that controls what enters and leaves the nucleus
idea that all living things are composed of cells, cells are the basic units of structure and function in living things, and new cells are produced from existing cells
network of protein filaments within some cells that helps the cell maintain its shape and is involved in many forms of cell movement
cell membranes composed of two layers of phospholipids, with the tails pointed inwards towards each other, and the heads facing outward
transport proteins helping ions and polar molecules to diffuse through the bilayer
channel proteins (pores)
tunnels that open for ions and polar molecules to pass through the cell membrane
the solute has high concentration, the water has low, water moves out of the cell
the solute and water have an equal concentration to the cell's cytoplasm, water moves into and out of the cell at equal rates
colllect excess water in unicellular eukaryotes and force the water out of the cell
a carrier protein that uses ATP to actively transport 3 sodium ions out of a cell, and 2 potassium ions into a cell
a signal molecule inside a cell, generated when a substance attaches to the outside of the cell membrane, causes changes in the cytoplasm and nucleus
in eukaryotic cells, a process of cell division that forms two new nuclei, each of which has the same number of chromosomes
organic process consisting of the division of the cytoplasm of a cell following karyokinesis bringing about the separation into two daughter cells
The complex of DNA and proteins that makes up a eukaryotic chromosome. When the cell is not dividing, it exists as a mass of very long, thin fibers that are not visible with a light microscope.
Replicated forms of a chromosome joined together by the centromere and eventually separated during mitosis or meiosis II.
a specialized condensed region of each chromosome that appears during mitosis where the chromatids are held together to form an X shape
the period of the cell cycle during which the nucleus is not undergoing division, typically occurring between mitotic or meiotic divisions
dense masses of RNA and protein that manufacture ribosomes, several of these are located in the nucleus.
first and longest phase of mitosis, during which the chromosomes become visible and the centrioles separate and take up positions on the opposite sides of the nucleus
second phase of mitosis, during which the chromosomes line up across the center of the cell
the third phase of mitosis, during which the chromosome pairs separate and move toward opposite poles
the final stage of meiosis or mitosis, in which the separated chromosomes reach the opposite poles of the dividing cell and the nuclei of the daughter cells form around the two sets of chromosomes
A double membrane across the midline of a dividing plant cell, between which the new cell wall forms during cytokinesis.
the second phase of meiosis consisting of chromatids separating, along with the two diploid cells splitting in two
The first phase of meiosis I. the replicated chromosomes condense, homologous chromsomes pair up, crossing over occurs between homologous chromosomes, the spindle is formed, and the nuclear envelope breaks apart into vesicles. the longest phase of meiosis.
The third phase of meiosis I. the replicated homologous chromosomes are separated (the tetrad is split) and pulled to opposite sides of the cell.
The second phase of meiosis I. the paired homologous chromsomes (tetrads) align at the center of the cell (the metaphase plate).
The fourth of meiosis I. the number of chromosoms is now reduced by half. After this phase the cell is considered to be haploid. Note however, that the chromosomes are still replicated, and the sister chromatids must still be separated during meiosis II.
The first phase of meiosis II. identical to the mitotic step, except that the number of chromosomes was reduced by half during meiosis I.
The second phase of meiosis II. identical to the mitotic step, except that the number of chromosomes was reduced by half during meiosis I.
The third phase of meiosis II. the sister chromatids are finally spearated at their centromeres and puled to opposite sides of teh cell. is identical to mitotic anaphase, excep the number of chromosmes was reduced by half during meiosis I.
The fourth and final phase of meiosis II. the number of chromosomes was reduced by half during meiosis. I.
term used to refer to a cell that contains only a single set of chromosomes and therefore only a single set of genes
the side by side pairing of homologous maternal and paternal chromosomes at the start of meiosis
the interchange of sections between pairing homologous chromosomes during the prophase of meiosis
checks to see if cell size is adequate; chromosomes replication is successfully completed and checks for DNA errors
if condidtions are not apporpiate for the cell to divide or if it is not programmed to divide they are in this phase
Density Dependent Inhibition
The phenomenon observed in normal animal cells that causes them to stop dividing when they come into contact with one another.
one of two alternate forms of a gene that can have the same locus on homologous chromosomes and are responsible for alternative traits
Law of Segregation
Mendel's law that states that the pairs of homologous chromosomes separate in meiosis so that only one chromosome from each pair is present in each gamete
Law of Independent Assortment
states that allele pairs separate independently during the formation of gametes
hybridization using a single trait with two alleles (as in Mendel's experiments with garden peas)
creates a blended phenotype; one allele is not completely dominant over the other
A type of gene interaction in which one gene alters the phenotypic effects of another gene that is independently inherited., One gene masks the expression of a different gene for a different trait
A single gene having multiple effects on an individuals phenotype (more than one phenotypic expression)
genes located on the same chromosome that tend to be inherited together in genetic crosses
During development, females inactivate half of their X gene elles in order to prevent producing double the amount of the protein.
error in meiosis in which homologous chromosomes don't separate; gametes end up with wrong number of chromosomes
an abnormality involving a chromosome number that is not an exact multiple of the haploid number (one chromosome set is incomplete)(causes down sydrome and turners syndrome)
the appearance of the chromosomal makeup of a somatic cell in an individual or species (including the number and arrangement and size and structure of the chromosomes)
chromosomes that have the same sequence of genes, that have the same structured, and that pair during meisosis
One of a ribosome's three binding sites for tRNA during translation. Holds the tRNA carrying the next amino acid to be added to the polypeptide chain.
A specialized base triplet at one end of a tRNA molecule that recognizes a particular complementary codon on an mRNA molecule.
A type of point mutation; the replacement of one nucleotide and its partner in the complementary DNA strand by another pair of nucleotides.
A three-nucleotide sequence of DNA or mRNA that specifies a particular amino acid or termination signal; the basic unit of the genetic code.
1) A deficiency in a chromosome resulting from the loss of a fragment through breakage. (2) A mutational loss of one or more nucleotide pairs from a gene.
One of a ribosome's three binding sites for tRNA during translation. The place where discharged tRNAs leave the ribosome.
A mutation occurring when the number of nucleotides inserted or deleted is not a multiple of three, resulting in the improper grouping of the following nucleotides into codons.
messenger RNA (mRNA)
A type of RNA, synthesized from DNA, that attaches to ribosomes in the cytoplasm and specifies the primary structure of a protein.
The most common type of mutation, a base-pair substitution in which the new codon makes sense in that it still codes for an amino acid.
A mutation that changes an amino acid codon to one of the three stop codons, resulting in a shorter and usually nonfunctional protein
one gene-one polypeptide hypothesis
The premise that a gene is a segment of DNA that codes for one polypeptide.
One of a ribosome's three binding sites for tRNA during translation. Holds the tRNA carrying the growing polypeptide chain. (P stands for peptidyl tRNA
The modified end of the 3' end of an mRNA molecule consisting of the addition of some 50 to 250 adenine nucleotides.
An initial RNA transcript; also called pre-mRNA when transcribed from a protein-coding gene
A specific nucleotide sequence in DNA that binds RNA polymerase and indicates where to start transcribing RNA
A cell organelle constructed in the nucleolus and functioning as the site of protein synthesis in the cytoplasm; consists of rRNA and protein molecules, which make up two subunits.
An enzyme that links together the growing chain of ribonucleotides during transcription.
The removal of noncoding portions (introns) of the RNA molecule after initial synthesis.
signal-recognition particle (SRP)
A protein-RNA complex that recognizes a signal peptide as it emerges from the ribosome.
A complex assembly that interacts with the ends of an RNA intron in splicing RNA, releasing the intron and joining the two adjacent exons.
The DNA strand that provides the template for ordering the sequence of nucleotides in an RNA transcript.
In prokaryotes, a special sequence of nucleotides in DNA that marks the end of a gene. It signals RNA polymerase to release the newly made RNA molecule, which then departs from the gene.
transfer RNA (tRNA)
An RNA molecule that functions as an interpreter between nucleic acid and protein language by picking up specific amino acids and recognizing the appropriate codons in the mRNA.
The synthesis of a polypeptide using the genetic information encoded in an mRNA molecule. There is a change of languagefrom nucleotides to amino acids
DNA molecules formed when segments of DNA from two different sources are combined in vitro
enzymes naturally occurring in bacteria, cut DNA molecules at a limited number of specific locations
sequence of DNA 4-8 nucleotides long, symmetrical where the restriction enzyme cuts
gene on plasmid; if bacterium has this plasmid, will be able to grow on agar with ampicillin. If does not have plasmid, will not grow on agar with amp.
gene part of the lac operon. If gene is intact, produces a product that can break down lactose and Xgal, colony will be blue. If not intact, will not break down Xgal, colony will be white.
Step 5 bacterial transformation
put the plasmids into bacteria with no functioning lacZ gene. Use heat or high Ca2+ to stimulate transformation
complete set of plasmid-containing cell clones, each carrying copies of a particular segment from the original genome
Step 1 gel electrophoresis
cut DNA with restriction enzyme, put sample in well of chamber, let fragments "run," add dye so you can see DNA, observe with UV light
mRNA - function and structure
provides the instructions for assembling amino acids into a polypeptide chain; linear; nucleotides are codons
tRNA - function and structure
short RNA molecule; transports amino acids to their proper place; "clover-leaf" shaped; nucleotides are anticodons
rRNA -function and structure
building blocks of ribosomes; DNA is transcribed into rRNA in the nucleolus; globular
Process in which unzipped DNA strands serve as templates for complementary strands. Occurs during interphase of the cell cycle.
DNA replication; each double-stranded molecule of DNA consists of a single strand of old DNA and a single strand of new, replicated DNA.
single strand binding protein
protein that attaches to each strand of uncoiled DNA during DNA replication to keep the strands separate
enzyme that assembles the new DNA strand in DNA replication. Moves in 3' to 5' direction.
Short segments of complementary DNA formed when DNA polymerase assembles DNA on the 5' to 3' strand; caused b/c polymerase must return to replication fork after each segment. Connected by DNA ligase.
Connects Okazaki segments formed during DNA replication on the 5' to 3' template strand.
The 5' to 3' template strand of DNA replication. Takes longer to assemble, and so "lags" behind the 3' to 5' strand.
A short segment of RNA nucleotides that begins, in DNA replication, the leading strand as well as every Okazaki segment on the lagging strand. Enables DNA polymerase to attach DNA nucleotides to the primer.
enzyme which attaches itself to the end of the template strand in DNA replication to extend the strand by adding a short sequence of DNA nucleotides over and over again. Prevents loss of preceding coding DNA.
the gene is a DNA segment that codes for a particular polypeptide.
the gene is a DNA segment that codes for a particular enzyme. Proven false and replaced with one-gene-one-polypeptide hypothesis.
a step of protein synthesis in which RNA molecules are created by using DNA molecules as a template
three adjacent nucleotides on tRNA which base pair with the codon of the mRNA during translation.
Allows anticodons of some tRNAs to base-pair with more than one type of codon, because exact base pairing between the third nucleotide of the anticodon and codon are usually not required.
RNA polymerase attaches to the promoter region on the DNA and begins to unzip the DNA into two strands.
the nucleotide sequence T-A-T-A; often occurs in the promoter region during mRNA transcriptions.
RNA polymerase unzips the DNA and assembles RNA nucleotides using one strand of DNA as a template.
RNA polymerase reaches a special sequence of nucleotides that serves as a termination point. In eukaryotes, the termination region contains the DNA sequence AAAAAA.