Biology Final

Polarity

Molecules having uneven distribution of charges

Cohesion

Attraction between molecules of the same substance

Adhesion

An attraction between molecules of different substances

Capillarity

the attraction between molecules that results in the rise of a liquid in small tubes

surface tension

A measure of how difficult it is to stretch or break the surface of a liquid

hydrogen bond

weak attraction between a hydrogen atom and another atom

Solution

A homogeneous mixture of two or more substances

Solute

A substance that is dissolved in a solution.

Solvent

the substance in which the solute dissolves

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

Why does diffusion happen?

Because the particles move randomly and spread out

Osmosis

Diffusion of water through a selectively permeable membrane

passive transport

the movement of substances across a cell membrane without the use of energy by the cell

active transport

Energy-requiring process that moves material across a cell membrane against a concentration difference

Kinetic Engery

energy of motion

concentration gradient

difference in the concentration of a substance from one location to another

Equilibrium

a state in which opposing forces or influences are balanced.

selectivly permeable

when certain types of substances pass through the cell membrane more easily then others

turgor pressure

The pressure that water molecules exert against the cell wall

Gregor Mendel's work

He crossed different strains of purebred plants and studied their offspring

recessive trait

a genetic factor that is blocked by the presence of a dominant factor

dominant trait

a genetic factor that blocks another genetic factor

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

the law that states that genes separate independently of one another in meiosis

Genotype

genetic makeup of an organism

Phenotype

An organism's physical appearance, or visible traits.

Homozygous

An organism that has two identical alleles for a trait

Heterozygous

An organism that has two different alleles for a trait

Probability Equation

(Number of desired outcomes) / (Total number of outcomes)

incomplete dominance

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

Codominance

A condition in which neither of two alleles of a gene is dominant or recessive.

Punnett Square

A chart that shows all the possible combinations of alleles that can result from a genetic cross

dihybrid cross

A cross between individuals that have different alleles for the same gene

ABO blood typing

Method of identifying blood as either type A, B, or O based on the antibodies and antigens.

crossing over

Process in which homologous chromosomes exchange portions of their chromatids during meiosis.

Antigen

substance that triggers an immune response

antibody

A protein that acts against a specific antigen

sex chromosomes

Chromosomes that determine the sex of an individual (Male: XY, Females: XX)

Autosomes

Any chromosome that is not a sex chromosome

sex-linked traits

Traits controlled by genes located on sex chromosomes.

Carrier

A person whose genotype includes a gene that is not expressed in the phenotype.

Genetic disorder

an inherited disease or disorder that is caused by a mutation in a gene or by a chromosomal defect

multipule alleles

A gene that has more than two alleles

Karyotype

A display of the chromosome pairs of a cell arranged by size and shape.

Heredity

the transmission of traits from one generation to the next

Genes

Chemical factors that determine traits

Alleles

Different forms of a gene

Trait

A characteristic that an organism can pass on to its offspring through its genes.

P generation

Parental generation, the first two individuals that mate in a genetic cross

F1 generation

the first generation of offspring obtained from an experimental cross of two organisms

F2 generation

offspring of the F1 generation

DNA

A complex molecule containing the genetic information that makes up the chromosomes.

RNA

A single-stranded nucleic acid that passes along genetic messages

Replication

process of copying DNA prior to cell division

When does replication occur?

S phase of interphase

Transcription

synthesis of an RNA molecule from a DNA template

mRNA

messenger RNA; type of RNA that carries instructions from DNA in the nucleus to the ribosome

tRNA

transfer RNA; type of RNA that carries amino acids to the ribosome

rRNA

ribosomal RNA; type of RNA that makes up part of the ribosome

Translation

Process by which mRNA is decoded and a protein is produced

Chargaff's Rules

A\=T and C\=G

Franklin and Wilkins

Used X ray diffraction to take pictures of DNA structure; discovered two forms of DNA

Watson and Crick

Developed the double helix model of DNA.

gene regulation

ability of an organism to control which genes are transcribed in response to the environment

lac operon

a gene system whose operator gene and three structural genes control lactose metabolism in E. coli

Barr bodies

inactivated X chromosomes found only in females

Virus

A tiny, nonliving particle that invades and then reproduces inside a living cell.

Nucleotide

A building block of DNA, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group.

Deoxyribose

A five-carbon sugar that is a component of DNA nucleotides

nitrogenous base

A molecule found in DNA and RNA that encodes genetic information in cells.

Purine

double-ring nitrogenous base

Pyrimidine

single-ring nitrogenous base

Adenine

The base that pairs with Thymine in DNA

Guanine

The base that pairs with Cytosine in DNA

Cytosine

The base that pairs with Guanine with DNA

Thymine

The base that pairs with Adenine in DNA

Uracil

Nitrogen base that pairs with adenine in RNA.

Double helix

Shape of DNA

covalent bond

A chemical bond formed when two atoms share electrons

Hydrogen bond

weak attraction between a hydrogen atom and another atom

complementary base pairs

Hydrogen bonding between particular pyrimidines and purines. Adenine & Thymine. Cytosine & Guanine.

S phase

The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated.

Helicases

enzymes that untwist the double helix at the replication forks

Replication fork

A Y-shaped region on a replicating DNA molecule where new strands are growing.

DNA polymerase

Enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule

semi-conservative replication

in each new DNA double helix, one strand is from the original molecule, and one strand is new

Mutation

A random change in a gene or chromosome.

protien synthesis

formation of protiens by using information contained in DNA and carried by mRNA

Ribose

A five-carbon sugar present in RNA

RNA polymerase

enzyme that links together the growing chain of RNA nucleotides during transcription using a DNA strand as a template

Genetic code

collection of codons of mRNA, each of which directs the incorporation of a particular amino acid into a protein during protein synthesis

Codon

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

Anticodon

group of three bases on a tRNA molecule that are complementary to an mRNA codon

Amino acid

Building blocks of protein

Peptide bond

covalent bond formed between amino acids

Polypeptide

long chain of amino acids that makes proteins

Protien

Chains of amino acids

E.coli

Bacteria found in animal and human intestines.

Specialized

Having one use among many possible uses

repressor protein

a protein that inhibits genes from being expressed