Honors Biology Review

Flashcards for reviewing key vocabulary terms in Honors Biology.

Biotic Factor

A factor that is living or was once living in an ecosystem.

Abiotic Factor

A non-living factor in an ecosystem.

Keystone Species

A species that has a disproportionately large effect on its environment relative to its abundance.

Competition

An interaction where different organisms are in pursuit of the same resources.

Predation

An interaction where one organism kills and consumes another.

Symbiosis

A close ecological relationship between two or more organisms of different species that live in direct contact with one another.

Mutualism

A type of symbiosis where both organisms benefit.

Commensalism

A type of symbiosis where one organism benefits and the other is neither harmed nor helped.

Parasitism

A type of symbiosis where one organism benefits and the other is harmed.

Food Web

Illustrates the flow of energy and nutrients in an ecosystem, interconnected food chains.

Food Chain

A sequence of organisms in which each feeds on the one below.

Producer

An organism that makes its own food, typically through photosynthesis.

Carnivore

An organism that eats only meat.

Omnivore

An organism that eats both plants and animals.

Scavenger

An organism that feeds on dead or decaying organic matter.

Herbivore

An organism that eats only plants.

Primary Consumer

An organism that consumes producers.

Secondary Consumer

An organism that eats primary consumers.

Tertiary Consumer

An organism that eats secondary consumers.

Carbohydrates

Macromolecules made of carbon, hydrogen, and oxygen atoms.

Monosaccharide

The simplest form of a carbohydrate; a monomer.

Disaccharide

A double sugar, consisting of two monosaccharides joined by dehydration synthesis.

Polysaccharide

A complex carbohydrate made up of many monosaccharides.

Dehydration Synthesis

The process of building a polymer by removing a water molecule.

Hydrolysis

The process of breaking down a polymer by adding a water molecule.

ATP

Adenosine Triphosphate, a molecule that carries energy within cells.

Photosynthesis Equation

6CO2 + 6H2O -> C6H12O6 + 6O2

Chloroplast

The organelle where photosynthesis occurs.

Grana/Granum

Stacks of thylakoids inside the chloroplast.

Stroma

The fluid-filled space surrounding the grana inside a chloroplast where the Calvin cycle takes place.

Thylakoid

A disc-shaped sac in the chloroplast where the light-dependent reactions of photosynthesis take place.

Light Reaction

The first stage of photosynthesis where light energy is converted to chemical energy, producing ATP and NADPH.

Dark Reaction (Calvin Cycle)

The second stage of photosynthesis where carbon dioxide is fixed and converted into glucose.

NADP+/NADPH

A molecule that carries hydrogen ions and electrons from the light-dependent reactions to the Calvin cycle; an electron carrier.

Rubisco

The enzyme that catalyzes the first step of the Calvin cycle (carbon fixation).

Cell Specialization

The process by which cells become specialized in structure and function.

Asexual Reproduction

Reproduction involving only one parent, producing genetically identical offspring.

Sexual Reproduction

Reproduction involving two parents, producing genetically diverse offspring.

Mitosis

The process of cell division that results in two identical daughter cells.

Interphase

The period of the cell cycle between cell divisions.

G0 Phase

A period in the cell cycle where cells exist in a quiescent state.

Chromosome

A structure of nucleic acids and protein that carries genetic information in the form of genes.

Centromere

The point on a chromosome by which it is attached to a spindle fiber during cell division.

Sister Chromatid

Either of the two identical copies of a single replicated chromosome that are joined at the centromere.

Chromatin

The material of which chromosomes of organisms other than bacteria (i.e., eukaryotes) are composed. It consists of protein, RNA, and DNA.

Homologous Chromosome

Chromosomes with the same genes, one from each parent.

Haploid Cell

A cell that contains one set of chromosomes (n).

Diploid Cell

A cell that contains two sets of chromosomes (2n).

Crossing Over

The exchange of genes between homologous chromosomes, resulting in a mixture of parental characteristics in offspring.

Meiosis

A type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell, as in the production of gametes.

Gregor Mendel

An Austrian monk and biologist whose work on pea plants established the laws of heredity.

Principle of Dominance

States that one allele is dominant over the other, the trait of the dominant allele will be expressed.

Law of Segregation

States that allele pairs separate during gamete formation, and each gamete randomly receives one allele.

Law of Independent Assortment

States that genes for different traits are sorted separately from one another so that the inheritance of one trait is not dependent on the inheritance of another.

Gene

A unit of heredity that is transferred from a parent to offspring and is held to determine some characteristic of the offspring.

Allele

One of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.

Homozygous

Having two identical alleles of a gene.

Heterozygous

Having two different alleles of a gene.

Dominant

The allele that masks the effect of another allele.

Recessive

The allele that is masked by the effect of another allele.

Genotype

The genetic constitution of an individual organism.

Phenotype

The set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.

Incomplete Inheritance

A form of inheritance wherein one allele for a specific trait is not completely dominant over the other allele. This results in a third phenotype where the expressed physical trait is a combination of both alleles.

Codominance

A relationship between two versions of a gene. Individuals receive one version of a gene, called an allele, from each parent. If the alleles are different, the dominant allele will be expressed, while the effect of the other allele, called recessive, is masked. In codominance, however, neither allele is recessive and the phenotypes of both alleles are expressed.

Multiple Alleles

Genes with more than two alleles.

Polygenic Traits

The determination of a characteristic by more than one gene.

Sex-Linked Genes

A gene located on a sex chromosome.

Carrier

A person or other organism that has inherited a recessive allele for a genetic trait or mutation but does not display that trait or show symptoms of the disease.

Pedigree

A chart that shows the inheritance of a trait in a family.

Chargaff

An Austrian-American biochemist who discovered two rules concerning the relative quantities of the four nitrogenous bases.

Franklin

An English chemist and X-ray crystallographer whose work was central to the understanding of the molecular structures of DNA.

Pauling

An American chemist and peace activist who was one of the most influential chemists in history.

Watson & Crick

American molecular biologist, who with the English physicist Francis Crick, co-discovered the structure of DNA.

Monomer of DNA

A compound consisting of a nucleoside linked to a phosphate group. Nucleotides form the basic structural unit of nucleic acids such as DNA.

4 Nitrogenous Bases in DNA

Adenine, guanine, cytosine, and thymine.

Purines and Pyrimidines

A biochemical compound consisting of a purine or pyrimidine base linked to a sugar. The bases are adenine, guanine, cytosine, and thymine.

Nitrogenous Base Pairing

A is always paired with T and C is always paired with G.

Antiparallel

The two strands of DNA run in opposite directions.

DNA Replication

The process by which DNA makes a copy of itself during cell division.

Semi-Conservative Replication

Method of DNA replication where one strand of each copy comes directly from the original molecule.

Leading Strand

The strand of DNA that is continuously synthesized during replication.

Lagging Strand

The strand of DNA that is synthesized in fragments during replication.

Okazaki Fragments

Short, newly synthesized DNA fragments that are formed on the lagging template strand during DNA replication.

DNA Helicase

An enzyme that unwinds the DNA double helix during replication.

DNA Polymerase

An enzyme that synthesizes new DNA strands during replication.

DNA Ligase

An enzyme that joins DNA fragments together during replication.

DNA Primase

An enzyme that synthesizes RNA primers during replication.

Polymerase Chain Reaction (PCR)

A technique used to amplify a single copy or a few copies of a segment of DNA across several orders of magnitude, generating thousands to millions of copies of a particular DNA sequence.

Gel Electrophoresis

The separation of nucleic acids or proteins, on the basis of their size and electrical charge, by measuring their rate of movement through an electrical field in a gel.

RNA

Single-stranded nucleic acid that contains the sugar ribose

Protein Synthesis

A vital biological process that synthesizes proteins from amino acids.

Transcription

The synthesis of RNA from a DNA template.

Translation

The synthesis of a protein from an mRNA template.

Codon

A sequence of three nucleotides that together form a unit of genetic code in a DNA or RNA molecule.

Anticodon

A sequence of three nucleotides forming a unit of genetic code in a transfer RNA molecule, corresponding to a complementary codon in messenger RNA.

mRNA

RNA that carries genetic information from DNA to the ribosome.

tRNA

RNA that carries amino acids to the ribosome for protein synthesis.

RNA Polymerase

Enzyme that synthesizes RNA from a DNA template during transcription.

Ribosome

An organelle where protein synthesis occurs.

Mutation

Any change in the nucleotide sequence of DNA.