IB Biology SL Vocabulary

Genotype

The combination of the alleles on an organism's genes expressed in letters

Phenotype

The expression in traits of a genotype, which is described in words rather than represented by letters.

Dominant Allele

The part of a genotype allele which overrides recessive genes, and is always expressed in the phenotype, and represented by a capital letter.

Recessive Allele

The part of the genotype which can be overrided and not expressed in the presence of a dominant allele, and only expressed in a homozygous recessive allele combination.

Co-dominant Allele

A special circumstance in which both parts of an allele are expressed in the phenotype.

Homozygous

When two parts of the allele are the same as each other (Both dominant or both recessive).

Test-Cross

A test used to determine genotype of an unknown parent crossed with a homozygous recessive parent.

Punnet Square

A tool used to find the potential outcomes of a cross.

Pedigree Chart

A tool used to track a specific trait throughout the history of a particular organism.

Sex Linkage

Describes that a trait is carried through a particular sex, such as through mothers or through the fathers

Polymerase Chain Reaction

A process used to amplify small samples of DNA to use for genetic profiling, research and recombination

Gel Electrophoresis

A form of DNA Profiling which uses electrophoresis gel to put samples of amplified DNA into to produce a genetic profile.

DNA Profiling

A process which compares sections of DNA to determine patterns or paternity

Plasmid

Circles of DNA found in bacteria

Restriction Enzyme/ endonucleases

An enzyme required in gene transfer which cuts the any desired gene from the genome to be replaced.

Transgenic

An organism made by inserting a gene into an embryo so that it will develop the trait for that gene

Species

A classification unit in biology which describes a set of organisms which can reproduce together producing fertile offspring.

Habitat

The physical environment in which an organism lives.

Population

Population refers to the collective group of a particular species living in the same environment at the same time.

Community

A group of populations which live in the same environment at the same time and interact with each other.

Ecosystem

made up of the communities and the physical environment.

Autotroph

Any organism which can produce its own food out of organic molecules, like Carbon Dioxide.

Heterotroph

Any organisms which derive energy from other living organisms.

Consumers

Organisms which get their energy by eating other living organisms, or recently killed organisms.

Detritivores

Heterotrophs which derive energy by eating non-living organic matter.

Saprotrophs

Organisms which live in non-living organic matter and derive energy from it by secreting enzymes into it.

Trophic Level

Trophic levels represent the feeding status of organisms in a food chain or web.

Carbon Cycle

The natural/artificial processes through which carbon is exchanged through the earth and recycled and reused.

Keeling Curve

The curve developed over 40 years since 1960 by Charles Keeling which shows the significant increase in Carbon Dioxide levels in the earth's atmosphere since 1960.

Greenhouse Effect

The naturally occurring process of the greenhouse gases, carbon dioxide, nitrous oxide, methane, and water vapor, being trapped into the troposphere, raising temperatures on earth.

Precautionary Principle

The principle developed by environmentalists that corporations or operations should have to prove that their project will not harm the environment before they start.

Natality

The rate of birth in a population.

Sigmoid Shaped Population Curve

The graph of population increase which demonstrates how populations increase exponentially, gradually slowing as competition increases, then eventually plateau as the competition evens out the population.

Exponential Growth

A phase of the sigmoid shaped population curve which shows the initial rapid increase in population as members of a species produce more offspring than the environment can support.

Transitional Phase

Phase on the sigmoid shaped population curve in which the scarcity of resources causes a slow in population increase.

Plateau

The point on the sigmoid shaped population curve in which the population stops increasing and levels out as competition eliminates the rapid growth, and the population of the population reaches it's carrying capacity (K)

Evolution

The small changes over generations in the heritable traits of a population

Natural Selection

The process of a species preserving and passing down helpful traits and rejecting unhelpful traits.

Artificial Selection

The process of humans interfering by choosing to breed those organisms which display the traits we want.

Homologous Structure

Structures in various species designed for a specific task which are very similar. Provides evidence for Evolution.

Natural Variance

The variation in genes which occurs naturally from the random alignment or combination of chromosomes.

Adaptive Behavior

A behavior change carried out in response to environmental change which helps thr organism survive the change.

Mutation

Accidental changes in DNA sequence sometimes caused by a virus.

Sexual Reproduction

The combining of the genetic material of two organisms within a species to produce offspring.

Resistance

The gradual development of genes which enable organisms to resist an environmental change that could kill off the species.

Adaptation

A trait which serves a use to the organism and is passed on through natural selection.

Binomial Nomenclature

A two-part naming system for organisms which uses the capitalized genus name followed by the uncapitalized species name in order to identify a specific organism.

Taxa

The individual levels of classification for organisms

Kingdom

Phylum

Class

Order

Family

Genus

Species

Dichotomous Key

A series of binary questions which can be used to identify an organism based on physical characteristics.

Hiearchy

Refers to the classification of organisms in the various ranks, which descend down in specificity.

Bryophyta

A group of plants which are very simple and have no roots or stem, and small leaves and a furry appearance.

Filicinophyta

A group of plants with roots, leaves, and short stems. They have no lignin, and leaves are divided up into small sections and are often curled.

Coniferophyta

A group of plants with lignin in their trunks, and have pine needles for leaves.

Angiospermophyta

A group of plants with roots, stems, and leaves, which produce flowers.

Porifera

A phylum of the kingdom Animalia, which is characterized by no symmetry, no mouth or anus, no segmentation, and are porous filter feeders. (sponges)

Cnidaria

A phylum of the kingdom Animalia which is characterized by radial symmetry, a mouth but no anus, no segmentation, and stinging tentacles surrounding the mouth.(jellyfish)

Platyhelminthes

A phylum of the kingdom Animalia which is characterized by bilateral symmetry, a mouth but no anus, no segmentation, and a ribbon shaped body. (worms)

Annelida

A phylum of the kingdom Animalia which is characterized by bilateral symmetry, a mouth and an anus, very segmented bodies, and possibly with bristles and visible blood vessels. (earthworms)

Mollusca

A phylum of the kingdom Animalia which is characterized by bilateral symmetry at the foot, but no symmetry in the shell, a mouth and anus, but no visible segmentation. Often have shells but not always. (octupus, squid)

Arthropoda

A phylum of the kingdom Animalia which is characterized by bilateral symmetry, a mouth and anus, with segmentation and joints. They also have an exoskeleton, and jointed appendages. (crabs)

Digestion

The breakdown of food and macromolecules using enzymes to make it able to absorbed by the body.

Ingestion

The process of taking in macromolecules as food to be digested

Egestion

Getting rid of any substances which cannot be absorbed by the digestive system, such as fibers and dead cells.

Absorption

Absorption is the process of the food which has been broken down into monomers entering the body through the villi into the blood stream.

Assimilation

The process of the absorbed monomers being transported and used by the cells for cellular processes and energy.

Amylase

An human digestive enzyme found in the salivary glands which breaks down carbohydrate macromolecules and has starch as a substrate, and produces maltose

Protease

A human digestive enzyme located in the duodenum section of the small intestine which breaks down the protein macromolecules with polypeptides as a substrate, and amino acids as a product. It has a pH of around 8. (slightly basic)

Lipase

A human digestive enzyme found in the pancreas which breaks down lipids or fats to create fatty acids and glycerol. Its substrate are tryglycerides, and it has a neutral pH. (7)

Villus

Small finger-like structures surrounding the inner surface of the small intestine which serve to increase the surface area for absorbing monomers through the lacteal and capillaries

Atrium

Areas of the structure of the heart from which the blood is pumped through and from. Divided into the right atrium and the left atrium (On the top, switched sides) (the one on the right is the left atrium)

Ventricle

Structures within the heart which have thick muscle lining to pump the blood into the arteries at a high pressure.

Aorta

A tube which sends blood out of the heart to the body.

Superior/Inferior Vena Cava

A tube which transports blood from the body into the heart. This is where the blood circulation begins.

Valves (Aortic, Mitral, Pulmonary, Tricuspid)

Small structures between the various areas of the heart which prevent the backflow of blood, and push blood forward through the stages of circulation within the heart.

Artery/ arteriole

Tubes that carry blood with nutrients and oxygen away from the heart

Vein/ venule

Tubular structures within the heart which carry deoxygenated blood back into the heart.

Capillary

The smallest tubes of the heart which carry low-pressure blood, have no valves, or muscle tissue, and are only one cell thick to allow for easy diffusion.

Myogenic Muscle Contraction

The contraction within the heart originating from individual muscle cells, not externally.

Sinoatrial node/ pacemaker

A group of muscle cells which set the rate at which the heart contracts or beats.

Atrioventricular node

The node to which the sinoatrial node sends it's impulses, and from the atrioventricular node the impulse is carried to the veins and arteries telling them to contract.

Plasma

One of the components of blood which is made up of mostly water and dissolves or carries nutrients, wastes, and other parts that make up the blood.

Erythrocytes

Cells in blood which transport hemoglobin molecules. (Red Blood cells)

Leucocytes: Phagocytes and Lymphocytes

A type of cell in blood which is divided into two types. Phagocytes are a type of leucocyte which 'eat' harmful pathogens and dead cells away from the blood. Lymphocytes are a type of leucocyte which are divided into B-cells and T-cells and are responsible for the body's immunity.

Platelets

A component of blood which clots the blood flow in order to recover from an injury to the cells.

Pathogen

A microorganism which causes disease in animals, plants, and humans.

Antibiotic

Any substance which stunts the growth of or kills bacteria by blocking specific metabolic pathways

Mucous Membrane

A physical barrier on humans which protects from pathogens in the nose and mouth

Phagocytic Leucocytes

A specific type of leucocyte or white blood cell which defends the body from pathogens by eating or engulfing foreign objects via phagocytosis.

Antigen

A substance found on viruses which triggers the production of antibodies by alerting the body's immune response to the foreign object.

B Lymphocyte: Memory cell

A type of leucocyte whose main role is to produce antibodies for specific antigens. Also called memory cells because they remember the specific antibody needed for each antigen.

HIV

A retrovirus which weakens the immune system by inputting it's RNA and causing the cell to reproduce that DNA.

AIDS

An immune deficiency disease cause by the HIV virus and abbreviated for acquired immune deficiency syndrome.

Ventilation

Moving of the air in and out of lungs, called inhalation and expiration, and controlled by the ribcage and diaphragm.

Gas Exchange

Gas exchange is the process of oxygen entering the blood and carbon dioxide leaving by diffusing through the blood vessels surrounding the alveoli.

Alveoli

Millions of small structures with thin moist membranes on the end of the bronchioles in lungs which increase the surface are, maximizing gas exchange, and surrounded by blood vessels to diffuse oxygen and carbon dioxide in and out of the blood.

Trachea

Tube that goes from the mouth and nose to the lungs transporting air into the lungs.

Lungs

Organs in the human body containing bronchi, bronchioles, and alveoli in order to carry out gas exchange, to distribute oxygen to the body.

Bronchi

The two thick branch-like tubes which direct air coming from the trachea to each lung.

Bronchioles

Small tubes which branch off of the bronchi to distribute air to the entire lung. Bronchioles are surrounded by alveoli to maximize surface area and perform gas exchange.

External/Internal Intercostal Muscles

Muscles surrounding the ribcage which control its movement during ventilation.