Biology Definitions (Leaving Cert)

Biology

Is the study of living things.

The scientific method

is the process of investigation in which problems are identified and their suggested solutions are tested by carrying out experiments.

An observation

Is when something is noticed.

A hypothesis

Is an educated guess.

An experiment

Is designed to test a hypothesis.

Data

Consists of the MEASUREMENTS, OBSERVATIONS or INFORMATION GATHERED from experiments.

A conclusion

Is a summary of the results of an experiment.

A theory

Is a hypothesis that has been SUPPORTED by many different experiments.

A principle or law

Arises from a theory that has been shown to be VALID when FULLY TESTED over a long period of time.

A variable

Is a factor that may change in an experiment.

A control

is used to provide a comparison against which the actual experiment is being tested.

A replicate

Is a repeat of an experiment, under the same conditions.

Double blind

Means that both the investigator and the participant are unaware of the nature of the treatment the participant is receiving.

Ethics

Relates to whether conduct is right or wrong.

An Organism

Is a living thing.

Metabolism

Is the sum of all chemical reactions in an organism.

Continuity of life

Means that living things arise from other living things of the same type.

Life

Is defined as the possession of these five characteristics: organisation, nutrition, excretion, response, reproduction.

Organisation

Means that living things are composed of cells, tissues, organs, and organ systems.

Nutrition

Is the way living things get and use food FOR ENERGY.

Exrection

Is the removal of waste products of METABOLISM.

Response

is the way living things REACT to changes in their environment.

Reproduction

Is the production of new individuals.

Sexual Reproduction

Involves the union of sex cells.

Asexual Reproduction

Dose not involve the union of sex cells.

Biomolecules

Are the chemicals that are made inside a living thing.

Phospholipids

Are fat-like substances in which one of the fatty acids is replaced by a phosphate group or has a phosphate group added to it.

Anabolic reactions

The USE energy to convert smaller molecules into larger molecules.

Catabolic reactions

The RELEASE energy when a complex molecule is broken down to a simpler form.

Cytoplasm

Is the living material in a cell outside the nucleus.

Transmission Electron Microscope

Shows the internal structure of a specimen.

Scanning Electron Microscope

Shows a surface view of a specimen.

Cell ultra-structure

Is the fine detail of a cell as seen with an electron microscope.

Chromatin

Is the name given to chromosomes when they are elongated and not dividing.

Hydrophilic

Water loving.

Hydrophobic

Water hating.

Prokaryotic cells

Do not have a nucleus or membrane bound organelles. e.g. bacteria cells.

Eukaryotic cells

Have a Nucleus and membrane bound organelles. e.g. animal and plant cells.

Tissue

Are groups of similar cells that have the same structure and function.

Micropropogation

Is the growth of new plants from plant cells.

Callus

A group of cells.

Tissue culture

Is the growth of new cells in or on a sterile nutrient medium outside the organism.

Monoclonal antibodies

Cancer treatment antibodies.

In vitro

Outside of the body.

Organ

Is a structure composed of a number of different tissues that work together to carry out one or more functions.

Organ system

Consists of a number of Organs working together to carry out one or more functions.

Organism

A group of organ systems working together to allow life.

Diffusion

Is the spreading of gas molecules from a region of high concentration to a region of low concentration. (Passive Process)

Osmosis

Is the movement of water molecules from a region of high water concentration to a region of low water concentration across a selectively permeable membrane. (Passive Process)

A selectively permeable membrane

Allows some but not all molecules through.

Hypertonic

Water concentration is higher inside than outside the cell.

Isotonic

Water concentration is the same inside and outside the cell.

Hypotonic

Water concentration is higher outside the cell than inside the cell.

Protoplasm

Is all the living parts of a cell.

Turgor or Turgor pressure

Is the OUTWARD pressure of the cytoplasm and vacuole AGAINST the cell wall of the plant.

Cell continuity

Means that cells develop from pre-existing cells.

Chromosomes

Are COILED THREADS of DNA and protein.

A gene

Is a section of DNA that contains the instructions to make a protein.

A diploid Cell

Has two sets of chromosomes, one from the mother and one from the father. (2n)

A homologous Pair

is two chromosomes of similar size, with the same sequence of genes.

Haploid cells

Have one set of chromosomes. (n)

Interphase

Is the phase in the cell cycle when the cell is not dividing.

A centromere

Is the point where chromosomes attach.

Mitosis

Is a form of nuclear division in which one nucleus divides into two nuclei, each containing identical sets of chromosomes.

Cancer

Is a group of disorders in which certain cells lose their ability to control both the rate of mitosis and the number of times it happens.

Meosis

Is the form of nuclear division in which 4 daughter nuclei contain half the number of parent chromosomes.

Micro-organisms

Are small living things.

Autotrophic

Means an organism makes its own food.

Chemosynthesis

Is the production of food using energy released from chemical reactions.

Photosynthetic

Describes bacteria that make their own food using light energy.

Heterotrophic

Means an organism takes in food made by other organisms.

Saprophytes

Are organisms that take in food from dead organic matter.

Parasites

Are organisms that take in food from a live host and usually cause harm.

Pathogenic Bacteria

Are bacteria that cause disease.

Antibiotics

Are chemicals produced by micro-organisms that stop the growth of, or kill other micro-organisms without damaging human tissue.

Batch Culture

Is the cell growth of cells in a sealed container, or bioreactor, over a short period of time under ideal conditions until all the nutrients are used up.

A Bioreactor

Is a vessel or container in which living cells or their products are used to make a product.

Continuous Flow

Food processing is the growth of cells in an open container, or bioreactor, where nutrients are added and the end products are removed all the time at a rate that maintains the volume of liquid and the number of cells.

Aerobic Bacteria

Use oxygen

Anaerobic Bacteria

Do not use oxygen

Hypha

Is a tube or filament in a fungus.

Mycelium

Is a visible mass of hyphae.

Obligate parasite

Can only take it's food from a live host.

Facultative parasite

Can get its food from a live or dead host.

Sporulation

Is the process of making spores.

Meristem

Is a plant tissue capable of mitosis.

Herbaceous plants

do not contain wood (lignin)

Woody plants

contain wood (lignin)

Node

Is the point of a stem at which the leaf is attached

internode

is the region on a stem between two nodes

bud

is a potential growth point which may develop into a shoot, a leaf or flower

lenticel

is an opening on a stem for gas exchange

venation

is the pattern of veins in a leaf

Lignin

is a strengthening material found in some plant cell walls

cotyledon

is a seed leaf

Plasma

Is the liquid part of the blood

Serum

Is plasma with the blood clotting proteins removed.

Erythrocytes

Red blood cells

Lymphocytes

White blood cells that produce antibodies

Monocytes

White blood cells that engulf pathogens.