EMES 204 Ch. 1

microorganisms

life forms too small to be seen by the unaided human eye

microbial communities

Microorganisms exist in nature in populations of interacting assemblages

pathogens

microbes that cause disease

microbial culture

collection of cells that have been grown in or on a nutrient medium

growth

increase in cell size, increase in the number of cells as a result of cell division

cytoplasmic membrane

A phospholipid bilayer embedded with proteins that surrounds the cytoplasm and defines the boundary of the cell

macromolecules

carbohydrates, lipids, proteins, nucleic acids

ribosomes

the structures responsible for protein synthesis

prokaryotic

cells that do not have a nucleus

eukaryotic

A cell characterized by the presence of a nucleus and other membrane-bound organelles. Eukaryotes can be unicellular (protists) or multicellular (fungi, plants and animals).

three domains of life

Bacteria, Archaea, Eukarya

genome

the full set of genes in a cell; living blueprint of an organism; the characteristics, activities, and very survival are governed by this

chromosomes

the genomes of prokaryotic cells and eukaryotic cells are organized into these structures

nucleoid

A dense region of DNA in a prokaryotic cell.

plasmids

small circular DNA molecules that replicate separately from the bacterial chromosome

metabolism

process through which nutrients are acquired from the environment and transformed into new cellular materials and waste products

enzymes

proteins that have catalytic activity and carry out reactions that supply energy and perform biosynthesis within the cell

transcription

the process by which the information encoded in DNA sequences is copies into an RNA molecule

translation

the process whereby the information in an RNA molecule is used by a ribosome to synthesize a protein

DNA replication

the process of making a copy of DNA

motility

ability to move; allows cells to relocate in response to environmental conditions

differentiation

process in which cells become specialized in structure and function

intercellular communication

interactions between cells using chemical signals

evolution

results when genes in a population of cells change in sequence and frequency over time, leading to descent with modification

morphology

defined by cell size and shape

micrometer

micron; millionth of a meter

cyanobacteria

Photosynthetic, oxygen-producing bacteria (formerly known as blue-green algae).

extremophiles

microorganisms that live in extreme environments.

chemolithotrophy

a form of metabolism in which energy is generated from the oxidation of inorganic compounds

rRNA

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

anabolism

Metabolic pathways that construct molecules, requiring energy.

catabolism

Metabolic pathways that break down molecules, releasing energy.

homeostasis

A tendency to maintain a balanced or constant internal state; the regulation of any aspect of body chemistry, such as blood glucose, around a particular level

biological carbon pump

process by which inorganic carbon is fixed by photosynthetic species that then die and fall to the sea floor where they cannot be reached by saprobes and their carbon dioxide consumption cannot be returned to the atmosphere

What do you need to know to calculate the total number of bacterial cells in the ocean?

You need to know both the number of bacterial cells per liter (~10⁹) and the total volume of the ocean in liters (~10²¹), then multiply the two values to arrive at approximately 10³⁰ total bacterial cells.