Openstax-Microbiology Chapter 3 The Cell

spontaneous generation

Hypothesis stating that life could arise from nonliving matter.

Endosymbiotic theory

theory that eukaryotic cells formed from a symbiosis among several different prokaryotic organisms

Germ Theory of disease

the principle that microorganisms cause disease

Ribosomes

organelles made of protein and RNA that direct protein synthesis in the cytoplasm

Prokaryotic cells

cells without a nucleus or other membrane-bound organelles

Eukaryotic cells

Larger, complex, with nucleus, membrane bound organelles, DNA tightly wrapped around histone proteins in chromosomes, cellulose in plant cell walls.

cell morphology

Study of cell shape and size.

Cell wall

A rigid layer of nonliving material that surrounds the cells of plants and some other organisms.

osmotic pressure

pressure that must be applied to prevent osmotic movement across a selectively permeable membrane

osmosis

Diffusion of water through a selectively permeable membrane

isotonic medium

The solute concentrations inside and outside the cell are approximately equal, so there is no net movement of water across the cell membrane

hypertonic medium

the solute concentration outside the cell exceeds that inside the cell, so water diffuses out of the cell and into the external medium

hypotonic medium

The solute concentration inside the cell exceeds that outside of the cell, so water will move by osmosis into the cell. This causes the cell to swell and potentially lyse, or burst

crenation

This happens when a cell shrinks and shrivels; can result in cell death if severe.

plasmolysis

Collapse of a walled cell's cytoplasm due to a lack of water

nucleoid

A dense region of DNA in a prokaryotic cell.

nucleoid-associated proteins (NAPs)

a set of DNA-binding proteins found in bacteria that facilitate chromosome compaction and organization

pasmid

a genetic structure that can replicate independently of the main chromosomes of a cell; a circular DNA molecule in bacteria

70s ribosomes

smaller ribosomes found in prokaryotes

inclusions

Chemical substances such as stored nutrients or cell products

Volutin granules/ metachromatic granules

The type of inclusion containing polymerized inorganic phosphate is called______________.

Polyhydroxybutyrate (PHB)

an inclusion that displays a phospholipid monolayer embedded with protein surrounding inclusions

magnetosomes

inclusions of iron oxide surrounded by invaginations of the plasma membrane

carboxysome inclusion

composed of outer shells of thousands of protein subunits

vegetative cells

metabolically active cells

endospores

structures produced by bacteria and formed to cope with harsh environmental conditions

sporulation

formation of endospores

germination

Early growth stage of a plant embryo

cell envelope

In a prokaryotic cell, the portion composed of the plasma membrane, the cell wall, and the glycocalyx.

plasma membrane

A selectively-permeable phospholipid bilayer forming the boundary of the cells

fluid mosaic model

model that describes the arrangement and movement of the molecules that make up a cell membrane

chlorophylls

green pigment required for photosynthesis that traps the radiant energy of sunlight

peptidoglycan

A protein-carbohydrate compound that makes the cell walls of bacteria rigid

mycolic acid

long-chained, branched fatty acids characteristic of members of the genus mycobacterium

periplasmic space

The space between the inner and outer cell membranes in Gram-negative bactera. The peptidoglycan cell wall is found in the periplasmic space, and this space sometimes contains enzymes to degrade antibiotics.

outer membrane

The outer membrane is the outermost membrane in the mitochondria that protects and holds the form of the organelle.

Lipopolysaccharide (LPS)

Molecule that makes up the outer layer of the outer membrane of Gram-negative bacteria

glycocalyx

The external surface of a plasma membrane that is important for cell-to-cell communication

capsule

A sticky layer that surrounds the cell walls of some bacteria, protecting the cell surface and sometimes helping to glue the cell to surfaces.

slime layer

loose, water-soluble glycocalyx

s-layer

an outermost cell surface layer composed of protein or glycoprotein present on some Bacteria and Archaea

fimbriae

finger or fringe like projections at the end of the fallopian tubes

pili

Appendages that allow bacteria to attach to each other and to transfer DNA

F pilus (sex pilus)

a protein appendage required for DNA transfer in the process of conjugation

Flagella

whiplike tails found in one-celled organisms to aid in movement

monotrichous

single flagellum

amphitrichous

flagella at both poles of the cell

lophotrichous

cluster of flagella at one or both ends

peritrichous

flagella distributed over the entire cell

phototaxis

movement in response to light

magnetotaxis

movement toward or away from the Earth's magnetic field

chemotaxis

Cell movement that occurs in response to chemical stimulus

runs and tumbles

What are the types of movement allowed by flagella

cytoskeleton

A network of fibers that holds the cell together, helps the cell to keep its shape, and aids in movement

nucleus

A part of the cell containing DNA and RNA and responsible for growth and reproduction

coenocytes

multinucleate cells resulting from repeated mitoses but postponed or no cytokinesis.

nuclear membrane

A highly-porous membrane that separates the nucleus from the cytoplasm

nuclear lamina

A netlike array of protein filaments lining the inner surface of the nuclear envelope; it helps maintain the shape of the nucleus.

nucleolus

a dense region where tiny organelles essential for making proteins are assembled

80S ribosomes

larger ribosomes found in eukaryotes

free ribosomes

ribosomes suspended in the cytosol

membrane bound ribosomes

(forming rough ER) synthesize proteins to be incorporated into membranes, lysosomes, or exported from cell

endomembrane system

A network of membranes inside and around a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles.

Endoplasmic Reticulum (ER)

An extensive membranous network in eukaryotic cells, continuous with the outer nuclear membrane and composed of ribosome-studded (rough) and ribosome-free (smooth) regions.

cisternae

Flattened, membrane-bound compartments that make up the Golgi apparatus.

Rough Endoplasmic Reticulum (RER)

the region of the endoplasmic reticulum that is studded with ribosomes and engages in protein modification

Smooth Endoplasmic Reticulum (SER)

the region of the endoplasmic reticulum that has few or no ribosomes on its cytoplasmic surface and synthesizes carbohydrates, lipids, and steroid hormones; detoxifies chemicals like pesticides, preservatives, medications, and environmental pollutants, and stores calcium ions

transport vescicles

A tiny membranous sphere in a cell's cytoplasm carrying molecules produced by the cell. The vesicle buds from the ER or Golgi apparatus and eventually fuses with another organelle or the plasma membrane, releasing its contents

Golgi apparatus

A system of membranes that modifies and packages proteins for export by the cell

lumen

space within a tubular part or organ, such as the space within a blood vessel

secretory vescicles

spherical membranous sacs

Lysosomes

An organelle containing digestive enzymes

peroxisomes

membranous sacs containing enzymes used to break down hydrogen peroxide

microfilaments and microtubules

support the cytoplasm and help move substances and organelles within the cytoplasm

actin

A globular protein that links into chains, two of which twist helically about each other, forming microfilaments in muscle and other contractile elements in cells.

pseudopodia

A cellular extension of amoeboid cells used in moving and feeding.

centrosomes

Microtubule-organizing centers that help to form and organize the mitotic spindle during mitosis

centrioles

Cell organelle that aids in cell division in animal cells only

mitochondria

An organelle found in large numbers in most cells, in which the biochemical processes of respiration and energy production occur.

mitochondrial matrix

The compartment of the mitochondrion enclosed by the inner membrane and containing enzymes and substrates for the Krebs cycle.

chloroplasts

organelles that capture the energy from sunlight and convert it into chemical energy in a process called photosynthesis

stroma

fluid portion of the chloroplast; outside of the thylakoids

thylakoid

A flattened membrane sac inside the chloroplast, used to convert light energy into chemical energy.

Endocytosis

process by which a cell takes material into the cell by infolding of the cell membrane

phagocytosis

A type of endocytosis in which a cell engulfs large particles or whole cells

pinocytosis

A type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes.

receptor-mediated endocytosis

The movement of specific molecules into a cell by the inward budding of membranous vesicles containing proteins with receptor sites specific to the molecules being taken in; enables a cell to acquire bulk quantities of specific substances.

Excocytosis

process of exporting proteins from a cell by a vesicle fusing with the cell membrane

ectracellular matrix

the space between adjacent cells

flagella

whiplike tails found in one-celled organisms to aid in movement

dynein

A large contractile protein forming the side-arms of microtubule doublets in cilia and flagella.

Cilia

Hairlike projections that extend from the plasma membrane and are used for locomotion

basal body

organelle that develops from a centriole