Biology Ch. 3

Front 1

Virus

Back 1

-consists of a protein coat called a capsid, one to several hundred genes in the form of DNA or RNA
-some surround themselves with a lipid-rich envelope, either borrowed from the membrane of a host cell or synthesized in the host cell cytoplasm.
-tail, baseplate, and tail fibers are found in most bacteriophages.

Front 2

Capsid

Back 2

-a protein rich coat contained by viruses, contain either DNA or RNA

Front 3

Differences between viruses and living organisms

Back 3

1. always require a host cell's reproductive machinery to transfer genetic info
2. do not metabolize their own organic nutrients.
3. are not seperated from external environment by barrier such as a cell wall or membrane
4. Possess either DNA or RNA but never both.

Front 4

Bacteriophage

Back 4

-A virus that infects bacteria

Front 5

Methods by which viruses infect cells

Back 5

1. Inject nucleic acid through the tail after viral enzymes have digested a hole in the cell wall (typical for a bacteriophage)
2. engulfed by eukaryotes through an endocytotic process
-recognize a host through a chemical receptor that is a specific glycoprotein on the host cell membrane.

Front 6

Lytic cycle

Back 6

-the virus commandeers the infected cell's reproductive machinery and begins reproducing new viruses.
-the virus adsorbs to the cell wall, injects nucleic acids, the virus is replicated, then the cell bursts releasing the new viruses.

Front 7

latent period

Back 7

-period from infection to lysis during the lytic cycle of a virus

Front 8

virulent virus

Back 8

-a virus following the lytic cycle

Front 9

Lysogenic cycle or infection

Back 9

-the viral DNA is incorporated into the host genome, or, if the virus is an RNA virus it possesses the enzyme reverse transcriptase and DNA is reverse transcribed and incorperated into the host genome.
-when the host cell replicates its DNA, the viral DNA is incorporated as well.

Front 10

Temperate virus

Back 10

-A virus that is in the lysogenic cycle.

Front 11

Prokaryotes

Back 11

-have no membrane bound nucleus

Front 12

Archaea

Back 12

-Unlike bacteria, cell walls are not made from peptidoglycan

Front 13

Fixing CO2

Back 13

-the ability of microorganisms to reduce and use carbon from CO2 through a process called the Calvin cycle.

Front 14

Autotrophs

Back 14

Organisms capable of of using CO2 as their sole source of carbon

Front 15

Heterotrophs

Back 15

-Organisms that use preformed, organic molecules as their source of carbon

Front 16

phototrophs

Back 16

-organisms that use light as their energy source

Front 17

chemotrophs

Back 17

-organisms that use oxidation of organic or inorganic matter as an energy source

Front 18

Structure of prokaryotes

Back 18

-don't have a nucleus
-usually have a single, circular DNA
-DNA RNA and protein complex forms a structure called a nucleoid
-have no complex, membrane-bound organelles, but do have ribosomes
-may or may not have mesosomes (invaginations of the plasma membrane)
-have inclusion bodies (granules of organic or inorganic matter that may be visible under a light microscope.

Front 19

nucleoid

Back 19

-DNA, RNA and protein complex in prokaryotes that forms a visible structure
-not enclosed by a membrane

Front 20

cocci

Back 20

-round shape of bacteria

Front 21

bacilli

Back 21

rod shaped bacteria

Front 22

Spirilla

Back 22

helically shaped bacteria, very rigid

Front 23

Spirochetes

Back 23

-helically shaped bacteria, not as rigid as spirilla

Front 24

Plasma membrane

Back 24

-the cytosol of nearly all prokaryotes is surrounded by a phospholipid bilayer

Front 25

Phospholipid

Back 25

-Composed of a phoshphate group, two fatty acid chains, and a glycerol backbone.

Front 26

Micelle

Back 26

-An aggregate of amphipathic molecules in aqueous solution in which they turn their polar ends towards the solution and nonpolar ends toward each other.

Front 27

Integral or intrinsic proteins

Back 27

-Amphipathic proteins that traverse the membrane from inside of the cell to the outside

Front 28

Peripheral or extrinsic proteins

Back 28

-proteins that are situated entirely on the surface of the membrane.

Front 29

Fluid mosaic model

Back 29

-Since the forces holding the entire membrane together are intermolecular, the membrane is fluid; its parts can move laterally but cannot seperate

Front 30

Electrical gradient

Back 30

- For molecules with a charge, a gradient exists across a membrane that points in the direction that a positively charged particle tends to move.

Front 31

Electrochemical gradient

Back 31

-Electrical gradient and chemical gradient can combine to form this.

Front 32

Effects of size and polarity on a compound's permeability

Back 32

-The larger the size of the particle, the less permeable it is.
-The more polar, the less permeable.

Front 33

Passive diffusion

Back 33

-Molecules move through leakage channels across the membrane due to random motion.

Front 34

Transport or Carrier Proteins

Back 34

-proteins designed to facilitate the diffusion of specific molecules across the membrane

Front 35

Facilitated diffusion

Back 35

-In order to be called facilitated diffusion, diffusion must occur down the electro-chemical gradient of all species involved.
-selectively permeable

Front 36

Active transport

Back 36

-Movement of a compound up its electrochemical gradient.
-requires the expenditure of energy, either by direct expenditure of ATP or indirectly by using ATP to create an electrochemical gradient, and then using the energy of the electrochemical gradient to acquire or expel a molecule.

Front 37

Bacterial envelope

Back 37

-Surrounds the protoplast (which is the plasma membrane and everything inside). Includes the cell wall.
-the cell wall maintains hydrostatic pressure

Front 38

Peptidoglycan

Back 38

-A series of disaccharide polymer chains with amino acids.
-make up the cell wall of bacteria.

Front 39

Gram staining

Back 39

-A staining technique that stains two major cell walls differently.
-gram positive bacteria contain a thick peptidoglycan cell wall that prevents the gram stain from leaking out, thus the bacteria is dyed purple.
-gram negative bacteria appear pink when stained because they have a thin peptidoglycan cell wall that allows most of the stain to be washed off.
-have a phospholipid bilayer outside of the cell wall, polysaccharide chains that form a protective barrier from antibodies and many antibiotics.

Front 40

Bacterial flagella

Back 40

-long, hollow, rigid helical cylinders made from a globular protein called flagellin.
-don't confuse w/ eukaryotic flagella!

Front 41

Flagellin

Back 41

-a globular protein that makes up bacterial flagella

Front 42

Binary fission

Back 42

-cell division, asexual reproduction
-DNA replication process is similar to replication in eukaryotes
-the cell divides, leaving one circular chromosome in each daughter cell. the two daughter cells are genetically identical.

Front 43

3 forms of genetic recombination employed by bacteria

Back 43

1. conjugation
2. transformation
3. transduction

Front 44

Conjugation

Back 44

-Requires that a bacterium have a plasmid with gene that code for the sex pilus.
-passage of DNA is always from the cell containing the conjugative plasmid to the cell that does not.
-one strand is nicked and one end of this strand begins seperate from its complement as its replacement is replicated.

Front 45

F plasmid

Back 45

-the fertility factor of F factor
-the pilus is made while the F factor is incorporated into the chromosome

Front 46

Sex pilus

Back 46

-A pilus that grows from one bacteria to another in order to perform conjugation.
-requires the presence of an F plasmid.

Front 47

Transformation

Back 47

-A type of DNA recombination in bacteria
-The process by which bacteria may incorporate DNA from their external environment into their genome.

Front 48

Transduction

Back 48

-A type of DNA recombination in bacteria
-Sometimes, the capsid of a bacteriophage will mistakenly encapsulate a DNA fragment from a host cell.
-When these virons infect a new bacterium, they inject harmless bacterial DNA fragments instead of virulent DNA fragments.

Front 49

Endospores

Back 49

-resistant to UV radiation, chemical disinfection, dessication.

Front 50

Saprophytic

Back 50

-most fungi are saprophytic, meaning they live off of dead matter

Front 51

Septa

Back 51

-cell walls made of the polysaccharide chitin.
-make up fungi cell wall

Front 52

Chitin

Back 52

-a polysaccharide found in the fungal cell wall known as septa

Front 53

Characteristics of fungi

Back 53

-saprophytic
-cell walls are septa made of chitin
-secrete their digestive enzymes outside their bodies and then absorb the products of digestion.
-lack centrioles, mitosis takes place entirely within the nucleus
-typically haploid stage, but do alternate between diploid and haploid stages.
-can reproduce sexually or asexually

Front 54

Mycelium

Back 54

-During growth state, fungi consist of this tangled mess

Front 55

Hyphae

Back 55

-multiply branched thread-like structures found during the growth stage of fungi

Front 56

Fungal spore

Back 56

-haploid structures released by fungi that give rise to new mycelia in asexual reproduction.

Front 57

Budding (cell fission)

Back 57

-An asexual reproductive method utilizied by yeasts in which a smaller cell pinches of from a single parent cell.

Front 58

vaccine

Back 58

-can be either an injection of antibodies or an injection of a non-pathogenic virus with the same capsid or envelope

Front 59

Provirus

Back 59

-During a lysogenic infection, while the viral DNA remains incorporated in the host DNA, the virus is said to be dormant or latent and is called a provirus.

Front 60

Plus-strand RNA

Back 60

-indicates that the proteins in a virus can be directly translated from the RNA.

Front 61

Retroviruses

Back 61

-a virus which carries the enzyme for reverse transcriptase in order to create DNA from its RNA.
-the DNA is then incorporated into the

Front 62

Minus-strand RNA

Back 62

-Minus-strand RNA is the complement to mRNA and must be transcribed to plus-RNA before being translated.

Front 63

the 4 types of viruses

Back 63

1. plus-strand RNA
2. minus-strand RNA
3. Double stranded RNA viruses
4. Double stranded DNA viruses

Front 64

Vaccine

Back 64

-can either be an injection of antibodies or an injection of a non-pathogenic virus with the same capsid or envelope. The later allows the immune system to create its own antibodies.