Biology 2601L: Quiz 2

bacteria

prokaryotes

prokaryotes

simplest living organisms

characteristics of prokaryotes

no membrane bound nucleus

DNA is not associated with proteins (to form chromosomes)

folded plasma membrane

lack membrane bound organelles

mitochondria and chloroplast are circular and organized into nucleoids

nucleoid

bacteria DNA concentrated in a mass

endosymbiosis

An association of two organisms in which one lives inside the other

3 shapes of bacteria

bacillus (rod-shaped), coccus (spherical), and spirillum (spiral)

pathogens

agents of disease

staphylo

cluster

coccus

the way an organism grows

strepto

bent or twisted

cyanobacteria

photosynthetic bacteria

unicellular

consisting of one cell

colony

group of cells

filaments

cells arranged in a linear fashion

heterocysts

thick-walled cells in which nitrogen fixation takes place

Antibacterials

substances that inhibit or prevent the growth of bacteria

Antibiotics

antibacterial substances produced by living organisms

what is the cause of disease?

the presence of bacteria or of toxins the bacteria produce

antibacterials target all

prokaryotic cells

What does growing bacteria look like on a petri dish?

Small, round colonies that look somewhat slimy.

Colors can be white, off-white, or yellow.

What does growing fungi look like on a petri dish?

hairy or fuzzy spots (could be spores) that appear as a dark, powdery substance

spore

dormant cells that each can form a new colony

what does a petri dish contain?

nutrients that support the growth of certain microorganisms

microvilli

folds in the plasma membrane

Gel electrophoresis

a method that separates macromolecules, such as nucleic acids and proteins, in which molecules are forced across a span of gel, motivated by an electrical current

Gel

a colloid in a solid form

colloid

a substance that consists of particles dispersed throughout another substance which are too small for resolution with an ordinary light microscope but are incapable of passing through a semipermeable membrane

agarose

a natural colloid extracted from seaweed

agarose gel

very fragile and is easily destroyed by handling; has a very large pore size and is primarily used to separate very large molecules; can be processed quickly, however, resolution suffers

electrophoresis

a term that describes the migration of charged particles under the influence of an electric field

electro-

energy of electricity

phoresis-

greek verb meaning to “carry across”

Charge of DNA

negative

important biological molecules that can be run across the gel

amino acids, peptides, proteins, nucleotides, and nucleic acids

separation of large molecules depends on which two forces?

charge and mass

restriction enzyme

reads and cut DNA upon recognizing the unique sequence

restriction fragments

DNA fragments that was cut by restriction enzymes

gene

a segment of DNA in a chromosome that encodes for RNA or protein

alleles

alternate forms of a single gene

genotype

the genetic makeup of an individual; the genetic combination of alleles

phenotype

the physical or chemical expression of an organism’s genes

homozygous

possessing a pair of identical alleles for a particular locus/trait

heterozygous

possessing a pair of unlike alleles for a particular locus/trait

dominant allele

an allele whose phenotype is expressed in a heterozygote

recessive allele

an allele whose phenotype is not expressed in a heterozygote

monohybrid cross

a genetic cross that takes into account the behavior of alleles of a single locus

parental generation

one parent is homozygous dominant and the other parent is homozygous recessive

F₁ generation

after crossing parents, the generation is heterozygous

F₂ generation

varied phenotypes and genotypes

macroevolution

the process by which new species emerge from existing species

microevolution

the change of allelic frequency of a population

The Hardy Weingberg Equilibrium

Meeting all these conditions prevent microevolution

1. The population is very large (no genetic drift)

2. Matings are random (no assortative mating)

3. There are no net changes in the gene pool due to mutation.

4. There is no migration of individuals into and out of the population (no gene flow)

5. There is no selection (no natural selection)

founder effect

the change in allelic frequency of a population that results from separation from a larger original population

genetic drift

the random change in allele frequencies of a population through time; stronger in smaller populations

natural selection

the process that eliminates individuals wiht low fitness and selects individuals with high fitness to survive and pass on their advantageous traits to the next generation.

Hardy-Weinberg Theorem Conditions:

1. The population is very, very large.

2. Matings are random.

3. There are no net changes in the gene pool due to mutation

4. There is no migration.

5. There is no selection.

founder effect

a form of genetic drift occurring when a small group of individuals establishes a new population, resulting in reduced genetic variability

genetic drift

a random change in allele frequencies through time

frequency of B allele

(2(BB) + BR) / total # of alleles