bio exam review 2

diversifying selection (disruptive selection)

selection that favors two or more distinct phenotypes (up, down, up)

stabilizing selection

selection that favors average phenotypes (up, down)

directional selection

selection that favors phenotypes at one end of the spectrum or existing variation (opposite of beginning; if before is up, down then after is down, up)

spp

multiple species

pheromones

a communication chemical used within a species; intraspecific communication

sexual dimorphism

males and females different sizes

parasitoids

parasite that kills its host

ovipositor

egg laying "device" on creature

gall

leads to decrease in genetic diversity (stabilizing selection)

coevolution

organisms affecting each other's evolution (galling selects for specialized enemies)

symbiosis

any type of a close and long-term biological interaction between two different biological organisms

mutualism

++

commensalism

+0

parasitism

+-

drivers of diversification

environmental, genetic, organismal

genetic code

refers to the instructions contained in a gene that tell a cell how to make a specific protein; three letter codes that specify amino acid production (A-adenine, C-cytosine, G-guanine, T-thymine)

point mutation

a place where the A,C,G,T is changed/translated incorrectly

polypeptides

chain of amino acids

single nucleotide polymorphism

a germline substitution (type of mutation) of a single nucleotide at a specific position in the genome (>1% to be qualified polymorphism)

DNA damage

cellular metabolism, UV light exposure, ionizing radiation, chemical exposure, replication errors

DNA repair

direct reversal, base excision repair, nucleotide excision repair, mismatch repair, double strand break repair (homologous recombination or non-homologous end joining)

apoptosis

self-destruction of a cell; programmed cell death; plays a role in preventing cancer

UVA/UVB

found in lower atmosphere

UVC rays

filtered out in higher atmosphere

initiation

irreversible

promotion

reversible

order of cell things

complete repair, apoptosis, initiation, promotion, progression

new genes arise via mutation

deleterious, neutral, adaptive

deleterious

random changes in an evolved system, most common

neutral

a mutation that isn't good or bad

adaptive

a mutation that is helpful

multiniche polymorphism

some better at hunting, some better at foraging

Mendel

genetic breeding pea man

mendelian

recessive and dominant

Carl Correns, Hugo de Vries, Erich von Tschermak

found the same conclusions as Mendel

horizontal gene transfer

the sharing of genetic material between organisms that are not in a parent offspring relationship

transformation

the genetic alteration of a cell resulting from the direct uptake and incorporation of exogenous genetic material from its surrounding through the cell membrane

transduction

a mechanism of genetic recombination that occurs in bacteria where the incorporation of host cell DNA and the bacteriophage genetic material occurs, which results in the formation of recombinant DNA

conjugation

temporary union or permanent fusion as a form of sexual reproduction in certain algae and fungi

virus

a submicroscopic infectious agent that replicates only inside the living cells of an organism

phage (bacteriophage)

a virus that infects and replicates within bacteria and archaea; ubiquitous viruses (found wherever bacteria exist); infection begins by attachment of the phage particle to its host cell through specific recognition of a receptor on the host surface, followed by delivery of the phage nucleic acids into the infected cell, then it hijacks its cellular components and shuts down its defense mechanisms

prion

misfolded proteins that have the ability to transmit their misfolded shape onto normal variants of the same protein

microevolution

the theory that connects population change over time

macroevolution

big divergences in fossil record or geologic record, the process that gave rise to new species and higher taxonomic groups with wider divergent characters

Dawkins

famous evolutionary biologist

Pax 6 transcription factor

the eye gene

duplication events

genes getting two copies instead of one; biggest is entire genome mutation; most cases, second copy does nothing but sometimes it can have a new function via mutation: neofunctionalization

mutations are ultimate source of new genes

can occur during DNA replication; duplication mutations result from abnormal cell division either during mitosis or commonly during metaphase 1 in meiosis

polyploidy

whole genome duplication is now recognized as being present in almost all lineages of higher plants with multiple rounds of polyploidy occurring in more extant species

gametes

eggs and sperm

zygote

combination of two haploid cells (single cell, once split occurs, then embryo)

hemoglobin

has two parts that come from different chromosomes

epigenetics

the study of heritable phenotype changes that do not involve alteration in DNA sequence

allopatric speciation

physical barrier or something for dispersal

vicariance

the geographical separation of a population, typically by a physical barrier such as a mountain range or river, resulting in a pair of closely related species

dispersal

part of a population is moved from one place to far away; no longer connected to gene pool at original place

sympatric speciation

the evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic region; doesn't imply complete species isolation

maintaining reproductive isolation in sympatry

temporal isolation (prezygotic): time
habitat isolation: space
behavioral isolation: reproductive barriers
prezygotic isolation: gametic barriers
postzygotic barriers: hybrid sterility and zygote failure (mules)

prezygotic isolation

genetic barriers: eggs and sperm can't reach

postzygotic barriers

hybrid sterility and zygote failure

species

groups of interbreeding natural populations that are reproductively isolated from other such groups

epi

"on top of" or "in addition to" the traditional genetic basis for inheritance

gene expressions

the process of turning on a gene to produce RNA and protein

transcription

the process of making an RNA copy of a gene's DNA sequence

transcription factors

proteins involved in the process of converting or transcribing DNA into RNA; factors initiate and regulate the transcription of genes; signals from the environment or cells activate transcription factors; these bind to regulatory regions and determine transcription level

closed DNA

transcription cannot occur

open DNA

transcription factors bind and induce gene expression; environmental signals can open DNA to transcription

bacteria on organism chart

bacteria is further away and more diverse; archaea and eukaryota are closer

prokaryote reproduction

reproduce asexually by mitosis

eukaryote reproduction

many can reproduce asexually or sexually

parthenogenic

the production of clones as a result of asexual reproduction

mitosis

division of sematic cells; two daughter cells have the same number and kind of chromosomes as the parent cell

meiosis

haploid gamete; four daughter cells each have half the cells as the parent cell, as in the production of gametes

two fold cost of males

sexual females must spend 50% of the resources making sons which cannot themselves make offspring, the growth rate of sexual populations is predicted to be half that of the asexual population

HGT

genome diversification in prokaryotic species

plasmid

small double-stranded unit of DNA, usually circular but sometimes linear, exists independent of the chromosome and is capable of self replication; small circular molecule of double stranded DNA from larger plasmids that occur naturally in bacteria; transferred from cell to cell via conjugation

vertical transmission

plasmid transferred during replication to daughter cells

horizontal cells

plasmid transferring to bacteria of same generation

pilus

surface appendage of some prokaryotes used for attachment to surfaces including other prokaryotes

bacterial conjugation

the transfer of genetic material between bacterial cells by direct cell-to-cell contact or by a bridge-like contact or by a bridge-like connection between two cells

auxin

a plant hormone which causes the elongation of cells in shoots and is involved in regulating plant growth

cytokinins

promote cell division in roots and shoots

opines

used by bacteria for energy, carbon, and nitrogen

transfer of T-region

mediated by gene products encoded by the virulence genes located in the vir-region of Ti plasmid

relaxosome

the complex of proteins that facilitates plasmid transfer during bacterial conjugation

genes that code for relaxosome components

TraH: stabilizes the relaxosome's structural formation
TraI: enforces the relaxase protein
TraJ: recruits the complex to the oriT site
TraK: increases the "nicked" state of the target plasmid
TraY: imparts single-stranded DNA character on the oriT site
TraM: plays a particularly important role in relaxase interaction by stimulating "relaxed" DNA formation

genetic competence

the ability to undergo transformation

competent bacteria

possess highly specialized machines to transport DNA into their cytoplasm

horizontal gene transfer: transformation

for transformation to take place, the recipient bacteria must be in a state of competence, which might occur in nature as a time-limited response to environmental conditions such as starvation and cell density, and may also be induced in a lab

productive infections

when infection of a cell by a bacteriophage results in the production of new virions

lytic cycle

when virions are released by bursting the cell

lysogenic cycle

when a temperate bacteriophage infects a bacterial cell

prophage

when the phage DNA is incorporated into the host-cell genome

latency

when viruses can exist in nervous tissue for long periods of time without producing new virions, only to leave latency periodically and cause lesions in the skin where the virus replicates

horizontal gene transfer: transduction

1. phage invades donor bacterial cell
2. bacterial chromosome is broken down
3. transducing particles are assembled and the cell lyses
4. transducing particle invades new cell
5. donor DNA integrates into cell chromosomes

CRISPR

sequences derived from DNA from DNA fragments of bacteriophage; used to detect and destroy DNA from similar bacteriophages during subsequent infections; eliminates new phage material from being conjugated inside; molecular adaptive immune system of prokaryotes

totipotency

(of an immature or stem cell) capable of giving rise to any cell type or (of a blastomere) a complete embryo

Leeuwenhoek

17th century microscope maker/researcher

Brownian Motion

the erratic random movement of microscopic particles in a fluid as a result of continuous bombardment

molecular adhesion

cell surface proteins that mediate the interaction between cells; the amount charged particles can be stuck to others