Bio E1B Exam 2

Front 1

What are homologous structures?

Back 1

structures that are similar to each other b/c they are derived from a common ancestor

Example includes gills in human embryonic development

Front 2

Define orthologs

Back 2

Homologous genes in different species

Front 3

Define paralogs

Back 3

Two or more homologous genes within a single species

Front 4

Define torpor

Back 4

the process whereby an organism lowers its internal body temperature to just a few degrees above the environment

Front 5

Discuss leptin

Back 5

Hormone produced by adipose cells in proportion to fat mass, aka more fat = more leptin.

Leptin acts on the hypothalamus to reduce appetite and increase metabolic rate

Front 6

What purpose does brown adipose tissue serve?

Back 6

It allows for nonshivering thermogenesis that can increase the heat production in an animal

Front 7

Mosaic development

Back 7

Occurs when even if a blastomere is removed from a developing embryo, the remaining cells will go on to develop into a normal organism

Front 8

Directional selection

Back 8

a mode of natural selection in which a single phenotype is favored, causing the allele frequency to continuously shift in one direction. Under directional selection, the advantageous allele increase in frequency independently of its dominance relative to other alleles; that is, even if the advantageous allele is recessive, it will eventually become fixed.

Front 9

Disruptive selection

Back 9

Driving force behind sympatric speciation; describes changes in population genetics in which extreme values for a trait are favored over intermediate values

Front 10

Sympatric speciation

Back 10

the process through which new species evolve from a single ancestral species while inhabiting the same geographic region.

Front 11

Stabilizing selection

Back 11

a type of natural selection in which genetic diversity decreases as the population stabilizes on a particular trait value. This is probably the most common mechanism of action for natural selection.

Front 12

Autopolyploidy

Back 12

Multiple chromosome sets derived from a single species; can arise from spontaneous, naturally occurring genome doubling

Front 13

Allopatric speciation

Back 13

occurs when biological populations of the same species become isolated due to geographical changes such as mountain building or social changes such as emigration. The populations then undergo genotypic/phenotypic divergence. See Galapagos finches

Front 14

Parapatric speciation

Back 14

Occurs due to variations in the mating habits of a population within a continuous geographical area

Front 15

Interferon

Back 15

Glycoprotein made by lymphocytes in response to pathogens. Type of cytokine that interferes with viral replication w/in host cells

Front 16

Population bottleneck

Back 16

An evolutionary event in which a significant percentage of a population or species is killed or otherwise prevented from reproducing

Front 17

Extraembryonic membranes

Back 17

Structures that appear in parallel with the embryo but do not become part of the individual organism after birth such as the yolk sac, amnion or placenta

Front 18

Complement

Back 18

A group of 20+ blood proteins that cooperate with other defense mechanisms to enhance phagocytosis and also work with bound antibodies to lyse pathogens

Front 19

JGA

Back 19

Juxtaglomerular apparatus - specialized group of cells that forms between the DCT and the afferent arteriole of the associated glomerulus; release rennin in response to low BP or low osmolarity (Na+)

Front 20

Notochord

Back 20

Formed from the condensation of dorsal mesoderm and serving as a support in the embryos of all chordates; interacts with the overlying ectoderm to induce neural tube formation

Front 21

Acrosome

Back 21

Vesicle found at the tip of animal sperm; contains hydrolytic enzymes released as part of the acrosomal reaction to help penetrate the zona pellucida

Front 22

ACTH

Back 22

Adrenocorticotropic hormone - secreted by anterior pituitary and stimulates the production and secretion of steroid hormones of the adrenal cortex

Front 23

Archenteron

Back 23

Endoderm lined cavity formed during gastrulation - the primitive gut - that develops into the digestive tract

Front 24

Sexual selection

Back 24

Selection based on variation in secondary sex characteristics, leading to the enhancement of sexual dimorphism

Front 25

DAG

Back 25

Diacyl glycerol - product of phospholipase C; secondary messenger that binds to a stimulates the enzyme phosphokinase C - involved in Gastrin --> HCL secretion cascade

Front 26

MHC II

Back 26

Major histocompatibility complex class II - a large group of cell surface glycoproteins restricted to macrophages, B and some T cells; their role is to present antigens on the surface of an APC (macrophage or B cells) to T helper cells

Front 27

Chorion

Back 27

One of the extraembryonic membranes found in avian, reptilian and mammalian development; is responsible for exchange of gases and in mammals becomes part of the placenta

Front 28

Homeostasis

Back 28

The maintenance of a constant internal environment that results from regulatory system actions

Front 29

Animal vs. vegetal pole

Back 29

Animal pole differentiates into embryo forming the 3 primary germ layers and participating in gastrulation

Vegetal pole contains yolky cells and differentiates into extraembryonic membranes such as placenta

Front 30

Gene flows

Back 30

Refers to the transfer of alleles of genes from one population to another, often by the migration of a population

Front 31

Determination

Back 31

Refers to a cell’s commitment to eventually differentiate into a specific cell type and into no other tissue. Can only be defined experimentally and refers to the point where a cell is committed to a particular fate and can no longer regulate its differentiation into other cell types.

Front 32

Differentiation

Back 32

Describes the functional and structural changes associated with the expression of a developmental fate

Front 33

Cell fate

Back 33

Refers to the description of what a cell’s descendants will become if left unperturbed

Front 34

Epitope

Back 34

The small localized region on the surface of an antigen that is actually recognized by an antibody

Front 35

Vasa recta

Back 35

Capillary system that serves the loop of henle - blood flows countercurrent to flow of filtrate in the loop

Front 36

Phospholipase C

Back 36

Membrane bound enzyme activated by g proteins and activates secondary messenger cascade by IP3/DAG

Front 37

Batesian mimicry

Back 37

Convergence of phenotype of a nonpoisonous species with a poisonous one in which the mimic gains protection from predators that mistake it for the dangerous species

Front 38

Cortical granules

Back 38

Vesicles that are located under the egg plasma membrane and fuse with the membrane, releasing their contents, in response to increased cytosolic Ca2+ concentration as part of the slow block to polyspermy

Front 39

Directional selection

Back 39

Natural selection that favors individuals at one end of the phenotypic range

Front 40

Amnion

Back 40

One of the extraembryonic membranes that forms during the development of amniotes; encloses a fluid-filled sac in which the embryo is suspended

Front 41

Henson’s node

Back 41

Functional equivalent of the dorsal lip of the amphibian blastopore

Front 42

Neural crest cells

Back 42

Band of cells along the border where the neural tube pinches off from the ectoderm that migrate to various parts and form parts of the PNS as well as the bones of the skull and teeth; also form adrenal glands

Front 43

Podocytes

Back 43

Specialized cells that cover the fenestrated glomerular capillaries and have fine cytoplasmic extensions that form filtration slits

Front 44

Induction

Back 44

Series of signaling events whereby a cell or tissue signals to another cell or tissue to influence its developmental fate

Front 45

What is heterochrony?

Back 45

Changing the amount of time a particular gene is expressed in an embryo. An example is how the dolphin gets its flipper

Front 46

What is heterotopy?

Back 46

Changing the location of gene expression in an embryo. An example is the ribs migrating dorsally in a turtle via FGF10

Front 47

What is heterometry?

Back 47

Changing the amount of gene expression, aka mRNA expressed, in an embryo. BMP4 expression in Darwin’s finches determines the broadness of their beak and is an example of heterometry.

Front 48

What is heterotypy?

Back 48

Changing the type of gene expressed in an embryo

Front 49

Dendritic cell

Back 49

An APC that functions to initiate the immune response by presenting processed antigen on its MHC II proteins

Front 50

ZPA

Back 50

Zone of polarizing activity - a region of cells found at the posterior margin of the limb bud that produce and release the morphogen that establishes anterior-posterior polarity