Bio 1A Section 3 Flashcards

ligand

signaling molecule

receptor protein

ligand binds to this (usually membrane) protein otuside of the cytoplasm

ligand-receptor interaction

initiates signal transduction

signal transduction

pathway converting signal to a response
1. ligand binds to receptor protein
2. relay molecules within cytoplasm react
3. cellular response activated

endocrine

hormones carried far through blood

paracrine

medium distance, ligand travels short distance to other cells

synaptic

short distance and sensory movement via neurotransmitter

contact-dependent

short distance, signaling cell is on the surface of the target of the target cell

G-protein coupled receptor

largest family of receptors in animals, 7 transmembrane domains, signal through GTP-binding proteins, many taste receptors

Turn on G-protein

exchange GDP for GTP

Turn off G-protein

hydrolyze GTP

GPCR signaling

1. ligand binds to receptor protein, which exchanges G-protein's GDP for GTP, ligand leaves receptor
2. Activated G-protein activates another enzyme
3. G-protein hydrolyzes GTP to GDP, deactivates enzyme

G-protein

on and off configuration, activates other enzymes, within cytoplasm

papilla

have taste buds with sensory receptor cells

sensory receptor cells

express a different taste receptors, attached to sensory neurons

sensory neurons

transmit taste signals

bitter taste signal transduction

1. bitter tastant binds to receptor protein as ligand
2. activate G-protein
3. G-protein activates phospholipase C to cleave PIP into DAG and IP3
4. IP3 binds to receptor protein on ER membrane to release Ca2+
5. Calcium causes ATP to be released neurotransmitter, causes Na+ to enter, depolarizing membrane

development

events in changing from a simple to more complex form

genomic equivalence

all cells in the body have the same genetic material

differentiation

process of cell becoming more specialized in structure and function

cell determination

potential fates become more limited until cell is committed to one fate

stem cells

give rise to differentiated cells, capable of continued divisiont

totipotent

cell can become any tissue (embryo or extra-embryonic)

pluripotent

cell can give rise to all adult cells

multipotent

cell can become a limited number of cells

unipotent

cell can only become one type

embryonic cell stem type

pluripotent

adult stem cells

multipotent

model organism

an organism selected as a representative organism for study

How to identify genes involved in vulva

1. Make mutants
2. Look for mutants without vulva
3. Map and sequence mutants
4. Identify genes encoded growth factors and receptors

Epidermal growth factor type

paracrine signal

anchor cell

secretes inducer ligand that influences cell fate by activating receptor

primary fate

high EGF

secondary fate

lower EGF

protein phosphorylation

signaling by phosphorylation

protein phosphatase

removes phosphate

protein kinase

adds phosphate, requires ATP

tyrosine kinase

enzyme that can transfer a phosphate group from ATP to the tyrosine residues on specific proteins in a cell, functions as on/off switch in cellular functions

EGRF receptor type

receptor tyrosine kinase

tyrosine kinase receptor process

1. when EGF binds to site, receptor tyrosines monomers dimerize
2. activated regions phosphorylate each other, using 6 ATP
3. phosphorylated tyrosine kinases phosphorylate inactive relay proteins, kicking of cellular response

is cell fate determination reversible

yes

fertilization

first step in development
1. sperm penetrates follide cell layer and zona peliucida
2. membranes fuse
3. egg activated

fertilization signal

1. membrane fusion and egg activation stimulates phospholipase C zeta, splits PIP to IP3 and DAG, IP3 attaches to ER
2. Calcium comes out of ER
3. Cortical granules are released to block polyspermy signal

cleavage

cell division

blastula

formed during cleavage, a hollow ball of cells

morphogenesis

generation of ordered form and structure

gastrulation

cell and tissue movements while blastula folds inward, generating 3 germ layers

anterior

above brain

dorsal/posterior

behind

ventral/anterior

front

posterior

away from brain

noggin

dorsal inducer, antagonizes BMP, default

BMP

promotes ventral fate

homeotic mutants

class of mutations that leads to the appearance of normal body parts in the wrong locations

hox genes

DNA sequence called homeobox, controls body patterns

homeodomain

protein domain encoded by homeobox sequence, that binds to DNA and acts as a transcription factor

physiology

study of processes and functions of an organism and the connections between form and function

Extracellular matrix

collagen secreted by cells, fibers outside cells that cells live in, holds tissues together, visualized by electron microscopy

hemidesmosome

anchors intermediate filaments to ECM

desmosome

connects cells to other cells

tight junction

prevents leakage

gap junction

forms channel allowing molecules and electrical signals to pass

adherens junction

joins actin bundle in one cell to a similar bundle in another

epithelial

tissues on surface of organ

connective tissue

between epithelial tissues and muscles

muscle tissue function

moves food through guts

endocrine system

for regulation, hormones circulate in blood, slower, long last effects

nervous system

faster signaling, more temporary effects

negative feedback

maintains homeostasis, counteract change

sensor

detect change

temperature regulator

internal temperature is independent of external temperature

temperature conformer

internal temperature is equal to external temperature

hypothalamus

humans temperature sensor and osmolarity sensoyr

circadian clock

cycle of 24 hours that persists without external cues, more melatonin, lower heart rate, and lower temperature at night

timless and period genes

transcribed in nucleus during day, translated in cytoplasm at night, and go back into nucleus to block own transcription, degrade at day

vaccination

administration of antigenic material to stimulate adaptive immunity by subsequent infection by a pathogen, promotes antibody secretion and immune memory

pathogens

microbes that cause disease in otherwise healthy people (bacteria, fungi, viruses, etc.)

immune system

recognizes pathogens and responds with immune cells and proteins

innate immunity

earlier response, all animals recognize broad ranges of pathogens using a small set of receptors

innate immunity defenses

skin, mucous membrane, secretion, phagocytic cells, natural killer cells, antimicrobial proteins, inflammatory response

adaptive immunity

later response, only vertebraes recognize traits specific to certain pathogens, using a vast array of receptors

defenses

antibodies in body fluids, cytoxic cells defend against infection in body cells

leukocytes/innate immune system white blood cells

eat pathogens, three types: macrophage, neutrophil, dendritic cell

marcophage

antigen presenting cell to TH cells, phagocytic

neutrophil

phagocytic, attracted to tissues during inflammation

dendritic cell

antigen-presenting cell to native TH cells, activates native TC cells

pseudopodia

part of cell that surrounds pathogens to engulf them during endocytosis

phagocytosis

1. pseudopodia surrounds pathogens and engulfs them by phagocytosis in a vacuole
2. vacuole and lysosome fuse
3. destroy pathogens, release debris

histamine and cytokines

cause capillaries to dilate upon detecting pathogen, promotes B cell differentation

local response to infection

1. Mast cell and macrophage release histamine and cytokines to dilate capillaries
2. neutrophils leave blood stream and enter tissues to digest pathogens and debris, white blood cells die upon activation

lipopolysaccharide

part of the bacterial membrane recognized by the innate immune system

Toll-like receptors (TLR)

on phagocytic cells, recognize PAMPS and stimulate immune response

TLR4

lipopolysaccharide recognizing receptor

PAMP

pathogen associated molecule patterns, conserved molecules of pathogens for innate immune system

lymphatic system

immune cells travel through lymph nodes to generate response

lymophocytes

adaptive immune system white blood cells, T cells in thymus and B cells in bone marrow

adaptive immune response

ligand/receptor interaction between antigens and antigen receptors

antigens

substances that can trigger B or T cells, proteins/polysaccharides associated with pathogens

antigen receptors

receptors on T or B cells that bind antigens

epitope

part of an antigen that binds to a particular antigen receptor, correspond to different strains