Bio 3

Missing Receptor In GPCR

Signaling Transduction Would Not Occurt

Too Many Receptors In GPCR

Response Would Be Much Stronger

Not Enough Receptors In GPCR

Less Sensitive Response

Mutation Changes Receptor Shape In GCPR

Ligand Would Not Bind Or G Protein Would Not Be Activated

Receptor Fails To Become Active In GCPR

G Protein Does Not Get Activated

Mutation Activates Receptor Without Ligand In GCPR

Unnecessary Signaling

G Protein Can’t Activate In GCPR

cAMP Production Would Be Decreased

GDP Can’t Exchange For GTP in GCPR

Will remain inactive, Effector Enzyme Will Not Be Stimulated Properly

G Protein + Receptor Protein Fail To Interact In GCPR

Cascade Interrupted between reception and enzyme activation

G Protein Stays Active For Too Long In GCPR

Excessive cAMP Production

G Protein Stays Active Not Long Enough In GCPR

Less cAMP Produced

Effector Enzyme Does Activate In GCPR

Little Additional cAMP Produced, PKA Not Activated Effectively

Mutation Changes Effector Enzyme Structure In GCPR

cAMP can’t be produced effectively

Effector Enzyme Stays Active Too Long In GCPR

PKA. and cAMP-dependent process activated strongly

Too Little cAMP Produced In GCPR

PKA Activation Decreases, Weakens Final Response

Too Much cAMP Produced GCPR

Response Becomes Excessive

cAMP Broken Down To Quick In GCPR

PKA Activation decreases, which weakens the final response

cAMP not broken down efficiently in GCPR

Response keeps going after ligand disappears, until proper shut off mechanism comes in

cAMP never detected by proteins in GCPR

Signal can’t be produced

PKA fails to activate in GCPR

Target proteins do not receive phosphorylation signal, response is reduced/absent

PKA remains active in GCPR

Target Proteins continue to be phosphorylated, disrupts normal regulation

PKA acts on wrong target proteins in GCPR

Change in activity and response

PKA doesn’t phosphorylate in GCPR

No signal can be produced

Target enzyme is missing/defective in GCFR

Response will not be carried properly

Target protein can’t be phosphorylated in GPCR

Response is reduced/altered

Target protein phosphorylated at the wrong time in GPCR

Response happens at the wrong time

Cell can’t carry out required response in GPCR

Message is still received, but produces the wrong response

Failure In Amplification In GPCR

Signal weakens, response will not be efficient

4 Components Of Cell Signaling

Signaling Cell, Signaling Molecule, Receptor Protein, Responding Cell

4 Steps Of Cell Signaling

Receptor Activation, Signal Transduction, Response, Termination

Example Of Multicellular Cell Signaling

Adrenaline released by the adrenal glands. It moves through the bloodstream (endocrine signaling) and increases heart rate and heart rate but decreases digestion.

Explain Receptor Activation

the ligand binds to the receptor which triggers change in the receptors shape

Explain Signal Transduction

After the ligand is bound to the receptor, the receptor connects to intracellular proteins, which initiates a signal transduction cascade of protein activation. Happens as protein one activating protein 2, protein 2 activating protein 3 etc…

Explain A Response

The change in cell behavior due to signal transduction. Examples include cell division, DNA replication, DNA expression, change in protein synthesis, change in enzyme activation and change in cell motility

Explain Termination

It turns the response off after the signal is produced. Examples include removing the activating functional groups (phosphate most likely)

Define Essential Nutrients

Nutrients that can’t be synthesized by cellular biochemical pathways and instead must by ingested. Humans are unable to synthesize 8 out of the 20. Without these we would starve.

Define Dietary Minerals

Chemical elements other than Carbon, Oxygen, Nitrogen and Hydrogen that are required in cells and must be obtained through food.

All Important Dietary Nutrients

Sodium, Chloride, Magnesium, Potassium, Phosphorus, Calcium, Iron And Zinc

Na Dietary Mineral Regulations

Too Much: Increase in concentration of dissolved particles in intestinal contents (shift in water movement; diarrhea/fluid loss); too little: decrease in nutrient absorption in the small intestine; none: Na dependent glucose absorption would not happen

Cl Dietary Mineral Regulations

Too much: stomach would be too acidic; too little: reduce ability to maintain normal fluid and acid-base balance; none: HCl production would not happen

Mg Dietary Mineral Regulations

Too much: Diarrhea, low blood pressure, muscle weakness, abnormal heart function; too little; muscle cramps, weakness, abnormal nerve activity, interfere with enzyme controlled reactions; none: cellular energy reactions and enzyme fucntions could not be maintained, the cells and muscles would fail to function properly

P Dietary Mineral Regulations

too much: disturb calcium and phosphate balance; too little: reduce ATP availability and impair energy dependent processes, muscle weakness, bone problems; none: cells would not maintain ATP, DNA, RNA, or phospholipid production, cell function would be impossible

K Dietary Mineral Regulations

too much: problems with electrical signals in the heart; too little: muscle weakness, cramps, constipation, and abnormal heart rhythms and intestinal muscle contractions may become less effective; None: membrane potentials, nerves and muscle functions could not be maintained and the heart and intestinal muscles would not be able to function properly.

Ca Dietary Mineral Regulations

too much: constipation, nasua, abdominal discomfort, kidney function issues, nervous system issues; too little: muscle spasms, abnormal nerve excitability and issues with bone health; none: cell signaling would fail

Fe Dietary Mineral Regulations

Too Much: damage tissue and organs; too little: iron deficiency anemia, reduce oxygen delivery; none: decrease in functional hemoglobin production and impairment in oxygen transport

Zn Dietary Mineral Regulations

too much: interference with copper absorption; too little: impari wound healing, immune function, growth, taste and smell; none: enzymes and proteins could not function, growth, cell division, tissue repair, immune function all severely disrupted.

Mechanical Digestion

Physically breaking down food

Chemical digestion

enzymes breaking down nutrient molecules

Absorption In The Small Intestine

Villi (multicellular) and microvilli (single cell) increase surface are available for nutrient absorption. Cells that line the small intestine are connected by tight junctions that prevent movement of substances between cells, instead directing products of digestion to be absorbed across microvilli surfaces.

Define Cell Surface Receptor

In cell membrane and bind signaling molecules that cannot easily pass through the membrane.

The two important examples of cell surface receptors

GPCR and Receptor Kinases

three characteristics of a GPCR

single polypeptide chain that has transmembrane spanning region, with the ligand binding site on the outside of the cell. It associates with a G-protein when activated, and the cellular response is rapid and short lived

Broad examples of GPCRs

hormones, small molecules, neurotransmitters, sight and smell signals

Explain all the steps of GPCR signal transduction (Phospholipase C Cascade)

First, the ligand binds with the seven membrane receptor which is able to transfer the unctivated GDP into the activated GDP. The activated GDP than binds with the effector enzyme, in this case Phospholipase C to activate it. Once the Phospholipase C is activated, it will release PIP2 which undergoes a hydrolysis reaction to produce 2 different second messengers. The first one is DAG, which does not need to change in any way in order to bind to the dependent kinases. The other one is IP2 which flows into a calcium bank which then release the calcium to bind to the dependent kinases. The kinases involved here are DAG+CA2+ dependent kinases. Now that they are bound the kinases phosphorylate to add a phosphate group to them. Now the phosphate-bound kinases release a signal to the body. Once the signal is received the ligand will unbind and everything will be terminated, stopping the signal.

Explain all the steps of GPCR signal transduction (Adenyl Cascade)

First, the ligand binds with the seven membrane receptor which is able to transfer the unctivated GDP into the activated GDP. The activated GDP than binds with the effector enzyme, in this case Phospholipase C to activate it. Once the Phospholipase C is activated, it will release ATP which hydrolyzes to become the second messenger cAMP. The cAMP messengers then bind to the cAMP dependent kinases. Now that they are bound the kinases phosphorylate to add a phosphate group to them. Now the phosphate-bound kinases release a signal to the body. Once the signal is received the ligand will unbind and everything will be terminated, stopping the signal.

Signal Amplification

Signal amplification means a single receptor activates many G proteins which activate even more effector enzymes. Basically, each step produces more of what the step before them did. Amplification happens in the cytosol.

Define the importance of signaling transduction where the signaling molecules involves heart cells and adrenaline activated kinases

Once they are both activated they lead to an opening of the calcium channels that are present in heart muscle cells. Results in influx of calcium ions which results in shorter intervals between muscle contractions, leading to an increase in heart rate, blood flow to the brand and skeletal muscle to deal with stress.

How does termination happen

can happen many ways, some example include hydrolysis of the GTP protein, turning it back to GDP. degrading the enzymes in the cytosol, for example turning cAMP just into AMP, or phosphatase enzymes removing phosphate groups.

Where does the digestive system start

the mouth

everything that happens in the mouth during the digestive system

amylase is produced by the salivary glands, which break down carbohydrates; lipase is secreted from the tongue, which breaks down lipids; the teeth preform mechanical digestion by breaking up the food, the tongue pushes the food to the back of the mouth where the pharynx connects the mouth and nasal cavity to the stomach and lungs.

What would happen if amylase secretion was not regulated correctly

carbohydrates (starch) would not be broken although chemical digestion would still occur in the stomach secreted by the pancreas from the amylase secreted there. If there is no amylase secretion anywhere, then the starch would not be able to be fully digested. If there were too much amylase, it would not matter as much because the starch would impact how much is secreted.

Second step in the digestive system

the epiglottis allows the food into the pharynx which then moves down the esophagus to the stomach by peristalsis

Define Peristalsis

series of involuntary , wave like contractions and relaxations that push food, fluid and waste through the digestive tract. Think of squeezing s pipe of frosting.

Where does the bolus go after it is done in the esophagus

the stomach

explain the first step of digestive regulation

A peptide hormone secreted by the cells lining the stomach called gastrin stimulate the cells lining the stomach to increase the HCl secretion. It is an example of negative feedback because it is secreted when pH levels are too high, it ultimately lowers the pH back down in your stomach. If there is a reduction or absence in gastrin production then there would be a decrease in HCl production which would increase the stomach acidity and decrease the amount of pepsin that helps break down proteins. If there is too much then it would produce too much HCl and potentially irritate the lining of the stomach

What are the two major specialized structures in mammals that help with feeding

a specialized jaw joint called the temporomandibular joint and the diversity of teeth.

Importance Of Incisors

Help with biting

Importance of canines

help with piercing through meat

importance of molar and premolars

help with crushing and shredding tougher foods

Difference in molars and premolars in herbivores

they have prominent surface ridges which help shred through tough plant material before it is swallowed and digested.

What do canines and incisors in herbivores prominently do in herbivores

biting grasses and leaves

Function on mucus in the stomach

protects the stomach wall from being damaged or digested

main functions of the stomach

digestion and storage

Define what the pyloric sphincter is

connects the stomach to the duodenum, allows dor small amounts of food to enter at a time

Secretions in the stomach

HCl, pepsinogen/pepsin, gastrin, lipase

Function of HCl in the stomach

it’s main function is that it allows the low pH of the stomach to not damage the stomach. It is produced when sight, smell, or taste of food sends signal to brain, which then causes the brain to send signals down to the cells of the stomach which will then secrete gastrin which regulates the amount of HCl secreted.

Explain how pepsinogen relates to the digestive system in the stomach

Pepsinogen is an inactive enzyme released by cells. The production of gastrin allows for the secretion of HCl which alter the pepsinogen into an enzyme called pepsin. This pepsin is now activated as a result of the change in structure and breaks down proteins back into amino acids.

three sections of the small intestine

duodenum, jejunum, ileum

Function of the small intestine

the main function is for nutrient absorption although the duodenum can still participate in digestion.

all secretions that end up in the small intestine

lactase (secreted by epithelial cells in the small intestine), lipase, amylase, trypsin, nuclease, bicarbonate cells (all secreted by the pancreas) Cholecystokinin (CCK), produced by the the cell linings of the duodenum and sodium ions, regulated by sodium potassium pump

function of lactase

enzyme that breaks down lactose into glucose and galactose

Function of trypsin

Breaks down proteins

Second step of digestive regulation

when the small intestine senses acid chyme, the small intestine releases a hormone called secretin which sends signals to the pancreas to release bicarbonate cells which neutralize the acid produced by the stomach now that it is done with actual digestion and in the small intestine. If the secretin hormone is absent or reduced, then the acidity from the stomach will carry on to the small intestine and damage it. If there is too much than the production of bicarbonate cells will be excessive and the rest of digestion could be impacted, it could not.

3rd step in digestive regulation

when the small intestine senses fats and proteins, the cells lining the duodenum secrete CCK which causes the gallbladder to contract and release the bile stored in there. The bile then breaks down remaining fats left in the duodenum in order for the rest of the small intestine to act out nutrient absorption. If there is an absence or reduction in CCK being produced then fats will not be broken down correctly, while if there is too much CCK produced then there will be an excessive prolonged response in digestion, potentially causing discomfort.

Define endocrine signaling

occurs when the signaling molecules travel through the bloodstream

Define Paracrine Signaling

occurs when the signaling molecule travels moves by diffusion between 2 cells, it takes form of a water-soluble molecule such as a growth factor

Define Growth Factor Molecule

a type of signaling molecule that causes responding cell to grow, divide, differentiate

Define Neurotransmitters

A signalling molecule released by a neuron

Define Autocrine Signaling

occurs when there is a signal being produced between two different parts of one cell. The cell is just signaling itself

Define contact-dependent signaling

occurs when signaling involves direct contact between two cells (embryos)

signaling cell produces too much/too little of it’s signaling cell

results in too much or too little message available which results in a weak/excessive response

signaling cell produces no signaling molecule

no message is sent, so there is no signal dependent response

signaling cell produces molecule too early

signal arrives before it is needed, resulting in a premature response

signaling cell produces molecule too late

the signal arrives after it is needed resulting in a delayed response

the signaling cell releases the molecule for too long

the signal will continue longer than needed resulting in prolonged response

signaling cell cannot release signaling molecule

the molecule may be made, but it will be kept in the cell resulting no response

signaling cell releases molecule too quick

large amount reaches the target cells in a short time results in a rapid response.

signaling cell releases molecule in the wrong location

the signal will not reach the intended target resulting in reduced response or effects on an unintended cell

signaling cell releases molecule when it should be stopped

the signal will persist unnecessarily resulting in unnecessary/prolonged response

signaling molecule is mutated

the shape and chemical properties would change resulting in a faulty in function