Huckle Exam 1

Intercellular Communication; Gene Expression, Cell Cycle, and Programmed Cell Death; Metabolism

ligand

chemical signals which are usually water soluble, extracellular compounds

receptors

proteins that typically reside in the plasma membrane of a cell to receive ligand signals

second messengers

usually metabolites of abundant, pre-existing cellular components produced as a result of the ligand-receptor interactions

signal transduction

a cascade of protein phosphorylation reactions in which protein kinase enzymes can be activated catalytically by phosphorylation and then activate distinct downstream kinases

selective recognition, means of signal amplification, appropriate response, mechanism of control

What four features do sensing and signaling systems have in common?

receptor-signal complex

Selective recognition of an arriving signal is a feature of sensing/signaling systems accomplished by the formation of a _______________________

second messengers, protein phosphorylation

What are two means of signal amplification that sensing/signaling systems use?

second messengers

soluble, intracellular components used to amplify an arriving signal during intercommunication of cells

reversible

______________ protein phosphorylation is a ubiquitous means of signal transduction used in sensing/signaling systems for signal amplification

graded (more stimulus/duration = stronger response)

Cell sensing/signaling systems should have a _______ nature based on the signal they receive

nature, duration

A cell’s response to a received signal should be appropriate in its _________ meaning the biochemical response matches the biological one, and in its ___________ in terms of whether it has a short or long term response

feedback control systems, desensitation/re-sensitation

What two mechanisms of control might cells use in their sensing/signaling systems

ubiquitous

Protein phosphorylation and dephosphorylation is a ___________ way of quickly changing a system on or off

transmembrane

______________ proteins such as G-coupled proteins and ion channels are common structural strategies for receptors of ligands to convert an external signal to an intracellular response

cAMP

What is the classic secondary messenger that serves as a model example of secondary messengers in many cell communication systems

balance

Signals arriving to a cell together to create opposite effects requires ___________ to create the net desired effect

rapid, permanent

Cell responses to extracellular signals can be ________ and leave the cell essentially unaltered or can be ___________ by stimulating cell division or differentiation, or some combination thereof

rapid

_______ responses to extracellular signals, such as contraction or secretion, are transient or reversible

longer-term

_________ responses to extracellular signals include changes such as mitosis, altered gene expression, differentiation, or a permanent change in phenotype

regulated gene expression

Allows the development of differentiated cellular phenotypes because only a subset of genes is expressed, and their relative magnitude and timing determines phenotype

central dogma

The flow of biological information from DNA to DNA (replication), DNA to RNA (transcription), and RNA to protein (translation)

RNA polymerase

RNA transcription involves the action of an enzyme complex, ________________, that can assemble an RNA polymer whose sequence corresponds to the coding strand of DNA

transcription factors

proteins that regulate gene expression by binding to specific DNA promoter regions to prevent or allow transcription to occur

cell surface

Where are signal transduction pathways activated?

cell cycle

The ____________ is an expensive process requiring energy and materials and is HIGHLY regulated with many checks controlled through phosphorylation of protein kinases

multi

Many cell signaling pathways, including those of gene expression and mitosis, involve the formation of ______-subunit complexes

timing, magnitude, fidelity

At the level of RNA transcription, gene expression can be dysregulated with respect to the _________ or _________ of transcription rate, or the _________ of base-pairing

aneuploidy

cells with too many or too few chromosomes

apoptosis

regulated cell death which is essential for normal animal development and function

necrosis

cell death via disordered lysis of cells, with consequent inflammatory responses

metabolic pathways

Generation and consumption of energy equivalents (ATP, GTP, NADPH, NADH, etc.) for:

1. 1. Cell division and differentiation

2. 2. Biosynthesis of key macromolecular components

3. 3. Establishment and restoration of transmembrane gradients

4. 4. Responses to stimuli or injury

compartmentalization

__________________ describes the characteristic of cells in which events occur in different areas of the cell:

1. Uptake from extracellular space

2. Glycolysis in the cytosol

3. TCA Cycle and Oxidative Phosphorylation in the mitochondria

multiplicity

______________ of substrates describes the ability to recover energy equivalents (ATP) by oxidation of sugars, fatty acids, and amino acids

amino acids

_________________ are the “last resort” source of ATP via oxidation

glycolysis

A linked series of cytosolic enzymes whose activity is subject to control by the organism’s energy status and external signals which converts 1 glucose into 2 pyruvate molecules

2 ATP, 2 NADH

What is the net gain from glycolysis

cytosol

Where does glycolysis take place?

mitochondria

Where does the TCA Cycle take place?

TCA Cycle

Once pyruvate (3C) is converted to Ac-CoA (2C), it enters the ______________ which yields 3 NADH, 1 GTP, 1 FADH2, and 2 CO2

oxidative phosphorylation

______________________ uses energy derived from oxidation of NADH and FADH2 to create a proton (H+) gradient across the inner mitochondrial membrane. The energy from the decay of the proton gradient is used to drive phosphorylation of ADP to form 26 ATP molecules per molecule of glucose

oxidative phosphorylation

What step of glucose metabolism is the “heaviest hitter” in terms of its energy yield?

inner mitochondrial

The proton gradient across the __________________________________ membrane serves as the energy source to phosphorylate ADP into ATP during oxidative phosphorylation

NADH and FADH2

What are the energy sources for oxidative phosphorylation?

26

How many ATP molecules does oxidative phosphorylation yield per molecule of glucose?

H+

What ion gradient is used to drive phosphorylation of ADP into ATP during oxidative phosphorylation?

ATP

________ energy can be used:

1. To drive energy-requiring metabolic processes

   1. ex: de novo synthesis or interconversion of needed cellular components, physical movement of molecules, organelles, cells, tissues, limbs, etc.

2. To establish and maintain trans-compartmental gradients

   1. ex: ionic gradients across the plasma membrane

3. To coordinate and drive the global processes of cell division, survival, differentiation, and death

   1. ex: acute responses to stimuli and accessing information stored in DNA

exocrine pancreas

surrounds the endocrine pancreas and secretes digestive enzymes into the intestinal tract

endocrine pancreas

specialized cells that secrete, into nearby blood vessels, hormones including insulin and glucagon that act on numerous tissues to control the metabolism of glucose and other substances

glycogen

glucose polymer that is a stored form of chemcial energy

glucagon

hormone secreted by the endocrine pancreas that induces glycogenolysis in the liver and release of glucose into the blood

INCREASES blood glucose

insulin

hormone secreted by the endocrine pancreas that suppresses glycogenolysis in the liver, induces glycogen synthesis in muscle tissue, and increases absorption of glucose from filtrate in the kidney tubules

DECREASES blood glucose

increases

Insulin ____________ protein synthesis in all tissues by increasing transport of glucose and amino acids into cells

glycogenolysis

breakdown of glycogen in the liver to increase blood glucose

GLP-1

__________s stimulates insulin release and inhibits glucagon release

somatostatin

hormone that negatively regulates both insulin and glucagon release which decreases glucose and amino acid uptake from the intestine

upregulates, downregulates

Glucagon _____________ somatostatin production; Insulin _________________ somatostatin production

upregulates

Glucagon _____________ insulin release

downregulates

Insulin ______________ glucagon release

proinsulin

Large protein precursor that is cleaved to produce mature insulin

stimulators

Glucose, amino acids, and free fatty acids in the blood are ______________ of insulin release

enhancers

GLP-1, gastrin, and gastric intestinal peptides are _____________ of insulin release

inhibitors

Fasting, exercise, and insulin itself are _____________ of insulin release

100mg/dL

What is the approximate threshold of blood glucose where insulin gets released?

inhibited

Hormone sensitive lipase which mobilizes fat tissue is _____________ by insulin

stimulated

Hormone sensitive lipase which mobilizes fat tissue is ______________ by stress related hormones including cortisol and epinephrine

hypoglycemia

Having too much insulin secreted, from something such as an unregulated insulin-secreting tumor, causes __________________ and activation of the sympathetic nervous system

hyperglycemia

Diabetes causes _____________ as the primary symptom

1

Type ____ diabetes is caused by a decreased production of insulin and can be treated with insulin injections

2

Type _____ diabetes occurs when the tissue response to insulin is impaired, resulting in chronically increased blood glucose despite normal presence of insulin

glycation

A long-term problem associated with both Type 1 and Type 2 diabetes is ______ of proteins, in which glucose is added non-enzymatically, thus altering their function