Module 3 Overview (Chemical and Electrical Signals)

Question 1

Communication between cells is known as _____________, and communication within a cell is known as _____________.

Answer 1

INTERCELLULAR SIGNALING (latin INTER- means BETWEEN)
INTRACELLULAR SIGNALING (latin INTRA- means INSIDE)

Question 2

What are chemical signals that are passed between cells known as?

Answer 2

LIGANDS! (EX: HORMONES AND NEUROTRANSMITTERS)

Question 3

Describe DIRECT SIGNALING

Answer 3

ALSO KNOWN AS “JUXTACRINE SIGNALING,” This involves communication between cells that are in DIRECT CONTACT, and this type of communication tends to use GAP JUNCTIONS (animal cells) OR PLASMODESMATA (plant cells)

Question 4

Describe AUTOCRINE SIGNALING

Answer 4

When a ligand ACTS ON THE SAME CELL IT RELEASED FROM

Question 5

Describe PARACRINE SIGNALING

Answer 5

When a LIGAND DIFFUSES IN SMALL AREA AND ONLY ACTS ON NEIGHBORING CELLS (CLOSE PROXIMITY) —-> think NEURAL SIGNALS AND HOW THEY TRAVEL BETWEEN SYNAPSES ON ADJACENT NEURONS!

Question 6

Describe ENDOCRINE SIGNALING

Answer 6

This is HORMONAL SIGNALING —> carried throughout ORGANISM’S BODY THROUGH VASCULAR SYSTEM TO ACT ON CELLS THAT COULD BE MUCH FARTHER THAN WHERE THE LIGAND WAS RELEASED FROM

Question 7

Describe PHERMONES

Answer 7

Signals that are RELEASED INTO ENVIRONMENT AND ACT ON CELLS OF ANOTHER INDIVIDUAL

Question 8

Describe the BASIC CRITERIA for a HORMONE

Answer 8

1) IS SECRETED FROM CELL OR GLAND INTO VASCULAR SYSTEM
NOTE: in the case of MICROBES, it is released into the ENVIRONMENT since they lack VASCULAR SYSTEMS **
2) MUST ACT ON DISTANT CELLS IN OTHER LOCATIONS or COMMUNITY (IN CASE OF MICROBES***)
3) HAS LARGE EFFECTS with even SMALL AMOUNTS OF MOLECULE
4) CAUSES RESPONSE SOLELY IN SPECIFIC TARGET CELLS
5) CAUSES a CHARACTERISTIC RESPONSE (expected, CONSISTENT)
6) PART OF FEEDBACK LOOP`

Question 9

Describe the FOUR MAJOR CATEGORIES OF HORMONES

Answer 9

-PEPTIDE HORMONES are small proteins
-AMINO-ACID DERIVED HORMONES are modified amino acids (the building blocks of proteins)
-STEROID HORMONES are small organic compounds with characteristic carbon ring structures
-GAS HORMONES are gases capable of acting like ligands

Question 10

Which of the FOUR MAJOR CATEGORIES OF HORMONES is ABLE TO PASS THROUGH THE PLASMA MEMBRANE? WHICH CANNOT?

Answer 10

PEPTIDE AND AMINO-ACID DERIVED are HYDROPHILLIC, cannot PASS THROUGH MEMERANE —> hormones must BIND TO RECEPTORS ON SURFACE OF CELL
STEROID AND GAS HORMONES are SMALL AND NON-POLAR, can PASS through MEMBRANE —-> HORMONAL RECEPTORS INSIDE CELL

Question 11

WHAT are the BASIC STEPS OF HORMONAL SIGNALING?

Answer 11

STEP 1: SIGNAL RECEPTION
STEP 2: SIGNAL TRANSDUCTION (necessary for hormones that cannot PASS THRO CELL MEMBRANE –> PEPTIDE AND AMINAO ACID DERIVED HORMONES)
STEP 3: SIGNAL AMPLIFICATION
STEP 4: SIGNAL RESPONSE: POSITIVE OR NEGATIVE FEEDBACK?

Question 12

T/F NO ONE LIGAND CAN EXHIBIT MULITIPLE RESPONSES BECAUSE THE PROCESS IS HIGHLY SPECIFIED

Answer 12

FALSE!
DIFFERENCES IN PROTEIN EXPRESSION, RECEPTORS AND SUBSEQUENT ACTIVATED PATHWAYS, AND INTERACTING SIGNALS (SIGNALING CROSSWALK) are all POSSIBLE —> CAUSE VARIATIONS IN THE RESPONSES OF A PARTICULAR LIGAND

Question 13

WHAT are the TYPICAL HORMONES RELEASED BY THE HYPOTHALAMUS?

Answer 13

1. GROWTH-HORMONE RELEASING HORMONE: stimulates release of growth hormone (GH) from the anterior pituitary
2. CORTICOTROPIN-RELEASING HORMONE: stimulates release of ADRENOCORTICOTROPIC HORMONE (ACTH) from the anterior pituitary
3. THYROTROPIN-RELEASING HORMONE: stimulates release ofÂ
4. THYROID-STIMULATING HORMONE (TSH) from the anterior pituitary
5. GONADOTROPIN-RELEASING HORMONE: stimulates release of follicle -stimulating hormone and luteinizing hormone (FSH AND LH) from the anterior pituitary
6. ANTIDIURETIC HORMONE (vasopressin): promotes reabsorption of water by kidneys; stored in posterior pituitary
7. OXYTOCIN: induces uterine contractions labor and milk release from mammary glands; stored in posterior pituitary

*recognize how A MAJORITY ARE AFFTHE A/P PITUITARY, HYPOTHALAMUS HORMONE SIGNALS FIX PITUITARY INTO GEAR

Question 14

What is the PITUITARY GLAND known as?

Answer 14

The MASTER GLAND

Question 15

What is the PRIMARY DIFFERENCE BETWEEN ANTERIOR AND POSTERIOR PITUITARY?

Answer 15

ANTERIOR LOBE produces and releases hormones and POSTERIOR LOBE DOES NOT PRODUCE hormones this is done by HYPOTHALAMUS—does RELEASE THEM INTO CIRCULATION THO***

Question 16

What HORMONES are PRODUCED AND RELEASED BY ANT. PITUITARY?

Answer 16

1. GROWTH HORMONE: stimulates growth factors
2. ADRENOCORTICOTROPIC HORMONE (ACTH): simulates adrenal glands to secrete glucocorticoids such as cortisol
3. THYROID-STIMULATING HORMONE: stimulates thyroid gland to secrete thyroid hormones
   4.FOLLICLE-STIMULATING HORMONE (FSH) and LUTEINIZING HORMONE (LH): stimulates production of gametes and sex steroid hormones
4. PROLACTIN: stimulates mammary gland growth and milk production

Question 17

WHAT HORMONES are PRODUCED BY HYPOTHALAMUS, but STORED IN POS. PITUITARY?

Answer 17

1. ANTIDIURETIC HORMONE: promotes reabsorption of water by kidneys; stored in posterior pituitary
2. OXYTOCIN: induces uterine contractions during labor and milk release from mammary glands during suckling; stored in posterior pituitary

Question 18

What are the HORMONES PRODUCED IN THE THYROID GLAND?

Answer 18

THYROXINE (T4) AND TRIIODOTHYRONINE (T3): increase the basal metabolic rate, affect protein synthesis and other metabolic processes, help regulate long bone growth (synergy with growth hormone)

Question 19

What HORMONES are produced by the ADRENAL GLANDS (HINT: THERE ARE TWO PARTS OF THE ADRENAL GLANDS, AND EACH HANDLES A DIFFERENT ASPECT)

Answer 19

MINERALOCORTICOIDS, SUCH AS ALDOSTERONE: increases reabsorption of sodium by kidneys to regulate water balance

GLUCOCORTICOIDS, SUCH AS CORTISOL AND RELATED HORMONES: long-term stress response hormones that increase blood glucose levels by stimulating synthesis of glucose and gluconeogenesis (converting a non-carbohydrate to glucose) by liver cells; promote the release of fatty acids from adipose tissue
adrenal medulla:
EPINEPHRINE (ADRENALINE) AND NOREPINEPHRINE (NORADRENALINE): short-term stress response (“fight-or-f`light”) hormones that increase heart rate, breathing rate, cardiac muscle contractions, blood pressure, and blood glucose levels; accelerate the breakdown of glucose in skeletal muscles and stored fats in adipose tissue; release of epinephrine and norepinephrine is stimulated directly by neural impulses from the sympathetic nervous system

Question 20

WHAT HORMONES ARE RELEASED BY THE PANCREAS?

Answer 20

INSULIN: decreases blood glucose levels by promoting uptake of glucose by liver and muscle cells and conversion to glycogen (a sugar storage molecule)
GLUCAGON: increases blood glucose levels by promoting breakdown of glycogen and release of glucose from the liver and muscle

Question 21

What would happen if you surgically removed the PROTHARACIC GLAND of a developing insect larva?

Answer 21

IT WOULD CAUSE ARRESTED DEVELOPMENT -> protharacic gland releases ECDYSIS, which is essential to METAMORPHOSIS AND MOLTING