Exam 1 Material

Question 1

what are glycoproteins made of?

Answer 1

2 amino acid chains and carbohydrate subunits

Question 2

what’s the difference between thymosin alpha-1 and beta-4?

Answer 2

a-1 regulates the immune system (signals release of T-cells from thymus gland), b-4 binds to actin and promotes cell migration (also tissue regeneration)

Question 3

what are prostaglandins?

Answer 3

Short acting 20 amino acid fatty acid hormones. Produced by almost every tissue in the body. It is a second messenger.

Question 4

contrast the function of thymosin and thymopoieten.

Answer 4

thymosin promotes the maturation of t-cells and stimulates production of IL2, IL2 receptor, and B-cell growth factor. thymopoietin tells T-cells where to go in the body

Question 5

[insert thymus hormone] is zinc-dependent.

Answer 5

thymolin

Question 6

what do leptin and ghrelin do?

Answer 6

ghrelin makes you hungry, leptin makes you hungry

Question 7

how does estrogen impact T-cells?

Answer 7

a drop in estrogen levels (i.e., menopause) –> activate T cells –> increased inflammation and bone resorption –> development of osteoporosis

Question 8

what are prohormones?

Answer 8

A precursor to hormones, cleaved in golgi apparatus by proteolytic enzymes.

Question 9

What is the most abundant type of hormone? How does it enter blood flow?

Answer 9

Peptide/Protein hormones, stored in vesicles and released by exocytosis.

Question 10

function of thymulin

Answer 10

Zinc dependent, facilitates t-cell differentiation.

Question 11

non-specific vs specific immunity

Answer 11

non-specific immunity - generalized immunity that all humans are born with (skin, chemicals like stomach acid and tears, generalized white blood cells, like macrophages)

specific immunity - learned by the body based on previous exposure to pathogens (i.e., B-cells and antibodies)

Question 12

What is Proopiomelanocortin (POMC)?

Answer 12

A precursor to many different hormones. Cleaved by proteolytic enzymes into different pieces that have different functions.

Question 13

What are the three major ways secretion rate of hormones is controlled?

Answer 13

1. stimulating substances, like sugar with insulin
2. Neuronal control of endocrine glands (stress/exercise stimulating sympathetic ANS)
   3.Other hormones regulating hormone secretion

Question 14

How were G-Protein’s discovered?

Answer 14

Gilman and Ross studied connection between adrenalin receptors and adenylate cyclase. Used cyc- mutant cell line that bound adrenalin but appeared to lack adenylate cyclase. This was in fact untrue. 1977, Gilman and Ross discovered a GTP binding protein that stimulates adenylate cyclase.

Question 15

key difference between peptide and steroid hormones?

Answer 15

steroids can enter the cell and bind to intracellular receptors, peptides have to bind to receptors on the plasma membrane

Question 16

steroids usually require [low/high] affinity binding proteins

Answer 16

low

Question 17

why is a radioimmunoassay useful?

Answer 17

assesses immunoreactive levels of a hormone since it uses an
antibody to a specific epitope rather than the entire molecule

Question 18

three major patterns of hormone secretion rate control

Answer 18

1. by other substance (increased blood sugar –> insulin release)
2. neuronal control
3. regulation by other hormones (TRH stimulates release of TSH)

Question 19

What is a way to measure calcium concentration?

Answer 19

Fluorescent dyes.

Question 20

what is wrong with mutant forms of ras?

Answer 20

impaired GTPase activity –> excessive growth –> tumors

Question 21

what does phosphodiesterase do?

Answer 21

turns cAMP into AMP

Question 22

what does phospholipase C do?

Answer 22

splits PIP2 into DAG and IP3

Question 23

describe septic shock

Answer 23

bacterial infection –> low blood pressure –> vasodilation –> organ failure

Question 24

what is the difference between how nNOS, iNOS, and eNOS are regulated?

Answer 24

nNOS and eNOS - highly regulated by calcium concentrations. requires a significant increase in calcium to activate
iNOS - largely calcium-independent due to its high affinity for calmodulin

Question 25

what is cholesterol synthesized from?

Answer 25

acetyl co-A

Question 26

_______ is the rate-controlling enzyme in the pathway to synthesize cholesterol.

Answer 26

HMG-CoA reductase

Question 27

______ occurs from buildup of LDL in/on arterial walls.

Answer 27

atherosclerosis

Question 28

LDL/HDL (select one) is bad cholesterol.

Answer 28

LDL

Question 29

_______ is the precursor to all steroid hormones.

Answer 29

cholesterol

Question 30

3 things cholesterol produce

Answer 30

steroid hormones, bile acids, vitamin D

Question 31

Describe cholesterol transport in the body.

Question 32

where do HDL and VLDL assemble?

Answer 32

ER of liver cells

Question 33

where do chylomicrons form?

Answer 33

intestines

Question 34

function of HDL

Answer 34

collects (scavenges) cholesterol from non-hepatic tissues and delivers to the liver

Question 35

function of chylomicron remnants

Answer 35

delivers dietary cholesterol to liver

Question 36

lipoprotein lipase

Answer 36

a water-soluble enzyme that hydrolyzes triglycerides in lipoproteins, like those found in chylomicrons and VLDLs.

Question 37

what does PCSK9 inhibitor (repatha) do?

Answer 37

prevents degradation of LDL-receptors --> increases hepatic clearance of LDL --> decreases serum LDL levels

Question 38

how is CHL excreted?

Answer 38

made into bile salts to be excreted

Question 39

_____ is the major site for cholesterol synthesis

Answer 39

liver

Question 40

describe the biosynthesis of cholesterol (five steps)

Answer 40

acetyl CoA ---(HMG CoA Synthase)--> HMG CoA --(HMG-CoA Reductase)--> mevalonate ---> IPP --> Squalene --> Cholesterol

Question 41

function of statins

Answer 41

inhibits HMG-CoA reductase, prevents formation of mevalonate and thus decreases biosynthesis of cholesterol

Question 42

exosomes derived from ______ downregulate blood glucose, treatment for diabetes mellitus

Answer 42

mesenchymal stem cells

Question 43

what is the consequence of macrophages consuming oxLDL?

Answer 43

formation of foam cell which can lead to atherosclerotic plaques

Question 44

3 sources of cholesterol

Answer 44

dietary cholesterol, de novo synthesis in liver, extrahepatic tissue biosynthesis

Question 45

3 major routes of cholesterol leaving liver

Answer 45

secretion of HDL and VLDL, free cholesterol secreted in bile, conversion to bile acids/salts

Question 46

Lipoprotein

Answer 46

a cluster of lipids, often with a monolayer membrane, together with an apolipoprotein

Question 47

______ is the main enzyme in bile acid synthesis

Answer 47

7-Alpha Hydroxylase

Question 48

what does ACAT do?

Answer 48

increases esterification of cholesterol for storage

Question 49

what happens to cholesterol synthesis when cellular AMP is high?

Answer 49

HMG-CoA Reductase is inhibited by phosphorylation, catalyzed by AMP-Dependent Protein Kinase. This kinase is active when cellular AMP is high, corresponding to when ATP is low.

Question 50

describe translational control of cholesterol

Answer 50

SREBP, a transcription factor, binds to SRE (sterol regulatory element). When sterol levels are low, SREBPs are released by cleavage of precursor proteins in ER membranes. translocate into the nucleus where they activate transcription of genes for HMG-CoA Reductase

Question 51

Enzymes which produce steroid hormones from cholesterol are located in _____ and _____

Answer 51

mitochondria and smooth ER

Question 52

true or false: steroid hormones are water-soluble and thus do not need binding proteins

Answer 52

false—they are not water-soluble and have to be carried in the blood complexed to specific binding globulins

Question 53

what is an example in which a steroid is secreted by one cell and is converted to the active steroid by the target cell?

Answer 53

an example is androgen which secreted by the gonad and converted into estrogen in the brain

Question 54

______ is precursor to all steroids, except calcitriol

Answer 54

Pregnenolone

Question 55

true or false: steroid hormones are usually secreted as they are synthesized

Answer 55

true

Question 56

Cholesterol synthesis ______ when ATP levels are low and ______ when ATP levels are high

Answer 56

decreases; increases

Question 57

5 types of steroid hormones

Answer 57

glucocorticoids, mineralocorticoids, androgens, estrogens, progestogens

Question 58

example of androgen

Answer 58

testosterone

Question 59

function of progesterone

Answer 59

prepares uterus lining for implantation of ovum

Question 60

glucocorticoids example and function

Answer 60

cortisol promote gluconeogenesis; favor breakdown of fat and protein; anti-inflammatory

Question 61

Mineralocorticoids example and function

Answer 61

aldosterone maintains blood volume and blood pressure by increasing sodium reabsorption by kidney

Question 62

where is estrogen produced?

Answer 62

ovaries primarily but also in adipose cells of males and females

Question 63

the ______ zone (zona ______) of the adrenal gland produces aldosterone

Answer 63

outer; glomerulosa`

Question 64

the ______ zone (zona ______) of the adrenal gland produces cortisol

Answer 64

middle; fasciculata

Question 65

the ______ zone (zona ______) of the adrenal gland produces corticosterone and androgens

Answer 65

inner; reticularis

Question 66

______ stimulates the release of LH and FSH from the pituitary gland

Answer 66

Gonadotropin-releasing hormone (GnRH)

Question 67

what happens if 17-hydroxylase is absent in the steroid synthesis pathway?

Answer 67

hyperaldosteronism (high salt content and increased blood pressure

Question 68

function of sertoli cells

Answer 68

synthesizes ABP (androgen binding protein) in testes, along with some growth factors for sperm cells). ABP combines with testosterone to allow for sperm cell production

Question 69

____ stimulates sertoli cells to synthesize ___

Answer 69

follicle-stimulating hormone (FSH); androgen binding protein (ABP)

Question 70

____ stimulates leydig cells to synthesize ___

Answer 70

luteinizing hormone (LH); testosterone

Question 71

______ is involved in rate limiting transport of cholesterol into mitochondria

Answer 71

StaR protein

Question 72

function of 5-alpha reductase

Answer 72

converts testosterone to DHT, which allows for differentiation of external genitalia in men

Question 73

function of aromatase

Answer 73

converts testosterone to estradiol, which allows for differentiation of a male hypothalamus

Question 73

what happens if there is a mutation in 5-alpha reductase?

Answer 73

internal male reproductive organs (testes) but no external genitalia

Question 74

function of ACAT

Answer 74

converts cholesterol into cholesteryl esters, which are stored in cells as lipid droplets. reduces steroid synthesis bc that pathway relies on free cholesterol.

Question 75

the ______ is a system of blood vessels connecting the hypothalamus with the ______ pituitary

Answer 75

hypophyseal portal; anterior

Question 76

the ______ is a bundle of axons that connects the hypothalamic nuclei with the ______ pituitary.

Answer 76

hypophyseal tract; posterior

Question 77

true or false: amino acid sequence modification results in minor modifications to zinc finger structure resulting in selective binding to DNA

Answer 77

true

Question 78

hormone response element

Answer 78

short sequence of DNA within the promoter of a gene that is able to bind to a specific hormone receptor complex and therefore regulate transcription

Question 79

An intracellular nuclear receptor (NR) is located in the cytoplasm bound to a _______

Answer 79

heat shock protein

Question 80

7 hypothalamic hormones

Answer 80

GnRH, CRH, TRH, PRH, dopamine, GHRH, somatostatin

Question 81

the paraventricular nucleus of the hypothalamus contains _____ and _____ neurons

Answer 81

magnocellular and parvocellular

Question 82

the supraoptic nucleus of the hypothalamus contains only ____ neurons

Answer 82

magnocellular

Question 83

The magnocellular neurons of the PVN and SON synthesize _______

Answer 83

vasopressin

Question 84

vasopressin is also known as ____

Answer 84

anti-diuretic hormone (ADH)