BIOD27: Endocrinology (TT1)

Question 1

what is the function of the parathyroid glands?

Answer 1

play an important role in regulating blood calcium

Question 2

what is the function of the atrial natriuretic peptide (ANP)?

Answer 2

promotes the urinary excretion of sodium from the body

Question 3

paracrines vs. autocrines

Answer 3

paracrines: exerts effects on local/nearby cells

autocrines: chemicals that exert effect on cells that produced them in the first place (ie. affects itself)

Question 4

attaches a sugar, usually to an “N” or “O” atom in an a.a. side chain

Answer 4

glycosylation

Question 5

adds an acetyl group to the N-terminus of a protein to increase stability

Answer 5

acetylation

Question 6

covalently links the “S” atoms of 2 different cysteine molecules

Answer 6

disulfide bond

Question 7

attaches a lipid to a protein chain

Answer 7

lipidation

Question 8

adds a phosphate to serine, threonine, or tyrosine

Answer 8

phosphorylation

Question 9

leptin vs. ghrelin

Answer 9

leptin: suppresses appetite

ghrelin: increses appetite

Question 10

what is the role of C-peptide in the prohormone?

Answer 10

helps to make sure that the 2 parts that need to be linked together has the right orientation for folding and so that we can put disulphide bonds in the right place (Connecting peptide)

Question 11

the rough ER is an _____ environment whilte the cytosol is an _____ environment

Answer 11

the rough ER is an oxidizing environment whilte the cytosol is a reducing environment

Question 12

an aqueous pore in the ER membrane through which secreted proteins pass during translation

Answer 12

translocon

Question 13

what helps create diversificaton in peptide hormones?

Answer 13

• transcription of multiple homologous genes
• transcription machinery at different sites on all genes
• alternative splicing of transcripts (exons)
• protein cleaved in different ways to create different fragments

Question 14

the only 2 locations within the vertebrate body where steroid hormones are produced

Answer 14

adrenal and gonadal

Question 15

most basic steroid hormone, as just involves removal of part of the cholesterol side chain

Answer 15

pregnenolone

Question 16

what are the 2 major places to find enzymes necessary for steroid hormone synthesis

Answer 16

mitochondria and smooth ER

_{(most found in smooth ER)}

Question 17

3 general types of reactions in steroid hormones

Answer 17

1. hydroxylations
2. dehydrogenations
3. C-C bond breakage

Question 18

what is the active form of vitamin D called?

Answer 18

calcitriol

Question 19

what are eicosanoids?

Answer 19

they are derivates of arachidonic (aka fatty) acids

Question 20

a protein that is always involved in forming vesicles within cells

Answer 20

clathrin

Question 21

what are the 3 major hormones that the pancreas produces?

Answer 21

• insulin
• glucagon
• somatostatin

Question 22

what are the advantages to a pulsatile hormone release?

Answer 22

• info can be coded in amplitude or frequency of pulses
• more energetically-efficient and less cellular stress
• prevents receptor desensitization

Question 23

what are 2 factors that determine half-life of hormones?

Answer 23

• how quickly it equilibrates w/ extravascular fluid and/or adipose tissue
• how quickly it is degraded

Question 24

transformation of steroids to get degraded?

Answer 24

reduction then conjugation before excretion (70% in urine, 20% in bile)

Question 25

the bigger K_D (dissociation constant) is, the (faster/slower) the rate of hormone degradation

Answer 25

the bigger K_D (dissociation constant) is, the **FASTER** the rate of hormone degradation

Question 26

rate constants: K₁ vs. K₂

Answer 26

**K₁:** rate at which hormone-receptor complex forms **K₂:** rate at which hormone receptor degrades

Question 27

states that cells express much higher concentrations of hormone receptors than is needed to bring about a maximum biological effect

Answer 27

spare receptor hypothesis

Question 28

intracellular receptors: zinc finger

Answer 28

**D box (C II):** generalized DNA binding region **P box (C I):** allows for protein to bind to a very specific DNA sequence

Question 29

posterior pituitary gland: components

Answer 29

infundibular stalk pars nervosa

Question 30

anterior pituitary gland: components

Answer 30

pars tuberalis pars intermedia pars distalis

Question 31

refers to bundle of axon running from hypothalamus to posterior pituitary gland

Answer 31

supraopticohypophyseal tract

Question 32

role of prolactin in different vertebrate groups

Answer 32

**mammals:** milk production **birds:** fat metabolism **fish:** salt and water balance **amphibians:** metamorphosis and maturation