week 1 (homeo)

Question 1

question: what is the difference between conformers and regulators?

Answer 1

• conformers match paraments of envrt.
  ⤷ do not have the mech. to reg. their own bodies
  ⤷ don’t func. optimally
• regulators maintain internal homeo. even if envrt. changes
  ⤷ energetically expensive to keep adjusting to keep internal stability

Question 2

question: are conformers or regulators more vulnerable of climate change?

Answer 2

• conformers
  ⤷ technically both but conformers a little more
• body can’t keep up if T keeps increasing
• homeostatic controls only work over limited range of parameters
  ⤷ has ideal range

Question 3

define: homeostasis

Answer 3

• actions of an organism to maintain optimal internal envrt. despite varying external conditions
• done w/ feebdack loops or reflex control pathways

Question 4

question: what are the requirements/components of homeo.?

Answer 4

• receptor
  ⤷ sensor to detect changes/stim.
• control center
  ⤷ receives and processes info
  ⤷ has set point
  ⤷ initiates a resp.
• effector
  ⤷ cell/organ that resp. to commands
  ⤷ can oppose or enhance stim.

Question 5

question: what is the diff. between -ive and +ive feedback loops?

Answer 5

NEGATIVE
- negating the change from stim.
- want to restore homeo. normal range
- primary mech. of homeo. reg.

POSITIVE
- enhancing/amplifying change from stim.
- want to restore systemic homeo.

Question 6

question: what is happening in the body during a fever? what about breaking a fever?

Answer 6

• bac. in body
• WBC recog. bac. and releases cytokines to elevate immune resp.
• cytokines go to hypothal. to increase set point 37 -> 39
• body adjusts and warms body to reach new setpoint

BREAKING FEVER
- set point returns to 37
- body adjusts back down

Question 7

question: why does the setpoint increase in a fever?

Answer 7

• to denature bac.
• to decrease rep. time of pathogen
• to increase time of necessary antibodies
  ⤷ faster immune resp.

Question 8

question: are fevers a stressor or the return to homeo.?

Answer 8

• both if considering immune sys.
• stressor if considering thermoregulation

Question 9

explain: broken blood vessel as an ex. of +ive feedback loop

Answer 9

• broken vessel -> release of clotting factors
• release of clotting factors cause sig. to release more factors

Question 10

name: examples of envrt. limitations that affect animal phys.

Answer 10

• light
• temp.
• water
• pH
• radiation

Question 11

question: what are the types of limitations that affect animal phys.?

Answer 11

• environmental
• scaling
• evolutionary

Question 12

define: scaling

Answer 12

• relationship between anatomical/physiology traits and body size
• SA of org. = exchange of material w/ envrt.
• V of org. = processing + using the materials

Question 13

explain: respiration scaling between small and large animals

Answer 13

• small animals = large SA:V
  ⤷ can breathe through skin
• large animals = small SA:V
  ⤷ can’t breathe through skin bc too large (wouldn’t get enough O2 to supply org.)
  ⤷ instead uses specialized struc. (lungs)

Question 14

explain: thermoregulation scaling between small and large animals

Answer 14

• small animals = large SA:V
  ⤷ can dissipate heat quickly
• large animals = small SA:V
  ⤷ can’t dissipate heat quickly
  ⤷ relies on homeo. reg. and structures to prevent overheating

Question 15

define: ectotherm vs endotherm (use conformer and regulator)

Answer 15

ECTOTHERM
- no internal control of body T
- thermoconformers

ENDOTHERM
- maintains constant body T
- generate internal heat to keep processes operating optimally
- thermoregulators

Question 16

define: physiological adaptation

Answer 16

• metabolic of physiological adjustment to improve ability of org. to cope w/ changing envrt.
• cell, tissue, or beha. lvl

Question 17

name: basic concepts of cell theory (4)

Answer 17

1. cells are the building blocks of all plants and animals
2. cells are prod. by div. of preexisting cells
3. cells are smallest units that perform all vital physiological func.
4. each cell maintains homeo. at cellular lvl.

Question 18

name: purposes/func. of cell mem.

Answer 18

GENERALLY: helps cell interact w/ envrt.

• anchor/isolate to envrt.
• recognition
• regulate exchange w/ envrt
• struc. support

Question 19

name: types of mem. prot. (position and func.)

Answer 19

POSITION
- integral
- peripheral

FUNC.
- anchoring
- recognition
- enz.
- receptor
- carrier
- channel
⤷ leak
⤷ gated

Question 20

define: passive vs active mvt. (across cell mem.)

Answer 20

• passive: move high -> low conc.
• active: move against conc. gradient
  ⤷ needs E (ATP hydrolysis)

Question 21

explain: passive transport (ex.)

Answer 21

• diffusion: small water-soluble mol. and ions just diffuse through mem. channels
• facilitated: larger molecules transported by carrier mech.

Question 22

question: is facilitated transport active or passive?

Answer 22

• technically passive
• can be both dep. on mvt. w/ or against conc/ gradient

Question 23

define: flux

Answer 23

• movement per unit time until no net flux
• net flux = 0 at equil.

Question 24

explain: simple diffusion in terms of flux

Answer 24

• molecules of solute mvt. from regions of high to low conc. until reach equil.
• even distribution = equil. = net flux of 0

Question 25

question: what is the relationship between diffusion coefficient (D), surface area (A), diff. in conc. (change in C), and distance (change in x), to net diffusion (flux, J)?

Answer 25

- increase permeability (D), more flux - increase SA (A), more flux - increase diff. in conc. (C), more flux - increase distance (x), less flux

Question 26

question: what carriers are involved in facilitated diffusion?

Answer 26

- **ion channels** ⤷ small pores for specific ions ⤷ either gated or leak - **porins** ⤷ ion channels but for larger mol. - **permeases** ⤷ act like enz.

Question 27

name + explain: types of prot. channels (3)

Answer 27

1. **ligand gated** - opens w/ ligand binding 2. **voltage gated** - opens w/ change in voltage 3. **mechano gated** - opens w/ stretch

Question 28

describe: mvt. for sodium potassium pump

Answer 28

- 3 Na+ out - 2 K+ in

Question 29

question: what type of mvt. is the sodium potassium pump?

Answer 29

primary active transport

Question 30

define: secondary active transport

Answer 30

- uses E in electrochem. gradient of one mol. to drive mvt. of other - ex. sodium-glucose co-transporter carrier

Question 31

question: what is an example where mem. transport is physiologically relevant (explain w/ flux)?

Answer 31

-RBC - need to keep correct shape to be able to fit through narrow capillaries - needs to be **isotonic** ⤷ no net flux ⤷ equal amounts solute and water inside and outside - **hypotonic** ⤷ solute higher inside ⤷ draws water in -> bloated, larger cell - **hypertonic** ⤷ solute higher outside ⤷ water leaves cell -> shriveled cell

Question 32

question: diff. between direct and indirect signaling?

Answer 32

- direct = close proximity ⤷ ex. gap junctions - indirect = distant cells ⤷ autocrine ⤷ paracrine

Question 33

explain: gap junctions for direct signaling

Answer 33

- gap junction made by connexons - sig. passed directly from one cell to another - in heart cells ⤷ replay info about when to contract - fast

Question 34

explain: indirect signaling (generally)

Answer 34

- sig. cell releases chem. messenger - messenger binds to receptor on target - induces activation of signal transduction pathway - response in target cell

Question 35

explain: each type of indirect signaling

Answer 35

AUTOCRINE - chem. sig. diffuses back to signaling cell ⤷ tells itself to resp. - serves as control (prevents always "on") PARACRINE - chem. sig. diffuses to nearby cell

Question 36

explain: indirect signaling in the endocrine system

Answer 36

- chem. messenger released by secretory gland - transported by circulatory system - longer lasting signals - slow acting - long distance

Question 37

define: exocrine signaling

Answer 37

- released by one indiv. and travels through envrt. for comms with other animals - ex. pheromones

Question 38

question: what is a ligand mimic?

Answer 38

- chem. with similar struc. to the natural ligand - can mimic the binding of a ligand to a receptor - can be agonists or antagonists ⤷ agonist = mimics natural resp. ⤷ antagonist = does not activate recep., only blocks it -> inhibits natural resp.