Animal Physio 1

Additional components of a cell membrane

proteins, carbohydrates, sterols

amphipathic

contains a polar and nonpolar part

Saturated tails

no double bonds, saturated with hydrogen atoms and form straight chains

Unsaturated tails

double bonds force a physical bend or kink in the carbon chain.

more bends = more flexible

When temperature goes down…

unsaturated hydrocarbon tails increase

allows for greater fluidity

Integral proteins

embedded in the phospholipid bilayrer

peripheral membrane proteins

noncovalently bonded to integral proteins or lipids but not within the bilayer

Channel protein

permits simple diffusion or osmosis through a membrane

Epithelium

sheet of cells that covers a body surface

compartmentalizes the body by forming boundaries

Tubules

epithelial cells

Long, cylindrical, and pipe-like

Follicles

epithelial cells

Round, oval, or spherical sacs

Tight junctions and septate junctions

occlude the intercellular space between two sells

desmosome

localized spot where contact between cells is strengthened

gap junction

localized spot where the cytoplasms of two cells communicate through tiny pores

protein structure

Primary structure: strings of amino acids held by covalent bonds

Tertiary structure: proteins 3D conformation, held by noncovalent bonds

Enzymes

speed up and regulate chemical reactions

enzyme + substrate ←> e-s complex ←> e-p complex ←> enzyme + product

Enzyme-catalyzed reactions

reversable

direction of reaction will move towards equilibrium

Allosteric modulation

modulation of the catalytic properties of an enzyme by the binding of nonsubstrate ligands to specific nonsubstratebinding sites, which are called regulatory sites or allosteric sites

Maximum reaction velocity is determined by

number of enzyme molecules present

catalytic effectiveness of each enzyme molecule, represented by kcat

kcat

number of substrate molecules converted to product each second by each enzyme at saturation

Catalyzed vs. uncatalyzed reaction

activation energy is greater without catalysis

How are enzymes able to catalyze reactions

specific binding sites

changes in molecular conformation

protein ligands

molecule that selectively binds w noncovalent bonds to a site on a specific protein that is structurally and chemically complementary

ex. ligand gated channels

the function/phenotype of a cell depends on the expression of _________

enzymes

Covalent modulation

change the shape of the protein that affects its catalytic properties

turns an enzyme “off” or “on”

ex. phosphorylation

The 5 time frames in which physiology changes

External responses:

1. Acute changes

2. Chronic changes

3. evolutionary changes

Internal responses:

4. developmental changes

5. Changes controlled by biological clocks

proteins evolve at the ________ and ______ level

amino acid/structural

gene/allele

Active transport

away from equlibrium

passive transport

towards equlilibrium

Chemical gradient

solutes diffuse down towards the LESS CONCENTRATED side of the membrane

Electrical gradient

solutes diffuse towards the side of the membrane with the OPPOSITE CHARGE

Simple diffusion

concentrations only move towards equlibrium

HIGH CONCENTRATION → LOW CONCENTRATION

Fick’s Law

quantifying simple diffusion

J= d x (c1 - c2)/X

Boundary layer

layer of diffusing particles around an animal cell

Electrochemical gradient

ions and solutes diffuse down their electrochemical gradient towards equilibrium through passive transport

Passive transport

TOWARDS direction of electrochemical equilibrium

Sodium-Potassium ATPase

primary active transport draws energy directly from hydrolysis of ATP → ADP

Secondary active transport

draws energy from an electrochemical gradient

ATP is used to instead create the electrochemical gradient

Cotransporter

moves two solutes in linked fashion in one direction

Counter transporter

moves two solutes linked in opposite directions

Osmotic pressure

the property of a solution - wiehter it will gain or lose water by osmosis

Freezing point

highest temperature capable of inducing freezing

Osmosis

passive transport of water across a membrane

LOW → HIGH

mechanisms of water crossing the cell membrane

dissolve and diffuse

aquaporin channels

essential amino acids

must be aquired fully formed from food/ outside source

lipids

diversity of lipids comes from the number of carbons on the carbon chain backbone

functional benefits of lipids

cell/interacelluar membranes

energy stores

reduce permeability of integument to water

Lipids can be …..

synthesized from carbon chains from the diet

stored

Carbohydrate structure

two monosaccharides + a disaccharide

Carbohydrate function

structural support and shape to cells

storage compounds

transport compounds

Carbohydrate nutrition

can be synthesized from carbon chains in dietary carbohydrates and gluconeogenesis

can be stored

no “essential” carbohydrates

Vitamins

organic compounds that animals must obtain in small quantities from food or other sources because they can’t be synthesized

Minerals

chemical elements

needed for proper protein function and synthesis

3 main foraging strategies

1. taking food items individually

2. filter feeding/grazing

3. working with symbionts

suspension feeding

collecting large numbers of food because they are small individually

collect food items in bulk

heterotropic

require organic compounds externally for energy

autotropic

can synthesize organic molecules from inorganic

photoautotrophs

can synthesize organic molecules from photon energy

chemoautotrophs

can synthesize organic molecules from inorganic chemical reactions

digestion

breakdown of food molecules by enzyme action into smaller chemical components

absorption

transfer of products of digestion from the lumen of the gastrointestinal tract to the blood/lymph

OR entry of molecules into the living tissues of an animal from outside those tissues

Hydrolytic enzymes

species can digest only the molecules it has enzymes to break up through hydrolytic reactions

Intraluminal enzymes

secreted in lumen of body cavity

membrane-associated enzymes

oftentimes in epithelial cells

intracellular enzymes

particles must first be taken into the cells to be digested

Polysaccharidases

breaks starch and glycogen down

Disaccharidases

membrane bound, midgut

Zymogen

an inactive precursor of an enzyme that requires a biochemical change to become active (ex. pepsin)

Animals are structurally _____

Dynamic

molecular constituents of an individuals body have to be rebuilt

new constituents are brought in from the environment

examples of how animals use energy

ions across membranes

solute transport

circulation

muscle contraction

protein synthesis

Chemical energy

can be used in all forms of physiological work

Electrical/mechanical energy

used by all animals but can’t do all forms of physiological work

Heat

temperature differences can’t be used do do work

but it is still important, temp levels are stable in animals

Transformation of energy is _________

inefficient

output/input

chemical energy → mechanical energy

metabolic rate

rate at which animal converts chemical energy to heat and external work

metabolic rates measured in

joules/time

Calorie

amount of heat needed to raise the temperature of 1g of water by 1C

(convertible to joules)

An animals metabolic rate determines:

-how much food it needs

-intensity of living

-drain on physiologically useful energy supplies

Homeotherm

Generate own internal heat, requires more energy

Ectotherm

relies on external sources in its environment to control its body temperature not its own internal metabolism

Basal metabolic rate

FOR HOMEOTHERM (aka endotherm)

measured in a THERMONEUTRAL zone

measured when fasting & resting

Standard metabolic rate

FOR ECTOTHERMS

measured when the animal is in the right temperature

measured when fasting and resting

Specific Dynamic Action (SDA)

the extra energy your body expends above its basal metabolic rate to digest, absorb, metabolize, and store the nutrients from a meal

relationship between size of meal and SDA magnitude

both increase & decrease with each other

Metabolic allometry

metabolic rate scales disproportionately with body mass

larger animals have lower energy use per gram of tissue than smaller animals

Does resting metabolic rate vary allometrically with individual body size?

Yes

Energy absorption efficiency

absorbed energy/ingested energy

major cellular source of energy

ATP

rate at which a cell cause use ATP depends on rate that a cell can ______ ATP

produce

How is energy drawn from food molecules?

ADP + P + energy from food molecules → ATP

Aerobic Catabolic Pathway

Glycolysis

The Kreb cycle

Electron transport chain

Oxidative Phosphorylation

3 main methods of ATP production

1. aerobic catabolic pathway

2. Anaerobic glycolysis

3. Phosphagen usage

Method of ATP production depends on…

-speed of energy needed

-duration of energy needed

-oxygen availability

-materials available to the cell

Anabolism

to build molecules

Catabolism

to breakdown molecules

aerobic catabolism

slower

more sustainable

oxygen needed

Glycolysis

starts with glucose

NADH electron acceptor

No O2 required

net 2 ATPs

2 pyruvic acids

Citric acid cycle

2 pyruvate go in

Net 2 ATPs from GTP

No O2 requred

NAD and FAD limited use

The electron transport chain

ADH2 and FADH2 donate electrons, regenerates NAD and FAD

oxygen as final electron acceptor

Oxidative phosphorylation

Forming ATP using energy released in the transport of electrons through the ETC

electrogemical gradient → ATP synthase