Unit 6: Systems within Organisms

movement within cells locomotion (moving from one place to another)

motile = organisms that can do locomotion sessile = organisms that remain in one location

striated muscle fibres has the stripes. this is caused by something called a sarcomere see B3.3.2 for structure when contract, myosin pulls the actin filaments + z-line closer see iPad for the model

titin = connects myosin to the z-line - biggest polypeptide it is very elastic (has spring motion) prevents z-lines from getting too far apart makes muscle contractions stronger when muscle is relaxed, titin is stretched contract = spring recoil

muscles that accomplish opposite movements (i.e. bicep and tricep) when one contracts, the other stretches, stretching the titin, which can recoil to make contraction stronger

neuromuscular junction: where a motor neuron meets a muscle fiber acetylcholine = transfers messages from neurons to muscles motor unit = motor neuron + all of the muscle fibers it connects to (B3.3.4 iPad) –> for coordinated contraction

muscles provide pulling force, skeletons provide ANCHORAGE points - levers Fulcrum = pivot point of a lever

see B3.3.6 on iPAD

• hinge joint = can only flex or extend • ball and socket joint = capable of rotation, adduction/abduction (side to side), protraction/retraction (up and down) can be measured with a goniometer

inhaling: ribcage up and out external contract exhaling: ribcage in and down internal contract

finding food finding a mate escaping predators migration

• streamlined body (teardrop shape, no hair to reduce friction) • airways (blowhole, mouth not connected to lungs) • locomotion (fins, flippers, tails, blubber for buoyancy)

universal function in organisms

• thin • permeable to gases • large surface area to volume ratio • moist

higher gradient = faster diffusion needs constant blood flow ventilation = moving air into and out of the lungs through dense networks of blood vessels fish = move fresh water through gills

diaphragm intercostal muscles abdominal muscles ribs

inhaling: 1. diaphragm and external IM contract 2. abdominal and interior IM relax 3. inc. chest cavity volume 4. pressure decreases 5. air is forced into our lungs exhaling: 1. diaphragm and external IM relax 2. abdominal and interior IM contract 3. dec. chest cavity volume 4. pressure increases 5. air is forced out of our lungs

ventilation rate: number of inhalations/exhalations per minute tidal volume: volume of air inhaled/exhaled in each breath vital capacity: maximum amount of air the lungs can hold inspiratory reserve vole: amount of air a person can inhale after a normal breath expiratory reserve volume: amount of air a person can exhale after a normal breath can use a spirometer or a bell jar to measure lung volumes

stomata = openings for gas exchange and water loss

see b3.1.8

transpiration = loss of water vapour from the leaves higher temp = more transpiration higher humidity = less transpiration guard cells can open and close stomata to control water loss can measure transpiration using a potometer

stomata/cm^2

haemoglobin can transport 4 oxygen molecules when oxygen binds to one of the haem groups, it causes a conformational change, increasing its affinity for oxygen = cooperative binding this is reversible haemoglobin w/ 3 O molecules will have the greatest affinity for oxygen. w/ 4 O molecules = no affinity. w/ 0 O molecules = least affinity (besides 0) allosteric binding CO2 will bind to the polypeptide regions of the molecule, known as the allosteric site of the polypeptide binding of CO2 = release of O molecules (BOHR SHIFT)

capillaries = site of diffusion into and out of the blood –> have a large surface area tissues that need lots of oxygen or nutrients have a high-density capillary network -pores = to increase permeability - fluid that comes out of the capillaries = tissue fluid (water, oxygen, glucose, ions) —> tissue fluid leaves the capillaries and flower between tissues —> materials diffuse into tissues, waste diffuses into tissue fluid —> fluid returns to capillaries