Unit 6: Systems within Organisms Flashcards
what are the 2 types of movement
movement within cells
locomotion (moving from one place to another)
motile vs sessile
motile = organisms that can do locomotion
sessile = organisms that remain in one location
what is the sliding filament model of muscle contraction
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
what is titin
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
role of antagonistic muscles in muscle relaxation
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
structure and function of motor units in skeletal muscle
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
what is the role of skeletons
muscles provide pulling force, skeletons provide ANCHORAGE points
- levers
Fulcrum = pivot point of a lever
movement at a synovial joint
see B3.3.6 on iPAD
range of motion in a joint
- 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
internal and external intercostal muscles
inhaling:
ribcage up and out
external contract
exhaling:
ribcage in and down
internal contract
reasons for locomotion
finding food
finding a mate
escaping predators
migration
adaptations for swimming in marine mammals
- streamlined body (teardrop shape, no hair to reduce friction)
- airways (blowhole, mouth not connected to lungs)
- locomotion (fins, flippers, tails, blubber for buoyancy)
gas exchange in animals
universal function in organisms
properties of gas-exchange surfaces
- thin
- permeable to gases
- large surface area to volume ratio
- moist
maintenance of conc. gradients at exchange surfaces in animals
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
adaptations of mammalian lungs
diaphragm
intercostal muscles
abdominal muscles
ribs
ventilation of the lungs
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
measurements of lung volumes
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
adaptations for gas exchange in leaves
stomata = openings for gas exchange and water loss
distributions of tissues in a leaf
see b3.1.8
consequences of gas exchange in a leaf
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
how to measure stomatal density
stomata/cm^2
what is cooperative/allosteric binding of O2/CO2 to haemoglobin?
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)
adaptations of capillaries for exchange of materials between blood
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
foetal haemoglobin adaptations for transport of oxygen
Foetal haemoglobin has a higher affinity for oxygen than adult haemoglobin.
The capillaries in the placenta of a pregnant woman come very close to the capillaries of the foetus, allowing for molecular exchanges between the mother and foetus. Diffusion occurs due to the concentration gradient between the blood of the mother and foetus and the foetal haemoglobin’s greater affinity for oxygen, encourages diffusion of the mother’s oxygen to the foetus.
what is the Bohr shift?
high carbon dioxide conc. reduces haemoglobin oxygen affinity. this is good for respiring tissues
structure of arteries and veins
ARTERY:
- thick wall
- narrow lumen
- circular
- bumpy on the inside (inner corrugation)
- wall fibres visible
VEIN:
- thin wall
- wide lumen
- sometimes circular, but most of the time they are flattened
- no inner surface corrugation
- no wall fibres visible
adaptations of arteries for the transport of blood away from the heart
narrow lumen = high pressure
thick, muscular wall = contract/recoil
elastic fibres = elastic/strong, help push blood through, less energy required than a full contraction
muscular walls = contract to push blood through
adaptations of veins for the return of blood to the heart
wide lumen = low pressure, towards the heart
thin muscle wall = relies on the contraction of skeletal muscles
veins prevent backflow (valves)
role of a coronary artery
bring oxygenated blood from the aorta to the heart tissue itself
if there is an occlusion = coronary heart disease
(blocked with plaque)
–> can lead to a myocardial infarction)
adaptations of xylem vessels for water transport
dead hollow cells = maintenancee of a continuous water colume
lignin = prevents collapse
pits = water can pass through
xylem is on the INSIDE
exchange of substances between tissue fluid and cells in tissues
oxygen diffuses into cells
glucose moves into cells through sodium-glucose cotransporters)
carbon dioxide and waste moves out of cells
drainage of excess tissue fluid
85% of tissue fluid returns to capillaries, the other 15% drains into the lymphatic system, eventually draining back into the blood
single vs double circulation
mammals = need a separate low-pressure loop to the lungs (pulmonary loop)
fish = can pump blood at high pressure to the gills
what are pathogens
Pathogens are disease-causing organisms → typically bacteria, viruses, fungi, protists
what is the role of skin and mucous membranes in defence against disease?
skin = physical AND chemical barrier
mucous membrane = sticky mucus that traps pathogens
sealing of cuts in skin by blood clotting
- platelets (cell fragments) attach to site
- platelets release clotting factors
- prothrombin is converted to thrombin
- thrombin converts fibrinogen to fibrin
- fibrin forms a mesh to trap platelets and blood cells
innate vs adaptive immune system
innate = phagocytes (constant throughout the organism’s life), not specific
adaptive = lymphocytes (builds memory/immunity through life), specific
types of blood cells
- erythrocytes (red blood cells)
- leucocytes
–> phagocytes
–> lymphocytes
——> T-cells
——> B-cells
———-> plasma cells
———-> memory cells
infection control by phagocytes
phagocytes, engulf pathogens via endocytosis
enzymes inside lysosomes destroy pathogens
infection controlled by lymphocytes
lymphocytes produce antibodies
antibodies bind to antigens on pathogens
- tag it for destruction
- prevent it from binding w other host cells
antibodies are specific to antigens so we need a lot of diff. types of lymphocytes to make lots of diff types of antibodies
what are antigens and their role?
recognition molecule on the surface of a cell/virus (are glycoproteins)
–> antigens stimulate immune responses
–> antibodies are specific to antigens
blood group antigens
A: Anti-B, A antigen
B: Anti-A, B antigen
AB: no antibodies, A and B antigen
O: anti-A and anti-B, no antigens
activation of B-cells by T-cells
- pathogens engulfed by phagocyte
- antigen presentation on the outside of macrophage
- t-cells bind to the antigen and become activated
- activated t-cell binds to specific lymphocyte
- b-cell activates
- b-cell will clone (mitosis)
- differentiate into plasma cells
–> grow
–> produce organelles for antibody production - will secrete antibodies
what is HIV
human immunodefiency virus
what is AIDS
HIV –> AIDS
after HIV destroys helper T-cells
most people die from opportunistic infections, because no more T-cells
what is an antibiotic
chemicals that disrupt prokaryotic metabolism (so, good for bacterial infection, not viral infections)
evolution of resistance to several antibiotics in strains of pathogenic bacteria
resistance caused by mutation, antibiotics kills competitors, resistant strains become dominant
to prevent = only take antibiotics if needed, develop new antibiotics, restrict use of antibiotics for farm animal growth
zoonoses
infectious diseases that can transfer from other species to humans
i.e. tuberculosis = cattle (from raw milk),
rabies = dogs (from bite/scratch),
covid-19 = bats to humans
japanese encephalitis = pigs or birds passed by mosquitos
when does transpiration stop
outside air is humid
stomata closes at night
if the plant has lost its leaves
root pressure generation
active transport of mineral ions into the root, water will move into the xylem. increase in pressure
what is a companion cell
helps pump carbon compounds into sinks and into phloem out of source
what is a phloem sieve tube
allows carbon compounds through
