BIO 106 - Final Exam

actin

actin

thin filaments

function: muscle contraction, cell mobility, cell division and cytokinesis, vesicle and organelle movement, cell signaling, and establishment and maintenance of cell junctions and cell shape

action potential spread in a normal heartbeat

action potentials spread rapidly through the heart’s electrical conduction system, causing a coordinated wave of muscle contractions

initiation —> spread —> contraction

resting heart rate of 60-100 bpm

amphibians

caecilians, frogs and toads (anurans), salamanders

• an early split in the tetrapods led to the 2 main vertebrate groups (amphibians and amniotes)

• most live in moist environments - the lose water easily through the skin, and eggs dry out if exposed to air

• some adults live on land but must return to water to reproduce

arthropods

huge and diverse group

• muscles attached to inside of rigid exoskeleton

• segmentation - each segment has muscles that operate that segment and its appendages

• jointed appendages allow complex movement and specialization

• rigid exoskeleton provides support in water or on land, protection from predators, and prevents drying out

arthropod relatives with segmented bodies and fleshy unjointed legs: velvet worms(onychophorans), tardigrades (water bears),chelicerates

the remaining arthropod groups are the mandibulates: myriapods (centipedes/millipedes), crustaceans, hexapods, pterygote

avian air sacs

expand and contract, acting like bellows to push air past gas exchange surfaces in the lungs

• air sacs don’t participate in gas exchange

• inhalation: fresh air goes to the posterior air sacs, then flows through parabronchi to anterior air sacs

• exhalation: fresh air in posterior air sacs is driven into parabronchi, while the stale air is exiting the parabronchi at the anterior end and anterior air sacs

bulk flow

flow of matter form one place to another

O2 and CO2 are transported by diffusion and bulk flow (no active transport)

diffusion is effective for moving gases over very short distances - all cells depend on diffusion for O2 to pass

calcium ions (Ca2+)

convert electrical energy into mechanical energy

role: activates myosin by shackling to troponin on the cytoskeleton; plays an important role in excitation-contraction coupling

cardiac output

volume of blood pumped per minute

chemical synapse

very narrow space between cells (synaptic cleft) that an action potential cannot cross

circulatory system

consists of muscular pump (heart), fluid (blood), series of conduits (blood vessels)

closed system - blood always remains within blood vessels

open system - blood exits vessels as it flows through the body (no distinction between blood and interstitial fluid)

cleavage

rapid series of cell divisions, but no cell growth (I, II, III)

• cells increase in # but get smaller and smaller

• cells end up with different cytoplasmic determinants

• these cells are called blastomeres (group - blastula)

• plane of cleavage determined by the orientation of the mitotic spindle

cocurrent gas exchange

the 2 fluid streams flow in the same direction

• water has a much higher O2 partial pressure than blood and O2 diffuses rapidly into the blood

common ancestors of animals

phylogenetic analyses of gene sequences has shown that all animals have a common ancestor (monophyletic)

• animal common ancestor was probably very different from any living animals; large multicellular animals appear to have evolved several times in different lineages

complete cleavage

cytoplasm is completely divided by each cell division

countercurrent gas exchange

the 2 fluid streams flow in opposite directions

• as blood flows along the gas exchange membrane and its O2 partial pressure rises, it encounters fresher water with higher and higher O2 partial pressure

• O2 partial pressure of water is always higher than that of blood

• more efficient than cocurrent

cross-bridges

formed when myosin and actin interact when the globular heads of myosin bind to actin

determination

cell fate is established

differentiation

cells become different from one another

electrical synapse

cells are joined by gap junctions where the cytoplasm is continuous; signals cross with essentially no delay

embryonic development

a fertilized egg is transformed into an embryo

excitation

when a nerve impulse arrives at the neuromuscular junction, an action potential is initiated in the muscle fiber membrane

excitatory postsynaptic potentials (EPSPs)

graded membrane depolarizations shift membrane potential towards threshold

function of grey crescent

helps establish polarity and is crucial for embryo development

• turns into Spemann’s organizer, a signaling center that “talks” with other tissues to direct development

• acts as organizer in the embryo

gas exchange membranes

thin layers of tissue where respiratory gases move between the environment and the internal tissues

gastrulation

involved movement of cells: the 3 germ layers are formed and the embryo becomes a gastrula

general characteristics of animals

• multicellularity

• heterotrophic metabolism

• internal digestion

• movement and nervous system

growth

increase in size by increasing cell number, cell size, production of extracellular material, or a combination

hyperosmotic

solution with higher osmotic pressure

hyposmotic

solution with lower osmotic pressure

inhibitory postsynaptic potentials (IPSPs)

shift membrane potential away from threshold; produce graded membrane hyperpolarizations

isosmotic

2 solutions have the same osmotic pressure

mammalian breathing system

inhalation: contraction of diaphragm expands the thoracic cavity, which pulls on the lungs and expands them; air is sucked in

exhalation: the diaphragm and intercostal muscles relax, allowing elastic recoil of the lungs and thoracic cavity to push air out

• conducting airways - conduct flowing air in and out of the lungs during inhalation and exhalation (trachea, bronchi)

• gas exchange occurs in the respiratory airways (bronchioles, alveolar sacs)

• tidal volume - amount of air that moves in and out of lungs per breath

• respiratory minute volume - total volume of air inhaled and exhaled per minute

morphogenesis

process leading to the final form of the animal

muscle contraction

• Z line: the Z discs move closer together

• H zone: shortens

• sarcomere: shortens, the primary structural and functions unit responsible for muscle contraction

• A band: doesn’t change i length, but A bands from different sarcomeres move closer together and eventually disappear

• actin and myosin pull towards the center of the sarcomere, increasing the zone of overlap

• I band: shortens

• M line: moves closer

muscle contraction steps

1. discharge of motor neuron at endplate

2. release of the neurotransmitter ACh at endplate

3. binding of ACh to its receptors

4. increased Na+ and K+ conductance in endplate membrane

5. generation of action potential at endplate

6. generation of action potential along muscle fibers

7. spread of potential along muscle fibers

8. release of Ca2+ from sarcoplasmic reticulum and diffusion to actin and myosin

9. binding of Ca2+ to troponin and thereby uncovering myosin binding sites on actin

10. formation of cross-bridges between actin and myosin and sliding of actin and myosin, producing muscle shortening

myofibrils

bundles of actin and myosin filaments arranged in repeating units called sarcomeres

• each sarcomere starts and ends with a z-line, which actin attaches to

• myosin filaments extend out from the M band in the center

• H zone and I band have no overlap of actin and myosin

myosin

thick filaments

function: converts chemical energy in the form of ATP to mechanical energy, generating force and movement

neuromuscular junction

chemical synapses between motor neurons and skeletal muscle cells

signals from the brain or spinal cord interact with muscle fibers to cause them to contract:

1. presynaptic terminal depolarization and ACh (acetylcholine) release

2. ACh binding and ion channel opening

3. postsynaptic membrane depolarization and muscle action potential generation

neurotransmitter

chemical messengers

function: to carry chemical signals from one neuron (nerve cell) to the next target cell (nerve cell, muscle cell, or gland)

• movement, sensation, heart rate, information processing, brain development

osmosis

the movement of water molecules through a semipermeable membrane from a region of high concentration to a region of low concentration

osmoregulation

the process by which an organism regulated the water balance in its body to maintain homeostasis

• freshwater fish: hyperosmotic to fresh water because water passes in across gills and other membranes by osmosis

• Na+ and Cl- are more concentrated in blood plasma than in fresh water, and thus pass out by diffusion

osmotic pressure

measure of the total concentration of solutes; determines direction of water movement

• water moves from regions where osmotic pressure is low (high water concentration) to regions where its high (low water concentration)

oxygen loading/offloading

loading: the process by which hemoglobin binds oxygen to form oxyhemoglobin, happens in lungs

offloading: the process of oxygen unbinding from hemoglobin in red blood cells as blood flows through metabolizing tissues, occurs in areas with lower oxygen concentration (respiring cells)

partial pressure

the portion of the total pressure exerted by a gas in a mixture of gases

• a gas always diffuses from an area where its partial pressure is high to where its partial pressure is lower

postsynaptic cells

cells that receive signals from other neurons or cells through a synapse

processes signals into electrical and biochemical changes

presynaptic cells

neurons that send information to other neurons through a synapse

quickly releases chemical neurotransmitters in response to electrical impulses, or action potentials

the neurotransmitter is diffused across the space

primates

evolved from a lineage of small, arboreal, insectivorous eutherians

• 2 clades: wet-nosed primates (lemurs lorises, galagos) restricted to Africa, Madagascar, and tropical Asia; dry-nosed primates (tarsiers, Ole World monkeys, New World monkeys, apes)

• Asian apes (gibbon, orangutan), African apes (gorilla, chimpanzee), and humans are modern descendants of Old World monkeys

• became hominin clade

• had bipedal locomotion

• in the homo lineage, brain size increased while jaw muscles decreased in size

radial and spiral cleavage

seen in eggs with little yolk and complete cleavage

rotational cleavage

at the 2nd division, blastomeres divide in different planes

sarcoplasmic reticulum

surrounds every muscle fiber

role: stores calcium ions and releases them into the sarcoplasm for the generation of action potential during muscle contraction

sequence of blood flow (human circulatory system)

1. oxygen-poor blood enters heart through superior and inferior vena cava

2. blood moves to right atria, then right ventricle

3. blood is pumped into lungs through pulmonary artery

4. oxygen-rich blood returns to heart through pulmonary veins

5. blood moves to the left atria, then left ventricle

6. blood is pumped to body through aorta

skeletal muscle

the type attached to the bones of the skeleton and provides power for walking, flying, swimming, etc.

• skeletal muscles appear striated due to the arrangement of actin and myosin filaments within the muscle fibers (sarcomeres)

Spemann experiment

a series of graftings in which some cells were removed from the dorsal side of an amphibian embryo and then transplanted to the other side of a second embryo

the transplanted dorsal cells caused the embryo to develop a second set of complete body structures

stroke volume

volume of blood pumped per heartbeat

synaptic plasticity

synapses can undergo long-term changes in functional properties and physical shape during an individual’s lifetime

titin

the largest protein in the body, runs the full length of the sarcomere

each titin molecule runs between the M band and a Z line, directly through a myosin filament

tropomyosin

a protein twisted around each actin filament

role: prevents actin and myosin from interacting and causing the muscle to contract at the wrong time (blocks myosin binding sites)

troponin

molecules attached at intervals of tropomyosin

role: sarcomeric Ca2+ regulator and helps trigger muscle contraction

ventilation

bulk flow of air or water between the gas exchange membrane and the outside world

• tidal - air moves in and out the same passageways

• unidirectional - in animals with gills water moves in a one-way stream across gills

• blood O2 partial pressure also controls ventilation, but is not as influential as CO2