exam 4 Flashcards
locomotion
movement of an organism under its own
power
The cost of locomotion for running, flying, and
swimming animals decreases
with body mass
Vertebrate skeletal and cardiac muscle tissue is made of long, slender cells called
muscle fibers
Each muscle fiber has many threadlike, contractile structures called
myofibrils
myofibrils are striated due to alternating light-dark units
called
sarcomeres
sarcomeres shorten=
myofibrils contract
sarcomeres lengthen =
myofibrils relax
Muscle cells contain many ____, which contain
many sarcomeres
myofibrils
Sarcomere made up of two types of proteins: what are they and what do they do
- Actin: composes thin filaments
- Myosin: composes thick filaments
Thin actin filaments are composed of 2 coiled chains of actin:
One end is anchored to the Z disk, which forms the wall
between sarcomeres
* The other end is free to interact with thick filaments
z disk in thin actin filaments
forms the wall
between sarcomeres
contraction of sarcomere
The filaments slide past one another
- The sarcomere shortens with no change
in lengths of the thin and
thick filaments themselves
myosin’s “Head” binds ___ and actin
ATP
myosin head can bind to actin
head which
catalyzes hydrolysis of ATP
ATP binding releases
actin and myosin
rigor mortis
myosin and actin
locked together after an animal dies.
ATP required for myosin to release
actin.
step 1 of myosin and actin interaction
ATP binds to myosin head, causing conformation change, releasing head from actin.
step 2 of myosin and actin interaction
When ATP is hydrolyzed, myosin head pivots and binds to new actin subunit farther down thin filament
step 3 of myosin and actin interaction
When inorganic phosphate is released, head pivots back to original conformation. Power stroke moves entire thin filament relative to thick filament
step 4 of myosin and actin interaction
ADP is released, and myosin head is ready to bind to
another ATP
Thin filaments also contain proteins what are they and what do they regulate
troponin and tropomyosin. regulate muscle activity
also work together to block myosin binding
sites on actin
the 4 steps of myosin and actin interaction is called what
sliding filament model
classes of muscles
Multivariate vs. Univariate:
Multivariate = multiple nucleus
Univariate = single nucleus
classes of muscles
Striated versus unstriated
Striated = striped appreance (e.g., skeletal muscles)
Unstriated = smooth appreance (e.g., smooth)
smooth muscles characteristics
- tapered. thin sheets.
- Lack sarcomeres that are found in skeletal and
cardiac muscle, unstriated. UNIVARIATE. - Essential to function of lungs, blood vessels,
digestive system, urinary bladder, and
reproductive system
cardiac muscle characteristics
- make up walls of heart and responsible for pumping blood. have sarcomeres, striated, branched, connected end to end by intercalated discs.
- generate their own electricity
3.involuntary, spontaneous depolarization- do not require nerves
skeletal muscles
- unbranched, long, multiple nuclei, striped, packed with myofibrils, striated appearance
- attached to bones
- openings of the digestive system and urinary tracts.
damage to skeletal muscles will result in
paralysis
where is a plant getting its mass from
mostly CO2 since its transformed into sugar in photosynthesis
essential nutrient
element or compound required for normal growth and reproduction
Three elements make up 96% of the dry mass of the plant:
carbon
hydrogen
oxygen
macronutrients
plants need large quantities of macronutrients, certain elements, from the soil.
-Some are major components of nucleic acids, proteins, and
phospholipids (e.g., nitrogen, phosphorous, and potassium
micronutrients
plants require micronutrients in small
quantities
usually act as COFACTORS of specific enzymes
zone of maturation contains what
root hairs
how do root hairs absorb nutrients from the soil
electrochemical gradients created by proton pumps
what do root hairs do
provide tremendous surface area for nutrient absorption
how do cations enter root hairs
via channels
how do anions enter root hairs
cotransporters
Fungi and plant roots that live in symbiotic association are called
mycorrhizae
symbiotic relationship between plant and fungi is
mutualistic
fungi- obtain sugar from the plant
plant- receive nutrients from fungi- nitrogen
passive exclusion
root cells lack transporters to bring in toxic ions
active exclusion
plants have mechanisms for coping with toxins that enter their cells
plants exclude toxic ions by
passive and active exclusion
casparian strip blocks negative ions in what
passive exclusion
Metallothioneins and phytochelatins in active exclusion
synthesized by special enzymes
bind to metal ions and prevent them from acting as poison, macromolecules
epiphytic
plants appear to live inthe air
parasites
live on or inside a host in hopes to obtain water or nutrients from host and reduce their fitness
haustoria in heterotroph parasitic plants
penetrate host vascular system to obtain water and nutrients
most parasitic plants are ___ and use haustoria to extract ___ and ions from xylem of host plant
photosynthetic, water
epiphytes characteristic
non parasitic, grow in absence of soil, nutrietns absorbed through the leaves
carnivourous plants
trap insects and other animals. kill their prey and absorb their nutrients. make their own carbs from photosynthesis.
ex. venus fly trap- nitrogen from insect
The force output of skeletal muscle depends on:
) relative proportion of different fiber types
(2) organization of fibers within the muscle
(3) how the muscle is used
The length change of muscle is determined by
length of muscle
fibers or (2) how many sarcomeres
are lined up in a row in each fiber
the force of muscle is proportional
to
cross-sectional area of muscle
cell and (2) number of sarcomeres
lined upside by side, pulling in
synchrony
- Skeletal systems have four functions
Protection from physical and biological assaults
(2) Maintenance of body posture
(3) Re-extension of shortened muscles
(4) Transfer of muscle forces to other parts of body
All animals have one or more of three types of skeletal
systems:
hydrostatic, endoskeletons, exoskeletons
hydrostatic skeletons
use hydrostatic pressure of
enclosed body fluids or soft tissues to support body
endoskeleton vs exoskeleton
have rigid structures inside body
exo- outside
Hydrostatic skeletons: structure
Soft-bodied animals, body wall surrounds a fluid under compression, interior of animal has seawater, coelomic fluid, blood, or soft organs.
Antagonistic muscle groups
cause shape changes in
Hydrostatic Skeletons
-circumferential and longitudinal muscles
Alternating contractions of longitudinal and circumferential
muscles pass down earthworm in waves called
peristalsis
examples of endoskeleton
-Sponge endoskeletons
are made of silica to
provide structural
support
-Echinoderm
endoskeletons are
made of calcium
carbonate to provide
structural support.
endoskeleton structure composed of what
calcium carbonate
It is made of rigid levers
separated by joints—
vertebrates change their
shape largely by changing
joint angles rather than
body segments
vertebrate skeletons were composed of 3 main elements
bones, cartilage, ligaments
bones
have cells in a hard extracellular matrix:
* Bones interact at articulations or joints
cartilage
has cells scattered in a gelatinous matrix of
polysaccharides and protein fibers
ligaments
bands of fibrous connective tissue that binds bones to other bones
Bones attach to skeletal muscle via bands of fibrous connective
tissue called
tendons
Vertebrate skeletons move by changes in joint angles controlled by
antagonistic muscle groups:
flexors and extensors
flexors
pull bones closer together, decreasing joint angles (e.g.,
hamstring
extensors
increase the angle of a joint, straightening it out (e.g.,
quadriceps)
Endoskeletons move by contraction and relaxation
of
flexor and extensor muscles
endoskeleton function
calcium homeostasis
bones store calcium and other minerals
osteoblasts
bone-building cells that secrete protein and
calcium-rich extracellular matrix
osteoclasts
bone-resorbing cells that secrete acid onto bone
tissue when blood calcium levels are low to cause small amounts
of mineral to be resorbed into the blood
osteoporosis
disease in which reduced bone mass can make
bones brittle and susceptible to fracture
exoskeleton structure
exterior skeleton that encloses and protects an
animal’s body
insect exoskeleton
consists of
cuticle made up of proteins and chitin
Crustacean exoskeleton consists
of
cuticle mineralized with calcium carbonate
exoskeleton function
muscles packed within skeleton, must be shed for internal parts to grow, extensor muscles operate jointed skeletons
apodemes in exoskeleton
ingrowths where muscles are attached