exam 2 Flashcards
1
Q
what is a special feature of plant’s architecture?
A
they are dynamic- always growing
2
Q
what does a seed contain?
A
embryo (root and shoot apical meristems, 1-2 cotyledons, stored food in endosperm or cotyledons)
3
Q
when does seed growth resume?
A
during germination
4
Q
how do seeds build their body?
A
in response to internal and external cues
5
Q
what is the first trigger for germination?
A
an external cue of receiving water (universal- all plants need water to grow)
6
Q
what are some additional cues that some plants need for germination?
A
light, fire, mechanical breakdown of the seed coat (scarification), or chilling (stratification)
7
Q
what is imbibition?
A
when the seed takes up water
8
Q
what does imbibition to?
A
activates the embryo and begins germination
9
Q
what hormone does the plant embryo produce?
A
gibberellic acid (or GA)
10
Q
what does the hormone GA (or gibberellic acid) do?
A
it diffuses throughout the seed and targets the aleurone- this triggers the release of alpha-amylase (an enzyme)
11
Q
what does the enzyme alpha-amylase do?
A
triggers the release of sugars from the endosperm (where starch is stored) and they go to the embryo (and seedling growth)
12
Q
how does GA cause aleurone cells to make alpha-amylase?
A
transcription factor binds to the promoter and kept in check by the repressor; the GA bings to the receptor and enters the nucleus; a complex removes repressor, and alpha-amylase is produced
13
Q
what are main roles of GA in growth and development?
A
stem elongation, stimulation of fruit enlargement, and germination
14
Q
what does GA counteract the effects of?
A
ABA (abscisic acid)
15
Q
what do plant hormones do?
A
regulate growth, coordinate physiological processes, mediate environmental responses, excitation
16
Q
True or False: Plant hormones can only work in the places they are produced.
A
False- they can work where they are formed as well as in other tissues and organs
17
Q
what does a hormones’ effect depend on?
A
concentration, location, and presence and concentration of other hormones
18
Q
who discovered the hormone auxin?
A
Charles Darwin and his son
19
Q
where is auxin produced?
A
the plant’s tip
20
Q
how does auxin move through a plant?
A
rootward to induce stem growth
21
Q
where is indole acetic acid (IAA) produced?
A
terminal bud
22
Q
what does IAA suppress?
A
axillary buds closest to tip (remove terminal bud, branches grow out)
23
Q
what promotes branch growth?
A
cytokinin
24
Q
what does the hormone cytokinin do?
A
shoot induction, axillary bud outgrowth, prevention of leaf death
25
what does the hormone abscisic acid do?
water stress response, stomata closing, dormancy (in seeds and winter buds)
26
what is abscisic acid similar to?
carotenoids
27
what is cytokinin similar to?
adenine
28
what does the hormone ethylene do?
fruit ripening, leaf death (breakdown of chlorophyll), and lead abscission (leaf falling off)
29
which plant hormone is a gas?
ethylene
30
what is an external cue for plants?
light
31
how is energy for photosynthesis converted to chemical energy?
absorption by chlorophyll
32
how do plants set their internal clock?
by using light
33
what is always required for seed germination?
light
34
what does blue light trigger?
phototropism
35
what is phototropin?
a pigment in plasma membrane that absorbs blue light, goes through a conformational change, and exposes an active kinase site; also mediates stomate opening in response to blue light
36
how can you determine what wavelength of light is most effective in driving a biological process?
expose plant to light of different wavelengths and observe its response
37
what is responsible for red light response in plants?
phytochrome
38
what does phytochrome do?
seed germination and control of flowering
39
what are the 2 interconvertible states of phytochrome?
Pr (inactive), Pfr (active)
40
what is the action of phytochrome?
Pfr (active) can enter nucleus- exposed kinase phosphorylates itself, other targets, and activates transcription factors; leads to GA biosynthesis, which triggers alpha-amylase production
41
what activates the genes for biosynthesis of GA?
Pfr (active phytochrome)
42
what does the first division in embryogenesis result in?
terminal cell and basal cell
43
what does the terminal cell turn into?
embryo
44
what does the basal cell turn into?
suspensor
45
what is the suspensor in a plant embryo?
conduit for nutrients
46
what are the 4 steps in embryogenesis?
embryo (globular stage) -> morphogenesis (layers form, apical meristems organized) -> growth (storage molecules accumulate) -> prepare for physiological independence
47
what is a plant's ovule?
a seed
48
what does the ovule in a plant contain?
embryo and endosperm
49
what is a seed coat?
covering on the ovule
50
what is a plant's ovary?
a fruit (ripened, mature ovary)
51
how does fruit develop?
as ovules develop into seeds, changes occur in ovary wall
52
how do fruits promote the dispersal of seeds?
fleshy fruits "pay" animals to move the seed, dry fruits use mechanical dispersal
53
what is dormancy?
has a very slow metabolism, and waits for good growing conditions (down to 10% water)
54
in an angiosperm, what is the male gametophyte?
pollen
55
in an angiosperm, what is the female gametophyte?
embryo sac
56
what are the components of a flower?
sepals, petals, stamen, pistils
57
what are sepals?
leaflike, protect flower bud while developing
58
what are petals?
attract pollinators and sometimes have sacs of sugars
59
what are stamen?
produces pollen
60
what is a pistil?
the most complex of the floral organs, usually at the very center and bears ovules
61
how are floral organs arranged?
in whorls
62
what are the steps of the angiosperm life cycle?
meiosis, gametophyte development, pollination, fertilization, embryo development, and seed formation
63
where are the cells located that undergo meiosis?
inside the ovule and anther
64
where are microspores?
anthers
65
how do microspores develop into pollen?
a diploid cell undergoes meiosis and produces 4 haploid cells, and all 4 develop into pollen
66
what does one pollen contain?
sperm and a tube nucleus
67
where are megaspores?
ovule
68
how do megaspores develop into an embryo sac?
a diploid cell undergoes meiosis and forms 4 haploid cells, and only 1 survives to develop into the sac
69
how many rounds of meiosis occur in developing the embryo sac?
3 rounds producing 7 cells
70
what are the components of the embryo sac?
eggs and the central cell (containing 2 nuclei)
71
what does the central cell turn into when pollinated?
endosperm
72
what is pollination?
transfer of pollen from anther to the stigma of the pistil
73
what are the 2 types of pollination?
targeted and non-targeted
74
what is targeted pollination?
less pollen is needed, but an animal must be attracted to flower
75
what type of pollination is used by 3/4 of angiosperms?
targeted pollination
76
what is non-targeted pollination?
copious amounts of pollen is needed, and it is transferred via wind and water
77
how does pollen growth occur?
it lands on a compatible stigma and forms a pollen tube to carry nonmotile sperm to the ovule
78
how is the growth of the pollen tube directed?
by gene expression in the tube nucleus
79
most flowers are hermaphroditic, meaning what?
they contain both sexes, meaning they can self-pollinate
80
what is a downside to self-pollination?
inbreeding, as it can lead to an accumulation of genetic defects
81
what is outcrossing?
process that prevents self-pollination
82
how do plants conduct outcrossing?
animal pollination, different timing of pistil and stamen maturity, unisexual flowers, and self-incompatibility
83
what is monoecy?
both male and female flowers on one plant
84
what is dioecy?
separate male and female plants
85
what is self-incompatibility?
if the pollen is too similar to the ovule DNA, fertilization is blocked
86
if pollen is recognized at stigma as being compatible, what happens?
it forms a pollen tube, grows through the style, and reaches ovules to release sperm into embryo sac and then germinates
87
what is double fertilization?
2 sperm are in each pollen- one fuses with the egg forming a zygote, and one fuses with the central cell forming the endosperm
88
what is the beginning of the new sporophyte generation?
zygote --> embryo
89
what ploidy is the endosperm?
triploid (1N from sperm, 1N + 1N from 2 polar nuclei in central cell)
90
what plants experience double fertilization?
only angiosperms
91
what is the endosperm?
nutritive tissue that persists until germination unless consumed earlier
92
what is embryogenesis in plants?
an early period when a plant is contained within and is nutritionally dependent on maternal tissues
93
what type of growth occurs first in plants?
vegetative
94
the SAM forms ______ organs, then _____ organs.
vegetative; reproductive
95
True or False: Flowering influences how long a plant lives
True
96
what are perennial plants?
plants that flower year after year
97
what are annual plants?
plants that complete their life cycle in one year
98
what are biennial plants?
plants that complete their life cycle in two years
99
what do biennials require before they flower?
a chilling period
100
what makes the SAM switch from vegetative to reproductive growth?
internal cues (in all plants) and external cues (in many plants)
101
what are internal cues that trigger the switch to reproductive growth?
maturation of "phase change"
102
what are external cues that trigger the switch to reproductive growth?
day length (photoperiodism) and chilling (vernalization)
103
what is characteristic of a plant phase change?
the seed germinates and it is incapable of flowering (juvenile); after some period of growth it gains the ability to flower (adult)
104
what are advantages of the juvenile phase?
flowering is expensive, the flower could build up resources needed to successfully complete flowering and seed production
105
what are characteristics of the photoperiod in plant reproductive growth?
seasonal variation in flower production, temperature and water variability, and day length
106
what are short day plants?
they flower when days are short
107
what are long day plants?
they flower under long days
108
that are day neutral plants?
day length does not affect flowering time
109
what is the critical daylength?
a threshold that must be reached (days must be shorter than it for short day plants to flower, and longer than it for long day plants to flower); differs based on species
110
what organ perceives photoperiod?
the leaves
111
what are general characteristics of an animal?
multicellularity, heterotrophic metabolism, internal digestion, movement, nervous systems, lack cell walls, specialized cell junctions, conserved HOX genes
112
what do animals need to survive?
eat nutrients, take in oxygen, expel wastes, protect themselves, grow, reproduce, etc.
113
what is the closest outgroup of all animals?
colony of choanoflagellate protists
114
what are components of animal body plans?
symmetry, digestive system, coelom (body cavity), segmentation, appendages, and a nervous system
115
what are the 3 types of symmetry?
spherical, radial, and bilateral
116
what is spherical symmetry?
there is a single point from which any plant that bisects it results in similar halves (no apparent top/bottom)
117
what is radial/bilateral symmetry?
there is an anterior/posterior (anterior end typically the mouth)
118
what are 3 characteristics of bilateral symmetry?
true dorsal/ventral, right/left, and greater mobility on land
119
what are the 2 types of digestive systems?
sac design and tube
120
what is a sac design digestive system?
only one opening for both eating food and waste excretion; circulation, gas exchange, hydrostatic skeleton
121
what do sac design digestive systems lack?
specializations for ingestion/regurgitation, and organs for specialized digestion/absorption
122
what do organisms with sac digestive systems look like?
they remain small and thin
123
what is a tube digestive system?
a gut and 2 openings: mouth (eating) and anus (excreting)
124
what else is the tube digestive system used for other than digestion?
gas exchange across gut
125
what are tube digestive systems associated with, size-wise?
more complex forms and greater size and thickness
126
what is a coelom?
a body cavity
127
what are acoelomates?
no coelom (filled with masses of cells) and often lack complex organs; move by beating cilia
128
acoelomates sometimes refers only to _____blastic organisms, but often used for _____blastic organisms too.
triploblastic; diploblastic
129
what are pseudocoelomates?
have an interior sterile cavity that is not completely enclosed by the mesoderm; cavity is fluid-filled
130
why do we care what an organism has in their body cavity?
movement
131
what does segmentation allow for?
specialization of body regions that help changes in body shape
132
changes in segmentation can often result from what?
changes in the expression of Hox genes
133
what allowed the radiation of arthropods?
changes in segmentation
134
what are types of appendages?
feet, hands, and antennae
135
what does the nervous system do?
it allows for the coordination of movement and processes sensory inputs
136
what is a nerve net?
no central processing center, but can sense, relay, and react
137
what is a simple "brain"?
ganglia at the head end for integration and more complex actions
138
what is adherence of cells?
cells in an animal are arranged into tissues (cells must be able to stick to each other and to the extracellular matrix for tissues to be successful
139
what evolved to allow cells to "stick"?
cell adhesion molecules (CAMs) and integrins
140
what do integrins do?
attach cell cytoskeleton to collagen and other proteins in the extracellular matrix; it is often rearranged during cellular movement
141
what happens when integrin's 3D structure changes?
it cannot bind to the extracellular matrix- the cell detaches
142
what are 3 types of animal cell junctions?
tight junctions, desmosomes, gap junctions
143
what are tight junctions?
prevent materials in extracellular matrix from leaking between the cells and proteins in the plasma membranes from migrating to other side of cell
144
what are desmosomes?
binds cells tightly but does not prevent movement of material between cells or within the cells' membranes
145
what are gap junctions?
pores which flow adjacent cells to exchange material
146
what are the 4 animal tissue types?
epithelial, muscle, connective, nervous
147
what does epithelial tissue do?
barriers, exchange (secretion/absorption), storage, communication (chemical signal), reproduction, coordination
148
what are the 3 types of muscle?
skeletal, cardiac, smooth
149
what is characteristic of skeletal muscle?
multinucleate, striated, voluntary, fast
150
what is characteristic of cardiac muscle?
cells coordinated by gap junctions, some striations, myogenic, and rhythmic
151
what is characteristic of smooth muscle?
some tissues coordinated by gap junctions, while others not; not striated, many regulated unconsciously by enteric nervous system, involuntary and slow
152
what types of muscle is involuntary?
cardiac and smooth
153
what is connective tissue?
typically has fewer cells and more solid/liquid extracellular matrix, often with protein fibers like collagen and elastin in matrix
154
what are the types of connective tissue?
adipose (fat), cartilage, bone, and blood
155
what do neurons do?
fast electrochemical communication, sensory and communication
156
what are organs?
2+ different tissue types arranged spatially to perform a particular function or a particular set of functions
157
what is an organ system?
individual organs are usually part of a system that works together for a particular function
158
what is cephalization?
concentration of sensory organs and nervous tissues at the anterior end
159
why is an organisms motion important?
finding a mate, acquiring food, avoid predators, finding a suitable habitat
160
what was the major split in primate phylogeny 90 million years ago?
wet nosed and dry nosed primates
161
what was the split in primate phylogeny 35 million years ago?
apes and old world monkeys
162
when did humans split from orangutans?
~22 million years ago
163
what is characteristic of hominin phylogeny?
bipedal locomotion (the ability to walk on 2 legs)
164
what is characteristic of a bipedal primate?
a larger bicondylar angle
165
what do muscles do?
they interact to develop forces to move (they are the basis for behaviors)
166
what makes up ~1/2 of our body mass?
muscles
167
what are skeletal muscles?
throughout the body; muscles attached by tendons to bones, packed with actin and myosin
168
what are cardiac muscles?
in the heart; shorter muscle cells that are branched and in an interlinked network
169
what are smooth muscles?
in excretory system and blood vessels; loose network of actin and myosin (no bundles)
170
what is the function of skeletal muscle?
locomotion- movement of body parts
171
what is the function of cardiac muscle?
pumping blood within circulatory system
172
what is the function of smooth muscle?
movement of internal organs
173
what is a contraction?
development of force in a muscle (not always shortening)
174
what is the sliding-filament theory?
during contraction, small filaments seem to slide past each other
175
what is the structure of a skeletal muscle
clusters of myofibrils make up a muscle fiber, and clusters of muscle fibers make up a muscle
176
what is the z line in a muscle?
the ends of each sarcomere
177
what is the H zone?
the area between the actin and myosin filaments (contains the M line)
178
what is the A band?
the entire length of myosin in one sarcomere
179
what is the I band?
the area between the myosin filaments (contains the Z line)
180
what is a muscle fiber?
a muscle cell
181
what is actin?
a contractile protein in a muscle fiber; filaments are organized and thin
182
what is myosin in the muscle?
a contractile protein in a muscle fiber; filaments are organized and thick
183
what are myofibrils?
long, longitudinally oriented internal component of a muscle fiber made of actin and myosin
184
what is a sarcomere?
contractile unit of muscle cells; repeating units of myofibril
185
what is titin?
molecules of a protein that hold together the thick myosin filaments and returns the sarcomere to shorter length after stretching
186
what is tropomyosin?
protein that twists around each actin chain that controls interactions between actin and myosin; blocks or unblocks myosin-binding sites
187
what is troponin?
protein molecules that are attached to tropomyosin that help control position of tropomyosin; plays a role in controlling actin and myosin
188
what are cross-bridges in muscles?
bridge-like links between actin and myosin filaments, connected by myosin heads
189
what does it mean that a skeletal muscle fiber is "innervated"?
a nerve provides it a neural input
190
what is a neuromuscular junction?
a synapse where a motor neuron axon makes contact with a muscle fiber
191
what is excitation?
when a nerve impulse arrives at a neuromuscular junction and initiates an action potential
192
what is excitation-contraction coupling?
a process where electrical excitation of membrane leads to contractile activity by proteins
193
what is a transverse tubule (T tubule)?
indentations of the cell membrane at regular intervals over the surface of the muscle cell that conduct electrical excitation into the cell's interior
194
what is the sarcoplasmic reticulum?
endoplasmic reticulum of a muscle cell that is used for Ca2+ storage and release
195
how is a muscle contraction conducted?
Ca2+ is released from sarcoplasmic reticulum, which binds troponin and exposes myosin-binding sites on actin, allowing myosin to bind to actin and a power stroke begins
196
after a power stroke, how does a muscle contraction end?
ATP binds to the myosin head which unbinds it from the actin, and then the ATP is hydrolyzed and releases energy from myosin
197
what is the endoskeleton?
skeleton inside other tissues
198
what is the exoskeleton?
skeleton encases the rest of the body
199
what is bone?
made of extracellular matrix of collagen crystals among them
200
what is cartilage?
a flexible skeletal tissue that gives flexibility
201
what are joints?
the place where bones and muscles work together
202
what are tendons?
flexible connective tissue that attach muscles to bones
203
what is an antagonistic pair?
muscles that work together in opposite actions (one contracts, the other relaxes)
204
in a fish, where are the swimming muscles located?
the middle of the body, but they connect to the tail via tendons so only the tail moves during swimming
205
what are slow oxidative cells in fish?
slow-twitch cells that are red
206
what are fast glycolytic cells in fish?
fast-twitch cells that are white
207
how are exoskeleton muscles different from endoskeletal muscles?
they pull on the interior surface (on the apodeme, which is a part of exoskeleton that projects inside of the body in which muscles attach to)
208
what is a hydrostatic skeleton?
when a part or the whole body can become stiff like a skeleton due to a high fluid pressure inside
209
what is power, in relation to muscles?
the rate at which work is done
210
what is an oxidative system?
production of ATP by aerobic metabolism ramps up in the first minute and can be indefinitely sustained (citric acid cycle and e- transport)
211
what is a glycolytic system?
anaerobic glycolysis accelerates its synthesis of ATP to its peak rate within seconds, but is self limiting
212
what is an immediate system?
performed ATP is immediately available but quickly exhausted
213
what is endurance exercise?
steady, long-duration exercise
214
what is resistance exercise?
generates large forces in a few repetitions of movement in a short time
215
what type of muscle cells are more common in a long distance runner?
slow oxidative cells
216
what type of muscle cells are more common in a sprinter?
fast glycolytic cell
217
what are slow-twitch fibers better adapted for?
sustained aerobic activity
218
what are fast-twitch fibers better adapted for?
generating maximum tension quickly, but also fatiguing quickly
219
what type of muscle cell has a lot of mitochondria?
slow-twitch fiber
220
what type of muscle cell has few mitochondria?
fast-twitch fiber
221
in which type of muscle fiber is partial contraction possible?
slow-twitch fiber
222
what is the source of ATP in fast-twitch fibers?
fermentation
223
what is the source of ATP in slow-twitch fibers?
aerobic respiration
224
how much does genetics explain the difference in muscle performance?
2-3%
225
what is involuntary movement?
contraction and relaxation of internal muscles
226
how many nuclei are in one skeletal muscle fiber?
many
227
how many nuclei are in one cardiac muscle fiber?
one
228
True or False: Cardiac muscle is not striated.
False- actin and myosin filaments are arranged in patterns in sarcomeres
229
what are intercalated discs?
the location where two cardiac muscle cells are connected (gap junctions)
230
what is the general shape of one smooth muscle cell?
spindle-shaped
231
how many nuclei are in one smooth muscle fiber?
one
232
are there striations in smooth muscle?
no (actin and myosin aren't in the same pattern)
233
what controls smooth muscle?
the autonomic nervous system
234
what are asynchronous flight muscles?
each excitation causes many contractions in invertebrate muscles
235
what is a catch muscle?
adductor muscles able to sustain contraction forces that close the 2 sides of the shell together in invertebrates (ex: clams)
236
where is most of the water in mammals?
inside cells
237
what is the purpose of extracellular fluid?
gives cells nutrients and removes cellular wastes
238
what is the definition of homeostasis?
the stability of the internal environment of an individual, such as a constant body temp and the physiological or behavioral feedback responses that maintain that stability
239
what is Walter Cannon's definition of homeostasis?
the coordinated physiological processes which maintain most of the constant states in the organism
240
what are 2 general approaches of homeostasis?
conformation and regulation
241
how is heat exchange regulated in the skin?
blood vessels constrict or dilate depending on the temperature
242
what happens to blood vessels near the surface when it is too cold?
they constrict
243
what happens to blood vessels near the surface when it is too hot?
they dilate
244
what are a few parameters of homeostasis?
thermoregulation*, pH, blood glucose, behavioral feedback responses, [O2], [CO2], [Na+], blood pressure, heartbeat, body fluids, etc.
245
why is homeostasis important for an organism?
organisms need to maintain stable environments inside because its likely that they live in a different type of environment, requiring some work or energy (or physical mechanism) to keep stability
246
why is thermoregulation important?
temperature affects rates of enzyme catalyzed reactions, and effects of these reactions vary so coordinating the metabolism at different temps is challenging
247
what is the Q10 temperature coefficient?
a measure of sensitivity of a reaction or physiological process to a change in temp (within a limited range)
248
what is a homeotherm?
an animal that keeps a steady internal body temperature
249
what are examples of homeotherms?
birds and mammals
250
what types of animals are regulators (in terms of temp)?
regulators
251
what are poikilotherms?
animals that vary their body temperature along with the environment
252
what are examples of poikilotherms?
frogs, lizards, fish (most aquatic animals)
253
what types of animals are conformers (in terms of temp)?
poikilotherms
254
what type of animal has a higher metabolic rate, no matter the external temperature?
homeotherms
255
which type of animal can survive in extreme temperature environments?
homeotherms and poikilotherms
256
how can reindeer survive in extreme environments?
they have a natural insulation- thick fur and hollow hairs full of nonmoving air
257
what is an endotherm?
an animal that gets heat primarily from internal sources (metabolism)
258
what type of animal tries to maintain constant temps- endotherms or ectotherms?
endotherms
259
what is an ectotherm?
an animal that obtains heat primarily from external sources
260
what type of animal can have higher or lower body temps than normal- endotherms or ectotherms?
ectotherms
261
what type of animal often have membranes that leak ions more often?
endotherms
262
why do endotherms often have membranes that leak ions?
to maintain ion gradients they spend more energy, and have higher metabolic rates and generate more heat
263
what types of adipose tissue is found in homeotherms?
brown and white adipose tissue
264
what type of adipose tissue produces heat?
brown adipose tissue
265
what is nonshivering thermogenesis?
when an animal produces heat without needing to expend more energy from shivering
266
what is a behavioral strategy that allows small animals to keep warm?
protective microenvironments
267
what are animals that try to maintain parameters at optimal levels?
regulators
268
what are animals that, for at least some parameters, allow the internal level to vary with the environment?
conformers
269
what is often lethal for conformers?
extreme environmental changes
270
True or False: All parameters will vary drastically in each organism.
False- some parameters are more important to keep constant, and others don't change much in the environment so they don't change much in the organism
271
True or False: There are different degrees of homeostasis.
True
272
what is the difference between acclimatization and acclimation?
acclimation- adjustments to lab-based environments or adjustments after prior exposure
acclimatization- adjustments to natural environments/seasonality
273
what is regional hypothermia?
one localized area on an animal can be cold while the remaining parts of the body stays warm
274
which type of animal can regulate their behavior- endotherms or ectotherms?
both endotherms and ectotherms
275
what is an example of temperature regulation?
lizards moving to a sunny rock
276
what is countercurrent flow used for in physiological acclimatization in Grant's Gazelle?
keeps the brain cool by 2-3 degrees Celsius
277
what is an example of physiological acclimatization?
sweating and panting releases heat by evaporation
278
what 4 ways can heat exchange occur?
radiation, convection, conduction, and evaporation
279
how does evaporation cool the body?
it comes off the body surfaces or breathing passages
280
what is radiation?
warmer objects lose heat to cooler objects
281
how is heat lost by convection?
a stream of wind is cooler than the body surface temp
282
what is conduction?
the direct transfer of heat when objects of different temps come into contact
283
why is a larger surface area an issue with heat loss?
more surface means more heat is usually lost, but it can also be gained
284
where is heat generated particularly in endotherms?
volume
285
what is hibernation?
a state with low body temps and thermal conformity
286
what types of animals hibernate (most often)?
small mammals
287
what are heterotherms?
homeothermic during summer, but hibernate in winter
288
how do bees thermoregulate?
the flight muscles keep the thorax warm; they collect water and spread it on the hive, then fan it to encourage evaporation
289
what likely drives adaptations for thermoregulation?
changes in DNA
290
what is a large difference between types of barracuda depending on the temperature they live in?
metabolic enzymes
291
why do we need to eat?
each cell in your body needs to break down and rebuild 2-3% of its protein molecules daily
292
how much ATP does each cell use daily?
10^14 ATP molecules
293
what are different types of feeding?
predation, suspension feeding, and symbiosis
294
what is suspension feeding?
an animal pulls in water and strains out the food
295
what is a food web?
map that shows the direction of energy flow through animal populations (who eats who)
296
what are the components of a homeostatic mechanism?
stressor, sensor with receptor, integrator, effector
297
what is a stressor in homeostasis?
causes deviation from a set point
298
what is a sensor with receptor in homeostasis?
detects the error signal produced by the deviation from the set point
299
what is an integrator in homeostasis?
receives info from sensor and sends compensatory signals to effectors
300
what is an effector in homeostasis?
produces changes to the internal environment
301
True or False: A homeostatic component can have one or more mechanistic role.
True
302
what is feedback?
info about the relationship between the set point of the system and its current state
303
what is feedforward?
feature of a regulatory system that changes a set point in anticipation (amplifies a response)
304
what is positive feedback?
type of control that acts to increase differences that arise between levels; speeds up an earlier process in a system
305
what is negative feedback?
type of control that acts to reduce differences that arise between levels; slows down a process
306
what type of feedback usually destabilizes a system?
positive feedback
307
what type of feedback usually stabilizes a system?
negative feedback
308
homeostasis does not have _______ feedback.
positive
309
when does feedback occur?
when the rate of an early process is affected by the amount of a later product
310
what is the homeostatic sensor in animals?
hypothalamus
311
what type of feedback is mammalian birth an example of?
positive feedback
312
what is a feedforward system?
organism reacts to stimulus that is not the end product of the pathway by changing downstream responses to the stimulus
313
what is an example of a feedforward system in plants and animals?
circadian rhythms
314
what is the central nervous system?
brain and spinal cord
315
what is the peripheral nervous system?
nerves in the rest of the body
316
what are spinal nerves?
nerves that come in pairs with one on each side of the body along the length of the spinal cord
317
what actions does the nervous system allow for?
sensing, integration, analyzation, homeostasis, motor
318
what are neurons?
cells of the nervous system that are small and elongated
319
what are nerves?
bundles of neurons (100s-10,000s)
320
what are sensory neurons?
neurons that carry signals from sense organs to the CNS
321
what are motor neurons?
neurons that carry signals to muscle
322
what is the pathway for sense integration?
sensing a stimulus at sensory organ --> CNS --> PNS --> muscle for response
323
how fast can mammal neurons transmit signals?
20-100 meters per second
324
what does a fast nervous system allow for?
the ability to quickly perform tasks
325
nervous systems are fast and & ______.
addressed (meaning go to a specific location)
326
what does it mean that neurons are excitable?
the cell membrane can generate and conduct impulses or action potentials
327
what is an action potential?
state of reversed polarity of the cell membrane
328
what does it mean when a cell can be depolarized?
when the electrical polarity is less negative
329
what is a membrane potential?
charge difference across the cell membrane
330
at rest, the inside of a cell membrane has a _____ charge.
negative
331
at rest, the outside of a cell membrane has a _____ charge.
negative
332
what is the resting membrane potential?
membrane potential when not firing an action potential when at rest
333
what separates the charges inside and outside a cell?
cell membrane
334
what produces an electrical potential in a cell?
charge imbalance across the membrane
335
what is the direction of propagation down a neuron?
from the cell body down to the postsynaptic terminals
336
what is a current in a neuron?
flow of electric charges from place to place
337
what is voltage in a neuron?
positive charges are connected in one place and negative charges are connected in a different place
338
what is the process of generation of an action potential?
Na+ enters cell, depolarizing portions of the membrane; Na+ voltage-gated channels nearby open when the membrane reaches a threshold needed for the AP to fire
339
what hyperpolarizes a neuron?
K+ voltage-gated channels open after the Na+ channels inactivate after a section of the axon is depolarized
340
how do action potentials jump along axons?
it starts at the beginning, then moves to the next node on the axon
341
what are the common anatomical features of neurons?
dendrites, cell body, axon, set of presynaptic axon terminals
342
what do dendrites do?
major site of synaptic input from other neurons
343
what does the cell body do of a neuron?
contains neuron's nucleus and organelles; integration
344
what is the axon hillock?
the spot where the cell body transitions to the axon, and is where a signal is integrated
345
what does the axon do?
propagates axon potentials over long distances to the axon terminals
346
what is a synapse?
junction that allows a neuron to communicate with its target cell
347
what does a presynaptic cell do?
conducts signals into the synapse
348
what does a postsynaptic cell do?
conducts signals away from the synapse
349
what is myelin?
concentric layers of the cell membrane wrapped around axons
350
what are some glial cells that act as myelin?
oligodendrocytes and schwann cells
351
what is white matter?
parts of nervous system with mostly myelinated axons (named for glistening white appearance)
352
what is the process of an action potential?
resting membrane potential becomes depolarization and leads to the peak of action potential, then the cell becomes repolarized and the resting membrane potential is restored
353
what are sensors in the nervous system?
sensory cells and sense organs
354
what are effectors in the nervous system?
cells or tissues that carry out orders from the control system
355
what are 3 types of neurons?
interneurons, afferent (sensory) neurons, efferent neurons
356
where are interneurons found?
neurons that are confined to CNS that connect other neurons together
357
what do interneurons do?
integration, command, and information-storage functions
358
what are the most abundant neurons in the CNS?
interneurons
359
what do afferent (sensory) neurons do?
carry signals from sensory cells to CNS
360
what do efferent neurons do?
convey signals from CNS to effectors (like muscles)
361
what are glial cells?
another cell type in the nervous system that is not excitable
362
what do glial cells do for the brain?
metabolic support for neurons, regulate extracellular fluid composition, and immune system
363
what do glial cells do during development?
guide growing neurons in CNS
364
what types of glial cells are in the CNS?
oligodendrocytes, astrocytes, and microglia
365
what is the most abundant cell in the brain?
astrocyte glial cells
366
what occurs at a chemical synapse?
neurotransmitter release and transmission that can excite or inhibit the postsynaptic cell
367
what is a neurotransmitter?
a chemical that can excite or inhibit a postsynaptic cell that is secreted at an axon terminal
368
what are common neurotransmitters?
acetylcholine (ACh), norepinephrine, dopamine, serotonin, GABA, glycine, nitric acid
369
is acetylcholine inhibitory or excitatory?
excitatory to vertebrate skeletal muscles; inhibitory at other sites
370
is norepinephrine inhibitory or excitatory?
both excitatory or inhibitory
371
is dopamine inhibitory or excitatory?
generally excitatory, but can be inhibitory
372
where does a neuron connect to a muscle?
neuromuscular junction
373
what channels are voltage-gated?
Na+, K+, and Ca2+
374
how does the muscle work in terms of sensory response?
receptor protein detects stimulus, and this results in an AP in the receptor's cell or results in release of a signal that eventually produces an AP in a neuron
375
what are sensory receptor cells?
cells (neurons) that transform energy of a stimulus into an electric signal
376
what is transduction?
a sensory receptor cell produces an electric signal from stimulus energy
377
what is characteristic of the cell membrane in a rod cell in the eye?
it is highly folded, allowing for more surface area for more photoreceptor molecules to be present
378
what is a sensory receptor protein?
membrane protein in sensory receptor cells that first detects a stimulus and produces a graded change in receptor cell's membrane potential
379
what is receptor potential?
graded change in membrane potential
380
what are the 2 receptor cell types?
ionotropic and metabotropic receptor cells
381
what is an ionotropic receptor cell?
a receptor protein that is a stimulus-gated Na+ channel
382
what is a metabotropic receptor cell?
receptor protein that activates a G-protein
383
what are mechanoreceptors?
cells that respond to mechanical distortion of their cell membrane, usually ionotropic
384
what are thermoreceptors?
cells that detect heat and cold, usually ionotropic
385
what are chemoreceptors?
cells that respond to presence or absence of specific chemicals
386
what is characteristic of moth olfactory cells?
they are highly specific and respond to 1 odorant
387
how does the auditory sense work?
sound pressure waves are alternating high and low pressures and the ear detects this
388
what kind of noises do high frequencies produce?
high pitch and notes
389
what kind of frequencies do low frequencies produce?
low pitch and notes
390
how does a sound wave move into and through the ear (steps)?
tympanic membrane, ossicles, oval window, cochlea, basilar membrane, organ of corti
391
what is the tympanic membrane?
part of the ear that vibrates when sound pressure waves travel through
392
what are the 3 ossicles in the ear?
stapes, incus, and malleus
393
what do the ossicles do?
transmit vibrations of tympanic membrane to oval window
394
what is the oval window?
where ossicles connect to the cochlea
395
what happens in the cochlea?
vibrations at oval window create pressure waves in the cochlear fluid
396
what is the basilar membrane?
when it is flexed, it bends stereocilia on hair cells in organ of Corti
397
what is transduced into APs in the auditory nerve?
movement of stereocilia
398
where are the lowest frequencies transduced on the basilar membrane?
at the apical end (the inside of the coil)
399
what do fibers in the membrane vibrate in response to?
different frequencies of sound/different pitches
400
what is the most simple function of visual systems?
sense and respond to light
401
what is a more complex function of visual systems?
more detailed images of the environment
402
what are photoreceptors?
sensory receptor cells that are light sensitive
403
what is a sensory receptor protein?
member of a family of closely similar membrane pigments- visual opsins
404
what is the cornea?
outer layer of the eye made of connective tissue
405
what is the pupil?
where light enters the light-sensing part of the eye
406
what is the iris?
small muscles that change diameter of pupil
407
what is the lens?
crystal clear proteins behind the iris
408
what is the retina?
space at the back of the eye with a photosensitive layer for focusing images
409
what is the pathway of light in the eye?
light enters eye, absorbed by rods and cones that send info to nuclei, of which converges on ganglion cells, which send. theAP to the brain
410
what are the layers of integrating neurons, from the back of the retina to the front?
photoreceptors (rods and cones), then bipolar cells (horizontal cells and amacrine cells), and then ganglion cells which axons combine to lead to the optic nerve
411
what are the types of photoreceptor cells?
rods and cones
412
which type of photoreceptor cell is responsible for color vision?
cones
413
True or False: Rods and cones produce APs just like neurons.
False- they do not produce APs but they make a graded membrane
414
what are compound eyes?
each eye has many optical units (ommatidia)
415
what type of organism have compound eyes?
arthropods
416
how can bats find prey and navigate?
sonar (sound echoes)
417
how do bats use sonar?
they use larynx (voice box) to make high frequency sound waves that bounce off surfaces
418
how do tiger moths "jam" bats echolocation?
produce bursts of ultrasonic sound at high intensity
419
what is a lateral line system?
a sensory organ that detects changes in pressure and movement in water
420
what types of sensory cells are ionotropic?
mechanoreceptor, thermoreceptor, and electroreceptor
421
what types of sensory cells are metabotropic?
chemoreceptor and photoreceptor
422
what are taste buds?
clusters of chemosensory receptor cells
423
what is centralization?
tendency for neurons to be clustered into centralized, integrating organs
424
what is cephalization?
trend toward increasing concentration of nervous tissue and sensory organs at the anterior end of an animal
425
what makes up the central nervous system?
large structures made mostly of integrating neurons and glial cells where most info processing, storage, and retrieval happens
426
what makes up the peripheral nercous system?
part of the nervous system that isn't the CNA, made of neurons and parts of them
427
what types of animals have simple nervous systems?
sea anemones and sea stars
428
what is the neuronal signaling pathway?
stimulus from sensory system enters PNS, CNS processing and integration of info, and the response is sent to effectors
429
what are the divisions of the autonomic nervous system?
enteric, sympathetic, and parasympathetic
430
what is the enteric division of the autonomic nervous system?
it is inside the gut wall and helps with digestion
431
where does the sympathetic division of the autonomic nervous system connect?
thoracic and lumbar spinal nerves
432
where does the parasympathetic division of the autonomic nervous system connect?
cranial and sacral nerves
433
what does the sympathetic division of the nervous system do?
immediate responses (fight or flight)
434
what does the parasympathetic division of the nervous system?
more restful responses (rest and digest)
435
what are spinal reflexes?
responses that don't use the brain and the signals come from the spine initiate motor neuronal signals in response to sensory neuronal signals in the spinal cord
436
what does the dorsal root of the spinal nerves do?
receive signals from sensory organs
437
what does the ventral root of the spinal nerves do?
sends signals out to the muscle
438
how is the body represented in the brain?
somatosensory and motor cortices in the brain
439
what is binocular vision?
2 eyes show overlapping visual fields (and how we can see objects in 3D)
440
what is the optic chiasm?
where the optic nerves meet
441
what is the cerebral cortex?
outermost layer of cerebral hemispheres, thin layer of cell bodies
442
what does the cerebellum do?
integrates sensory and motor info
443
what are the 3 divisions of vertebrate brain evolution?
forebrain, midbrain, and hindbrain
444
what does the forebrain become in development?
cerebrum
445
what does the hindbrain become in evolution?
pons, medulla, and cerebellum
446
what is the amygdala?
brain center responsible for emotion and memory of fear
447
what does ecstasy/MDMA do to the brain?
causes continual release of serotonin, causing cell overstimulation
448
what can ecstasy/MDMA do to the body?
rapid breathing/heart rate/BP/temp --> organ system failure --> death
449
what do addictive drugs trigger?
the release of dopamine (and can stop the uptake)
450
what does naloxone do?
blocks opioid receptors in CNS and periphery
451
what type of drug (Na+ or K+ blocker) prolongs the AP?
K+ blocker
452
what type of drug (Na+ or K+ blocker) decreases speed of conduction?
Na+ blocker
453
what type of drug (Na+ or K+ blocker) prolongs the refractory period?
K+ blocker
454
what type of drug (Na+ or K+ blocker) suppresses the ability to reach threshold?
Na+ blocker
455
what type of drug (Na+ or K+ blocker) increases the threshold?
Na+ blocker
456
what type of drug (Na+ or K+ blocker) prolongs repolarization?
K+ blocker
457
what is the path of oxygen in the respiratory system?
O2 enters lungs and crosses 2 simple epithelia, then goes into the blood and down to the muscle; then crosses epithelial wall into muscle cell, then into cytoplasm and enters mitochondria
458
how does dog ventilation work?
bulk flow ventilation
459
why do our cells need oxygen?
cell works to break down glucose and other food molecules to get energy for making ATP; electrons are released from food to oxygen
460
what are respiratory gases?
oxygen and carbon dioxide
461
how does air move?
bulk flow and diffusion
462
what is bulk flow?
flow of gases from one place to another, from an area of high pressure to low
463
what is diffusion?
particles move toward a state of equilibrium at random
464
what are the steps of alternation of bulk flow and diffusion?
breathing in oxygen (BF), oxygen does into lungs and blood (Diff.), circulation of blood (BF), oxygen out of capillary, into cell membrane, cytoplasm, then mitochondria (Diff.)
465
what are gas exchange membranes?
location where respiratory gases move between animals environment and thin internal tissues
466
what is breathing?
external respiration- moving oxygen in and carbon dioxide out of lungs
467
True or False: All animals need specialized breathing organs.
False- some can breathe through their skin
468
what is similar in the structure of gills and lungs?
tissue folding and branching
469
how is gill tissue folded?
folded outward (evaginated)
470
how is lung tissue branched?
folded inward (invaginated)
471
what is tidal airflow?
air flow changes direction in same air passage
472
what does unidirectional airflow?
airflow is in one direction in air passages
473
what are elements of specialized breathing organs?
ventilation system, thin gas exchange membranes with large surface area, high rate of blood perfusion
474
what is perfusion?
fast blood flow through capillaries or smaller blood vessels of a tissue
475
why do we need a fast rate of blood perfusion provided by circulatory system?
to get oxygen distributed quickly to cells
476
True or False: Diffusion happens faster in air than liquid.
True
477
what are the 2 gas exchange methods?
countercurrent and cocurrent
478
what is cocurrent gas exchange?
water and blood moves in the same direction
479
what is countercurrent gas exchange?
water and blood move in different directions
480
what kind of gas exchange is more efficient?
countercurrent gas exchange
481
what are systemic tissues?
non breathing organ tissues
482
what type of airflow do most vertebrates use?
tidal because there is nowhere else for the air to go
483
what type of airflow do most birds and crocodiles use?
unidirectional- rigid airways that don't change volume during inhalation/exhalation
484
how are airways distributed in insects?
they are throughout their bodies- gas filled invaginated tubules
485
what type of breathing system do insects have?
tracheal breathing system (gas-filled tubules)
486
what are internal gills?
gills within body chambers providing a covering for protection and prevents drying
487
what are external gills?
extend outside body, so no protection
488
what types of animals have no specialized breathing organs?
flatworms and sponges
489
what is the trachea?
windpipe that branches into 2 tubes, which further branches even more
490
what are alveolar sacs?
located at the end of each final branch and allows for a high surface area for gas exchange
491
what are conducting airways?
airways that are not directly involved in oxygen and carbon dioxide exchange
492
what are respiratory airways?
where oxygen and carbon dioxide are exchanged between air and blood via diffusion
493
what is tidal volume?
how much air can be moved in and out in a mammal's lung
494
what is the diaphragm?
muscle below lungs connected to ribcage
495
what are intercostal muscles?
muscles between ribs
496
what is exhalation?
elastic recoil of lung tissues (results in relaxed lung muscles)- breathe. out
497
what is inhalation?
muscles of diaphragm and some intercostal contract- breathe in
498
what part of breathing, inhalation or exhalation, is passive?
exhalation
499
what type of feedback control is breathing under?
negative-feedback
500
what would happen if we were somehow able to generate less carbon dioxide?
breathing would slow since it is negative-feedback
501
in rodent brains, where does the breathing rhythm originate?
pre-Botzinger complexes
502
in human brains, where does the breathing rhythm originate?
the medulla, but the entire brainstem is needed to breathe
503
what is the circulatory system?
a pump made of the heart, blood, and blood vessels
504
what does it mean for the circulatory system to be closed?
the blood is always contained
505
what does it mean for the circulatory system to be open?
the blood leaves the vessels into the body
506
what is the primary function of the circulatory system?
transportation of oxygen
507
what is the primary function of the circulatory system in insects?
nutrients
508
what types of animals have closed circulatory systems?
vertebrates, mollusks, and annelids
509
what are arteries?
large blood vessels that carry blood away from the heart
510
what are veins?
large blood vessels that carry blood toward the heart
511
what is the lumen in an artery?
the space in the center that allows blood flow
512
what is vascular endothelium?
simple epithelium that surrounds the lumen
513
what allows arteries to stretch and withstand high pressure?
the elastic tissue and smooth muscle
514
what is microcirculation?
beds of small blood vessels made of arterioles, capillaries, and venules
515
what systems is microcirculation not found?
open systems
516
what are capillary beds?
web-like structure or capillary network where oxygen and nutrient exhange occurs
517
how does exchange occur in capillaries?
pores (gaps) between endothelial cells
518
what is vasoconstriction?
contraction of muscles to make the lumen smaller
519
what is vasodilation?
relaxation of muscles to make lumen larger
520
what is the order of bloodflow?
heart --> arteriole --> capillary --> venule --> heart
521
what types of animals have open circulatory systems?
arthropods and most mollusks
522
what are the components of blood?
respiratory pigments (iron in human hemoglobin), plasma, red blood cells, white blood cells, and platelets
523
what are respiratory pigments?
proteins that help carry oxygen
524
what is the human respiratory pigment?
iron in hemoglobin
525
what is another respiratory pigment in other animals?
copper in hemocyanin
526
what is blood plasma?
solution in blood with no blood cells- made of water and other materials
527
what do platelets do?
blood clotting
528
what type of protein is hemoglobin?
a tetramer
529
what does it mean that hemoglobin is a tetramer?
each hemoglobin molecule can hold 4 oxygen molecules
530
what is myocardium?
muscle tissue in the heart
531
what is cardiac output?
volume of blood pumped per minute
532
what is stroke volume?
volume of blood pumped per beat
533
what is the breathing-organ circuit?
blood vessels that carry blood to and from breathing organ
534
what is the cardiac cycle?
cycle where the heart contracts and relaxes
535
what is blood pressure?
point when the pressure in the blood exceeds the pressure in the animal's environment
536
how is the heart's elecrical activity monitored?
EKG, or electrocardiogram
537
what is systole?
during each repetition of the cardiac cycle, period of contraction of the heart chambers
538
what is diastole?
portion of the cardiac cycle when the heart muscle relaxes
539
in an EKG, what does the P wave correspond to?
depolarization of atria
540
in an EKG, what does the QRS complex correspond to?
depolarization of the ventricles
541
in an EKG, what does the T wave correspond to?
repolarization of the ventricles
542
what is the atrioventricular (AV) node?
area of the heart where the signal is conducted to after the atria begin to contract (passes on signal to ventricle)
543
how is systolic measured via blood pressure?
no blood flow heard through artery at all
544
how is diastolic measured via blood pressure?
max pressure that allows continuous flow
545
what is the cardiovascular system composed of?
blood vessels and heart
546
what is a simple type of circulatory system?
single circuit- heart, gills, body, heart
547
what is a more complex type of circulatory system?
double circuit- heart, lungs, heart, body, heart
548
what circulatory system has evolved to be most similar to humans?
birds
549
what are critical characteristics of the circulatory system?
mean blood pressure, total cross-sectional area of blood vessels, and linear velocity of blood flow
550
when does blood pressure drop in the cardiac cycle?
after leaving the heart
551
where is the surface area highest in the cardiac system?
capillaries
552
where is the velocity highest in the cardiac system?
arteries
553
what do parallel arrays of blood vessels do?
creates large differences of temperature from place to place
554
what are autoregulatory mechanisms?
each tissue controls its own blood flow
555
what does regional autoregulation do?
sets up a problematic positive feedback loop, which can be counteracted by systemic regulatory mechanisms
556
what is atherosclerosis?
buildup of lipids in vessels
557
what does clotting do?
helps maintain homeostasis after an injury
558
what are the ways that animals can eat?
predation, suspension feeding, and symbiosis
559
what is a fluid feeder?
animal that eats liquids that contain organic molecules
560
what is a suspension feeder?
animal that ingests small organisms in water (such as bacteria)
561
what is a deposit feeder?
animal that picks up or scrapes food particles
562
what is a bulk feeder?
animal that eats another animal whole or in large parts
563
what are some main minerals we need in our diets?
calcium, phosphorus, potassium, sodium
564
what do we need calcium for?
bones
565
what do we need phosphorus for?
nucleic acids and ATP
566
what do we need potassium for?
nervous system
567
what do we need sodium for?
nervous system
568
why do we need energy?
to do work and maintain self and organization
569
what type of energy doesn't do any work?
heat
570
what is nutrition?
how animals ingest to meet their chemical substance and energy needs
571
what is an essential nutrient?
type of molecule that an animal requires but can't make by itself
572
what are some types of essential nutrients?
amino acids, fatty acids, vitamins, essential minerals
573
what vitamins are water soluble?
B1-12, Folic acid, and C
574
what vitamins are fat soluble?
A, D, E, K
575
what does a vitamin B3 (Niacin) deficiency cause?
pellagra, skin disorders, diarrhea, mental disorders
576
what does a vitamin C deficiency cause?
scurvy, slow healing, poor bone health
577
what happens when we don't get enough food?
the body starts to metabolize it's own molecules (self-consumption), which starts in the blood plasma; the fluid in the body shifts, leading to edema, starvation, and death
578
what is a metabolic rate?
amount of energy the animal converts to heat each day
579
what type of animals have a high need for oxygen?
homeotherms
580
how can you measure the energy cost of exercise?
measure the rate of oxygen consumption to the rate of heat production
581
what is the difference between the metabolic rate in humans and birds?
in humans, the faster you move increases the metabolic rate; in birds, slow and fast speeds have higher metabolic rates, while medium speeds have a low metabolic rate
582
what is basal metabolic rate?
standardized measure of metabolic rate
583
what is the general trend in animals' BMR?
smaller animals have a higher basal metabolic rate
584
what is a calorie?
the amount of heat required to raise the temp of 1 gram of water by 1 degree Celsius
585
what type of molecules can't be absorbed?
proteins
586
what does the mouth do?
chews food and produces an enzyme to start digesting carbohydrates
587
what does the liver do?
stores glucose as glycogen and releases glucose as needed, and synthesizes bile salts
588
what do the sphincter muscles do?
keeps food from entering or leaving midgut or stomach, except when it relaxes
589
what does the hindgut (colon/large intestine) do?
reabsorbs large quantities of water and minerals; forms and stores feces
590
what does the rectum do?
stores and expels fully formed feces
591
what does the esophagus do?
muscles undergo waves of contraction to move food to the stomach
592
what does the stomach do?
serves as a place for food to accumulate during a meal, and secretes HCl and protein-digesting enzymes
593
what does the pancreas do?
synthesizes digestive enzymes responsible for carbohydrate, lipid, and protein digestion; alpha and beta cells secrete insulin and glucagon
594
what type of pancreatic cells secrete glucagon?
alpha cells
595
what type of pancreatic cells secrete insulin?
beta cells
596
what does the midgut do?
principal location of food digestion and absorption by means of pancreatic digestive enzymes and liver bile emulsifying lipids
597
what is digestion?
breakdown of ingested food molecules into smaller chemical components that an animal is capable of absorbing and distributing to the tissues of the body
598
what are the functions of the digestive system?
digestion, absorption of nutrients, storage, and elimination of wastes
599
what makes up the foregut?
mouth, esophagus, and stomach
600
what makes up the midgut?
small intestine
601
at makes up the hindgut?
large intestine, rectum
602
what type of animals have tube gut systems?
bilaterians
603
what do canine teeth do?
ripping and tearing
604
what do incisor teeth do?
cutting
605
what do premolar teeth do?
shearing
606
what do molar teeth do?
grinding
607
what is the difference in intestine length between herbivores and carnivores?
herbivores have long intestines to store large amounts of plant material, and carnivores have short intestines
608
what is division of labor?
cells are specialized for a particular function
609
True or False: glucose and amino acids require a carrier protein to enter the cell through the membrane.
True- they are cotransported through the cell with Na+ ions
610
how is food processed through the digestive system?
mouth- salivary enzymes, stomach- acid and mechanical churning, intestine- small molecules and water absorption
611
where do proteins begin to be broken down?
the stomach
612
where do carbohydrates begin to get broken down?
the mouth (salivary amylase), then lumen of small intestine
613
where do lipids begin to get broken down?
the mouth (lingual lipase), then lumen of small intestine
614
what does the rumen do?
allows for cellulose digestion because of symbiotic relationship with microbes
615
what is released when blood glucose gets too high?
insulin
616
what is released when blood glucose gets too low?
glucagon
617
what can happen if there is too much glucose?
kidney, retina, and brain damage
618
why is the lac operon not always on?
it is energy expensive and because lactose is relatively rare sugar in nature
619
what is the lac operon?
genes encoding enzymes and other proteins needed for lactose metabolism are found clustered together with common promoter and regulatory sequences in an operon
620
what conditions are required for the lac operon to be expressed in high amounts?
lactose must be present, and glucose must be low
621
what causes the feedforward response of the lac operon?
lactose is present
622
what causes the feedback response of the lac operon?
glucose is low (because it is the end product of lactose metabolism)
623
what is the cause of type 2 diabetes?
insulin resistance
624
how many genes are shown to cause higher incidence of type 2 diabetes?
38+
625
what proves that type 2 diabetes is not genetic?
when looking at Pima groups, those in the US have a much higher rate of type 2 diabetes than those in Mexico
