BIOL240W Exam 1 Flashcards
1
Q
How do we know plants have evolved independently from a unicellular common ancestor?
A
Similarities are due to convergent evolution
Human physiology centers on systems, plants have similar functions but are more distributed throughout the body
2
Q
Advantages that both plants and animals have regarding moving onto land
A
Less competitive
More CO2
Environment rich in nutrients
Unfiltered sunlight
3
Q
Disadvantages that both plants and animals have regarding moving onto land
A
UV radiation, ozone layer
Water loss
Lack of support
4
Q
How did plants/animals respond to water loss disadvantage?
A
Plants had to form a waxy cuticle
Animals developed protective skin
5
Q
How did plants/animals respond to lack of support system?
A
Skeletal structures and vascularity
6
Q
Eukaryotes likely originated by endosymbiosis when
A
a prokaryotic cell engulfed a small cell that would evolve into a mitochondrion
7
Q
All eukaryotic cells have
A
mitochondria
8
Q
Vascularity
A
allowed plants on land to grow tall
Branches increased complexity, so more competition, so more evolution
9
Q
Key adaptations of plants when transitioning from land to water
A
A transport system and cuticle layer
10
Q
Homeostasis
A
tendency to resist change in order to maintain a stable, relatively constant internal environment
11
Q
Homeodynamics
A
a concept that describes how living systems maintain equilibrium while constantly changing
Relates to concentration gradients
12
Q
Complex biological systems are NOT ____ and require ________ __________
A
fixed, dynamic reguation
13
Q
General steps a living organism goes through to respond to a disruption in homeostasis
A
Stimulus-change detected-RECEPTOR-input sent via afferent-CONTROL CENTER-output sent via efferent-EFFECTOR-response to change
14
Q
Evolutionary adaptations enable more complex organisms to have
A
sufficient exchange with the environment via specialized surfaces that are extensively branched or folded
15
Q
Positive feedback mechanism
A
An effector continues to stimulate a sensor so that a greater change happens
does NOT maintain homeostasis
16
Q
Positive feedback mechanism example
A
Childbirth, nursing, blood coagulation
17
Q
Negative feedback mechanism
A
Move back towards steady state (homeostasis)
18
Q
Negative feedback mechanism example
A
Blood glucose, body temp
19
Q
Describe the blood glucose mechanism
A
Insulin when high, pancreas releases insulin
Glucagon when low, pancreas releases
20
Q
Body temp mechanism
A
Receptors:skin cells
Control center (brain) understands the stimulus
Effector causes change (sweating)
21
Q
Mice would spend less or more energy on thermoregulation than a larger animal?
A
more energy
22
Q
Water potential in plants is regulated by
A
negative feedback
23
Q
Nucleus
A
Contains genetic material (DNA)
Surrounded by nuclear membrane that helps regulate transport in/out of nucleus
24
Q
Mitochondria
A
For energy (ATP) production through cellular respiration
Have a small piece of circular DNA
25
Golgi apparatus
The organelle that modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles
26
Ribosomes
Molecular machines responsible for synthesizing proteins by translating mRNA
(made of proteins and RNA)
27
Endoplasmic reticulum
A network of membranes involved in protein and lipid synthesis. Can be rough or smooth
Location of translation (protein synthesis)
28
Cell membrane
A semi-permeable barrier that surrounds the cell, composed of a lipid bilayer with embedded proteins
29
Transport proteins
Proteins that assist in movement of substances across the cell membrane
30
Passive transport
The movement of substances across a cell membrane without the use of energy, including diffusion and facilitated diffusion
31
Active transport
The movement of substances against their conc gradient, requiring energy
Often involving pump protiens
32
Diffusion
The process by which molecules move from an area of high to low conc
33
Faciliated diffusion
A type of passive transport that uses transport proteins to move molecules across the cell membrane
34
Cell membrane structure
Hydrophobic head
Hydrophilic tails
Two layers of phospholipids
35
Hydrophobic
love nonpolar, not charged
36
Hydrophilic
love polar, water, charged
37
Small, polar molecules can
sneak through the core
38
O2 _____ easily, CO2_________ easiily
enters, leaves
39
Leak channels
Channel protein that is open all the time
40
Gated channels
Channel protein that is only open at certain times
41
Channel-mediated transport is an example of
facilitated diffusion
42
Facilitated diffusion depends on an _____, but active transport
existing energy gradient, makes the gradient
43
Protein pumps require what to function?
ATP
44
To warm up, the body
constricts blood vessels in extremities and decrease blood flow to skin (reduces heat loss)
45
To cool down, the body
dilates blood vessels in extremities and increases blood flow to skin (increases heat loss)
46
What body part regulates body heat?
Hypothalamus
47
Nervous system is made up of
nervous tissue
48
Integral membrane protein
Acts as channels, receptors, and transporters
49
Peripheral membrane protein
Signal transducers, facilitates interactions between cell and outside, surface association
50
Endocrine system is made of
glandular tissue (secretes something)
51
Neurotransmitters
electrical currents and chemical messages
52
Endocrine system is ________ than the nervous system
slower because it has indirect communication to target tissue
53
Why is the nervous system reactions so fast?
fast, direct communication to target tissue (hand/hotplate)
54
Neuron
nerve cell that transfer information within the body
55
What two types of signals do neurons use to communicate?
Electrical (long-distance)
Chemical (short-distance)
56
3 stages that nervous systems process information
Sensory receptor, brain and spinal cord in CNS, PNS to effector
57
Glial cells
insulate the axons of neurons
regulate extracellular fluid surrounding neurons
sometimes function in replenishing certain groups of neurons
58
Neurons make up
nervous tissue
59
3 characteristics of neurons
can be excited (create an electrical charge)
conductive (ability to propagate a signal)
secrete neurotransmitters
60
Neurons can translate an electrical signal into a
chemical signal
61
Cells can respond to stimuli from
environment OR other cells
62
Cell body (soma)
Contains one nucleus
63
Dendrites
short extensions off the cell body
site for receiving signals from other neurons
64
Axon
Extension away from the cell body
Some can be myelinated to improve conductivity
65
Synapse
Site of communication between neurons or between a neuron and target tissue
66
All neurons transmit electrical signals within the cell in
an identical manner
67
Connections made by active neurons are what distinguish the type of info being transmitted, how is this interpreted?
interpreting nerve impulses therefore involves sorting neuronal paths and connections
68
Processing of information takes place in simple clusters of neurons called __________ or the ________
ganglia, brain
69
no somas in the
spinal cord, only axons
70
Multipolar neuron
most abundant in the body
soma is at one end, dendrite at other end
Interneurons
71
Bipolar neuron
rare, special senses
only 2 processes extend from the body
soma is within the middle of the axon
Motor neurons ( sight, scent, hearing, taste)
72
Unipolar/pseudounipolar neuron
start as bipolar but develop into unipolar
mainly in PNS
Soma extends off the axon
Sensory neurons (skin, places that detect environment)
73
Interneurons
Conduct impulses within the CNS
Integrate sensory input or motor output
one of a chain of CNS neurons OR a single neuron connecting sensory/motor neurons
74
Motor neurons
Conduct impulses along efferent pathways from the CNS to an effector (muscle/gland)
75
Sensory neurons
Special sense organs
Conduct impulse along afferent pathways to CNS for interpretation
Ganglia of most cranial nerves
76
Neuroglia
Nervous tissue is made up of neurons and supporting cells called neuroglia
Neuroglia include oligodendrocytes, schwann cells, microglial, ependymal=
77
What role do oligodendrocytes and schwann cells play?
Myelination of axon
78
Nerve
collection of axons
79
Ganglion
collection of the cell bodies
80
Central nervous system
where integration takes place, brain and a nerve cord
81
Peripheral nervous system
carries information into and out of the CNS
Neurons of the PNS, when bundled together, form nerves
82
Chemical gradient
uneven distribution of molecules
83
electrical gradient
uneven distribution of charges
84
Movement of ions through protein channels will be driven by the chemical gradient and electrical gradient. Explain
Chemical (diffusion)
Electrical (attraction of repulsion of charges)
85
Resting membrane potential
-70mV
86
Change in membrane potential is called
action potential
87
The lipid bilayer membrane that surrounds a neuron is impermeable to ions because
ions must pass through ion channels (proteins) spanning the membrane
88
K+ wants to
exit the cell more
89
Na+ wants to
go into the cell
90
Inside the cell concentrations
High K+
Low Na+
91
Outside the cell concentrations
High Na+
Low K+
92
the ICF is
more negative than the ECF
93
ECF
extracellular fluid
94
Ligand-gated ion channel
Ion channels that change structure in response to a chemical binding to a receptor (ligand example: neurotransmitter)
95
3 main cellular events that contribute to the negative resting membrane potential of neurons
sodium potassium pump function, variable permeability of ions, anions trapped in the cell
96
Voltage-gated ion channel
Response to voltage changes
97
Charge inside cell minus charge outside cell
membrane potential
98
Gradient is maintained by sodium-potassium pump actively transports
Na+ outside the cell and K+ inside the cell
99
There are typically more K+ ________
leak channels than Na+ leak channels
100
Sodium potassium pump concentrations
3 sodium, 2 potassium
101
The cell is more permeable to
potassium
More K+ leaks out than the Na+ leaks in
102
Sensor
Primarily nerve cells with endings in your skin and brain
103
Control center
Location in an organism that processes information received from sensors
104
Effectors
Activated to oppose the stimulus that is causing the disruption to homeostasis
105
Evaporation of sweat leads to cooling of the body surface. This is an example of
negative feedback regulation
106
Plants and animals underwent major evolutionary changes to make the move to land but some of these changes have similarities. However, these changes were made independently of each other. This concept is called
convergent evolution
107
As is with regulating temp in humans, water potential in plants is regulated by a signal transduction pathway and a negative feedback loop
True
108
Afferent neuron
sensory neurons that carry nerve impulses from the sensory stimuli towards the CNS and brain
109
Efferent neuron
motor neurons that carry neural impulses away from the CNS and towards muscle to cause movement
110
An action potential travels from
axon hillock to axon terminal
111
Ventral root
Helps to transmit information from the spinal cord to the extremities of the body
112
The soma of pseudounipolar neurons is found in the
dorsal root ganglion
113
Signals being transmitted by neurons in a circuit enter the spinal cord via the
dorsal root and exit the spinal cord via the ventral root
114
Ogliodendrocytes are primarily located in the
white matter of the brain and spinal cord
115
Rules of ion movement in establishing the membrane potential
Ions move from high to low conc
Ions also move away from like charges and towards opposite charges
Depends on the permeability of the membrane
116
Why did plants/animals move to land?
Oxygen was dropping in the water
117
Ectotherm
cold-blooded
118
Endotherm
warm blooded
119
All or none law
Must fully pass the threshold to have action potential
120
Sub-threshold stimuli will NOT produce an
action potential
121
Refractory period
Period when action potential CANNOT occur
Ion cannot respond to any other stimuli
122
Afferent and efferent neurons are located completely within the
PNS
123
ICF is more negative on the inside due to
Losing positively charged ions (K+) via leak channels is the number one way that ICF becomes neg
The constantly working Na+/K+ pump
Charged proteins and DNA (DNA in a cell is always in complex with proteins, DNA itself has a negative charge)
124
Opening of voltage gated ion channels in the plasma membrane converts
chemical potential to electrical potential and results in an action potential
125
Vesicle transport moves
down the axon to the synapse and uses microtubules
126
Secretion
Process of converting the electrical signal of the presynaptic neuron to a chemical signal in the synapse and then back to an electrical signal in the postsynaptic neuron
127
Describe the 4 steps of a chemical synapse
1) An action potential arrives, depolarizing the presynaptic membrane
2) The depolarization opens voltage-gated channels, triggering an influx of Ca2+
3) The elevated Ca+ conc causes synaptic vesicles to fuse with the presynaptic membrane, releasing neurotransmitter into the synaptic cleft
4) The neurotransmitter binds to ligand-gated ion channels in the postsynaptic membrane
128
When Na+ enters the cell, ICF
becomes more positive, then action potential fires
129
Summation
One component of integrations
Interneurons and motor neurons receiving information from multiple cells and then adding the change to determine if an action potential is initiated
130
Two categories of postsynaptic potentials
Excitatory -> Toward threshold of action potential
Inhibitory -> Moves membrane potential away from threshold
131
A single EPSP is usually too
small to trigger an action potential in a postsynaptic neuron
132
Depolarization of postsynaptic neuron
EPSP
133
Hyperpolarization of postsynaptic neuron
IPSP
