ASSIGNMENTS UNIT 1-7 Flashcards
1
Q
Does the ozone layer prevents UV-A, UV-B to reach earth?
A
No, they reach earth. It blocks UV-C rays.
2
Q
What are Ommatidia’s?
A
The units of compound eyes in insects.
3
Q
What is required for bioluminescence?
A
Requires an energy input.
4
Q
Do viruses have their own metabolism?
A
No
5
Q
Which structure is not present in bacteria?
A
Mitochondria
6
Q
Do bacteria have an extensive endomembrane system?
A
No, they don’t have organelles or endomembrane systems like ER or Golgi.
7
Q
What do photoautotroph use?
A
Energy from sunlight and use inorganic molecules as carbon source.
8
Q
What supports the idea of evolution?
A
All organism have the same genetic code, all use ATP for energy, cells have membranes with lipid bilayer.
9
Q
When does the sun shine directly over the equator?
A
In march
10
Q
Do you need to use energy to increase entropy?
A
no
11
Q
What influences the performance of enzymes?
A
PH, temperature, activators, inhibitors.
12
Q
How is ATP used in most cell processes?
A
The hydrolysis of ATP is coupled to an endergonic reaction.
13
Q
How do enzyme function?
A
Lower the activation energy required, change the shape of the substrate, bring reactants together, expose substrate to negative/positive charges.
14
Q
Can enzymes be affected by temperature?
A
Yes
15
Q
When coupled to an endergonic reaction, ATP free energy is released as heat?
A
No
16
Q
What is osmosis?
A
Occurs across a membrane, special form of diffusion, only water flows, based on a concentration difference.
17
Q
Do channel protein requires energy?
A
No
18
Q
Are carrier proteins associated with facilitated diffusion?
A
Yes
19
Q
Process that can’t move water or particles into a cell.
A
Exocytosis
20
Q
Is active transport associated with exchange diffusion?
A
Yes
21
Q
Where does the Citric acid cycle take place?
A
Mitochondrial matrix
22
Q
is glycolysis associated with chemiosmosis?
A
no
23
Q
High proton concentration in intermembrane space of mitochondria comes from:
A
reactions in the electron transport chain
24
Q
What substances are involved in the regulation of aerobic respiration?
A
ATP, citrate, NADH, AMP
25
Without the light reactions, what is needed to proceed with the Calvin cycle?
ATP, NADPH
26
Is rubisco used in cam plants?
Yes
27
Does CAM plants used the calvin cycle?
yes
28
Which component is not crucial for cyclic electron transport in photosynthesis?
PS11
29
How many photons needs to be absorbed to produce two molecules of 02?
16
30
What is evolution?
gradual change of characteristics of a population over a long period of time which can be the result of selection All from one common ancestor,
31
What is selection?
individuals in a population have different inheritable traits and the population can produce a lot more offspring than what the environment can support, which causes competition to have access to the resources to survive. Some of these offspring have inherited traits that give them an advantage in their environment, which gives them more chances to survive and reproduce. They will then pass those favorable traits to their offspring and over time, the population will evolve by obtaining those traits.
32
What is an exergonic reaction?
Spontaneous, no need energy to start. The change in free energy is negative because the reactant has more free energy than the product. It also releases free energy to its surroundings.
33
What are the characteristics of photons?
They have no mass and a small amount of energy
34
How does bioluminescence work?
When an excited photon returns to its gound state.
35
Why can pigment molecules absorb light?
Because of their conjugated system where carbon atoms are alternating between single and double bond.
36
The 9+2 structure refers to?
It is the arrengement of the microtubules in structures such as the flagella and cilia of eukaryotes.
37
What is the most recent mechanism in evolutionary terms?
Aerobic respiration since oxygen was not present in the atmosphere before.
38
What is a structure that is not common to both eukaryotes and prokaryotes
The nucleiod
39
What term refers to an RNA world?
Ribozymes. Where one molecule could carry and catalyst the information.
40
Where are trade winds?
In the tropics. Also called easterlies
41
A population of bacteria that becomes resistant to antibiotics is an example of ?
Selection. Because the resisting strains are resistant and create more resistant progeny.
42
When does the sun shine directly over the equator?
During the March and September equinox
43
Chemoautotroph use what?
They oxidize molecules for their energy source and use CO2 as their carbon source.
44
What is not a function of the cell membrane:
- transmitting signals
- energy transfer
- permeable to all substances
- regulating the passage of materials
- participate in chemical reactions
C.it is selectively permeable
45
What does active membrane transport involve?
a. NADH.
b. diffusion.
c. movement against a concentration gradient.
d. exocytosis.
e. all of the above.
Diffusion.
Active membrane transport needs energy because it moves across the concentration gradient while diffusion doesn't need energy because it moves with the concentration gradient.
46
14. Which of the following terms relates to phagocytosis?
a. endocytosis
b. exocytosis
c. pinocytosis
d. cell drinking
e. all of the above
ENDOCYTOSIS. Where it brings materials into the cells with endocytic vesicules.
47
15. Aquaporins are
a. peripheral proteins.
b. phospholipids.
c. glycolipids.
d. carbohydrate groups.
e. integral proteins.
They are integral proteins that create a channel that only allows water in for the process of osmosis.
48
16. Which of the following terms does NOT refer to allosteric regulation?
a. feedback inhibition
b. competitive inhibition
c. allosteric activation
d. reversible inhibition
e. enzyme shape
Noncompetitive inhibition. Because allosteric inhibitors bind to sites different from the active site.
49
What is the substance on which an enzyme acts on?
A substrate. It converts it in different molecules (products).
50
18. Which of the following statements concerning activation energy is FALSE?
a. Catalysts raise a reaction’s activation energy.
b. Activation energy is the energy required to break existing bonds.
c. Endergonic reactions have an energy of activation.
d. Exergonic reactions have an energy of activation.
e. Enzymes lower a reaction’s activation energy.
CATALYSTS RAISE A REACTION ACTIVATION ENERGY.
| They actually lower the activation energy needed to start a reaction which speeds it up.
51
What is the change in an enzyme-catalyzed reaction when temperature increase?
It increases the rate of reaction, but if the temperature increases too high, the rate rapidly decreases because the enzyme becomes denaturated and can no longer function.
52
During chemiosmosis in the mitochondria, ATP is produced as?
As protons are pumped in the mitochondrial matrix by ATP synthase.
53
What is the immediate fate of the electrons in NADH during fermentation?
They are transferred to an organic molecule because NAD+ is needed to keep the glycolysis cycle going.
54
Which of the following statements about lactic acid fermentation is NOT correct?
a. It produces two ATP molecules for every glucose molecule.
b. It is inefficient compared to aerobic respiration.
c. Oxygen is the final electron acceptor of this pathway.
d. It uses glucose as a substrate.
e. Glycolysis is the only energy-yielding step of this pathway.
OXYGEN IS THE FINAL ELECTRON ACCEPTOR. It is anaerobic respiration, so no oxygen in there.
55
Which of the following steps in the citric acid cycle directly produces a molecule of GTP?
succinyl CoA → succinate
56
Why does red and blue light support the highest rates of photosynthesis?
Because chlorophyll preferably absorbs blue and red photons of light, while reflecting the green that it can't absorb.
57
What may happen AFTER an electron is induced by a photon?
The electron releases energy as heat as it moves back to ground level.
58
Which of the following applies to cyclic electron transport but does NOT to apply to non cyclic electron transport?
a. Protons are moved into the thylakoid lumen.
b. production of ATP, but not NADPH
c. production of both ATP and NADPH
d. photolysis
e. P680
PRODUCTION OF ATP BUT NOT NADPH.
59
Does chemiosmosis occur in photosynthesis and aerobic respiration?
Yes
60
Chlorophyll absorbs mostly which regions of the visible spectrum?
Blue and red, reflects the green because it can't absorb it.
61
What is an eye?
The organ animals use to sense light, it requires a nervous system to interpret the signals. The ocellus is the simplest for, it only sense light. Image capturing eyes: A compound eye contains hundreds of ommatidia (arthropods). Single-lens eyes, light enters eye through the cornea, and the retina records the image.
62
What is an eyespot?
It is located in the chloroplast and its photoreceptors allows it to sense the light direction and intensity.
63
What is uv radiation?
Ultraviolet radiation with wavelenghts between 200-400nm. Cannot be seen with the human eye. The ozone layer protects us from UV-C, but not UV-A, UV-B. It has high energy and can ionize atoms in molecules
64
What is light?
it is the portion of the electromagnetic spectrum that we can detect with our eyes. It is a narrow band of electromagnetic radiation of 400-700 nm.
65
What is an endergonic reaction?
A reaction that can only occur when free energy from the surroundings is supplied. The products have more free energy than the reactants. Does not really relate to the change in temperature of the reactants, but more to the spontaneity of the reaction.
66
What is an endothermic reaction?
A reaction that gains energy from its surrounding in the form of heat. The products have more free energy than the reactants.
67
What is competitive inhibition?
Because enzymes can reduce the activation energy of a reaction, making it happen quicker, enzyme inhibitors can bind to an enzyme to reduce the rate of the catalyzation of the reaction. In comp. inhibition, a comp. inhibitor that ressembles the substrate competes with it for the active site.
68
What is non-competitive inhibition?
Because enzymes can reduce the activation energy of a reaction, making it happen quicker, enzyme inhibitors can bind to an enzyme to reduce the rate of the catalyzation of the reaction. In non-comp. inhibition, the non. comp. inhibitor binds to a different place on the enzyme than the active site, causing a change of shape of the enzyme so that the normal substrate can't bind to the active site anymore.
69
What is the Golgi complex?
An organelle part of the of the endomembrane system in the cytoplasm of eukaryotes which receives the proteins and lipids from the ER, which job is to sort, distribute and provide final modifications to proteins and lipids, putting them in vesicles for their destination. Works with the ER to develop proteins and lipids.
70
What is the endoplasmic reticulum?
An organelle inside the cytoplasm of eukaryotes that form a series of flattened sacs. There are two types, the rough ER, smooth ER. The rough ER has ribosomes attached to its surface and synthesize proteins. It is responsible for the initial modification and the synthesis and transport of proteins and lipids. The smooth ER synthesize lipids.
71
What is substrate level phosphorylation?
Is a mode of ATP synthesis that requires an enzyme that transfers a phosphate group from a substrate molecule to ADP, which produces ATP. Used in glycolysis and in the citric acid cycle. It will only occur if a reaction producing enough energy to allow the direct phosphorylation of ADP is present.
72
What is oxidative phosphorylation?
A mode of ATP synthesis that is made through the oxidation of energy-rich molecules by an electron transport chain and chemiosmosis. It is the major source of ATP in aerobic organisms.
73
What is a C4 pathway?
It builds up high concentration of carbon dioxide in the chloroplast of the bundle sheath cells, that results in the increase the ration of carboxylation to oxygenation, minimizing photorespiration. Usually in dry and warm environment. The plant needs more energy to do this, but less than if photorespiration was happening. The enzyme PEP carboxylase is an essential enzyme in c4 because it doesn't use oxygen as a substrate.
74
What is the CAM pathway?
A method in which carbon dioxide is taken during the night and diffuse in the leave and combines with PEP carboxylase to form malate which is stored until daytime and then diffused and oxidized in pyruvate where the co2 is released in high amounts which activates rubisco allowing the Calvin cycle to proceed with little photorespiration.
75
What is glycolysis?
First step in cellular respiration. Has 10 steps that oxidizes glucose to two molecules of pyruvate. The potential energy released during the oxidation leads to the synthesis of NADH and ATP.
76
What is fermentation?
A way that a cell can oxidize fuel molecules and generate ATP without oxygen. Doesn't use an electron transport chain, instead it reduces pyruvate in the cytosol with NADH, producing NAD+ that can keep the glycolysis running producing ATP by substrate-level phosphorylation.
77
What is NADH?
Nicotinamide Adenine Dinucleotide, can be in two forms. Oxidized is NAD+ and reduced is NADH. It is involved in reddox reactions, which is carrying electrons from one reaction to the next. The potential energy that it carries is used to synthesize ATP.
78
What is ATP?
Adenosine Triphosphate is the main energy carrying molecule in cells because it can release it quickly. Once its energy is released, it becomes ADP which has low energy. It can be converted back by adding a phosphate.
79
What is photosystem I?
Is the second photosystem apparatus, with a centre of P700. When it absorbs a photon, P700* becomes excited and then oxidized P700+. It is reduced back to P700 by the electron given from PSII. The electron of P700 is transferred to ferodoxin to NADP+ which is then reduced to NADPH (non-cyclic phosphorylation). It can work independently from PSII by cyclic phosphorylation, instead of ferodoxin giving the electron to NADP+, it gives it back to the plastoquinone pool which is constantly oxidized and reduced, moving protons accros the membrane, which produces ATP without NADP+ to NADPH.
80
Why does PSI play an important role in photosynthesis?
Because it can do cyclic electron transport which is necessary since the calvin cycle needs more ATP than NADPH.
81
What is photosystem II?
Has a P680 centre, that absorbs light energy and become a P680* excited and then a P680+ oxidized by the primary electron receptor. The electrons are transferred to the plastoquinone pool and then to the cytochrome complex and to the plastocyanin carrier to PSI.
82
How rhodopsin work as a light receptor?
It is a photoreceptor where each molecule consist of an opsin protein that span the membrane and creates a complex with a pigment molecule retinal. When light is absorbed, the retinal change shape, which triggers the opsin protein which triggers changes in ion concentration and electric signals which allows the organism to process light reception.
83
What is the Milley-Uray experiment?
Proved that UV light with the conditions of a reduced atmosphere would lead to the building blocks for life. By adding the components of a reduced atmosphere in a close space and exposed them to sparkling electrode. This resulted in the creation of organic compounds in the water by spontaneous synthesization.
84
What is the term RNA world?
When we discovered ribozymes and figured that they could catalyze reactions on RNA strands and lead to their synthesis, the term RNA world means that early life maybe existed only with RNA since it can be the info carrier and the catalyst.
85
What is the relationship between surface area and volume of a cell for the two groups of organisms?
When the cell increase in size, its volume will increase more rapidly than its surface area. Prokaryotes have a larger surface area to volume ratio, which allows them to move waste and nutrients in and out. Eukaryotic cells are bigger but have a lower surface area to volume ratio because their process occur in the cell membrane.
86
What is a proton-motive force?
When there is a difference in the proton chemical gradient and electrical gradient across the membrane produces a proton-motive force which is stored energy.When cells use it to do work its called chemiosmosis. It happens when protons are transported from the inner to the intermembrane space. Because the innermembrane is impermeable to H+, the concentration becomes much higher there.
87
What are the advantages and disadvantages of having an aerobic metabolism?
It can produce a lot more of energy than anaerobic respiration. But because oxygen has oxidative properties ,when it is not reduced completely it forms ROS (reactive oxygen species) that can damage proteins, lipids and DNA, and that inevitable for all aerobic organisms. If the ROS levels are too high, the cell can die. Cells have enzymes that innactivates ROS as well as antioxidants that reduce them to water.
88
What happens after an electron absorbs light?
First, to be absorbed the energy of the photon must be the same as the energy difference of the electron ground to excited state. When they match, the photon will be absorbed and the electron fills with energy and becomes excited, containing the energy to do work. It can either return to the ground state and having a photon with less energy(fluorescence), or release energy as heat. Or return to ground state and transfer the energy by inductive resonance. Or the excited electron is accepted by the primary receptor which continues its way through PSII & PSI of photosynthesis.
89
What is the second law of thermodynamics and entropy?
1st law: Energy can't be created or destroyed but can be transformed.
2nd law: Every time energy is transferred, some energy is lost and can't do work, entropy of a system and its surroundings always increase.
Entropy is the disorder of the universe that is increased by the transformation of E and the loss of free energy.
Low entropy can be achieved bu energy is needed.
90
What is an exergonic reaction?
It is spontaneous and the reactants have more free energy than the products so free energy is released.
91
What is an exothermic reaction?
It releases energy in the form of heat or light because the product have more free energy than the reactants.
92
What is allosteric regulation?
Is a mechanism where enzyme activity is controlled by the reversible binding of a regulatory molecule to the allosteric site. It can either decrease or increase enzyme activity by having a high-affinity state or low affinity state. Allosteric inhibitors converts an enzyme from the high to the low affinity state and an allosteric activator converts an enzyme from the low to the high affinity state. Allosteric inhibitors are made from the metabolic pathway that they regulate so if there is too much product produced, the production of inhibitors increase, if too low products, prod of activator increase.
93
What is feedback inhibition?
Regulation where the product of a reaction act as a a regulator of it. If there is too much product produced, the production of allosteric inhibitors increase, if too low products, product of allosteric activator increase.
94
What are integral membrane proteins?
A type of membrane that is embedded in the phospholipid bilayer and most of them are transmembrane proteins having regions exposed to the regions of both sides of the membrane. The part of the protein in the core of the membrane is hydrophobic and can interact with the core. One of their function is to transport molecules across the membrane.
95
What is a peripheral membrane protein?
They are on the surface of the membrane and held temporarily by non-covalent bonds, and are hydrophilic on their surface so that they can attach and detach from the membrane at specific times. They are mostly on the cytoplasmic side and part of the cytoskeleton. They can be attachments for intracellular cytoskeleton and extracellular matrix and move molecules across the polar phospholipid bilayer.
96
What is a prokaryote?
Can be in the form of bacteria or archea and are 10 times smaller than eukaryotic cells and are more versatile. They have a nuclei in the cytosol instead of a nucleus, a plasma membrane
97
What is an eukaryote?
They have a nucleus and organelles like the mitochondria, ER, golgi complex.
98
What are enzymes?
They are proteins capable of speeding chemical reactions in the cell by lowering the kinetic barrier increasing the reaction rate and lowering the activation energy. Changes in PH, temp and concentration of substrate can change their activity.
99
What are ribozymes?
Are a group of RNA enzymes that catalyse them and lead to their own synthesis.
100
What is active membrane transport?
Uses pumps to push substances across a membrane against their concentration gradient. Require energy. Two kinds. In primary active transport, the protein doing the transport directly hydrolizes ATP to have the energy to move the molecule across, they only move positively charged ions. The pumps are calcium, protons, sodium-potassium. The sodium-potassium pumps create an electrochemical gradient across the membrane. In secondary active transport, the energy needed is from the gradient of the primary active transport, in symport, the solute moves through the membrane in the same direction of the ions, while in antiport, the ion moves through in one direction, providing energy to the molecule in the other direction.
101
What forms ADP?
Because ATP has an unstable chain of 3 phosphate group, the spontaneous removal of one releases lots of free energy and removes the repulsion between them, creating ADP.
102
What is alcohol fermentation?
Is a reaction where pyruvate is reduce to a molecule of CO2 and a molecule of ethyl alcohol as NADH is transformed to NAD+.
103
What is lactate fermentation?
When there is high demend for ATP and O2 can't keep up. Pyruvate is transformed in lactate in the cytosol of the cell.
104
What is fermentation?
When o2 supply is absent or almost absent. A series of reaction where the pyruvate stays in the cytosol and is reduced consuming the NADH and keeping NAD+ so that glycolysis can continue to produce ATP.
105
What is a light dependent reaction?
Is one phase of photosynthesis and involves the capture of light by pigment molecules and the use of energy to synthesize NADPH and ATP that will be used in the light independent reaction.
106
What is a light independent reaction?
Also called the Calvin cycle, use the NADPH and ATPP to reduce co2 in carbohydrate. It takes 3 turns of the cycle for the cell to produce one extra G3P that the cell can use as energy, to synthesize it 9ATP and 6NADPH are needed from the light-dependent reaction.
107
What is the theory of endosymbiosis?
Is that the mitochondria and chloroplast are descending from prokaryotes. That they were both free-living cells that ended up in a prokaryotic cell and instead of dying, it survived and integrated the host cell overtime. Because mitochondria were aerobic cells, it gave a big advantage to anaerobic cells when in endosymbiosys.
108
What is the theory of panspermia?
Suggest that simple forms of life are present in space and have seeded on earth after the cooling period which create life. it is supported by the idea that life started very early after the formation of earth, and that extremophiles are forms of life capable to survive difficult environment while in dormant state.
109
What does simple diffusion carry?
A type of passive transport where non polar molecules , steroid hormones, drugs and small polar molecules can diffuse easily without ATP. Makes it impossible for charged molecules to enter.
110
What does osmosis carry?
Only water molecules by simple diffusion of with the help of aquaporins.
111
What does facilitated diffusion carry?
When demand is too high for slow simple diffusion. Use transport pumps to move molecules quickly against their concentration gradient. It carries ions, sugars, amino acids, water molecules.
112
What is the primordial athmosphere?
Contained lots of water vapor, hydrogen sulfide, carbon dioxide, ammonia and methane. it was a reducing atmosphere meaning that these components could give electrons to create large organic molecules.
113
What is the atmosphere like today?
An oxidizing athmosphere containing 21% of O2 which prevents the organic molecules to be formed. The o2 was created by cyanobacteria that used the electrons in water for photosynthesis, once the water was oxidized, O2 was released and over time accumulated in the atmosphere.
114
What are microtubules?
They ae part of the animal and plant cytoskeleton. The movement of the cells is made by motor proteins that pull against microfillament while one end of the protein attached to the cell surface and the other end on the microtubule (worm like). ATP is needed for that walking process.
115
What is the sodium-potassium pump?
Large protein molecule with one end in the cytoplasm and one end outside. it moves positively charged ions out while bringing 2 K+ in the cell and pushing 3Na+ ions out against their concentration gradient. Creating an electrochemical gradient because levels and charges are different across the membrane. This gradient stores energy that is used later in other transport mechanisms.
116
What is glycolysis?
10 enzyme catalyzed reactions that oxidize glucose producing two molecules of pyruvate in cellular respiration. The free energy released from this oxidation will later synthezise ATP and NADH. Two phases : energy investment phase, one G3P is produced, payoff phase, each G3P produces 4 ATP an d2 NADH.
117
What is Rubisco?
Most abundant enzyme on earth,causes photorespiration. Because it catalizes RuBP with O2 instead of Co2, it forms a toxic product and the only way to eliminate it is through photorespiration.
118
What is bioluminescence?
Many organisms are, ATP excites an electron and when it returns to ground state, the energy is released as a photon of light. It is very efficient an do not loose much heat.
119
What is fluorescence?
Once a photon of light is absorbed, one of the fate for the excited electron is that it goes back to its ground state releasing its energy as heat or fluorescence. Fluorescence is the emission of light of a longer wavelength (lower energy), than the absorbed light.
120
What are microfillaments?
One of the 3 parts of the cytoskeleton of animal and plant cells. They are thin fibers of two rows of actin protein wound around each other in a double helix. Eukaryotic cell movement is done by motor proteins that pull against microfilaments or microtubules.
121
What is enthalpy?
Is the potential energy in a system.
122
What is free energy?
The portion of a system's energy that is available to do work.
123
What is an enzyme active site?
The place on it where catalysis occurs. It is a groove that is formed when a newly synthesized enzyme folds into its correct shape.
124
What is an allosteric site?
A site different than the active site on an enzyme where allosteric inhibitors or activators bind.
125
What is symport?
One of the two mechanisms of secondary active transport, symport and antiport. The solute moves through the membrane channel in the same direction as the ion providing it with energy. Also known in cotransport.
126
What is antiport?
One of the two mechanisms of secondary active transport, symport and antiport. The driving ion moves through the membrane channel in one direction, providing the energy for the active transport of a molecule in the opposite direction. Also known as exchange diffusion.
127
What is exocytosis?
When the cells carries bigger molecules from the cytoplasm to the cell exterior. Requires ATP. Using secretory vesicles that move through the cytoplasm to the plasma membrane where they fuse, releasing its content outside.
128
What is pinocytosis?
One of the pathways of endocytosis. Where extracellular water is taken with any other molecules that it contains by the plasma membrane bulging inwards and then pinching off as an endocytic vesicle.
129
What is the circadian rythm?
Physiological and behavioral responses to the internal clock that is set with the light environment.
130
What are ribozymes?
A group of RNA molecule that can catalyze reactions in a RNA molecule leading to their own synthesis. They are single stranded molecules that can fold into specific shapes, ribozyme's functions depends on how it is folded.
131
What is adiabatic cooling?
A decrease in temperature without the loss of heat energy. When warm air mass are expending when raising, the heat energy is distributed over a larger area. It then releases the moisture as rain.
132
What does ΔG mean?
The change in free energy.
133
What it means when a reaction has a positive ΔG
It will not be a spontaneous reaction because the change of free energy needs to be negative for it to happen spontaneously. The products have more free energy than the reactants = endergonic reaction.
134
What are gated channels?
One of the two things used in facilitated diffusion (gated, channel proteins) They transport ions and switch between open, closed or intermediate state depending on the changes in voltages across the membrane.
135
What is exchange diffusion?
One of the methods used in secondary active transport. ALso known as antiport, the driving ion moves through the channel in one direction, providing the energy for the active transport of another molecule in the other direction. It is done in red blood cells for the movement of chloride and bicarbonite ions through the channel.
136
What is a monsoon cycle?
A wind pattern that brings seasonally heavy rain to a region by blowing moisture-laden air from the sea to the land.
