Answer: At low temperatures the fluidity of the membrane decreases and it favors fluidity. The higher the concentration of unsaturated fatty acids, the less tightly the phospholipids can bind and the more fluid (more permeable).
Explanation:
The plasma membrane is a lipid layer that delimits the entire cell, dividing the extracellular medium from the intracellular (the cytoplasm of a cell). They are composed of phospholipids, which are molecules composed of glycerol, a phosphate group and two lipid chains (such as fatty acids). Glycerol is a three-carbon molecule that functions as the backbone of this membrane. A geometry is formed that allows the phospholipids to line up side by side to form broad sheets. They are insoluble in water, but their unique geometry causes them to aggregate in layers without any energy input, as they possess a hydrophilic phosphate head and a hydrophobic tail consisting of the two fatty acid chains. The hydrophilic heads of the phospholipids in a bilayer membrane face outward and are in contact with the aqueous fluid inside and outside the cell. Because water is a polar molecule, it readily forms electrostatic (charge-based) interactions with the phospholipid heads.
Selective permeability is a property of the plasma membrane and other semipermeable membranes that allow only certain particles to pass through them. In this way, those particles that are needed by the cell can enter the cell and those that are not useful to the cell are prevented from entering. In the same way, the cell can eliminate the particles it has produced as waste. In this way, the entry and exit of substances through the membrane is regulated and the correct functioning of the cell is achieved.
For a particle to be able to cross the plasma membrane it must have a size equal to or smaller than the pores of the membrane, it must have the opposite charge to the charge of the membrane or simply have a neutral charge, and if it is larger than the pores it must be dissolved in a solution, decreasing its size and thus be able to enter the cell through the membrane.
Plasma membranes are fluid and this fluidity depends on their lipid composition and temperature. Depending on the temperature, membrane lipids can be found in two different states or phases: gel (solid-like, with more rigid hydrocarbon chains) and liquid crystal (more fluid, with more mobile hydrocarbon chains). At low temperatures the fluidity of the membrane decreases and in these conditions the increase of its concentration favors fluidity. The temperature at which the transition from one state to the other occurs is the phase transition temperature (Tc). At values below Tc, the bilayer is in the gel state and at higher values it passes to the liquid crystal. It should be noted that there is an equilibrium between the gel state and the liquid crystal state and that the characteristics of the lipids of the bilayer condition the transition temperature. In the case of bilayers consisting of only one type of lipid, the Tc is well defined. But biological membranes are complex lipid mixtures and the transition from one state to another occurs over a range of temperatures. The presence of short-chain or unsaturated fatty acids reduces the transition temperature, while saturated fatty acids and the increase in the length of the hydrocarbon chains cause this temperature to rise. Then, phospholipids with unsaturated fatty acid tails cannot bind as tightly due to the bent structure of their tails. For this reason, a membrane of unsaturated phospholipids remains fluid at lower temperatures than a membrane of saturated phospholipids.
The fluidity of a membrane is the ability of a molecule to move through it. In short, the higher the concentration of unsaturated fatty acids, the less tightly the phospholipids can bind and the more fluid (more permeable) the membrane will be even at low temperatures. However, at low temperatures the fluidity of the membrane decreases (lower permeability) but the effect will depend on the composition of the fatty acids. To determine the exact permeability, it is necessary to relate the concentration of unsaturated bonds and the length of the fatty acids in the phospholipids and the temperature.
A specimane collection helps a scientsist do research by:
A. Asembling a large number of sample comparisons
B.providing a way to afford even the most expensive equpment
C.creating a realistic depiction of an imaginary undersea world
D.summerizing the results of an other scientists investigations
Answer A:
Explanation:
Which is a molecule found in the body?
O urethra
O nutrients
O atoms
O water
Answer:
water
Explanation:
Answer:
Water
Explanation:
Based on his experiments, Mendel concluded that each trait was controlled by two _____.
Based on this map, which of the following countries do you think contributes most to global climate change?
Answer:
The answer is C.united states
¿Qué acciones podrían realizar para poder reducir los gases de efecto invernadero como el Co2?
AYUDA POR FAVOR
DOY CORONITA Y 5 ESTRELLAS
Explanation:
Ser conscientes del impacto de las emisiones de CO2. ...
Reducir el uso del coche privado. ...
Practicar una movilidad sostenible. ...
Aumentar nuestra eficiencia energética. ...
Consumir energía renovable. ...
Seguir una dieta con baja huella de carbono. ...
Convertirse en un consumidor sostenible.
Más elementos…
pls help I will mark brainlest
Answer:
Renewable resources can be replaced by natural processes as quickly as humans use them. Examples include sunlight and wind. Nonrenewable resources exist in fixed amounts. They can be used up.
I Hope this will help you if not so advance sorry :)
Why is avian influenza (H5 N1) rarely transmitted from poultry to humans? Why is it is often lethal
in humans? Why is it rarely spread from person to person?
Answer:
Lacks the right key to unlock many cells.
Explanation:
Avian influenza (H5 N1) rarely transmitted from poultry to humans because it lacks the right key to unlock many cells in the upper respiratory tract so due to this action the virus is rarely transmitted to humans. Sometimes it is lethal to humans due to absence of antibodies for this type of virus. It is rarely spread from person to person due to inability to enters the other human body.
What adaptations did Charles Darwin notice in the finches of the Galapagos Islands that helped him develop his theory of evolution by natural selection?
A. All of the finches looked the same regardless of the island from which they came.
B. The finches had the same beak sizes and shapes as the mainland finches.
C. The finches had gone extinct from the islands due to volcanic activity.
D. The finches had beaks of different sizes and shapes that were suited to the available food.
Answer:
the answer is D
Explanation:
hope this helps:)
Charles Darwin noticed that the finches had beaks of different sizes and shapes that were suited to the available food. Option D is correct.
Changes in their beak size and shape have allowed them to adapt to different food sources: seed, insect, cactus flower and fruit, or even bird’s blood. Adaptive radiation is a well-known feature of the Galapagos finches.
Darwin concluded that these differences allowed the finches to better adapt to the food in their specific habitat - thin sharp beaks where the birds feed on insects and grubs and large claw-like beaks where they feed on buds, fruits, and nuts.
So the correct option is D.
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As compared to the circulatory system of most fishes, the circulatory system of adult amphibians has the advantage of a single circuit. partially-separate circuits for gas exchange and systemic delivery of blood. complete separation between oxygenated and deoxygenated blood. a four-chambered heart. a pocket of the gut that serves as an air bladder.
Answer:
Partially separate circuits for gas exchange and systemic delivery of blood.
Explanation:
Adult amphibians have separate circuits for gas exchange and systemic delivery of blood. Fishes usually breathe through gills and very few have nostrils. The fishes can breathe underwater with the help of their gills.
What is phagocytosis?
A) how Trichoplax adhaerens processes stimuli
B) how Trichoplax adhaerens reproduces sexually
C)how Trichoplax adhaerens moves using its cilia
B)how Trichoplax adhaerens eats by engulfing its food
CAN I GET ANSWERS ASAP PLS
Answer:
D - How trichoplax adhaerens eats by engulfing it's food
Phagocytosis is a process in which Trichoplax adhaerens eats by engulfing its food, which is in Option D. It is a process by which the cells engulf the food that is coming from the outside of the cell.
What is phagocytosis?The cell has many organelles, such as the lysosome, vacuole, cell nucleus, etc., but each organelle has a special function, and one organelle cannot take over the function of another organelle. The lysosomes have a very unique and acidic environment that destroys the organelles, such as old organelles, and kills viruses, etc.
When outside food particles or pathogens enter the cell, they enter as a vacuole, and the cell transports them from the outside to the inside through a variety of processes. The cell then eats them, a process known as phagocytosis, and if it is a virus, the lysosome degrades it.
Hence, Phagocytosis is a process in which Trichoplax adhaerens eats by engulfing its food, which is in Option D.
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An important species of an Atlantic ocean community is the giant kelp, which helps form a suitable habitat for
fish and marine invertebrates.
Which of the following best describes the role of giant kelp in its ecosystem?
Choose 1 answer:
A dominant species
A pioneer species
A foundation species
An invasive species
Answer:
The giant kelp is a foundation species in its ecosystem.
Explanation:
The kelp acts as a home to the fish and the marine invertebrates, so they can be best described as a foundation species, or species that make an ecosystem suitable for a group of other species.
Answer:
from khan academy :)
Which plant is use for pine I am just in grade 5
Answer:
Pine may also refer to the lumber derived from pine trees
pine is one of the more extensively used types of wood used as lumber.
Explanation:
do fertilised eggs divide to form a foetus
The sympathetic and parasympathetic nervous systems are both part of which division of the nervous system?
the central nervous system
the peripheral nervous system
the somatic nervous system
the autonomic nervous system
Answer:
The answer is D. The autonomic nervous system.
Answer:
(D): the autonomic nervous system
Explanation:
Got it right on edge! Good Luck <3
Prior to the industrial revolution in the mid-1800s, a species of moth had light-colored wings speckled with small black spots. This coloration camouflaged the moths resting on the birch trees growing in their native habitat, since birch bark has similar coloring. In the early 1900s, this changed as dark soot produced by industrial pollution coated birch trees such that the trees lost their speckled coloring. Years later, it was observed that the moths of this species had changed from being light and speckled to being solid black. Which is the most plausible reason for this change
Answer:
The dark colored moths were due to a genetic mutation, and were more than likely present before the Industrial Revolution. Their fitness was low because predators could easily see them on the light-colored trees. They would be eaten before they could reproduce and pass on their genetic mutation. After the trees became darkened by soot, the darker colored moths now had the survival advantage, able to "hide" from predators. The lighter colored moths became more visible to predators, and the advantage shifted. Now, the light colored moths were more visible to predators, were eaten, and didn't have the chance to reproduce. The darker moths with the mutation had the survival advantage, blending in with the soot-covered trees, and were able to reproduce at higher rates, passing the mutation on to later generations.
Imagine you do a test cross between a purple-flowered pea plant having serrated leaves (a dominant trait) and a white-flowered pea plant having smooth edges. If the purple-flowered plant is heterozygous for both traits, the expected ratio in the offspring is 1 purple-serrated:1 purple-smooth:1 white-serrated:1 white-smooth. Instead, you see 4 purple-serrated:1 purple-smooth:1 white-serrated:4 white-smooth. What is the explanation of this ratio
Answer:
genes for flower color and edge shape are linked. They do not assort independently.
Explanation:
Available data:
test cross between a purple-flowered pea plant having serrated leaves and a white-flowered pea plant having smooth edges.serrated leaves → dominant trait smooth edges → recessive traitpurple color → dominant traitwhite color → recessive traitF1: 4 purple-serrated:1 purple-smooth:1 white-serrated:4 white-smooth.There are two genes involved in the cross. The expected ratios are 1:1:1:1 because we assume genes assort independently. However, we see a different phenotypic distribution. When phenotypic ratios differ from the expected ones, it means that genes are linked.
To know if two genes are linked in the same chromosome, we must observe the progeny distribution. If individuals, whose genes assort independently, are test crossed, they produce a progeny with equal phenotypic frequencies 1:1:1:1. But if instead of this distribution, we observe a different one, that is that phenotypes appear in different proportions, we can assume that genes are linked in the double heterozygote parent
A specific defense is a(n)
Answer:
The adaptive immune system.
Explanation:
Recognizes and attacks specific pathogens
Hope this helps!
--Applepi101
Question 1 of 25
The overall increase in the amount of carbon dioxide in the atmosphere
directly corresponds with all of the following except.
A. the decrease in the growth rate of some human populations.
B. changing weather patterns.
C. the overall increase in average global temperatures.
O D. the melting of the ice caps.
answer h and i urgently
no explanation needed
Answer:
h. I think option c growth of an organism in not true
The Kirkwood gap is a gap with no asteroids as a result of the gravitational pull of____.
The Kirkwood gap is an asteroid belt region situated between the orbits of Mars and Jupiter that has a significant depletion of asteroids. This chasm is caused by Jupiter's gravitational pull, which causes asteroids to move around and destabilase their orbits.
What is Kirkwood gap?The Kirkwood gap is an asteroid belt region located between the planetary orbits of Mars and Jupiter that has a significant depletion of asteroids. This chasm is caused by Jupiter's gravitational pull, which causes asteroids to migrate and destabilize their orbits.
Jupiter's gravity has a major influence on the asteroid belt, causing their orbits to grow unstable and potentially crash with other objects. As a result, asteroids in some asteroid belt regions may be expelled from their orbits or smash with other things, leaving gaps or areas with fewer asteroids.
The Kirkwood gap was named after the American scientist Daniel Kirkwood, who first observed the decrease of asteroids in this region in the year 2000.
Therefore, the Kirkwood gap is an asteroid belt region situated between the orbits of Mars and Jupiter that has a significant depletion of asteroids.
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En el hombre el color negro de los ojos “A” domina sobre el color azul “a” Una pareja en la que el hombre tiene los ojos negros y la mujer ojos azules tienen dos hijos, uno de ellos de ojos negros y el otro de ojos azules. Averiguar:
a) El genotipo del padre.
b) Realizar el cruzamiento.
c) Porcentaje genotípico de los hijos.
El enunciado hace referencia a un caso de herencia monogénica y dominancia completa para el rasgo 'color de ojos', donde el padre es heterocigota y la madre es homo-cigota recesivo.
Las respuestas a estas preguntas son:
a) Genotipo del padre: Aa (ojos negros)
b) Cruzamiento: Aa (padre) x aa (madre)
c) Frecuencias genotípicas esperadas: 1/2 Aa; 1/2 aa
En genética, dominancia completa se refiere al proceso de herencia en la cual un individuo heterocigota, es decir, el individuo que presenta dos alelos diferentes para el mismo gen, presenta el mismo fenotipo que un individuo homo-cigota para el alelo dominante (el alelo dominante es aquel que enmascara la expresión del alelo recesivo en individuos heterocigotas).
En este caso, el carácter 'color de ojos' presenta un patrón de herencia monogénica, donde el alelo 'A' dominante codifica para el rasgo fenotípico ojos negros, mientras que el alelo 'a' recesivo codifica para el rasgo fenotípico ojos azules.
En el ejemplo, la pareja tuvo progenie en la cual uno de los hijos presenta el rasgo recesivo ojos claros, y por lo tanto el padre debe ser heterocigota y poseer un alelo recesivo 'a'; mientras que la madre expresa el fenotipo recesivo y por lo tanto su genotipo es 'aa'. En consecuencia, el cruzamiento de un padre heterozigota 'Aa' con una madre homo-cigota recesivo 'aa' producirá una descendencia con una frecuencia genotípica esperada de 1/2 (50%) de hijos con ojos 'color negro' de genotipo Aa y 1/2 (50%) de hijos con ojos 'color celelste' de genotipo aa >>
Cruzamiento: Aa (padre) x aa (madre)
Gametos padre: 1/2 A; 1/2 a
Gametos madre: 100% a
Cuadro de Punett (combinaciones gaméticas):
A a
a Aa aa
a Aa aa
En consecuencia, este cruzamiento producirá 50% individuos ojos color negro (genotipo Aa) y 50% individuos con ojos color celelste (genotipo aa)
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Which circumstance can cause positive
population growth?
A.
The immigration rate is lower than the death rate.
© B. The death rate is higher than the birthrate.
O C. The birthrate is higher than the death rate.
• D. The emigration rate is the same as the birthrate.
Answer is birthrate D
Answer:
C
Explanation:
When the birthrate is higher than thedeathrate
What happens with the release of DDT into the food chain zooplankton -- small animal -- large animal-- bald eagle? And what process is involved
Answer: The process involved is called BIOACCUMULATION.
Explanation:
Dichlorodiphenyltrichloroethane (DDT) is a type of pesticide used in agricultural control of pests. It's use has been restricted because of its involvement in bioaccumulation. The pesticide is known for accumulating in food webs and persisting in soil and river sediments. This leads to it's accumulation (build up) in living organisms.
Pesticides and fertilizers are used in crop cultivation. Rain and irrigation water wash these chemicals, especially the soluble nitrate fertilizers, into the ground water and they eventually get into rivers, lakes and seas.
These pesticides such as DDT are synthetic organic compounds that are non-biodegradable. When they are washed into the ground water, they accumulate in the bodies of plants (zooplankton). These are eaten by small fishes which are in turn consumed by larger fishes. These large fishes are hunted as prey by the bald eagle.
DDT builds up in these bald eagle causing them to lay eggs with thin shells. As a result, the eggs break easily causing a fall in the eagle population.
Fire suppression has been an official management policy in a variety of Northern Ghana ecosystems. Discuss examples of how this has impacted community composition. Describe how these examples are either consistent or inconsistent with the predictions of the Intermediate Disturbance Hypothesis. Be sure to take into account various aspects of the disturbance regime (e.G. Frequency and intensity).
The answer to these questions are the following:
1. It has been suggested that fire suppression management might increase the area affected by increasing the frequency of high-severity fires in the Idaho-Montana Rockies (USA) and in the chaparral vegetation of California
2. Fire suppression>> alteration of composition, distribution, and density of species
3. Data are consistent with the intermediate disturbance hypothesis
Fire suppression management is a strategy focused on trying to stop wildfires. The fire suppression management strategy has recently been criticized for accumulating dead biomass in fire-prone ecosystems, thereby leading to high intensity and high severity fires when these areas do burn with wildfire. It has been shown that fire suppression may negatively alter the composition, distribution, and density of species (both animals and plants), especially in ecosystems having high-frequency and low-intensity fires.
In the Idaho-Montana Rockies (USA), it has been shown that high-severity fires increased their frequency in the period from 1975 to 2012 than in the period from 1935 to 1974, when the fire suppression management strategy coincided simultaneously with cooler and moister conditions that were conducive to them.
The intermediate disturbance hypothesis states that species diversity is maximized at intermediate-scale disturbances. There are many ecologists that disagree with this hypothesis, indicating that the association between ecological disturbance and species diversity does not follow a unimodal distribution. In the example of the Idaho-Montana Rockies, data are consistent with the intermediate disturbance hypothesis because the intermediate disturbance hypothesis indicates that species diversity is highest in areas that have had an intermediate frequency and scale of disturbances (i.e., a fire suppression strategy might decrease the frequency of wildfires but it increases the risk of high severity fires).
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ASAP
What does the ‘fluid’ part of the Fluid Mosaic Model mean?
A. The proteins float around in the membrane as if in a fluid.
B. The lipids are suspended in a fluid.
C. The membrane creates necessary fluids for the cell.
D. It is fluid because it is adaptable to change.
Answer:
A) The proteins float
Explanation:
The proteins float around freely
describe how the structure of the cuticle, palisade mesophyll, spongy mesophyll and guard cells are adapted for their functions
Answer:
Cuticle - It also has a waxy material that protects the leaf from attacks by bacteria, protects inner tissues from mechanical damage and acts as a water proof layer to prevent excessive water loss.
Palisade mesophyll - They have many chloroplasts used to absorb light energy used for photosynthesis.
Spongy mesophyll - The cells are loosely packed together leaving air spaces that allow for air circulation and gaseous exchange.
Guard cell - They have thick inner walls and thin outer walls to control the opening and closing of the stomata.
Tại sao khi chi bị đau một bộ phận nào đó trong có thể những ta vấn thấy toàn có thể bị ảnh hưởng ?
Answer:
Sorry I can't understand anything
What group of archaebacteria is both thermophilic and acidophilic?
Pyrogens
Methanogens
Thermoacidophiles
Halophiles
Answer:
Thermoacidophiles
What does the phosphorylation of Cdc25 by M-Cdk do? Question 4 options: It inactivates Cdc25, which promotes activation of more M-Cdk. It activates Cdc25, allowing the cell to exit mitosis. It activates Cdc25, which inactivates M-Cdk. It inactivates Cdc25, preventing further activation of M-Cdk. It activates Cdc25, which in turn activates more M-Cdk.
Answer:
It activates Cdc25, which in turn activates more M-Cdk
Explanation:
Cyclin are enzymes that regulate cell cycle progression by the activation of cyclin-dependent kinases (CDKs). These cyclins have no enzymatic activity on their own but they can activate Cdks by binding and phosphorylating them. CDKs can be activated by phosphorylation of activating sites and/or dephosphorylation of inactivation sites. Moreover, M-phase cyclins are cyclins that form M-CDK complexes in order to modulate the cell's entry into mitosis. Cdc25 is a phosphatase involved in the eukaryotic cell cycle which is well-known to regulate the entry into and progression during S (DNA Synthesis) phase and mitosis. In this regard, it has been shown that mitotic phosphorylation of Cdc25 by M-Cdks increases its intrinsic phosphatase activity, thereby Cdc25 is able to remove inhibitory phosphates from M-Cdk and, consequently, activate more M-Cdks.
what do you mean by components of mixture?
Answer:
The components of a mixture are the items that are mixed together.
