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.
Which of the following factors does not affect soil formation?
a. precipitation
b. time
C. erosion
d. none of the above
Please select the best answer from the choices provided
B
Ο Ο Ο Ο
PLS HELP ASAP
Answer:
b is the answer
Explanation:
edge2021
A farmer decides to try to increase his profits by mating his two goats that produce the most milk together. The farmer’s descendants continue the process and over 400 years the family produces goats that make more milk than any in the country. Eventually the goats change enough that they are designated a new species. This is an example of:
A. Artificial selection
B. Acquired characteristics
C. Disruptive selection
D. Natural selection
Answer:
A.is the correct answer
Explanation:
People have been doing asimple form genetic enineeringfor thousands of years. This is called selective breeding. Selective breeding, or artifical selection, is a process where people try and improve plants and animals by selecting and breeding those that have desireable charactistics.
For example, a farmer might choose from his two largest cattle in his herd and breed them together so that the offspring will be even bigger and produce more meat.
During DNA replication, when the mRNA molecule is made by complementary base pairing, the percentage of adenine bases would be equal to which of the following bases in a RNA molecule?
Adenine
Cytosine
Guanine
Uracil
Answer:
I think the answer is uracil because it has the same percentage as thymine in RNA which is 30% and thymine has the same percentage as adenine.
I hope this helps
bones are moved by _____ muscles. these muscles are attached to bones by ________ and they work in ______ pairs. hen one muscles in pair _______ the other _______ and bones are _______ in a particular direction. muscles cell contain many ______ which release energy for movements.
fill in the blanks plz.
these are the word that want to come to those blanks
involuntary , relaxes , mitochondria , contracts , antagonistic , pushed , ligaments , pulled , ribosomes , muscles , tendons , voluntary.
Answer:
voluntary
tendons
antagonistic
contacts
relaxes
pushed
mitochondria
hope it helps
the words are in order starting from the top to the last one
what is the relationship between an enzyme and the substrates it can bind
Answer:
Enzymes and substrates bind to each other associating through various interactions, including hydrogen bonds, hydrophobic interactions, and covalent bonds.
Jim has become particularly interested in the genetic basis of cancer and has spent considerable time reading published papers about oncogenes. He learned that as early as 1972 researchers suggested that mutations in proto-oncogenes caused by carcinogens can convert them to oncogenes. He asked you to answer a couple of questions about this because he did not have the biology background to totally understand. Jim learned that some cancer cells produce more growth-stimulating proteins than others. What would you give him as a plausible explanation
Answer:
Proto-oncogenes may have mutated to become oncogenes in these cells
Explanation:
Cancer cells are characterized by key properties such as an abnormally rapid rate and poor differentiation. Proto-oncogenes are genes that lead normal cells to become cancer cells when they are mutated. Many proto-oncogenes are involved in the control and progression of the cell cycle, and apoptosis (programmed cell death) pathway. Some examples of protooncogenes include 1-the Ras gene, which is required for differentiation, growth, and cell survival (mutations of this gene have been reported in pancreatic cancer, lung cancer, colon cancer and thyroid cancer), 2-the Myc gene (mutated in Burkitt's lymphoma), 3- the Her2 receptor (a receptor kinase associated with breast cancer), etc.
HELPPPPPPPPPPPP!!!!!!!!!!!!!!!!!!!!!!!! All of the following cause mechanical weathering EXCEPT ____. a. ice c. burrowing animals b. tree roots d. carbonic acid
Explanation:
c. burrowing animals is the answer
Suppose you are a genetics counselor who is working with a 21-year-old pregnant woman who has just discovered that her father has Huntington's disease, a rare dominant autosomal trait. This disease usually develops in middle age, so people carrying this trait do not find out they have this genetic disorder until midlife. What are the chances that the child she is carrying will develop the disease
Answer:
s
Explanation:
Which of the following is not one of the steps of the water cycle?
A. Condensation of water vapor into clouds.
B. Throughflow of underground water back to the ocean.
C. Respiration of water into the atmosphere.
D. Transpiration of water into the atmosphere.
The option that is not one of the steps of the water cycle includes options C(Respiration of water into the atmosphere)
and D(Transpiration of water into the atmosphere).
Water cycle can be defined as the constant flow or movement of water through earth, atmosphere and the oceans either in liquid states or vapour.
The four main steps of water cycle includes:
EvaporationCondensationprecipitation and Collection (this leads to formation of underground water which gradually flows back into the oceans).In nature, water circulates mainly within the abiotic (non-living) environment; only a small proportion recycled through living organisms.
Therefore respiration and transpiration which occurs through living organisms doesn't form the major steps of water cycle, hence the correct option is C (Respiration of water into the atmosphere) and D (Transpiration of water into the atmosphere).
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Some of the cell membrane functions are similar to the ________ of the body.
the skin has cells like that
Which part of the brain is indicated by the arrow below?
Pons
Cerebellum
Cerebrum
Medulla oblongata
Answer:
the correct answer is option ( A ) pons
Explanation:
hope it helps you
Mark my answer as brainlist
have a nice day
Answer:
A. Pons
Explanation:
I got it right on my quiz :)
what is not a function of plasma membrane
Answer:
the control center of the cell.
Laying the groundwork for the 'germ theory' of disease _________ discovered that organisms cannot spontaneously arise, but must be introduced into an environment.
A. Anthony Van Leeuwenhoek
B. Louis Pasteur
C. Robert Hooke
D. Ernst Ruska
Laying the groundwork for the 'germ theory of disease, Louis Pasteur discovered that organisms cannot spontaneously arise, but must be introduced into an environment.
Who was Louis Pasteur?Louis Pasteur was a chemist and microbiologist. He is known for the discovery of vaccines, fermentation, and pasteurization.
The germ theory is given by Pasteur. He first of all states that process fermentation is done by living organisms, bacteria, and yeast.
Thus, option B. Louis Pasteur is correct.
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the scientific name of the great egret has recently been changed from Casmerodius albus to Ardea alba. What is a possible reason for the reclassification of egrets?
A) Allopatric speciation
B) Discovery of a different ancestor
C) A change in the mating behaviors
D) A change in their habitat and geological range
Answer:
B) Discovery of different ancestry
Explanation:
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a) What is the earth's path around the sun called? b) How long does it take for Earth to complete a complete circuit around the Sun? c) Name one planet that is closer to the Sun than Earth and another one that is further away. .
Tania looks at several different multivitamins in the store and notes that there are many different formulations with
varying amounts of several types of vitamins. She would like to choose a brand that only has the essential vitamins
that humans need to consume.
What are the vitamins that Tania should verify are in the product that she purchases?
O vitamins A, B, C, D, E, and K
O vitamins A, B, C, E, and K
O vitamins A, B, C, D, and E
O vitamins A, B, C, D, E, F, and K
What is the best description of connective tissue? Question 3 options: All of its cells rest on a basal lamina. All of its cells associate via cadherins in their plasma membrane. All of its cells are electrically connected via gap junctions. All of its cells are sparsely distributed in the extracellular matrix.
Answer:
Connective tissue is a group of tissues in the body that keep the body and its organs in shape while also providing cohesion and internal support.
All of its cells exist sparsely distributed in the extracellular matrix is the best description of connective tissue.
What is connective tissue?
Tissue that sustains, protects and provides structure to other tissues and organs in the body. Connective tissue also stores fat, permits the movement of nutrients and other substances between tissues and organs, and allows the repair of damaged tissue. Connective tissue exists created up of cells, fibers, and a gel-like substance.
Connective tissue is discovered in between other tissues everywhere in the body, including the nervous system. The three outer membranes (the meninges) that surround the brain and spinal cord exist composed of dense inert connective tissue.
Connective tissues bind systems together, form a framework and support for organs and the body as a whole, store fat, transport substances, defend against disease, and assist restoration of tissue damage.
Hence, All of its cells exist sparsely distributed in the extracellular matrix is the best description of connective tissue.
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Though plants, fungi, and prokaryotes all have cell walls, we place them in different taxa. Which of these observations comes closest to explaining the basis for placing these organisms in different taxa, well before relevant data from molecular systematics became available?
Answer:
Due to other differences.
Explanation:
The plants, fungi, and prokaryotes all have cell walls, we place them in different taxa because of the other differences such as mobility, mode of nutrition etc. Plants and fungi are not mobile means can not move from one place to another whereas prokaryotes are mobile. Fungi and prokaryotes are heterotrophs means that feed on other organism whereas plants are autotrophs means make their own food. There is also difference in their cell wall i.e. the cell of plants is composed of cellulose, the cell wall of prokaryotes especially bacteria is composed of peptidoglycans and the cell wall of fungi is composed of chitin.
All cells are contained within a membrane called the:
A. Cell wall
B. Cytoplasm bilayer
C. Cytosol
D. Phospholipid bilayer
Answer:
Phospholipid bilayer
Explanation:
That is essentially the primary componenent of the cell membrane where phospholipids form two layers.
Indica el período, el grupo y el número atómico de los elementos que se representan con las siguientes configuraciones electrónicas: 1. 1s2 Grupo: ______ Periodo: _______ 2. 1s22s22p63s1 Grupo: ______ Periodo: _______ 3. 1s22s22p63s23p64s2 Grupo: ______ Periodo: _______ 4. 1s22s22p63s23p64s23d1 Grupo: ______ Periodo: _______ 5. 1s22s22p63s23p64s23d104p3 Grupo: ______ Periodo: _______
Answer:
1. 1s² Grupo: 18 Periodo: 1
2. 1s²2s²2p⁶3s¹ Grupo: 1 Periodo: 3
3. 1s²2s²2p⁶3s²3p⁶4s² Grupo: 2 Periodo: 4
4. 1s²2s²2p⁶3s²3p⁶4s²3d¹ (electrones de valencia) Grupo: 3 Periodo: 4
5. 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p³ (electrones de valencia) Grupo: 15 Periodo: 4
Explanation:
La configuración electrónica de los elementos es la disposición de todos los electrones de un elemento en niveles y subniveles de energía (orbitales).
Hay 7 niveles de energía, numerados del 1 al 7, y en los que los electrones se distribuyen, lógicamente, en orden según su nivel de energía. Los electrones con menos energía girarán en el nivel 1. Cada nivel se divide en subniveles. Estos subniveles en los que se divide cada nivel pueden ser hasta 4. Estos 4 subniveles se denominan: s, p, d, f. En el subnivel s solo puede haber un máximo de 2 electrones, en p puede haber un máximo de 6 electrones, en el subnivel d 10 electrones y finalmente en el subnivel f puede haber un máximo de 14 electrones.
Por otro lado, los electrones de valencia son los electrones que se encuentran en la última capa electrónica (denominada orbitales de valencia) y tienen muchas posibilidades de participar en una reacción química.
En la tabla periódica, en cada período aparecen los elementos cuyo último nivel de su configuración electrónica coincide con el número del período, mientras que en cada grupo aparecen los elementos que presentan el mismo número de electrones en el último nivel ocupado o capa de valencia. Entonces:
1. 1s² Grupo: 18 Periodo: 1
2. 1s²2s²2p⁶3s¹ Grupo: 1 Periodo: 3
3. 1s²2s²2p⁶3s²3p⁶4s² Grupo: 2 Periodo: 4
4. 1s²2s²2p⁶3s²3p⁶4s²3d¹ (electrones de valencia) Grupo: 3 Periodo: 4
5. 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p³ (electrones de valencia) Grupo: 15 Periodo: 4
The purpose of Mendel's experiments with dihybrid crosses was to determine
whether:
A. an F2 generation could be produced from the Fi offspring.
B. one of two traits could be transformed by DNA.
O c. one trait would affect how another is inherited.
D. traits are controlled by more than one gene.
Answer:
C. one trait would affect how another is inherited
Explanation:
carbohydrate are store in animal cell in the form of
Answer:
molecule glycogen
Plants store carbohydrates in long polysaccharides chains called starch, while animals store carbohydrates as the molecule glycogen.
Name TWO disorders that may occur within this body system and discuss cause/diagnosis/treatment
Help plz
Answer:
Cancer and Arthritis
Explanation:
Some causes of cancer include smoking, obesity, and lack of nutrition. Cancer is diagnosed using a biopsy. A biopsy is a procedure in which the doctor removes a sample of tissue. A pathologist looks at the tissue under a microscope and runs other tests to see if the tissue is cancer. Some treatments for cancer include Chemotherapy, surgery, Radiation therapy, and bone marrow transplant.
The most common cause of arthritis is usually if your family has a history of arhritis. It is usually diagnosed with an x-ray or a blood test. Treatment includes Painkillers, physical therapy, and exercise.
Name the 5 systems of the human body.
Answer:
Skeletal System
Muscular System
Circulatory System
Endocrine System
Digestive System
are systems of the Human Body
Explanation:
Answer:
Digestive system
Circulatory system
Respiratory system
Nervous system
Skeletal system
which type of motion dose not change the amino produced
Answer:
silent mutation. have a great day! :)
what is photosynthesis?
Answer:
Photosynthesis is the process by which plants prepare food using water, sunlight, chlorophyll and carbon dioxide
Answer:
It is the process in which green plants use sunlight to make there own food .
Explanation:
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Dựa vào đặc điểm của vỏ quả và hạt, loại quả nào dưới đây được xếp cùng nhóm với quả mơ ?
A. Nho B. Cà chua
C. Chanh D. Xoài
Answer:
A and C
Explanation:
Scientific laws attempt to explain nature
True
False
Answer:
I think that is is false.
5. How could looking at the canopy help determine the difference between a forest and a
woodland?
Answer:
Forests naturally have a closed canopy permitting very little light to penetrate to the ground below. While woodlands have a more open canopy for light to go through it.
Explanation:
what are living organisms?
Answer:
In,biology, an organism is any organic, living system that functions as an individual entity. All organisms are composed of cells. Organisms are classified by taxonomy into groups such as multicellular animals, plants, and fungi; or unicellular microorganisms such as protists, bacteria, and archaea
Explanation:
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