The oxygen created during photosynthesis comes from water, not carbon dioxide.
By 1940, chemists began employing heavy isotopes to track photosynthetic processes. Early investigations employed water labeled with an oxygen isotope (18O). Plants that photosynthesized in the presence of H218O-containing water generated 18O-containing oxygen gas; plants that photosynthesized in normal water produced normal oxygen gas. These findings confirmed van Niel's notion that the oxygen gas created during photosynthesis is obtained from water.
Van Niel's proposal (that oxygen produced during photosynthesis originates in water rather than carbon dioxide) was significant because the popular (though invalid) theory was that oxygen was removed from carbon dioxide (rather than hydrogen from water, releasing oxygen) and carbon was then combined with water to form carbohydrate (rather than the hydrogen from water combining with CO2 to form CH2O).
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Having a complete set or sets of chromosomes is called ________. euploid diploid aneuploidy monoploid ploidy
Having a complete set or sets of chromosomes is called euploid
aneuploidy is a circumstance that exists when an organism gains or loses one or greater chromosomes but now not a whole haploid setThe failure of one or extra pairs of homologous chromosomes or sister chromatids to separate usually during nuclear division, commonly ensuing in an bizarre distribution of chromosomes within the daughter nuclei. is known as non disjunction. Nondisjunction at some point of either meiosis I or II within the female gameteMonosomy s the precise term that describes the loss of a single chromosome (2n - 1)Aneuploidy is the condition that exists when an organism gains or loses one or more chromosomes but now not a entire haploid setTo know more about euploid visit : https://brainly.com/question/22271293
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Protein channels that are situated between cells create small pores for the passage of small substances are known as?
According to the research, the correct option is gap junctions. Protein channels that are situated between cells create small pores for the passage of small substances are known as gap junctions.
What are gap junctions?They are molecular complexes made up of connexins as channels or connection structures between cells that allow the passage of small molecules and electric current.
In this sense, these channel structures formed by proteins allow the adaptive responses of differentiated cells and the synchronization of cell function, the transmission of the electrical impulse, among many other biological activities.
Therefore, we can conclude that according to the research, the correct option is gap junctions. Protein channels that are situated between cells create small pores for the passage of small substances are known as gap junctions.
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How does productivity increase in terrestrial ecosystems? in aquatic ecosystems?.
In terrestrial ecosystems, productivity increases by moisture availability, temperature, length of seasons, and annual temperature.
A terrestrial ecosystem is a non-aquatic environment and is an area where all terrestrial organisms either biotic or abiotic interact with each other.
There are five primary terrestrial ecosystems which are tropical rainforests, deserts, grasslands, tundra, and taigas.
These ecosystems have a diverse variety of species and rich biodiversity.
Moreover, the particular characteristics of this area are less water availability, temperature fluctuations, and higher availability of light and gases.
Examples of terrestrial plants are the Chinese privet, Autumn Olive and British Yellowhead.
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Adding what groups to histones tightens the DNA and prevents transcription.
Answer: Addition of methyl groups to histones by histone methyltransferases, can either activate or further repress transcription, depending on the amino acid being methylated and the presence of other methyl or acetyl groups in the vicinity. The fundamental unit of chromatin, called a nucleosome, contains DNA wound around a protein octamer.
Explanation:
After surgical removal of an infected gallbladder, a person must be especially careful to restrict dietary intake of a. starch. b. protein. c. sugar. d. fat.
d. fat The removal of the gall bladder will have an influence on the generation of bile, which will affect fat digestion because bile is essential for breaking down large fat molecules and commencing digestion.
What are the risks of having one's gallbladder removed?Leakage of bile
However, once the gallbladder is removed, bile fluid may occasionally flow into the belly (abdomen). Belly ache, feeling nauseous, a fever, and a distended tummy are all symptoms of a bile leak.
After gallbladder surgery, eating the incorrect foods can cause discomfort, bloating, and diarrhoea. To avoid stomach discomfort, avoid high-fat or spicy meals such as French fries and potato chips. Meats high in fat, such as bologna, sausage, and ground beef
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Which of these ecosystems has the lowest net primary production per square meter? a. a salt marsh b. an open ocean c. a coral reef d. a tropical rain forest
An open ocean has the lowest net primary production per square meter.
An ecosystem is a region where a bubble of life is created by plants, animals, and other organisms interacting with the weather, environment, and other factors. Abiotic variables, or nonliving components, coexist with biotic components in ecosystems. Plants, animals, and other species are biotic factors. Along with rocks, temperature and humidity are abiotic variables. Every component of an ecosystem is directly or indirectly dependent upon every other component. An ecosystem's temperature changes frequently have an impact on the types of plants that may flourish there, for example. Animals who rely on plants for food and refuge will need to relocate to a different ecosystem to adapt to the changes.
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A scientist is investigating a new drug that will cure the common cold. The scientist should give the __________ group an empty pill, rather than the pill with the drug being tested.
1. variable
2. control
3. test
4. experimental
If a drug mimicked the activity of GABA in the CNS, what general effect on behavior might you expect? Explain.
GABA is an inhibitory neurotransmitter, thus it makes sense that this medication will reduce brain activity. One could anticipate that a decline in brain activity would halt or diminish behavioral activity.
What is the impact of GABA in the CNS?(GABA) is an amino acid that serves as the central nervous system's main inhibitory neurotransmitter (CNS). By preventing nerve transmission, it works to lower neuronal excitability.
The main inhibitory neurotransmitter, GABA lowers the activity potential of the neuron.
The threshold potential is the point below which a neuron ceases to produce action potentials and, as a result, ceases to excite neighboring neurons.
Therefore, as a result of their drug usage, they could exhibit bad social behaviors, which affects both their professional performance and interpersonal connections.
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Which step of the cell cycles shown in the image is Vindlastine MOST likely to interrupt when given to patients with lung cancer, and why ?
Vinblastine binds to microtubular proteins in the mitotic spindle, thereby preventing cell division during metaphase.
Vinblastine is utilized in aggregate with different chemotherapy drugs to treat Hodgkin's lymphoma and non-Hodgkin's lymphoma styles of cancer that begin in a sort of white blood cellular that commonly fights contamination, and most cancers of the testicles.
Lung most cancers develops while everyday lung cells exchange, or mutate, in a way that alters their herbal boom and loss of life cycle, resulting in unregulated mobile department that produces too many cells. The hastily dividing cells do not perform the functions of ordinary lung cells or become wholesome lung tissue.
In many most cancers cells the variety of chromosomes is altered so that there are either too many or too few chromosomes inside the cells. these cells are said to be aneuploid. mistakes might also occur at some stage in the DNA replication resulting in mutations and in all likelihood the development of cancer.
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How much kinetic energy does a 50 kg object have it is
moving at a velocity of 1 m/s?
J
Do not Include units in your answer.
The power an object has as a result of motion is known as kinetic energy. A force must be applied to an object in order to accelerate it. We must put in effort in order to apply a force. After the work is finished, energy is transferred to the item, which then moves at a new, constant speed. Answer - [tex]25[/tex]
Kinetic energy has the following formula:
K.E. = [tex]\frac{1}{2} mv^{2}[/tex], where m is the object's mass and [tex]V[/tex] is its square velocity. The kinetic energy is measured in kilograms-meters squared per second squared if the mass is measured in kilogram and the velocity is measured in metre per second.
Solution :
Mass (m)= [tex]50 Kg[/tex]
Velocity (v) = [tex]1\frac{m}{s}[/tex]
Kinetic Energy = [tex]0.5 mv^{2} J[/tex]
= [tex]0.5*50*1^{2}[/tex]
= [tex]25[/tex]
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Why are mycoplasmas resistant to antibiotics that interfere with cell wall synthesis?
All the mycoplasmas that lack of the cell wall and, therefore, all are inherently resistant to the beta-lactam and antibiotics (e.g., penicillin).
The cell wall is surrounds by the plasma membrane of the plant cells and that provides the tensile strength and the protection against the mechanical and the osmotic stress. It can also be allows cells to develop the turgor pressure, which is the pressure of the cell that contents against the cell wall. Its main function was to give the cell rigidity, the strength, and the protection against the mechanical stress. for Examples of the organisms with the cell walls are plants, the fungi, protists (particularly molds and algae), and the most of the bacteria (few exceptions are the mycoplasma and the L-form bacteria) have the cell walls
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whenever one turns the pages of a book, uses a pen to take notes, or raises one's hand, one's actions are made possible by the nervous system.
whenever one turns the pages of a book, uses a pen to take notes, or raises one's hand, one's actions are made possible by the somatic nervous system.
The somatic nervous system, also known as the voluntary nervous system, is the area of the peripheral nervous system that controls skeletal (voluntary) muscles to control body movement. It also connects the organism to its environment by receiving external stimuli through the senses of sight, hearing, taste, and smell. In contrast to the autonomic nervous system, which functions largely independently of conscious control in innervating heart muscle and exocrine and endocrine glands, the somatic nervous system uses efferent motor nerves to govern voluntary actions like walking and smiling.
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The gross domestic product of India in 2009 was $1,236,000,000,000($1.236 trillion).how much in dollars was produced per person
$1070 dollars was produced per persons.
India's population measured in 2009 was 1.155 billion.
In order to determine the GDP in dollar produced per person, the total GDP of the country measured needs to be divided by the total population of the country .
Here, total GDP of India is $1.236 trillion.
Hence GDP per person in dollars is 1.236/1.155 =$1070.
What is meant by the GDP and how it is measured?
GDP measures the money value of final goods and services—that is produces in a financial year , those that are bought by the final user—produced in a country in a given period of time .It counts all of the output created within the boundaries of a country.
How GDP of India is calculated?India's GDP is measured with two different methods, one on economic activity , and the second on expenditure . The factor cost method examines the performance of eight different industries.
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Which drugs blocked naloxone binding in this experiment? What do these results indicate about the brain receptors for naloxone?
Morphine, methadone, and levorphanol can block naloxone binding. Naloxone is an opioid drug used for reversing various effects like excessive sleeping, slow breathing, etc.
What is naloxone?The effects of opioid drugs, such as excessive sleepiness, slowing breathing, or loss of consciousness, are blocked or reversed by naloxone. A narcotic is another name for an opioid.
In an emergency, naloxone is used to treat a kid or adult who may have overdosed on opioids. In the event of an overdose, naloxone should not be administered in place of immediate medical attention.
An opioid overdose could be treated with naloxone. Symptoms of an opioid overdose might include extreme sleepiness, pin-point pupils, delayed breathing, or no breathing at all.
Therefore, morphine, methadone, and levorphanol can block naloxone binding.
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Explain how nitrogen and phosphorus, the nutrients that most often limit primary production, are necessary for the Calvin cycle to function in photosynthesis (see Concept 10.3).
The importance of nitrogen and phosphorus to the Calvin cycle reducing equivalent NADPH and the energy molecule ATP.
What is the role of nitrogen and phosphorus in the Calvin cycle?The Calvin cycle is a cycle which consists of light-independent chemical reactions that convert carbon dioxide and hydrogen carried by hydrogen transfer compounds into glucose.
The steps of the Calvin cycle are:
carbon fixation,reduction, andregenerationThe role of nitrogen and phosphorus is that they are part of the reducing equivalents NADPH which donates hydrogen for the reduction of carbon dioxide in the Calvin cycle and ATP which provides energy that drives the reactions.
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you are estimating the time since the divergence of two species and used hemoglobin for your molecular clock. you would like to get independent support for your estimate. if you also use cytochrome c, which result do you expect?
The number of amino acid differences between the two species will be fewer for cytochrome c than for hemoglobin.
What can be utilized as a molecular clock to estimate the time since organisms diverged from a familiar?
A molecular watch uses DNA sequences (or the amino acid sequence of proteins that DNA encodes) to calculate how long it has been since related species separated from a common ancestor
Why does hereditary drift have more of an impact on the evolution of small peoples than large ones?
Small populations tend to lose hereditary diversity more quickly than large populations due to stochastic sample error (i.e., genetic drift). This is because some interpretations of a gene can be lost due to accidental chance, and this is more likely to occur when residents are small.
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Complete Question is,
a) The number of amino acid differences between the two species will be the same for both genes.
b) The number of amino acid differences between the two species will be fewer for hemoglobin than for cytochrome c.
c) The number of amino acid differences between the two species will be fewer for cytochrome c than for hemoglobin.
It is hypothesized that RNA may have evolved before DNA because RNA molecules
were the first molecules synthesized by Miller and Urey
are more important to genetic inheritance than DNA
can catalyze a variety of biologically important reactions
are found in more modern cells than are DNA molecules
It is hypothesized that RNA may have evolved before DNA because RNA can catalyze a variety of biologically important chemical reactions (Option 3 is correct).
What is RNA?RNA is a special class of nucleic acid that serves as the reservoir of genetic material for certain viruses, which is composed of only one nucleotide chain strand listed of two stands as occur with the double helix of DNA.
In conclusion, it is hypothesized that RNA may have evolved before DNA because RNA can catalyze a variety of biologically important chemical reactions (Option 3 is correct).
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Answer: C. can catalyze a variety of biologically important reactions
Proof of validity is shown below.
What does a human being , plants, mushrooms and fish have about them that makes them different
Answer:
biological differences such as, different appearances, and different functions. mushrooms are a fungi and they break down/decompose dead plants and such. fish eat algae and other fish. and humans eat plants, and animals. we all do different things. think about it can a mushroom walk, can a fish walk? humans breath air, mushrooms make air, and fish breath oxygenated H2O
Which one of these are possible results?
Group of answer choices
Seeing the flowers on a plant
Counting the leaves on a plant
The actual number of new leaves on a plant
How much sunlight you put the plant in
How often you watered the plant
Seeing the pretty leaves on a plant
Please answer QUICKLY!!
A possible result would be the actual number of new leaves on a plant.
What are results?
Results are the outcome of investigations.
Results are unique from observation. Observations are the information we sense from a phenomenon. Results, on the other hand, are the information that we observed and recorded.
Going by these definitions:
Seeing the flowers on a plant will be an observation.
How much sunlight you put the plant in is a variable.
How often you water the plant is also a variable.
Seeing the pretty leaves on a plant is an observation.
The only option that is a result is the actual number of new leaves on a plant.
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I dont understand how to do this. Geometry
The X of the angle <CDB represented as 7X is = 5.86.
Calculation of the angleFrom the diagram, line BD divides triangle ∆ ADB into two identical triangles.
Triangle ∆ ABD = triangle ∆ CBD
Notice that < ADC = an acute angle which is = 90°; and
<ADC = < ADB + < CDB
But , < ADB= 49° and < CDB = 7x
90° = 49 + 7x
Make 7x the subject of formula,
7x = 90-49
7x = 41
X =41/7
X = 5.86
Therefore, X = 5.86.
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because occurs without oxygen scientist believe this stage in cellular respiration evolved first
There are two sorts of cellular respiration: aerobic and anaerobic (see Concepts of Cellular Respiration). They can be known like this. One occurs within the presence of oxygen (aerobic) and also the other within the absence of oxygen (anaerobic). Both start with glycolysis - the breakdown of glucose.
Glycolysis (see the concept of "glycolysis") is an anaerobic process and doesn't require oxygen to continue. This process produces a minimal amount of ATP. The Krebs cycle and electron transport require oxygen, and within the presence of oxygen these processes generate far more ATP than glycolysis alone.
Scientists believe that glycolysis evolved before other stages of internal respiration. this can be because glycolysis doesn't require oxygen, whereas other stages require it. Also, when life first evolved about 3.5 billion years ago he was 4 billion years ago, and there was no oxygen within the Earth's atmosphere. respiration that happens without oxygen is named anaerobic respiration.
Then, about 2 to three billion years ago, oxygen was gradually added to the atmosphere by early photosynthetic bacteria (cyanobacteria). Organisms can then use oxygen to interrupt down glucose and make ATP. Most organisms today use oxygen to create ATP. They follow glycolysis with the tricarboxylic acid cycle and electron transfer to get more ATP than glycolysis alone. internal respiration that happens within the presence of oxygen is named aerobic respiration.
Therefore, the above statement is correct.
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a new mutation arises in the intron of a gene in a somatic cell. this mutation contributes to in the population by individuals in the next generation.
The new mutation which arises in the intron of the gene in the somatic cell. this mutation was contributes to the Variation in the population and it will not also be inherited by the individuals in the next further generation
Variation refers to the difference between the two individuals of the species. the Genetic variation arises due to the mutation and the recombination during the meiosis. Examples of the variation are different the skin colour, eys, the height, resistance to the diseases Variation is the difference in the genotypes also between the organisms of the same group. the Genetic variation is generated as the result of the processes such as the sexual reproduction, mutations in the DNA of sequence, and the gene flow in populations.
The question is actually incomplete, the complete question is:
A new mutation that arises in the intron of the gene in a somatic cell. This mutation contributes to the _____ in the population _____ by the individuals in the next generation.
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Which term describes a coupled transporter that moves both solutes in the same direction across a membrane?
The term Symport describes a coupled transporter that moves both solutes in the same direction across a membrane.
What is Symport?
Symport is a sort of transport in which two different molecules can pass across a membrane in the same direction by utilizing a similar carrier mechanism.
The transporter is referred to as a symporter and it functions in the cell membrane by simultaneously moving several molecules across the membrane.
One illustration is the transport of glucose up its concentration gradient with the assistance of the energy from the movement of sodium ions down its concentration gradient.
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How is it possible for a particular neurotransmitter to produce opposite effects in different tissues?
A neurotransmitter can bind to different types of receptors, each triggering a particular response in postsynaptic nerves.
What is a neurotransmitter?Your body cannot operate without chemical messengers called neurotransmitters. They are responsible for transporting chemical "messages" from one neuron (nerve cell) to the subsequent target cell. The following target cell may be a gland, muscle, or another nerve cell.
The nervous system in your body is a huge network of nerve cells that communicate electrical impulses between nerve cells and the cells they are intended to target. Your nervous system regulates the operation of your organs as well as everything from your intellect to your muscles.
In other words, your nerves have a role in everything you think, feel, and do. Your nerve cells transmit and receive data from every part of your body. The best possible functioning of your body depends on this ongoing feedback.
Therefore, by binding to different kinds of receptors, neurotransmitters can produce opposite effects in different tissues.
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The human nature level of personality analysis addresses how every human being is, in certain respects, ________.
The human nature level of personality analysis addresses how every human being is, in certain respects like all others.
What is the human nature?In psychology, the human nature has to do with the generality of the attitudes that make us human. This includes the ideologies and the tendencies that underlie our shared humanity.
Hence, the human nature level of personality analysis addresses how every human being is, in certain respects like all others.
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How do rats drink? While dogs form their tongues into spoons and scoop water into their mouths, scientists using high-speed video have shown that cats use a different technique to drink aqueous substances like water and milk. Four times a second, the cat touches the tip of its tongue to the water and draws a column of water up into its mouth (as you can see in the photo), which then shuts before gravity can pull the water back down. Describe how the properties of water allow cats to drink in this fashion, including how water's molecular structure contributes to the process.
The cat does not dip its tongue in the liquid. It just touches the surface. When touching the surface, there is an adhesive force that attracts water molecules to the surface of the cat's tongue. The cat then brings it back at a rapid pace, taking advantage of the inertia before gravity overcomes it and the water falls back into the bowl. Thus, the contribution of water molecules is in the adhesive force. The rest is the work of the cat's movement.
How does water's molecular structure allow cats to drink?The cat positions its mouth 3 cm above the water level (all cats use the same height). First, the tongue descends toward the water at a speed of up to 50 cm/s. After almost 50 milliseconds, the tip of the tongue, bent back, touches the surface of the water without penetrating it. The way a cat drinks liquid is credited to the two forces they need to balance: inertia and gravity.
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If you consciously forced more air out of your lungs each time you exhaled, how would that affect the values shown in the figure?
When you inhale (breathe), air enters your lungs, and the oxygen in that air flows to your blood. Carbon dioxide, a waste gas, flows from your blood to your lungs at the same moment and is expelled (breathed out).
What causes air to exit the lungs during forced expiration?The second step is exhalation, or breathing out. The diaphragm relaxes as the lungs evacuate, lowering the volume of the thoracic cavity while raising the pressure within it. The lungs tighten as a result, and air leaves.
Exhalation relaxes the diaphragm and causes it to return to its domelike shape, pushing air out of the lungs.
Exhaling causes your diaphragm to relax and move up into your chest cavity. Carbon dioxide-rich air is forced out of your lungs and windpipe, and then out your nose or mouth, as the space in your chest cavity reduces.
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Nadh and fadh2 carry high energy electrons from the other stages of respiration to the electron transport chain. What does the electron transport chain use these electrons to do?.
Some of the energy of the high-energy electrons is captured as they travel along the chains. This energy is used to move hydrogen ions (from NADH and FADH2) from the matrix into the intermembranous region through the inner membrane.
The last phase of aerobic respiration is electron transport. In this phase, energy from the Krebs cycle products NADH and FADH2 is converted to ATP.
NADH and FADH2 release high-energy electrons that travel through electron transport chains similar to those utilized during photosynthesis. The electron transport chains are located on the inner membrane of the mitochondrion. Some of the energy of the high-energy electrons is captured as they travel along the chains. Hydrogen ions (from NADH and FADH2) are pumped over the inner membrane and into the intermembrane space using this energy.
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How did ancient organisms change the Earth’s atmosphere?
Answer:
I will change everything on this earth and make it cool
9
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BUILD Vocabulary
lipid macromolecule made mostly
from carbon and hydrogen atoms;
includes fats, oils, and waxes
nucleotide subunit of which
nucleic acids are composed;
made up of a 5-carbon sugar,
a phosphate group, and a
nitrogenous base
nucleic acid macromolecules
containing hydrogen, oxygen,
nitrogen, carbon, and phosphorus
protein macromolecule that
contains carbon, hydrogen, oxygen,
and nitrogen; needed by the body
for growth and repair
amino acid compound with an
amino group on one end and a
carboxyl group on the other end
Related Words A polypeptide is
a chain of amino acids joined by
peptide bonds. A protein is made
up of one or more polypeptides.
Not all polypeptides are proteins.
How many levels of structure
are there in a protein with only
one polypeptide chain?
Answer: Carbon
It is often said that life is “carbon-based.” This means that carbon atoms, bonded to other carbon atoms or other elements, form the fundamental components of many, if not most, of the molecules found uniquely in living things. Other elements play important roles in biological molecules, but carbon certainly qualifies as the “foundation” element for molecules in living things. It is the bonding properties of carbon atoms that are responsible for its important role.
Carbon Bonding
Carbon contains four electrons in its outer shell. Therefore, it can form four covalent bonds with other atoms or molecules. The simplest organic carbon molecule is methane (CH4), in which four hydrogen atoms bind to a carbon atom.
Carbohydrates
Carbohydrates are macromolecules with which most consumers are somewhat familiar. To lose weight, some individuals adhere to “low-carb” diets. Athletes, in contrast, often “carb-load” before important competitions to ensure that they have sufficient energy to compete at a high level. Carbohydrates are, in fact, an essential part of our diet; grains, fruits, and vegetables are all natural sources of carbohydrates. Carbohydrates provide energy to the body, particularly through glucose, a simple sugar. Carbohydrates also have other important functions in humans, animals, and plants.
Carbohydrates can be represented by the formula (CH2O)n, where n is the number of carbon atoms in the molecule. In other words, the ratio of carbon to hydrogen to oxygen is 1:2:1 in carbohydrate molecules. Carbohydrates are classified into three subtypes: monosaccharides, disaccharides, and polysaccharides.
The chemical formula for glucose is C6H12O6. In most living species, glucose is an important source of energy. During cellular respiration, energy is released from glucose, and that energy is used to help make adenosine triphosphate (ATP). Plants synthesize glucose using carbon dioxide and water by the process of photosynthesis, and the glucose, in turn, is used for the energy requirements of the plant. The excess synthesized glucose is often stored as starch that is broken down by other organisms that feed on plants.
Chemical structures of glucose, galactose, and fructose.
Disaccharides (di- = “two”) form when two monosaccharides undergo a dehydration reaction (a reaction in which the removal of a water molecule occurs). During this process, the hydroxyl group (–OH) of one monosaccharide combines with a hydrogen atom of another monosaccharide, releasing a molecule of water (H2O) and forming a covalent bond between atoms in the two sugar molecules.
A long chain of monosaccharides linked by covalent bonds is known as a polysaccharide (poly- = “many”). The chain may be branched or unbranched, and it may contain different types of monosaccharides. Polysaccharides may be very large molecules. Starch, glycogen, cellulose, and chitin are examples of polysaccharides.
Starch is the stored form of sugars in plants and is made up of amylose and amylopectin (both polymers of glucose). Plants are able to synthesize glucose, and the excess glucose is stored as starch in different plant parts, including roots and seeds. The starch that is consumed by animals is broken down into smaller molecules, such as glucose. The cells can then absorb the glucose.
Glycogen is the storage form of glucose in humans and other vertebrates, and is made up of monomers of glucose. Glycogen is the animal equivalent of starch and is a highly branched molecule usually stored in liver and muscle cells. Whenever glucose levels decrease, glycogen is broken down to release glucose.
While the glucose-glucose bonds in cellulose cannot be broken down by human digestive enzymes, herbivores such as cows, buffalos, and horses are able to digest grass that is rich in cellulose and use it as a food source. In these animals, certain species of bacteria reside in the rumen (part of the digestive system of herbivores) and secrete the enzyme cellulase. The appendix also contains bacteria that break down cellulose, giving it an important role in the digestive systems of ruminants. Cellulases can break down cellulose into glucose monomers that can be used as an energy source by the animal.
Carbohydrates serve other functions in different animals. Arthropods, such as insects, spiders, and crabs, have an outer skeleton, called the exoskeleton, which protects their internal body parts. This exoskeleton is made of the biological macromolecule chitin, which is a nitrogenous carbohydrate. It is made of repeating units of a modified sugar containing nitrogen.
Thus, through differences in molecular structure, carbohydrates are able to serve the very different functions of energy storage (starch and glycogen) and structural support and protection (cellulose and chitin).