How many bacteria, I micron on each side, will fit in a typical human cell (about 25 microns on each side)?

Although it is not necessary to do so, we can make a simplifying assumption that both human cells and bacterial cells have the shape of cubes. Since the bacterial cells are I /25th the length of the human one, as many as 25 x 25 x 25 will fit inside. (Picture a large cube and start stuffing it with the little ones, 25 rows of 25 on the bottom layer, and 25 such layers); 25 x 25 x 25 =15,625. Since we are estimating, we should round off to about 16,000. We will later see that this consideration of bacterial cells fitting within human cells is not without significance, both in terms of mitochondria and chloroplasts and in terms of our immune systems.

What is Molecular Motors?

Organisms, from human beings to bacteria, move to adapt to changes in their environments, navigating toward food and away from danger. Cells, themselves, are not static but are bustling assemblies of moving proteins, nucleic acids, and organelles. In fact, many of the proteins that play key roles in converting chemical energy in the form of ATP into kinetic energy, the energy of motion, are members of the same protein family, the P-loop NTPases. These molecular motors are homologous to proteins, including the G proteins in protein synthesis, signaling, and other processes. Molecular motors operate by small increments, converting changes in protein conformation into directed motion. The motor proteins cycle between forms having high or low affinity for the filament tracks in response to ATP binding and hydrolysis, enabling a bind, pull, and release mechanism that generates motion.

Why Biostatistician?

Biostatisticians are statisticians who work in health-related fields. They design research studies and collect and analyze data on problems — such as how a disease progresses, how safe a new treatment or medication is, or the impact of certain risk factors associated with medical conditions. They may also design and analyze studies to determine health care costs and health care quality. They are instrumental in the designing stages of studies, providing expertise on experimental design, sample sizes, and other considerations.

CAM Photosynthesis

Another “add-on” feature to C3 photosynthesis is crassulacean acid metabolism (CAM).The physiology of this pathway is almost identical to C4 photosynthesis, with the changes that follow:
1. PEP carboxylase still fixes CO2 to OAA, as in C4. Instead of malate, however, OAA is converted to malic acid. (This is a minor difference, since malate is merely the ionized form of malic acid). 2. Malic acid is shuttled to the vacuole of the cell (not moved out of the cell to bundle sheath cells as in regular C4). 3. Stomata are open at night. During the night, PEP carboxylase is active and malic acid accumulates in the cell’s vacuole. 4. Stomata are closed during the day (the reverse of other plants). At this time, malic acid is shuttled out of the vacuole and converted back to OAA (requiring 1 ATP to ADP), releasing CO2. The CO2 is now fixed by rubisco, and the Calvin-Benson cycle proceeds. The advantage of CAM is that photosynthesis can proceed during the day while the stomata are closed, greatly reducing H2O loss. As a result, CAM provides an adaptation for plants that grow in hot, dry environments with cool nights (such as deserts). The name crassulacean acid metabolism comes from the early discovery of CAM in the succulent plants of the family Crassulaceae and the discovery of the accumulation of malic acid in vacuoles during the night. In addition to the Crassulaceae, CAM is found among plants in over a dozen different families, including cacti.

You know about Protein folding?

Folding occurs step-wise with several intermediates unfolded/secondary structure/domains/molten globule/native tertiary structure. The steps include, a collapsed structure (molten globule) occurs very quickly. steps between molten globule and native tertiary structure usually occur slowly (a) intermediates are isolatable (b) multiple pathways are possible. Folding is driven by hydrophobic forces. Proteins can self assemble but in vivo folding is facilitated by proteins. Chaperones are binding proteins which assist folding (a) chaperones cause misfolded protein to unfold rather than aggregate (b) many chaperones require ATP hydrolysis for activity (c) more than one chaperone may act simultaneously and sequentially in the folding of a single protein (d) chaperones are specific for specific protein synthesis pathways (cytosolic vs. mito. vs. endoplasmic reticulum). Enzymes catalyze kinetically slow steps infolding (a) cis-trans prolyl isomerase (i) both cis and trans peptide bonds to proline naturally occur (ii) the isomerization of peptidyl-proline bonds may be slow (b) protein disulfide isomerase (i) catalyzes disulfide bond formation and isomerization. Denaturation is unfolding 1. Requires some input to overcome hydrophobic forces (a) heat (b) denaturant (urea or guanidinium) and requires reductant to reduce disulfide bridges to sulfhydryls.

How many pounds of ATP is recycled in the body?

Fortunately, ATP is recycled within the body. The typical daily requirement for an adult is over 140 pounds of ATP per day. However, the amount of ATP present in our body at any one time is only about one-tenth of a pound. That means each ATP molecule in our body is recycled about 1,400 times each day. Now that is effective recycling — and we don’t even have to put anything into a blue container.

How to determine whether a solution is acidic or basic using a food ?

Red cabbage may be used to determine whether a solution is acidic or basic.Red cabbage contains a pigment called flavin (an anthocyanin). This water soluble pigment is also found in apple skin, plums, poppies, cornflowers, and grapes. Very acidic solutions will turn anthocyanin a red color. Neutral solutions result in a purplish color. Basic solutions appear in greenish-yellow. Therefore, it is possible to determine the pH of a solution based on the color it turns the anthocyanin pigments in red cabbage juice. To prepare a solution of red cabbage juice indicator, chop some red cabbage into small pieces and cover them with boiling water. Allow the mixture to sit for approximately ten minutes. The indicator may now be used to test various solutions as to their acidity.

How much will it cost to synthesize AMP and GMP?

The biosynthesis of both AMP and GMP requires the hydrolysis of several high-energy bonds. To produce IMP from D-ribose 5-phosphate requires the hydrolysis of five high-energy bonds (one PPi and five ATP). To convert IMP to AMP requires the hydrolysis of one more high-energy bond (from GTP). And to convert IMP to GMP requires the hydrolysis of two high-energy bonds — one ATP and one PPi. Anaerobic organisms, such as the bacteria responsible for tetanus or botulism, must oxidize four glucose molecules at two ATP per glucose to meet the energy requirement. An aerobic organism, like you, for example, needs to oxidize only one glucose molecule at 36 or 38 ATP per glucose. The preceding processes require a substantial amount of energy. Sometimes this energy requirement may be lessened by metabolic processes known as the salvage pathways. In the salvage pathways, nitrogen bases are recycled instead of synthesized. The nitrogen bases are then converted to nucleotides.

What happens if you stop eating?

Starvation is the total deprivation of food. Here is what happens during starvation: Initially, the body utilizes its glycogen reserves. Then it moves on to its fat reserves — the first ones are those around the heart and kidneys. Finally, the body relies on the reserves found in the bone marrow. Early in a total fast, the body metabolizes protein at a rapid rate. The amino acids are converted to glucose, because the brain prefers glucose. These proteins come from the skeletal muscles, blood plasma, and other sources in a process that produces a quantity of nitrogen-containing products, which need to be excreted. Excretion requires large quantities of water, and the resulting loss of water may lead to death by dehydration. If the starvation continues, the brain chemistry adjusts to accept fatty acid metabolites, which uses the last of the fat reserves. Finally, the body resorts to structural proteins, systems begin to fail rapidly, and death follows quickly.

How can diseases be transmitted among various individuals?

In order for transmission among individuals to occur, the pathogenic microorganisms must leave the body through a portal of exit. Transmission can occur in the form of respiratory secretions expelled from the respiratory tract, or microorganisms can exit in the feces or urine, or they may be removed when blood is ingested by mosquitoes, ticks, or other arthropods. Skin contact, including contact made during sexual intercourse, is another mechanism for transport to the next individual.

Are prokaryotes and eukaryotes similar in any respects?

Prokaryotes and eukaryotes share common features, among them the possession of nucleic acids and other organic substances such as proteins, carbohydrates, and lipids. In addition, they utilize similar metabolic reactions such as glycolysis and chemiosmosis for the utilization of food and the production of energy and waste. Also, they exhibit many of the same physiological features such as motion and reproduction, although the mode of reproduction may be different and different organs of motility may exist.

How is resolution determined in microscope?

To determine resolution, one must know the numerical aperture (NA) of the lens system. This denotes the size of the cone of light entering the aperture of the lens. The NA, typically etched into the lens, is multiplied by two. The product is then divided into the wavelength of the visible light, typically 550 nm. (If another form of light such as ultraviolet light were used, the wavelength of that light would be used in the formula.) The result is the resolution of the lens system expressed in nm. Conversion to micrometers is usually the final step.

What is bulimia?

Bulimia is an eating disorder in which individuals binge eat frequently—often several times a week or even several times per day. Sufferers of this illness may eat an enormous amount of food in a short time, consuming thousands of calories. Then they will purge their bodies by vomiting or using laxatives and/or diuretics.

What is diapedesis?

Diapedesis is the ability of white blood cells to squeeze between the cells that form blood vessel walls. Once these white blood cells are outside the blood, they move through interstitial spaces using a form of primitive movement called amoeboid motion. Neutrophils and monocytes are the most active of these white blood cells. These leukocytes engulf bacterial cells, organic molecules in bacterial cells, and other large objects such as parasites. Neutrophils and monocytes frequently become so full of bacterial toxins and other related products that they also die.

How is the skin involved in the regulation of body temperature?

The skin is one of several organ systems participating in maintaining a core temperature, meaning the temperature near the center of someone’s body. Temperature sensors in the skin and internal organs monitor core temperature and transmit signals to the control center located in the hypothalamus, a region of the brain. When the core temperature falls below its set point, the hypothalamus: 1. Sends more nerve impulses to blood vessels in the skin that cause the vessels to narrow, which restricts blood flow to the skin, reducing heat loss. 2. Stimulates the skeletal muscles, causing brief bursts of muscular contraction, known as shivering, which generates heat. When the core temperature rises above its set point, the hypothalamus: 1. Sends fewer nerve impulses to blood vessels in the skin, causing them to dilate, which increases blood flow to the skin and promotes heat loss. 2. Activates the sweat glands, and when sweat evaporates off the skin surface it carries a large amount of body heat with it.

What are three components necessary to maintain homeostasis?

The three components of homeostasis are sensory receptors, integrators, and effectors. These three components interact to maintain the state of homeostasis. Sensory receptors are cells that can detect a stimulus that signals a change in the environment. The brain is the integrator that processes the information and selects a response. Muscles and glands are effectors that carry out the response

What are the effects of Ageing on respiratory system?

There is a decline in the efficiency of the respiratory system with ageing. There is a gradual loss of elastic tissue & the chest wall becomes less capable of expansion. These changes show up as a reduction in vital capacity (The maximum volume of air that can be expired after a maximum inspiration). This may decrease by as much as 35% by the age of 70. All other aspects of function decline in performance notably, the action of cilia & protective activity of white blood cells. This leaves the system more prone to disease like pneumonia, bronchitis & emphysema.

How does blood circulate in the fetus?

Fetal circulation differs from circulation after birth because the lungs of the fetus are nonfunctional. Therefore, blood circulation essentially bypasses the lungs in the fetus. The umbilical vein carries oxygenated blood from the placenta to the fetus. About half of the blood from the umbilical vein enters the liver, while the rest of the blood bypasses the liver and enters the ductus venosus. The ductus venosus joins the inferior vena cava. Blood enters the right atrium of the heart and then flows through the foramen ovale to the left atrium. Blood then passes into the left ventricle (lower portion of the heart) and then to the aorta. From the aorta, blood is sent to the head and upper extremities. It returns to the right atrium of the heart through the superior vena cava. Some blood stays in the pulmonary trunk to reach the developing lung tissues.

What are the benefits of breastfeeding?

Breastfeeding provides benefits to both the baby and the mother. A major benefit to the baby is that breast milk supplies the correct amount of nutrients as the baby grows from an infant to a healthy toddler. The nutrients in breast milk also protect the infant from certain childhood illnesses. Finally, recent research has shown that breast milk contains certain fatty acids (building blocks) that help the infant’s brain develop. In the early days following childbirth, the mother’s body releases a hormone that makes her uterus contract and get smaller in response to the baby’s sucking. Breastfeeding also provides many emotional benefits between mother and child and encourages maternal-infant bonding. Human breast milk consists of mostly of water (88 percent), sugars (6.5 to 8 percent), lipids (3 to 5 percent), proteins (1 to 2 percent), amino acids, and salts. It also contains large quantities of lysozymes—enzymes with antibiotic properties. Human milk is bluish-white in color and sweet. The blue color comes from the protein and the white comes from the fat. There are approximately 750 calories per liter of breast milk.

Why is carbon so important in biological system?

It is sometime said that life on our planet is based on carbon. Carbon is an element that is found in all organic molecules. Carbon forms strong covalent bonds, in other words it shares electrons, with other elements. It forms four such bonds that are it has a valency of four. A simple example is methane, whose molecular formula is CH4. The explanation for the importance of carbon lies in the way carbon atoms can join to each other, forming either chain or rings. These chains & rings are the skeletons of organic molecules & hence of life itself. They are very stable because the covalent bonds linking the carbon atoms together are strong. Atoms or particular groups of atoms of other elements (referred to simply as groups) can be attached at various positions to the carbon skeleton.