In the history of Earth and the evolution of cells, aerobic cells appeared first and anaerobic cells appeared later.
a. True
b. False

Answer:

Three treatments or reagents that causes protein denaturation are "heat", "urea" and "sodium hydroxide".

Explanation:

Heat: when a protein is exposed to elevated temperatures its molecules vibrate so rapidly and violently that its bonds are disrupted. This causes that the protein loses its tertiary and secondary structures and finally causes its denaturation.

Urea: a chemical denaturing agents that denatures proteins by lower the protein melting temperature which has a similar effect that high temperature. Urea compets for hydrogen bond donors and acceptors which affects the protein stability.

Sodium hydroxide: sodium hydroxide is an alkali agent that increases the pH value of the protein's solution. This results in removing hydrogen-bond contributing protons of the protein, which breaks its hydrogen bonds and causes its denaturation.

Answer:

(1) Conduction - (B) A seagull stands on ice and loses heat through its feet.

heat is lost due to direct contact.

(2) Free Convection - (E) A dog stands outside on a cold, but windless, day and loses heat to the air. There is heat transfer due to difference in temperatures.

(3) Forced Convection- (A) A bear stands in a cold flowing stream and loses heat to the water.  Here we consider buoyancy effects.

(4) Evaporation- An athlete sweats while running a race. water turns evaporates from the body taking a away heat.

(5) Radiation - (C) A lizard absorbs heat from the sun's rays. Sun´s heat travels as radiation.

Explanation:

Final answer:

The types of heat transfer are matched with their examples: (1) Conduction with (B) a seagull on ice, (2) Free Convection with (E) a dog losing heat to air, (3) Forced Convection with (A) a bear in flowing water, (4) Evaporation with (D) an athlete sweating, and (5) Radiation with (C) a lizard in sunlight.

Explanation:

The student has asked to match each type of heat transfer with the corresponding example. Here are the matches:

(1) Conduction: (B) A seagull stands on ice and loses heat through its feet.

(2) Free Convection: (E) A dog stands outside on a cold, but windless, day and loses heat to the air.

(3) Forced Convection: (A) A bear stands in a cold flowing stream and loses heat to the water.

(4) Evaporation: (D) An athlete sweats while running a race.

(5) Radiation: (C) A lizard absorbs heat from the sun's rays.

Each mechanism can be better understood by these everyday examples:

Conduction occurs when heat is transferred through direct contact, such as when you touch a hot stove.

Convection involves the movement of heat through a fluid (gas or liquid), like when warm air circulates in a room.

Evaporation is the process of a liquid turning into a vapor, taking heat away, like when wet clothes dry on a line.

Radiation involves the transfer of heat in the form of electromagnetic waves, such as sunlight warming your skin.

Answer:

The correct option is: c. a doorknob contaminated with the cold virus

Explanation:

Fomites are the inanimate objects or substances that can get contaminated with the pathogens and are capable of transferring the pathogens to the new hosts.

Sterilization of the possible fomites should be done in order to prevent cross-infection.

Examples of fomites are hair, towels, clothes, door knobs, cups, switches, handrails, remote controls, pens, syringes, bedding, etc.

Explanation:

A nerve impulse is a result of a difference in electrical charges across the plasma membrane of a neuron, this difference comes from ions which are electrically charged atoms or molecules.

Before the nerve impulse happens there's a resting potential in the neuron ready to transmit the impulse, this resting potential happens thanks to the sodium-potassium pump that uses ATP to pump Na+ out of the cell and K+ into it, resulting in the inside of a neuron negatively charged.

When a nerve impulse happens (thanks to the receiving of a chemical signal from another cell) a sudden reversal of the electrical charge of a resting neuron occurs, the inside of the neuron becomes positive when the gates in sodium channels open allowing positive sodium ions to flow back into the cell.

I hope you find this information useful! Good luck!

Answer: B. True

Explanation:

The tissue tropism can be define as the ability of the microbe to infect specific cells and tissues of the host that supports the growth of particular microbe like virus and bacteria.

Some viruses have broad tissue tropism they can infect many cell types. Other viruese can infect only single cell or tissue type.

Answer:

False.

Explanation:

Fatty acids may be defined as the carboxylic acid that contains the terminal carboxyl group and the hydrocarbon chain. Two types of fatty acid are saturated fatty acids and unsaturated fatty acids.

The unsaturated fatty acids contains double or triple bond in the fatty acids. The hydrogen are removed from the hydrocarbon chain and introduces double and triple bond in the fatty acids. A fatty acid with maximum number of hydrogen atom is saturated.

Thus, the answer is false.

Answer:

For calculating the surface to volume ratio for a spherical cell,  

Surface area (S) = 4πr²

Volume (V) = 4πr³ / 3

Ratio = S / V = 4πr² / 4πr³ / 3 = 3 × 4πr² / 4πr³

= 3/r

1. 15 micrometer diameter = Ratio = 3/7.5 = 0.4

2. 2 micrometer diameter = Ratio = 3/1 = 3

The cells exhibiting high surface to volume ratio shows enhanced metabolic activity. Shows easy uptake of oxygen, nutrients, water, and also the excretion of waste as they possess large surface.  

Final answer:

The surface-to-volume ratio for a cell with a 15 μm diameter is approximately 0.4:1, while the ratio for a 2 μm diameter cell is roughly 3:1. This difference implies that smaller cells have a higher efficiency for substance exchange due to a more favorable surface area relative to volume. Large cells may face limitations in diffusion, potentially leading to cell division or death if the cell cannot maintain sufficient exchange with its environment.

Explanation:

To calculate the surface-to-volume ratio of spherical cells, we use the formulas for the surface area (SA) and the volume (V) of a sphere. The surface area of a sphere is 4πr² and the volume is (4/3)πr³, with r being the radius of the sphere. For a cell with a diameter of 15 μm (radius = 7.5 μm) and a cell with a diameter of 2 μm (radius = 1 μm), we calculate as follows:

Surface-to-volume ratio for 15 μm diameter cell:
SA = 4π(7.5)2 ≈ 706.86 μm²
V = (4/3)π(7.5)3 ≈ 1767.15 μm³
Surface-to-volume ratio = SA/V ≈ 0.4:1

Surface-to-volume ratio for 2 μm diameter cell:
SA = 4π(1)2 ≈ 12.57 μm²
V = (4/3)π(1)3 ≈ 4.19 μm³
Surface-to-volume ratio = SA/V ≈ 3:1

Differences in surface-to-volume ratios have significant consequences for cell functions. A higher ratio means the cell has more surface area relative to its volume, which is advantageous for the diffusion of substances in and out of the cell. Smaller cells, with their higher surface-to-volume ratios, can therefore absorb nutrients and expel waste more efficiently than larger cells. However, as cells grow, their volume increases faster than their surface area, leading to a decreased surface-to-volume ratio, which can limit their ability to exchange materials and may trigger cell division or result in cell death if the cell becomes too large to maintain adequate exchange with the environment.

Answer:

The structure and function of DNA .

Explanation:

DNA is present as genetic material in almost all organism except some viruses. The DNA is made of pentose sugar, nitrogenous bases and the phosphate group.

The composition of the DNA remains same in almost all organism. Four nitrogenous bases of DNA are adenine, guanine, thymine and cytosine in almost all organism. The flow of genetic material and DNA replication occurs is similar in all the organisms. DNA shows unity among all the organism.

Thus, the correct answer is option (c).

The best representation of unity among all organisms is the structure and function of DNA due to its universal presence and role in defining biological structure and function across all life.

The best demonstration of the unity among all organisms is c. the structure and function of DNA. DNA, deoxyribonucleic acid, is consistent across all living organisms, acting as the instruction manual for cells and thus, overall biological structure and functionality. It unifies organisms as it is a universal code for life. Remarkably, despite the vast diversity of life on Earth, DNA serves as a fundamental similarity linking all forms of life. Each organism, from bacteria to blue whales, uses essentially the same mechanisms to read, interpret, and express DNA. This shared characteristic is a profound marker for unity among all organisms.

https://brainly.com/question/34857740

#SPJ3

Answer:

Let the "barred" allele be caller B and the "non-white" allele b. Since chickens use chromosomes [tex]Z[/tex]  and [tex]W[/tex] to determine sex, hens would have chromosomes [tex]ZW[/tex], and roosters would have chromosomes [tex]ZZ[/tex]. A Z-linked gene is represented as a superscript on the [tex]Z[/tex] chromosome, [tex]Z^{B}[/tex] for the dominant allele and [tex]Z^{b}[/tex] for the ressesive allele.

A barred hen would have a copy of B on its Z chromosome, a non-barred rooster would have both copies of b on both Z chromosomes. Using Punnet squares to represent the crosses we get the following cases:

[tex]\begin{center}\begin{tabular}{ |c|c|c|c| }\ & Z^{B} & W \\ \ Z^{b} & Z^{B}Z^{b} & Z^{b}W \\ \ Z^{b} & Z^{B}Z^{b} & Z^{b}W \\ \end{tabular}\end{center}[/tex]

That is a ratio of two barred heterozygote roosters to two non-barred hens. Crossing them we get:

[tex]\begin{center}\begin{tabular}{ |c|c|c|c| }\ & Z^{b} & W \\ \ Z^{B} & Z^{B}Z^{b} & Z^{B}W \\ \ Z^{b} & Z^{b}Z^{b} & Z^{b}W \\ \end{tabular}\end{center}[/tex]

That is a ratio of one barred heterozygote rooster to one barred hen to one non-barred rooster to one non barred hen.

For part a) crossing barred hen with  non-barred rooster produces 50% barred and 50% non-barred offspring of both genders. In part b) cross between their barred F1 offspring will again result in a mix of barred and non-barred offspring.

The barred feather pattern in chickens is a Z-linked dominant trait. In chickens, males have ZZ sex chromosomes, and females have ZW sex chromosomes.

(a) Cross of a barred hen (ZW) to a non-barred rooster (ZZ)

The barred hen has genotype [tex]Z^BW[/tex], and the non-barred rooster has genotype ZZ. The offspring will be:

(b) Cross of an F1 barred rooster ([tex]Z^BW[/tex]) to one of his barred sisters ([tex]Z^BW[/tex]) Since they both possess the barred trait, their genotypes are [tex]Z^BZ[/tex] and ([tex]Z^BW[/tex]), respectively. The offspring from this cross will be:

Answer:

a. True

Explanation:

Answer:

D) inner membrane is the correct answer.

Explanation:

ATP synthase located in the inner membrane of the mitochondrion.

ATP synthase has two subunits knowns as rotating subunit

that support in the  ATP generation by oxidative phosphorylation.

ATP synthase is an enzyme that produces adenosine triphosphate Which is called an Energy molecule.

ATP function is to provide energy to the cells.

ATP synthase is located in the inner membrane of the mitochondrion, which has folds called cristae to increase surface area for ATP synthesis.

The location of ATP synthase in the mitochondrion is within the inner membrane. This enzyme is crucial for the production of ATP (adenosine triphosphate), the cell's primary energy currency. The inner membrane of the mitochondrion contains folds called cristae, which increase its surface area and are integral to the function of the electron transport chain where ATP synthesis takes place. Therefore, the correct answer is D) inner membrane.

Answer:

Explanation:

The circulatory system, also called the vascular system or cardiovascular system. It consists of three important components such as heart or cardiovascular system, lungs or pulmonary system, vascular system such as arteries, veins and capillaries.

This system is responsible for the transport of gases, blood and nutrients to all the parts of the body. It helps in maintaining the homeostasis of the body  by stabilizing the pH, body temperature and fighting the diseases. Also maintains the balance of hormones.

Answer:

same DNA bases and HGT

Explanation:

Even though we are different species,  so much as different kingdoms, the DNA is always going to be the molecule that contains our genetic information and constitute our genes. This molecule is made up by the same structure: a sugar, a phosphate and a base like adenine, guanine, cytosine, thymine. Regardless if its a human, bacteria, fungi or a plant cell we all share this in common.

It is well known that we acquire our whole set of genes from our ancestors but some studies have shown that we also acquire genes from other organisms and its called horizontal gene transfer (HGT). HGT involves the movement of genetic material between different species. Since we've been sharing the world with a lot of prokaryotic organisms we might have experienced the HGT at some point of the evolution, and since our genetic material is made up of the same molecules, we can have the same subsets of genes working in both organisms.

Answer:

The subset of genes shared by humans and prokaryotes originates from a common ancestor and has been retained over billions of years of evolution.

Explanation:

This is was the right answer on my teachers test.

Answer:

D. Yes, abnormal proteins created by abnormal DNA is the problem in all genetic diseases.

Explanation:

DNA carries the information for the correct development and function of the human body. A gene is defined as a DNA fragment that codifies for a protein, this means that genes carry the information to shape a protein in the ribosomes. If the information is "corrupted" proteins can still be formed but can't work correctly.  

Answer: Catabolism

Explanation:

The addition of electrons to the compound is called as the reduction reaction. On the other hand, the removal of electrons is called as the oxidation.

The catabolism is a process by which electrons are removed from the compound. This is a oxidation reaction.The anabolism is a process by which electrons are added to the compound. This is the reduction reaction.

The anabolism is a process of formation of new complex substance from simple ones. This is a constructive process. The catabolism is a process of formation of simple substance from break down of complex ones. This is a destructive process.

Answer:

d. IgE

Explanation:

Immunoglobulin E (IgE) are antibodies that respond to allergic reactions. The response leads to the release of the anti-inflammatory histamine and vasoactive chemicals.

The researcher could look for the presence of proteins, because viruses have a envelope (capsid) composed of proteins that involve their genetic material. The capsid may have a helical or icosahedral structure and is extremely regular. Viroids cannot synthesize any type of protein, so differentiation is possible.

The microbiologist should look for the presence of protein to distinguish between the virus and the viroid, as only the virus will contain a protein coat.

The molecule the microbiologist should search for to distinguish between a virus and a viroid is protein. Viruses have a protein coat known as a capsid that encloses their nucleic acid core, which can be either DNA or RNA. Viroids, on the other hand, consist solely of a short strand of circular, single-stranded RNA without a protein coat. By analyzing the samples for the presence of protein, she can determine which is the virus (which has protein) and which is the viroid (which lacks protein).

Answer:

A

Explanation:

Hunger, fullness, and energy balanced are regulated by the hypothalamus. Hunger and fullness signals, in the form of hormones, travel through the bloodstream from tissues that consume energy to the brain. The hypothalamus is the region where these neuronal and hormonal signals integrate. After the reception of this signals the hypothalamus orchestrates a signaling cascade containing other hormones to create the hunger sensation.

Answer:

DNA polymerase.

Explanation:

DNA replication may be defined as the process of formation of daughter DNA from the template DNA strand. The process of DNA synthesis occurs in the 5' to 3' direction.

The enzyme responsible for DNA replication is DNA dependent DNA polymerase or DNA polymerase. This enzyme moves in 5' to 3' direction. DNA pol III is main replicating enzyme in prokaryotes and DNA pol alpha initiates DNA replication in eukaryotes.

Thus, the correct answer is option (a).

Answer:

The uncompetitive and mixed inhibitors are not affected by the substrate concentration while inhibition by a competitive inhibitor can be overcome by increasing the concentration of the substrate.

Explanation:

A competitive inhibitor competes with the substrate for the active site of the enzyme. When the competitive inhibitor combines with the enzyme and forms the enzyme-inhibitor complex (EI complex), the substrate cannot bind to the active site. However, the inhibition by competitive inhibitor can be overcome by increasing the substrate concentration around the enzyme which in turn would allow the substrate to bind to the active site and the reaction would proceed.  

On the other hand, an uncompetitive inhibitor binds to the site at the enzyme different from the active site. Once the ES complex is formed, the uncompetitive inhibitor joins the complex to inhibit the enzymatic activity.  

Likewise, a mixed inhibitor also occupies a site on the enzyme distinct from the active site for the substrate. A mixed inhibitor binds to the enzyme or ES complex to inhibit the reaction.  

Since the binding site for uncompetitive and mixed inhibitors are distinct from the substrate-binding site on the enzyme, increasing the substrate concentration can not overcome the inhibition.  

Answer:

A. Lipid A

Explanation:

The outer membrane of Gram-negative bacteria is present outside to the thin peptidoglycan layer. The outer membrane consists of lipopolysaccharide (LPS) which is the molecule having both carbohydrates and lipids.

The lipopolysaccharide has three parts out of which lipid A is the toxin one. Lipid A is embedded in the outer membrane through its fatty acids. When lipid A enters the blood stream of the host cell, it leads to septic shock. Lipid A is heat stable and highly toxic.

"The correct answer is the raccoons' population would decrease.

To understand the impact of a decreased mussel population on the ecosystem, one must consider the food web dynamics. Mussels are a food source for raccoons; therefore, if the mussel population were to decrease due to prolonged dry conditions, the raccoons would have less food available to them. This scarcity of food would likely lead to a decrease in the raccoon population due to starvation, reduced reproductive success, or the need to find alternative food sources which might not be as nutritious or abundant.

Freshwater mussels are filter feeders, which means they play a crucial role in their aquatic habitats by filtering water and removing pollutants, thereby maintaining water quality. A significant decrease in the mussel population could lead to deteriorating water quality, which might affect other aquatic organisms as well. However, the direct impact of the mussel population decline, as per the information provided, would be most immediately felt by their predators, in this case, the raccoons.

It is important to note that in a complex ecosystem, the effects of a population decline can be far-reaching and can affect multiple trophic levels. However, based on the information given and the direct predator-prey relationship mentioned, the population that would decrease as a result of the mussels' decline would be the raccoons."

Answer:

Null hypothesis may be defined as the any type of assumption in which the observed difference between two sample in the statistical population is accidental. Null hypothesis is used in the field of genetics as well.

If one accepts the null hypothesis this means that there is no significant differences between the observed values and the expected values of the experiment. The rejection of null hypothesis explains that there may be significant difference between the expected value and observed value.

Answer:

Antigenic variation is the change occurs in antigenic property of the pathogen. In antigenic variation, a pathogen does changes in its surface protein or carbohydrate so that the immune system of the host is not able to recognize the pathogen.  

This antigenic variation is very much beneficial to pathogens because it gives advantage to the pathogen to infect the host again and again without being recognized by immune cells and to increase in number.

A recombination of avian and human influenza virus in a host like pig created a new version of the influenza virus which became very endemic worldwide is a classic example of antigenic shift. M. tuberculosis evades immune response by doing antigenic shift it's membrane and cause tuberculosis.

Antigenic variation is the process by which pathogens alter their surface antigens to evade the immune system. Pathogens like HIV and Borrelia burgdorferi demonstrate antigenic variation.

Antigenic variation is the process by which pathogens alter the surface antigens in order to evade recognition by the host's immune system. It allows pathogens to escape from the immune response and continue to infect the host.

An example of a pathogen that demonstrates antigenic variation is the human immunodeficiency virus (HIV). HIV mutates rapidly, leading to constantly changing proteins on its viral envelope. By the time the adaptive immune system responds, the virus's antigens have already changed.

Another example of a pathogen that undergoes antigenic variation is the bacterium Borrelia burgdorferi, which causes Lyme disease. The bacterium's surface lipoprotein, VlsE, undergoes genetic recombination, leading to antigenic variation. This allows B. burgdorferi to evade the host's immune defenses.

Answer:

The answer is thymine.

Explanation:

RNA contains uracil but it does not contain thymine. DNA contains thymine. Both have adenine, cytosine, and guanine.

Answer:

Which type(s) of cell division reduce(s) the chromosome number by half?

                           Meiosis l

Which type(s) of cell division can be classified as reductional?  

                            Meiosis I

Which type(s) of cell division can be classified as equational?

                           Mitosis and Meiosis II

Explanation:

Meiosis is a type of cell division which occurs in the germ or reproductive cells to produce gametes. It is completed in the two stages, meiosis I and meiosis II.  The cells which are going to divide by meiosis are diploid having two sets of chromosomes. Meiosis I is the first stage of the meiosis. At the end of meiosis I two daughter cells are formed having only 1 set of chromosomes and chromosome numbers are reduced to half. Thus, meiosis I is a reductional division.  

Mitosis and meiosis II is the equational division as after division chromosome number remains the same as in the parent.  

Answer:

b) glycolisis

Explanation:

Glycolisis precedes the Krebs cycle and can take place under aerobic or anaerobic conditions. Under aerobic condition, energy is directed towards the Krebs cycle in the form of piruvate and NADH to create more ATP. Under anaerobic conditions piruvate does not enter the Krebs cycle and it is oxidized to produce lactate.

Answer:

Well, there can be various causes of not finding any cells while examining a slider under the microscope. Some of them are as follows:  

a. The light of the microscope might be switched off and the slide does not comprise any cells.  

b. The microscope is not focused appropriately so that one can witness the cells.  

c. The region of the slide comprising the cells is not coming in the field of vision.  

d. The magnification of the microscope is not appropriate, that is, either it is very low or is very high.  

e. Destruction of the sample would have taken place.  

Answer: True. Selective media can be used to separate gram negative from gram positive bacteria.

Explanation: Selective media allow certain types of organisms to grow, and inhibit  the growth of other organisms.

For example: Media containing potassium  tellurite will  inhibit the growth of gram negative bacteria while media supplemented with penicillin will inhibit the growth of gram positive  bacteria.

Answer:b. Certain proteins are unique to each membrane.

Explanation:

Cell membranes of the eukaryotes are composed of proteins and lipids. The membranes of the eukaryotic cells are composed of lipid bilayers associated with the proteins. The proteins may differ in composition depending upon the type of cell. The membrane proteins act like a signal sequences to target other proteins to respective destinations to perform desired functions. Therefore, option B is correct.

Proteins vary amongst different membranes in a eukaryotic cell, as they are specifically distributed to carry out specialized functions related to their respective location within the cell.

The membranes of a eukaryotic cell can vary in several ways, but the most accurate answer to your question would be option b: 'Certain proteins are unique to each membrane'. This is because, although all membranes contain phospholipids and are amphipathic, different proteins are embedded within these phospholipid layers based on the specific functions they serve in different parts of the cell, allowing them to carry out specialized tasks. These can range from transport proteins in the cell membrane that regulate the passage of substances, to proteins in the mitochondrial membrane involved in energy production. Therefore, the variation in proteins is what truly distinguishes different cellular membranes within a eukaryotic cell.

https://brainly.com/question/32921743