Which pair of structures would provide a positive identification of a plant cell under a microscope?
(a)ribosomes, chloroplasts
(b)cell wall, chloroplast
(c)plasma membrane, large central vacuole
(d)cell wall, mitochondria
Answer:
The correct option is Option B i.e. cell walls and chloroplasts.
Explanation:
1. The plant cells differ with the animal cells with respect to some points.
2. Firstly, the presence of cell walls are exclusive for plants and totally absent in animals.
3. Secondly, the presence of chloroplasts or plastids is exclusive for plants.
4. Thirdly, vacuoles are huge in plant cells, but smaller in animals. They give extra support to each cells for standing, and also to store several excretory products.
The pair of structures that would provide positive identification of a plant cell under a microscope are cell wall and chloroplast (Option b).
Plant cells have a cell wall mainly composed of a complex carbohydrate called cellulose.
This structure (cell wall) provides structural support to plant cells.
Moreover, plant cells also have an organelle known as chloroplast, which serves to synthesize simple carbohydrates (sugars) by a process known as photosynthesis.
In conclusion, the pair of structures that would provide positive identification of a plant cell under a microscope are cell wall and chloroplast (Option b).
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When you are exposed to sunlight for a long time, your skin, which otherwise appears normal, gets heavily tanned. What could be the reason?
Answer:
Our skin gets tanned by getting exposed to sunlight due to the production of melanin as a protective measure.
Explanation:
Electromagnetic waves like infrared waves and UV rays are present in sunlight. While infrared rays maintain the earth’s atmospheric heat UV rays doesn’t prove to be helpful. UV rays that penetrate the skin damages the DNA and RNA .
The body has developed a fighting mechanism to tackle this problem. That method is the production of melanin, which is the colouring pigment in human skin. The melanin reduces the penetration of UV rays into the skin.
Anna heated 15 g of Substance A to obtain 5 g of substance B, 4 g of Substance C, and a certain amount of Substance D, which statement is correct
A) the mass of substance D was 10g less than the mass of substance A
B) the mass of substance D was 1 g greater than the mass of substance B
C) the mass of substance A was equal to the total mass of substance C and substance D
D) the mass of substance A was equal the the total mass of substance B and substance D
Answer:
I think its B
Explanation:
What is the role of chlorophyll in photosynthesis
Chlorophyll captures light energy from the sun to produce glucose
You set up 5 samples that contained a range of sucrase concentrations but the same amount of
substrate (sucrose)
- The pH was kept constant in all tubes by using the same amount of buffer
- The temperature was kept constant in all tubes (room temp)
- A negative control was used (without the substrate sucrose) to prove that this reaction is due to enzyme activity. It is important
to establish this, because sucrose can break down on its own to yield glucose and fructose but this reaction would take much
longer without enzyme
- There was no quantitative data, but a color key was used to distinguish between maximum, medium and low enzyme activity
- By graphing the qualitative data, you observed that the reaction increases as the enzyme concentration is increased. This
means, the more enzyme, the more sucrose can be broken down, the more products can be formed.
- However this effect can be observed up to a limit.
As stated, the results as evidenced in the experiment can only be observed up to a limit. Why?
A buildup of sugars alters the pH of the environment
The products, glucose and fructose, denature the sucrase
You eventually run out of sucrose to act as the substrate
The reaction causes a change in temperature, that denatures the sucrase.
Eliminate
Answer:
You eventually run out of sucrose to act as the substrate.
Explanation:
You must have both substrate and an enzyme for the reaction to continue.
Enzyme activity increases with the concentration of sucrase up to a point. This limit is due to the finite amount of sucrose in the system. Once all sucrose is utilized, the reaction stops regardless of enzyme concentration.
Explanation:The results of the experiment you conducted can only be observed up to a limit due to the fact that there is a finite amount of substrate (in this case, sucrose) available in the system. The enzyme sucrase functions by breaking down the substrate sucrose into glucose and fructose. As the concentration of sucrase increases, more sucrose can be broken down at a faster rate, which increases the reaction speed. However, once all the sucrose has been utilized, the reaction will stop regardless of the enzyme concentration as there is no more substrate for the enzyme sucrase to act upon. Hence, the increase in enzyme activity is observed only up to a certain limit.
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3. Which is true about a valid scientific hypothesis?
a. It is the same as a scientific theory.
b. It is a testable statement.
c. It can be scientifically proved to be true.
d. It is never rejected.
Answer:
The answer Is B.
Explanation:
A hypothesis is a suggested solution for an unexplained occurrence that does not fit into current accepted scientific theory. ... For a hypothesis to be termed a scientific hypothesis, it has to be something that can be supported or refuted through carefully crafted experimentation or observation.
pressure is a force defined as?
a. The movement of particles in matter
b. The number of particles in an object
c. a pull that is related to buoyancy
d. a push the acts over a certain area
which of the following is the best example of homeostasis in the human body? and why?
Answer:
Basically, the tendency to maintain a stable, relatively constant internal environment is called homeostasis. The body maintains homeostasis for many factors in addition to temperature. For instance, the concentration of various ions in your blood must be kept steady, along with pH and the concentration of glucose.
Explanation:
Why roots need to use different methods to absorb water and ions?
Final answer:
Roots need different methods to absorb water and ions due to their different properties. Water is absorbed through root hairs, while ions are absorbed by thin-walled epidermal cells and root hairs, as well as through a mycorrhizal relationship with fungi.
Explanation:
Roots need to use different methods to absorb water and ions because water and ions have different properties and require different mechanisms for uptake. Roots absorb water through root hairs, which are extensions of root epidermal cells that increase the surface area of the root for efficient water absorption.
Water moves through the permeable cell walls of the root epidermis and diffuses into the root cortex. On the other hand, ions (nutrients) are absorbed by thin-walled epidermal cells, root hairs, and a mycorrhizal relationship with fungi. Root hairs are especially important for nutrient absorption.
Plants need both water and minerals, which they absorb via different methods. Water is absorbed through osmosis, while minerals use active transport requiring energy. These distinct processes are essential due to the differing properties of water and ion absorption.
Plants need both water and minerals to survive. They use different methods to absorb each type of nutrient due to the distinct properties of water and minerals.Absorption Methods:
Water is absorbed through a process called osmosis where it moves from a region of higher concentration (soil) to a region of lower concentration (inside root cells).Minerals or ions are absorbed through active transport, which requires energy because these nutrients often move from a region of lower concentration (soil) to a region of higher concentration (inside root cells).Different methods are necessary because water naturally moves to balance concentration levels via osmosis, while minerals require energy to move against their concentration gradient.HELP!! dihybrid crosses
Answer:
Predicting the genotype of offspring . Determine all possible combinations of alleles in the gametes for each parent. Half of the gametes get a dominant S and a dominant Y allele; the other half of the gametes get a recessive s and a recessive y allele. Both parents produce 25% each of SY, Sy, sY, and sy.
Explanation:
This is an example of how you complete the problem. I hope this helps! :)
A dihybrid cross is a breeding experiment that shows how two distinct traits are passed from parents to offspring. It's done using a Punnett square to determine the probability of offspring combinations.
Explanation:A dihybrid cross is a breeding experiment that involves parents that differ in two distinct, genetically determined traits. In the study of genetics, The aim of a dihybrid cross is to determine the likelihood of offspring inheriting combinations of traits from their parents.
For instance, let's consider an example of crossing two pea plants. One possesses the traits for being tall with yellow seeds (TTYY) and the other being short with green seeds (ttyy). We can observe a dihybrid cross to predict the progeny's traits.
To do so, a Punnett square is used to visualize all the potential combinations of gametes resulting from meiosis. Later, these combinations can be analyzed to find out the probability of an offspring manifesting a certain combination of traits.
In short, dihybrid crosses provide a systematic method to study how traits are passed on to offspring generation. Its findings are fundamental to understanding the principles of genetics.
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PLZ HELP ME I NEED IT CAUSE I SUCK AT SCI!!! After a town is abandoned, the concrete parking lots remain empty and inactive for hundreds of years. What is the most likely order of ecological succession in that area?
A.grass → trees → lichens → moss
B.lichens → grass → shrubs → trees
C.lichens → grass → trees → shrubs
D.shrubs → grass → trees → lichens
Answer: B
Explanation:
Would be last, wouldn’t they? That would make the most sense to me.
Answer:
Option (B).
Explanation:
Succession may be defined as the change in the ecological community of the species with respect to time. Two main types of succession are primary succession and secondary succession.
The living things that accumulate in the succession is from the simple organism to the complex organism. First lichens will evade in the land. After lichens grass then shrubs and finally the trees will cover the area and convert into the forest.
Thus, the correct answer is option (B).
A food business such as a restaurant must be certain to purchase their food products from a _______ source.
Answer:
Reputed
Explanation:
A food source is reputed because it sells original food products and also that is not stale.
In a restaurant, if the food products should be purchased from a reputed source as it will ensure that the items are not stale and also the customers will be happy to know that the food that is being served to them is not made of rotten items and also collected from a renowned source. Thus, the purchase also increases.
Photosynthesis has two main parts (light-independent and light dependent). Which descriptions can BEST be used to explain photosystem I and photosystem II? I. Light-independent reaction II. Light-dependent reaction III. Products are ATP and NADPH. IV. Occurs in the thylakoid membranes V. Occurs in the stroma VI. Photolysis of water occurs during this stage. A) I, V, and VI B) I, IV, V, and VI C) I, II, III, and V D) II, III, IV, and VI
Answer:
D
Explanation:
In photosystems, the reactive center gives of an electrons that are conveyed along a chain of pigments that harness the energy of the electrons to pump H+ ions from the stroma into the thylakoid – hence creating a proton motive force that will be used to generate ATPs by ATP synthase enzyme. Eventually the electrons are passed to NADP+ that is reduced to NADPH (2 electrons per molecule). The photolysis of a water molecule by sunlight gives H+ and O- and 2 free electrons used to replace the lost electrons in the photosystems reactive center. This whole process is referred to as photophosphorylation.
Answer:
Option D explain the photo system I
Explanation:
In a light independent reaction, light energy from sun is essential to carry out photosynthesis and produce energy molecules such as ATP and NADH. These reactions take place within the thylakoid membrane of chloroplasts. When the sunlight from the sun is taken by the green leaves of the plant it is initially used to break down the water molecules that releases free electron
Hence, option D is correct
What are four functions of cell division?
Answer:
(1) the reproduction of an entire unicellular organism,
(2) the growth and repair of tissues in multicellular animals,
(3) the formation of gametes (eggs and sperm) for sexual reproduction in multicellular animals.
Explanation:
what are the main functions of polysacchrides in plants
Answer:
protein and energy
Explanation:
if you look close at the wall of a plant it has cellulose and hemicellulose.
Answer:
Explanation:
It is stored in the carbon atoms
Where do most human inputs of outdoor air pollutants occur?
in the mountains
around oceans
in deserts
in urban areas
Answer:in urban areas let me know if i was right or wrong
Explanation:
Answer:
in urban areas is the correct answer.
Explanation:
most human inputs of outdoor air pollutants occur in the urban areas.
its occur in the urban areas because of the following reasons
In the urban areas, people are more depended on cars, vehicles and chemicals industries that are there which give rise to outdoor air pollutants.burning of fossil fuels in the power factory, in a machine vehicle and the industrial plants, generate large outdoor pollutants in the urban areas.63. A student wanted to determine if slugs preferred green leaf lettuce
leaves over purple cabbage leaves for food. Pieces of both leaves
were cut. One piece of each type of leaf and one slug were placed in
each often containers. After three days, the surface area of each leaf
section was measured and the results were recorded in a data table.
State one reason that the results of this experiment might be considered
Invalid.
The result might be considered invalid because:-
The time interval was not recorded when the slugs were placed.An experiment should be performed various time to consider a result. What to do while performing an experiment?Ask a question based on observation. Make observations. Refine hypothesis. Select a specific variable to test.Pick a control group.Conduct tests.Continue tests.To know more about hypothesis here
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What are the main types of Star clusters?Check all that apply.
Answer:
The three basic types of clusters astronomers have discovered are globular clusters, open clusters, and stellar associations. ...
Globular clusters were given this name because they are nearly symmetrical round systems of, typically, hundreds of thousands of stars. ...
Open clusters are found in the disk of the Galaxy.
Answer:
The star clusters are defined as the enormous groups of stars. The three major types of clusters are as follows-
(1) Globular clusters- They are almost symmetrical and forms a circular type of system. They are many hundreds and thousands of stars. The surface temperatures of these stars are approximately 4000 K. These stars represent the oldest portion of the Milky Way Galaxy. Here, the stars are closely oriented due to the high gravitational force.
(2) Open clusters- These include stars of different ages and are mostly present in the disk of the Galaxy. These stars are comparatively younger than the globular clusters and have a diameter of less than about 30 light-years. Here, the stars are not closely oriented, whereas they are scattered as a result of which they are named as the open clusters.
(3) Stellar associations- These stars are about 100–500 light-years in terms of diameter. The stellar association is a bunch of very young stars that contains about 5 to 50 hot and bright Orange as well as Blue stars are scattered over a specific boundary in space.
What are the main functions of DNA polymerase?
DNA polymerases are critical for DNA replication, ensuring the synthesis of new DNA strands, proofreading to correct errors, and exhibiting high processivity. They also have specialized functions such as removing RNA primers and initiating DNA replication.
DNA polymerases are essential enzymes in the process of DNA replication, performing several critical functions to ensure the accuracy and completeness of DNA synthesis.
Main Functions of DNA Polymerase
DNA synthesis: DNA polymerase catalyzes the incorporation of deoxynucleotides into a growing DNA strand, following the template DNA strand to create a new complementary strand.Proofreading: To maintain high fidelity during DNA replication, DNA polymerase possesses proofreading activity, using its 3' to 5' exonuclease function to correct errors by removing mispaired nucleotides.Processivity: The enzyme’s ability to rapidly synthesize long strands of DNA without frequently dissociating from the DNA template is termed processivity, which is crucial for efficient replication.Specific DNA polymerases also have unique roles, such as the removal of RNA primers by DNA polymerase I, whereas DNA polymerase III is the main functional polymerase at the replication fork in E. coli. In eukaryotes, like humans, DNA polymerases δ and ε perform the majority of replicative functions, with DNA polymerase α initiating replication.
Which of the following types of models is generally used to predict long-term events?
a. idea model
b. physical model
computer model
d. none of the above
Please select the best answer from the choices provided
Computer model is generally used to predict long-term events
Answer: C. Computer model
Explanation:
Scientific models are used to predict and elaborate the behaviour of the real objects in the field of physics, chemistry, ecology and earth science. Computer model is the type of scientific model that is used to explain long term events.
A computer model is used to follow patterns of the weather along with the factors to forecast natural events. It is not the only type of model to make predictions.
For instance, predicting earthquake uses computer model, relationship between time and distance is the idea model, study of cell and its various parts uses physical model.
Answer:
C is the answer
Explanation:
I just took the test
Do all cells undergo Mitosis frequently? Why or why not?
Not all cells undergo mitosis frequently. The frequency varies depending on the type of cell and its role in the organism. While some cells divide regularly, others like neurons or cardiac muscle cells do not divide, spending their lifetime in the Go phase.
Explanation:No, not all cells undergo mitosis frequently. The frequency of cell division is highly variable even within the cells of a single organism. For instance, in humans, the frequency of cell turnover ranges from a few hours in early embryonic development, to an average of two to five days for epithelial cells. However, certain specialized cells, such as cortical neurons or cardiac muscle cells, spend an entire human lifetime in the Go phase without dividing.
Mitosis is the process by which a cell divides to produce two genetically identical daughter cells. This cell division process is comprised of four major stages - prophase, metaphase, anaphase, and telophase - and is typically followed by cytokinesis, which divides the cytoplasm of the cell. This process occurs in all normally dividing cells of the body except for germ cells that produce eggs and sperm, which instead undergo meiosis for sexual reproduction.
Cells produced through mitosis serve various functions in different parts of the body, such as growth, replacing dead or damaged cells, and even asexual reproduction in some organisms.
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Which cell component functions like the bones and muscles in the human body?
cytoskeleton
chloroplasts
cytoplasm
ribosomes
Cytoskeleton - I mean, it literally has the word *Skeleton* in the name.
Elements are pure substances made up of _____.
Elements are pure substances comprises atoms.
Explanation:An element is a substance that can't be separated into some other substance. Each element is comprised of its own kind of atom. This is the reason the chemical elements are for the most part mere different from one another.
The periodic table records all the discovered elements, gathering those with the same properties. The elements includes metals, non-metals, and metalloids. Most elements are metals, which conduct electricity and are shiny in nature. Metals incorporate iron, gold, and aluminum which are solid at room temperature.
Select all that apply.
Cyanobacteria _____.
serve as a food source for other organisms
are used for medicinal purposes
produce oxygen
perform nitrogen fixation
cause disease
Answer: all the answer applies
Explanation: Because of the composition rich in protein they are as food source for other organisms such as zooplankton, insects and snails.
they are used for medicinal purposes because have been identified as a rich source of biologically active compounds with antiviral, antibacterial, anti-fungal and anticancer activities, the compounds is polyhydroxyalkanoates.
the Cyanobacterias produce oxygen though the photosynthesis.
the Cyanobacterias cause disease because of theirs toxins
Answer:
Cyanobacteria performs all the function that given in the Question.
Explanation:
Cyanobacteria serve as a food for other organism, They are photosynthetic bacteria. Cyanobacteria and plants are capable of using light energy which trapped by the chlorophyll to convert carbon dioxide and water into oxygen and its food as a glucose, this process is called photosynthesis.
Cyanobacteria are used for medical purpose because they have rich source of biologically active compound with antibacterial, antifungal, antiviral activities.
Cyanobacteria produce oxygen because they oxygenic photosynthetic bacteria. They trap sun's energy absorbs carbon dioxide and emit oxygen.
Cyanobacteria performs nitrogen fixation because they contain additional fixed nitrogen which absorbs by the plants from their roots. Nitrification cannot occurs in the presence of oxygen. So, nitrogen is fixed iin the specialised cells called heterocysts.
What is the difference between a law about gravity and a theory about gravity?
Explanation:
This is a law because it describes the force but makes not attempt to explain how the force works. A theory is an explanation of a natural phenomenon. Einstein's General Theory of Relativity explains how gravity works by describing gravity as the effect of curvature of four dimensional spacetime.
Final answer:
A law about gravity describes the behavior of gravity with mathematical formula whereas a theory about gravity provides an explanation of why gravity behaves the way it does.
Explanation:The key difference between a law about gravity and a theory about gravity relates to their purposes and functions in the realm of science. A law, such as Newton's law of universal gravitation, describes the behavior of gravity. It provides a mathematical equation that predicts how gravity works in a variety of contexts. For instance, Newton's law of universal gravitation states that every particle of matter in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.
On the other hand, a theory provides an explanation of why gravity behaves the way that it does. Einstein’s theory of relativity, for example, offers an explanation of gravity as a curvature of space-time caused by mass and energy. The theory doesn't just describe what happens; it provides a framework for understanding why it happens.
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Mammals do not produce digestive enzyme B. However, sheep and cattle are two types of mammals that contain microorganisms in their digestive tract that produce enzyme B.
Which of the following best describes the process that adds a monosaccharide to an existing polysaccharide?
The monosaccharide is completely broken down by a specific enzyme and then the atoms are reorganized and made into a polysaccharide.
A
Ionic bonds are formed between adjacent carbon atoms of the monosaccharide and the polysaccharide by adding water (H2O) and a specific enzyme.
B
A specific enzyme removes the hydrogen (H) from the monosaccharide and the hydroxide (OH) from the polysaccharide, creating a bond between the two and creating a water (H2O) molecule.
C
A specific enzyme removes two hydroxides (OH) , one from the monosaccharide, and one from the polysaccharide, creating a bond between the two monosaccharides and creating a hydrogen peroxide ( H2O2 ) molecule.
D
Answer:
The correct option is this: A specific enzyme removes the hydrogen from the monosaccharide and the hydroxide from the polysaccharide, creating a bond between the two and creating a water molecule.
Explanation:
The process by which a monosaccharide molecule is added to an existing polysaccharide in biological systems is called CONDENSATION POLYMERIZATION.
During the process of condensation, an hydrogen atom and an hydroxide molecule from the reactants come together to form a water molecule; this leads to the formation of covalent bond between the reactants.
Condensation reaction is used in living organisms to produce complex macro molecules such as carbohydrates, proteins and lipids, which are needed by the body for health growth.
Remember, condensation reaction always results in loss of water molecules and formation of more complex molecule. One example of monosaccharide is glucose while cellulose (found in plants) and starch (found in animals) are examples of polysaccharides.
Answer:
B
Explanation:
This is called a dehydration reaction because water is released in the reaction for every glycosidic bond formed between two monomers. On one end of the polysaccharide, is an available 4’ carbon a --OH and an --H. This end of the polysaccharide will bond with the 1’ carbon of the monomer to form a glycosidic bond. The 1' carbon of the monomer will lose its --H while the 4’ carbon at the end of the polymer will lose an --OH. This releases a water molecule (--H + --OH --> H₂O) which is why the process is called a dehydration reaction.
How do enzymes act as catalyst in a chemical reaction ?
Enzymes, which are proteins found within cells, act as catalysts by lowering the activation energy required for a reaction to occur. They bind with specific molecules called substrates in a lock-and-key manner, facilitating their conversion into products. After the products are released, enzymes are free to interact with new substrates.
Explanation:Enzymes are proteins that drastically speed up the rate of virtually all of the chemical reactions that take place within cells. They act as catalysts by providing a different pathway for a reaction to proceed that has a lower activation energy. A key characteristic of enzymes is their specificity; they only bind to certain molecules, called substrates, which fit into the enzyme's active site in a lock-and-key manner.
During the enzyme-catalyzed reaction, the substrate is converted into one or more different molecules, known as products. When the products have been released, the enzyme is ready to bind with a new substrate and repeat the process, hence emphasizing the reusable nature of enzymes.
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2. How does the structure of an enzyme affect its function?
Explanation:
Enzymes. Most enzymes are proteins and therefore their function is specific to their structure. ... The enzyme binds with the appropriate substrate only in the correct alignment and orientation to connect the molecules. The resulting enzyme-substrate complex enables the reaction to occur.
what is the most important difference between Prokaryotic and Eukaryotic cells.
Prokaryotic cells lack a nucleus and organelles, while eukaryotic cells have both. This structural difference impacts complexity, specialization, and roles in biological systems.
The most significant distinction between prokaryotic and eukaryotic cells lies in their structural complexity and organization. Prokaryotic cells lack a defined nucleus and membrane-bound organelles, existing as simple, single-celled organisms. Eukaryotic cells, on the other hand, possess a well-defined nucleus enclosed by a nuclear membrane, alongside various membrane-bound organelles like mitochondria, endoplasmic reticulum, and Golgi apparatus.
This complexity enables eukaryotic cells to compartmentalize functions and facilitate specialized processes. Additionally, eukaryotes are typically larger and more intricate than prokaryotes. This differentiation in cellular structure underscores the fundamental diversity between these two cell types and reflects their distinct roles in various biological systems.
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Which of following is true of biochemistry