briefly outline how cell theory has developed over the past 400 years
Explanation:
The cell theory, or cell doctrine, states that all organisms are composed of similar units of organization, called cells. The concept was formally articulated in 1839 by Schleiden & Schwann and has remained as the foundation of modern biology. The idea predates other great paradigms of biology including Darwin’s theory of evolution (1859), Mendel’s laws of inheritance (1865), and the establishment of comparative biochemistry (1940).
First Cells Seen in Cork
While the invention of the telescope made the Cosmos accessible to human observation, the microsope opened up smaller worlds, showing what living forms were composed of. The cell was first discovered and named by Robert Hooke in 1665. He remarked that it looked strangely similar to cellula or small rooms which monks inhabited, thus deriving the name. However what Hooke actually saw was the dead cell walls of plant cells (cork) as it appeared under the microscope. Hooke’s description of these cells was published in Micrographia. The cell walls observed by Hooke gave no indication of the nucleus and other organelles found in most living cells. The first man to witness a live cell under a microscope was Anton van Leeuwenhoek, who in 1674 described the algae Spirogyra. Van Leeuwenhoek probably also saw bacteria
The cell theory, states that all organisms are composed of similar units of organization, called cells.
What is cell theory?The concept of cell theory was in 1839 by Schleiden & Schwann which leads the foundation of modern biology. Cell theory states that every cell is generated from another preexisting cell.
This idea makes the great revolution in biology including Darwin’s theory of evolution (1859), Mendel’s laws of inheritance (1865), and the establishment of comparative biochemistry (1940).
Schleiden & Schwann propose every organism is composed of the cell, which is the basic unit of life and each cell comes from the preexisting cell, and each cell produces a progeny which is similar to its parent cell.
Therefore, cell theory states the existence of the cell in the organism.
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Resources have an ethical value if A. They are used to produce goods. B. We have a right to take advantage of them. C. They are particularly beautiful. D. We have a duty to protect them.
Answer:
D.Explanation:
Ethical values mean that a resource is important to conserve, protect, and use responsibly.
I'm always happy to help :)The diagram shows a straight chain of glucose molecules.
Which carbohydrate is shown above?
O fructose
O sucrose
O galactose
Ostarch
Answer:
Starch
Explanation:
Starch is a polysaccharide composed of many glucose molecules linearly arranged.
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Fructose, sucrose, galactose, and glucose are carbohydrates. They are organic compounds with H, C, and O. Their functional groups are hydroxyl (-OH) and carbonyl (-C=O).Galactose, fructose, and glucose are isomeric monosaccharides, with the formula C₆H₁₂O₆.
Sucrose is a disaccharide composed of glucose + fructose. The formula is C₁₂H₂₂O₁₁.
Glucose is the most abundant carbohydrate. The main source of glucose is vegetable starch.
The starch molecule is composed of many glucose molecules joined.This is a linear polysaccharide that can acquire a tridimensional helicoidal conformation. Each of the helices turns consists of six glucose molecules. In the interior of the helix, there are only hydrogen atoms. Hydroxyl groups are facing the exterior.
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The digestive and excretory systems
THE EXCRETORY SYSTEM
Answer: The attachment shows the nephron which is the functional unit of the kidney.
It does the work of urine formation through 3 distinct processes.
-Ultra filtration( Small molecules are forced out of the selectively permeable membrane of the glomerulus into the Bowman's capsule under regulated pressure.these molecules are from the blood in the glomerulus brought in by the afferent arteriole.
- Selective reabsorption ( Useful molecule and iron such as glucose and sodium are reabsorbed back into the blood as the filtrate flows through the tubule(nephron)
-Tubular Secretion. ( Movement of molecules not filtered by the glomerulus during the initial stage of filtration back into the filtrate through the renal capillaries.
Stella's urine sample shows the presence of large protein (ULTRAFILTRATION)
John's blood test report indicates a high toxin level ( ULTRAFILTRATION AND TUBULAR SECRETION)
Miguel's blood test shows an increase in metabolic waste( ULTRAFILTRATION AND TUBULAR SECRETION)
Janice's urine report shows the presence of vital materials ( SELECTIVE REABSORPTION).
Antibodies:_______. A. play a large role in cell-mediated immunity. B. are produced by both T and B cells. C. are composed of four light and four heavy polypeptide chains. D. are not specific, but act generally. E. have a variable region that binds to a specific antigenic determinant.
Answer:
E. have a variable region that binds to a specific antigenic determinant.
Antibodies E. have a variable region that binds to a specific antigenic determinant.
What is the region of the antibody that the antigen binds to?This location of the antibody is known as the Fab (fragment, antigen binding) place. it's far composed of 1 constant and one variable domain from every heavy and light chain of the antibody. The paratope is shaped on the amino terminal cease of the antibody monomer by the variable domains from the heavy and light chains.
What binds to an antigenic determinant?An antigenic determinant is a website online of an antigen molecule that is termed an epitope and interacts with the unique antigen-binding site within the variable vicinity of an antibody molecule called a paratope.
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Technology has affected society by causing radical changes in how people live. For example, e-mail on the computer has changed the way we communicate with the world. Describe another example of how technology has changed how people live
Answer: the modern production of the cars change the way of transportation
Modern houses change the way where people locate
Another example of how technology has changed how people live is the widespread use of smartphones and mobile applications.
Smartphones have become an integral part of daily life for many people, revolutionizing the way we communicate, access information, and carry out various tasks.
Some ways in which smartphones and mobile applications have transformed our lives:
1. Communication: Smartphones have made communication more convenient and accessible. With features like instant messaging, video calls, and social media apps, people can easily connect with others regardless of their location.
2. Information Access: Smartphones provide instant access to a vast amount of information through the internet. With a few taps on a smartphone screen, people can search for news, look up facts, find directions, or access educational resources.
3. Online Shopping: E-commerce platforms and mobile shopping apps have revolutionized the way people shop. With smartphones, individuals can browse and purchase products or services from anywhere, anytime.
These are just a few examples of how smartphones and mobile applications have significantly changed the way we live.
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Natural selection states that complex organisms evolved through random mutations alone. True or False?
Answer:
False.
Explanation:
This statement is false because organisms don't evolve - populations do. New gene variants (i.e., alleles) are produced by random mutation, and over the course of many generations, natural selection may favor advantageous variants, causing them to become more common in the population. However, because mutation rates are low relative to population growth in most species, mutation alone doesn't have much of an effect on evolution.
Which of the following statements is true?
Photosynthesis is a type of homeostasis.
Unicellular organisms have differentiated cells.
Respiration is a type of metabolism.
Multicellular organisms are made of only one cell.
Answer:
Respiration is a type of metabolism.
Answer:
C. Respiration is a type of metabolism
Explanation:
Both B and D are incorrect because:
Multicelluar organisms have more than one cell; while singlecelled organisims only have one cell.
Also, homeostasis is a natural way an organisms body reacts to different situations, like when you sweat, your body is realising a way to lower the heat in your body. Therfore, A. is also incorrect.
Hope this helped!
what are the challenges faced by the role of climate on crop production?
Answer:
Climate on crop production contribute to the greenhouse effect and climate change and impacts on agriculture production.
Explanation:
Crop production of climate change is likely to change food security in the future, all people and economic to sufficient and safe an active life.
Climate change is to contribute to food prices and food production, and expensive climate change increase energy prices,production may increased crop water and suitable production.
Agriculture and food product system is a major process source of gas,could increase products,yield of crop restricted by the extreme events.
Productivity can also effects on the immune system them certain diseases,in animals are productivity and fertility.
Crop level to climate change is expected be in future changing crop irrigation practices,crop production under global change.
Climate change extreme events have been and strategies suggest to help maintain production and restoring farm type, crop, food systems, crop that stress tolerance.
Based on fossilized evidence, there are scientific claims made about the evolution of certain species. If a scientist studying the fossils of a specific species had a hypothesis other than what was currently accepted, what steps should be taken to have the alternative hypothesis considered
Answer: For the scientist to have alternative hypothesis considered, it is imperative he takes certain steps, this steps will ascertain the scientific claims already made about the evolution of species.
Therefore,the scientist will simply test the alternative hypotheses inorder to know that they are incorrect.
This testing of hypotheses to ascertain their incorrectness is very useful in the study of fossils.
Which describes a grizzly bear’s habitat? all the biotic factors in the ecosystem all the abiotic factors in the ecosystem the role of the bear in the ecosystem the physical area where the bear lives
Answer:
it is D
Explanation:
A grizzly bear’s habitat comprises of the physical area where the bear lives
What is a habitat?A habitat is defined as the dwelling home of living organisms.
There are three major types of habitat; namely:
Terrestrial habitatAquatic habitatArboreal habitatTerrestrial habitat is the land habitatAquatic habitat is the water habitatArboreal habitat is the tree habitatLearn more about habitat:
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What happens when volcanoes release greenhouse gases into the atmosphere?
Answer:
a. the climate gets warmer...
Explanation:
When volcanoes release greenhouse gases into the atmosphere, global warming is due to the greenhouse effect.
What do you mean by the Greenhouse effect?The Greenhouse effect may be defined as the phenomenon of keeping the earth warm due to the presence of certain gases in the atmosphere.
Greenhouse gases like carbon dioxide, Methane, and Nitrous oxide allow the solar radiations to enter but prevent the escape of heat radiations of longer wavelength.
Due to this, the gradual and continuous increase in the average temperature of the earth's surface occurs, a phenomenon known as global warming.
Therefore, when volcanoes release greenhouse gases into the atmosphere, global warming is due to the greenhouse effect.
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Abnormal vascular regulation by endothelial cells in small vessels of the heart contributes to:___________. a. Hypertension b. Dysrhythmias c. Truncus arteriosus d. Ischemic heart disease
Answer: The correct answer to the question is option D
ISCHEMIC HEART DISEASE.
Explanation: To answer the question effectively, let us look at the options given,what they are and how they affect the heart.
Endothelial cells play a crucial role in the regulating vascular tone,They do so by secreting variable amounts of constricting and relaxing factors inorder to control tissue perfusion.
Hypertension on the other hand occurs as a result of factors that varies distinctively and not all related to vascular tone.
Dysrhythmias on it's own will affect the function and conduction of heart chambers but not necessarily vascular tones.
Truncus arteriosus results in only in one large artery exiting/leaving the heart.
30 POINTS PLZ HELP I WILL GIVE BRAINLIEST Identify and describe the two main methods for measuring the age of Earth and its parts.
Answer:
Radiation Measurement.
Stratigraphic Superposition.
The Fossil Record.
Explanation:
Answer:
Radiation Measurement.
Stratigraphic Superposition.
The Fossil Record.
Explanation:
Which process that causes changes in Earth's orbit was found to coincide with 100,000-year glacial cycles? Answer Options: A. Axial precession B. Precession of the ecliptic C. Apsidal precession D. Obliquity
Answer:
Apsidal precession
Explanation:
Apsidal precession is the process that causes changes in Earth's orbit and was found to coincide with 100,000-year glacial cycles. Thus, the correct option is C.
What is the Glacial cycle?The glacial cycle may be defined as a significant global climatic oscillation of the order with a specific rate that is developed by the ice age.
Apsidal precession is the precession of the line that links the apsides of an astronomical body. The regular cycle of apsidal precession takes about 100,000-year.
Therefore, the correct option for this question is C.
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If capeland switches from producing 0 watermelons to producing 18 million tons of watermelons, what does it give up?
Answer:
Attached to this solution is an image of the complete question and data.
The correct answer is:
6 million pairs of shoes
Explanation:
From the diagram attached to this answer, the following data can be gotten:
Watermelons shoes
(Millions of tonnes) (Millions of pairs)
0 15
8 14
14 12
18 9
20 5
21 0
From the pattern of the data shown above, we notice that as the production of one commodity increases, the other is given up (decreases)
Therefore, to find how much shoes are given up if Capeland switches from 0 watermelons to 18 million tons of watermelon, we will find the difference between the number of shoes produced at 0 and at 18 million tons of watermelon
at 0 watermelon; shoes = 15 million pairs
at 18 million tons of watermelon; shoes = 9 million pairs
Therefore, number of shoes given up = 15 - 9 = 6 million pairs
Hence, 6 million pairs of shoes are given up tp increase production of watermelon from 0 to 18 million tons
about plant kingdom
2) Micah and Taylor investigate the effect of tap water and spring water on the growth of plants.
They grew two plants of the same type and size in separate containers. Every three days, they
added the same amount of tap water to one plant and the same amount of spring water to the
other. Describe an action that would best improve the reliability of their results?
Answer:
To improve the reliability of the results, the nutritional component of each category of water must be tested and recorded.
Second, the experiment should be carried out under greenhouse conditions.
The above actions will afford more control. When an experiment is controlled, it means that except for the dependent variable, all other variables are kept constant by the scientist.
By performing the experiment under greenhouse conditions, the kind of water the plants receive, temperature and other biotic actors are kept within measurable limits thus increasing the reliability of the results.
Cheers!
Imagine you discover a new human parasite like T. gondii that forms cysts in the brain. You suspect it is altering human behavior. You also determine that it is transmitted through sharing food. In what ways would you predict that it zombifies its hosts (alters their behavior)?
Hello. This question is incomplete. The full question is:
Imagine you discover a new human parasite like T. gondii that forms cysts in the brain. You suspect it is altering human behavior. You also determine that it is transmitted through sharing food. In what ways would you predict that it zombifies its hosts (alters their behavior)?
a. It should make them feel sick and rest in bed.
b. It should make them want to host more people for social dinners.
c. It should make them want to prepare meals more.
d. It should reduce their sanitary practices (e.g. washing hands) while preparing food.
e. It should make them want to horde food.
Answer:
a. It should make them feel sick and rest in bed.
b. It should make them want to host more people for social dinners.
c. It should make them want to prepare meals more.
d. It should reduce their sanitary practices (e.g. washing hands) while preparing food.
Explanation:
The options shown above are the only ones that show possible changes in personal behaviors related exclusively to the behavior of a person, who may be suffering from the damage caused by a parasite in the brain. The "e" option does not represent a change in behavior and does not depend exclusively on a sick individual due to the action of a parasite.
As you may already know, the brain governs our body in all factors, for this reason, cysts in this organ can trigger behavioral changes.
Answer: a. It should make them feel sick and rest in bed.
Explanation:
The full question is:
Imagine you discover a new human parasite like T. gondii that forms cysts in the brain. You suspect it is altering human behavior. You also determine that it is transmitted through sharing food. In what ways would you predict that it zombifies its hosts (alters their behavior)?
a. It should make them feel sick and rest in bed.
b. It should make them want to host more people for social dinners.
c. It should make them want to prepare meals more.
d. It should reduce their sanitary practices (e.g. washing hands) while preparing food.
e. It should make them want to horde food.
Toxoplasma gondii is a protozoan parasite that causes toxoplasmosis, a generally mild but potentially fatal disease, especially in cats and human fetuses. Cats and other felines are considered their ultimate hosts because the sexed phase of their life cycle takes place there, making these animals the primary hosts of the parasite. The asexual phase of the life cycle can occur in any warm-blooded animal, such as other mammals and birds. Therefore, toxoplasmosis is a parasitic zoonosis.
Parasites invade the cells, forming a compartment called the parasitophore vacuole which form cysts in tissues, especially in the muscles and brain. Because the parasite is inside the cells, the host immune system does not detect these cysts. Antibiotic resistance varies, but cysts are difficult to eradicate entirely. Therefore, T. gondii spreads within these vacuoles through a series of binary divisions until the infested cell eventually breaks free.
Some people have flu-like signs and symptoms, which may be:
Swollen lymph nodesHeadacheFeverFatigueWidespread painIn people with impaired immune systems, symptoms may also include:
ConfusionLack of coordinationConvulsionsBlurred vision caused by intense swelling of the retinaIn recent years, several investigations indicate that the parasite can cause changes in the behavior associated with impulsivity, and personality disorders. So, we could predict it zombifies the host by changes in the behavior, because of the damage caused by a parasite in the brain. It is important to consider that the brain governs the body, and cysts found there can trigger these changes.
Jameson lives in a city on the shores of the Atlantic Ocean. The temperature fluctuations are relatively small in his city because takes longer to heat up and cool down due to its high .
Answer:
Water, high specific heat capacity
Explanation:
The temperature fluctuations are relatively small in Jameson city because takes water longer to heat up and cool down due to its high specific heat capacity because water has high heat capacity that is it absorb alot of heat before it start to get hot. takes more energy to increase the temperature of water compared to other substances which help to regulate extremes in the environment.
Water surrounding cities take longer to heat up and longer to cool down so cities that are near the oceans will tend to have less change and less extreme temperatures compared to inland cities.
Answer:
I believe it's (water and specific heat) let me know if this is correct :)
A country's ecological footprint can be calculated by multiplying its population size by the footprint of each individual. Why are some ecologists concerned about the ecological footprint of a country like India
Answer:
Ecological footprint estimates the requirements of renewable resources that a population consumes to live a particular lifestyle. Some ecologists are concerned because the result of the ecological footprint shows that the demand of the population is increasing in comparison to the supply of nature.
For example in India, the ecological footprint shows negative impact of population demand over supply of nature.
The incidence of phenylketonuria (PKU), an autosomal recessive genetic disorder, is approximately 1 in 4,500 in Ireland. Assuming Hardy-Weinberg equilibrium, what is the probability that an Irish female, who is phenotypically normal with no family history of PKU, and an Irish male, who like his parents does not have PKU, but does have a sister with PKU, will have a child with PKU?
Answer: Probability: 0%
Explanation:
Hardy-Weinberg establishes that the genetic composition of a population remains in equilibrium as long as no natural selection or other factors act and no mutations occur. This means that the children of this couple will inherit the genes of the parents.
The woman is phenotypically normal with no family history of PKU, this mean that probably there are no affected (recessive) alleles in her family. In an autosomal recessive disorder, both copies of the gene in each cell are recessive. Therefore, her genotype will be AA with A being the dominant and normal allele. As for the Irish man, his sister does have PKU, which means her genotype is aa. So, she must have received a defective allele from each parent. Then the parents' genotypes are both Aa (heterozygous, only one allele affected as they are healthy). So, we know that the Irish man does not have the disease (he can't be aa), but he could be Aa (having inherited a normal allele from one parent, and an affected one from the other parent) or AA (having inherited both normal alleles from each parent).
Then we have two possible punnetts square to do: AA (the Irish woman) and AA (he Irish man); or AA (woman) and Aa (man).
In the attached figure both punnetts squares are shown. The first punnett square (AA x AA) shows that 100% of the offspring will be AA (this means, the phenotypic ratio is also 100% not affected and non-carrier). The second punnett square (AA x Aa) shows that 50% will be AA (healthy and non-carrier) and 50% will be Aa (heterozygous, healthy and carrier) But since it is an autosomal recessive disease, a single affected allele is not enough to develop the disease. So in neither case is there a chance of having a child with PKU.
Match the causes with their effects.
Answer:
"destroys->deforestation"
"Oil spills->harms aquatic"
"injecting->pollutes"
1. deforestation
2. injecting fracking fluids into the ground
3. oil spills during transport on a ship
Consider the following chromosomes and if they are affected by hemophilia.
X = unaffected X chromosome, x = X chromosome affected by hemophilia, and Y = Y chromosome.
If an Xx female and XY male have children, what fraction of their offspring will have an affected chromosome, and what fraction is likely to be affected by hemophilia?
(1 point)
A. 1/4 and 1/2
B. 1/2 and 1/4
C. 1/2 and 1/3
D. 1/4 and 1/4
I've been stuck on this question for a while, may someone please assist?
Answer:
B. 1/2 and 1/4
Explanation:
Hemophilia is a rare disease that has to do with the inability for blood to clot. It is inherited on the X chromosome, hence, it is said to be X-linked. It is usually passed from mother to son. According to this question;
X - unaffected X chromosome
x = X chromosome affected by hemophilia
Y = Y chromosome
Therefore, in a cross between a Xx female (carrier) and a XY male (unaffected), the following chromosomes will be present in the gametes produced by each parent:
Xx- X and x gametes
XY- X and Y gametes
Using these gametes in a punnet square (see attached image), offsprings with genotypes: XX, Xx, XY and xY will be possibly produced.
XX (1) - unaffected female
Xx (1) - unaffected but carrier female
XY (1) - unaffected male
xY (1) - affected male (have hemophilia)
Based on the questions;
- 2 out of the possible 4 children will have the affected chromosomes i.e. both xY son and Xx daughter have the affected (x) chromosome. Hence, the fraction is 1/2
- 1 out of the 4 possible children is affected by hemophilia, which is the xY son. Hence, the fraction is 1/4.
what is the hypothesis
Answer:
a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation.
Explanation:
Answer:
what you think is gonna happen in an experiment
Explanation:
why is it necessary yo separate oxgynated and deoxgynated blood in livng oranisum
Explanation:
it is necessary in mammals and birds to separate oxygenated and deoxygenated blood because this makes their circulatory system more efficient and helps in maintaining a constant body temperature
CER
Can someone help me with these questions? Thank you.
Answer:
1.C
2.E
3.C
4.R
5.E
6.R
7.E
8.C
9.E
(do not take my word for it maybe wait for someone else to answer to compare to mine)
Which is most likely a source of air pollution?
Answer:
CFC's
Explanation:
What is the definition of salinity ?
Answer:
Salinity pertains to the degree of saltiness or the relative proportion of salt in a solution. ... By definition, salinity in relation to limnology refers to the total amount of dissolved solids in water in parts per thousand by weight.
Answer:
Salinity is the saltiness or dissolved inorganic salt content of a body of water. Substances that are dissolved in water are usually called solutes.
Explanation:
Eye color is an example of 1. Transcriptional control 2. gene expression 3. translational control 4. gene regulation
Eye color is an example of Gene expression
