Answer: 12.5 x 10^6/10000 = 1250 cells.
Explanation:
A serial dilution is the step-by-step reduction of the concentration of a solution. Usually, the dilution factor at each step is constant, resulting in a geometric progression of the concentration, which is logarithmic. Serial dilutions are used to create very dilute solutions by accurately reducing the concentration of a substance.
It is usually carried out in experiments where highly dilute solutions are needed, for example, those involving logarithmic scale concentration curves or those used to determine the density of bacteria. To do this, prepare several test tubes with, for example, 9 ml of dilution liquid and first add 1ml of the undiluted sample to the first tube and then make serial dilutions in the following tubes. The first tube will contain a 1:10 dilution, the second 1:100, the third 1:1000, the fourth 1:10000 and so on.
Use 1 ml of undiluted (stock) solution with a pipette into the first test tube, containing 9 ml of a liquid, which can be for example water, Phosphate-buffered saline (PBS) and mix. This is the 1:10 solution. For the second dilution, take 1 ml of the dilution from the 1:10 tube and add it to the 9 ml of liquid to make the 1:100 tube and mix. The third tube is prepared with 1 ml of the 1:100 solution and 9 ml of liquid and this will be the 1:1000 dilution. The last one is prepared with 1 ml of 1:1000 and 9 ml of liquid and it will be 1:10000 (the fourth dilution).
So, if you start with 12.5 million cells and dilute four times with serial dilutions of 1:10 each, the final concentration will be four times lower:
12.5 x 10^6/10000 = 1250 cells.
1. Which of the following compounds in the main group is an alkaline earth metal?
O A. Sodium
O B. Calcium
C. Silicon
O D. Xenon
Answer:
B. Calcium
Explanation: short answer
Answer:
Calcium
Explanation:
Which of the following statements about survivorship curves is correct?
Answer:
A survivorship curve reflects the relationship of survival rate with age. best curves the statement about survivorship.
Explanation:
heyy mate! hope this helped you!
A survivorship curve is a graph that shows the proportion of individuals in a population surviving at different age intervals. The correct statement is that survivorship curve describes the pattern of mortality in a population over time. The correct option is C.
What is Survivorship curve?Survivorship curve describes the pattern of mortality in a population over time. The survivorship curve is divided into three types, i.e., Type 1, Type 2, and Type 3. Survivorship curve type 1 represents a high survival rate throughout the lifespan of the population. It shows that most individuals survive until old age, and the mortality rate increases at the end of the lifespan.
Survivorship curve type 2 shows a relatively constant rate of mortality throughout the lifespan of the population. It indicates that the probability of survival remains the same throughout life.
Survivorship curve type 3 represents high mortality rates among young individuals in a population. It shows that most individuals die young, and only a few individuals survive to adulthood.
Therefore, the correct option is C.
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Your question is incomplete, most probably the complete question is:
Which of the following statements regarding survivorship curves is correct?
a) survivorship curves are graphs that plot number of survivors (Nx) against age (x)
b) In type III curve, most individuals in the population die at the very early age
c) Survivorship curve describes the pattern of mortality in a population over time.
d) K-selected species typify populations that follow a type I curve
SYSTEMIC AORTA IS LOCATED AT?
Answer:
join now only............. it's running
Is it necessary to sustain Earth's resources?why?
Answer:
earth is the only planet we know of that sustain life please mark me brain list
In a Nitrogen metabolism study, the following data were obtained over the test period:
Nitrogen consumed 175 grams
Total Fecal N 35 grams
Metabolic Fecal N 10 grams
Total Urinary N 80 grams
Endogenous Urinary N 10 grams
Calculate:
a. Apparent Nitrogen digestibility (%)
b. True Nitrogen digestibility (%)
c. Nitrogen Balance (g)
d. Apparent Nitrogen Retention (%)
Answer:
a. 80%
b. 86%
c. 60 g
d. 34.29%
Explanation:
From the given information:
The apparent nitrogen digestibility (AD) is the ratio of the difference between the consumed nitrogen and fecal nitrogen to the consumed nitrogen.
Mathematically:
[tex]AD = \dfrac{consumed \ nitrogen - fecal \ nitrogen }{consumed \ nitrogen }[/tex]
[tex]AD = \dfrac{175 -35 }{175}[/tex]
AD = 0.8
To percentage, the apparent Nitrogen digestibility = 80%
b. True Nitrogen digestibility is calculated by the formula:
[tex]=\dfrac{consumed \ nitrogen - (fecal \ nitrogen -metabolic \ fecal)}{consumed \ nitrogen}[/tex]
[tex]= \dfrac{175 -(35-10)}{175}[/tex]
[tex]= \dfrac{175 -25}{175}[/tex]
= 0.86
= 86%
c. Nitrogen Balance = consumed Nitrogen - Fecal nitrogen - total uninary
Nitrogen Balance = (175 - 35 - 80) grams
Nitrogen Balance = 60 g
d. Apparent Nitrogen Retention (ANR) is computed as follows:
[tex]ANR = \dfrac{(consumed \ nitrogen-fecal\ nitrogen - total \ uninary )}{nitrogen \consumed }\times 100\%[/tex]
[tex]ANR = \dfrac{(175-35- 80 )}{175 }\times 100\%[/tex]
[tex]ANR = \dfrac{(60 )}{175 }\times 100\%[/tex]
ANR = 34.29%
Why is Glucose added to the fermenter with bacteria Becillus magaterium
Answer:
porque la glucosa genera mas desechos de alcohol y CO2.
Medio mínimo salino en que se reemplaza la glucosa por diferentes fuentes.
Medio de melaza de caña de azúcar 40 g/1 y urea 1,2 g/1 para fermentador.
producido por bacterias, como Bacillus subtilis en laboratorio bajo condiciones .
Explanation:
Which characteristic is unique to vertebrates?
A) they all have a well-defined skeleton
B) they have no defined organ systems
C) they have bilateral symmetry
D) they have an exoskeleton
Answer: They have well-defined skeleton.
Explanation:
This is because the vertebrates are uniquely characterised by the presence of the bones.
Answer:
Answer is A)They have a well-defined skeleton
Explanation:
most reasonable answer
information of vertebrates mammal
Answer:
A vertebrate is an animal with a spinal cord surrounded by cartilage or bone. The word comes from vertebrae, the bones that make up the spine. Animals that are not vertebrates are called invertebrates. Vertebrates are adapted to life underground, on the surface, and in the air. They feed upon plants, invertebrate animals, and one another. Vertebrate faunas are important to humans for food and recreation.Vertebrate Classes
Agnatha (Jawless Fish) Aves (Birds) Amphibia (Amphibians) Chondrichthyes (Rays, Sharks, Skates) Mammalia (Mammals) Osteichthyes (Bony Fish) Reptilia (Reptiles)
Explanation:
Which model best describes how gravity causes star formation?
Answer:
The choice b
Explanation:
took the test
Match the names of the microscope parts in column A with the descriptions in column B. Place the letter of your choice in the space provided.
Column A Column B
a. Adjustment knob (coarse) _______ 1. Increases or decreases the light intensity
b. Arm _______ 2. Platform that supports a microscope slide
c. Condenser _______ 3. Concentrates light onto the specimen
d. Eyepiece (ocular) _______ 4. Causes stage (or objective lens) to move upward or downward
e. Field of view _______ 5. After light passes through the specimen, it next enters this lens system
f. Iris diaphragm _______ 6. Holds a microscope slide in position
g. Nosepiece _______ 7. Contains a lens at the top of the body tube
h. Objective lens system _______ 8. Serves as a handle for carrying the microscope
i. Stage _______ 9. Part to which the objective lenses are attached
j. Stage (slide) clip _______ 10. Circular area seen through the eyepiece
Answer:
Adjustment knob (coarse) ---> Causes stage (or objective lens) to move upward or downward
Arm ---> Serves as a handle for carrying the microscope
Condenser ---> Concentrates light onto the specimen
Eyepiece (ocular) ---> Contains a lens at the top of the body tube
Field of view ---> Circular area seen through the eyepiece
Iris diaphragm ---> Increases or decreases the light intensity
Nosepiece ---> Part to which the objective lenses are attached
Objective lens system ---> After light passes through the specimen, it next enters this lens system
Explanation:
The microscope is an essential equipment used in science laboratories to view objects which are too small to be seen by the naked eye. Also certain processes which occur at the microscopic level can only be observed using a microscope.
There are many different types of microscopes. The compound light microscope is the one most commonly used in biological laboratories to view tissues and cells of organisms. It uses visible light which passes through two separate lens to magnify the image produced of a specimen.
The various parts of compound light microscope and their respective functions are given below:
Adjustment knob (coarse) ---> Causes stage (or objective lens) to move upward or downward
Arm ---> Serves as a handle for carrying the microscope
Condenser ---> Concentrates light onto the specimen
Eyepiece (ocular) ---> Contains a lens at the top of the body tube
Field of view ---> Circular area seen through the eyepiece
Iris diaphragm ---> Increases or decreases the light intensity
Nosepiece ---> Part to which the objective lenses are attached
Objective lens system ---> After light passes through the specimen, it next enters this lens system
Stage ---> Platform that supports a microscope slide
Stage (slide) clip ---> Holds a microscope slide in position
The correct match between microscope parts and names are:
A. adjustment knob (coarse) - 4.
B. Arm - 8.
C. Condenser - 3.
D. eyepiece (ocular) - 7.
E. Field of view - 10
F. Iris Diaphragm - 1
G. Nosepiece - 9
H. objective lens system - 5
I. Stage - 2
The microscope is an important piece of equipment used in biological science that helps in view objects that can not be seen by the naked eye. It is also used in various branches of science used to see certain processes that occur at the microscopic level.
A. adjustment knob (coarse) - Causes stage or objective lens to move up or down B. Arm - Serves as a handle for carrying the microscopeC. Condenser - focus or concentrates light onto the specimenD. eyepiece (ocular) - Contains a lens at the top of the body tubeE. Field of view - Circular area can be seen through the eyepieceF. Iris Diaphragm - helps to Increases or decreases the light intensityG. Nosepiece - Part to which the objective lenses are attachedH. objective lens system - After light passes through the specimen, it next enters this lens systemI. Stage - Platform that supports a microscope slideLearn more about microscopes:
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Is this right i’m confused?
If the last carbon atom of an unsaturated fatty acid is bonded to two hydrogen atoms and one carbon atom, what type of bond must exist between the last carbon and the other carbon atom?
single
double
triple
quadruple
Answer:
double
Explanation:
B
Double bond must exist between the last carbon and the other carbon atom.
What s unsaturated fatty acid?Unsaturated fats are commonly biosynthesized by a one of a kind dehydrogenation response called desaturation. The science of this change is wonderful in its selectivity.
The development and use of novel robotic tests (deutero-, fluoro-, thia-containing substrate analogs) has prompted a more refined comprehension of how unsaturated fat desaturases and related compounds complete their super particular oxidation science. The stereochemistry and request of hydrogen expulsion has been inspected for various solvent and layer bound desaturses.
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Explain how sunlight is the primary source of energy for your own life
Answer: ok...
Explanation:
The continual input of energy, mostly from sunlight, sustains the process of life. Sunlight allows plants, algae and cyanobacteria to use photosynthesis to convert carbon dioxide and water into organic compounds like carbohydrates. This process is the fundamental source of organic material in the biosphere.
Fill in the blanks
a. In general, ____________ moisture levels are associated with lower microbial diversity.
b. Bacteria in the small intestine thrive in _____________ pH than stomach bacteria.
c. The likelihood Of colonization by skin pathogens is ____________ when normal microbiota are present.
d. The occurrence of opportunistic infections ___________ in immunocompromised patients.
1. Higher
2. Lower
Answer:
a. lower
b.higher
c.lower
1.Higher
Explanation
Moisture is a great environment for bacteria to grow, the moister the environment is the more the bacteria will thrive, thinking about this lower moisture levels will result in lower microbial diversity.
The small intestine has higher ph than the stomach, this means that the bacteria there thrive in higher ph than the stomach bacteria.
Normal microbia in the skin usually acts as the first barrier against pathogens, while we have normal microbia it will protect us and will be less likely to get skin pathogens.
Immunocompromised patients are people that have received treatment to reduce their immunological system capacity, this means that even though this is done to battle a disease, another opportunistic infection can appear and take advantage of the fact that the defenses are low.
All of the following are correct about the typical American diet except that it is ?
A. High in sodium
B. Low in fiber
C. High in Calcium
Answer:
Explanation:
I believe the answer is the last one. The average intake in 2010 was 1030 mg approximately and that, according to experts is not enough.
The American diet is very high in sodium which is not good for your blood pressure. It was, some time ago, recommended that the average intake of Sodium should be about 2 grams. Two hamburgers will shoot that number to the moon, so now it is 4 grams. which if 2 grams was high, 4 grams is super high. Junk food prevails in America.
Fiber is true. It is low. The American Heart Association recommends 25 grams of Fiber a day. The average American takes in 15 which is only 60% of the recommended amount.
A farmer tested the soil in a field and found that there was a high nitrate salt concentration. The farmer then grew a crop in this field. After the crop was removed, the soil was tested again.
The nitrate salt concentration had decreased.
(a) Suggest reasons why the nitrate salt concentration had decreased
(b) Some species of plant grow well in soil that is always low in nitrate salt. Explain how
they can obtain a source of nitrogen compounds.
Answer:
The soil salt geted decereased because the plants in field absorbed salt from soil.Check all statements you agree with regarding the
purpose section of Proposal A.
This project will do a good job revealing the
effect of pesticides on honeybees.
It will help to establish a baseline for historical
comparison, a long-term benefit.
Society will benefit because the project will
indirectly increase the supply of honey and
other agricultural production.
The honey and agricultural industries will
benefit because bees will face fewer threats
Answer:
And will also reduce unemployment and also reduce morbidity
Phân tích chức năng của các hệ cơ quan chính ở cơ thể cá; các biểu hiện
rối loạn chức năng và ứng dụng các biện pháp kĩ thuật nhằm năng cao
năng suất nuôi trồng thủy sản
Answer:
Nâng cao kiến thức về hệ thống miễn dịch niêm mạc cá sẽ tạo điều kiện cho ... Tuy nhiên, có một số thách thức quan trọng để phát triển năng suất, ... Đầu tiên, kết quả thu được trong những năm đầu sẽ được phân tích, và điều này ... cơ quan và liên tục với các lớp lót của tất cả các lỗ trên cơ thể và cũng bao phủ các vây. và Cá cũng có thể sửa đổi cấu trúc mang để đáp ứng với độ mặn, thiếu oxy, hoặc axit hóa ... chưa rõ ảnh hưởng đến sức khỏe biển và sản lượng nuôi trồng thủy sản. ... để mở các hệ thống trong đó chất lượng nước là một chức năng trực tiếp của môi trường.
When talking about members of a
particular species, which of the
following makes the biggest
difference in the survival of an
organism in their environment?
A. external traits that we can see
B. internal traits that we cannot see
C. the eye color of the organism
D. the flower color of the organism
Answer:
either a or b
Explanation:
definitely not c or d.
II. NAMEM
Direction: Identify the word that best describes the following statement. Write your answer on
the space provided.
Ribonucleic Acid
1. These are molecules that code for hereditary traits by controlling the
production of protein.
2. These are carbohydrates that serves as a storing energy and are also
found in hormones and cell membrane components.
3. These are lipids which molecules are composed of fused rings of atoms
4. These are formed when two amino acids react with each other in an
acid-based reaction.
5. A nucleic acid that contains the genetic instructions used in the
development and functioning of all modern living organisms.
6. It transfers genetic code needed for the creation of proteins from the
nucleus to the ribosome or the protein synthesis.
7. It is the simplest sugar and the basic sub-unit of a carbohydrate.
8. This is the chief storage form of carbohydrates in plants and the most
important source of carbohydrates in human nutrition.
9. These are compounds with the same molecular formulas.
10. These are organic compounds formed by green plants from carbon
dioxide and water during the process of photosynthesis.
Starch
Peptide
Carbohydrates
Deoxyribonucleic acid
Isomers
Lipids
Monosaccharides
Nucleic Acid
Steroids
Ribonucleic Acid
Answer:
1. nucleic acids - these are the molecules also known as genetic material and code for the hereditary characteristics by regulating the production of the proteins.
2. Lipids - Lipids are the hydrocarbon and the major constituents of the cell membrane and molecules like hormones and give energy as well.
3. steroids - Steroids are lipids that have a fused ring structure and do not resembles other lipids however, have the same hydrophobic nature.
4. peptide - when two amino acids react with one another in an acid-base reaction there is a peptide bond form and the new molecule is called peptide and chains of such molecules known as polypeptides.
5. Deoxyribonucleic acid or DNA - It has genetic information code in it as specific sequences, it is used to develop and functions of various living organisms.
6. Ribonucleic acid or RNA - RNA is the molecule that play important role in protein synthesis as it (mRNA) carries the genetic code needed for the creation of proteins to the ribosomes from the nucleus.
7. Monosaccharides - Monosaccharides are the simplest form of Carbohydrates and known as a basic subunit of carbohydrates as these are linked to form complex carbohydrate molecules.
8. Starch - Starch is a carbohydrate found mainly in plants as the storage form of carbohydrates and provides nutrition to various organisms including humans.
9. Isomers - are the ompounds that have the same molecular formula but different chemical structures are called isomers.
10. Carbohydrates - it is the organic molecule and major source of nutrition that is produced by green plants from carbon dioxide and water through the process of photosynthesis.
Select the correct answer.
How much has the amount of carbon dioxide in the atmosphere increased since 1750?
А. 10%
B. 30%
C. 50%
D. 40%
Answer:
The answer is C. It has increased about 50% since 1750.
You are testing a new antibiotic in the microbiology lab. After treating Salmonella cells with the antibiotic, you wanted to see how many viable cells remain. Which of the following methods will provide the most accurate count of viable cells?
A. Fluorescence-activated cell sorting of unstained cells.B. Serial dilution followed by an optical density measurement.C. Counting cells directly using a hemocytometer.D. Serial dilution followed by a colony forming units calculation.
Answer:
D. Serial dilution followed by a colony forming units calculation.
Explanation:
The best way to count bacterial cells such as Salmonella accurately is through serial dilution and calculation of colony forming units.
Serial dilution is made using a petri dish containing appropriate culture medium for Salmonella growth. In this petri dish, with the help of an inoculation loop, the suspension containing the Salmonella will be scratched in the middle of the petri dish. Then, the inoculation loop will be passed over the salmonella streaks and will be dragged to the other side of the plate, where the loop will be scratched halfway through this space. The inoculation loop should again pass over the new salmonella streaks and be dragged through the rest of the petri dish. Then one must wait for the bacterial colonies to grow inside the plate.
Once these colonies are grown, those that appear in isolation will be counted through a specific calculation for the count of salmonella colonies.
Communication in the nervous system is called electrochemical. Why is this so?
Answer:
The movement of the action potential down the length of the axon is an electrical event, and movement of the neurotransmitter across the synaptic space represents the chemical portion of the process.
Prepare a collage of tools and equipment used in production of any one agricultural crop, from seed or planting through packaging of the produce
Answer:
i think
Explanation:
……………,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
Answer:
these r so many which one?
Explanation:
6. Which generations saw a population altering incident? Use your imagination to invent a
possible environmental incident that could have caused this shift in populations.
Answer:
Generations 1 and 6.
Some ideas for incidents might include a forest fire, lack of snowfall, flooding, earthquake, etc.
Explanation:
(:
The wavy vertical arrows represent water's introduction into which of Earth's systems?
a.atmosphere
b.biosphere
c.geosphere
d.hydrosphere
Answer:
B Biosphere is the system in which the arrows represent waters intro.
What is a mutation?
A. The visual appearance of an organism
B. A damaged protein
C. A permanent change in DNA or RNA
D. A harmful change to an organism's phenotype
Answer:d
Explanation:
it’s right
A chemical interferes with a cell's ability to make proteins. Investigations reveal that the cell parts responsible for making proteins are in working order. The cell can also
encode instructions for making proteins, but those instructions are not being carried out. The chemical appears to affect the communication between the
A Cell wall and Nucleus
B Nucleus and Ribosomes
C Mitochondria and Chloroplasts
D. Endoplasmic reticulum and Lysosomes
Answer:
I
Explanation:
What is a plant nucleus
Answer:
All plant cells contain a nucleus, a structure that stores DNA and acts as a cell's command center. It is surrounded by the nuclear envelope and is filled with nucleoplasm. ... DNA is copied during DNA replication for new cells, as well as copied to RNA to make proteins in the nucleus.