measuring absorbance numbers using a spectrophotometer can allow one to determine if cells are
Answers
Measuring absorbance numbers using a spectrophotometer can allow one to determine if cells are present or their concentration in a sample.
When light passes through a sample, molecules in the sample can absorb specific wavelengths of light. This absorption is measured as absorbance, which indicates the amount of light absorbed by the sample. Cells can contribute to the absorbance of a sample due to their light-absorbing properties. By measuring the absorbance of a sample at a specific wavelength, one can determine if cells are present in the sample. This is because more cells lead to increased light absorption. Spectrophotometers can be used in various applications, such as cell culture analysis, microbiology, and biomedical research, where quantifying cell concentration or detecting the presence of cells is crucial.
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Related Questions
6. Name two ways that bacteria become resistant to antibiotics?
Why is it important to practice a technique before using it in the lab?
Answers
1. Bacteria can acquire resistance through mutations in their DNA that allows them to survive in the presence of antibiotics.
1. Bacteria can acquire resistance through mutations in their DNA that allows them to survive in the presence of antibiotics.2. Bacteria can also acquire resistance through horizontal gene transfer, where they obtain resistance genes from other bacteria.
It is important to practice a technique before using it in the lab to ensure that you understand the process and become familiar with any potential hazards that may arise. Practicing techniques also allows you to troubleshoot any issues that may occur, and save time when performing the experiment.
1) Eight (8) things need to be documented on the autoclave log.
List them.
2) Why do you need to use sterile towels to remove the
instrument pan from the autoclave at the end of the cycle? (hint:
the
Answers
On an autoclave log, eight things need to be documented: date and time, operator's name, cycle type, load contents, cycle parameters, cycle results, maintenance and calibration activities, and the signature of the person documenting. Sterile towels are used to remove the instrument pan from the autoclave to protect the operator from burns and provide a clean surface, in addition to maintaining instrument sterility.
1) Eight things that need to be documented on the autoclave log are:
Date and time: The exact date and time when the autoclave cycle begins and ends should be recorded for tracking purposes.Operator's name: The name or initials of the person responsible for running the autoclave should be documented for accountability.Cycle type: The type of autoclave cycle used, such as sterilization or decontamination, should be specified for proper identification.Load contents: A detailed description of the items or materials being sterilized, including any special considerations or instructions, should be recorded.Cycle parameters: The specific parameters of the autoclave cycle, such as temperature, pressure, and duration, need to be documented to ensure proper sterilization.Cycle results: The outcome of the autoclave cycle, such as pass/fail or any deviations from expected results, should be noted for quality control purposes.Maintenance and calibration: Any maintenance activities, repairs, or calibration performed on the autoclave should be logged to ensure its proper functioning.Signature: The signature or initials of the person documenting the autoclave log should be included to verify the accuracy of the recorded information.2) Sterile towels are used to remove the instrument pan from the autoclave at the end of the cycle for reasons beyond simply keeping the instruments sterile.
The primary purpose of using sterile towels is to protect the operator from burns or injuries caused by direct contact with hot surfaces. Autoclaves operate at high temperatures and the instrument pan can be extremely hot after the sterilization cycle.
By using sterile towels as insulation, they provide a barrier between the hot instrument pan and the operator's hands, minimizing the risk of burns or other injuries.
Additionally, sterile towels can also provide a clean and hygienic surface to handle the instruments, preventing contamination from any external sources and maintaining the sterility of the instruments until they are ready for use.
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mr. and mrs. smith’s child was diagnosed with turner syndrome. their child has a(n) _________ chromosome
Answers
Turners syndrome is a genetic disorder caused due to the deletion of partial or complete of a X chromosome.
Turners syndrome affects only females. There are 44 autosomal chromosomes and a pair of sex chromosomes in humans. In males there are a X and Y chromosomes. In females there are two X chromosomes.
In turners syndrome, one of the X chromosome is deleted either partially or completely. In infant stage it causes Wide or weblike neck, Low-set ears, Broad chest with widely spaced nipples etc.
During puberty and adult stages, the symptoms become more prominent like No growth spurts at expected times in childhood, Failure to begin sexual changes expected during puberty, Sexual development stops during teenage years, Early end to menstrual cycles, For most females with Turner syndrome, inability to conceive a child without fertility treatment.
So turners syndrome is diagnosed with child has an X chromosome.
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in response to falling blood glucose levels, which pancreatic islet cell releases glucagon?
Answers
A hormone called glucagon is important in regulating blood sugar (glucose) levels. It is synthesized by alpha cells and then released into the bloodstream from the pancreatic islets of Langerhans.
When blood glucose levels are too low, the pancreas releases more glucagon into the body (low blood glucose). In numerous ways, this hormone aids in the recovery of blood glucose: As a result, the liver releases glucose into the bloodstream after converting stored glucose into a usable form. Alpha cells in the islets of Langerhans secrete glucagon, and beta cells secrete insulin. The hormones insulin and glucagon control the body's glucose level to maintain it within a healthy range.
We can therefore conclude that glucagon, a hormone, is crucial for controlling blood sugar (glucose) levels. The pancreatic islets of Langerhans' alpha cells are responsible for their production.
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Aupporting cells of the nervous system are collectively called:
Answers
Supporting cells of the nervous system are collectively called neuroglia.
Answer:
They are called neuroglia or glial cells.
how photosynthesis and cellular respiration work together
Answers
Answer:
Photosynthesis converts carbon dioxide and water into oxygen and glucose. ... Cellular respiration converts oxygen and glucose into water and carbon dioxide. Water and carbon dioxide are by- products and ATP is energy that is transformed from the process.
Hope this helped :)
Explanation:
it is multiple choice
Answers
Answer:
Id say its B or D but dont take my word for it
Explanation:
Answer:
A
Explanation:
I had a 99 in geoscience
How does the human immune system destroy a pathogen in the body?A. B cells release antibodies that neutralize the pathogen.B. Antibiotics are released by B cells to destroy the pathogen.C. Lymphocytes recognizes pathogens as antigens in the body.D. T cells build immunity to the pathogen by releasing antibodies.
Answers
T cells are important to our immune system, but they do not release antibodies. They activate B cells and cytotoxic T lymphocytes to kill cells that are infected. Therefore, D is incorrect.
Antibiotics are not produced by our immune system. They can be found in nature or synthesized in labs. Therefore, B is incorrect too.
Lymphocytes are divided into T and B cells. B lymphocytes release antibodies that will recognize pathogens and bind to them, but T cells doesn't work like that. Lymphocyts does not recognize pathogens and C is incorrect as well.
B cells create antibodies, release them and they will bind to pathogens to neutralize them. Therefore, the correct answer is A. B cells release antibodies that neutralize the pathogen.
What are the flattened membranes in chloroplasts called?
O A. Stroma
OB. Thylakoids
C. Photosystems
D. Photons
Answers
Answer:
Thylakoids
Explanation:
OB. thylakoids
QUESTION 1 Exercise 11.10. Butterflies. Alice, Bob, and Charlotte are looking for butterflies. They look in three separate parts of a field, so that their probabilities of success do not affect each other. • Alice finds 1 butterfly with probability 17%, and otherwise does not find one • Bob finds 1 butterfly with probability 25%, and otherwise does not find one • Charlotte finds 1 butterfly with probability 45%, and otherwise does not find one Let X be the number of butterflies that they find altogether. Write X as the sum of three indicator random variables, X1, X2, X3 that indicate whether Alice, Bob, Charlotte (respectively) found a butterfly. Then X= X1+X2 +X3. Find the expected value of X by finding the expected value of the sum of the indicator random variables. Your answer will have two decimal places. **This is a straight forward expected value of a sum of random variables, nothing fancy here! QUESTION 2 Exercise 11.16. Flipping coins. Flip a coin until the second head comes up. Let X be the number of flips needed to get the second head. What is the E(X). The first step is to find the expected value of getting the first head. Is this like Example 11.10, sampling without replacement, OR like Example 11.11, sampling with replacement? O A. Example 11.10, sampling without replacement O B. Example 11.11, sampling with replacement QUESTION 3 Exercise 11.16. Flipping coins. Flip a coin until the second head comes up. Let X be the number of flips needed to get the second head. What is the E(X). The first step is to find the expected value of getting the first head. What is the expected value of getting the first head? This will be an integer answer. QUESTION 4 Exercise 11.16. Flipping coins. Flip a coin until the second head comes up. Let X be the number of flips needed to get the second head. What is the E(X). The next step is to find the expected value of getting the second head. Because this is identical to finding the expected number of rolls for the first head (independent events), we just multiply the first head's expected value by 2. This will be an integer answer. QUESTION 5 Exercise 11.17 (a). Waiting for favorite song. Michael puts his iTunes on shuffle mode where songs are not allowed to be replayed. He has 2,781 songs saved on iTunes, and exactly one of these is his favorite. How many songs is he expected to have to listen to until his very favorite song comes up? Is this like Example 11.10, sampling without replacement, OR like Example 11.11, sampling with replacement? A. Example 11.11, sampling with replacement B. Example 11.10, sampling without replacement
Answers
In Exercise 11.10, the expected value of the number of butterflies found by Alice, Bob, and Charlotte is obtained by finding the expected value of the sum of three indicator random variables.
In Exercise 11.16, the expected value of the number of flips needed to get the second head in a coin flipping experiment is determined. These exercises involve different scenarios of sampling with and without replacement.
In Exercise 11.10, the expected value of X, the total number of butterflies found, is found by calculating the expected value of each indicator random variable (X1, X2, X3) representing whether Alice, Bob, and Charlotte found a butterfly, respectively.
The expected value of each indicator variable can be obtained by multiplying the probability of success (finding a butterfly) by 1 and the probability of failure (not finding a butterfly) by 0. Then, the expected value of X is calculated as the sum of the expected values of the indicator variables.
In Exercise 11.16, the expected value of X, the number of flips needed to get the second head, is determined. To find this value, we first need to find the expected value of getting the first head. This scenario is similar to Example 11.11, which involves sampling with replacement.
Each coin flip is an independent event, and the probability of getting a head is constant at 0.5.
Therefore, the expected value of getting the first head is 1/p, where p is the probability of success (0.5 in this case).
In Exercise 11.17 (a), the scenario of waiting for a favorite song in Michael's iTunes playlist involves sampling without replacement. Each song played is not replayed, and there is only one favorite song among the total number of songs.
Therefore, this scenario is similar to Example 11.10, sampling without replacement.
To find the expected number of songs Michael needs to listen to until his favorite song comes up, the formula for sampling without replacement is used, which is the reciprocal of the probability of selecting the favorite song at each step.
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use the following reef organisms to develop 3 different trophic pyramids, listed from base to top: reef shark, algae, gastropod, herbivorous fish, bivalve, crab, sea urchin
Answers
One possible trophic pyramid using the listed reef organisms is:
1. Algae (primary producers)
2. Herbivorous fish (primary consumers)
3. Reef shark (secondary consumers)
Another possible trophic pyramid is:
1. Bivalve (primary producers)
2. Gastropod (primary consumers)
3. Crab (secondary consumers)
A third possible trophic pyramid is:
1. Sea urchin (primary producers)
2. Herbivorous fish (primary consumers)
3. Reef shark (secondary consumers)
In each of these trophic pyramids, the organisms at the base are the primary producers, followed by primary consumers and then secondary consumers. The specific organisms used in each pyramid may vary, but the overall structure remains the same. This highlights the interconnectedness of the reef ecosystem and the importance of each organism in the food chain.
Here they are:
Trophic Pyramid 1:
1. Base: Algae
2. Herbivorous Fish
3. Crab
4. Reef Shark
Trophic Pyramid 2:
1. Base: Algae
2. Gastropod
3. Bivalve
4. Reef Shark
Trophic Pyramid 3:
1. Base: Algae
2. Sea Urchin
3. Herbivorous Fish
4. Reef Shark
These trophic pyramids represent different food chains within a coral reef ecosystem, with algae as the primary producer and reef shark as the apex predator.
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What is the difference between a theory and a
law?
A. A law is a uniform constant of nature,
whereas a theory can still be questioned
and falsified
B. A theory is a defined fact, whereas a law is
only a hypothesis
C. Both are true
D. Neither are true
Which is most correct when testing
a hypothesis?
A. If the hypothesis is rejected, the experiment
was a failure
B. The hypothesis can be proven true
C. The hypothesis can be rejected or
accepted
D. All of the above
What happens when there is bias
in an experiment?
Graphs, charts, and calculations
are what form of data?
A. The results are more accurate
B. Personal opinion gets in the way
C. The hypothesis is proved wrong
D. The experiment is not repeatable
A. Variable data
B. Correlation data
C. Qualitative data
D. Quantitative data
Answers
Answer:
#1-c
#2-d
#3-a
#4-a
Explanation:
Describe the characteristics of chytrids and their effect in the amphibian population.
Answers
Chytridiomycota,a phylum of fungi, is characterized by possessing zoopores or motile cells with a single, posterior, whiplash framework or flagellum. They produce gametes adn diploid zoopores that move with the aid of a single flagellum s
Which traits separate fungi from plants?
Answers
We now know that they have unique physical, chemical, and genetic traits that set them apart from plants and other eukaryotes. For example, the cell walls of fungi are made of chitin, not cellulose. Also, fungi absorb nutrients from other organisms, whereas plants make their own food.
Answer:
Fungi don't have chlorophyll and cannot produce their own food, the bodies of fungi are made of masses of filaments woven together, the fungal cell walls contain chitin complex polysacharide.
Explanation:
Why is DNA replication said to be semiconservative? (multiple choice)
A. The old cell keeps part of the original DNA during cell division.
B. The new DNA strand can only be constructed in the 3' to 5' direction.
C. The double helix becomes a single strand of DNA.
D. New DNA has one original strand and one replicated strand.
Answers
how do cells use energy? a) atp hydrolysis b) biosynthesis of more complex molecules c) active transport d) muscle contraction
Answers
Cells use energy by biosynthesis of more complex molecules, active transport and muscle contraction.
Cells do now no longer use the power from oxidation reactions as quickly as it's far released. Instead, they convert it into small, power-wealthy molecules consisting of ATP and nicotinamide adenine dinucleotide (NADH), which may be used at some point of the mobile to strength metabolism and assemble new cell components.
Together, all the chemical reactions that take region internal cells, along with those who devour or generate power, are called the mobile's metabolism. A residing mobile can't save giant quantities of unfastened power.
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What is the term for a heritable feature that allows an organism to survive better
in its environment?
A) homologous structure
B) vestigial structure
C) adaptation
D) variation
Answers
Describe how temperature and salinity affect the solubility of gases in the surface ocean
Answers
Answer:
The solubility of gases such as oxygen and nitrogen depends upon the ocean water's temperature and salinity. As the temperature of the ocean water increases, the solubility of these gases decreases. The solubility of carbon dioxide is greater than the other gases because of its ability to react with ocean water.
which is not a primary effect of central nervous system depressants? group of answer choices reduced inhibition increased respiration rate increased drowsiness reduced muscular coordination
Answers
"increased respiration rate" is not a primary effect of central nervous system depressants.
Central nervous system depressants are substances that slow down brain activity and produce a calming effect. These substances generally produce the following effects: reduced inhibition, increased drowsiness, and reduced muscular coordination. Increased respiration rate is not a primary effect of central nervous system depressants.
Central nervous system depressants work by decreasing activity in the brain, specifically in the areas that control alertness and physical coordination. This can lead to drowsiness, relaxation, and lowered inhibitions, as well as reduced muscular coordination. Central nervous system depressants also have an effect on respiration, but the primary effect is not an increase in respiration rate. In fact, some central nervous system depressants, such as benzodiazepines, can have an effect of slowing down respiration.
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A lab scientist investigating the effect of caffeine on the brain measures the activity of a rat dosed with caffeine. 5.0 seconds after jumping on an exercise wheel, the rat is running in place at 1.4 m/s. The wheel has a .27 m diameter and a mass of 7.5 kg. Model the wheel as a hoop. a) What is the average rotational acceleration of the wheel in the first 5.0 seconds. b) How much work did the rat perform in this period of time?
Answers
What determines if a particle can cross a cell membrane? *
Answers
Answer:
Lipophilic (non-polar molecules), such as steroid hormones or O2 gas can pass... very small uncharged polar molecules (such as H2O, ethanol and urea) can also get through... otherwise you need a membrane protein to "facilitate" the transport of the molecule across the membrane, ion channels are used for water, or charged molecules; carriers/transporters are used for other molecules.
can you please help? :((
Answers
Answer:
2nd one
Explanation:
An experiment is conducted to determine the effects of energy drinks on an individual’s heart rate groups A and B have matched for all factors such as age and sex.Each person in group A is given two red bull energy drinks for breakfast and lunch and then the heart rate is measured.Each person in group B is given water to drink with breakfast and lunch and then their heart rate is measured.Both groups are Fed the same breakfast and lunch the results are recorded
Answers
Answer:
Explanation: this is complicated
What are the 3 domains
Answers
Answer:
Archaea, Bacteria, Eukarya
Answer:
The three domains are Bacteria, Archaea,and Eukarya
Plasmids are important to the genetics of many bacteria. This is because they can render bacteria drug-resistant or they may carry genes that give their host (bacteria) a selective advantage to adapt the environmental changes. Is the statement true or false
Answers
The statement is true. Plasmids are small, circular, double-stranded DNA molecules that are commonly found in bacteria and can confer a variety of advantages to their hosts.
One important role of plasmids in bacteria is their ability to carry antibiotic resistance genes, which can be transferred between bacterial cells and allow them to survive in the presence of antibiotics. This has led to the development of antibiotic-resistant strains of bacteria, which is a major public health concern.
In addition to antibiotic resistance, plasmids can also carry genes that provide a selective advantage to bacteria in specific environments. For example, plasmids may contain genes that enable bacteria to degrade certain compounds, such as pollutants or toxins, or to acquire nutrients that are not readily available in their environment.
Overall, plasmids play a crucial role in the genetics of many bacteria and can contribute to the adaptation and survival of these microorganisms in various environments.
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which of the statements below best describes a gene? group of answer choices a double stranded polynucleotide dna chain. a single nucleotide a chromosome a karyotype
Answers
A gene is a specific section of DNA that is in charge of a character's expression and heredity.
Which one of the following sums up an A gene the best?The ideal choice is B. a certain DNA segment is in charge of character inheritance and expression. A gene is a specific section of DNA that is in charge of the heredity and manifestation of a specific trait.
What can you say about a dna in its most basic form?Response and justification A tract of deoxyribonucleic acid is what a gene is simplest for (DNA). The nucleotide chain in DNA is very lengthy. A nitrogen atom, a phosphate group, and a ribose sugar are all components of each nucleotide. Traits like hair and facial color are encoded by genes.
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DNA carries the cell’s genetic information; however, it cannot leave the __________________. Because of this, it copies part of its nucleotide sequence into a complementary copy of ______________ during the process called _____________________. During this process, ___________Polymerase separates the DNA strands. It then uses one strand of DNA as the __________________ from which nucleotides are assembled into a strand of RNA. Each three letter sequence on the mRNA is called a ______________. The start codon is ____________ and the three stop codons are _____________, ____________, _____________. Once the mRNA leaves the nucleus it goes to the ____________________ to prepare for protein synthesis which is called ___________________. During this process, a ______________ molecule brings the _________________________ to the ribosome. The amino acids are hooked together by ____________________bonds. The tRNA is able to match up to the mRNA by its _______________________. When the stop _________________ is reached, the __________________ chain is released into the ______________________.
Answers
DNA carries the cell’s genetic information; however, it cannot leave the nucleus. Because of this, it copies part of its nucleotide sequence into a complementary copy of mRNA during the process called transcription.
How to illustrate the information?During this process, helicase polymerase separates the DNA strands. It then uses one strand of DNA as the template codon from which nucleotides are assembled into a strand of RNA. Each three-letter sequence on the mRNA is called an AUG. The start codon is ____________ and the three stop codons are UAG UGA UAA.
Once the mRNA leaves the nucleus it goes to the ribosome to prepare for protein synthesis which is called translation. During this process, a tRNA molecule brings the amino acid to the ribosome. The amino acids are hooked together by peptide bonds. The tRNA is able to match up to the mRNA by its complimentary bases. The protein chain is released into the cytoplasm when the stop is reached.
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Help please I have a time
Answers
Answer:
d
Explanation:
your answer is d
Answer:
d
Explanation:
you answer is D
How does an increase in a deer population that feeds on plants affect the animals and plants in a certain environment
Answers
If a deer population starts eating all the plants in a specific area, the plants, of course will kill the plants. But also, once all the plants will run out, all the organisms and deer will eventually die out.
plasma membrane, ribosomes, cytoplasm, and DNA. :(
Answers
plasma is a cell wall
ribosomes make proteins for the cell to use in the nucleus
cytoplasm is cell fluid where the cell grows and replicates
DNA has the instructions telling the cell what to do