The viable plate count is the most commonly used method to estimate the number of viable cells in a sample; while the Petroff-Hausser counting chamber is a direct microscopic count method generally used for counting bacteria and sperm cells.
The Petroff-Hausser counter is a counting chamber used to count microorganisms and cells (e.g., bacteria and spermatic cells) under the microscope.
The Petroff-Hausser counter chamber is divided into 25 large squares which are in turn divided by double lines. Moreover, within each large square, there also are 16 small squares divided by single lines.
Petroff-Hausser counting chambers are often used to directly determine the number of bacteria in a culture or liquid medium. Petroff-Hausser counting chambers are used to count the number of cells in a given volume of culture liquid by observing 10 to 20 microscope fields.
The viable plate count, also known as simply plate count, is the most commonly used procedure to estimate the number of viable cells in a sample.
The viable plate count method consists in obtaining serial dilutions of a sample having viable microorganisms/cells which are plated onto a growth medium.
This method (viable plate count) can be used to determine the number of actively dividing cells.
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1) What is the function of the plasma membrane? (5pts)
2) How does high and low temperature affect a plasma membrane's fluidity? (5pts)
3) How does passive transport differ from active transport? (5pts)
4) What are the three main types of passive transport? Describe each of them. (5pts)
5) List the three types of tonic solutions and describe which way water moves in each one. (5pts)
Answer:
1.Plasma membrane is a semi permiable layer present in a plant cell.it allows only selected substances to pass in and out of the cell.
What could explain how
antibiotics harm bacteria without
hurting the human taking them?
What is the correct chronological order of the steps leading to protein synthesis?
rRNA, mRNA, DNA, protein
mRNA, DNA, rRNA , protein
DNA, mRNA, rRNA, protein
rRNA, DNA, mRNA, protein
Answer:
the third option is the right one.
Explanation:
m RNA gets its information from DNA and then sends it to rRNA which will later turn the message into a protein.
Problems that animal species overcome by their dispersion
killing other animals.........................
2. Why do scientists often use thermoacidophile group of archaebacteria for research?
Archaebacteria have some unique characteristics.
Although members of kingdom Archaebacteria share many characteristics with members of kingdom Eubacteria, some of their characteristics are unique.
One such characteristic is the ability of archaea to live in extreme conditions.
What is Thermoacidophile archaebacteria?Thermoacidophile archaebacteria are a type of archaea that thrive in extremely hot and strong acidic (with low PH) environments. Thermoacidophile archaebacteria can be found in harsh environments such as in geothermal area, in the deep ocean vents and hot springs. Most of the
Thermoacidophile archaebacteria are chemotrophs (converts chemicals to food). They use sulfur as their energy source. They absorb the sulfur gas that is being released in their environment and reduce it to hydrogen sulphide, fixing it into an energy source.
Thus, this could be the answer.
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All of the members of a particular species that live in one area are called a(an):
A) biotope
B) community
C) ecosystem
D) biosphere
E) population
Answer:
Population
Explanation:
population- all the members of one species in a particular area.
draw an animal cell and label it's parts
Explanation:
Labeled Animal Cell!
. ;
Which of the following is NOT a function of behavior?
A. To produce ATP.
B. To find food.
C. To reproduce.
D. To avoid predators.
Answer:
A to produce ATP as you are subconsciously producing ATP and you can not control it
Explanation:
To find food, to reproduce, and to avoid predators all are the functions of behavior except the production of ATP. Thus, the correct option is A.
What are the functions of behavior?Behavior is the range of actions and manners which are made by individuals, systems or artificial entities in a given environment. This can include other systems or organisms as well as inanimate physical environment.
The four main functions of behavior of an organism are attention, escape, access, and sensory needs. These four functions allow us to understand and categorize someone's actions, as well as determine the behavior of organisms such as finding food, reproduction, and avoiding the predators.
Therefore, the correct option is A.
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The development of DNA technology is bringing profound changes to science, agriculture and healthcare. Provide one example of a DNA technology and provide at least one advantage and one example of a concern or problem associated with its use.
Answer:
The CRISPR-Cas9 genome editing system can be used to edit genes and correct mutations associated with inherited diseases. However, this technology also has the potential to edit genes in germline cells in order to irreversibly modify the human species and the natural evolution of life
Explanation:
The CRISPR-Cas9 (Clustered regularly interspaced short palindromic repeats and CRISPR-associated protein 9) system is a natural prokaryotic defense system used by bacteria to defend against invading DNA. In the laboratory, the CRISPR-Cas9 system has been repurposed to create a versatile genome-editing tool that allows us to modify the genome of mammalian cells in a targeted fashion. The CRISPR-Cas9 is a simple gene-editing tool that consists of a single guide RNA (sgRNA) that guides the Cas9 enzyme to the exact genomic location where Cas9 needs to make a cut, which is then repaired by different DNA repair mechanisms. During DNA repair, nucleotides can be replaced and/or deleted, thereby producing desired genomic modifications. The CRISPR-Cas9 has an enormous potential to repair mutations in genes associated with inherited genetic disorders and cancer (i.e., oncogenes might be reversed in vivo by using this technology). However, the CRISPR-Cas9 genome editing system is also a subject of concern due to its dual use. For example, this technology can be used to modify the genome of germline cells by inducing mutations that can be passed across generations, thereby irreversibly modifying human DNA and altering the normal course of evolution.
With increases in CO2 in the atmosphere, _______ are expected to experience the largest temperature increases, while __________ are expected to experience the least.
Answer choices
high latitude oceans; high latitude land surfaces
high latitude land surfaces; low latitude oceans
low latitude oceans; high latitude oceans
low latitude land surfaces; high latitude landsurface
Answer:
The first option would be the best.
Explanation:
The oceans heat up first before the atmosphere does.
what is the full form of ATP?
Answer:
ATP stands for Adenosine triphosphate, an organic molecule responsible for driving nearly all cellular mechanisms and processes in living organisms. Hence, biologists often refer to ATP as the “energy currency of the cell.”
A geneticist finds that a strain of bacteria to produces a non-functional sigma factor. Which among the following steps in transcription would most likely be first affected?
A.Assembly of RNAP onto the DNA strand
B.Identification and binding of RNAP on to the promoter sequence
C.Conversion of open initiation complex to closed initiation complex
D.Synthesis of RNA after the formation of open initiation complex
Answer
D
The transcription factors and RNA polymerase form a complex called the transcription initiation complex. This complex initiates transcription, and the RNA polymerase begins mRNA synthesis by matching complementary bases to the original DNA strand.
How might human anatomy be different today if the forerunners of humans had never inhabited the forest canopy
Explanation:
Humans would likely have never gained opposable thumbs because there would be no need to grasp as well as the shoulders because there would be no reason to move our arms in any direction.
what is photosynthesis
Answer:
The process of making food by Green plants (autotroph) is called photosynthesis. For performing photosynthesis water, sunlight and carbon dioxide are used by the plants.
They take sunlight from sun, water from soil and carbon dioxide gas from the air present around us. The leaves have small holes called stomata which allows air to enter the plant. Leaves also contains chlorophyll in them which traps sunlight and helps in making food. Roots of plants absorbs water and Minerals from the soil and transfers them leaves through stem.
The chemical equation for the photosynthesis
is -
carbon dioxide + water -> glucose + oxygen + energy
[tex] \huge \boxed{\mathfrak{Question} \downarrow}[/tex]
What's photosynthesis?[tex] \large \boxed{\mathfrak{Answer \: with \: Explanation} \downarrow}[/tex]
Photosynthesis is the process in which green plants derive their food (nutrients and water) through the capturing of light energy (sunlight) and using it to convert carbon dioxide (CO2) and water (H2O) into oxygen (O2) and other substances (compounds) that are rich in energy. Chlorophyll a green pigment present in plants is used in this process.
__________________
Formula ⟶ [tex]\boxed{\bf\:6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2} [/tex]
__________________
So, the products of photosynthesis are [tex]\large\boxed{\boxed{\bf\:C_6H_{12}O_6 + 6O_2}}[/tex]
A student is conducting their science experiment on the effects of sugar on bullfrogs. He has 3 groups of test subjects. 1 group of frogs that receives nothing, they are the control group. The 2nd group of frogs receives half a sugar pill each, and the 3rd group receives a whole sugar pill each. He will measure their activity levels and jump heights after giving them the pills. When he is setting up his data table, what should go in the first column?
Answer:
Group 1 of frogs.
Explanation:
It is the first thing because you have to note which of the frogs you're talking about before you start.
Muscle weakness is associated with Vit A/ Vit E/ Vit K/ Protein deficiency
Answer:
Low vitamin E levels may result in Muscle weakness: for the central nervous system, vitamin E is vital. It is one of the major antioxidants in the body and a shortage causes oxidative stress that can lead to weakening in muscles.
Explanation:
The body needs to work with vitamin E and become a necessary vitamin. It is fat-soluble, thus it has to be effectively absorbed in fat from the food. Before being released to the bloodstream for usage, vitamin E is mostly kept in the liver.
The deficiency is unusual and usually caused by an understatement. There are also modest levels of preterm newborns.
Eight kinds of vitamins exist. A blood test allows a physician to know how much a person has of an alpha-tocopherol form. Use this information to establish if the total vitamin E level of a person is present.
A standard level is typically between 5.5 and 17 milligrams (mg/L) per litre. For premature infants and youngsters under 17 years, the typical range may be different. The Normal scope may also be somewhat different amongst laboratories.
If an adult has less than 4 mg/L of vitamin E in his or her blood, supplementation is usually necessary.
4. Which of the following are extra senses that vertebrates may have? (Choose all that apply)
magnetoreception
proprioception
baroception
o nociception
Answer:
- Proprioception
- Magnetoreception
- Nociception
The following are the extra senses that vertebrates may have:
Magnetoreception. Proprioception.Nociception.Thus, the correct options are A, B, and D.
What is Vertebrate?Vertebrates may be defined as those groups of animals that possess a backbone or spinal column. It includes mammals, birds, reptiles, amphibians, and fishes.
Magnetoreception is a sense that allows the organisms to detect the senses of the Earth's magnetic field and responds to it. Proprioception may be defined as a sort of sense that allows your body abilities to sense movement, action, and location.
Nociception may completely depend on the sensory nervous system that process in response to encoding noxious stimuli.
Therefore, the correct options for this question are A, B, and D.
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When the tetrads are formed
during meiosis, what is the
benefit of crossing over?
A. The chromosomes double in number.
B. The chromosomes exchange genetic
information.
C. The chromosomes are reduced by half.
Answer:
B. The chromosomes exchange genetic information.
Explanation:
Crossing over of tetrads during meiosis is very important for the exchange of genetic information.
This step of meiosis allows for each chromosome to be genetically unique and distinct from the others, creating genetic variation.
Crossing over does not double the number of chromosomes or reduce the number. The number of chromosomes stays the same.
So, the correct answer is B. The chromosomes exchange genetic information.
dna is located in the what of the cell and makes up what found there
Explain about Photosynthesis . ?
Answer:
Plants and other creatures utilize photosynthesis to convert light energy into chemical energy, which is then released to power the organism's metabolic processes through cellular respiration.
OAmalOHopeO
Answer:
its basically a process thats plants use and many other organisms to convert light energy into chemical energy that helps them grow and without it, plants would go bye bye . :)
Explanation:
Learned it in science class lol.
. Calculate the 3 difference between food chain and food web
FOOD CHAIN AND FOOD WEB
A linear pathway showing the flow of energy . A multitude of networks showing the flow of energy
An organism of higher level trophic feeds on a specific organism of lower trophic level An organism of higher trophic level has access to more members of a lower trophic level.
Has no effect on the adaptability and competitiveness of organisms. Has a role in improving the adaptability and competitiveness of an organism.
Answer:
A linear pathway showing the flow of energy . A multitude of networks showing the flow of energy
An organism of higher level trophic feeds on a specific organism of lower trophic level An organism of higher trophic level has access to more members of a lower trophic level.
Has no effect on the adaptability and competitiveness of organisms. Has a role in improving the adaptability and competitiveness of an organism
Explanation:
If you compare the histone modifications at the imprinting center on the maternal and paternal chromosomes, you would expect to see ____________ on the maternal chromosome and ____________ on the paternal chromosome.
a. activating marks like H3K9 acetylation; silencing marks like H3K9 methylation
b. silencing marks like H3K9 methylation; activating marks like H3K9 acetylation
Answer:
b. silencing marks like H3K9 methylation; activating marks like H3K9 acetylation
Explanation:
Genomic imprinting is an epigenetic phenomenon that leads to parent-of-origin-specific monoallelic expression, thereby genes under imprinting are differentially expressed depending on their parental origin. Genomic imprinting involves DNA methylation, histone modification such as histone 3 lysine 9 methylation (H3K9) and non-coding RNA regulatory epigenetic pathways, which act together to silence one parental gene form or 'parental allele'. Maternal imprinting occurs when the maternal allele is silenced (usually caused by methylation of the maternal allele), whereas paternal imprinting occurs when the paternal allele is silenced (methylation of the paternal allele). Moreover, H3K9 acetylation is connected with active promoters (gene transcription). The imprinted genes are generally grouped in genomic regions called imprinting centers (ICs) that regulate gene expression according to the parental origin.
Our body needs both vitamin and mineral in a small quantity ,still they are important why?
Answer:
Vitamins and minerals are considered essential nutrients—because acting in concert, they perform hundreds of roles in the body. They help shore up bones, heal wounds, and bolster your immune system. They also convert food into energy, and repair cellular damage.
Which organelle is labeled A?
explain the charge distribution in polar molecule
Answer:
polarity results from uneven partial charge distribution between atoms in a compound
Explanation:
electrons in a polar covalant bond are unequally shared between the two bonded atoms which results in partial positive and negative charges.the separation create a dipole.
The change that occurs at point C could be caused by Multiple choice question. A) increased predation by wolves. B) a wet year with increased vegetative growth. C) increased competition from moose herds. D) a dry year with decreased vegetative growth.
Answer:
The answer is "Option B"
Explanation:
A wet season with increased plant growth is indicated by the fact that the population of Elks from beginning point C attained maximum population size (K100) and remained stable until point D. That's why the difference at point C could be due to the a wet year still higher plant growth.
what is a benefit of genetic engineering?
Answer:
Some benefits of genetic engineering in agriculture are increased crop yields, reduced costs for food or drug production, reduced need for pesticides, enhanced nutrient composition and food quality, resistance to pests and disease, greater food security, and medical benefits to the world's growing population.
Answer:
all benefits:
More nutritious food. increased crop yieldsreduced costs for food reduced need for pesticidesgreater food securityI hope that this helps :)
Which development would most reflect Karl Marx's belief in the economic
system that he predicted would replace free markets?
A. Governments eliminate all taxes on wealthy corporations.
B. Workers share all the profits generated from a factory.
C. Companies begin to sell their products in overseas markets.
D. Businesses refuse to hire workers who demand high wages.
Answer:
D. Businesses refuse to hire workers who demand high wages
Explanation:
Karl Marx's predicted that if businesses refuse to hire workers with high wages according to their value, this can lead to revolution and can destroy or replace the free markets.
Step One: Anatomical Developments
Match the following anatomical developments (A-J) with the number where they occur on the Hominin Anatomy Phylogeny (below).
A. decreased prognathism, moderate sized molars, phalanges not curved (derived), Found in South Africa, still relatively small brain (-450cc)
B. canine reduction, lower jaw tooth row shape intermediate between parallel and parabolic, have footprints explicitly displaying bipedal
patterns, curved phalanges
C. further brain expansion, decrease in teeth size, decrease in brow ridges, flattening of the face, mental eminence, vertical forehead
D. megadontia complex (huge molars, jaws, and chewing muscles), slight increase in cranial capacity (410-530cc)
E. femur and pelvis indicate capable of bipedalism
F. brain expansion, megadontia reduction, smaller less projecting face, smaller jaws
G. occipital bun common, retromolar space, robust postcrania, relatively short limbs
H. further brain expansion, reduction in teeth, face, and jaws, increased brow ridges, increased body size
1. loss of honing complex, obligate bipedalism, curved phalanges (primitive), parallel tooth row shape
J. foramen magnum position indicates likely capable of bipedalism
A. Hoomo ergaster & Hoomoo erectus
B. Hoomoo erectus
C. Hoomoo ergaster
D. Hoomoo Habilis
E. Hoomoo ergaster and Hooomo erectus
F. Hoomo Habilis
G. Hoomoo erectus
H. Hoomoo ergaster
I. Hoomoo ergaster and Hoomoo erectus
J. Hoomoo erectus
Homooo erectus fossils are found in China and Indonesia. They have widest part of brain case at cranial base.
They have reduced post canine and decrease jaw size. They have shorter forelimbs and are bipeds.
Homooo habiliss are dimorphic species which have long forelimbs and shorter forelimbs.
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Una de las aplicaciones más importa del electromagnetismo son
Answer:
Las principales aplicaciones del electromagnetismo se emplean en: La electricidad. El magnetismo. La conductividad eléctrica y superconductividad.
Explanation:
