Answer:
b.
viruses may have been the first self-replicating entities
Explanation:
The “virus-first” hypothesis states that viruses predated cells and contributed to the rise of cellular life. A significant proportion of all the viral genomes encode for genetic sequences that lack clear cellular homologs. Presence of such virus-specific sequences provides support to their unique origin.
TRUE or FALSE
Visible light has very short wavelengths.
If FALSE explain:
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Chemostat culture with protozoa Tetrahymena thermophila protozoa have a minimum doubling time of 6.5 hours when grown using bacteria as the limiting substrate. The yield of protozoal biomass is 0.33 g per g of bacteria and the substrate constant is 12 mg l1 . The protozoa are cultured at steady state in a chemostat using a feed stream containing 10 g l1 of nonviable bacteria. (a) What is the maximum dilution rate for operation of the chemostat
Answer:
The correct answer is - 3.3 g/L.
Explanation:
It is known that if endogenous metabolism is not important then,
µnet = µmax = 0.693/doubling time.
Given:
doubling time = 6.5 hr, therefore,
µmax = 0.693/6.5 = 0.1/h
Formula:
First, maximum dilution rate Dmax,
Dmax = µmax*[S0]/{Ks + [S0]}.........(1)
Steady-state cell concentration, X
X = Yx/s{[S0] - KsD/(meumax - D)..........(2)
Solution:
Yx/s = 0.33 g/g-substrate;
Ks = 12 x 10-3 g/L; [S0] = 10g/L,
puting value in (1)
Dmax = 0.1 * 10 / (12 x 10-3 + 10)
= 0.1/h.
Now it is given that operating D is 1/2 of Dmax, therefore,
D in our case will be = 0.05/h
concentration of protozoa cells from equation (2).
Therefore, X = 0.33*{10 - 12 x 10-3 * 0.05/(0.1 - 0.05)} = 3.3 g/L.
A rabbit population's birth rate is 200 rabbits born/year. The death rate is 150 rabbits dying/year.
Is the population of rabbits growing or shrinking? Explain by calculating the growth rate.
Answer:
It's growing
Explanation:
The growth rate is 50 rabbits per year
2. How much is the average temperature at depth of 10 km of earth surface?
A) 200 °C
C) 650°C
B) 900°C
D) 20°C
The average temperature at depth of 10 km of the earth's surface is 200°C. Thus, the correct option is A.
What is the average temperature?An average temperature may be defined as the annual mean temperature of any geographical location which is estimated approximately by the average temperature of the maxima and minima for the warmest and coldest months of the year.
It is the principle that the increase in the depth below the surface of the earth ultimately leads to the rising of average temperature. This is due to the process of apparent heat.
It may be possible that higher or lower temperatures also occur. but the average temperature at depth of 10 km of earth surface should approximately remain 200°C. It is a factual type of question.
Therefore, the average temperature at depth of 10 km of the earth's surface is 200°C. Thus, the correct option is A.
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20. Process through which pollutants get increasingly more concentrated each step up the food chain.
bloaccumulation
risk assessment
toxicity
biomagnification
Answer:
bioaccumulation of chemicals is the problem concerning all living organisms. This is the result of dynamic equilibrium between the uptake and elimination. The extent to which bioaccumulation occurs determines the toxic effects which are manifested. In some cases, the mechanisms of protection from certain undesirable substances deposited in special sites, to prevent their participation in the metabolic reactions, have evolved. The knowledge on bioaccumulation enables to assess the risk related with the presence of various chemicals in the environment, food, and at workplace and to present quantitatively the ability to control the use and emissions of chemicals.
Factors that control traits are called?
a. genes.
b. purebreds.
c. recessives.
d. parents
Answer:
A. Genes
Explanation:
What is the primary goal of human communities?
O A. To safeguard human culture and language
O B. To satisfy human needs by working together
O c. To make and follow rules through political organization
O D. To understand group behavior through observation
following the laws of Convervation of matter, 10 grams of iron combined with 5 grams of sulfur will yield _____ grams of iron sulfide
Answer:
15
Explanation:
Since the law of conservation of mass applies to all the chemical reactions this will also end in 10+5 equalling 15 grams
where does the second step in making a protein occur?
Answer:
ribosome in the cytoplasm
Explanation:
The second step in making a protein occurs in the ribosome in the cytoplasm.
What is the function of histones- proteins that aide in dna replication
Answer:
Nucleosomes in turn are wrapped into 30-nanometer fibers that form tightly packed chromatin. Histones prevent DNA from becoming tangled and protect it from DNA damage. In addition, histones play important roles in gene regulation and DNA replication. Without histones, unwound DNA in chromosomes would be very long.
Cells convert food into usable energy in a structure known as the powerhouse of the cell, or the ________. vacuole vacuole chloroplast chloroplast nucleus nucleus mitochondria
Answer:
Mitochondria are the "powerhouses" of the cell, breaking down fuel molecules and capturing energy in cellular respiration. Chloroplasts are found in plants and algae. They're responsible for capturing light energy to make sugars in photosynthesis
Crossing over plays a critical role in increasing the genetic variation among offspring of sexual reproduction.
a. True
b. False
Answer:
T
Explanation:
I Got It Right.
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The trees in a forest were cut down to make room for a housing development. Explain how this impacts the environment.
The interaction of the skeletal and muscular systems for movement is coordinated by which human body system.
A. Circulatory
B. Excretory
C.Respiratory
D.Nervous
Answer:
D: Nervous system
Hope this helps!
why is the air temperature in the rain forest of Peru so warm?
Answer:
Because Peru is located between the equator and Tropic of Capricorn. Since it is in the tropics, one might expect Peru to be a country of extreme heat and heavy vegetation.
Explanation:
Which cell division phase is shown in the image?
A) metaphase
B) anaphase
C) prophase
D) telophase
Answer:
a
Explanation:
metaphase - the chromosome line up at the equator
Answer:
C. Anaphase
Explanation:
During anaphase, the chromatids line at the center
Land breeze happens at night.
A. True
B. False
Answer:
true
Explanation:
the answer is A
land breeze is the opposite of sea breeze.
sea breeze accurs during the day
Land breeze occurs during night
Explain two (each) methods of micro-organism control for Malaria and Rabies
Explanation:
Vaccination and use of quinine drugs
Please help honest answers only!! How could wildfire immediately impact competition in a forest ecosystem? (1 point)
Competition would decrease. Many ecosystems rely on wildfire to restore nutrients and germinate seeds; therefore, wildfire would
increase resources available, lowering competition
Competition would increase. Wildfire would increase the scarcity of resources, causing individuals to compete at higher rates.
Competition would remain the same. Wildfire would increase the scarcity of resources and decrease individuals competing.
effectively balancing each other out.
Competition would decrease. Wildfire would decrease the number of individuals competing for resources, making more resources
available per individual.
Answer:
I think its b. Competition would increase. Wildfire would increase the scarcity of resources, causing individuals to compete at higher rates.
Explanation:
not 100% sure tho
Wildfires can immediately impact competition in a forest ecosystem because wildfires would increase resource scarcity, causing individuals to compete at higher rates.
What are the consequences of forest fires?In addition to destroying native vegetation and killing many wild animals, a forest fire can also cause serious financial damage and even endanger the lives of people and domestic animals.
With this information, we can conclude that wildfires can immediately affect competition in a forest ecosystem because wildfires would increase resource scarcity, causing individuals to compete at higher rates.
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The table shows data Chargaff collected on DNA nitrogenous bases in five organisms.
Percentages of Bases in Five Organisms
Source of DNA A T G C
Streptococcus 29.8 31.6 20.5 18.0
Yeast 31.3 32.9 18.7 17.1
Herring 27.8 27.5 22.2 22.6
Human 30.9 29.4 19.9 19.8
E.coli 24.7 23.6 26.0 25.7
Which statement did Chargaff conclude based on these data? Note that a letter in brackets, such as [A] or [C], refers to the concentration of one of the nitrogenous bases.
A. in DNA molecules, [T] > [A] > [G] > [C]
B. in DNA molecules [A] = [G], and [C ] = [T]
C. in DNA molecules, [A] = [T], and [C ] = [G]
D. in single-stranded DNA molecules, [A] = [T] = [C ] = [G]
Answer: in DNA molecules, [A] = [T], and [C ] = [G]
Explanation:
If all the offspring of a particular cross have the genotype Gg, what must the genotype of the parents be?
Answer:
GG and gg
Explanation:
Crossed extensor reflex is a
Answer:
The crossed extensor reflex is a type of motor response that occurs to tactile stimulation of a lower limb. This, like other reflexes, is an indication of the proper integration and development of the central nervous system.
Explanation:
Stimulation on one side of the body can produce, in addition to the ipsilateral response. The crossed extensor reflex is a type of motor response, reciprocal innervation is involved: the flexor muscles of the stimulated limb contract at the same time that the extensors of said limb are inhibited. Coupled with flexion of the stimulated limb, the reflex produces an opposite effect in the contralateral limb: the extensor muscles are activated and the flexors are inhibited, this cross-extension reflex increases postural support during withdrawal of the painful stimulus.
Which would be an adaptation for living in the tundra?
funnel shaped leaves to help water runoff
deep roots to go into the permafrost
hibernation to lower metabolism in the winter
large ears to release heat
Answer:
C: Hibernation to lower metabolism in the winter
Explanation:
Answer:
C is correct
Explanation:
PLEASE HELP!!
Which of these is necessary for gas exchange in the respiratory system?
a.At least 30% oxygen in the air
b.The exchange surface must be moist c.The air must be cooler than body temperature
d.The blood cannot be moving
Write the tRNA anticodons for the following strand of mRNA.
AGA GAU UCA GCU AGC ACG AUA
Answer:
UCU CUA CGA UCG UAU
Explanation:
Those are the answers above.
Which best summarizes the article? achieve 3000 New Life at. Yellowstone
A. New life has appeared in Yellowstone 20 years after wildfires scorched the park
B. Wildfires burned 1375 square miles (4 856 square kilometers) in and around Yellowstone Park in 1988
C. Oficials in Yellowstone re examined a policy that allowed wildfires in the park
D. Drought once dried out trees in Yellowstone and helped fires spread out of control
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A sequence of RNA is shown below:
CAA AAU GCG AUC 3
Using the codon chart below, what is the sequence of amino acids that is produced when this RNA is translated?
Choose 1 answer:
(Choice A)
A
Gln - Asn - Ala - Ile
(Choice B)
B
His - Asn - Ala - Met
(Choice C)
C
Gln - Asn - Pro - Tyr
(Choice D)
D
Val - Leu - Arg - Stop
Answer:
Choice D
Explanation:
When you translate the RNA, you replace C’s with G’s (and vice versa) and A’s with U’s (also vice versa). So, you get GUU UUA CGC UAG. Then you read the codon chart to get your answer. Hope it helps :)
The sequence of the amino acids which is being produced when this RNA is translated is Val - Leu - Arg - Stop. Thus, the correct option is D.
What is a Codon?Codon can be defined as the sequence of three consecutive nucleotides in the nucleic acids such as a DNA or RNA molecule which codes for a specific amino acid. Certain codons are responsible for the signal of the start or end of the translation process.
Codons are universal in nature throughout the different living organisms. There are about 64 different codons which codes for 20 standard amino acids in the cell. There are three stop codons in the genetic code which stop the process of translation of protein molecules including UAG, UAA, and UGA.
The sequence of the amino acids which can be produced when this RNA is translated 5'-CAA AAU GCG AUC-3' will be Val - Leu - Arg - Stop.
Therefore, the correct option is D.
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Answer:
synthetic:.
chemically processed
not environmentally friendly
durable
nylon polyester plastic
resistance to insect
natural
natural obtained
environmentally friendly
not durable
cotton
food for insect
I am not sure about wool and food for insect sorry
hope it helped
Scientists conduct many types of scientific investigations. Their efforts often include fieldwork, surveys, models, and experiments. Which statement about scientific investigations is true?
They rarely involve the collection of data under controlled conditions.
They follow exactly the same steps because there is only one scientific method.
They include multiple trials to increase the consistency of the data that are collected.
Their primary focus seldom includes comparing or describing the unregulated world.
Migrating fibroblasts can be treated with various chemical agents while they are migrating. Explain what you expect for each of the following conditions.
a. The cells are injected with large amounts of purified gelsolin, and the live cells are observed periodically.
b. The cells are treated with latrunculin A, the drug is washed out, and the live cells are observed periodically.
c. The cells are treated with a chemical fixative and prepared for electron microscopy. Their actin filaments are decorated with myosin S1 subfragments, and you examine in which direction the arrowhead-shaped decorations are pointing in the filopodia of the fixed cells.
Answer:
c
Explanation: