The prenatal period begins soon after fertilization and continues till the childbirth.
Prenatal period refers to the time period when the development of the zygote takes place into a complete organism. This period differs in different species. In humans, the prenatal period is of 9 months. The prenatal period is further divided into three stages: germinal, embryonic, and fetal.
Fertilization is a part of the reproduction process where the male gamete and the female gamete fuse with each other to form a diploid single cell called zygote. The fusion occurs of the nuclei of both the cells inside the cytoplasm of female gamete. Fertilization can be internal or external.
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microscopic membrane extensions that extend from the plasma membrane are called?
Microvilli are finger-like membrane protrusions, which can be extended from plasma-membrane.
What are extensions of plasma-membrane into cell wall?
The expansion of plasma-membrane into cell wall creates mesosomes. This results in formation of vesicles, tubules, and lamellae, among other irregularly folded geometries. Some bacteria, primarily gram-positive bacteria, include mesosomes. These play a crucial role in a number of functions, including the production of cell walls, DNA replication, distribution to daughter cells, respiration and secretion. Respiratory pigments that are involved in bacterial respiration are found in mesosome.
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The role of the chordae tendineae is to open the AV valves at the appropriate time. (T/F)
True, chordae tendineae opens the AV valves at the approximate time.
What are chordae tendineae?The chordae tendineae are small, string-like structures that attach the cusps of the AV valves to the papillary muscles of the heart. When the ventricles contract, the papillary muscles contract, which pulls the chordae tendineae tight and causes the AV valves to open. This allows blood to flow from the ventricles into the atria. When the ventricles relax, the papillary muscles relax and the chordae tendineae loosen, which causes the AV valves to close, preventing blood from flowing back into the ventricles.
They are an essential part of the cardiac cycle that plays an important role in maintaining normal blood flow. Without them, the AV valves would not open and close properly, which could lead to abnormal blood flow, heart murmurs, and even heart failure.
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how can carcinogens in cigarette smoke increase cell division, inhibit dna repair, and prevent cells from dying?
The carcinogens which are present in the cigarette smoke are able to cause necessary mutation in the DNA which cause an increase in the cell division, inhibition of the DNA repair and also helps the cells from dying.
Carcinogens are basically defined as cancer causing agents. Cancer is any disease in which the normal cells are damaged and get transformed to form cancer cells and do not undergo any programmed cell death as fast as they divide through mitosis.
Tobacco products as well as smoke happens to contain many chemicals that can possibly damage DNA. Multiple repair pathways exist in our body which can protect a human cell against these mutagenic and carcinogenic agents.
The carcinogens which are present in the cigarette smoke are able to cause necessary mutation in the DNA which cause an increase in the cell division, inhibition of the DNA repair and also helps the cells from dying.
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the plates you are using for this lab will be autoclaved to completely sterilize them. the measures taken to disinfect the tabletops (the source of the organisms on plates 2 and 3) are not as extreme. why?
In this case- the agar plates were used to GROW bacteria on them they have become a bio-hazard. The tabletop is easily disinfected with alcohol or many other chemicals.
A biological substance that endangers the health of living things, especially humans, is referred to as a biological hazard or biohazard. A sample of a microorganism, virus, or toxin that can be harmful to human health may be included in this. A substance poisonous to other animals can also be considered a biohazard.
The term and its corresponding symbol are typically used as a warning so that people who may be exposed to the substances are aware of the need for safety measures. Charles Baldwin, an environmental-health engineer working on the containment products for the Dow Chemical Company, created the biohazard symbol in 1966. [1]
It is applied to the labeling of biological items that pose a serious health risk, such as used hypodermic needles and viral samples.
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in gene expression, how is the promoter different from the start codon?
Start codons are the first bases that are translated on an mRNA, whereas promoters are the regions of DNA where transcription begins.
A promoter sequence must precede a gene for it to be transcribed. The attachment recognition site of the transcription enzyme RNA polymerase can be found here. An initiator sequence comes after the promoter sequence, indicating the location where m-RNA transcription begins. On m-RNA, the sequence AUG, which is also codon 1 and corresponds to the amino acid methionine, is the initiator codon or start signal. Additionally, it marks the beginning of translation.
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Question 6
14.3 pts
Let's test your understanding of the limitations of scientific models. Here are four
statements that involve scientific models. Choose the correct statement, based on
what you just learned.
One model of Earth's climate predicts that global temperatures will rise by 2.5-5.0 F. The
model gives a range, because there are some uncertainties about future human behavior.
O A model that is not exactly correct is useless.
An evolutionary model says that orangutans evolved between 12 and 16 million years ago.
Because this model does not give an exact value, it must be wrong.
OIf I cross two pea plants and get something slightly different than predicted by Mendel, his
model should be thrown away because it is incorrect.
The student's claim did not follow the scientific method of discovery, hence, it is an opinion not a scientific claim.
What is the scientific method?The scientific method is a procedure employed by scientific towards understanding the world around them as well giving explanation for phenomena in the natural world.
The scientific method involves:
observationsasking questionsputting forward a hypothesistesting the hypothesis through experimentsanalyzing results of the experiments and drawing conclusionsestablishing a theory.Since, the student in question just put forward an opinion without testing it out using the scientific method, the statement is not a scientific claim.The student's claim did not follow the scientific method of discovery, hence, it is an opinion not a scientific claim.
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in addition to activating or inhibiting enzymes through allosteric regulation, what other means does a cell use to control enzymatic activity? question 29 options: assembly of enzymes into large aggregates altering internal ph secretion of enzymes out of the cell localization of enzymes into specific organelles or membranes
RNA polymerase translating RNA. It forms the sequence 3' GACU 5' by replicating the same sequences as it passes through the region highlighted in bold red.
In order to employ one strand of RNA polymerase and the exposed nucleotides as a template for the transcription of RNA, the RNAP enzyme uses helicase to locally open the double-stranded DNA. Before RNAP can start the DNA unwinding at a specific location, a transcription mediator complex, and a transcription factor must be connected to a DNA binding site known as a promoter region. In addition to starting RNA transcription, RNAP also guides nucleotides into place, promotes attachment and elongation, functions as an integrated replacement and proofreader, and has the ability to recognize terminations. RNAP can create chains in eukaryotes that are up to 2.4 million nucleotides long.
The complete question is:
What other mechanisms does a cell employ to regulate enzymatic activity besides activating or inhibiting enzymes through allosteric regulation?
A) the placement of enzymes within particular organelles or membranes
B) secretion of enzymes out of the cell
C) assembly of enzymes into large aggregates
D) altering internal pH
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what is the structure and function of the cell wall
the release of hormones by the adrenal glands is most likely to trigger
The hormone released by the adrenal glands is most likely what causes the fight-or-flight response, also known as the acute stress response.
This reaction is the body's natural physiological response to perceived danger; it gets the body ready to defend itself or run away. It is characterized by an increase in heart rate, blood pressure, breathing rate, and muscle strength as well as the release of the stress hormones cortisol and adrenaline.
Individuals are shielded from harm and assisted in reacting quickly to dangerous situations by this response. The "fight or flight" response is a physiological reaction that can be brought on by the adrenal glands releasing hormones. This reaction is triggered by perceived stress or danger and primes the body to react to the perceived threat.
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Which image shows a nonrenewable resource?
A plant
An aluminum nugget
Wood
Energy from the sun
The image which shows a nonrenewable resource is an aluminum nugget and is therefore denoted as option B.
What is a Nonrenewable resource?This is referred to as a natural resource that cannot be readily replaced by natural means at a pace quick enough to keep up with consumption and it includes substances such as metals, fossil fuels etc.
We should note that aluminum nugget is made up of a metal and cannot be replaced by natural means which us why recycling of these substances occur in other to meet up with the demand thereby making it the correct choice.
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which of the following is not true of persistent viral infections? which of the following is not true of persistent viral infections? disease process occurs gradually over long period continuous, low-level viral shedding for months or years none of the other four answers (all are true of persistent viral infections) prolonged, ongoing slow replication of a virus over a long time a virus or its nucleic acid remains inactive (non-replicating) in the host
The statement "a virus or its nucleic acid remains inactive (non-replicating) in the host" is not true of persistent viral infections.
Persistent viral infections are characterized by the prolonged, ongoing replication of a virus over a long period of time.In persistent viral infections, the virus is able to replicate within the host without causing significant harm to the host. This allows the virus to persist in the host for long periods, sometimes even for the lifetime of the host.
As a result, the host is able to continuously shed the virus, leading to a low-level of viral shedding for months or years.The disease process in persistent viral infections occurs gradually over a long period, as the virus replicates and spreads within the host. The long-term replication of the virus can lead to a gradual decline in the host's health, but the decline is often slow and subtle.
In conclusion, "a virus or its nucleic acid remains inactive (non-replicating) in the host" is not true of persistent viral infections. Persistent viral infections are characterized by the prolonged, ongoing replication of a virus in the host.
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which of the following exemplifies genetic recombination? multiple choice question. an offspring receives a combination of alleles identical to those in the p generation an offspring receives a combination of alleles that differs from those in the p generation
An offspring receives a combination of alleles that differs from those in the P generation exemplifies genetic recombination.
The exchange of genetic material between distinct organisms, commonly referred to as genetic recombination or genetic reshuffling, produces offspring with features that are different from those of either parent. In eukaryotes, meiosis-induced genetic recombination can produce a unique set of genetic material that can then be transferred from parents to children.
The majority of recombination happens naturally and can be divided into two types: intrachromosomal recombination, which occurs by crossing over, and interchromosomal recombination, which occurs through independent assortment of alleles whose loci are on distinct but homologous chromosomes.
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Which of the following exemplifies genetic recombination?
How do transposable elements contribute to genome evolution?
Explanation:
Transposable elements (TEs) are DNA sequences that are capable of integrating into the genome at a new site within the cell of its origin. Sometimes, the change in their positions creates or reverses mutations, thereby altering the cell's genotype.
what type of bonds form between the codon of mrna and the anticodon of trna?
Hydrogen bonds are the types of bonds which are formed between the codon of the mRNA and the anticodon of the tRNA.
A particular site which is present on each of the tRNA forms a three base anticodon which is found to be complementary to a specific codon present on the mRNA.
Hydrogen bonds are the type of bonds which are required to bind the complementary bases which are present on codon as well as on the anticodon together. On the mRNA, codon happens to form hydrogen bonds with a tRNA anticodon site. The ribosome is able to allow the tRNA to be bound to the mRNA which is bearing a particular complimentary amino acid.
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an individual comes to the blood bank as a donor for plasmapheresis. he previously donated plasma 8 weeks ago. his pulse rate is 80 beats per minute; blood pressure 120/80; hct is 40%. what is the next course of action? group of answer choices
The individual who has come to blood bank as a donor for plasmapheresis, has the pulse rate is 80 beats per minute; blood pressure 120/80; HCT is 40%. and therefore we will accept the individual as a donor.
Plasmapheresis is basically a method which is used for removing blood plasma from the body. It first involves withdrawing the blood, then separating it into plasma as well as cells and then transfusing the cells back into the bloodstream. It is performed especially to remove antibodies in order to treat many autoimmune conditions.
There are certain conditions which should be met before accepting a blood donor for plasmapheresis. Since the individual has the pulse rate is 80 beats per minute; blood pressure 120/80; HCT is 40%, we can accept them as a blood donor.
--The given question is incomplete, the complete question is
"An individual comes to the blood bank as a donor for plasmapheresis. he previously donated plasma 8 weeks ago. his pulse rate is 80 beats per minute; blood pressure 120/80; HCT is 40%. What is the next course of action? a. Accept him as a donor b. Reject him as a donor c. Cannot be determined."--
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who formulated the hypothesis that certain chemicals could kill microbes without harming humans was the foundation for chemotherapy?
Ehrlich. German chemist and physician Paul Ehrlich (1854–1915) set out in the early 1900s to find or create chemical compounds that might kill infectious microorganisms without injuring the patient.
Sahachiro Hata, Ehrlich's assistant (1873–1938), discovered one such "magic bullet" in 1909 after screening more than 600 compounds containing arsenic. Chemical 606 was intended to kill the syphilis-causing bacteria Treponema pallidum. When it was discovered that compound 606 effectively treated syphilis in rabbits, it was utilized to develop salvarsan, a drug used to treat syphilis in people. Ehrlich's innovative method of painstakingly screening a wide range of chemicals is still a crucial part of the hunt for novel antimicrobial agents today.
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Who formulated the hypothesis that certain chemicals could kill microbes without harming humans was the foundation for chemotherapy?
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You have 2 samples, each containing a different DNA fragment. The fragments are the same size but have different sequences. You know what the sequence should be for each sample, but the labels have worn off and now you don’t know which sample is which. How could you use restriction enzymes to determine which tube contains which DNA sample?
please help, urgent!!
You can use restriction enzymes to determine which tube contains which DNA sample by performing restriction digest on each sample using the same restriction enzyme.
How does restriction enzyme work?If the restriction enzyme cuts the DNA fragments into smaller pieces, the resulting fragments will be different for each sample based on the sequence of each fragment.
By analyzing the pattern of fragments produced from the restriction digest, you can determine which sample corresponds to the known sequence. This can be confirmed by comparing the fragments to a reference DNA ladder or by sequencing the fragments.
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Which function does tRNA serve in a cell?
O combines with proteins to form a ribosome
O bonds amino acids together to form proteins
O collects amino acids for translation
O carries genetic information to ribosomes
O transports amino acids to ribosomes. During the translation process, transfer RNA (tRNA) transports certain amino acids to the ribosome, where they are joined together to form a protein. The information encoded in messenger RNA guides this process (mRNA).
What is RNA?Ribonucleic acid is a polymeric molecule that plays important functions in gene coding, decoding, regulation, and expression. Nucleic acids include RNA and deoxyribonucleic acid. Ribonucleic acid (RNA) is a nucleic acid found in all living cells that is structurally identical to DNA. RNA, unlike DNA, is typically single-stranded. Instead of the deoxyribose present in DNA, the backbone of an RNA molecule is formed of alternating phosphate groups and the sugar ribose. RNA's principal job is to generate proteins through translation. RNA provides genetic information, which ribosomes transcribe into diverse proteins required for biological functions. The three primary forms of RNA involved in protein synthesis are mRNA, rRNA, and tRNA.
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what characterizes depolarization, the first phase of the action potential?
Depolarization is a change within a cell, during which the cell undergoes a shift in electric charge distribution, resulting in less negative charge inside the cell compared to the outside. Depolarization is essential to the function of many cells, communication between cells, and the overall physiology of an organism.
Cell depolarization, or membrane depolarization, is a process that shifts the electrical charge distribution so that the cell is less negatively charged compared to the environment. In other words, during depolarization, the membrane potential becomes less negative. Cell depolarization is crucial because it allows cells to send messages quickly and in a uniform way. It also allows for fast communication over long distances in the body.
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Why is freezing water considered a physical change and not a chemical change?
Water that has been frozen is said to have undergone a physical change since there has been no change in the substance's chemical makeup. Physical modifications are those that influence a substance's size, shape, and form without changing its chemical identity.
They also impact a substance's state of matter, size, and other physical characteristics. When water freezes, a shift in pressure and temperature causes the liquid water to turn into solid ice. Water has the same chemical make-up in both its solid and liquid forms, and its chemical linkages are same in both.The production of new compounds with differing chemical and physical characteristics occurs during chemical changes, in contrast. The outcome of chemical reactions is a change in thechemical make-up of a material as new and broken bonds are generated between its molecules and atoms. As a consequence, substances that were not the original substances are produced.In conclusion, the type of change that occurs is what distinguishes a physical change from a chemical change.
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Since the chemical makeup of frozen water has not changed, the substance is said to have undergone a physical change. Physical alterations are those that affect a substance's dimension, form, and appearance without altering its chemical composition.
They affect a substance's size, state of matter, and other physical attributes as well. A change in temperature and pressure causes liquid water to solidify into ice when it freezes. Both in its solid and liquid states, water has the same chemical composition and chemical linkages. Contrarily, during chemical changes, new compounds are created with distinct chemical and physical properties.
A material's chemical composition changes as a result of chemical reactions because new and broken bonds are formed between its molecules and atoms.
As a result, materials that weren't the original materials are created. In conclusion, a physical change differs from a chemical change based on the type of change that takes place.
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A mechanism by which experts in a field carefully screen the work of their colleagues is known as ____________.
A) experimental validity
B) experimenter bias effect
C) peer review
D) peer assessment
C) peer review
What is peer review?
Peer review is a process by which subject matter specialists thoroughly scrutinize the work of their peers. Peer review's objective is to verify that research findings are accurate and of high quality by having other authorities in the same field assess them. Peer review is a process where experts in the field assess a research study's procedures, findings, and conclusions objectively and offer helpful criticism to the authors. This assists with enhancing the research's quality, boosting its reputation, and locating any errors or biases that might be present. Peer review is a crucial step in the scientific method and is utilized in many disciplines, such as biology, physics, psychology, and medicine.
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can you match terms related to operons to their definitions? drag the terms on the left to the appropriate blanks on the right to complete the sentences. view available hint(s)
1. An operon, which typically makes up an entire metabolic pathway, is a segment of DNA that contains an operator, a promoter, and genes for a related group of proteins.
2. Following the promoter, the genes of an operon are organized sequentially.
3. An RNA polymerase binds to a particular nucleotide sequence in DNA known as a(n) promoter, positioning it to begin RNA transcription at the proper location.
4. A gene called a regulatory encodes a protein called a repressor that regulates the transcription of another gene or set of genes.
5. Regulatory proteins bind to the operon to regulate operon expression.
6. A protein called a repressoris prevents the transcription of genes. This protein binds to the DNA within or close to the promoter in prokaryotes.
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Bacteria and archaeans are similar in all of the following ways except _____.
(a) they are both relatively small compared to eukaryotic cells
(b) they both reproduce rapidly
(c) they both have complex membrane-bound organelles
(d) they both lack a true nucleus.
Bacteria and archaeans do not consist of complex membrane bound organelles in their cell bodies.
The correct option is option c.
A prokaryotic cell is basically a simple as well as single-celled or we can say unicellular organism which lacks a nucleus and any other membrane-bound organelle. Prokaryotic DNA is basically found in the central part of the cell which is a darkened region known as the nucleoid.
Bacteria and archaeans are both relatively small in size when compared to eukaryotic cells. They both are able to reproduce rapidly and lack the presence of a true, well-defined nucleus. They also do not have complex membrane bound organelles.
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if you have a small amount of a large chromosome of 20 million bp and want to amplify a short sequence of 1000 bp how would you do it
Since chromosomes primers are the starting point of DNA replication, a primer would be placed after the 1,000 bp in order to amplify it. The rounds of replication will gradually increase the 1,000 unaffected.
A given DNA segment can be quickly multiplied (amplified) into millions or billions of copies using the polymerase chain reaction (abbreviated PCR), allowing for more in-depth analysis. The enzymatic replication of DNA serves as the foundation for the PCR method. In PCR, primer-mediated enzymes are used to amplify a brief piece of DNA. A quick and accurate way to duplicate genetic material is through PCR.
The complete question is:
If you have a small amount of a large chromosome of 20 million bp and want to amplify a short sequence of 1,000 bp, how would you do it? Explain the role of primers in this process.
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Select all inheritance patterns in which 50% of the functional protein is sufficient to produce a wild-type phenotype: 1) Simple Mendelian dominant alleles 2) An X-linked dominant allele in a heterozygous female 3) Haploinsufficient genes 4) Incomplete dominance
The inheritance patterns in which 50% of the functional protein is sufficient to produce a wild-type phenotype are: Haploinsufficient genes and X-linked dominant allele .
Haploinsufficient genes: In haploinsufficient genes, a single copy of a functional allele is sufficient to produce a wild-type phenotype. This is because the presence of a single functional allele produces enough functional protein to perform its normal cellular functions.
X-linked dominant allele in a heterozygous female: In this inheritance pattern, a dominant allele located on the X chromosome results in a wild-type phenotype when present in a heterozygous female. This is because females have two X chromosomes, so the presence of a single functional allele on one X chromosome is sufficient to produce enough functional protein to produce a wild-type phenotype.
These inheritance patterns contrast with Simple Mendelian dominant alleles and incomplete dominance, in which both copies of the allele must be functional to produce a wild-type phenotype. In simple Mendelian dominant alleles, an individual with a single dominant allele will express the dominant phenotype. In incomplete dominance, neither allele is completely dominant, and a blend of the two alleles' phenotypes is expressed.
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What is the momentum of a 54 kg dog with a velocity of 4 m/s.
Science
Answer: 216 kg·m/s
Explanation: Momentum Calculator
The simplest and most rapid method of producing atp during exercise is through?
The simplest and most rapid method of producing ATP during exercise is through ATP-CP system.
In order to regenerate ATP, the ATP-PC system makes use of a substance known as creatine phosphate (CP), which is stored in the muscle. It is only through the destruction of this molecule that one can obtain the energy necessary to recombine ADP with free phosphate in order to produce ATP. This process is considered anaerobic since it does not require the presence of oxygen to function and it does not generate any waste products. This system gives us rapid access to energy, but it has a very low capacity and can only keep us going for around 10 to 12 seconds at a time.
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a man with blonde hair, blue eyes, and fair skin has a daughter with a woman with dark hair, brown eyes, and dark skin. (assume that hair, eye, and skin color are each dependent on a single gene.) based on their differences in these three traits, how many possible phenotypic combinations are possible for their child? a
There would be 12 possible phenotypic combinations for hair, eye, and skin color.
Hair color, eye color, and skin color are each dependent on a single gene with multiple alleles, and each of these traits is controlled by a different set of genes.
Blonde hair is typically associated with the B allele, while dark hair is typically associated with the b allele. Blue eyes are typically associated with the E allele, while brown eyes are typically associated with the e allele. Fair skin is typically associated with the S allele, while dark skin is typically associated with the s allele.
Based on this information, the man would be homozygous for the BbEeSs genotype, while the woman would be homozygous for the bbeess genotype.
The possible phenotypic combinations for their child would be BbEe, BbEe, BbEe, BbEe, bbEe, bbEe, bbEe, bbEe, BbeEe, BbeEe, bbeEe, and bbeEe, resulting in 12 possible phenotypic combinations for hair, eye, and skin color.
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which of the following is true regarding the use of the dark field microscopy. question 11 options: a) this can be used to view live organisms. b) this type of microscopy is typically combined with the use of basic dyes. c) the image is formed only by reflected and refracted light rays. d) a and c
The correct statement about dark field microscopy is: a) this can be used to view live organisms; c) the image is formed only by reflected and refracted light rays.
Dark field microscopy is the technique where objects are observed under oblique illumination by creating a contrast of the specimens. The technique can be applied to observe live organisms and it does not require the use of staining dyes as well.
Light rays are the geometric representations indicating the path of the light. These always travel in straight lines. The direction of light can only be changed by phenomena like reflection or refraction.
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telomeres are found at the ends of linear chromosomes. these structures have two primary functions. one function is to prevent the shortening of the ends of chromosomes during replication. the reason they can do this is because the telomere repeat sequence can be extended by:
Telomere repeat sequence can be extended by telomerase enzyme.
How can be telomeres extended?For all kinds of telomeres activity, there is a specific enzyme. This enzyme is known as telomerase. This telomerase can extend the telomere by repeated reverse transcription of a short sequence. Telomerase is basically RNA-dependent DNA polymerase. So, according to its name, it can use RNA as a template to produce DNA. This enzyme adds complementary RNA bases to the 3' end of the DNA strand. When the 3' end of the lagging strand template is elongated completely, DNA polymerase can add nucleotides to the ends of the chromosomes.
So, telomere repeat sequence is extended by telomerase enzyme.
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