Answer:
Explanation:
The circulatory system, also called the vascular system or cardiovascular system. It consists of three important components such as heart or cardiovascular system, lungs or pulmonary system, vascular system such as arteries, veins and capillaries.
This system is responsible for the transport of gases, blood and nutrients to all the parts of the body. It helps in maintaining the homeostasis of the body by stabilizing the pH, body temperature and fighting the diseases. Also maintains the balance of hormones.
We know the planet can't support an ever-increasing human population. At some point humans will outstrip the resources available. Are we doomed?
A. Definitely
B. No. With foresight and planning, we can possibly reach a sustainable equilibrium before it is too late.
C. There's no way to know. We just have to do what we do and hope for the best.
D. No. Technology will keep expanding our resources to keep up with population growth, like has happened with agriculture so far.
E. Wealthy countries like the United States will be okay, but developing countries are doomed.
Answer:
A definitely
Explanation:
Us human are evil.
that's my honesty
Final answer:
Population growth and Earth's resources are at odds, with concerns over carrying capacity and sustainability. Technological and planning efforts can mitigate the situation, aiming for sustainable equilibrium and zero population growth in developed nations. Careful management of resources is essential to avoid a population catastrophe.
Explanation:
The question of whether an ever-increasing human population can be sustained on Earth revolves around notions of carrying capacity, resource depletion, and sustainability. The limits of growth debate considers whether societies can grow indefinitely or face a limit based on Earth's resources. With the current ecological footprint, some argue that we have already surpassed Earth's capacity to support our population, leading to environmental damage and extreme poverty. Nonetheless, the prospect of a sustainable equilibrium depends on human actions, including the use of technology, planning, and global cooperation to manage resources wisely.
Sustainability efforts and technological advancements in agriculture, energy, and water management are vital to expanding resources and reducing the ecological footprint. Nevertheless, environmental alterations, ranging from climate change to biodiversity loss, have resulted from technological interventions, casting uncertainty over the capacity for continued support of human populations without significant changes to consumption and production patterns.
Achieving zero population growth in some economically developed countries suggests that stabilizing populations is feasible. However, the disparities between developed and developing nations in reaching such a balance remain a critical challenge. The path to avoiding a population crash involves mindful stewardship of Earth's resources and equitable distribution to prevent drastic outcomes for humanity.
Where is sperm first produced? Where do the sperm cells mature?
Sperm are first produced in the seminiferous tubules inside the testes. They mature in the epididymis where they acquire motility and the ability to fertilize. They are released during ejaculation, travelling through the ductus deferens and exiting via the urethra.
Explanation:Sperm are first produced in the seminiferous tubules that are coiled inside the testes. The least mature cells, the spermatogonia, dwell along the basement membrane inside the tubule and undergo division to produce primary and secondary spermatocytes, and then spermatids. These spermatids finally mature into spermatozoa, or formed sperm, in a process known as spermatogenesis.
The sperm cells mature further in the epididymis, where they gain the ability to move and fertilize an oocyte. The mature sperm are stored in the epididymis until ejaculation. During ejaculation, sperm exit the epididymis through the ductus deferens, where secretions from the prostate and bulbourethral glands help form semen, assisting the sperm in their journey through the urethra and into the female reproductive tract.
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Beadle and Tatum's concept of the gene has been further refined to state which of the following most correct and current idea?
a. one gene - one enzyme
b. one gene - one polysaccharide
c. one gene - one metabolic block
d. one gene - one allele
Answer:
a. one gene - one enzyme
Explanation:
Genes are connected to enzymes was first suggested by Sir Archibald Garrod. Later on, Beadle and Tatum carried out genetic studies on Neurospora and confirmed Garrod's hypothesis.
The link between genes and enzymes was called “one gene-one enzyme hypothesis”.
But this hypothesis is not accurate and changed because some proteins are encoded by genes are not enzymes. Some genes do not encode a whole protein but a subunit of a protein. In general, one polypeptide (a chain of amino acids) encoded by one gene.
The genotype of F1 individuals in a tetrahybrid cross is AaBbCcDd. Assuming independent assortment of these four genes, what are the probabilities that F2 offspring will have the following genotypes?
(a) aabbccdd
(b) AaBbCcDd
(c) AABBCCDD
(d) AaBBccDd
(e) AaBBCCdd
Answer:
Explanation:
(a) aabbccdd : 0.4%
(b) AaBbCcDd : 6.3%
(c) AABBCCDD : 0.4%
(d) AaBBccDd : 1.6 %
(e) AaBBCCdd: 0.8 %
doing the tetrahybrid cross can be awfully difficult. You can always search for online sites that can help you with it.
Two short-haired cats mate and produce six short- haired and two long-haired kittens. What does this information suggest about how hair length is inherited?
Answer:
In the progeny, six kittens were short haired and two were long haired. The ratio of short to long haired kittens is 3:1 which is a classic monohybrid cross ratio. Here, short hair is inherited dominantly and long hair is inherited recessively. Both the parents are heterozygous for short hair trait (Ss). Cross between them:
Ss X Ss :
S s
S SS Ss
s Ss ss
Genotypically: 1 : 2 : 1
SS Ss ss
Phenotypically: 3 : 1 = 6 short and 2 long haired kittens
short hair long hair
Hence short hair is dominant over long hair in these cats.
Final answer:
Hair length in cats is inherited according to Mendelian genetics, with short hair being dominant and the observed offspring ratio suggesting both parent cats are heterozygous for the trait.
Explanation:
The mating of two short-haired cats resulting in both short-haired and long-haired kittens suggests that the trait for hair length in cats is inherited in a Mendelian fashion, with the allele for short hair (S) being dominant over the allele for long hair (s). Since both parents are short-haired but have produced long-haired offspring, it implies that each parent is heterozygous (Ss), carrying one allele for short hair and one for long hair. The distribution of short-haired to long-haired kittens (a roughly 3:1 ratio) fits the expected outcome of a Mendelian monohybrid cross, where both parents are heterozygous for a trait.
What causes ulcers? What prevents them?
Gastric ulcer is nothing more than an injury to the tissue lining the stomach. It may also be called peptic ulcer or stomach ulcer.
The most common cause of ulcer formation is the proliferation of a bacterium called Helicobacter pylori. There are other less common factors such as diet, overuse of drugs, smoking, stress and alcohol.
The best way to prevent an ulcer contraction is to maintain hygiene habits to prevent Helicobacter pylori infection. It is also good to avoid excessive consumption of alcohol, smoking and medications such as pain killers.
The light reaction of photosynthesis does not include
A) chemiosmosis
B) oxygen liberation
C) charge separation
D) electron transport
Answer:
The correct answer will be option-C.
Explanation:
Photosynthesis is a complex process which converts light energy into chemical energy which is used to form the glucose molecule. Photosynthesis occurs in two stages: light-dependent and light-independent reaction.
The light-dependent reaction is the reaction which takes place in the sunlight and converts light energy to chemical energy in ATP and NADPH molecules.
The light-dependent begins when photosystem absorbs light energy which causes the excitation of the electrons provided by chlorophyll molecule. The excited electrons get accepted by electron acceptor molecule and a chain of electron flow begins called electron transport chain.
This creates a scarcity of electron in photosystem which causes hydrolysis of the water molecule as a result oxygen gas is released. The electron flow leads to the synthesis of ATP molecules through chemiosmosis.
Thus, Option-C is the correct answer.
A particular virus with DNA as its genetic material has the following proportions of nucleotides: 20% A, 35% T, 25%G, and 20% C. How can you explain this result?
Answer:
Virus may be defined the acellular organism that contain DNA or RNA as their genetic material. Thee virus may contains double stranded or single stranded DNA or RNA molecule.
The DNA has composition of 20% A, 35% T, 25%G, and 20% C. The virus DNA does not follow Chargaff's rule in which the amount of thymine is not equal to the amount of adenine. The amount of guanine is not equal to the amount of cytosine. The DNA virus consist of single stranded DNA.
Complete the following statements using as many of the following terms as are appropriate: mitosis, meiosis I (first meiotic division), meiosis Il (second meiotic division), and none (not mitosis nor meiosis I nor meiosis Il). a. The spindle apparatus is present in cells undergoing_____ b. Chromosome replication occurs just prior to_____ c. The cells resulting from____ in a haploid cell have a ploidy of n. (d). The cells resulting from____ in a diploid cell have a ploidy of n. (e). Homologous chromosome pairing regularly occurs during_____ (f). Non-homologous chromosome pairing regularly occurs during_____ (g). Physical recombination leading to the production of recombinant progeny classes occurs during____ (h). Centromere division occurs during_____ (i). Non-sister chromatids are found in the same cell during
Mitosis is responsible for cell division, meiosis I reduces ploidy level, crossing over and chromosome recombination occur in meiosis I, and non-sister chromatids are found in the same cell during meiosis I.
Explanation:a. The spindle apparatus is present in cells undergoing mitosis.
b. Chromosome replication occurs just prior to meiosis I.
c. The cells resulting from meiosis I in a haploid cell have a ploidy of n. (d). The cells resulting from meiosis II in a diploid cell have a ploidy of n.
e. Homologous chromosome pairing regularly occurs during meiosis I.
f. Non-homologous chromosome pairing regularly occurs during meiosis II.
g. Physical recombination leading to the production of recombinant progeny classes occurs during meiosis I.
h. Centromere division occurs during meiosis II.
i. Non-sister chromatids are found in the same cell during meiosis I.
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What is a biogeographic realm? List eight of them. How do biogeographic realms indicate relatedness in terms of biodiversity at the global level?
Answer:
Biogeographic realms refer to the huge spaces or regions on the surface of the Earth within which the development of ecosystems takes place. The animal and plant species witnessed in a biogeographic realm share identical features all the way through.
The eight biogeographic realms are the afrotropical realm, Indomalayan realm, Antarctica realm, Neotropical realm, Nearctic realm, Palaearctic realm, Oceanian realm, and Australian realm.
The biodiversity signifies the variability between the living species in every possible manner. Each of the biogeographic realm exhibiting identical environmental conditions or identical mediators of modification has been found to comprise an identical kind of biota.
However, diversity can be found within it too. For example, the tropical moist rainforest found in any section of the globe will share identical procedures and vegetation, however, its specific structure will vary on the basis of the biogeographic realm in which it is witnessed.
Analogous adaptation to the similar kind of environmental conditions between the distinct species of the distinct biogeographic realm can be witnessed at a global level.
The reaction-center chlorophyll of photosystem I is known as P700 because
A) there are 700 chlorophyll molecules in the center
B) this pigment isbest at absorbing light with a wavelength of 700 nm.
C) there are 700 photosystem I components to each chloroplast.
D) it absorbs 700 photons per minute
Answer:
The correct answer will be option-B.
Explanation:
Photosystem of a plant is complex pigment-protein molecules which absorbs the light energy required for the formation of a glucose molecule.
Two types of Photosystem are present in the plants which are: P₆₈₀ and P₇₀₀. The 680 and 700 denote the wavelength of the light energy absorbed by the pigment of the chloroplast. The electrons get excited only at their absorbing wavelength.
Thus, Option-B is the correct answer.
The reaction-center chlorophyll of photosystem I, known as P700, is named for its ability to absorb light optimally at a wavelength of 700 nm.
Explanation:The reaction-center chlorophyll of photosystem I is known as P700 because this pigment is best at absorbing light with a wavelength of 700 nm. You can deduce this from the way reaction center chlorophylls in photosystems are named. For example, P680 reaction centers, found in photosystem II, are named for their peak light absorption at 680 nm.
Importantly, the naming does not reflect the number of chlorophyll molecules or photosystem components, nor does it relate to the number of photons absorbed per minute, but it is solely based on the wavelength of light that is most effectively absorbed by the pigment.
Glucose travels in the plasma or liquid part of
your blood butcholesterol (triglycerides) travel bound to protein
carriers in theblood. Based on their respective chemical
properties, explain thereason for this difference.
Answer:
Explanation:
Glucose is a sugar, highly soluble in water because it has lots of polar hydroxyl groups (-OH) which can form hydrogen-bonds with water molecules. These types of bonds are intermolecular forces which are present in other macromolecules like the DNA or proteins.
Cholesterol and triglycerids are lipids. These have long chains of hydrocarbons, which are non polar and therefore insoluble in water.
Blood is made of a solid and a liquid part. The solid part contains cells. The liquid part (plasma), is made of water, salts, and proteins. Glucose and cholesterol/triglycerids travel in the liquid part of the blood, in an aqueous environment. Because the lipids are not soluble, they need to travel with a carrier protein that keeps them protected from the surrounding water.
Briefly describe Wernicke and Broca aphasia. What is a main difference of these two classic types of aphasia and can be useful in the process of clinical differentiation. What symptoms can help to identify the localization of damage?
Answer:
Broca's area refers to a motor speech region, which assists in movements needed at the time of the production of speech. When an injury takes place in the frontal parts of the left hemisphere, it can give rise to various kinds of language issues. This section of the brain plays an essential role in putting words together to produce complete sentences. The injury to the left hemisphere is known as Broca's aphasia, also known as expressive aphasia.
Wernicke's aphasia also called receptive aphasia, posterior aphasia, or sensory aphasia is a kind of aphasia in which individual encounters with difficulty in understanding spoken and written language. Thus, the two kinds of aphasia are expressive aphasia in which one faces difficulty in conveying thoughts via writing and speech. The other is receptive aphasia, in which one finds difficulty in understanding the written or spoken language.
By analyzing the symptoms that whether the patient exhibits difficulty in understanding speech and using accurate words to express thoughts or the movements that are needed to generate speech, one can find the site of destruction.
What is ATP's importance in the cell? ATP stores energy in carbonyl groups. When a carbonyl group is removed, energy is released to be used in cellular processes. ATP contains a long hydrocarbon tail and is important in storing energy. ATP is an important component of cell membranes because it is nonpolar and hydrophobic. ATP can add phosphate groups, thereby releasing energy that can be used in cellular processes. ATP stores the potential to react with water, thereby removi
ATP is essential in a cell as it stores and transfers energy required for various cellular activities. Its energy is stored in high-energy phosphate bonds, which are broken to facilitate energy release. It does not contribute to the cell membrane structure due to its polar, hydrophilic characteristics.
Explanation:ATP, or Adenosine Triphosphate, plays a crucial role in the cell as it acts as a medium for energy storage and transfer. It is the main source of energy for most cellular processes. ATP doesn't store energy in carbonyl groups, rather it stores energy in the high-energy phosphate bonds. These bonds are broken to release the energy needed for various cellular activities.
ATP is not an important component of cell membranes, nor does it have a long hydrocarbon tail. It doesn't contribute to the structure of the cell membrane because it is polar and hydrophilic, unlike the major constituents of the cell membrane - phospholipids, which are both hydrophobic and hydrophilic.
The process of ATP releasing energy involves hydrolysis where a phosphate group is removed, allowing the stored energy to be used for various metabolic and physiological processes within the cell. It doesn't add phosphate groups but rather loses them in the process of energy release.
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ATP is the primary energy currency of the cell, storing energy in high-energy phosphate bonds and releasing it to power cellular processes. Cells produce ATP through cellular respiration, and it is used in various essential activities like metabolism and muscle contraction. ATP is continually recycled within the cell to maintain energy balance.
The Importance of ATP in Cellular Processes
Adenosine triphosphate (ATP) is often described as the energy currency of the cell. It is a molecule that stores and transports chemical energy within cells. ATP's energy is stored in its phosphate ester bonds, particularly the two high-energy phosphate anhydride linkages. When one of these bonds is broken, usually through the removal of a terminal phosphate group, energy is released. This energy is utilized in a variety of cellular processes, including metabolism, active transport, muscle contraction, and cell division.
Cells produce ATP during cellular respiration, a process which involves the oxidation of carbohydrates, proteins, and fats. The oxidative reactions that produce ATP occur in the cytoplasm and mitochondria of the cell. Once produced, ATP can be used immediately or stored for short periods until the energy is required for cellular reactions or for performing mechanical work, such as muscle contraction.
Phosphorylation is the process by which ATP transfers a phosphate group to another molecule. This process requires energy and is a key mechanism by which cells convert ATP's stored energy into a form that can do biological work, powering a vast array of endergonic reactions in the cell. ATP is continually recycled within the cell; it is constantly being made from ADP and inorganic phosphate and used up in cellular activities, maintaining the energy homeostasis of the cell.
Rods are light sensitive cells of the retina that provide information about color to the brain.
a. True
b. False
Answer:
The correct answer will be option-false.
Explanation:
The eye contains a layer of photoreceptor cells at the back of the eye called retina. The retina contains two types of photoreceptor cells called Cones and rods.
The rod cells contain only one types of pigment and are very sensitive to light and dark changes but cones contains three types of photoreceptors which are sensitive to red, blue and green color.
The cone cell sends signals to the brain about these colors where the brain perceives and produce an image.
Thus, option- false is the correct answer.
A double stranded base-paired structure formed by folding a single strand of DNA or RNA back upon itself.
a. mirrorlike palindrome
b. A-DNA
c. B-DNA
d. hairpin
Answer:
d. hairpin
Explanation:
A double-stranded base-paired structure formed by folding a single strand of DNA or RNA back upon itself like a hairpin. Base pairs are the unit of nitrogenous bases which are joined together by hydrogen bonds. They synthesize the double helix model which contribute the folded structure of both RNA and DNA. Sugar and phosphate is the backbone of DNA. DNA has four nitrogenous bases named adenine, thymine, guanine, and cytosine.
The anticodon of a particular tRNA molecule is
a. complementary to the corresponding mRNA codon.
b. complementary to the corresponding triplet in rRNA.
c. the part of tRNA that bonds to a specific amino acid.
d. catalytic, making the tRNA a ribozyme.
Answer:
The anticodon of a particular tRNA molecule is a. a complementary to the corresponding mRNA codon. Below, I let you an explanation of how DNA translation ocurrs as a complement to your study.
Explanation:
The translation of the genetic code is a process in which RNA becomes an amino acid junction to form a protein. This is a process which is divided into three parts: initiation, elongation and termination.
In the Initiation stage the ribosome binds with the mRNA and the first tRNA so that translation can begin.
Initiation :
For this process it is necessary to have:
• A ribosome (specialized organelle)
• An mRNA which carries the instructions
• A "start" tRNA that carries the first protein amino acid
When these three things come together, the initiation complex is formed, which will begin the formation of proteins. For this process it is necessary that the cell provides energy in the form of guanosine triphosphate (GTP )
Elongation occurs when the polypeptide chain increases in length.
In the ribosome there are several specialized places for each function. The first tRNA, which carries methionine, is located in the center of the ribosome space in a place called site P. Next to this site, a new codon is exposed, in another space and is called site A. Site A will be the location space for the next tRNA, whose codon is complementary to the codon that is exposed. This means that each tRNA is accompanied by auxiliary proteins, and only one tRNA that binds perfectly will be "released" at site A. To release the tRNA, a molecule that stores energy mentioned above, guanosine triphosphate (GTP) is used.
After the corresponding tRNA is located at site A, the formation of the peptide bond is given which is responsible for connecting one amino acid to another.
Termination occurs when a stop codon in the mRNA (UAA, UAG, or AGA) enters site A. Here release factors read the termination codons and are located at site P these release factors interfere with the function of the enzyme responsible for forming the peptide bonds then finally the tRNA chain is separated, and the newly dormant protein is released
The anticodon of a particular tRNA molecule is complementary to the corresponding mRNA codon. The correct option is A.
When protein synthesis is taking place, the anticodon of a tRNA molecule is a three-nucleotide sequence that is complementary to the matching codon on the mRNA molecule.
The correct translation of the genetic code is made possible by this complementary matching, which enables the tRNA to identify and attach to the mRNA codon through base pairing. The exact amino acid that will be incorporated into the expanding polypeptide chain during protein synthesis is determined by the anticodon.
Thus, the ideal selection is option A.
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Which of the following is not true of RNA processing?
a. Exons are cut out before mRNA leaves the nucleus.
b. Nucleotides may be added at both ends of the RNA.
c. Ribozymes may function in RNA splicing.
d. RNA splicing can be catalyzed by spliceosomes.
The correct answer is option d, as RNA splicing is indeed catalyzed by spliceosomes.
Explanation:d. RNA splicing can be catalyzed by spliceosomes.
In RNA processing, the process of removing introns and joining exons together is called RNA splicing. This process is facilitated by the presence of ribozymes, which are RNA molecules that catalyze chemical reactions. One type of ribozyme involved in RNA splicing is the spliceosome, a large and complex assembly of proteins and RNA.
Therefore, the correct answer is option d, as RNA splicing is indeed catalyzed by spliceosomes.
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The incorrect statement about RNA processing is that 'Exons are cut out before mRNA leaves the nucleus.', as it is actually the introns that are removed, not the exons. The correct answer is a.
The student has asked which statement is not true about RNA processing. The correct answer to this question is 'a. Exons are cut out before mRNA leaves the nucleus.' In fact, during RNA processing, it is the introns that are cut out while the exons are joined together. This process, known as splicing, is essential for converting the pre-mRNA transcript into a mature mRNA molecule that can be translated into protein.
The modifications that occur during RNA processing in eukaryotic cells include the addition of a 5' cap and a poly-A tail to the pre-mRNA, and the removal of introns by splicing which can be catalyzed by spliceosomes or ribozymes. Different splicing patterns can lead to the production of various mRNA transcripts from the same DNA sequence, a phenomenon known as alternative splicing.
Therefore, the statement that 'Exons are cut out...' is not correct since exons are the sections that remain in mRNA after the introns have been removed. RNA processing includes the removal of introns, addition of nucleotides at both ends, and splicing by spliceosomes or ribozymes.
Describe the steps in translation that require complementary base pairing.
Answer:
Translation is the synthesis of protein synthesis from RNA where genetic information encoded in mRNA, which is then translated into a sequence of amino acids present in a polypeptide chain. These are the steps in translocation:
1) Ribosomes bind to mRNA present in the cytoplasm and move with the molecule in a 5'-3' direction until it reaches a start codon AUG.
2) Anticodon present on tRNA molecule binds with appropriate opposite codon according to complementary base pairing. (translocation depends on complementary base pairing, e.g. AUG=UAC between codons present on mRNA and anticodons on tRNA)
3) Each tRNA molecule has specific amino acids, according to the genetic code.
4) Ribosomes catalyze the formation of peptides bonds with the help of condensation reaction between adjacent amino acids.
5) Ribosomes move with the mRNA molecule which is synthesizing a polypeptide chain until it reaches a stop codon.
6) At this stage, translation comes to stop and the polypeptide chain is released.
Dominance hierarchies
a. are found only in monogamous and solitary primates
b. likely give dominant males and females a reproductive advantage
c. are permanent and inflexible
d. do not result in dominant females having priority access to food
Answer:
The correct answer is option B. likely give dominant males and females a reproductive advantage .
Explanation:
Dominance hierarchy is a social hierarchy in which members of a group of animals interact with each other to form a ranking system or superiority and inferiority of the organism. In such social groups, members have to compete for access for the food and resources which are limited.
Mating is also decided on the basis of the dominance of males and females in such social groups. Dominant male-female have always advantage for mating in comparison to lower members in the ranking.
For instance, female baboon mated to a dominant male or high ranked male so she can get high rank as well for the time of period.
Thus, the correct answer is option B. likely give dominant males and females a reproductive advantage .
Describe the steps in transcription that require complementary base pairing.
Answer:
Explanation:
Transcription takes place in nucleus in the presence of the enzyme RNA polymerase.
During transcription, the code present in DNA gets transcribed into the code in mRNA. (messenger RNA)
RNA even though is a single stranded shows base pairing.
The pre-mRNA gets created from the DNA.
DNA has two strands, one of these strands acts as coding and another non coding strand.
The DNA shows base pairing with AGTC. [A-Adenine, G- Guanine, T-Thymine and C- Cytosine]
Whereas mRNA base pairing with AGUC. [ U- Uracil ]
Here in mRNA, instead of thymine, uracil gets paired.
According to base pairing of coding strand/sense strand of DNA, complementary bases pairs in 5'---->3' direction in mRNA.
The mRNA created looks exactly like the non-coding strand/sense strand of DNA except instead of thymine, uracil gets replaced.
The pre-RNA undergoes splicing, capping and tailing to form mature mRNA.
Final answer:
During transcription's initiation phase, RNA polymerase binds to a promoter, unwinds DNA, and catalyzes complementary base pairing between RNA nucleotides and DNA template, forming mRNA. Elongation continues this process, and termination occurs when specific base-pairing signals the end of transcription.
Explanation:
In transcription, the formation of the mRNA strand from a DNA template involves specific steps where complementary base pairing is essential. Initiating the process, RNA polymerase binds to a gene's promoter region during the initiation phase and unwinds the DNA helix, allowing one of the DNA strands to be 'read'. The new mRNA strand grows by the addition of RNA nucleotides that form hydrogen bonds with the complementary deoxyribonucleotides of the unwound DNA template strand. Here, the base cytosine (C) pairs with guanine (G), guanine (G) with cytosine (C), adenine (A) with uracil (U), and thymine (T) with adenine (A).
The elongation phase of transcription includes the continued addition of RNA nucleotides. Complementary base pairing ensures the correct sequence of nucleotides is added to the growing mRNA strand. The termination phase concludes transcription;
Complementary base pairs also play a role in the termination of transcription. Unique sequences in the DNA signal the end of the mRNA transcript, and following the base-pairing rules, these sequences can form structures such as hairpins that signal RNA polymerase to stop transcription.
The difference between gross primary productivity and net primary productiviry is determined by the respiration of primary producers.
a. True
b. False
Answer:
True
Explanation:
Gross primary productivity (GPP) of a system is defined as the rate by which the primary producers trap the solar radiation during the process of photosynthesis. The gross primary productivity is represented as total photosynthesis per unit area in a given time.
The net primary productivity (NPP) refers to the energy available to the plants for their growth after cellular respiration and is represented as plant growth per unit area in a given time.
Plants use part of the gross primary productivity in cellular respiration to produce the energy required to perform other vital functions. Hence, the energy consumed in cellular respiration differentiates the gross primary productivity and the net primary productivity.
NPP = GPP - Plant respiration
Net biomass productivity is the difference between gross productivity and respiration. It is influenced by factors like climate and soil nutrients. Forests tend to have high net biomass productivity while deserts have low productivity.
Explanation:Net biomass productivity is the difference between gross productivity (production of plant material by photosynthesis) and respiration. Net productivity is closely related to a number of environmental factors like climate, soils, and available nutrients. Net biomass production will be highest where there is an ample supply of moisture to meet the needs of plants. Biomass productivity is also high where soils are rich in nutrients and have a positive soil moisture balance. Forest, especially tropical forest have high net biomass productivity while deserts have low productivity.
The statement that the difference between gross primary productivity and net primary productivity is determined by the respiration of primary producers is true. Gross primary productivity (GPP) is the rate at which photosynthetic primary producers, such as plants, incorporate energy from the sun. However, not all of this energy remains within the plants because they must use a portion of it for their own metabolic processes, primarily through cellular respiration. The energy that remains after accounting for this respiration is known as the net primary productivity (NPP). It is the energy that is actually available to primary consumers in an ecosystem. The NPP can be influenced by various environmental factors, such as climate, availability of nutrients, and moisture levels, leading to variations in the productivity of different ecosystems, like tropical forests having high NPP while deserts have relatively low NPP.
Cells of plants and animals have _____________.
a. central vacuole and mitochondria
b. cell membrane and cell wall
c. chromosomes and chloroplasts
d. nucleus and DNA
Answer:
cell membrane and cell wall
Removal of one of a pair of endocrine glands often results in atrophy of the other gland.
a. True
b. False
Answer:
False
Explanation:
When one of the glands is removed, the other continues to perform its function because they are independent entities that can continue to secrete hormones. This happens with the adrenal glands for example.
What are the four main human activities that cause a loss of biodiversity?
a. Preservation, habitat destruction, overharvesting, and use of chemical pollutants
b. Habitat destruction, invasive species displacement, use of chemical pollutants, and overharvesting
c. Overharvesting, conservation, use of chemical pollutants, and invasive species displacement
d. conservation, preservation, use of chemical pollutants, and overharvesting
e. Habitat destruction, overharvesting, conservation, and use of chemical pollutants
Answer:
The correct answer will be option-B.
Explanation:
Biodiversity represents the variety of the biological organism-form microorganism to plant and animals in any particular habitat.
The biodiversity loss is a serious problem in the modern world which is caused by the growth rate of humans and resource exploitation.
Humans depend on the natural resources for their use due to which they modify the natural area leading to the habitat loss. They over-harvest the natural resources like aquatic organisms mainly fishery industry.
The growth rate of humans has forced us, humans, to increase productivity in every area sue to which humans use harmful chemicals like pesticides and insecticides which directly affect biodiversity. it leads to algal bloom and eutrophication of small water bodies.
The introduction of exotic species to any area results in the displacement of the invasive species of the area which directly affects the natural habitat.
Thus, Option-B is the correct answer.
Answer:
The Correct answer is B
Explanation:
The loss of biodiversity can be focused on the activities of Human beings on the world's ecosystem which is the major cause of its loss.Overexploitation of natural resources is the human activities which are the major cause of biodiversity loss.Population growth and overconsumption is one of the major cause of Human activity which is responsible for the loss of Biodiversity.If you came into contact with Vibrio, what defense do you have to keep it from even getting to your intestines?
A. Your skin is an effective barrier against bacteria you come in contact with.
B. Antimicrobial enzymes in saliva
C. Acid in the stomach
D. Mucous membranes in the digestive and respiratory tract
E. All of the above
Answer:
The correct answer is E. All of the above
Explanation:
The body contains different physical and chemical barriers to protect itself from the invasion of any pathogen. These barriers act as the first line of defense to the body and include skin, mucous membrane, acids, and antimicrobial enzymes.
Skin acts as a mechanical barrier to microbes and does not allow any pathogen to invade through it until it gets punctured.
Saliva contains antimicrobial enzymes like lysozyme which kills bacteria by destroying their cell wall. Hydrochloric acid released in the stomach is highly efficient to kill pathogens coming with food.
Mucous membranes in the digestive and respiratory tract contain WBCs, antimicrobial enzymes and proteins which kills the invaded pathogen like Vibrio.
Although meat lacks cellwalls, repeated freezing and thawing
produces the bad taste offreezer burn. What is the main organelle
involved in thisautodigestion?
Answer:
Lysosome
Explanation:
Freezer burn occurs due to the sublimation of ice in unprotected meat rich in muscles during long-frozen storage. It appears after thawing. The ice crystals rupture the lysosomes which in turn contain hydrolyzing enzymes.
Leakage of the hydrolytic lysosomal enzyme causes freezer burn and affects the appearance of the frozen meat. The hydrolytic enzymes of lysosomes partially digest the cells which in turn impart bad flavor to the stored food.
Which group is incorrectly paired with its description?
a. diatoms—important producers in aquatic communities
b. red algae—eukaryotes that acquired plastids by secondary endosymbiosis
c. apicomplexans—unicellular parasites with intricate life cycles
d. diplomonads—unicellular eukaryotes with modified mitochondria
Answer:
b. red algae—eukaryotes that acquired plastids by secondary endosymbiosis
Explanation:
Red algae did not acquire plastids by secondary endosymbiosis and thus, option b is an incorrect pair. Red algae are eukaryotes that are red in the color not because they acquired plastids y endosymbiosis but because they produce the enzyme phycoerythrin and phycocyanin which masks the other pigments present in it.Secondary endosymbiosis is a process by which the product of primary endosymbiosis is engulfed by another organism. Such type of process never occurred in case of red algae.Plastids that are surrounded by more than two membranes are evidence of
a. evolution from mitochondria.
b. fusion of plastids.
c. origin of the plastids from archaea.
d. secondary endosymbiosis.
Answer:
d. secondary endosymbiosis.
Explanation:
When a living cell acquires another organism that eventually becomes a part of this cell, this process is known as primary endosymbiosis.When an organism that has already undergone primary endosymbiosis engulfs another eukaryotic organism then this process is known as secondary endosymbiosis. Secondary endosymbiosis has been known to occur in plastids because of which they are surrounded by two membranes. This bilayer is present because one of the layers is the original outer membrane of the organism and the other membrane is that of the organism that has been engulfed.Why would a geneticist study a yeast cell or a fruit fly or a mouse in order to understand human genes and human biology?
Answer:
Due to common origin and similarity of genes.
Explanation:
Fruit fly and yeasts are common model organisms that are used by scientists to understand universal biochemical pathways.The universal biochemical pathways exist across different organisms because they share a common origin and have similar genes. The existence of similar genes helps the scientists to manipulate these model organisms such as yeast and fruit fly in the laboratory to understand human genes and human biology as it is ethically prohibited to perform experiments on humans, however, the same can be done on the mouse, fruit fly and yeast cell. Humans share 44 % of their genes with the fruit fly, 26% with yeast cell and 92% with a mouse.Final answer:
Geneticists study model organisms like yeast cells, fruit flies, and mice because they share significant genetic and biological characteristics with humans, making them practical and efficient for genetics research. These organisms facilitate the understanding of human genes and can be easily modified and cultured, allowing for more rapid scientific progress.
Explanation:
A geneticist would study organisms like yeast, fruit flies, and mice to understand human genes and biology because these organisms, known as model organisms, share many genetic and biological similarities with humans. Fundamentally, yeast cells (Saccharomyces cerevisiae) as eukaryotic organisms, produce and modify proteins in a way comparable to human cells, making them valuable for recombinant DNA technology experiments. Similarly, the fruit fly (Drosophila melanogaster) and the house mouse (Mus musculus) have been used extensively in genetic research because they have well-sequenced genomes and exhibit biological processes analogous to those in humans, such as metabolizing alcohol.
Fruit flies are particularly important because they are able to metabolize alcohol like humans, providing insights into genes affecting sensitivity to alcohol. This research holds the promise of understanding and potentially addressing variations in alcohol sensitivity in humans. Additionally, model organisms are generally easier to study due to their simpler structure, shorter generation times, and the ease with which they can be genetically modified.