Answer:
True
Explanation:
The net secondary productivity refers to the net amount of energy available to produce biomass at the consumer level. The energy available in the plant tissues after cellular respiration represents the net primary productivity. The net primary productivity represents the rate of incorporation of organic matter into the plant tissues. Hence, net primary productivity is the source of energy and organic matter for the net secondary productivity.
A part of the net primary productivity consumed by a herbivore is used in cellular respiration and other processes and the rest becomes available for biomass accumulation.
Due to the consumption of the part of the net primary productivity for vital processes at the consumer level, the amount of energy available for biomass accumulation, the net secondary productivity, is always less than the NPP.
what is the main problem with comparing the tree of life with the fossil record?
Answer:
Darwin gave the concept in evolution of species.
Explanation:
As we know the tree of life is quite massive and comparing it needs to be understood well in terms of fossils that were once hidden inside the layers of earth rock masses. The tree is phylogenetic representing the unique ancestral history of every creature. Analyzing their morphological, behavioral and habitats are mostly evaluated in the tree of life One major challenge is to find the roots of life for the evolutionists. Finding out the nature of the last common ancestor. Some theories suggest that the same ancestor has the same common history of origin may lead to confusion of evolutionist as acing them becomes difficult.A young couple went to see a genetic counselor because each had a sibling affected with cystic fibrosis. (Cystic fibrosis is a recessive disease, and neither member of the couple nor any of their four parents is affected.) a. What is the probability that the female of this couple is a carrier? b. What are the chances that their child will be affected with cystic fibrosis? c. What is the probability that their child will be a carrier of the cystic fibrosis mutation?
Answer:
a) The correct answer is 1/2 or 0.5
Cystic fibrosis is a recessive disorder and her sibling has a disease but none of the parents had it. Thus, each of the parents must be the carrier of the disease, that is, both of them must be heterzygous.
So, if we cross Cc x Cc, it results in the genotype ratio of 1 (CC) : 2 (Cc) : 1 (cc)
Thus, 2 out of 4 would be the carrier of the disease.
b) 1/16
The probability of female to the carrier is 1/2
Same is the case with male partner due to the probability that he would be the carrier is 1/2
If both are carrier then, there is only 1/4 chances that the offspring will have the disease (as per cross shown above).
Now, the probability that the offspring will have the disease = product of all the above probabilities. (The probability of occurrence of two independent events is equal to the product of their individual probabilities).
So, [tex]\frac{1}{2}x\frac{1}{2}x\frac{1}{4}[/tex] = [tex]\frac{1}{16}[/tex]
c) 1/8
The probability of female to be the carrier is 1/2
The probability male to be the carrier is 1/2
If both are carrier then, there is only 2/4 chances that the offspring will be the carrier of the disease (as per cross shown above).
Now, the probability that the offspring will be the carrier = product of all the above probabilities. (The probability of occurrence of two independent events is equal to the product of their individual probabilities).
[tex]\frac{1}{2}x\frac{1}{2}x\frac{2}{4}[/tex] = [tex]\frac{1}{8}[/tex]
Cystic fibrosis is a recessive disease requiring two copies of the mutant gene. The female in the couple is guaranteed to be a carrier since both her siblings are affected. The chances of their child having cystic fibrosis is 25%, while the chances of the child being a carrier is 50%.
Explanation:Cystic fibrosis is a recessive disease that requires an individual to inherit two copies of the mutant gene in order to develop the disease. In this case, both members of the young couple have siblings affected with cystic fibrosis, indicating that they are carriers of the mutant gene.
a. The probability that the female of this couple is a carrier is 100%, as both her siblings are affected with cystic fibrosis.
b. The chances that their child will be affected with cystic fibrosis is 25%, as shown by the Punnett square.
c. The probability that their child will be a carrier of the cystic fibrosis mutation is 50%, as 50% of the normal children will carry the gene without any symptoms of the disease.
A change in DNA resulting in an incorrect protein is the problem in sickle cell disease. Is this normally the problem in genetic diseases?
Answer:
Sickle cell disease in an autosomal recessive inherited disease which is caused by the mutation in the HBB (hemoglobin-β gene) gene present on the chromosome no. 11. In sickle cell, the red blood cells become sickle shape due to the abnormal shape of hemoglobin present in it.
These sickle cells are known to form a blockage in the blood vessels thereby causing damage to the vital organs. Human spleen constantly destroys sickle cells because they get trapped in it which causes a disease called sickle cell anemia.
Sickle cell anemia is normally the problem in genetic disease which is inherited from the parents to children. When both the DNA strand has a mutation in their HBB gene then only this disease will affect the individual.
Part A - Processes that determine heredity and contribute to genetic variation
Meiosis guarantees that in a sexual life cycle, offspring will inherit one complete set of chromosomes (and their associated genes and traits) from each parent. The transmission of traits from parents to offspring is called heredity.
Another important aspect of meiosis and the sexual life cycle is the role these processes play in contributing to genetic variation. Although offspring often resemble their parents, they are genetically different from both of their parents and from one another. The degree of variation may be tremendous.
The following processes are associated with meiosis and the sexual life cycle:
DNA replication before meiosis
crossing over
chromosome alignment in metaphase I and separation in anaphase I
chromosome alignment in metaphase II and separation in anaphase II
fertilization
Sort each process into the appropriate bin according to whether it contributes to heredity only, genetic variation only, or both.
-dna replication(assume no errors), -crossing over, -metaphase 1 -> anaphase 1, -metaphase 2 -> anaphase2, -fertilization
hereditary only:
genetic variation only:
both:
DNA replication contributes to heredity only, while crossing over, the alignment and separation of chromosomes in metaphase and anaphase I and II, and fertilization contribute to both heredity and genetic variation. These processes ensure a complete set of genes is inherited while also introducing genetic diversity.
Explanation:The process of heredity and genetic variation are guaranteed through DNA replication, crossing over, and the stages of meiosis including metaphase to anaphase I and II and the process of fertilization. In terms of DNA replication (assuming no errors), this contributes to heredity only as it enables a complete set of chromosomes to be passed down from the parent to the offspring. Crossing over, or the process of chromosomes exchanging segments during meiosis, contributes to both heredity and genetic variation as it ensures genes are transmitted and also adds variation through the reshuffling. The alignment of chromosomes in metaphase I and II and their separation in anaphase I and II contributes to both heredity and genetic variation as these stages ensure accurate division and distribution of genetic material and add variation through independent assortment. Lastly, fertilization, the process in which the egg and sperm unite their genetic material also contributes to both heredity and genetic variation, ensuring offspring inherits a complete set of genes from each parent and introducing variation through the random selection of each parent's genes.
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What is the role of the gizzard in bird digestion?
a. to store food for easy means of regurgitation to offspring
b. to chemically digest food
c. to store gastroliths that physically grind up food
d. to produce saliva to start the digestive process
The correct answer is C. To store gastroliths that physically grind up food.
Explanation
The gizzards, are a special part of the digestive system of some animals such as birds, fish, and reptiles whose main function is to crush the food that the animal ingests, for this task, the gizzards contain in their interior gastroliths, a kind of polished stones, that grinds the food that the animal eats. The gizzards represent an important part for these animals because many of them do not have teeth to crush their food and feed on it. So, the correct answer is C. To store gastroliths that physically grind up food.
All hormones are made wither from cholesterol or amino acids
a. True
b. False
Answer:
True
Explanation:
There are two type of hormones:
- Steroids, which are synthesized by chemichally modifying cholesterol
- Peptidic hormones, which are proteins, and as such, are made with aminoacids.
the time when life began at what era Cenozoic Era c. Mesozoic Era b. Paleozoic Era d. Cretaceous Period
Answer:
cretaceous period
Explanation:
the abiogenesis started in -4100 millions years ago.
source: curtis. biology 8th edition.
The life began during the time of Paleozoic Era.
Explanation:The Phanerozoic Eon is classified as three era namely:
The Paleozoic era or era of ancient life The Mesozoic era or era of middle life The Cenozoic era or era of new lifeThe initiation of life was seen during Paleozoic era. It began 542 million years back with the development of complex living things and finished 251 million years prior with the biggest mass elimination the world has ever experienced. It is the most seasoned and longest period of Phanerozoic Eon.
Know the difference between lipid soluble and water soluble hormones and how they elicit their effects on target cells.
Answer:
Water soluble hormone binds to the membrane bound receptors whereas lipid soluble hormones bind to the internal/intracellular receptors.
Explanation:
Hormones are called regulators because they can either stimulate or inhibit the target cell's activity.
They perform their action by binding to specific protein on target tissue called hormone receptors. Each receptor is specific for a particular hormone. The hormone-receptor complex bring about the biochemical changes in the target cell.
Hydrophillic or water soluble hormones interact with the membrane bound receptors. They result in the generation of secondary messengers such as cyclic AMP. Secondary messengers bring about the cascading action amplifying the final effect. That is why even a very small quantity of hormone is sufficient for a powerful cascading effect.
Lipid soluble hormones can diffuse through the plasma membrane and thus they bind to the intracellular receptors. The hormone-internal receptor complex enters the mucleus and regulates gene expression. Example: steroid hormones and thyroid hormones.
Lipid-soluble hormones can cross the cell membrane and directly influence gene expression, while water-soluble hormones bind to receptors on the cell membrane and trigger intracellular signaling pathways.
Explanation:Lipid-soluble hormones, such as steroid hormones, can pass through the cell membrane and bind to receptors in the cytoplasm or nucleus of target cells. Once inside the cell, they directly influence gene expression and protein synthesis, leading to changes in cell function.
Water-soluble hormones, such as peptide hormones, cannot pass through the cell membrane. Instead, they bind to receptors on the cell membrane surface and trigger intracellular signaling pathways, which ultimately result in the desired cellular response.
Overall, the main difference between lipid-soluble and water-soluble hormones is their ability to cross the cell membrane and where their receptors are located.
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he continuity of life is based on heritable information in the form of DNA. In a short essay (100–150 words), explain how the passage of genes from parents to offspring, in the form of particular alleles, ensures perpetuation of parental traits in offspring and, at the same time, genetic variation among offspring. Use genetic terms in your explanation.
Answer:
The organisms use DNA as the genetic (contains code of life) as well as heredity (transferred to progeny) material.
DNA is packaged into a highly condensed structure called chromosome which gets passed on to progeny through male and female gametes. The formation of the gametes involves meiosis which introduces recombination of the sequence of the DNA.
The chromosomes contain a sequence of DNA called genes which codes for a particular trait of organisms. These genes control a trait when they receive the complementary form of the gene from another chromosome.
When the gametes fuse then both the gametes contribute half of their chromosomes and make a complete set of chromosomes. Thus, the continuity of life is controlled by heredity material.
Continuity of life is ensured by parents passing genes, in the form of alleles, to their OFfspring. This process, driven by meiosis, ensures both perpetuation and genetic variation in offspring. This variation allows traits to evolve over time while maintaining species continuity.
Explanation:Continuity of life is fundamentally driven by the heritable transmission of DNA from parents to offspring. Parents pass on genes, which are organized in DNA and carry information specifying particular traits. The specific form of a gene, termed an allele, can result in differing forms of a trait. A parent with two different alleles for a trait can pass either allele to their offspring, ensuring both perpetuation of their traits and genetic variation.
During reproduction, a process called meiosis takes place in which parent cells divide to create sex cells, each containing a unique combination of alleles. This creates genetic variance and providing the raw material for evolution. Offspring receiving different combinations of alleles express traits that may appear to be a blend of parental traits, explaining how genetic material is passed down while still creating unique individuals.
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Which (if any) of the following statement regarding smallpox is not correct? if all of the statements are correct, choose the final answer.
a. the vaccine is made from live vaccinia virus
b. the disease is spread through respiratory droplets
c. smallpox has been eradicated worldwide.
d. the vaccine may revert to pathogenicity causing smallpox
e. all of the above statement regarding smallpox are correct
Answer:
The correct answers are e. "all of the above statement regarding smallpox are correct".
Explanation:
Smallpox vaccination is one of the most clear examples of the benefits of performing a global vaccination program, because smallpox has been officially eradicated worldwide in 1980. However, some precautions regarding this disease should be taken, as is a very pathogenic diseases that is spread through respiratory droplets. The smallpox vaccine contains live vaccinia virus and it may revert to pathogenicity, therefore its application should be performed by an expert to assure that the virus does not affect the patient.
What is a niche?
a. The particular set of resources a species uses
b. A mating system in which one male mates with several females
c. An example of population cycling
d. An evolutionary arms race
e. A plant structure containing many flowers
Answer:
a. The particular set of resources a species uses
Explanation:
A niche is described as the interaction of an individual with its environment. It is a functional position of an individual. The niche includes how an organism lives, its behavior and abiotic factors such as light, temperature, climate etc.The ecological niche is a multidimensional thought which includes the role of an individual like predation, mutualism, parasitism, competition etc. An example of niche; A bird lives on a tree and eat the fruits.
Cooking food adequately to kill microbes will prevent all food-borne illness.
a. True
b. False
Answer:
A. True
Explanation:
Cooking, not just heating up, but adequately cooking will help to kill a lot of microorganisms present in food. The majority of the microbes present in our food are mesophilic organisms, this means they grow best in temperatures between 68 and 113 °F, not too hot and not too cold. The only way to ensure these microorganisms are killed and prevent food-borne illness is to apply the correct amount of heat, more than 120 °F.
If the rice already had the genes that could make vitamin A, why did scientists use genes from other organisms?
A. The rice genes didn't make the right type of vitamin A.
B. It's easier to introduce genes from one species into another than from just one species.
C. Scientists could have just "turned on" the rice genes, but they wouldn't have learned anything from that process.
D. It's easy to extract genes from bacteria.
E. The scientists didn't know how to "turn on" the genes in the rice.
Answer:
A. The rice genes didn't make the right type of vitamin A.
Explanation:
Regular white rice does not have the gene to produce beta carotene. The human body converts the beta carotene into vitamin A.
To increase the nutritional value of rice, the gene for beta carotene from daffodil flowers was inserted into the cells of endosperm of rice.
This allowed these cells of the genetically engineered rice varieties to produce beta carotene. Production of beta carotene imparted golden color to the rice grain and hence, the name.
Which of the following statements best distingueshes hypothesis from theories in science?
a. Theories are hypotheses that have been proved.
b. Hypothesees are guesses; theories are correct answers.
c. Hypotheses usually are relatively narrow in scope; theories have broad explanatory power.
d. Theories are proved true; hypotheses are often contradicted by experimental results.
Answer: c. Hypotheses usually are relatively narrow in scope; theories have broad explanatory power.
Explanation:
In scientific decipline, the hypothesis is a tentative statement which is produced by the method of prediction and assumption based on direct observation of the natural phenomena or event. It can be tested by using the experimental methodology.
Theory is a explaination for the cause of natural event or phenomena. This is based on the evidences obtained after experimental trials. A hypothesis can be used for generation of theory. A theory is more explanatory approach because of the details and evidences than hypothesis. Hence, c is the correct option.
Each year, pine forests suffer large losses due to pine beetle infestation. These beetles carry a fungus that infects and kills the tree. Which, if any, of the following terms is not an accurate term for the role of the beetle?
a. pathogen
b. reservoir
c. vector
d. host
e. all of the above accurately describe the role of the beetle
Answer:
a. Pathogen
Explanation:
A pathogen organism is the main cause of disease in another organism. In this example, beetles just carry the fungus, which is the real cause of the infection in the pines. So, beetles are vectors of the fungus. They also can be called "Reservoirs" or "hosts", and the fungus is the pathogen that produces the pine’s death.
What is the main function of schlerenchyma tissues?
Answer:
Functions of the schlerenchyma tissues are as follows:
The schlerenchyma tissue supports the hard woody plants.
These tissue makes the plant hard and present at the bark of tree.
These tissue consists of lignin chemical that makes support the plant even after it is dead.
The elongation in plant is ceased by the schlerenchyma tissue.
This tissue also strengthen the plant.
Fabrics are produced from this tissue and contribute to the country economics as well.
Symptoms associated with which of the following diseases are due to production of an EXOtoxin that affects the nervous system (brain, spinal cord, nerves, etc.)?
a. polio
b. botulism
c. rabies
d. variant Creutzfeldt-Jakob disease (vCJD)
e. the symptoms of all of these diseases are due to neurotoxin production
Answer:
B
Explanation:
Botulism is a classical example of a exotoxin-mediated disease.
When C. Botulism grows in food, for example, and you eat it, it is the toxins that were produced that gives you the disease, not the bacteria per se.
A very characteristic presentation of this is infants that contract botulism from the soil (were the toxins are, but not the bacteria). Infants are much more susceptible to botulism because adults GI tract is mature enough to protect from the toxins, but infants usually cannot.
Indicate the role of each of the following in DNA replication: (a) topoisomerase, (b) helicase, (c) primase, and (d)ligase.
Answer:
(a) topoisomerase: is a type of enzyme that helps DNA to wind or unwind to help other enzymes while replicating because DNA becomes overwound ahead of a replication fork.
(b) helicase: helps the DNA to open up. It separates each strand and creates a replication bubble.
(c) primase: this enzyme will synthesize a short DNA fragment known as primer for the polymerase to start copying, the primer is like a signal for the polymerase to know which part it should start to copy.
(d)ligase: after replication happens this enzyme closes back the replication bubble and puts back together DNA like it was.
Final answer:
Topoisomerase relieves supercoiling tension in DNA during replication. Helicase separates DNA strands to allow replication. Primase synthesizes RNA primers needed for DNA polymerase, and DNA Ligase joins Okazaki fragments on the lagging strand.
Explanation:
Roles of Enzymes in DNA Replication
Topoisomerase plays a pivotal role by alleviating the tension in the DNA molecule that results from unwinding during replication. This is accomplished by causing transient breaks in the DNA strands and allowing the DNA helix to untwist, thereby preventing the over-winding or supercoiling ahead of the replication fork.
Helicase is crucial for separating the two DNA strands at the origin of replication, creating the replication fork that allows the replication machinery to access the single-stranded DNA.
Primase synthesizes a short RNA primer which is necessary for DNA polymerase to initiate the synthesis of the new DNA strand. Since DNA polymerases require a 3'-OH group to attach new nucleotides, a primer is essential for starting the replication process.
DNA Ligase is the enzyme responsible for joining Okazaki fragments by sealing the nicks in the sugar-phosphate backbone of the lagging strand, thus creating a continuous DNA strand.
Protozoans are the only organisms that can convert nitrogen from the air into chemical compounds that plants can use.
a. True
b. False
Answer: False
Explanation:
Protozoans are not the organism that fix nitrogen for the plants. The organism that fix nitrogen to convert it into a form which can be used by plants are known as diazotrophs.
These are bacteria and archae that fix nitrogen gas found in the atmosphere into more usable form such as ammonia.
These organism can grow without any external source of fixed nitrogen. Example: Rhizobia and azospirillium.
Draw the structure of an amino acid and a dipeptide.
Answer:
Amino acids are molecules with an amino group (-NH2), a carboxylic acid group (-COOH) and a variable group (X) that gives origin to around 20 different kinds of amino acids, you can see how the structure of an amino acid looks in the image I added.
A dipeptide is a molecule derived from two amino acids, as you can see in the image they form a bond between the amine group of one amino acid and the carboxylic acid group of the other one, forming a bond we call peptide bond, this reaction also produces a molecule of water.
Treatment levels that produce circulating levels in excess of natural or optimal levels are termed _____________
Answer:
Pharmacological doses
Explanation:
In our bodies the hormones and other regulators that are present usually operate in small quantities that range from pico to microgram/ml of blood and this level of hormone and other regulators is referred to as the physiological level.when treatments are given then it may lead to the production of these hormones or regulators that may exceed the physiological levels, and the levels may increase up to milligram range. Such treatments levels that lead to the excess production fo circulating levels that surpass the natural or optimal levels are termed as pharmacological doses.Approximately 16% of this alien genome is comprised of nucleotides containing C, and 22% is comprised of nucleotides containing Y. Given this information, calculate the percentage of the alien genome that is comprised of nucleotides containing G, T, A, and X. (a) _____% of the alien genome is comprised of G. (b) _____% of the alien genome is comprised of T. (c) _____% of the alien genome is comprised of A. (d) _____% of the alien genome is comprised of X.
Answer:
(a) 16 % of the alien genome is comprised of G.
(b) 17% of the alien genome is comprised of T.
(c) 17% of the alien genome is comprised of A.
(d) 22 % of the alien genome is comprised of X.
Explanation:
Assuming the alien follows Chargaff's rules which states that DNA from any cell of any organisms should have a 1:1 ratio (base Pair Rule) of pyrimidine and purine bases.
So if:
16% contains C ; 16 % pairs with G = 32% C-G pairing.
22% contains Y ; 22 % pairs with X = 44% X-Y pairing.
44% G-C + 32% X-Y = 76%
100%-76% = 34% the remaining should be split between T and A which is 17% each one.
Using Chargaff's Rule, 16% of the alien genome is comprised of G, and 22% is comprised of T. Percentages for A and X cannot be determined without additional information.
Explanation:Given that 16% of the alien genome is comprised of nucleotides containing C, and 22% is comprised of nucleotides containing Y, we can calculate the percentages of the remaining nucleotides by applying Chargaff's Rule, which states that DNA is a double helix that is held together by base pairs: A pairs with T, and G pairs with C. This means that the percentage of nucleotides containing G will be equal to that of C, and T will complement Y assuming that Y pairs with T in this alien genome, as A pairs with T in Earth organisms.
(a) Since 16% of the alien genome is comprised of C, then 16% of the alien genome is also comprised of G, as G pairs with C.
(b) If 22% is comprised of Y, and assuming Y pairs with T, then 22% of the alien genome is comprised of T.
(c) To find the percentage of A, we would need additional information since the question doesn't provide a direct pairing percentage. Given no other information, the percentage of A remains undetermined in this hypothetical situation.
(d) Without additional information about what X pairs with, we cannot accurately determine the percentage of X in the alien genome. If X pairs with an unknown or non-standard base or does not directly pair with one of the given nucleotides, we would not be able to apply Chargaff's Rule.
How many chromosomes will be in a normal human nucleus at the end of meiosis? a. 23 b. 46 c. 69 d. 92 e. none of the above is correct
Answer:
In human haploid cells there are 23 chromosomes.
In general, the Earth's climate became cooler throughout the course of the Cenozoic which greatly influenced the evolution of mammal's during this time period. Which of these is not a correct statement about this cooling event?
a. the Antarctic and Arctic ice sheet both formed during the end of the Miocene
b. falling carbon dioxide levels lead to a reverse greenhosue effect
c. water locked in ice contributes to decreased sea levels
d. ocean circulation patterns are affected by global cooing
e. the closing of the isthmus of Panama is a result of the drop in global temperature
Answer:
d. ocean circulation patterns are affected by global cooling
Explanation:
According to current studies, during glacial periods the change of ocean circulation and the increase of its productivity contributed to the reduction of atmospheric CO2 levels. As a result, this reduction influenced the cooling of the poles and the expansion of the Antarctic ice sheets in the Cenozoic period. Therefore the change in ocean circulation influences the cooling of the earth.
Why is it necessary to have a primer on each side of the DNA segment to be amplified?
Final answer:
Primers are essential in PCR as they provide a starting point for DNA polymerase to begin synthesis. A primer on each side of the desired segment ensures that only the specific DNA region is exponentially amplified through subsequent PCR cycles.
Explanation:
Importance of Primers in PCR Amplification
To understand why a primer is necessary on each side of the DNA segment to be amplified, it is important to grasp the fundamentals of the Polymerase Chain Reaction (PCR) process. Primers are short synthetic single-stranded DNA molecules that are reverse complementary to each of the two strands of the target DNA at their 3' ends. This means that the top primer anneals against the bottom DNA strand and the bottom primer anneals against the top DNA strand, essentially flanking the area to be replicated.
In the first cycle of PCR, the primers serve as an anchor for DNA polymerase, which can only add nucleotides to a pre-existing 3'-OH group provided by primers. Without primers, there would be no DNA synthesis as DNA polymerase requires a primer from which to extend the DNA strand. As a result, during the initial PCR cycle, two DNA fragments are produced: one that starts at the beginning of the desired sequence, and another that ends with the desired sequence, both extending beyond the DNA of interest.
The necessity of having a primer on each side is to ensure that in subsequent cycles of PCR, the area between the primers is selectively amplified. Each additional cycle further replicates the desired segment, ultimately leading to exponential amplification of the specific DNA region of interest.
Humans often think of themselves as unique, but in reality there are only a few distinguishing features. Which of these is unique to humans as compared to other mammals?
a. Eccrine glands for thermoregulation
b. Red blood cells that lack nuclei
c. Messner's corpuscles for sensing pressure
d. A fully erect posture associated with bipedalism
Answer:
b. Red blood cells that lack nuclei
d. A fully erect posture associated with bipedalism
Explanation:
Eccrine glands can be found on horses, you may have seen horses sweeting. The pressure sensors can be found in other apes too. Fully erect posture is a characteristic of humans, other apes or monkeys may walk sometime like this, but their main locomotion is in 4 extremities. Non nucleated is a characteristic that gives an advantage because more oxygen can be carried inside red blood cells making respiration more efficient.
Proteins encoded by the ____ genes turn off or decrease the rate of cell division.
A. proto-oncogenes
B. DNA repair
C. tumor suppressor
D. DNA replication genes
E. oncogenes
Tumor suppressor genes produce proteins that control cell division. If these genes are mutated or lost, cell division may become uncontrolled, leading to the formation of tumors. Therefore, the correct answer is C, tumor suppressor genes.
Explanation:Proteins encoded by the tumor suppressor genes decrease the rate of cell division. These genes produce proteins that maintain the regulation of the cell cycle and prevent the cells from dividing too quickly or in an uncontrollable way. When these genes get mutated or eliminated, cell division may become unrestrained, leading to the formation of tumors. Therefore, the correct answer to your question is C, tumor suppressor genes.
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Final answer:
Proteins encoded by tumor suppressor genes decrease the rate of cell division by stopping the cell cycle if DNA is damaged or signaling cell death when appropriate. They are essential in preventing cancer by opposing the action of proto-oncogenes and oncogenes. The correct answer is 'C. tumor suppressor'.
Explanation:
Proteins encoded by the tumor suppressor genes play a crucial role in controlling the rate of cell division. They act as the brakes of the cell cycle, ensuring that cells do not divide uncontrollably, which could lead to cancer. These genes produce proteins that can turn off or decrease the rate of cell division by signaling potential problems with DNA to halt the cell cycle, instigating a process called apoptosis if a cell is damaged beyond repair, or through contact inhibition which prevents overgrowth due to cellular density.
On the contrary, proto-oncogenes and oncogenes are involved in promoting the cell cycle and division. However, when proto-oncogenes are mutated or expressed too much, they can become oncogenes that contribute to unregulated cell division and cancer. DNA repair genes and DNA replication genes play different roles in maintaining genomic integrity and the process of replication, respectively, but are not directly responsible for 'turning off' the cell division.
The correct answer to the question is C. tumor suppressor, as these genes are responsible for suppressing tumor growth by controlling the rate of cell division.
Which of the following chemicals opens us binding sites allowing muscle filaments to connect to each other? Select one:
a. ATP
b. glucose
c. sodium
d. calcium
Answer:
The correct answer will be option-D.
Explanation:
Calcium plays an important role in muscle contraction as they are released from the sarcoplasmic reticulum after they receive electric impulse.
Calcium triggers the muscle contraction cycle as these calcium ions bind to the troponin-tropomyosin complex. This binding exposes the myosin-binding site on the actin on which high energy myosin binds and cross-bridge is formed.
This cross-bridge formation causes the contraction of the sarcomere and therefore muscle contracts.
Thus, option-D is the correct answer.
The structure(s) that may carry either urine or sperm in the male pig is(are):
a. ureter
b. bladder
c. urethra
d. penis
e. a and b
f. c and f
g. b, c and d
h. all of the above
Answer: d. penis
Explanation:
In pigs some of the parts of the excretory system are related to the reproductive system. The urethra is the tube where the urine get collected from the urinary bladder so as to release through the external orifice. The urethra remains connected to the penis. The vas deferens are the tubes which drains the sperms from the testes into the urethra. The urine as well as the sperms are both drained into the urethra which are finally carries away and excreted out from the body by another tube like structure that is penis.
Three of the following are evidence that charophytes are the closest algal relatives of plants. Select the exception.
a. similar sperm structure
b. the presence of chloroplasts
c. similarities in cell wall formation during cell division
d. genetic similarities in chloroplasts
Answer:
b. the presence of chloroplasts
Explanation:
The presence of chloroplast is a character being common to all the groups of green algae (to which charophytes belong) but also to plants, if one associates "plants" to the group formed by non vascular plants (mosses and relatives), non seeded vascular plants (ferns and lycophytes) and seeded plants (conifers or gymnosperms and flowering plants or angiosperms).
Thus, as the presence of chloroplasts is common throughout all these groups, it does not provide any taxonomic relevant information to particular link the charophytes to the land plants (or embryophytes, all the taxa above mentioned) as their closest relatives.
Option B- The presence of chloroplasts is not unique evidence of the close relationship between charophytes and plants. Similarities in sperm structure, cell wall formation during cell division, and genetic similarities in chloroplasts are more specific indicators of their close evolutionary relationship.
Explanation:Among the options you have provided, the correct one that doesn't serve as evidence that charophytes are the closest algal relatives of plants is b. the presence of chloroplasts. While it is true that both charophytes and plants have chloroplasts, the presence of chloroplasts is not a unique characteristic to these groups alone. Chloroplasts are found in a variety of photosynthetic organisms, including other types of algae. Therefore, the presence of chloroplasts does not specifically indicate a close relationship between charophytes and plants.
On the other hand, a. similar sperm structure, c. similarities in cell wall formation during cell division, and d. genetic similarities in chloroplasts all provide strong evidence for the close evolutionary relationship between charophytes and plants.
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