Answer:
False (The statement is true for pelvic girdle)
Explanation:
The pectoral or shoulder girdle is the set of bones in the appendicular skeleton (a portion of the skeleton that supports appendages) which connects to the arm on each side i.e. it connects upper limbs (arms) to the bones along the axis of the body.
In humans, the pectoral girdle is made up of two major bones viz: clavicle/collar bone and scapula/shoulder blade. These two bones which attaches the upper limbs to axial skeleton forms the pectoral girdle. Although, in species with three bones, coracoid bone is included in its formation.
The pelvic girdle is formed by the hip bone, which is the point of attachment for each lower limb (legs). The hip bone attaches the lower limb to the axial skeleton via its articulation with the sacrum. The sacrum is a triangular bone formed by the fusion of vertebrae and located in between the right and left hip bones. The association of the right and left hip bones, sacrum and coccyx forms the pelvis.
Theodor W. Engelmann illuminated a filament of algae with light that passed through a prism, thus exposing different segments of algae to different wavelengths of light. He added aerobic bacteria and then noted in which areas the bacteria congregated. He noted that the largest groups were found in the areas illuminated by the red and blue light.If you ran the same experiment without passing light through a prism, what would you predict?A) There would be no difference in results.B) The bacteria would be relatively evenly distributed along the algal filaments.C) The number of bacteria present would decrease due to an increase in the carbon dioxide concentration.D) The number of bacteria present would increase due to an increase in the carbon dioxide concentration.E) The number of bacteria would decrease due to a decrease in the temperature of the water.
Answer:
The correct answer will be option-B
Explanation:
Theodor Engelmann performed the experiment to study the relationship between the production of oxygen in response to the wavelength of light. This was observed by the congregation of the bacteria in the red and blue wavelength.
In the given condition, if no light is passed through prism then the bacteria will not be accumulated in a particular area instead will be evenly distributed as the algae will produce the oxygen evenly and the concentration is not high in any particular area.
Thus, Option-B is the correct answer.
Final answer:
Without a prism to separate light into its components, aerobic bacteria would likely be relatively evenly distributed along the algal filaments since all areas would receive red and blue light uniformly, resulting in more uniform oxygen production across the algae.
Explanation:
The experiment conducted by Theodor W. Engelmann involved illuminating a filament of algae with light from a prism, which allowed different segments of the algae to be exposed to different wavelengths of light. The addition of aerobic bacteria to this setup led to the observation that the bacteria congregated in areas where the red and blue light illuminated the algae, indicating that these areas had the highest rates of photosynthesis and oxygen production.
If the same experiment were conducted without the prism, so that the algae were exposed to uniform white light containing all wavelengths, based on Engelmann's results, the prediction would be that the bacteria would be relatively evenly distributed along the algal filaments. This is because all areas would receive red and blue wavelengths equally, alongside other wavelengths, so the oxygen production should in theory be more uniform across the entire filament of algae without the prism separating the light into its component colors.
Therefore, the correct prediction for what would happen if the same experiment were run without passing light through a prism is: B) The bacteria would be relatively evenly distributed along the algal filaments.
AZT is an effective drug for treating HIV-infected individuals because it prevents the replication of new viral particles. The HIV virus has a genome made of RNA. Of the following, which represents the most likely target for the action of AZT?a. DNA polymeraseb. RNA polymerasec. reverse transcriptased. DNA ligase
Answer:
Enzyme reverse transcriptase RT
Explanation:
This enzyme is what is needed by the virus to make several copies of itself. Reverse transcriptase is inhibited by this drug thereby reducing the numbers of the virus. The drug is a nucleoside analog of thymidine
Which structure does very little albumin escape from the blood during glomerular filtration?
a. Fenestrated endothelium
b. Basement membrane
c. Filtration pore
d. Juxtaglomerular apparatus
e. Macula densa
Answer:
b. Basement membrane
Explanation:
Together, the endothelial cells of the glomerular capillaries and the podocytes that completely surround the capillaries form a permeable barrier called filtration membrane or endothelial capsular membrane. This sandwich arrangement allows filtration of water and small solutes, but prevents filtration. of most plasma proteins, blood cells and platelets. The filtered substances move from the bloodstream through three barriers: a gIomerular endothelial cell, the basal lamina and a filtration slot formed by a podocyte.
1 The endothelial cells of the gIoméruIo are quite permeable because they have large perforations (pores) of 70 to 100 nm (0.07 to 0.1 ml) in diameter. These dimensions allow all solutes of the blood plasma to leave the gIomerular capillaries, but prevents blood cells and platelets from leaking. The mesangial cells, contractile cells that help regulate gIomerular filtration are located in the middle of the gomeromer capillaries and the groove formed between the afferent and efferent arterioles.
2 The basement membrane is a layer of acellular material between the endothelium and podocytes, which consists of fibruses in a gIucoprotein matrix; prevents filtration of large plasma proteins.
3 From each podocito thousands of extensions in the form of feet called pedicels that surround the glomerular capillaries extend. The spaces between the pedicels are called filtration cracks. A thin membrane, the crack membrane, extends through each filtration crack and allows the passage of molecules with a diameter smaller than 6 to 7 nm (0.006 to 0.OO7 mm), including water, glucose, vitamins, amino acids , very small plasma proteins, ammonia, urea and ions. Since the most abundant plasma protein, albumin, has a diameter of 7.1 mm, less than 1% of it crosses the membrane of the crack.
All the following are true of the movement of Earth's atmosphere except :
a.cool air is denser than warm air so it tends to sink toward the Earth's surface.
b.the movement of air within the atmospheric convection cells generates the Earth's major wind belts.
c.a column of cool, dense air produces high pressure at the Earth's surface. a column of warm, less dense air produces low pressure at the Earth's surface.
d.warm air is less dense than cool air so it tends to sink toward the Earth's surface.
Final answer:
The accurate statement about Earth's atmosphere movement is that warm air rises because it is less dense, and cool air sinks due to higher density. This creates convection currents which are essential in generating wind belts and pressure systems.
Explanation:
The correct answer to 'All the following are true of the movement of Earth's atmosphere except:' with the listed statements is option d: warm air is less dense than cool air so it tends to sink toward the Earth's surface. This statement is false because in reality, warm air is less dense and therefore it tends to rise, not sink. This rising of warm air and the sinking of cooler air form convection currents, which are a major factor in the movement of Earth's atmosphere.
The rest of the statements are true: a. cool air is denser than warm air so it tends to sink, b. the movement of air within the atmospheric convection cells generates the Earth's major wind belts, and c. a column of cool, dense air produces high pressure at the surface while a column of warm, less dense air produces low pressure.
As children grow, they generally consume more calories, decide if they want to eat, and how much they want to eat. What is the rule-of-thumb guideline to determine an age-appropriate serving size for a 3-year-old?
A) 3 teaspoons
B) 2 tablespoons
C) 3 tablespoons
D) Equal to that of an adult
Answer:
Option C
Explanation:
In general, the amount of nutrient served to an adult is equal to 50% of the nutrient served to adults. The amount of calories consumed by an adult is equal to 2000 to 2800 calories per day. Therefore, the calories required by a young kid is equal to 1000 to 1400 calories per day. Considering this, a nutrient feed of 3 tablespoon is sufficient to cater the calorie requirement of young children of age above 3 years
Hence, option C is correct
The sharp, inch-long thorns of the crown-of-thorns sea star are its spines. These spines, unlike those of most other sea stars, contain a potent toxin. If it were discovered that crown-of-thorns sea stars do not make this toxin themselves, then the most likely alternative would be that this toxin is _____.
A) derived from the nematocysts of its prey
B) absorbed from the surrounding seawater
C) an endotoxin of cellulose-digesting bacteria that inhabit the sea star's digestive glands
D) injected into individual thorns by mutualistic corals which live on the aboral surfaces of these sea stars
Answer:
The answer is A) derived from the nematocysts of its prey.
Explanation:
Sea stars mostly eat cnidarians (mollusks) which can contain a large number of nematocysts in their bodies. Therefore it would be possible that this toxin is absorbed from the prey.
Which of the following definitions is INCORRECT? Which of the following definitions is INCORRECT? epidemic: a disease that is constantly present across the world endemic: a disease that is constantly present in a population pandemic: a disease that affects a large number of people in the world in a short time incidence: number of new cases of a disease
Answer:
epidemic: a disease that is constantly present across the world.
Explanation:
An epidemic is a sudden outbreak of a disease that spreads over a large area within a short period.
Endemic disease is a disease that is found regularly within an area at every point in time.
Pandemic disease is a disease that is prevalent over the whole world within a short period.
Incidence is the number of newly reported cases of a disease.
From the definition of each of the term. epidemic is the only one defined incorrectly of all the options.
The incorrect definition is that of an endemic disease, which is correctly defined as a disease that is always present at low incidence, not high incidence, in a population.
Explanation:The definition provided in the question that is INCORRECT is that of an endemic disease. The correct definition is that an endemic disease is one that is constantly present, usually at low incidence, in a population, not at high incidence as suggested in one of the erroneous definitions. In contrast, an epidemic is an outbreak of a disease that occurs in an unusually high number of individuals within a population at the same time. A pandemic is an epidemic that becomes widespread across multiple populations or continents, or even worldwide. Incidence refers to the number of new cases of a disease that appear in a population during a specific period of time. These terms are crucial for understanding the spread of diseases and for public health management.
Codons are three-base sequences in mRNA that specify the addition of a single amino acid to the growing protein chain during translation. How do eukaryotic codons and prokaryotic codons compare?
Answer:
There is no difference between Eukaryotic and prokaryotic codons. All 61 codons and 20 amino acids are same. Start codons are also same.
The genetic code is essentially universal, with both eukaryotic and prokaryotic organisms using the same mRNA codons to specify the addition of amino acids or the termination of protein synthesis during translation. The start codon is typically AUG, and it also codes for the amino acid methionine. The uniformity of the genetic code across different life forms suggests that all life on Earth shares a common origin.
Explanation:Codons are three-nucleotide sequences in mRNA that specify the addition of a specific amino acid or the termination of protein synthesis during translation. There are 64 possible mRNA codons comprising of combinations of A, U, G, and C. Out of these, three are stop codons that indicate the termination of protein synthesis. Typically, AUG is the start codon for initiating translation, and it also encodes for the amino acid methionine.
The genetic code, which is the relationship between an mRNA codon and its corresponding amino acid, is essentially universal and alike for both eukaryotic and prokaryotic organisms, implying that all life on Earth shares a common origin. Such a universal genetic code strongly supports the theory of common descent for all life on Earth.
Learn more about mRNA Codons here:https://brainly.com/question/29764228
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In the caterpillar, molting and metamorphosis are under the control of the same hormone. What is the hormone? How are these separate developmental pathways controlled by the same hormone?
Answer:
The correct answer will be- 20-hydroxyecdysone
Explanation:
Ecdysone is a steroid hormone produced in the Arthropods which plays an important role in coordinating and regulating the different developmental transitions like larval moulting and the metamorphosis.
The other effector hormone also plays an important role in molting and metamorphosis called Juvenile hormone.
The presence of juvenile hormone prevents the ecdysone induce changes which regulate molting and gene expression during metamorphosis.
Therefore the presence of the juvenile hormone leads to the different stages of molting while the absence of juvenile hormone promotes the development of metamorphic stages like the development of pupa.
Thus, 20-hydroxyecdysone is the correct answer.
When two frog species, Rana pipiens and Rana sylvatica, mate, the offspring die early in embryonic development. This is an example of ________.
a) hybrid sterility
b) reduced hybrid fertility
c) reduced hybrid viability
d) mechanical isolation
Answer:
The correct answer is c) reduced hybrid viability.
Explanation:
As the offspring dies early in embryonic development, it's possible to understand that the organism isn't viable, which is very common among hybrid organisms as well as their sterility or reduced fertility.
At the conclusion of an interventional radiographic examination, the examination room is cleaned and major components are wiped down with chemical disinfectants. By performing this important task the radiographer is practicing_________.a. medical asepsis.b. sterilization.c. surgical asepsis.d. fomite asepsis
Answer: A medical asepsis
Explanation:
Medical Asepsis: this is one of the principles of sterile techniques. It is the state of having a sterile equipment and facility free from disease causing micro-organisms such as germs, bacteria, viruses, and other diseases causing microorganisms.
The answer is Medical asepsis and it is concerned mainly with eliminating the spread of disease causing microorganisms through facility practices, to prevent the spread of disease microorganisms from one patient to another.
If a person loses a large amount of water in a short period of time, he or she may die from dehydration. ADH can help reduce water loss through its interaction with its target cells in the
A) Anterior pituitary.
B) Posterior pituitary.
C) Adrenal gland.
D) Bladder.
E) Kidney.
Answer:
E because ADH is found is the hormones found in the kidney
Look at the cross section of a cell membrane of a eukaryotic cell. H+ ions are being pumped from a low concentration to a high concentration. transport How do you describe this type of transport across the cell membrane?
Answer:
it is an active transport
Explanation:
Active transport involves movement of ions or molecules against a concentration gradient (from region of lower concentration to region of higher concetration) using energy from hydrolysis of ATP as the drive
Answer:
Active Transport is the answer
Explanation:
Given the following cross between parents of the genotypes AABBCc × AabbCc, assume simple dominance for each trait and independent assortment. What proportion of the progeny will be expected to phenotypically resemble the first parent?
Answer:
3/4
Explanation:
The first parent with the "AABBCc" genotype would express the dominant trait for all the three loci since the mentioned loci exhibit simple dominance for each trait and independent assortment. Therefore, the desired progeny should also exhibit the dominant trait for all three loci.
Parents= AABBCc × AabbCc
AA x Aa= 1/2 AA (dominant): 1/2 Aa (dominant) = 100% dominant progeny
BB x bb = Bb (dominant) = 100% dominant progeny
Cc x Cc = 1/4 CC (dominant): 1/2 Cc (dominant): 1/4 cc (recessive) = 3/4 dominant : 1/4 recessive progeny
Therefore, the proportion of the progeny showing the dominant trait for all the three loci= 1 x 1 x 3/4 = 3/4
Final answer:
The proportion of progeny from the cross AABBCc × AabbCc that will phenotypically resemble the first parent is 3/4, considering the dominance of traits and independent assortment.
Explanation:
The question involves the cross between two parents with genotypes AABBCc and AabbCc, with simple dominance for each trait and independent assortment. To determine the proportion of progeny that would phenotypically resemble the first parent, we consider each gene independently due to the principle of independent assortment.
For gene A, the first parent is AA and the second parent is Aa. Since A is dominant, all offspring will have the dominant phenotype (A), just like the first parent.
For gene B, the first parent is BB and the second parent is bb. Since B is dominant, all offspring will be Bb, displaying the dominant phenotype as the first parent.
For gene C, the first parent is Cc and the second parent is Cc. This gene will produce offspring with a 3:1 phenotypic ratio in favor of the dominant C phenotype, according to Mendel's principle of dominance.
Because the offspring must display the dominant phenotype for all three traits to resemble the first parent phenotypically, we calculate the probability as a product of the probabilities for each gene, which is 1 (for A) × 1 (for B) × 3/4 (for C), giving a final proportion of 3/4.
When examining the two complementary strands of nucleotides in one DNA molecule, it would be expected that the sum of ________ in one strand would be ________ the sum of the ________ in the other strand.
Answer: Purine; is equal to; pyrimidine
Explanation:
When a segment of DNA is examined then the nucleotide in one DNA molecule, it will be expected that the sum of purine in one strand will be equal to the sum of the pyrimidine in the other strand.
Adenine combines with Thymine and Cytosine combines with Guanine in 1:1 ratio.
More specifically the ratio of purine is to pyramidine is 1:1 in an organism. This pattern is seen in both the strands of the DNA.
Final answer:
When examining the two complementary strands of nucleotides in one DNA molecule, it would be expected that the sum of adenine (A) in one strand would be equal to the sum of the thymine (T) in the other strand, and vice versa.
Explanation:
Similarly, the sum of guanine (G) in one strand would be equal to the sum of the cytosine (C) in the complementary strand. This relationship is due to the rules of base pairing, where adenine always pairs with thymine, and guanine pairs with cytosine.
These rules are fundamental to the structure of DNA and its replication process, ensuring that each new molecule is an accurate copy of the original.
A biochemist isolates, purifies, and combines in a test tube a variety of molecules needed for DNA replication. When she adds some DNA to the mixture, replication occurs, but each DNA molecule consists of a normal strand paired with numerous segments of DNA a few hundred nucleotides long. What has she probably left out of the mixture?a. DNA ligase
b. nucleotides
c. DNA polymerase III
d. Okazaki fragments
Answer:
a. DNA ligase
Explanation:
DNA ligase is the enzyme of DNA replication that joins DNA segments together by catalyzing the formation of new phosphodiester bonds. These reactions use the energy of ATP molecules to form the bonds. The function of the DNA ligase enzyme is to join the Okazaki fragments together which in turn are formed during replication of the lagging strand. In the absence of DNA ligase, the Okazaki fragments cannot be joined together.
According to the given information, the process of DNA replication obtained shorts DNA segments of a few hundred nucleotides. This means that the reaction mixture lacked the DNA ligase enzyme and the DNA segments could not be joined together.
Some nutrients and other types of particles can be taken into a cell when the cell’s plasma membrane encloses the particles and pinches off. True or False
Answer:
True
Explanation:
The particles takes up by the cell from extracellular side and allow their fusion with the plasma membrane. The process is called endocytosis. The large molecules that are polar in nature like hormones and proteins are absorbed by cell. The polar molecules are unable to cross plasma membrane that is hydrophobic in nature. Thus simple diffusion is not possible for polar molecules.
Thus, Some nutrients and other types of particles can be taken into a cell when the cell’s plasma membrane encloses the particles and pinches off is true.
Ruth is quite attractive (a 4 on a 5-point scale), but Naomi is strikingly attractive (a 5 on a 5-point scale). Research suggests that if Ruth makes $35,000 a year on her job, Naomi will probably make _____ doing the same job. slightly less money the same amount more money significantly less money
A. Slightly less money
B. the same amount
C. More money
D. Significantly less money
Answer:
The correct answer is C. More money.
Explanation:
There' a correlation that has been studied, between physical appearance and the money that people get paid. It's a psychological factor that leads to handsome people being paid more and not so pretty people being paid less. Therefore, as Naomi is more attractive, she will be paid more.
Which of the pictured cell types influences neuronal function by ""mopping up"" leaked potassium ions and by recapturing and recycling released neurotransmitters? These cells also participate in information processing in the brain.
Answer:
Astrocytes
Explanation:
In the central nervous system, astrocytes, also collectively known as astroglia, are distinctive star-shaped glial cells.
It is not well known the ratio of astrocytes in the brain.
Research has found that the astrocyte proportion varies by area depending on the counting technique used and varies from 20% to 40% among all glia.
These fulfill many roles, namely biochemical reinforcement of tumor cells that build the blood-brain barrier, nutritional supply to the nervous tissue, extracellular ion balance maintenance, as well as a function in the brain and spinal cord repair and scarring cycle after severe injuries.
1.List and describe the structural components of viruses.
2. Explain why viruses are obligate intracellular parasites.
3. Explain how a virus identifies its host cell.
4. Describe bacterial defenses against phages.
5. Distinguish between the lytic and lysogenic reproductive cycles, using phage as an example.
6. Describe the reproductive cycle of an HIV retrovirus.
7. What are several catagories of Virus and how do they differ?
8. List some characteristics that viruses share with living organisms and explain why viruses do not fit our usual definition of life.
9. Define and describe mobile genetic elements. Explain why plasmids, transposons, and viruses are all considered mobile genetic elements. Viruses, Viroids and Prions.
10. Explain how viral infections may cause disease.
11. Describe the three processes that lead to the emergence of new viral diseases.
12. Distinguish between the horizontal and vertical routes of viral transmission in plants.
13. Describe viroids and prions.
Answer:
A virus is a fragment of code embedded in a legitimate program. Virus are self-replicating and are designed to infect other programs. They can wreak havoc in a system by modifying or destroying files causing system crashes and program malfunctions. On reaching the target machine a virus dropper(usually trojan horse) inserts the virus into the system.
For more details, refer this.
Various types of virus :
File Virus : This type of virus infects the system by appending itself to the end of a file. It changes the start of a program so that the control jumps to its code. After the execution of its code, the control returns back to the main program. Its execution is not even noticed. It is also called Parasitic virus because it leaves no file intact but also leaves the host functional.
Boot sector Virus : It infects the boot sector of the system, executing every time system is booted and before operating system is loaded. It infects other bootable media like floppy disks. These are also known as memory virus as they do not infect file system.
boot sector virus flowchart
Macro Virus : Unlike most virus which are written in low-level language(like C or assembly language), these are written in high-level language like Visual Basic. These viruses are triggered when a program capable of executing a macro is run. For example, macro virus can be contained in spreadsheet files.
Source code Virus : It looks for source code and modifies it to include virus and to help spread it.
Polymorphic Virus : A virus signature is a pattern that can identify a virus(a series of bytes that make up virus code). So in order to avoid detection by antivirus a polymorphic virus changes each time it is installed. The functionality of virus remains same but its signature is changed.
Encrypted Virus : In order to avoid detection by antivirus, this type of virus exists in encrypted form. It carries a decryption algorithm along with it. So the virus first decrypts and then executes.
Stealth Virus : It is a very tricky virus as it changes the code that can be used to detect it. Hence, the detection of virus becomes very difficult. For example, it can change the read system call such that whenever user asks to read a code modified by virus, the original form of code is shown rather than infected code.
Tunneling Virus : This virus attempts to bypass detection by antivirus scanner by installing itself in the interrupt handler chain. Interception programs, which remain in the background of an operating system and catch viruses, become disabled during the course of a tunneling virus. Similar viruses install themselves in device drivers.
Multipartite Virus : This type of virus is able to infect multiple parts of a system including boot sector,memory and files. This makes it difficult to detect and contain.
Armored Virus : An armored virus is coded to make it difficult for antivirus to unravel and understand. It uses a variety of techniques to do so like fooling antivirus to believe that it lies somewhere else than its real location or using compression to complicate its code.
Answer: 1. nucleoid, capsid, envelope, enzymes.
A. Nucleoids represents the viral chromosomes, it is made up of single molecular which is either linear or coiling.
B. Capsid is the proteinacious covering around the virus that protects the nucleoids from damage and it consists of subunits called capsomere and campaigners.
C. Envelope is the loose membrane covering that occur in some viruses consisting of protein from lipids and carbohydrates(from host).
D. Enzymes are occasionally enzymes lysozymes is present in the region that comes in contact with host cell in bacteria pages.
2. Due to their nature of behaving like simple chemical compounds outside the living host.
3. Virus recognises it's host cell through the receptors they carry and virus can also trick the cell into taking them by bulk transport called endocytosis.
4. The development of CRISPR immune system to fight against phages.
5. Lytic involves reproduction of viruses by using host cell for virus manufacturing while lysogenic cycles involves integration of viral genome into host DNA and reproducing with it.
6. The life cycle of hic
a. Attachment and entry- this happens in two stages attachment and fusion.
B. Reverse Transcription- when hiv enters the cell it must be reverse transcribed into proviral DNA before integrating into the DNA of host.
C. Integration- after conversion into DNA, hiv integrate enzyme attaches itself to the proviral DNA strands it passes through the wall of cell nucleus.
D. Transcription and Translation- they become active when they encounter an infectious agent.
7. Bacterial viruses are classified under viruses that affect the ecoil.
-DNA phages of T series where the T phages of ecoil are larger lyric phages that contain single molecule of double stranded DNA
-Temprate pages: bacterial phage lambda
-Small DNA phage: the genome of some bacteria phage encoded 10-12 protein
-RNA phage- some e coil bacterial phage contains a genome composed of RNA instead of DNA.
B. ANIMAL viruses are classified by genome type and MNRA synthesis path way.
-DNA viruses (classes 1 and 2) commonly used in the study of DNA replication.
-RNA viruses(classes 3 and 4) have RNA genome and all animal cells belong to this class.
8. They are made of protein.
They contain genetic codes needed for reproduction.
-viruses do not fit our normal life because viral reproduction is not possible without a host cell and it doesn't consume energy to survive that is metabolic processes within the cell.
9. The DNA sequences which can move around the genome changing their number of copies or location often affecting the nearest genes.
- plasmids and trasposoons are mobile transferable genetic elements through bacterial conjugation which is a horizontal mechanism gene transfer while viruses can move due to their adaptive replication strategy.
10. They cause infectious diseases by entering a living and normal cell, thereby using the cell to reproduce other viruses of them selves and infecting the immune system of the living cell.
11. -introduction of viral pathogens into a new host species.
-establishment of pathogens in New host.
-dissemination of pathogens among large number of individual of new host species.
12. In a nut shell, transmission of viruses occur horizontally is the transmission of viruses among plants of same generation while vertical transmission is between full grown plants and the seed from it to ensure transmission from current generation to the next generation.
13. Virions is the infectious form of viruses as it exists outside the host cell designed for transmission of nucleic acid genome amongst hosts while a prion is neither bacterial nor fungal nor viral and contains no genetic materials.
Explanation:2. They have long and non living thing characteristics in nature.
4. This is an act of copying a snipet of phages they come in contact with into a memory to help build against subsequent attacks by viruses in future.
6. The life cycle of hiv consists of 4 stages which includes the process of entering , reverse integration where the RNA enzymes reverse transcribed into DNA , integration where it passes through the walls of the cell and finally the last stage where it becomes activated.
N.B
Most of the answers required explanations above in order to avoid repetition of answers.
Stamens are composed of:_______ Please choose the correct answer from the following choices, and then select the submit answer button.
A) stems and styles.
B) stigmas and ovaries.
C) anthers and filaments.
D) stigmas and filaments.
E) stems and anthers.
Answer:
C: anthers and filaments
Explanation:
The stamen is the male reproductive structure of flowers. It is made up anthers which houses the pollen grain and the filament which serves as a channel for transporting nutrient to nourish pollens.
The number of stamen a flower possesses varies from plant to plant. Some flowers have as few as one half while some have thousands of stamens. Collectively, stamens form the same flower are referred to as androecium. The stamens in some flowers join to form a tube, otherwise known as staminal tube.
The correct option is C.
The process in which related dna sequences from two different sources are exchanged is called
Answer: Homologous Recombination
Explanation:
In DNA recombination, homologous recombination is a type of gene repair in which nucleotide sequences are exchanged between two identical molecules of DNA.
When DNA damages occur such as DNA double-stranded breaks or DNA gaps during DNA synthesis.
To conserve genome, cells uses a homologous recombination (HR), a type of DNA repair.
In genetic engineering a foreign DNA with identical nucleotide sequence similar to that of the missing DNA gaps or breaks are introduced into a target cell. The cell recognizes the identical DNA sequences as homologues, causing target gene to be exchanged with the foreign DNA sequence during DNA repair.
HR also occur naturally.
Crossing over is the exchange of DNA sequences between non-sister chromatids of homologous chromosomes during meiosis I, leading to recombinant chromosomes and increased genetic variation.
Explanation:The process in which related DNA sequences from two different sources are exchanged is known as crossing over. This biological mechanism occurs during meiosis I, when homologous chromosomes pair closely together. During crossing over, non-sister chromatids exchange genetic material, which results in the formation of new combinations of genes, or recombinant chromosomes.
The purpose of crossing over is to increase genetic diversity within a species. It is a critical part of sexual reproduction and ensures that offspring have a unique combination of DNA from both parents, leading to genetic variation within a population. The process is also known as recombination, and the points where the chromatids break and rejoin are called chiasmata.
There is a misconception that girls cannot inherit recessive X-linked disorders. Girls can in fact inherit these disorders, but at a lower rate than boys. The following choices give the genotypes for pairs of mothers and fathers. Which pair of parents could have a daughter with the recessive disorder a?
Choose one:a. XAXA × XAYb. XAXA × XaYc. XAXa × XAYd. XAXa × XaY
Answer:
d. [tex]X^{A}X^{a}[/tex] × [tex]X^{a}Y[/tex]
Explanation:
Since the disorder is a recessive one, the daughter will need to inherit two recessive alleles, each one from the two parents in order for the disorder to manifest.
A cross between [tex]X^{A}X^{a}[/tex] and [tex]X^{a}Y[/tex] will yield the following offspring;
[tex]X^{A}X^{a}[/tex] female, carrier of disorder
[tex]X^{a}X^{a}[/tex] female, affected with disorder
[tex]X^{a}Y[/tex] male, affected with disorder
[tex]X^{A}Y[/tex] male, unaffected
Hence, the only parental pair that can have a daughter with the recessive disorder is [tex]X^{A}X^{a}[/tex] × [tex]X^{a}Y[/tex]
The correct option is d.
During which processes does independent assortment of chromosomes occur?
Independent assortment occurs during anaphase I of meiosis I and to some extent during metaphase II and anaphase II, leading to the formation of gametes with diverse combinations of paternal and maternal chromosomes.
Explanation:Independent assortment of chromosomes occurs during meiosis, a critical process for producing genetically diverse gametes in eukaryotic organisms. Specifically, this event takes place during anaphase I of meiosis I, where bivalent chromosomes separate, and again, although indirectly, during metaphase II and anaphase II as sister chromatids segregate. During the phase of prophase I, chromosomes align randomly at the metaphase plate, setting the stage for the independent assortment. The physical basis for the law of independent assortment lies here, as different homologous pairs line up in random orientations, allowing any combination of paternal and maternal chromosomes to segregate into each gamete, thus increasing genetic variation.
Additionally, recombination or chromosomal cross-over during meiosis further increases genetic diversity by producing new combinations of alleles. At the end of meiosis II, four different gametic combinations are produced, each containing a haploid set of chromosomes. As the number of chromosomes increases, the number of possible assortment combinations increases dramatically, leading to a vast potential for genetic diversity.
Pea flowers may be purple (P) or white (p). Pea seeds may be round (R) or wrinkled (r). What proportion of the offspring form a cross between purple-flowered round-seeded individuals (heterozygous for both traits) will have both white flowers and round seeds?
Answer:
3/16
Explanation:
The following is the punnet square which represents the probabilities of offsprings being produced for this cross:
PR Pr pR pr
PR PPRR PPRr PpRR PpRr
Pr PPRr PPrr PpRr Pprr
pR PpRR PpRr ppRR ppRr
pr PpRr Pprr ppRr pprr
This cross shows that the probability of the offsprings to have white flowers and rounded seeds would be 3/16.
Which of the following correctly lists in order the four stages of food processing in animals? View Available Hint(s) Which of the following correctly lists in order the four stages of food processing in animals? ingestion, digestion, absorption, elimination ingestion, digestion, elimination, absorption ingestion, absorption, elimination, digestion digestion, ingestion, absorption, elimination
Answer:
ingestion, digestion, absorption, elimination
Explanation:
Final answer:
The correct order of the four stages of food processing in animals is ingestion, digestion, absorption, and elimination, all vital for obtaining nutrition and managing waste.
Explanation:
The correct order of the four stages of food processing in animals is: ingestion, digestion, absorption, and elimination. During ingestion, food is taken into the body through the mouth. The process of digestion breaks down the food into smaller components that the body can use. Absorption is the stage where the body's cells take up the small molecules resulting from digestion. Finally, elimination removes indigestible substances from the body.
Each stage is crucial for obtaining nutrition and energy from food. Without ingestion, there is no food to process; without digestion, nutrients cannot be broken down; without absorption, digested nutrients cannot be utilized by the body; and without elimination, waste products would accumulate, leading to health issues.
Using the 10 percent rule, explain why there is typically smaller populations of quaternary consumers compared to primary consumers in an ecosystem.
Answer:
As we know 10% law is transfer of energy from higher trophic level to lower trophic level. So as the energy are transfer from one organism to another there is a loss of energy as that energy are utilised by the oragnism and only 10% of the total energy is transferred to the second consumer.
Explanation:
Quetinary consumer are at the higher position in the food chain so they do not get enough energy from prey they have to feed on several organism for the enegy. And also they are at the top of the food chain so they are not eaten by other animal, their life span are also more than primary consumer.
In other hand primary consumer get enough energy but they are prey for other higher tropic level.
Primary and secondary consumer are maintend in such a way by the nature thats make a ecological balance of the habitant.
What role does RNA stability play in gene regulation? List three types of RNA structural elements that can affect the stability of an RNA molecule in eukaryotic cells. Explain how these elements act to influence RNA stability.
Answer:
RNA structural elements include double stranded regions of RNA formed by RNA folding upon itself to form a hairpin loop for example. These structures provide structural stability to RNA and allows for RNA to function as enzymes in some instances.
Another RNA structural element is the polyA tail formed at the end of mRNA sequence after mRNA maturation to prevent degradation of mature mRNA by RNase.
Another RNA structural element is the 5'cap formed at the 5' of mRNA sequence after mRNA maturation to prevent degradation of mature mRNA by RNase and also acts as a signalling target for transport of mRNA.
RNA stability affects gene regulation by controlling RNA degradation rates. Key elements include: 5' Cap: Protects RNA from degradation, Poly-A Tail: Enhances stability and translation, and RNA Secondary Structures: Can mask or expose degradation signals.
Three key RNA structural elements that affect stability in eukaryotic cells are:
5' Cap Structure: This modified guanine nucleotide at the RNA's 5' end protects it from degradation by exonucleases and facilitates translation initiation. A loss of the 5' cap leads to rapid degradation.3' Poly(A) Tail: A string of adenine nucleotides added to the 3' end stabilizes the RNA and enhances translation efficiency. Shortening of the poly(A) tail triggers degradation by exonucleases.Stem-Loop Structures: These secondary structures formed by base-pairing within the RNA molecule can influence stability. They can protect the RNA from degradation by shielding vulnerable regions or signal decay pathways when specific sequences are recognized by RNA-binding proteins or ribonucleases.These elements collectively regulate RNA half-life, impacting gene expression.
Dated to approximately 500,000-400,000 years ago, the site of _______ has yielded a sample of 4,000 fossil fragments representing about 28 premodern Homo sapiens individuals, more than 80% of all Middle Pleistocene hominin remains in the world.
a. Steinheim
b. Ehringsdorf
c. Sima de los Huesos
d. Petralona
e. Swanscombe
Answer:
c. Sima de los Huesos
Explanation:
A crime scene reveals a tiny amount of genetic material that may be linked with the guilty person. This small amount of DNA may be amplified, or copied many times over, through a process called ___________ ___________ ___________.
Answer:
Polymerase Chain Reaction (PCR)
Explanation:
Polymerase chain reaction is a molecular biology procedure/technique used to amplify or multiply specific segments of a DNA. The process makes use of taq polymerase (an enzyme), primers, the DNA of interest and nucleotides.
All the reactants are subjected to repeated heating and cooling cycles during which the DNA of interest is synthesized in multiples. The process can be broken down to 3 basic steps:
Denaturation of the target DNA by heat to separate the DNA strandsBinding of primers to their complementary DNA sequence at lower temperatureSynthesis of new DNA through addition of nucleotides to primers by the taq polymerase. This happens at higher temperature than the second step but lower than the first step.The steps are repeated at the end of each cycle which can last between 2 to 4 hours depending on the length of the target DNA. Newly synthesized DNA at every cycle forms a template for the production of another strand. Hence, multiple copies of the target DNA can be produced within a short period.