The system of regulation in bacteriophage life cycle operates under negative control, as the temperate phage remains inactive until stressors induce the lytic cycle.
Explanation:The regulation of the lytic and lysogenic cycles in bacteriophages can be characterized as being under negative control. In a lysogenic cycle, a temperate bacteriophage's DNA integrates into the bacterial chromosome as a prophage. During this state, several operons maintain the prophage state by interacting with a repressor that prevents the initiation of the lytic cycle.
When environmental stressors such as ultraviolet light or toxic chemicals affect the bacterial cell, they lead to the breakdown of the repressor. This, in turn, causes the production of enzymes involved in the lytic cycle. Because the repressor actively inhibits the lytic cycle under normal conditions, and a stress-induced breakdown of the repressor is required to initiate the lytic cycle, this system of regulation is considered to be operating under negative control.
In sheep, coat color is influenced by two genes. Gene A influences pigment production, while gene B produces black or brown pigment. If two heterozygous white sheep were crossed and offspring were produced in a ratio of 12 white sheep to 3 black sheep to 1 brown sheep, what are the genotypes of the offspring?
Answer:
White: A---
Black: aaB-
Brown: aabb
Explanation:
The given example represents dominant epistasis wherein the gene A masks the effect of gene B. Hence, all the genotypes having at least one copy of "A" allele will have white coat color (A---).
On the other hand, in absence of "A" allele, the "B" allele would be able to express itself. Hence, all the genotypes that have two copies of recessive "a" allele and atleast one "B" allele (aaB-) would have black coat color.
The brown coat color would be expressed in double homozygous recessive genotypes (aabb) only.
In sheep, when two heterozygous white sheep are crossed, resulting in a phenotypic ratio of 12 white:3 black:1 brown sheep, this demonstrates epistasis. White sheep could have various genotypes indicating a lack of pigment or color expression, black sheep would have AaBb genotype, and the rare brown sheep could be aaBB.
In the scenario described, where coat color in sheep is influenced by two genes - Gene A for pigment production and Gene B that decides the color of the pigment (black or brown), we observe an example of epistasis. Cross-breeding two heterozygous white sheep resulted in offspring with a phenotypic ratio of 12 white:3 black:1 brown. To understand the genotypes of the offspring, we must assign gene symbols. Let's say 'A' (dominant) allows pigment production, while 'a' (recessive) does not; and 'B' (dominant) codes for black pigment, while 'b' (recessive) results in brown pigment. The absence of A (aa genotype) results in white coat color regardless of the B gene's allele, which is an example of epistasis. Given the ratios, the probable genotypes for the offspring would be:
White sheep: aabb, Aabb, aaBb, or any combination where at least one gene lacks the dominant allele necessary for color expression.Black sheep: AaBb, which have the necessary alleles from each gene to produce pigment and determine it to be black.Brown sheep: aaBB, lacking the dominant A for pigment production but possessing the dominant B allele, resulting in brown pigment in the few cases where pigment is produced.This demonstrates the interaction between multiple genes in determining an organism's phenotype, specifically through the mechanism of epistasis.
What is the consensual response (the response of the left eye)?
Answer:
Constriction of pupil of left eye in response to entry of bright light in right eye.
Explanation:
The consensual response is a reflex response towards the intensity of light. When the right eye is exposed to the bright light, there is constriction of its pupil mediated by iris to regulate the amount of light entering the eye ball. However, at the same time, the pupil size of the left eye is also reduced to limit the amount of light entering the eye. This response of the left eye towards the exposure of the right eye for bright light is called consensual response.
Cytotoxic T (Tc) cells are like a natural killer (NK) cell because they both
A. secrete interferons.
B. secrete granzymes and perforin.
C. participate in the immune response.
D. participate in nonspecific resistance.
Answer:
B. secrete granzymes and perforin.
Explanation:
Perforins are the proteins that perforate the plasma membrane of the target cell and lead to bursting of cells due to holes formed in its membrane. Granzymes are the proteolytic enzymes. They serve to stimulate the target cells to kill themselves by the process of apoptosis.
Binding of natural killer cells to their target cells stimulate the release of granules that are filled with perforins or granzymes to kill the target cells.
Likewise, cytotoxic T cells bind to the infected body cells and release the granules filled with perforins or granzymes to kill those infected cells.
Carbon dioxide is transported by all the following means except
A. carbaminohemoglobin.
B. carbonic acid.
C. carbonate
D. bicarbonate ions.
Answer:
C. Carbonate
Explanation:
i juST KNOW
Carbondioxide is not transported through carbonate. That is option C.
Transportation of carbondioxideCarbon dioxide is a chemical compound that is made up of two oxygen atoms covalently bonded to a single carbon atom.
In the human body, carbondioxide can be transported through three following means;
As carbonic acid : Here it is dissolved directly in the blood.As carbaminohemoglobin: Here it is bound to plasma proteins or hemoglobin.As bicarbonate ions: Here it is converted into bicarbonate.They are not transported as carbonate but through bicarbonate.
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Jessica travels to a remote village in the Amazon jungle in order to work as a medical volunteer. While in this village, Jessica discovers a new animal species that has a very selective diet. She observes that this specific species eats only fruit and plant products. Intrigued by this new animal species and its unique diet, Jessica decides to study the alimentary canal of this organism. One finding that is particularly interesting to Jessica, however, is the mucosal layer of the stomach. She notes that one cell is missing.
Which of the following cells would most likely be missing from the new species’ stomach mucosa?
a) Chief cell, because it releases pepsin, an enzyme necessary for the digestion of proteins.
b) Goblet cell, because this organism does not need to release mucus along the alimentary canal.
c) Enteroendocrine cell, because this organism does not need to absorb as many food products.
d) Paneth cell, because this organism will not need to secrete substances that destroy bacteria.
Answer: Option A
Explanation:
The chief cells in the alimentary canal of the organism releases an enzyme which is helpful in the digestion of the protein.
The name of the enzyme id pepsin which is not required much in the body of the organism who feeds on the plants and plant extracts.
This is because the plants have higher amount of carbohydrates in it and less source of protein.
Hence, for the digestion of cellulose, pepsin is not required.
Helppp!!!! What type of tissue is this ??? Nervous tissue, muscle tissue, connective tissue, or epithelial tissue???
Answer: Connective tissue
Explanation: So, this is not exactly nervous or epithelial tissue. In all probability it is connective tissue
Answer:
Explanation:
my guess is epithelial tissue
True or False. The most toxic of our metabolic wastes are nitrogenous wastes.
Metabolic wastes are substances left over from metabolic processes. The answer is true.
dominant over the mutant vermilion (bright red) allele. A homozygous wild-type female fly is mated with a vermilion male fly. Predict the eye colors of F1 and F2 generations. (Assume that the F1 flies are allowed to interbreed to produce the F2 generation.)
.................................................................
Glycosaminoglycans are unbranched polysaccharides consisting of alternating residues of uronic acid and hexosamine. Which of the following is NOT a glycosaminoglycan? a. heparin b. chondroitin-4-sulfate c. agaropectin d. dermatan sulfate e. hyaluronate
Answer:
It's agaropectin which is a charged polymer
The _______ is (are) responsible for the red blood cell's ability to transport oxygen.
A. hemoglobin
B. leukocytes
C. platelets
D. hematocrit
Answer:
(A). hemoglobin
Explanation:
Hemoglobin is iron-containing protein, present in RBCs (red blood cells) of nearly all vertebrates and some invertebrates. It is made up of four globular protein units.
The main function of hemoglobin is to transport oxygen to the different parts of the body. The oxygen is requires by the body cells to perform cellular respiration that generates energy in the form of ATP molecules.
Thus, the correct answer is option A.
_________ is the cranial nerve that controls sense of smell.
Answer: Olfactory nerves
When the level of ADH (antidiuretic hormone) decreases
A) more urine is produced
B) less urine is produced
C) the osmolarity of the urine decreases
D) both A and C
E) both B and C
Answer:
(A). more urine is produced.
Explanation:
ADH (antidiuretic hormone), also known as vasopressin is a peptide hormone, which is synthezied in hypothalamus and is secreted by posterior pituitary gland.
ADH plays role in osmoregulation as it is responsible for water retention by decreasing urine output when there is low level of water in body.
As ADH is responsible for decreased urine formation, more urine will be produced due to decrease in ADH that would lead to an increase osmolarity of urine.
Thus, the correct answer is option (A).
ADH regulates the body's water balance. When ADH levels decrease, more urine is produced and the osmolarity of the urine decreases. Thus, the correct answer is both A and C.
Explanation:Antidiuretic hormone (ADH), also known as vasopressin, is a hormone that plays a significant role in controlling the body's water balance. When the level of ADH decreases, the kidneys are less stimulated to reabsorb water, resulting in more urine being produced (option A) and the osmolarity of the urine decreases (option C). Thus the correct answer would be option D: both A and C. ADH's prime function is to conserve the fluid volume of your body by reducing the amount of water passed out in the urine.
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Which nutrient is most closely related to the liver's ability to produce necessary clotting factors?
A) Iron
B) Vitamin E
C) Vitamin K
D) Folic Acid
Answer:
Vitamin K
Explanation:
Vitamin K is a fat soluble vitamin and plays an important role in the bone metabolism. Two important compounds of Vitamin K are Vitamin K1 and Vitamin K2.
Vitamin K is synthesized in the liver and helps in the coagulation of blood. Vitamin K acts as a coenzyme for vitamin K-dependent carboxylase. This enzyme is important for the synthesis of proteins that are involved in blood coagulation and bone metabolism.
Thus, the correct answer is option (C).
Plzzzz help
As time goes by and water goes through the water cycle again and again, the amount of water
on Earth:
increases
decreases
Ostays the same
goes up and down
One of the primary functions of this tissue type is to store energy.
Answer:
Adipose tissue
Explanation:
Adipose tissue is an example of loose connective tissue. The cells of the adipose tissues are filled with droplets of fat. When there is a need for energy and glucose is not available as an energy source, the stored fats enter the catabolic pathway to produce energy in the form of ATP. The proportion of stored fat in adipose tissues is as high as 80%.
Hence, adipose tissues are the connective tissues that serve to store energy in the form of fat droplets.
protons and neutrons are found together in the part of the atom called the
The nucleus
the protons and neutrons are in the nucleus and the electrons revolve around the nucleus
The embryos of a bird, a reptile, and a mammal are similar in appearance. How does comparing the physical appearance of embryos of different species support the theory of evolution?
a. it shows that these organisms share a common ancestor.
b. it provides evidence that these organisms eat the same foods.
c. it shows that these organisms share the same habitat.
d. it provides evidence that these organisms suffered a genetic mutation.
Answer:
I believe the answer is A.
Explanation:
Species may share similar physical features because that feature was present in a common ancestor. These features are known as homologous structures.
Answers b, c, and d sound probable, but those responses of foods, habitat, and genetic mutation don't directly correlate with the theory of evolution.
For example: In option d, these organisms all most likely suffered from a genetic mutation, but the similarity of the embryos does not prove that.
The correct answer is A. It shows that these organisms share a common ancestor.
Explanation:
In biology, the Theory of Evolution was first proposed by Darwin and Wallace and this explains organisms evolve or change over time which means their genes and physical traits are not static but the result of changes in previous generations mainly influenced by environmental changes that make certain traits prevail over others. In the same way, in this theory, changes in species lead to new species and this implies all living organism and even those that are already extinct have one common ancestor and this was the origin of all species as changes in genes and traits or evolution took place.
This idea is supported with different types evidence and one of this is that different types of animals such as birds, reptiles, and mammals look almost identical in the embryonic stage which shows they share common features but as the embryon develops certain features are shown over others. Therefore, comparing the physical appearance of embryos support the theory of evolution as it shows that these organisms share a common ancestor.
Involved in allergic and hypersensitivity reactions, SELECT ONE:
A. IgA
B. IgD
C. IgE
D. IgG
E. IgM
Answer: IgE
Explanation:
Allergic reactions and hypersensitivity are the reactions which are produced in the body due to the invasion of a foreign antigen. In response to the invasive antibodies are produced in the body. The IgE is the special antibody that is produce in response to the invasive antigens. These antibodies instruct the cells to produce substances which produces the allergic response in the body.
Acetyl co A can
A) Enter the citric acid (Krebs cycle)
B) Combine with another acetyl co A
C) Be converted to glycerol
D) Be converted to glycerol
E) Both a and b are correct
Answer:
Both a and b are correct.
Explanation:
Acetyl co A or acetyl coenzyme A is a chemical molecule that plays an important role in the biochemical reactions. This molecule acts as an intermediate molecule in various reactions.
Acetyl co A delivers the acetyl group in the citric acid cycle. Acetyl co A can also combine with another acetyl co A during the synthesis of fatty acid.
Thus, the correct answer is option (E).
It is the structure that marks the division between the right and left lobes of the liver.
Answer:
falciform ligament
Explanation:
Falciform ligament’s is the structure which divides the liver into two lobes – right and left. It is a sickle shaped structure which connects the ventral body wall to the liver. It is the remaining part of fetus’s ventral mesentery and consist of fat between its layers. It is situated at the anteroposterior plane and connect to the left lobe from its back.
Sympathetic vs parasympathetic nervous system define and contrast
Answer:
Sympathetic nervous system:
Sympathetic nervous system helps the body to prepare at conditions such as threat and danger. This system increases the heart beat and cause muscle contraction. This system is referred as "fight or flight" system.
Parasympathetic nervous system:
Parasympathetic nervous system controls the body to prepare at rest. This system maintains the homeostasis, decreases the heart beat and causes the relaxation of muscles. This system is referred as "rest and digest" system.
A small, rounded depression on a bone that is meant for articulation is called a(n)
a. fossa
b. trochanter
c. tuberosity
d. condyle
e. foramen
Answer:
Condyle
Explanation:
The condyle is one of the outgrowth or projections present at the surface of the bone. The condyle is large and round in shape. It has a smooth articular surface and serves in joints formation. The condyle is present at the end of one bone and joins it with other bones.
Example: occipital condyles of occipital bone serve in joint formation with the first vertebra of the vertebral column.
A small, rounded depression on a bone that is meant for articulation is called a fossa. It is a hollow or depression that helps connect other structures like muscles or other bones.
Explanation:In the field of biology, specifically in the study of human or animal anatomy, a small, rounded depression on a bone that is meant for articulation is called a(n) fossa. This is a specific type of bone landmark, where other structures, such as muscles, tendons, or other bones, would connect. To help remember this, think of a 'fossa' as a hollow or depression in a bone that helps to form a joint. It's different from a trochanter, which is a large, rough projection, a tuberosity, which is a moderate protuberance where muscles and connective tissues attach, a condyle, that is a smooth, rounded articulating area, and a foramen, which is a hole that allows passage of nerves and or vessels.
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An example of working memory is
a) the ability to recall an address from your childhood
b) the ability to remember a phone number you learned yesterday
c) the ability to repeat a task such as solving a 3-dimensional puzzle
d) the ability to remember a brief list of ingredients in a recipe and what to do with them
Answer: A
Explanation:
An example of working memory is the ability to remember a phone number you learned yesterday. Thus, the correct option is B.
What is Working memory?Working memory may be defined as the amount of information that can be stored in the mind and utilized in the execution of cognitive tasks. It is a part of short-term memory.
Working memory always deals with the remembrance of address, contact number, etc in the mind while listening to instructions on a specific topic that was made earlier in the past few days.
Therefore, the correct option for this question is B.
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After compounds are absorbed through the villi of the small intestine: (a) They travel to the kidneys, which excrete absorbed, but unwanted water-soluble compounds (b) They travel to the kidneys, which screen for unwanted compounds that have been absorbed and begin to detoxify so they can be eliminated. (c) They travel to the liver, which excretes absorbed, but unwanted water-soluble compounds (d) They travel to the liver, which screens for unwanted compounds that have been absorbed and begins to detoxify so they can be eliminated.
Answer:
the answer is a.
Explanation:
the small intestine absorbs the nutrients in digested food, then the kidneys where the liquid waste is formed into urates for excretion.
In 1994, telomerase activity was discovered in human cancer cell lines. Although telomerase activity is rarely present in human somatic tissue, this discovery indicated that humans do contain the genes for telomerase proteins and telomerase RNA. Since inappropriate activation of telomerase may contribute to cancer, why do you think the genes coding for this enzyme have been maintained in the human genome throughout evolution?
Answer:
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Telomerase is crucial for cell division and immortality in specific cells. Its presence in the human genome is supported by its roles in cell proliferation, regeneration, and combating age-related diseases and cancer.
Telomerase is an enzyme responsible for maintaining and elongating telomeres, critical for cell division and immortality in certain cells.
The presence of telomerase genes in the human genome throughout evolution is thought to be maintained due to its role in cell proliferation, regeneration, and potential implications in age-related diseases and cancer.
While inappropriate telomerase activation can contribute to cancer, its essential function in certain cells for telomere length maintenance and cellular immortality justifies its presence in the human genome.
Describe the function of three areas of the brain (you choose which areas).
Answer:
Brain is the main coordination center of the body and regulates the proper functioning of the body. Brain is divided into three parts- forebrain, midbrain and hindbrain.
Cerebrum: Crerebrum is the largest part of brain and controls the language, communication ability, and the process of learning and memory of an organism.
Hypothalamus: Hypothalamus is located at the base of a brain. Hypothalamus releases various hormones, regulates the body temperature and manages the sexual behavior of an organism.
Thalamus: Thalamus is located above the brain stem and relay the neurons into the cerebral cortex. Thalamus regulates alertness, wakefulness and sleep of an organism.
Final answer:
The cerebrum controls higher brain functions and is divided into four lobes, each with distinct functions. The cerebellum coordinates muscle movements and maintains balance. The brain stem regulates vital life functions and connects the brain to the spinal cord.
Explanation:
The human brain is an intricate organ responsible for controlling many functions of the body, understanding complex thoughts, facilitating communication, and more. In the study of biology, it is essential to understand the different areas of the brain and their specific functions. Three critical areas of the brain are the cerebrum, cerebellum, and brain stem.
The cerebrum is the largest part of the brain and is responsible for higher brain functions such as thought and action. The cerebrum is divided into four lobes: the frontal lobe, responsible for reasoning, planning, parts of speech, movement, emotions, and problem-solving; the parietal lobe, which manages perception of stimuli related to touch, pressure, temperature, and pain; the temporal lobe, concerned with perception and recognition of auditory stimuli, memory, and speech; and the occipital lobe, dedicated to visual processing.The cerebellum is located under the cerebrum. Its main function is to coordinate muscle movements, maintain posture, and balance. This part of the brain is vital for performing activities that require fine motor skills, balance, and coordination, such as typing or playing a musical instrument.Connecting the brain to the spinal cord, the brain stem plays a crucial role in regulating vital life functions, including breathing, consciousness, and controlling heart rhythms. It is also responsible for various automatic functions necessary for survival, such as digestion and sleeping cycles.
The specific receptors responsible for rotation found in the semicircular canals is called
a. Ampulla
b. Vestibule
c. Auricle
d. Saccule
e. Crista
Answer:idn
Explanation:
The respiratory membrane is composed of fused basement membrane of the capillary walls and the ____________.
Answer:
Type l cells.
Explanation:
because according to my knowledge of science, the correct answer to this question is Type l cells.
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During the _______ phase, the muscle is returning to resting length.
Answer:
The correct answer is: Eccentric phase.
When talking about movement, we are talking about the activation of muscle fibers in order for this process to happen. In order for this to happen, motor neurons must activate the phases of muscle excitation, contraction and relaxation, so that the sarcomeres, and thus the fibers, can generate movement.
In essence, there are three stages, or phases, to complete muscle movement: the concentric phase, which is when the muscle fibers are excited and begin the process of contraction. This means the muscle fibers will contract and generate movement, generating a shortening. Then we have the isometric stage, a moment in which there is no longer any more shortening of the muscle fibers, so basically, the movement is held and there is no further contraction, but neither is there relaxation of the muscle fibers. Finally, we have the eccentric phase. This phase is characterized precisely because it is the moment when the muscles begin to return to their resting position.
Define depolarization.
Answer:
According to Dictionary.com, "depolarize" means:
a sharp division, as of a population or group, into opposing factions.the deposit of gases, produced during electrolysis, on the electrodes of a cell, increasing the resistance of the cell.