Answer:
Some bacteria are used as indicators because if they are present in the product, we can say that it is a product with the presence of pathogens that will cause diseases. Some of them are: total coliforms, fecal coliforms and enterococci.
To be a good indicator they must have a correlation with the pathogens and be more abundant than them. Its presence in a food indicates the possible presence simultaneous pathogen microorganisms. For example, E. coli has been used as Index of possible presence of pathogens of enteric origin in water and food
_______are a group of very small, pleomorphic bacteria without cell walls, previously thought to be viruses, because they are capable of crossing bacterial filters.
A) Mycoplasma
B) Clostridia
C) Anthrax
D) Spirochetes
Answer:
A) Mycoplasma
Explanation:
This kind of bacteria does not have a cell wall.
This is why it's so difficult to kill them with antibiotics that block cell wall synthesis like penicillin. They do not respond to them.
Atypical pneumonia and some pelvic inflammations are caused by this kind of bacteria.
____ is a type of weathering where rock is dissolved by an acid
Answer:
Chemical Weathering is a type of weathering where rock is dissolved by an acid
Explanation:
The weathering of rocks by chemicals is called chemical weathering . Rainwater is naturally slightly acidic because carbon dioxide from the air dissolves in it. Minerals in rocks may react with the rainwater, causing the rock to be weathered. Some types of rock are easily weathered by chemicals.
Answer:
Chemical Weathering is a type of weathering where rock is dissolved by an acid
Explanation:
Weathering are of two types- Mechanical and Chemical Weathering. In chemical weathering, the molecular structure of different rocks and soils change through chemical reactions.
For example, in carbonation the carbon dioxide of air and often soil mixes with water. This combination forms a acid named carbonic acid that dissolves rock. It especially dissolves the limestone rock. Through the dissolving of limestone huge caves are formed.
Make connections Imagine you want to study one of the human crystallins, proteins present in the lens of the eye (see Figure 1.8). To obtain a sufficient amount of the protein of interest, you decide to clone the gene that codes for it. Assume you know the sequence of this gene. How would you go about this?
Answer:
In order to clone the sequence of the gene for one of the human crystallins found in the eye, there is a need for the application of polymerase chain reaction. In the process, the particular sequence of gene is denatured and then replicated various times to generate various clones of the gene sequence.
By producing various copies of the gene sequence for the human crystallin, that is, desirable, a scientist can examine various distinct characteristics of the protein as there is always more to examine with.
How can a stem cell contain the same genetic information, yet specialize as bone cells nerve cells, muscle cells and connective tissue cells?
Answer: All cells in the body contain the same DNA, but different RNA, according to which proteins need to be synthesized.
Explanation:
DNA is the molecule that contains the genetic information necessary to generate proteins. This is due to the sequence of nucleotides, which are monomers of DNA. Each nucleotide contains a different base: Adenine (A), Timine (T), Guanine (G), Cytosine (C). But when the cell needs to synthesize proteins, DNA is not used directly but transcribed into RNA. This RNA is directed to the ribosomes, organelles where protein synthesis takes place, and according to the sequence of RNA (which is complementary to DNA), a different amino acids is coded. During translation, aminoacids are joined together to form proteins.
All cells in the body contain the same DNA, but different RNA, according to which proteins need to be synthesized. For example, a stem cell can give rise to any specialized cell in the body such as a nerve or muscle cell. All three have the same DNA but a nerve cell specializes in the transmission of impulses and neurotransmitters so it will replicate only the DNA genes that are necessary for this and this is how only part of the genetic material is replicated into RNA. The same goes for the muscle cell, which needs genes necessary for force and motion.
Briefly explain why the heart can be considered to be two pumps side by side. What is the function of each pump?
Answer: There are two pumping systems because the right side receives blood from the body and pumps it to the lungs, and the left side receives blood from the lungs and pumps it through the body. Thereby there are two pumping systems.
Explanation:
The heart is an organ that pumps blood throughout the body through the circulatory system. Its function is to supply oxygen and nutrients to the tissues and remove carbon dioxide and waste products.
The heart is divided into two separate pumps. The right side of the heart receives oxygen-poor blood from the veins and pumps it to the lungs, Over there, the blood picks up oxygen and gets rid of carbon dioxide, wich is a waste product. On the other hand, the left side receives oxygen-rich blood from the lungs and pumps it throughout the body. This blood enters the top chamber of the right heart, called the right atrium.
So, the right side of the heart receives blood from the body and pumps it to the lungs. The left side of the heart does the opposite. Thereby there are two pumping systems.
Just as in mitosis, cohesin is an important protein that keeps chromatids together during meiosis and is similarly targeted by separate as well. In the context of meiosis, however, there are multiple variants of cohesin with different quaternary structures. Why do you think this is necessary?
Answer:
It is well known that in biological compounds, such as proteins; a small change on its structure modifies its function to send a different signal or even to not have a function at all.
Talking about cohesin, this protein has been implicated in the development of certain types of tumors, because it takes a fundamental role in the cellular division and the 3D structure of the genome. Cohesin SA1, for example, maintains differentiated the TADs and it is essential for the organization of the topological domains of the genome, while the Cohesin SA2 is much more versatile and can regulate the expression of the genes within TADs, it is also capable to bond to some transcription factors creating local loops.
Some mutations on this protein can also be involved in the origin of rare diseases.
Tuberculosis is caused by the pathogen Mycobacterium tuberculosis, which currently latently infects nearly a third of the world's population. It is thought that host fatty acids can serve as a sole carbon source during infection. How does M. tuberculosis most likely metabolize fatty acids as an energy source?
A) By converting the fatty acids directly to glucose, which is then oxidized via glycolysis and the citric acid cycle
B) By a process called beta-oxidation, in which two carbon groups are removed to form acetyl-coA that enters the citric acid cycle and is oxidized to form ATP and reducing power.
C) By substrate level phosphorylation that removes phosphate groups from the fatty acids and transfers them to ADP to form ATP.
D) By reducing them and taking the electrons and protons and entering them into the electron transport chain to set up a proton motive force to generate ATP via ATP synthase.
Answer:
Option B is correct.
Explanation:
By a process called beta-oxidation, in which two carbon groups are removed to form acetyl-coA that enters the citric acid cycle and is oxidized to form ATP and reducing power.
Describe the key events of meiosis that explain Mendel's first and second laws.
Answer:
Explained
Explanation:
During Meiosis the Chromosomes line up or assort independently from one another. Therefore, genes located on each chromosomes are also segregate of one another. Therefore, the gene for seed color (G & g) will assort independent of the gene for plant height (T & t) , thus producing 4 different gene combinations of gametes,they are : GT, Gt, gT & gt.
What is meant by the statement "life is diverse?"
A. There are many living organisms on Earth
B. Each living thing is a unique individual.
C. All living things are related to each other.
D. There are many different kinds of living organisms on Earth
E. There are many places to live on Earth.
Answer:
Option (D)
Explanation:
Diversity in simple words means variations. By the given statement "life is diverse", it means that there are various types of life forms on earth. These variations occur in different places under different conditions. The factors that affect diversity are as follows-
(1) Biotic factors
(2) Abiotic factors
(3) Geographical factors
This diversity occurs in three forms and they are as follows-
(a) Ecological diversity
(b) Species diversity
(c) Genetic diversity
Hence, the correct answer is option (D).
Before Baby A was born, she was not sending much blood to her lungs. Instead, the blood passed through the septal defect into the left atrium, which sent it to the left ventricle and to her body. But why didn't the baby die if no blood was going through her lungs?
(A) She was so small that the small amount of blood that did go through her lungs was enough
(B) She was getting her oxygen from placenta, not from breathing
(C) Before the last trimester, babies use anaerobic respiration, so she did not need oxygen
(D) She sent her blood out into her mother's body and through her mothers lungs instead
The right answer is B.
The purpose of breathing is to do homeostasis, which means, to take CO2 out and get oxygen to our blood.
Babies live into the wound surrounded by liquid, so they don't need to breathe with their lungs.
All the things they needed to survive are taken from the mother thought the placenta.
Answer:
The correct answer is option (B) "She was getting her oxygen from placenta, not from breathing".
Explanation:
In order to get the oxygen we need to live is necessary that the blood gets through our lungs. If an unborn baby has a problem that does not allow her to get blood to her lungs, she is still able to survive because she could get her oxygen from placenta, not from breathing. Placenta has a respiratory function that allows the baby for fetal oxygen supply and fetal carbon dioxide removal.
Reliability refers to the ability of a test to produce consistent results each time it is administered
a. True
b. False
Answer: a. True
Explanation:
Reliability can be define as the consistency in the results or measure. A test is said to be reliable if the results obtained are repeated the same. For example, if a test is designed to observe and measure the trait, then each time the test is administered to the subjects, the results obtain will be approximately the same.
There are 4 molecules racing to get across a typical cell membrane.
(a) C6H12O6
(b) CO2
(c) Cl -
(d) CH3CH2CH2COOH (a fatty acid).
Predict the order they make it across.
(A) a, b, c, d
(B) b, d, a, c
(C) c, a, b, d
(D) d, c, d, b
(E) b, c, a, d
1. D
2. D
hope this helps
Which of the following sequences in double-stranded DNA is most likely to be recognized as a cutting site for a restriction enzyme?
a. AAGG
TTCC
b. GGCC
CCGG
c. ACCA
TGGT
d. AAAA
TTTT
Answer:
b. GGCC
CCGG
Explanation:
Restriction enzyme cleaves DNA at the restriction site. Restriction site has 4-8 nucleotide base pairs which are recognized by the restriction enzyme. This site usually has a palindromic sequence which means that the sequence is read as same on both the strands in 5' to 3' direction. Palindromic sequence is used because it increases the chances that both the strands are cut. Enzyme is also able to recognize the sequence no matter from which side it approaches the DNA. The enzyme also works as homodimers sometimes so having the same sequence makes the dimers easier to recognize it. Here, the sequence is GGCC in 5' to 3' direction on both the strands making it a palindromic sequence. Hence it is most likely to be recognized as a cutting site for a restriction enzyme.
Explain how the Meselson-Stahl experiment with "heavy" nitrogen showed that DNA replication is semiconservative.
Answer:
1. Bacteria where grow in a medium composed of heavy nitrogen. After several generations the bacteria DNA was composed of heavy nitrogen (heavy nitrogen is an isotope of nitrogen).
2. After several generations had passed, the bacteria were transferred to a nitrogen light medium.
3. As soon as the bacteria were transferred the bacteria DNA was isolated after the first and second generation through centrifugation.
4. Results: after 2 generations half of the DNA was intermediate and half was light; there was not heavy-only DNA. The conclusion was that the new DNA is formed by an "old" strand and a "new" strand producing an intermediate weight.
In evolution, why is it important that individuals vary from each other?
A. Variation allows some individuals to do better than others, so those variations are selected for.
B. If variations or mutations are extreme enough, new species can result.
C. Variations are important because individuals have to change through time.
D. Variations are important because they're inherited.
E. Variation gives every individual an equal chance of surviving so they can be selected for.
Answer:
D. Variations are important because they're inherited.
Explanation:
A. False
Not all variations are just beneficial, there are variations that can be harmful, leading natural selection to eliminate these individuals.
B. False
Without some environmental pressure, that is, any change that drives the selection of an individual, mutation alone cannot generate a new individual. If this mutation is not selected as "beneficial" and is not passed on to future generations, this mutation will disappear in that individual.
C. False
Not necessarily. Genetic variations occur at random, so those species that survive are selected and able to adapt.
E. False
It does not give an equal chance of surviving.
Chorionic villus sampling is a prenatal test usually performed in the second trimester.
a. True
b. False
Answer:
b. False
Explanation:
Chorionic villus sampling test is used to determine the genetic disorder or chromosomal disorder in a fetus. Chorionic villus test is done by the PCR or by FISH. This test can take place usually performed in 10 to 12 weeks gestation i.e. first trimester, before amniocentesis. Chorionic villus can be removed by a needle. Pregnancy loss in CVS (Chorionic villus sampling) is 2-3 percent. So it is highly accurate.
Chorionic villus sampling is a prenatal test performed in the first trimester, specifically at 10-12 weeks of pregnancy, not in the second trimester. It is used to diagnose genetic abnormalities and determine the sex of the fetus, offering an earlier alternative to amniocentesis.
Explanation:The statement that chorionic villus sampling (CVS) is a prenatal test usually performed in the second trimester is false. CVS is an alternative method of prenatal diagnosis to amniocentesis and is typically performed earlier in pregnancy, between 10-12 weeks, during the first trimester. This procedure involves extracting a small amount of placental tissue, either through the abdominal wall or through the vagina, which provides cells for testing. The extracted cells can be used to diagnose over 100 genetic abnormalities, including chromosomal abnormalities like Down syndrome, enzymatic defects, and determining the sex of the fetus.
Unlike amniocentesis, which is done after 14-22 weeks and involves extracting amniotic fluid to obtain fetal cells for analysis, CVS allows for earlier detection and the possibility of a simpler process if an abortion is considered. Moms-to-be are also advised to avoid substances that can be fetotoxic as these can cross the placenta and affect the developing fetus, potentially leading to disorders like Fetal Alcohol Spectrum Disorders (FASD).
Explain how a testcross can provide evidence for or against linkage.
Answer:
Testcrosses clarify linkage because each phenotypic class of progeny corresponds to each gamete type produced by the dihybrid parent.
Explanation:
A test cross involves the crossing of an individual with another phenotypically recessive individual so as to determine the zygosity of the former by analyses of the proportions of offspring phenotypes.In order to determine linkage, the test cross shows that if the parentals are more than the recombinants, we can say that the two genes such as b and c are genetically linked and therefore, they must be on the same chromosome.Also, the test-crosses help to find out which alleles came from which parent.By setting up testcrosses in which one parent is homozygous for the recessive alleles of both genes,we can analyze the gene combinations received in the gametes from the other, doubly heterozygous parent.Each of these practices has greatly reduced the spread of infectious diseases in the developed world except
A) vaccination.
B) antibiotics.
C) reduced population growth.
D) water purification.
Answer:
C) Reduced population growth
Explanation:
Vaccination avoids that an infectious agent causes a disease in a person, so it stops the spread of these diseases. Also, antibiotics kill bacteria responsible for infections in an ill person, therefore, they also end the spread. Water purification eliminates pathogens from the water such as bacteria or fungus, so it helps to prevent infections in a population. Finally, reducing the growth of the population doesn't directly affect the spread of infectious diseases.
The citric acid cycle occurs in the:
a. Golgi apparatus
b. Thylakoid lumen
c. Mitochondrial matrix
d. Across the inner membrane of the mitochondria
Answer:
The correct answer will be option-C.
Explanation:
Cellular respiration is a slow process which breakdown the food components via oxidation to convert them into energy molecules. The respiration proceeds in four stages: Glycolysis, pyruvate decarboxylation, citric acid cycle and electron transport chain.
All these processes take place in different compartments of the cell-like glycolysis takes place in the cytoplasm and citric acid cycle or Kreb cycle takes place in the matrix of the mitochondria. The matrix of the mitochondria provides the necessary environment to proceed the step of the respiration.
Thus, option- C is the correct answer.
Choose one property of water that makes it unique. Describe the property and explain the chemical or physical reason that causes water to have that property.
Answer:
Water has a pH value of 7. It is colorless and has a fixed boiling point at 100 Degree Celsius.
Explanation:
Answer: Water has many properties in it which makes it unique. This is because the reason water is known as universal solvent.
Explanation:
The water is considered as universal solvent because it has the ability to dissolve many solutes in it.
This ability of water is due to the presence of hydrogen bonding which dissolves different types of solutes in water.
The presence of hydrogen bonding in water provides it some more properties like surface tension, adhesion, cohesion.
Products of glycolysis include:
a. a total of 2 ATP
b. a net gain of 4 ATP
c. 2 pyruvate molecules
d. all of the above
The products of glycolysis include a net gain of 2 ATP and 2 pyruvate molecules, so the correct answer is 'all of the above'.
Explanation:The correct answer to the question, 'Products of glycolysis include' is d. all of the above. This is because glycolysis, a pivotal process in cellular respiration, indeed yields these outcomes. First, there is a net gain of 2 ATP, meaning that while four ATP molecules are produced during glycolysis, two are consumed, resulting in an overall gain of 2 ATP. Secondly, 2 pyruvate molecules are produced during the final phase of glycolysis. Therefore, answering all of the above is accurate considering these facts.
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The products of glycolysis include a total of 2 ATP, a net gain of 4 ATP, and 2 pyruvate molecules.
Explanation:
The products of glycolysis include:
a total of 2 ATPa net gain of 4 ATP2 pyruvate moleculesTherefore, the correct answer is d. all of the above. Glycolysis is the first step in cellular respiration and occurs in the cytoplasm of cells. It is an anaerobic process that breaks down glucose into two molecules of pyruvate, resulting in a net gain of 2 ATP (although 4 ATP are produced in total, 2 ATP are used during glycolysis).
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Some of our neurons (cells of our nervous system) have ATP-gated calcium (Ca+2) channels in both their plasma membrane and nuclear envelope. (tricky
a. True
b. False
Answer:
The given statement is true.
Explanation:
Some of the neurons possess ATP-gated calcium channels in both their nuclear envelope and plasma membrane. The majority of the ion channels are ligand-gated and stays in their position, which shows that they do not move from one membrane to another.
However, the ATP gated calcium channels have been located in both the nuclear envelopes of some of the neurons and plasma membrane, which signifies that the channel may socialize between the two compartments.
List and describe the function of each of the four components of blood.
Answer:
The four components of blood are RBC, WBC, Platelets, and blood plasma.
Explanation:
The major 4 components of blood are RBC, WBC, platelets, and plasma. Plasma is the fluid part of the blood and the remaining 3 are the cellular part.
Plasma is the yellow color liquid. In the plasma, all cellular components float. Plasma constitutes approximately 55% of the total volume of the blood.
The various functions of plasma are - It carries different nutrients from the alimentary canal to the liver and other parts of the body. Simultaneously it carries the CO2 from the different tissues and reaches them to lungs for expiration. It distributes the hormones and vitamins from endocrine glands to different target organs. Plasma also plays a role in the water balance in the body. It supplies water to tissues and receives excess water from them. Thus regulate the water balance in the body.
RBC is the enucleated cellular organelle of blood. The absence of nucleus enables it to carry more oxygen. It is red due to the presence of Hb and carries O2 and CO2 in the form of oxyhemoglobin and carbaminohemoglobin. It also helps in releasing energy through the metabolic process.
WBC is concerned with the immunity of the body. It acts as a defense mechanism of the body. The components of leukocytes such as granulocytes and agranulocytes are phagocytic. They engulf bacteria and viruses. Eosinophils fight against the allergic reaction in the body.
The blood platelets have blood clotting factors. There are 12 blood clotting factors which help in the clotting of blood.
Why would you not expect amylase to digest protein?
What feature distinguishes male embryo from female at eight weeks of age?
a. males have a Y chromosome
b. males have well developed primary reproductive organs
c. male testes have descended into the scrotum
d. in males, the ovaries have degenerated
e. all of the above
Answer:
A, B & D
Explanation:
It is not possible to distinguish the sex of a fetus below seven (7)weeks. At this stage only observation of chromosomes through karyotype can determine the sex. The male fetus will have an XY sex chromosome pair while females will have an XX chromosome pair. After the eighth weeks internal and external genitalia begins to differentiate. The testes and ovaries (the primary reproductive organs) begin to develop in males and females respectively. In males the paramesonephric ducts regresses while the mesonephric ducts begin to develop into testes. In females the mesonephric ducts regresses while the paramesonephric ducts begin to develop into ovaries.
Both plant and animal cells have a chloroplast.
a. True
b. False
Answer:
False
Explanation:
Only plants have chloroplast.
This statement is FALSE. Only plant cells contain a chloroplast.
Hope this helps you
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The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is
a. oxygen. b. water. c. NAD+. d. pyruvate.
Answer: a. oxygen
Basically what (/the) ETC and oxidative phosphorylation is, is the products of the Krebs cycle being oxidized and oxygen receiving electrons. And when the phosphorylation part of oxidative phosphorylation occurs is when ADP gains its third phosphate group becoming ATP.
Forgive me for this poor response I was trying to be quick and it resulted in this vague and disorganized mess. To properly explain the ETC and oxidative phosphorylation it would be best to start from the beginning and explain all the stages of Aerobic respiration. Then it would be easier to Segway in to this final stage which would definitely take 2-3 descriptive paragraphs to cover.
The final electron acceptor in the electron transport chain during aerobic oxidative phosphorylation is oxygen. This is because oxygen combines with hydrogen ions and electrons to form water at the end of this process.
Explanation:The final electron acceptor in the electron transport chain during aerobic oxidative phosphorylation is oxygen (option a.)
Here's why it's oxygen: Aerobic oxidative phosphorylation is the process during which ATP (the main energy source for most cellular functions) is produced. This process happens in the mitochondria of our cells, and it's a part of cellular respiration.
In this process, the electron transport chain plays a vital role. Electrons travel down the chain, moving from one protein complex to the next. These electrons ultimately combine with hydrogen ions and oxygen to form water. Thus, oxygen acts as the final electron acceptor in the chain.
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Consider this pathway: epinephrine → G protein-coupled receptor → G protein → adenylyl cyclase → cAMP. Identify the second messenger.
a. cAMP
b. G protein
c. GTP
d. adenylyl cyclase
Answer:
a. cAMP
Explanation:
Secondary messengers are signaling molecules which are present intracellularly and play a great role in amplification of a signal during signal transduction pathway.
cAMP, DAG and IP3 are common secondary messengers in GPCR signalling. GPCR are largest family of cell surface receptors which are associated with various functions like control of blood vessel dialation, interstitial epithelial cells, glycogen breakdown, inflammation, photoisomerization reaction etc.
The second messenger in the given pathway is cAMP.
Explanation:The second messenger in the given pathway is cAMP. In this pathway, epinephrine binds to a G protein-coupled receptor, which activates a G protein. The G protein then activates adenylyl cyclase, an enzyme that converts ATP into cAMP. Therefore, cAMP acts as the second messenger in this pathway.
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The final product of the Calvin cycle is:
a. RuBisCo
b. ATP
c. CO2
d. G3P
Answer:
The correct answer will be option-D
Explanation:
Calvin cycle or C₃ cycle is a set of a cyclic reaction which takes place in the light-independent reactions of photosynthesis. Calvin cycle proceeds in three phases: carboxylation, reduction and regeneration.
The cycle produces two molecules of Glyceraldehyde-3-phosphate (G3P) molecule during the reductional step of the cycle. Out of these two molecules, one G3P undergo for the regeneration of RuBP and one G3P undergo for the formation of a glucose molecule.
Thus, option-D is the correct answer.
Now that you have come up with an equation that describes the relationship between amounts of different nucleotide bases in DNA, can you use it to predict the amounts of all four nucleotide bases when you only know the amount of one type of base? Approximately 21% of the human genome is comprised of nucleotides containing C. Given this information, calculate the percentage of the human genome that is comprised of nucleotides containing G, T, and A.
Answer:
G=21 %
T= 29 %
A= 29 %
Explanation:
Since C only binds to G, you have the same amount of C and G, so G is 21 %.
100 % minus 42 % ( 21 % C plus 21 % G=) equals 58 %.
So the other 58 % is made of T and A. Since T only binds to A , the half of the extra 58 % is T and the other half is A. Therefore 29 % is T and 29 % is A