Heredity and Evolution Important answers

Q1. Define Heredity. Explain the mechanism of Hereditary changes?

i. Heredity is defined as the transfer of biological characters from one generation to another via genes

ii. The mechanism of heredity is as follows

a) Heredity changes occur due to genetic variation

b) During fusion of male and female gametes, the offspring always has recombined genes of both the parents. These offspring’s thus show some characters of either of the parents.

c) Sometimes sudden changes known as mutations occur in the genes. A change in the position of even a single nucleotide can cause either a minor effect or a considerable changes in the characters of an individual.

d) If these changes (mutation) occur in DNA of germ line cells then, these changes would be inherited to the next generation.

Q2. How are the hereditary changes responsible for evolution?

i. Evolution is gradual change occurring in living organisms over a long duration.

ii. Sudden heredity changes may occur in the genes of an individual resulting in genetic variations.

iii. These genetic variations are responsible for the formation of new species

iv. According to Darwin's theory, organisms with favorable or beneficial variations survive in competition and are selected by nature whereas the others with non-favourable are eliminated.

v. This leads to formation of new species due to specific changes in specific characters accumulated through several generations in selected organisms.

Q3. Write a note on 'transcription'.

i. Transcription is the process of synthesis of mRNA from DNA. It takes place in the presence of RNA polymerase.

ii. During transcription, mRNA is produced as per the sequence of nucleotides present on the DNA.

iii. This mRNA sequence is always complementary to the DNA strand that is used for its synthesis.

iv. The thymine in DNA molecule is replaced by uracil in RNA, during the process of transcription.

Q4. Explain in detail the process of translation.

Translation is the process of synthesis of proteins after transcription of DNA to RNA. It is carried out in the following manner:

i. mRNA formed in the nucleus during transcription moves in the cytoplasm, carrying the coded message by DNA.

ii. Each mRNA contains codes for amino acids in the form of triplet codons.

iii. As per the message on mRNA, amino acids are supplied by the tRNA, which has an anticodon (complementary sequence) to the codon on mRNA.

iv. The amino acids supplied by tRNA are bound together by peptide bonds with the help of rRNA

v. The process continues as the ribosome moves along the entire length of the mRNA by the distance of one triplet codon, also known as translocation. Many chains of amino acids come together to form complex proteins.

Q5. Write a short note on evolution.

i. Evolution is defined as the gradual change occurring in living organisms over a long duration.

ii. It is a slow-going process through which development of organisms is achieved.

iii. Evolution is thus the formation of new species due to changes in specific characters of living organisms.

iv. Changes in these specific characters get accumulated over several generations of living organisms in response to natural selection.

v. It may occur due to speciation - geographical or reproductive isolation, mutation etc.

Q6. Explain the process of formation of complex proteins.

i. Around 3.5 billion years ago, it is speculated that life was non-existent on earth.

ii. In the beginning, only simple elements may have been present in the oceans.

iii. Simple organic and inorganic compounds may have been formed by these simple elements.

iv. These simple compounds may have eventually resulted in the formation of complex compounds like proteins and nucleic acids.

v. The process of formation of complex proteins from simple elements may have occurred over a long period of several years.

Q7. Explain with suitable examples importance of anatomical evidences in evolution.

i. Anatomical evidences are the similarities in the structures of bones and joints of animals that provide proof of evolution.

ii. The hand of human, foreleg of cat, flipper of whale and forelimbs of bat appear different morphologically.

iii. Also, the function of these structures is different in different animals.

iv. However, there is a similarity in the structure of bones and bony joints in the organs of these animals.

v. These similarities indicate that the animals evolved from a common ancestor.

Q8, Define fossil. Explain importance of fossils as proof of evolution.

i. Remnants and impressions of organisms that remain preserved underground are called as Fossils.

ii. Carbon consumption of animals and plants stops after death and only the decaying processes of C-14 takes place continuously.

iii. In dead plants and animals with time, the ratio of C-14 to C-12 changes constantly as C-12 is non-radioactive

iv. The time passed since the death can be calculated by carbon dating i.e. by measuring the radioactivity of C-14 and ratio of C-14 to C-12 present in the remains of the dead organism.

v. Thus, study of fossils is an important aspect of evolution since, it can be used in paleontology and anthropology for determining the age of fossils.

Q9. Write a short note on connecting link.

i. Connecting links are some plants or animals that show morphological characters by which they can be related to two different groups of organisms

ii. Peripatus is the connecting link between two different groups annelids and arthropods. It shows annelid-like characters such as segmented body, thin cuticle and parapodia-like organs. It also shows arthropod-like characters such as tracheal respiration and open circulatory system.

iii. The duck-billed platypus is a connecting link between mammals and reptiles. II shows similarity with mammals due to the presence of mammary glands and hairs. It lays eggs like reptiles.

iv. Lungfishes are connecting links between fishes and amphibians. The lungfish performs respiration with lungs even though it is a fish.

Q10. Write a short note on embryology.

i. Embryology is a branch of biology that deals with the study of different stages of development of embryo.

ii. As the developing embryo grows there is increase in complexity from differentiation of the cells into specialized tissues to form specific organs.

iii. Embryology helps us to comparatively study the developmental stages of various animals.

iv. Embryos of different vertebrates appear similar during the initial stages and these similarities decrease gradually as the embryo develops.

Q11. Explain the theory of evolution and mention the proof supporting the theory

i. According to the theory evolution the first living material (protoplasm) was formed in the ocean

ii. In the course of time unicellular organisms were formed

iii. Larger and more complex organisms were formed due to slow and gradual changes that occurred in the unicellular organisms.

iv. Through evolution, plants and animals progressively developed from their ancestors that had different structural and functional organization.

v. The proof supporting the theory of evolution arc as follows:

a) Morphological evidence: It is based on the similarity of size, shape or structure' of organs among a group of organisms proving that they evolved from the same ancestor.

b) Anatomical evidence: It is based on the similarities in the structure of bones and bony joints in the organs of animals.

c) Vestigial organs: It is based on the theory that some useless organs are degenerated or underdeveloped due to non-functionality through several years.

d) Paleontological evidence: It is based on the study of remnants and impressions of organisms that remain preserved underground as fossils.

e) Connecting links: It is related to some plants or animals that show morphological characters by which they, can be related to two different groups of organisms.

f) Embryological evidence: It arises from comparative study of embryological developmental stages of various vertebrates.

For chapter explanantion - https://www.youtube.com/watch?v=RuKAcDOxyy8&t=252s

#science #class10 #SSC #MaharashtraBoard #Heredity #Evolution #notes #answers

Meat and Immunity

First I went researching the net for foods that can enhance your immunity and I was surprised to find that in the list for top 15 foods there was 13 plant sourced foods and only 2 animal based diet. Here's the list



Yogurt

 Yogurt that contains live cultures is rich in lactobacillus acidophilus and bifidobacterium lactis (read: good bacteria), which fight bacteria that cause diseases and raise your white blood cell count.

 Green Tea

 Green tea is a great source of L-theanine, an amino acid that triggers the release of germ-fighting compounds from your T-cells. (Green tea also helps to boost your metabolism.)

 Oranges

 One of the best sources of immunity-boosting vitamin C, oranges cause your body to produce higher levels of antibodies and white blood cells.

 Garlic

 Garlic is loaded with ajoene, allicin and thiosulfinates, compounds high in sulfur that ward off diseases and help battle infections.

 Carrots

 Carrots are crammed with beta carotene, a phytonutrient that increases your body’s production of T-cells and natural killer cells.

 Spinach

 The high amount of antioxidants found in spinach help boost your immune system.

Sweet Potatoes

 Like carrots, sweet potatoes are loaded with beta carotene, which boosts your body’s T-cell and NK-cell count.

 Mushrooms

 Rich in compounds called beta glucans, mushrooms boost the production of NK-cells and T-cells in your body to help prevent infections.

 Kiwi

 Like oranges, kiwis are high in vitamin C, which helps protect your body against infections.

 Bell Peppers

 Bell peppers are packed with vitamin C, which prompts your body to produce more interferon. This antibody covers the surface of cells and fends off viruses.

 Broccoli

 Broccoli is a great source of glucosinolates, phytonutrients rich in sulfur that stimulate the natural antioxidant systems in your body.

 Barley

 Like mushrooms, barley contains a high amount of beta glucans, known for their antioxidant and antimicrobial properties.

 Animal source

 Crab and salmon.

 But before you think that even 2 sources is enough for you to savagely consume them here is another view on meat about how it affects your immunity,source:- http://www.natural-cancer-cures.com/meat-and-sugar.html

Eating Plants over animals

Yes, I've been ridiculed over eating plants which they claim to be equally sentient like animals. And I cant help myself but just to feel sorry for them, because they make them self believe what they want, instead of having a logical approach. Here Ill give a try to answer all their questions and hope to satisfy their ignorance.


 To the extent that we link the moral status of animals with cognitive characteristics beyond sentience, we continue the humanocentric arrogance that is species-ism. I need to cite 2 important drawbacks of species-ism from Gary L Francione's blog
      1. It ignores that cognitive characteristics beyond sentience are morally irrelevant for determining whether we use a being exclusively as a human resource. We see that in the human context. That is, being “smart” may matter for some purposes, such as whether we give someone a scholarship, but it is completely irrelevant to whether we use someone as a forced organ donor, as a nonconsenting subject in a biomedical experiment.
    2. It sets up a standard that animals, however much they are “like us,” can never win. For example, we have known for a long time that nonhuman great apes are very much like humans in all sorts of ways but we continue to exploit them. However much animals are “like us,” they are never enough “like us” to translate into an obligation on our parts to stop exploiting them .


The argument of plants compared to be equally sentient as animals is a way to dismiss the idea of eating animals without having to seriously consider the moral grounds.Forgets Morals first, why do we stand for animals and not for plants, the simple reason is pain. Pain is over all morals for me.The sole biological purpose of pain is to ensure that a living organism gets away from or avoids potentially life-threatening dangers. All the animals want to escape their death, I've seen sacrificial or animals waiting in the slaughter house lines to run away from the screams coming from inside. Since plants are unable to escape life-threatening situations, there is no reason to imagine that plants would have evolved a sense of pain. To explore the consciousness of plants as well as fungi and single-celled organisms, there is no better place to begin than Jeremy Narby’s book INTELLIGENCE IN NATURE. But if one truly believes that killing a carrot is as bad as killing an animal, then the moral imperative is to refrain from eating either instead of eating both.

 A final issue: Does a focus on sentience itself establish a hierarchy of the sentient over the non-sentient? No, because sentience is a necessary as well as sufficient characteristic for a being to have interests (preferences, desires, or wants) in the first place. A rock is not sentient; it does not have any sort of mind that prefers, desires, or wants anything. A plant is alive but has no sort of mind that prefers, desires, or wants anything. It would be justifiable to kill off something that has no interest in living, such as a plant, but since we believe that animals do have an interest in living it would be speciesist to kill off a puppy simply because it is not human. We know that society believes animals have an interest in living sometimes because there is outcry when baby seals are clubbed or when elephants are poached for their ivory. Yet at other times we are happy to eat animal flesh and wear leather.

 Finally, I would just like to say that this is just an introductory blog written by me. Later I will like to expand on basic ideas and questions regarding species-ism, plants sentience and moral basis. Please posts questions if you have any and I will try to answer them in my next blog.

Those who eat the meat of other [living beings] in order to satisfy their own flesh, they are definitely murderers [themselves], since without a consumer [there can be] no killer. — Acharya Hemacandra (12th c. Jain ascetic/scholar)

The Psychology of killing!!

Rather this post is about the trauma of killing. Killing someone or watching someone die in front of you is complete life changing. We talking about killing is like Virgins talking about sex! The most traumatic emotions are when to see someone pass away even if its an animal.
We easily save ourselves and our kids from this trauma and never want to experience it but I've seen even even most brave individuals completely reformed visiting the killing floor. The primary question here and we all need this to ask ourselves that do we need to distance ourselves from ask the killings that happens for us? Well i'm going to say "No" since i can't distance myself from a reality caused by me.
In an experiment certain strong individuals were placed in prehistoric environment with basic tools and asked to survive on their own. They fared well and killed certain small animals with no remorse. But that wasn't enough for survival so they tried their chance on a bigger animal. The participants can never forget their arrows piercing that Swamp deer. The complete trauma of separating the animal from the herd, hitting with a dart, then finally putting him down upon collapsing by spear was unbearable for all of them and most of them cried.

In such cases i find myself correct when i assert that we are not ought to kill here as we are not natural killers. Man has always hidden this fact for himself by developing easy killing methods and faster methods. But he has never justified that killing. The destruction of all the emotions of a being for your interests can never be justified.
The only thing that i can never decipher is that how can we ever manage to ignore the basic and important facts and processes of your life. ask your small child where this nuggets came from and he'll answer 'supermarket'.
I think Time has come when we at least answer ourselves!!1

Biofuels.

Biofuels are produced from living organisms or from metabolic by-products(organic or food waste products). In order to be considered a biofuel the fuel must contain over 80 percent renewable materials. It is originally derived from the photosynthesis process and can therefore often be referred to as a solar energy source. Biofuels include fuels derived from biomass conversion, as well as solid biomass, liquid fuels and various biogases. 'First-generation' or conventional biofuels are biofuels made from sugar, starch, and vegetable oil. Second generation biofuels are biofuels produced from sustainable feedstock.
Biodiesel was probably the first of the alternative fuels to really become known to the public. The great advantage of biodiesel is that it can be used in existing vehicles with little or no adaptation necessary. Cars running on BioEthanol, which is produced from agricultural crops, sugar cane or bio-mass, are governed by the same law of physics as those using gasoline. That means both emit CO2, as an inevitable consequence of the combustion process. But there is a crucial difference: burning ethanol, in effect, recycles the CO2 because it has already been removed from the atmosphere by photosynthesis during the natural growth process.
Along with the traditional methods we have new advancements in the renewable energy production. One of such examples include Engineers Tapping Algae Cells for Electricity :With the help of photosynthesis plants convert light energy to chemical energy. This chemical energy is stored in the bonds of sugars they use for food. Photosynthesis happens inside a chloroplast. Chloroplasts are considered as the cellular powerhouses that make sugars and impart leaves and algae a green hue. During photosynthesis water is split into oxygen, protons and electrons. When sunrays fall on the leaves and reach the chloroplast, electrons get excited and attain higher energy level. These excited electrons are caught by proteins. The electrons are passed through a series of proteins. These proteins utilize more of the
electrons’ energy to synthesize sugars until the entire electron’s energy is exhausted. Now researchers intercepted the electrons just after they had been excited by light and were at their highest energy levels. They put the gold electrodesinside the chloroplasts of algae cells, and tapped the electrons to create a tiny electrical current. It may be the beginning of the production of “high efficiency” bioelectricity. This will be a clean and green source of energy but minus carbon dioxide. The cell remains alive throughout the whole process. When cells start the photosynthesis, the electrodes attract electrons and produce tiny electric current.

The tryptophan operon of E.coli.

Unlike lack operon tryptophan operon is an anabolic operon, which means that the structural genes are only transcribed when the amino acid tryptophan is absent from the source i.e. When the amino acid is available the structural genes are not synthesized. The enzymes are not required and hence the operon is shut off. The operon model was elucidated by Charles Yonofsky and his colleagues. The operon model consists of the following genes.
1) Structural genes - The structural genes are coded from A to the letter E and encoded for the enzymes required for tryptophan biosynthesis and the gene spans 6800basepairs.
TrpA - tryptophan synthase α
TrpB - tryptophan synthase β
TrpC - PRA Isomerase and InGP synthase
TrpD - Anthranilate synthase 2
TrpE - Anthranilate synthase 1.

2)The promoter and the operator region of 150 bp upstream to the structural gene TrpE.

3) Leader region of 162basepairs, situated between the operator and TrpE. And within the leader region the attenuator site is present. The leader region and its role is briefly explained below under regulation of operon by attenuation.

4) The Regulatory gene - TrpR upstream to the promoter. The promoter is 150bp in length

The Regulation of the Tryptophan operon.
1) Regulation by "Repression" - The Tryptophan operon is under the negative control just like the lac operon, but it is repressible whereas lac operon is inducible operon. By repressible i mean that the effector molecule can repress the operon. The operon is regulated by Repression by the transcription of the TrpR region i.e the Repressor gene which encodes for the "Aporepressor protein." However the Aporepressor protein is not an active Repressor itself, hence it binds with tryptophan to produce an active Repressor. This active Repressor binds to the operator thereby preventing the transcription of the structural genes by blocking the path for Rna polymerase. This phenomenon is known as "Repression" and it reduces Tryptophan biosynthesis by 70 fold hence reducing the cellular try levels.
In the absence of tryptophan the operon is turned on because no active repressor can be formed hence the operator is free for Rna polymerase to bind and carry on transcription of the structural genes.

Regulation of Tryptophan operon by "Attenuation" - To understand the attenuation mechanism we must first understand the details of the Leader region which consists of 4 regions - 1,2,3,4. And among these 1,2 2,3 and 3,4 are complementary. The region 1 consist the tryptophan coding sequence i.e. UGG UGG from 54-59 and region 4 consist of the stop coding sequence i.e. UGA from 69-71. The base pairing at 1 and 2 region causes pause signal, The base pairing at 3 and 4 region causes termination signal and the base pairing at 2 and 3 region causes the anti termination signal.
Mechanism - The model here is based on the fact that Transcription and Translation in prokaryotes is carried out as coupled process due to the lack of a membrane bound nucleus. Hence here the Ribosome position plays an important role in regulation which is ultimately decided by the Leader region. It can be explained as follows.
A) In the absence of Tryptophan - In the absence of Tryptophan the trpt.Rna.trp levels drops hence the Ribosome translating the mRna stalls at the Trp codons (54-49). Therefore the leader peptide is not completed. The Ribosome blocks the region 1, hence the region 2 and 3 base pairing occurs. Which is an anti termination signal therefore the Polymerase continues translating past the attenuator region and the structural genes. Therefore the Trp operon is turned on in the absence of Tryptophan.
B) In the presence of Tryptophan - In the presence of Tryptophan, sufficient trptRnatrp's are present, hence the Ribosome translate the mrna and finally stalls at the stop region on the Leader peptide. The stop codon is region 2 and (69-71) region. The covering of region 2 by Ribosome facilitates region 3 and 4 base pairing which encodes for the termination signal. Hence the Rna polymerase stalls there and the structural genes are not transcribed. The Trp operon is shut of In the presence of Tryptophan.

3) Regulation of Tryptophan operon by Feed back inhibition - If the amino acid Tryptophan accumulates at a faster rate than utilized then the feed back inhibition is triggered. The end product of the biosynthetic pathway recognize the 1st enzyme of the pathway and inacivates it by altering its confirmation hence the pathway is shut off. Once the conc falls the product is dissociated and the enabling pathway resumes.

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