ANGIOSPERMS

ANGIOSPERMS

1. The term "angiosperms" derives from the two Greek words : angeion meaning "vessels" and sperma meaning "seeds".

2. Angiosperms (flowering plants) are the largest group of plants on earth.

3. Approximately 270,000 known species alive today.

4. Angiosperms include all plants that have flowers and account for approximately 80% of all known living plants.

5. Angiosperms means " covered seeds" have flowers, have fruits with seeds.

Live everywhere- dominants plants in the  world.

6. 260,000 species (88% of plant kingdom).

Angiosperms are most successful and advanced plant on earth.

  

Evolutionary Development of Angiosperms:-

1. Angiosperms evolved during the late Cretaceous period, about 125-100 million years ago.

2. This leaf imprint shows a ficus speciosissiva an Angiosperms that flourished during the Cretaceous period.

3. A large number of pollinating insects also appeared during this same time.

4. Advancements over gymnosperm: angiosperms have flowers- many use pollinators.

5. Fruits and seeds adapted for dispersal.

6. Double fertilization of endosperm in the seed.

Characteristics of Angiosperms

1. Angiosperms have developed flowers and fruits.

2. Flowers serves as the reproductive organs for the plants.

3. Flowers have a wide array of colors, shapes and smells all of the which are for the purpose of attracting pollinators.

1. Roots, stems and leaves.

2. Xylem and phloem.

4. Xylem- conveys water and dissolved minerals from the roots to the shoots.

5. Pholem- transports food made in the leaves to the roots and developing leaves and fruits.

6. They are Heterosporous.

Terminologies:-

a. Androecium- bearing one or more stamens.

b. Gynoecium- bearing one or more carpels.

c. Bisexual (perfect) flower- containing both stamens and carpels.

d. Unisexual (imperfect) flower- having only stamen or carpels.

Distribution of Angiosperms:-

1. One reason for this dominance is the relatively high photosynthetic capacity of their leaves.

2. They occupy every habitat on earth except extreme environment such as the highest mountain tops, the regions immediately surrounding the poles and deepest oceans.

3. They lives as Epiphytes, (i.e. living on other plants).

4. They occur abundantly in-

Shallows of rivers and fresh water lakes.

To a lesser extent, in Salt lakes and in the sea.

 Angiosperms life cycle:-

Flower has male and female sex organs.

Flower structure and it's part:-

1. Male sex organs: stamens, composed of anther- organ that produces pollen (male gametophyte).

2. Female sex organs- the carpel.

3. Ovary is the enlarged basal portion of carpel that contains the ovules (females gametophyte).

4. The stigma is the receptive portionof the carpel for pollen grains to adhere.

5. Non- reproductive parts; sepals (green) are the outermost whorl of leaf like bracts.

6. Petals (usually colored) are the inner whorl of leaf-like bracts.

7. Both can have various shaped and colors.

SEEDS:-

Endosperm is stored food tissues for the embryo to grow. Mature ovule becomes the seed coat and fruits.

Monocot vs Dicot

1. Angiosperms are divided into monocots and dicots.

2. As the zygote grows into the embryo, the first leaves of the young sporophyte develop and are called as cotyledons (seed leaves).

3. Monocots have one cotyledons (corns, lily etc).

4. Dicots have two cotyledons (beans, oak etc).

Comparing Monocots vs Dicots

Economic Importance of Angiosperms

The flowering plants have a number of uses as food, specifically as grains, sugars, vegetables, fruits, oils, nuts and spices.

In addition, plants and their products serve a number of other need such as dyes, fibres, timber, fuel, medicines, and ornaments.

Thank you🙏

BASIC TERMS OF GENETIC

GENETIC

"Genetic is collective study of heredity and variations". 

                          OR

"Genetics is a field of biology that studies how traits are passed from parents to their offspring".

Genetic term is given by William Bateson in the year 1905.

Heredity- Transformation of genetic character from one generation to another.

Variation- Individual of same species have same differences.

There are two types of Variation

1. Somatic variation- they are non inheritable.

2. Germinal/blastogenic variation- they transfer from one generation to another. i.e. inheritable 

a. Continuous (occurs due to crossing over)

b. Discontinuous (occurs due to mutations)

G. J. Mendel is father of genetics. He gave basic principles of genetics in the year 1866.

W. Bateson is father of morden genetics.

Morgan is father of experimental genetics. He did experiments on Drosophila and proposed concept like linkage, sex linkage, crosiing over, criss-cross inheritance, linkage map of Drosophila.

  A. Garrod is father of human genetics and Biochemical genetics. He discovered first human metabolic Disorder, i.e. Alkaptonuria ( Balck urine disease). He gave concept of one-mutant gene one-metabolic block.

TERMS OF GENETICS:-

Gene, allele, locus, homologous chromosomes, Dominant, Recessive, homozygous, heterozygous, gamete formation, phenotype, genotype.

Cell

GENE- A gene is the basic physical and functional unit of heredity that controls a particular trait of an organism.

HOMOLOGOUS CHROMOSOME- At the same locus , same character of gene is present are called homologous chromosomes.

Example- In human  46 chromosomes are present in 23 pairs.

maternal and paternal having same character of gene, at the same location; means both have same gene for eye colour.

LOCUS- Particular location of gene on  chromosomes.

ALLELE-  An allele is an alternate form of same gene, located on same locus on the homologous chromosomes.

                           OR

Allele are the gene which is coding for the same character but not for same trait. (Alternate form of gene)

Character- eye colour.

Trait- Blue, black, brown etc.

Alleles were first defined by Gregor Mendel in the law of segregation.

DOMINANT- A genetic trait is considered dominant if it is expressed in a person who has only one copy of that gene. A dominant trait is opposed to a Recessive trait which is expressed only when two copies of the gene are present.

RECESSIVE- A recessive gene is a gene whose effects are masked in the presence of a Dominant gene. Every organism that has DNA packed into chromosomes has two alleles, or forms of a gene , for each gene ; one inherited from their mother and one inherited from their father. A Recessive gene is only expressed when an organism has two recessive alleles for that gene.

This is also known as Being homozygous recessive. If an organism has one dominant and one recessive allele, it will show the dominant trait.

HOMOZYGOUS- Homozygous is a word that refers to a particular gene that has identical alleles on both homologous chromosome. It is referred to by two capital letters (XX) for a dominant trait, and two small letters (xx) for a Recessive trait.

HETEROZYGOUS- Gene come in pairs, called alleles and each pair is located in a specific position (locus) on a chromosome. If the two alleles at a locus are identical to eachother, they are Homozygous; if they are different from one another, they are Heterozygous.

GENOTYPE- Genetic makeup.

An organism genotype is the set of gene in its DNA responsible for the particular trait.

PHENOTYPE- physical features/apperance.

An organism phenotype is the physical expression of those gene.

                             OR

All the observable characteristics of an organism that results from the interaction of its genotype with the environment. Example- colour, shape, size.

GAMETE FORMATION

Gametes are formed through a process of cell division called meiosis. This two-step division process produces four haploid daughter cells.

Haploid cells contain only one set of chromosomes. When the haploid male and female gametes unite in a process called fertilization, they form zygote. The zygote is diploid and contain two sets of chromosomes.

Thank you👍

                         

GENE THERAPY

GENE THERAPY

Gene therapy is when DNA is introduced into a patient to treat a genetic disease. The new DNA usually contains a functioning gene to correct the effects of a disease-causing mutation.In the future, this technique may allow doctors to treat a disorder by inserting a gene into a patient’s cells instead of using drugs or surgery. Researchers are testing several approaches to gene therapy, including:

• Replacing a mutated gene that causes disease with a healthy copy of the gene.

• Inactivating, or “knocking out,” a mutated gene that is functioning improperly.

• Introducing a new gene into the body to help fight a disease.

Although gene therapy is a promising treatment option for a number of diseases (including inherited disorders, some types of cancer, and certain viral infections), the technique remains risky and is still under study to make sure that it will be safe and effective. Gene therapy is currently being tested only for diseases that have no other cures.

TYPES OF GENE THERAPY

There are two different types of gene therapy depending on which types of cells are treated:

• Somatic gene therapy: transfer of a section of DNA to any cell of the body that doesn’t produce sperm or eggs. Effects of gene therapy will not be passed onto the patient’s children.
• Germline gene therapy: transfer of a section of DNA to cells that produce eggs or sperm. Effects of gene therapy will be passed onto the patient’s children and subsequent generations.

GENE THERAPY WORK

Gene therapy is designed to introduce genetic material into cells to compensate for abnormal genes or to make a beneficial protein. If a mutated gene causes a necessary protein to be faulty or missing, gene therapy may be able to introduce a normal copy of the gene to restore the function of the protein.

A gene that is inserted directly into a cell usually does not function. Instead, a carrier called a vector is genetically engineered to deliver the gene. Certain viruses are often used as vectors because they can deliver the new gene by infecting the cell. The viruses are modified so they can't cause disease when used in people. Some types of virus, such as retroviruses, integrate their genetic material (including the new gene) into a chromosome in the human cell. Other viruses, such as adenoviruses, introduce their DNA into the nucleus of the cell, but the DNA is not integrated into a chromosome.

The vector can be injected or given intravenously (by IV) directly into a specific tissue in the body, where it is taken up by individual cells. Alternately, a sample of the patient's cells can be removed and exposed to the vector in a laboratory setting. The cells containing the vector are then returned to the patient. If the treatment is successful, the new gene delivered by the vector will make a functioning protein.

Researchers must overcome many technical challenges before gene therapy will be a practical approach to treating disease. For example, scientists must find better ways to deliver genes and target them to particular cells. They must also ensure that new genes are precisely controlled by the body.

A new gene is inserted directly into a cell. A carrier called a vector is genetically engineered to deliver the gene. An adenovirus introduces the DNA into the nucleus of the cell, but the DNA is not integrated into a chromosome.

IMPORTANCE OF GENE THERAPY

Genes that are flawed and do not work properly can cause disease. Gene therapy is a technique for correcting defective genes responsible for disease development. Researchers may use one of several approaches for correcting faulty genes:

• A normal gene may be inserted into a nonspecific location within the genome to replace a nonfunctional gene. This approach is most common.
• An abnormal gene could be swapped for a normal gene through homologous recombination.
• The abnormal gene could be repaired through selective reverse mutation, which returns the gene to its normal function.
• The regulation (the degree to which a gene is turned on or off) of a particular gene could be altered.

GENE THERAPY FOR SPECIFIC DISORDERS

Gene therapy holds promise for treating a wide range of diseases, such as cancer, cystic fibrosis, heart disease, diabetes, hemophilia and AIDS. Researchers are still studying how and when to use gene therapy. Currently, in the United States, gene therapy is available only as part of a clinical trial.

Thank you👍

GENE CLONING AND ITS SIGNIFICANCE

DNA cloning 

“DNA cloning is a molecular biology technique which is used for the creation of exact copies or clones of a particular gene or DNA.”

The production of exact copies of a particular gene or DNA sequence using genetic engineering techniques is called gene cloning.

• The term “gene cloning,” “DNA cloning,” “molecular cloning,” and “recombinant DNA technology” all refer to same technique.
• When DNA is extracted from an organism, all its genes are obtained. In gene (DNA) cloning a particular gene is copied forming “clones”.
• Cloning is one method used for isolation and amplification of gene of interest.

DNA cloning can be achieved by two different methods:

1. Cell based DNA cloning
2. Cell-free DNA cloning (PCR)

Requirements of Gene Cloning:-

1. DNA fragment containing the desired genes to be cloned.
2. Restriction enzymes and ligase enzymes.
3. Vectors – to carry, maintain and replicate cloned gene in host cell.
4. Host cell– in which recombinant DNA can replicate.
5. Steps of gene Cloning:
6. The  basic 7 steps involved in gene cloning are:

1. Isolation of DNA [gene of interest] fragments to be cloned.
2. Insertion of isolated DNA into a suitable vector to form recombinant DNA.
3. Introduction of recombinant DNA into a suitable organism known as host.
4. Selection of transformed host cells and identification of the clone containing the gene of interest.
5. Multiplication/Expression of the introduced Gene in the host.
6. Isolation of multiple gene copies/Protein expressed by the gene.
7. Purification of the isolated gene copy/protein.

A. Isolation of the DNA fragment or gene

1. The target DNA or gene to be cloned must be first isolated. A gene of interest is a fragment of gene whose prod­uct (a protein, enzyme or a hormone) interests us. For example, gene encoding for the hormone insulin.
2. The desired gene may be isolated by using restriction endonuclease (RE) enzyme, which cut DNA at specific recognition nucleotide se­quences known as restriction sites towards the inner region (hence endonuclease) producing blunt or sticky ends.
3. Sometimes, reverse transcriptase enzyme may also be used which synthesizes complementary DNA strand of the desired gene using its mRNA.

B. Selection of suitable cloning vector

• The vector is a carrier molecule which can carry the gene of interest (GI) into a host, replicate there along with the GI making its multiple copies.
• The cloning vectors are limited to the size of insert that they can carry. Depending on the size and the application of the insert the suitable vector is selected.
• The different types of vectors available for cloning are plasmids, bacteriophages, bacterial artificial chromosomes (BACs), yeast artificial chromosomes (YACs) and mammalian artificial chromosomes (MACs).
• However, the most commonly used cloning vectors include plasmids and bacteriophages (phage λ) beside all the other available vectors.

C. Essential Characteristics of Cloning Vectors

All cloning vectors are carrier DNA molecules. These carrier molecules should have few common features in general such as:

• It must be self-replicating inside host cell.
• It must possess a unique restriction site for RE enzymes.
• Introduction of donor DNA fragment must not interfere with replication property of the vector.
• It must possess some marker gene such that it can be used for later identification of recombinant cell (usually an antibiotic resistance gene that is absent in the host cell).
• They should be easily isolated from host cell.

D. Formation of Recombinant DNA

• The plasmid vector is cut open by the same RE enzyme used for isolation of donor DNA fragment.
• The mixture of donor DNA fragment and plasmid vector are mixed together.
• In the presence of DNA ligase, base pairing of donor DNA fragment and plasmid vector occurs.
• The result­ing DNA molecule is a hybrid of two DNA molecules – the GI and the vector. In the ter­minology of genetics this intermixing of dif­ferent DNA strands is called recombination.
• Hence, this new hybrid DNA molecule is also called a recombinant DNA molecule and the technology is referred to as the recom­binant DNA technology.

E. Transformation of recombinant vector into suitable host

• The recombinant vector is transformed into suitable host cell mostly, a bacterial cell.
• This is done either for one or both of the following reasons:
  • To replicate the recombinant DNA mol­ecule in order to get the multiple copies of the GI.
  • To allow the expression of the GI such that it produces its needed protein product.

• Some bacteria are naturally transformable; they take up the recombinant vector automatically.

For example: Bacillus, Haemophillus, Helicobacter pylori, which are naturally competent.

• Some other bacteria, on the other hand require the incorporation by artificial methods such as Ca⁺⁺ ion treatment, electroporation, etc.

F. Isolation of Recombinant Cells

• The transformation process generates a mixed population of transformed and non-trans- formed host cells.
• The selection process involves filtering the transformed host cells only.
• For isolation of recombinant cell from non-recombinant cell, marker gene of plasmid vector is employed.
• For examples, PBR322 plasmid vector contains different marker gene (Ampicillin resistant gene and Tetracycline resistant gene. When pst1 RE is used it knock out Ampicillin resistant gene from the plasmid, so that the recombinant cell become sensitive to Ampicillin.

G. Multiplication of Selected Host Cells

• Once transformed host cells are separated by the screening process; becomes necessary to provide them optimum parameters to grow and multiply.
• In this step the transformed host cells are introduced into fresh culture media .
• At this stage the host cells divide and re-divide along with the replication of the recom­binant DNA carried by them.
• If the aim is obtaining numerous copies of GI, then simply replication of the host cell is allowed. But for obtaining the product of interest, favourable conditions must be provided such that the GI in the vector expresses the product of interest.

H. Isolation and Purification of the Product

• The next step involves isolation of the multiplied GI attached with the vector or of the protein encoded by it.
• This is followed by purification of the isolated gene copy/protein. 
• 

ITS SIGNIFICANCE

• A particular gene can be isolated and its nucleotide sequence determined
• Control sequences of DNA can be identified & analyzed
• Protein/enzyme/RNA function can be investigated
• Mutations can be identified, e.g. gene defects related to specific diseases Organisms can be ‘engineered’ for specific purposes, e.g. insulin production, insect resistance, etc.
• DNA cloning can be used to make proteins such as insulin with biomedical techniques.
• It is used to develop recombinant versions of the non-functional gene to understand the functioning of the normal gene. This is applied in gene therapies also.
• It helps to analyse the effect of mutation on a particular gene.

Thank you👍

Albinism Disorder

Principal of Inheritance and Variations

HUMAN GENETICS DISORDER

An inherited medical condition caused by a DNA abnormality.

Basically two types:-

1. Chromosomal abnormalities

2. Gene Related human disorder

a. Autosomal disorder

      1. Dominant

       2. Recessive

b. Sex (gene disorder)

ALBINISM

 

1. It is autosomal recessive genetic disorder.

2. A group of inherited disorders characterised by little or no melanin production.

3. This condition increases the risk of skin cancer.

4. Albinism Disorder also known as achromasia.

5. Tryosinase enzyme is absent.

6. Individual lack dark pigment melanin in skin, hair and Iris.

Thank you👍

Alkaptonuria Disorder

Principal of Inheritance and variations

ALKAPTONURIA

It is an gene mutation in autosome recessive type. The metabolic defect is the deficiency of homogenticis acid oxidase enzyme. It's an autosomal recessive condition. It is compatible with fairly normal life.

First inborn metabolic disorder described by A. Garrod. 

CAUSE- Defect in the enzyme homogentisate oxidase, that catalysed oxidation of homogentisate to maleylactoactate. 

Homogentisate accumulates in blood and body tissues and is excreted in large amounts in urine.

CHARACTERISTICS FEATURE-

1. The urine of alkaptonuria patients become Dark after being exposed to air.

2. The alkapton imparts a characteristic black-brown color to urine. 

3. Alkaptonuria is a harmless condition.

4. Later in life deposition of dark colored alkapton pigments in connective tissues and bones occur.

5. This results in black pigmentation of the sclera, ear, nose and cheeks and the clinical condition is known as Ochronosis.

6. Ochronosis leads to tissue damage and may develop joint pain, arthritis and backache.

DIAGNOSIS-

1. The urine sample of patients of alkaptonuria turns dark on standing in air.

2. The urine gives positive test with ferric chloride and silver nitrate due to reducing activity of homogentisate.

3. Benedict's test is strongly positive.

TREATMENT-

1. Since alkaptonuria is not considered life threatening, this condition is not treated.

2. Later in life, the Symptoms of arthritis may be treated but the condition itself is not.

3. No specific treatment is required.

4. But minimal protein intake with phenylalanine less than 500gm/day is recommended.

Thank you👍